[openafs.git] / src / rx / rx.c

/*
 * Copyright 2000, International Business Machines Corporation and others.
 * All Rights Reserved.
 * 
 * This software has been released under the terms of the IBM Public
 * License.  For details, see the LICENSE file in the top-level source
 * directory or online at http://www.openafs.org/dl/license10.html
 */

/* RX:  Extended Remote Procedure Call */

#include <afsconfig.h>
#ifdef  KERNEL
#include "afs/param.h"
#else
#include <afs/param.h>
#endif


#ifdef KERNEL
#include "afs/sysincludes.h"
#include "afsincludes.h"
#ifndef UKERNEL
#include "h/types.h"
#include "h/time.h"
#include "h/stat.h"
#ifdef  AFS_OSF_ENV
#include <net/net_globals.h>
#endif /* AFS_OSF_ENV */
#ifdef AFS_LINUX20_ENV
#include "h/socket.h"
#endif
#include "netinet/in.h"
#ifdef AFS_SUN57_ENV
#include "inet/common.h"
#include "inet/ip.h"
#include "inet/ip_ire.h"
#endif
#include "afs/afs_args.h"
#include "afs/afs_osi.h"
#ifdef RX_KERNEL_TRACE
#include "rx_kcommon.h"
#endif
#if     (defined(AFS_AUX_ENV) || defined(AFS_AIX_ENV))
#include "h/systm.h"
#endif
#ifdef RXDEBUG
#undef RXDEBUG                  /* turn off debugging */
#endif /* RXDEBUG */
#if defined(AFS_SGI_ENV)
#include "sys/debug.h"
#endif
#include "afsint.h"
#ifdef  AFS_OSF_ENV
#undef kmem_alloc
#undef kmem_free
#undef mem_alloc
#undef mem_free
#undef register
#endif /* AFS_OSF_ENV */
#else /* !UKERNEL */
#include "afs/sysincludes.h"
#include "afsincludes.h"
#endif /* !UKERNEL */
#include "afs/lock.h"
#include "rx_kmutex.h"
#include "rx_kernel.h"
#include "rx_clock.h"
#include "rx_queue.h"
#include "rx.h"
#include "rx_globals.h"
#include "rx_trace.h"
#define AFSOP_STOP_RXCALLBACK   210     /* Stop CALLBACK process */
#define AFSOP_STOP_AFS          211     /* Stop AFS process */
#define AFSOP_STOP_BKG          212     /* Stop BKG process */
#include "afsint.h"
extern afs_int32 afs_termState;
#ifdef AFS_AIX41_ENV
#include "sys/lockl.h"
#include "sys/lock_def.h"
#endif /* AFS_AIX41_ENV */
# include "rxgen_consts.h"
#else /* KERNEL */
# include <sys/types.h>
# include <string.h>
# include <stdarg.h>
# include <errno.h>
# ifdef HAVE_STDINT_H
#  include <stdint.h>
# endif
#ifdef AFS_NT40_ENV
# include <stdlib.h>
# include <fcntl.h>
# include <afs/afsutil.h>
# include <WINNT\afsreg.h>
#else
# include <sys/socket.h>
# include <sys/file.h>
# include <netdb.h>
# include <sys/stat.h>
# include <netinet/in.h>
# include <sys/time.h>
#endif
# include "rx.h"
# include "rx_user.h"
# include "rx_clock.h"
# include "rx_queue.h"
# include "rx_globals.h"
# include "rx_trace.h"
# include <afs/rxgen_consts.h>
#endif /* KERNEL */

#ifndef KERNEL
#ifdef AFS_PTHREAD_ENV
#ifndef AFS_NT40_ENV
int (*registerProgram) (pid_t, char *) = 0;
int (*swapNameProgram) (pid_t, const char *, char *) = 0;
#endif
#else
int (*registerProgram) (PROCESS, char *) = 0;
int (*swapNameProgram) (PROCESS, const char *, char *) = 0;
#endif
#endif

/* Local static routines */
static void rxi_DestroyConnectionNoLock(struct rx_connection *conn);
#ifdef RX_ENABLE_LOCKS
static void rxi_SetAcksInTransmitQueue(struct rx_call *call);
#endif

#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
struct rx_tq_debug {
    afs_int32 rxi_start_aborted;        /* rxi_start awoke after rxi_Send in error. */
    afs_int32 rxi_start_in_error;
} rx_tq_debug;
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */

/*
 * rxi_rpc_peer_stat_cnt counts the total number of peer stat structures
 * currently allocated within rx.  This number is used to allocate the
 * memory required to return the statistics when queried.
 */

static unsigned int rxi_rpc_peer_stat_cnt;

/*
 * rxi_rpc_process_stat_cnt counts the total number of local process stat
 * structures currently allocated within rx.  The number is used to allocate
 * the memory required to return the statistics when queried.
 */

static unsigned int rxi_rpc_process_stat_cnt;

#if !defined(offsetof)
#include <stddef.h>             /* for definition of offsetof() */
#endif

#ifdef AFS_PTHREAD_ENV
#include <assert.h>

/*
 * Use procedural initialization of mutexes/condition variables
 * to ease NT porting
 */

extern afs_kmutex_t rx_stats_mutex;
extern afs_kmutex_t rx_waiting_mutex;
extern afs_kmutex_t rx_quota_mutex;
extern afs_kmutex_t rx_pthread_mutex;
extern afs_kmutex_t rx_packets_mutex;
extern afs_kmutex_t des_init_mutex;
extern afs_kmutex_t des_random_mutex;
extern afs_kmutex_t rx_clock_mutex;
extern afs_kmutex_t rxi_connCacheMutex;
extern afs_kmutex_t rx_event_mutex;
extern afs_kmutex_t osi_malloc_mutex;
extern afs_kmutex_t event_handler_mutex;
extern afs_kmutex_t listener_mutex;
extern afs_kmutex_t rx_if_init_mutex;
extern afs_kmutex_t rx_if_mutex;
extern afs_kmutex_t rxkad_client_uid_mutex;
extern afs_kmutex_t rxkad_random_mutex;

extern afs_kcondvar_t rx_event_handler_cond;
extern afs_kcondvar_t rx_listener_cond;

static afs_kmutex_t epoch_mutex;
static afs_kmutex_t rx_init_mutex;
static afs_kmutex_t rx_debug_mutex;
static afs_kmutex_t rx_rpc_stats;

static void
rxi_InitPthread(void)
{
    MUTEX_INIT(&rx_clock_mutex, "clock", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_stats_mutex, "stats", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_waiting_mutex, "waiting", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_quota_mutex, "quota", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_pthread_mutex, "pthread", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_packets_mutex, "packets", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&epoch_mutex, "epoch", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_init_mutex, "init", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_event_mutex, "event", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&des_init_mutex, "des", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&des_random_mutex, "random", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&osi_malloc_mutex, "malloc", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&event_handler_mutex, "event handler", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rxi_connCacheMutex, "conn cache", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&listener_mutex, "listener", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_if_init_mutex, "if init", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_if_mutex, "if", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rxkad_client_uid_mutex, "uid", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rxkad_random_mutex, "rxkad random", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_debug_mutex, "debug", MUTEX_DEFAULT, 0);

    assert(pthread_cond_init
           (&rx_event_handler_cond, (const pthread_condattr_t *)0) == 0);
    assert(pthread_cond_init(&rx_listener_cond, (const pthread_condattr_t *)0)
           == 0);
    assert(pthread_key_create(&rx_thread_id_key, NULL) == 0);
    assert(pthread_key_create(&rx_ts_info_key, NULL) == 0);
 
    rxkad_global_stats_init();

    MUTEX_INIT(&rx_rpc_stats, "rx_rpc_stats", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_freePktQ_lock, "rx_freePktQ_lock", MUTEX_DEFAULT, 0);
#ifdef  RX_ENABLE_LOCKS
#ifdef RX_LOCKS_DB
    rxdb_init();
#endif /* RX_LOCKS_DB */
    MUTEX_INIT(&freeSQEList_lock, "freeSQEList lock", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_freeCallQueue_lock, "rx_freeCallQueue_lock", MUTEX_DEFAULT,
               0);
    CV_INIT(&rx_waitingForPackets_cv, "rx_waitingForPackets_cv", CV_DEFAULT,
            0);
    MUTEX_INIT(&rx_peerHashTable_lock, "rx_peerHashTable_lock", MUTEX_DEFAULT,
               0);
    MUTEX_INIT(&rx_connHashTable_lock, "rx_connHashTable_lock", MUTEX_DEFAULT,
               0);
    MUTEX_INIT(&rx_serverPool_lock, "rx_serverPool_lock", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rxi_keyCreate_lock, "rxi_keyCreate_lock", MUTEX_DEFAULT, 0);
#endif /* RX_ENABLE_LOCKS */
}

pthread_once_t rx_once_init = PTHREAD_ONCE_INIT;
#define INIT_PTHREAD_LOCKS \
assert(pthread_once(&rx_once_init, rxi_InitPthread)==0)
/*
 * The rx_stats_mutex mutex protects the following global variables:
 * rxi_lowConnRefCount
 * rxi_lowPeerRefCount
 * rxi_nCalls
 * rxi_Alloccnt
 * rxi_Allocsize
 * rx_tq_debug
 * rx_stats
 */

/*
 * The rx_quota_mutex mutex protects the following global variables:
 * rxi_dataQuota
 * rxi_minDeficit
 * rxi_availProcs
 * rxi_totalMin
 */

/* 
 * The rx_freePktQ_lock protects the following global variables:
 * rx_nFreePackets 
 */

/*
 * The rx_packets_mutex mutex protects the following global variables:
 * rx_nPackets
 * rx_TSFPQLocalMax
 * rx_TSFPQGlobSize
 * rx_TSFPQMaxProcs
 */

/*
 * The rx_pthread_mutex mutex protects the following global variables:
 * rxi_pthread_hinum
 */
#else
#define INIT_PTHREAD_LOCKS
#endif


/* Variables for handling the minProcs implementation.  availProcs gives the
 * number of threads available in the pool at this moment (not counting dudes
 * executing right now).  totalMin gives the total number of procs required
 * for handling all minProcs requests.  minDeficit is a dynamic variable
 * tracking the # of procs required to satisfy all of the remaining minProcs
 * demands.
 * For fine grain locking to work, the quota check and the reservation of
 * a server thread has to come while rxi_availProcs and rxi_minDeficit
 * are locked. To this end, the code has been modified under #ifdef
 * RX_ENABLE_LOCKS so that quota checks and reservation occur at the
 * same time. A new function, ReturnToServerPool() returns the allocation.
 * 
 * A call can be on several queue's (but only one at a time). When
 * rxi_ResetCall wants to remove the call from a queue, it has to ensure
 * that no one else is touching the queue. To this end, we store the address
 * of the queue lock in the call structure (under the call lock) when we
 * put the call on a queue, and we clear the call_queue_lock when the
 * call is removed from a queue (once the call lock has been obtained).
 * This allows rxi_ResetCall to safely synchronize with others wishing
 * to manipulate the queue.
 */

#if defined(RX_ENABLE_LOCKS) && defined(KERNEL)
static afs_kmutex_t rx_rpc_stats;
void rxi_StartUnlocked(struct rxevent *event, void *call,
                       void *arg1, int istack);
#endif

/* We keep a "last conn pointer" in rxi_FindConnection. The odds are 
** pretty good that the next packet coming in is from the same connection 
** as the last packet, since we're send multiple packets in a transmit window.
*/
struct rx_connection *rxLastConn = 0;

#ifdef RX_ENABLE_LOCKS
/* The locking hierarchy for rx fine grain locking is composed of these
 * tiers:
 *
 * rx_connHashTable_lock - synchronizes conn creation, rx_connHashTable access
 * conn_call_lock - used to synchonize rx_EndCall and rx_NewCall
 * call->lock - locks call data fields.
 * These are independent of each other:
 *      rx_freeCallQueue_lock
 *      rxi_keyCreate_lock
 * rx_serverPool_lock
 * freeSQEList_lock
 *
 * serverQueueEntry->lock
 * rx_rpc_stats
 * rx_peerHashTable_lock - locked under rx_connHashTable_lock
 * peer->lock - locks peer data fields.
 * conn_data_lock - that more than one thread is not updating a conn data
 *                  field at the same time.
 * rx_freePktQ_lock
 *
 * lowest level:
 *      multi_handle->lock
 *      rxevent_lock
 *      rx_stats_mutex
 *
 * Do we need a lock to protect the peer field in the conn structure?
 *      conn->peer was previously a constant for all intents and so has no
 *      lock protecting this field. The multihomed client delta introduced
 *      a RX code change : change the peer field in the connection structure
 *      to that remote inetrface from which the last packet for this
 *      connection was sent out. This may become an issue if further changes
 *      are made.
 */
#define SET_CALL_QUEUE_LOCK(C, L) (C)->call_queue_lock = (L)
#define CLEAR_CALL_QUEUE_LOCK(C) (C)->call_queue_lock = NULL
#ifdef RX_LOCKS_DB
/* rxdb_fileID is used to identify the lock location, along with line#. */
static int rxdb_fileID = RXDB_FILE_RX;
#endif /* RX_LOCKS_DB */
#else /* RX_ENABLE_LOCKS */
#define SET_CALL_QUEUE_LOCK(C, L)
#define CLEAR_CALL_QUEUE_LOCK(C)
#endif /* RX_ENABLE_LOCKS */
struct rx_serverQueueEntry *rx_waitForPacket = 0;
struct rx_serverQueueEntry *rx_waitingForPacket = 0;

/* ------------Exported Interfaces------------- */

/* This function allows rxkad to set the epoch to a suitably random number
 * which rx_NewConnection will use in the future.  The principle purpose is to
 * get rxnull connections to use the same epoch as the rxkad connections do, at
 * least once the first rxkad connection is established.  This is important now
 * that the host/port addresses aren't used in FindConnection: the uniqueness
 * of epoch/cid matters and the start time won't do. */

#ifdef AFS_PTHREAD_ENV
/*
 * This mutex protects the following global variables:
 * rx_epoch
 */

#define LOCK_EPOCH MUTEX_ENTER(&epoch_mutex)
#define UNLOCK_EPOCH MUTEX_EXIT(&epoch_mutex)
#else
#define LOCK_EPOCH
#define UNLOCK_EPOCH
#endif /* AFS_PTHREAD_ENV */

void
rx_SetEpoch(afs_uint32 epoch)
{
    LOCK_EPOCH;
    rx_epoch = epoch;
    UNLOCK_EPOCH;
}

/* Initialize rx.  A port number may be mentioned, in which case this
 * becomes the default port number for any service installed later.
 * If 0 is provided for the port number, a random port will be chosen
 * by the kernel.  Whether this will ever overlap anything in
 * /etc/services is anybody's guess...  Returns 0 on success, -1 on
 * error. */
#ifndef AFS_NT40_ENV
static
#endif
int rxinit_status = 1;
#ifdef AFS_PTHREAD_ENV
/*
 * This mutex protects the following global variables:
 * rxinit_status
 */

#define LOCK_RX_INIT MUTEX_ENTER(&rx_init_mutex)
#define UNLOCK_RX_INIT MUTEX_EXIT(&rx_init_mutex)
#else
#define LOCK_RX_INIT
#define UNLOCK_RX_INIT
#endif

int
rx_InitHost(u_int host, u_int port)
{
#ifdef KERNEL
    osi_timeval_t tv;
#else /* KERNEL */
    struct timeval tv;
#endif /* KERNEL */
    char *htable, *ptable;
    int tmp_status;
    
    SPLVAR;
    
    INIT_PTHREAD_LOCKS;
    LOCK_RX_INIT;
    if (rxinit_status == 0) {
        tmp_status = rxinit_status;
        UNLOCK_RX_INIT;
        return tmp_status;      /* Already started; return previous error code. */
    }
#ifdef RXDEBUG
    rxi_DebugInit();
#endif
#ifdef AFS_NT40_ENV
    if (afs_winsockInit() < 0)
        return -1;
#endif

#ifndef KERNEL
    /*
     * Initialize anything necessary to provide a non-premptive threading
     * environment.
     */
    rxi_InitializeThreadSupport();
#endif

    /* Allocate and initialize a socket for client and perhaps server
     * connections. */

    rx_socket = rxi_GetHostUDPSocket(host, (u_short) port);
    if (rx_socket == OSI_NULLSOCKET) {
        UNLOCK_RX_INIT;
        return RX_ADDRINUSE;
    }
#if defined(RX_ENABLE_LOCKS) && defined(KERNEL)
#ifdef RX_LOCKS_DB
    rxdb_init();
#endif /* RX_LOCKS_DB */
    MUTEX_INIT(&rx_stats_mutex, "rx_stats_mutex", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_waiting_mutex, "rx_waiting_mutex", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_quota_mutex, "rx_quota_mutex", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_pthread_mutex, "rx_pthread_mutex", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_packets_mutex, "rx_packets_mutex", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_rpc_stats, "rx_rpc_stats", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_freePktQ_lock, "rx_freePktQ_lock", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&freeSQEList_lock, "freeSQEList lock", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&rx_freeCallQueue_lock, "rx_freeCallQueue_lock", MUTEX_DEFAULT,
               0);
    CV_INIT(&rx_waitingForPackets_cv, "rx_waitingForPackets_cv", CV_DEFAULT,
            0);
    MUTEX_INIT(&rx_peerHashTable_lock, "rx_peerHashTable_lock", MUTEX_DEFAULT,
               0);
    MUTEX_INIT(&rx_connHashTable_lock, "rx_connHashTable_lock", MUTEX_DEFAULT,
               0);
    MUTEX_INIT(&rx_serverPool_lock, "rx_serverPool_lock", MUTEX_DEFAULT, 0);
#if defined(AFS_HPUX110_ENV)
    if (!uniprocessor)
        rx_sleepLock = alloc_spinlock(LAST_HELD_ORDER - 10, "rx_sleepLock");
#endif /* AFS_HPUX110_ENV */
#endif /* RX_ENABLE_LOCKS && KERNEL */

    rxi_nCalls = 0;
    rx_connDeadTime = 12;
    rx_tranquil = 0;            /* reset flag */
    memset(&rx_stats, 0, sizeof(struct rx_statistics));
    htable = (char *)
        osi_Alloc(rx_hashTableSize * sizeof(struct rx_connection *));
    PIN(htable, rx_hashTableSize * sizeof(struct rx_connection *));     /* XXXXX */
    memset(htable, 0, rx_hashTableSize * sizeof(struct rx_connection *));
    ptable = (char *)osi_Alloc(rx_hashTableSize * sizeof(struct rx_peer *));
    PIN(ptable, rx_hashTableSize * sizeof(struct rx_peer *));   /* XXXXX */
    memset(ptable, 0, rx_hashTableSize * sizeof(struct rx_peer *));

    /* Malloc up a bunch of packets & buffers */
    rx_nFreePackets = 0;
    queue_Init(&rx_freePacketQueue);
    rxi_NeedMorePackets = FALSE;
#ifdef RX_ENABLE_TSFPQ
    rx_nPackets = 0;    /* in TSFPQ version, rx_nPackets is managed by rxi_MorePackets* */
    rxi_MorePacketsTSFPQ(rx_extraPackets + RX_MAX_QUOTA + 2, RX_TS_FPQ_FLUSH_GLOBAL, 0);
#else /* RX_ENABLE_TSFPQ */
    rx_nPackets = rx_extraPackets + RX_MAX_QUOTA + 2;   /* fudge */
    rxi_MorePackets(rx_nPackets);
#endif /* RX_ENABLE_TSFPQ */
    rx_CheckPackets();

    NETPRI;

    clock_Init();

#if defined(AFS_NT40_ENV) && !defined(AFS_PTHREAD_ENV)
    tv.tv_sec = clock_now.sec;
    tv.tv_usec = clock_now.usec;
    srand((unsigned int)tv.tv_usec);
#else
    osi_GetTime(&tv);
#endif
    if (port) {
        rx_port = port;
    } else {
#if defined(KERNEL) && !defined(UKERNEL)
        /* Really, this should never happen in a real kernel */
        rx_port = 0;
#else
        struct sockaddr_in addr;
#ifdef AFS_NT40_ENV
        int addrlen = sizeof(addr);
#else
        socklen_t addrlen = sizeof(addr);
#endif
        if (getsockname((intptr_t)rx_socket, (struct sockaddr *)&addr, &addrlen)) {
            rx_Finalize();
            return -1;
        }
        rx_port = addr.sin_port;
#endif
    }
    rx_stats.minRtt.sec = 9999999;
#ifdef  KERNEL
    rx_SetEpoch(tv.tv_sec | 0x80000000);
#else
    rx_SetEpoch(tv.tv_sec);     /* Start time of this package, rxkad
                                 * will provide a randomer value. */
#endif
    MUTEX_ENTER(&rx_quota_mutex);
    rxi_dataQuota += rx_extraQuota; /* + extra pkts caller asked to rsrv */
    MUTEX_EXIT(&rx_quota_mutex);
    /* *Slightly* random start time for the cid.  This is just to help
     * out with the hashing function at the peer */
    rx_nextCid = ((tv.tv_sec ^ tv.tv_usec) << RX_CIDSHIFT);
    rx_connHashTable = (struct rx_connection **)htable;
    rx_peerHashTable = (struct rx_peer **)ptable;

    rx_lastAckDelay.sec = 0;
    rx_lastAckDelay.usec = 400000;      /* 400 milliseconds */
    rx_hardAckDelay.sec = 0;
    rx_hardAckDelay.usec = 100000;      /* 100 milliseconds */
    rx_softAckDelay.sec = 0;
    rx_softAckDelay.usec = 100000;      /* 100 milliseconds */

    rxevent_Init(20, rxi_ReScheduleEvents);

    /* Initialize various global queues */
    queue_Init(&rx_idleServerQueue);
    queue_Init(&rx_incomingCallQueue);
    queue_Init(&rx_freeCallQueue);

#if defined(AFS_NT40_ENV) && !defined(KERNEL)
    /* Initialize our list of usable IP addresses. */
    rx_GetIFInfo();
#endif

    /* Start listener process (exact function is dependent on the
     * implementation environment--kernel or user space) */
    rxi_StartListener();

    USERPRI;
    tmp_status = rxinit_status = 0;
    UNLOCK_RX_INIT;
    return tmp_status;
}

int
rx_Init(u_int port)
{
    return rx_InitHost(htonl(INADDR_ANY), port);
}

/* called with unincremented nRequestsRunning to see if it is OK to start
 * a new thread in this service.  Could be "no" for two reasons: over the
 * max quota, or would prevent others from reaching their min quota.
 */
#ifdef RX_ENABLE_LOCKS
/* This verion of QuotaOK reserves quota if it's ok while the
 * rx_serverPool_lock is held.  Return quota using ReturnToServerPool().
 */
static int
QuotaOK(struct rx_service *aservice)
{
    /* check if over max quota */
    if (aservice->nRequestsRunning >= aservice->maxProcs) {
        return 0;
    }

    /* under min quota, we're OK */
    /* otherwise, can use only if there are enough to allow everyone
     * to go to their min quota after this guy starts.
     */

    MUTEX_ENTER(&rx_quota_mutex);
    if ((aservice->nRequestsRunning < aservice->minProcs)
        || (rxi_availProcs > rxi_minDeficit)) {
        aservice->nRequestsRunning++;
        /* just started call in minProcs pool, need fewer to maintain
         * guarantee */
        if (aservice->nRequestsRunning <= aservice->minProcs)
            rxi_minDeficit--;
        rxi_availProcs--;
        MUTEX_EXIT(&rx_quota_mutex);
        return 1;
    }
    MUTEX_EXIT(&rx_quota_mutex);

    return 0;
}

static void
ReturnToServerPool(struct rx_service *aservice)
{
    aservice->nRequestsRunning--;
    MUTEX_ENTER(&rx_quota_mutex);
    if (aservice->nRequestsRunning < aservice->minProcs)
        rxi_minDeficit++;
    rxi_availProcs++;
    MUTEX_EXIT(&rx_quota_mutex);
}

#else /* RX_ENABLE_LOCKS */
static int
QuotaOK(struct rx_service *aservice)
{
    int rc = 0;
    /* under min quota, we're OK */
    if (aservice->nRequestsRunning < aservice->minProcs)
        return 1;

    /* check if over max quota */
    if (aservice->nRequestsRunning >= aservice->maxProcs)
        return 0;

    /* otherwise, can use only if there are enough to allow everyone
     * to go to their min quota after this guy starts.
     */
    if (rxi_availProcs > rxi_minDeficit)
        rc = 1;
    return rc;
}
#endif /* RX_ENABLE_LOCKS */

#ifndef KERNEL
/* Called by rx_StartServer to start up lwp's to service calls.
   NExistingProcs gives the number of procs already existing, and which
   therefore needn't be created. */
void
rxi_StartServerProcs(int nExistingProcs)
{
    struct rx_service *service;
    int i;
    int maxdiff = 0;
    int nProcs = 0;

    /* For each service, reserve N processes, where N is the "minimum"
     * number of processes that MUST be able to execute a request in parallel,
     * at any time, for that process.  Also compute the maximum difference
     * between any service's maximum number of processes that can run
     * (i.e. the maximum number that ever will be run, and a guarantee
     * that this number will run if other services aren't running), and its
     * minimum number.  The result is the extra number of processes that
     * we need in order to provide the latter guarantee */
    for (i = 0; i < RX_MAX_SERVICES; i++) {
        int diff;
        service = rx_services[i];
        if (service == (struct rx_service *)0)
            break;
        nProcs += service->minProcs;
        diff = service->maxProcs - service->minProcs;
        if (diff > maxdiff)
            maxdiff = diff;
    }
    nProcs += maxdiff;          /* Extra processes needed to allow max number requested to run in any given service, under good conditions */
    nProcs -= nExistingProcs;   /* Subtract the number of procs that were previously created for use as server procs */
    for (i = 0; i < nProcs; i++) {
        rxi_StartServerProc(rx_ServerProc, rx_stackSize);
    }
}
#endif /* KERNEL */

#ifdef AFS_NT40_ENV
/* This routine is only required on Windows */
void
rx_StartClientThread(void)
{
#ifdef AFS_PTHREAD_ENV
    pthread_t pid;
    pid = pthread_self();
#endif /* AFS_PTHREAD_ENV */
}
#endif /* AFS_NT40_ENV */

/* This routine must be called if any services are exported.  If the
 * donateMe flag is set, the calling process is donated to the server
 * process pool */
void
rx_StartServer(int donateMe)
{
    struct rx_service *service;
    int i;
    SPLVAR;
    clock_NewTime();

    NETPRI;
    /* Start server processes, if necessary (exact function is dependent
     * on the implementation environment--kernel or user space).  DonateMe
     * will be 1 if there is 1 pre-existing proc, i.e. this one.  In this
     * case, one less new proc will be created rx_StartServerProcs.
     */
    rxi_StartServerProcs(donateMe);

    /* count up the # of threads in minProcs, and add set the min deficit to
     * be that value, too.
     */
    for (i = 0; i < RX_MAX_SERVICES; i++) {
        service = rx_services[i];
        if (service == (struct rx_service *)0)
            break;
        MUTEX_ENTER(&rx_quota_mutex);
        rxi_totalMin += service->minProcs;
        /* below works even if a thread is running, since minDeficit would
         * still have been decremented and later re-incremented.
         */
        rxi_minDeficit += service->minProcs;
        MUTEX_EXIT(&rx_quota_mutex);
    }

    /* Turn on reaping of idle server connections */
    rxi_ReapConnections(NULL, NULL, NULL);

    USERPRI;

    if (donateMe) {
#ifndef AFS_NT40_ENV
#ifndef KERNEL
        char name[32];
        static int nProcs;
#ifdef AFS_PTHREAD_ENV
        pid_t pid;
        pid = afs_pointer_to_int(pthread_self());
#else /* AFS_PTHREAD_ENV */
        PROCESS pid;
        LWP_CurrentProcess(&pid);
#endif /* AFS_PTHREAD_ENV */

        sprintf(name, "srv_%d", ++nProcs);
        if (registerProgram)
            (*registerProgram) (pid, name);
#endif /* KERNEL */
#endif /* AFS_NT40_ENV */
        rx_ServerProc(NULL);    /* Never returns */
    }
#ifdef RX_ENABLE_TSFPQ
    /* no use leaving packets around in this thread's local queue if
     * it isn't getting donated to the server thread pool. 
     */
    rxi_FlushLocalPacketsTSFPQ();
#endif /* RX_ENABLE_TSFPQ */
    return;
}

/* Create a new client connection to the specified service, using the
 * specified security object to implement the security model for this
 * connection. */
struct rx_connection *
rx_NewConnection(afs_uint32 shost, u_short sport, u_short sservice,
                 struct rx_securityClass *securityObject,
                 int serviceSecurityIndex)
{
    int hashindex, i;
    afs_int32 cid;
    struct rx_connection *conn;

    SPLVAR;

    clock_NewTime();
    dpf(("rx_NewConnection(host %x, port %u, service %u, securityObject %p, "
         "serviceSecurityIndex %d)\n",
         ntohl(shost), ntohs(sport), sservice, securityObject,
         serviceSecurityIndex));

    /* Vasilsi said: "NETPRI protects Cid and Alloc", but can this be true in
     * the case of kmem_alloc? */
    conn = rxi_AllocConnection();
#ifdef  RX_ENABLE_LOCKS
    MUTEX_INIT(&conn->conn_call_lock, "conn call lock", MUTEX_DEFAULT, 0);
    MUTEX_INIT(&conn->conn_data_lock, "conn data lock", MUTEX_DEFAULT, 0);
    CV_INIT(&conn->conn_call_cv, "conn call cv", CV_DEFAULT, 0);
#endif
    NETPRI;
    MUTEX_ENTER(&rx_connHashTable_lock);
    cid = (rx_nextCid += RX_MAXCALLS);
    conn->type = RX_CLIENT_CONNECTION;
    conn->cid = cid;
    conn->epoch = rx_epoch;
    conn->peer = rxi_FindPeer(shost, sport, 0, 1);
    conn->serviceId = sservice;
    conn->securityObject = securityObject;
    conn->securityData = (void *) 0;
    conn->securityIndex = serviceSecurityIndex;
    rx_SetConnDeadTime(conn, rx_connDeadTime);
    rx_SetConnSecondsUntilNatPing(conn, 0);
    conn->ackRate = RX_FAST_ACK_RATE;
    conn->nSpecific = 0;
    conn->specific = NULL;
    conn->challengeEvent = NULL;
    conn->delayedAbortEvent = NULL;
    conn->abortCount = 0;
    conn->error = 0;
    for (i = 0; i < RX_MAXCALLS; i++) {
        conn->twind[i] = rx_initSendWindow;
        conn->rwind[i] = rx_initReceiveWindow;
    }

    RXS_NewConnection(securityObject, conn);
    hashindex =
        CONN_HASH(shost, sport, conn->cid, conn->epoch, RX_CLIENT_CONNECTION);

    conn->refCount++;           /* no lock required since only this thread knows... */
    conn->next = rx_connHashTable[hashindex];
    rx_connHashTable[hashindex] = conn;
    if (rx_stats_active)
        rx_MutexIncrement(rx_stats.nClientConns, rx_stats_mutex);
    MUTEX_EXIT(&rx_connHashTable_lock);
    USERPRI;
    return conn;
}

void
rx_SetConnDeadTime(struct rx_connection *conn, int seconds)
{
    /* The idea is to set the dead time to a value that allows several
     * keepalives to be dropped without timing out the connection. */
    conn->secondsUntilDead = MAX(seconds, 6);
    conn->secondsUntilPing = conn->secondsUntilDead / 6;
}

int rxi_lowPeerRefCount = 0;
int rxi_lowConnRefCount = 0;

/*
 * Cleanup a connection that was destroyed in rxi_DestroyConnectioNoLock.
 * NOTE: must not be called with rx_connHashTable_lock held.
 */
void
rxi_CleanupConnection(struct rx_connection *conn)
{
    /* Notify the service exporter, if requested, that this connection
     * is being destroyed */
    if (conn->type == RX_SERVER_CONNECTION && conn->service->destroyConnProc)
        (*conn->service->destroyConnProc) (conn);

    /* Notify the security module that this connection is being destroyed */
    RXS_DestroyConnection(conn->securityObject, conn);

    /* If this is the last connection using the rx_peer struct, set its
     * idle time to now. rxi_ReapConnections will reap it if it's still
     * idle (refCount == 0) after rx_idlePeerTime (60 seconds) have passed.
     */
    MUTEX_ENTER(&rx_peerHashTable_lock);
    if (conn->peer->refCount < 2) {
        conn->peer->idleWhen = clock_Sec();
        if (conn->peer->refCount < 1) {
            conn->peer->refCount = 1;
            if (rx_stats_active) {
                MUTEX_ENTER(&rx_stats_mutex);
                rxi_lowPeerRefCount++;
                MUTEX_EXIT(&rx_stats_mutex);
            }
        }
    }
    conn->peer->refCount--;
    MUTEX_EXIT(&rx_peerHashTable_lock);

    if (rx_stats_active)
    {
        if (conn->type == RX_SERVER_CONNECTION)
            rx_MutexDecrement(rx_stats.nServerConns, rx_stats_mutex);
        else
            rx_MutexDecrement(rx_stats.nClientConns, rx_stats_mutex);
    }
#ifndef KERNEL
    if (conn->specific) {
        int i;
        for (i = 0; i < conn->nSpecific; i++) {
            if (conn->specific[i] && rxi_keyCreate_destructor[i])
                (*rxi_keyCreate_destructor[i]) (conn->specific[i]);
            conn->specific[i] = NULL;
        }
        free(conn->specific);
    }
    conn->specific = NULL;
    conn->nSpecific = 0;
#endif /* !KERNEL */

    MUTEX_DESTROY(&conn->conn_call_lock);
    MUTEX_DESTROY(&conn->conn_data_lock);
    CV_DESTROY(&conn->conn_call_cv);

    rxi_FreeConnection(conn);
}

/* Destroy the specified connection */
void
rxi_DestroyConnection(struct rx_connection *conn)
{
    MUTEX_ENTER(&rx_connHashTable_lock);
    rxi_DestroyConnectionNoLock(conn);
    /* conn should be at the head of the cleanup list */
    if (conn == rx_connCleanup_list) {
        rx_connCleanup_list = rx_connCleanup_list->next;
        MUTEX_EXIT(&rx_connHashTable_lock);
        rxi_CleanupConnection(conn);
    }
#ifdef RX_ENABLE_LOCKS
    else {
        MUTEX_EXIT(&rx_connHashTable_lock);
    }
#endif /* RX_ENABLE_LOCKS */
}

static void
rxi_DestroyConnectionNoLock(struct rx_connection *conn)
{
    struct rx_connection **conn_ptr;
    int havecalls = 0;
    struct rx_packet *packet;
    int i;
    SPLVAR;

    clock_NewTime();

    NETPRI;
    MUTEX_ENTER(&conn->conn_data_lock);
    if (conn->refCount > 0)
        conn->refCount--;
    else {
        if (rx_stats_active) {
            MUTEX_ENTER(&rx_stats_mutex);
            rxi_lowConnRefCount++;
            MUTEX_EXIT(&rx_stats_mutex);
        }
    }

    if ((conn->refCount > 0) || (conn->flags & RX_CONN_BUSY)) {
        /* Busy; wait till the last guy before proceeding */
        MUTEX_EXIT(&conn->conn_data_lock);
        USERPRI;
        return;
    }

    /* If the client previously called rx_NewCall, but it is still
     * waiting, treat this as a running call, and wait to destroy the
     * connection later when the call completes. */
    if ((conn->type == RX_CLIENT_CONNECTION)
        && (conn->flags & RX_CONN_MAKECALL_WAITING)) {
        conn->flags |= RX_CONN_DESTROY_ME;
        MUTEX_EXIT(&conn->conn_data_lock);
        USERPRI;
        return;
    }
    MUTEX_EXIT(&conn->conn_data_lock);

    /* Check for extant references to this connection */
    for (i = 0; i < RX_MAXCALLS; i++) {
        struct rx_call *call = conn->call[i];
        if (call) {
            havecalls = 1;
            if (conn->type == RX_CLIENT_CONNECTION) {
                MUTEX_ENTER(&call->lock);
                if (call->delayedAckEvent) {
                    /* Push the final acknowledgment out now--there
                     * won't be a subsequent call to acknowledge the
                     * last reply packets */
                    rxevent_Cancel(call->delayedAckEvent, call,
                                   RX_CALL_REFCOUNT_DELAY);
                    if (call->state == RX_STATE_PRECALL
                        || call->state == RX_STATE_ACTIVE) {
                        rxi_SendAck(call, 0, 0, RX_ACK_DELAY, 0);
                    } else {
                        rxi_AckAll(NULL, call, 0);
                    }
                }
                MUTEX_EXIT(&call->lock);
            }
        }
    }
#ifdef RX_ENABLE_LOCKS
    if (!havecalls) {
        if (MUTEX_TRYENTER(&conn->conn_data_lock)) {
            MUTEX_EXIT(&conn->conn_data_lock);
        } else {
            /* Someone is accessing a packet right now. */
            havecalls = 1;
        }
    }
#endif /* RX_ENABLE_LOCKS */

    if (havecalls) {
        /* Don't destroy the connection if there are any call
         * structures still in use */
        MUTEX_ENTER(&conn->conn_data_lock);
        conn->flags |= RX_CONN_DESTROY_ME;
        MUTEX_EXIT(&conn->conn_data_lock);
        USERPRI;
        return;
    }

    if (conn->natKeepAliveEvent) {
        rxi_NatKeepAliveOff(conn);
    }

    if (conn->delayedAbortEvent) {
        rxevent_Cancel(conn->delayedAbortEvent, (struct rx_call *)0, 0);
        packet = rxi_AllocPacket(RX_PACKET_CLASS_SPECIAL);
        if (packet) {
            MUTEX_ENTER(&conn->conn_data_lock);
            rxi_SendConnectionAbort(conn, packet, 0, 1);
            MUTEX_EXIT(&conn->conn_data_lock);
            rxi_FreePacket(packet);
        }
    }

    /* Remove from connection hash table before proceeding */
    conn_ptr =
        &rx_connHashTable[CONN_HASH
                          (peer->host, peer->port, conn->cid, conn->epoch,
                           conn->type)];
    for (; *conn_ptr; conn_ptr = &(*conn_ptr)->next) {
        if (*conn_ptr == conn) {
            *conn_ptr = conn->next;
            break;
        }
    }
    /* if the conn that we are destroying was the last connection, then we
     * clear rxLastConn as well */
    if (rxLastConn == conn)
        rxLastConn = 0;

    /* Make sure the connection is completely reset before deleting it. */
    /* get rid of pending events that could zap us later */
    if (conn->challengeEvent)
        rxevent_Cancel(conn->challengeEvent, (struct rx_call *)0, 0);
    if (conn->checkReachEvent)
        rxevent_Cancel(conn->checkReachEvent, (struct rx_call *)0, 0);
    if (conn->natKeepAliveEvent)
        rxevent_Cancel(conn->natKeepAliveEvent, (struct rx_call *)0, 0);

    /* Add the connection to the list of destroyed connections that
     * need to be cleaned up. This is necessary to avoid deadlocks
     * in the routines we call to inform others that this connection is
     * being destroyed. */
    conn->next = rx_connCleanup_list;
    rx_connCleanup_list = conn;
}

/* Externally available version */
void
rx_DestroyConnection(struct rx_connection *conn)
{
    SPLVAR;

    NETPRI;
    rxi_DestroyConnection(conn);
    USERPRI;
}

void
rx_GetConnection(struct rx_connection *conn)
{
    SPLVAR;

    NETPRI;
    MUTEX_ENTER(&conn->conn_data_lock);
    conn->refCount++;
    MUTEX_EXIT(&conn->conn_data_lock);
    USERPRI;
}

#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
/* Wait for the transmit queue to no longer be busy. 
 * requires the call->lock to be held */
static void rxi_WaitforTQBusy(struct rx_call *call) {
    while (call->flags & RX_CALL_TQ_BUSY) {
        call->flags |= RX_CALL_TQ_WAIT;
        call->tqWaiters++;
#ifdef RX_ENABLE_LOCKS
        osirx_AssertMine(&call->lock, "rxi_WaitforTQ lock");
        CV_WAIT(&call->cv_tq, &call->lock);
#else /* RX_ENABLE_LOCKS */
        osi_rxSleep(&call->tq);
#endif /* RX_ENABLE_LOCKS */
        call->tqWaiters--;
        if (call->tqWaiters == 0) {
            call->flags &= ~RX_CALL_TQ_WAIT;
        }
    }
}
#endif

/* Start a new rx remote procedure call, on the specified connection.
 * If wait is set to 1, wait for a free call channel; otherwise return
 * 0.  Maxtime gives the maximum number of seconds this call may take,
 * after rx_NewCall returns.  After this time interval, a call to any
 * of rx_SendData, rx_ReadData, etc. will fail with RX_CALL_TIMEOUT.
 * For fine grain locking, we hold the conn_call_lock in order to 
 * to ensure that we don't get signalle after we found a call in an active
 * state and before we go to sleep.
 */
struct rx_call *
rx_NewCall(struct rx_connection *conn)
{
    int i;
    struct rx_call *call;
    struct clock queueTime;
    SPLVAR;

    clock_NewTime();
    dpf(("rx_NewCall(conn %"AFS_PTR_FMT")\n", conn));

    NETPRI;
    clock_GetTime(&queueTime);
    MUTEX_ENTER(&conn->conn_call_lock);

    /*
     * Check if there are others waiting for a new call.
     * If so, let them go first to avoid starving them.
     * This is a fairly simple scheme, and might not be
     * a complete solution for large numbers of waiters.
     * 
     * makeCallWaiters keeps track of the number of 
     * threads waiting to make calls and the 
     * RX_CONN_MAKECALL_WAITING flag bit is used to 
     * indicate that there are indeed calls waiting.
     * The flag is set when the waiter is incremented.
     * It is only cleared in rx_EndCall when 
     * makeCallWaiters is 0.  This prevents us from 
     * accidently destroying the connection while it
     * is potentially about to be used.
     */
    MUTEX_ENTER(&conn->conn_data_lock);
    if (conn->makeCallWaiters) {
        conn->flags |= RX_CONN_MAKECALL_WAITING;
        conn->makeCallWaiters++;
        MUTEX_EXIT(&conn->conn_data_lock);

#ifdef  RX_ENABLE_LOCKS
        CV_WAIT(&conn->conn_call_cv, &conn->conn_call_lock);
#else
        osi_rxSleep(conn);
#endif
        MUTEX_ENTER(&conn->conn_data_lock);
        conn->makeCallWaiters--;
    } 
    MUTEX_EXIT(&conn->conn_data_lock);

    for (;;) {
        for (i = 0; i < RX_MAXCALLS; i++) {
            call = conn->call[i];
            if (call) {
                MUTEX_ENTER(&call->lock);
                if (call->state == RX_STATE_DALLY) {
                    rxi_ResetCall(call, 0);
                    (*call->callNumber)++;
                    break;
                }
                MUTEX_EXIT(&call->lock);
            } else {
                call = rxi_NewCall(conn, i);
                break;
            }
        }
        if (i < RX_MAXCALLS) {
            break;
        }
        MUTEX_ENTER(&conn->conn_data_lock);
        conn->flags |= RX_CONN_MAKECALL_WAITING;
        conn->makeCallWaiters++;
        MUTEX_EXIT(&conn->conn_data_lock);

#ifdef  RX_ENABLE_LOCKS
        CV_WAIT(&conn->conn_call_cv, &conn->conn_call_lock);
#else
        osi_rxSleep(conn);
#endif
        MUTEX_ENTER(&conn->conn_data_lock);
        conn->makeCallWaiters--;
        MUTEX_EXIT(&conn->conn_data_lock);
    }
    /*
     * Wake up anyone else who might be giving us a chance to
     * run (see code above that avoids resource starvation).
     */
#ifdef  RX_ENABLE_LOCKS
    CV_BROADCAST(&conn->conn_call_cv);
#else
    osi_rxWakeup(conn);
#endif

    CALL_HOLD(call, RX_CALL_REFCOUNT_BEGIN);

    /* Client is initially in send mode */
    call->state = RX_STATE_ACTIVE;
    call->error = conn->error;
    if (call->error)
        call->mode = RX_MODE_ERROR;
    else
        call->mode = RX_MODE_SENDING;
    
    /* remember start time for call in case we have hard dead time limit */
    call->queueTime = queueTime;
    clock_GetTime(&call->startTime);
    hzero(call->bytesSent);
    hzero(call->bytesRcvd);

    /* Turn on busy protocol. */
    rxi_KeepAliveOn(call);

    MUTEX_EXIT(&call->lock);
    MUTEX_EXIT(&conn->conn_call_lock);
    USERPRI;

#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
    /* Now, if TQ wasn't cleared earlier, do it now. */
    MUTEX_ENTER(&call->lock);
    rxi_WaitforTQBusy(call);
    if (call->flags & RX_CALL_TQ_CLEARME) {
        rxi_ClearTransmitQueue(call, 1);
        /*queue_Init(&call->tq);*/
    }
    MUTEX_EXIT(&call->lock);
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */

    dpf(("rx_NewCall(call %"AFS_PTR_FMT")\n", call));
    return call;
}

int
rxi_HasActiveCalls(struct rx_connection *aconn)
{
    int i;
    struct rx_call *tcall;
    SPLVAR;

    NETPRI;
    for (i = 0; i < RX_MAXCALLS; i++) {
        if ((tcall = aconn->call[i])) {
            if ((tcall->state == RX_STATE_ACTIVE)
                || (tcall->state == RX_STATE_PRECALL)) {
                USERPRI;
                return 1;
            }
        }
    }
    USERPRI;
    return 0;
}

int
rxi_GetCallNumberVector(struct rx_connection *aconn,
                        afs_int32 * aint32s)
{
    int i;
    struct rx_call *tcall;
    SPLVAR;

    NETPRI;
    for (i = 0; i < RX_MAXCALLS; i++) {
        if ((tcall = aconn->call[i]) && (tcall->state == RX_STATE_DALLY))
            aint32s[i] = aconn->callNumber[i] + 1;
        else
            aint32s[i] = aconn->callNumber[i];
    }
    USERPRI;
    return 0;
}

int
rxi_SetCallNumberVector(struct rx_connection *aconn,
                        afs_int32 * aint32s)
{
    int i;
    struct rx_call *tcall;
    SPLVAR;

    NETPRI;
    for (i = 0; i < RX_MAXCALLS; i++) {
        if ((tcall = aconn->call[i]) && (tcall->state == RX_STATE_DALLY))
            aconn->callNumber[i] = aint32s[i] - 1;
        else
            aconn->callNumber[i] = aint32s[i];
    }
    USERPRI;
    return 0;
}

/* Advertise a new service.  A service is named locally by a UDP port
 * number plus a 16-bit service id.  Returns (struct rx_service *) 0
 * on a failure. 
 *
     char *serviceName;  Name for identification purposes (e.g. the
                         service name might be used for probing for
                         statistics) */
struct rx_service *
rx_NewServiceHost(afs_uint32 host, u_short port, u_short serviceId, 
                  char *serviceName, struct rx_securityClass **securityObjects,
                  int nSecurityObjects, 
                  afs_int32(*serviceProc) (struct rx_call * acall))
{
    osi_socket socket = OSI_NULLSOCKET;
    struct rx_service *tservice;
    int i;
    SPLVAR;

    clock_NewTime();

    if (serviceId == 0) {
        (osi_Msg
         "rx_NewService:  service id for service %s is not non-zero.\n",
         serviceName);
        return 0;
    }
    if (port == 0) {
        if (rx_port == 0) {
            (osi_Msg
             "rx_NewService: A non-zero port must be specified on this call if a non-zero port was not provided at Rx initialization (service %s).\n",
             serviceName);
            return 0;
        }
        port = rx_port;
        socket = rx_socket;
    }

    tservice = rxi_AllocService();
    NETPRI;
    for (i = 0; i < RX_MAX_SERVICES; i++) {
        struct rx_service *service = rx_services[i];
        if (service) {
            if (port == service->servicePort && host == service->serviceHost) {
                if (service->serviceId == serviceId) {
                    /* The identical service has already been
                     * installed; if the caller was intending to
                     * change the security classes used by this
                     * service, he/she loses. */
                    (osi_Msg
                     "rx_NewService: tried to install service %s with service id %d, which is already in use for service %s\n",
                     serviceName, serviceId, service->serviceName);
                    USERPRI;
                    rxi_FreeService(tservice);
                    return service;
                }
                /* Different service, same port: re-use the socket
                 * which is bound to the same port */
                socket = service->socket;
            }
        } else {
            if (socket == OSI_NULLSOCKET) {
                /* If we don't already have a socket (from another
                 * service on same port) get a new one */
                socket = rxi_GetHostUDPSocket(host, port);
                if (socket == OSI_NULLSOCKET) {
                    USERPRI;
                    rxi_FreeService(tservice);
                    return 0;
                }
            }
            service = tservice;
            service->socket = socket;
            service->serviceHost = host;
            service->servicePort = port;
            service->serviceId = serviceId;
            service->serviceName = serviceName;
            service->nSecurityObjects = nSecurityObjects;
            service->securityObjects = securityObjects;
            service->minProcs = 0;
            service->maxProcs = 1;
            service->idleDeadTime = 60;
            service->idleDeadErr = 0;
            service->connDeadTime = rx_connDeadTime;
            service->executeRequestProc = serviceProc;
            service->checkReach = 0;
            rx_services[i] = service;   /* not visible until now */
            USERPRI;
            return service;
        }
    }
    USERPRI;
    rxi_FreeService(tservice);
    (osi_Msg "rx_NewService: cannot support > %d services\n",
     RX_MAX_SERVICES);
    return 0;
}

/* Set configuration options for all of a service's security objects */

afs_int32 
rx_SetSecurityConfiguration(struct rx_service *service, 
                            rx_securityConfigVariables type,
                            void *value)
{
    int i;
    for (i = 0; i<service->nSecurityObjects; i++) {
        if (service->securityObjects[i]) {
            RXS_SetConfiguration(service->securityObjects[i], NULL, type, 
                                 value, NULL);
        }
    }
    return 0;
}

struct rx_service *
rx_NewService(u_short port, u_short serviceId, char *serviceName,
              struct rx_securityClass **securityObjects, int nSecurityObjects,
              afs_int32(*serviceProc) (struct rx_call * acall))
{
    return rx_NewServiceHost(htonl(INADDR_ANY), port, serviceId, serviceName, securityObjects, nSecurityObjects, serviceProc);
}

/* Generic request processing loop. This routine should be called
 * by the implementation dependent rx_ServerProc. If socketp is
 * non-null, it will be set to the file descriptor that this thread
 * is now listening on. If socketp is null, this routine will never
 * returns. */
void
rxi_ServerProc(int threadID, struct rx_call *newcall, osi_socket * socketp)
{
    struct rx_call *call;
    afs_int32 code;
    struct rx_service *tservice = NULL;

    for (;;) {
        if (newcall) {
            call = newcall;
            newcall = NULL;
        } else {
            call = rx_GetCall(threadID, tservice, socketp);
            if (socketp && *socketp != OSI_NULLSOCKET) {
                /* We are now a listener thread */
                return;
            }
        }

        /* if server is restarting( typically smooth shutdown) then do not
         * allow any new calls.
         */

        if (rx_tranquil && (call != NULL)) {
            SPLVAR;

            NETPRI;
            MUTEX_ENTER(&call->lock);

            rxi_CallError(call, RX_RESTARTING);
            rxi_SendCallAbort(call, (struct rx_packet *)0, 0, 0);

            MUTEX_EXIT(&call->lock);
            USERPRI;
        }
#ifdef  KERNEL
        if (afs_termState == AFSOP_STOP_RXCALLBACK) {
#ifdef RX_ENABLE_LOCKS
            AFS_GLOCK();
#endif /* RX_ENABLE_LOCKS */
            afs_termState = AFSOP_STOP_AFS;
            afs_osi_Wakeup(&afs_termState);
#ifdef RX_ENABLE_LOCKS
            AFS_GUNLOCK();
#endif /* RX_ENABLE_LOCKS */
            return;
        }
#endif

        tservice = call->conn->service;

        if (tservice->beforeProc)
            (*tservice->beforeProc) (call);

        code = call->conn->service->executeRequestProc(call);

        if (tservice->afterProc)
            (*tservice->afterProc) (call, code);

        rx_EndCall(call, code);
        if (rx_stats_active) {
            MUTEX_ENTER(&rx_stats_mutex);
            rxi_nCalls++;
            MUTEX_EXIT(&rx_stats_mutex);
        }
    }
}


void
rx_WakeupServerProcs(void)
{
    struct rx_serverQueueEntry *np, *tqp;
    SPLVAR;

    NETPRI;
    MUTEX_ENTER(&rx_serverPool_lock);

#ifdef RX_ENABLE_LOCKS
    if (rx_waitForPacket)
        CV_BROADCAST(&rx_waitForPacket->cv);
#else /* RX_ENABLE_LOCKS */
    if (rx_waitForPacket)
        osi_rxWakeup(rx_waitForPacket);
#endif /* RX_ENABLE_LOCKS */
    MUTEX_ENTER(&freeSQEList_lock);
    for (np = rx_FreeSQEList; np; np = tqp) {
        tqp = *(struct rx_serverQueueEntry **)np;
#ifdef RX_ENABLE_LOCKS
        CV_BROADCAST(&np->cv);
#else /* RX_ENABLE_LOCKS */
        osi_rxWakeup(np);
#endif /* RX_ENABLE_LOCKS */
    }
    MUTEX_EXIT(&freeSQEList_lock);
    for (queue_Scan(&rx_idleServerQueue, np, tqp, rx_serverQueueEntry)) {
#ifdef RX_ENABLE_LOCKS
        CV_BROADCAST(&np->cv);
#else /* RX_ENABLE_LOCKS */
        osi_rxWakeup(np);
#endif /* RX_ENABLE_LOCKS */
    }
    MUTEX_EXIT(&rx_serverPool_lock);
    USERPRI;
}

/* meltdown:
 * One thing that seems to happen is that all the server threads get
 * tied up on some empty or slow call, and then a whole bunch of calls
 * arrive at once, using up the packet pool, so now there are more 
 * empty calls.  The most critical resources here are server threads
 * and the free packet pool.  The "doreclaim" code seems to help in
 * general.  I think that eventually we arrive in this state: there
 * are lots of pending calls which do have all their packets present,
 * so they won't be reclaimed, are multi-packet calls, so they won't
 * be scheduled until later, and thus are tying up most of the free 
 * packet pool for a very long time.
 * future options:
 * 1.  schedule multi-packet calls if all the packets are present.  
 * Probably CPU-bound operation, useful to return packets to pool. 
 * Do what if there is a full window, but the last packet isn't here?
 * 3.  preserve one thread which *only* runs "best" calls, otherwise
 * it sleeps and waits for that type of call.
 * 4.  Don't necessarily reserve a whole window for each thread.  In fact, 
 * the current dataquota business is badly broken.  The quota isn't adjusted
 * to reflect how many packets are presently queued for a running call.
 * So, when we schedule a queued call with a full window of packets queued
 * up for it, that *should* free up a window full of packets for other 2d-class
 * calls to be able to use from the packet pool.  But it doesn't.
 *
 * NB.  Most of the time, this code doesn't run -- since idle server threads
 * sit on the idle server queue and are assigned by "...ReceivePacket" as soon
 * as a new call arrives.
 */
/* Sleep until a call arrives.  Returns a pointer to the call, ready
 * for an rx_Read. */
#ifdef RX_ENABLE_LOCKS
struct rx_call *
rx_GetCall(int tno, struct rx_service *cur_service, osi_socket * socketp)
{
    struct rx_serverQueueEntry *sq;
    struct rx_call *call = (struct rx_call *)0;
    struct rx_service *service = NULL;
    SPLVAR;

    MUTEX_ENTER(&freeSQEList_lock);

    if ((sq = rx_FreeSQEList)) {
        rx_FreeSQEList = *(struct rx_serverQueueEntry **)sq;
        MUTEX_EXIT(&freeSQEList_lock);
    } else {                    /* otherwise allocate a new one and return that */
        MUTEX_EXIT(&freeSQEList_lock);
        sq = (struct rx_serverQueueEntry *)
            rxi_Alloc(sizeof(struct rx_serverQueueEntry));
        MUTEX_INIT(&sq->lock, "server Queue lock", MUTEX_DEFAULT, 0);
        CV_INIT(&sq->cv, "server Queue lock", CV_DEFAULT, 0);
    }

    MUTEX_ENTER(&rx_serverPool_lock);
    if (cur_service != NULL) {
        ReturnToServerPool(cur_service);
    }
    while (1) {
        if (queue_IsNotEmpty(&rx_incomingCallQueue)) {
            struct rx_call *tcall, *ncall, *choice2 = NULL;

            /* Scan for eligible incoming calls.  A call is not eligible
             * if the maximum number of calls for its service type are
             * already executing */
            /* One thread will process calls FCFS (to prevent starvation),
             * while the other threads may run ahead looking for calls which
             * have all their input data available immediately.  This helps 
             * keep threads from blocking, waiting for data from the client. */
            for (queue_Scan(&rx_incomingCallQueue, tcall, ncall, rx_call)) {
                service = tcall->conn->service;
                if (!QuotaOK(service)) {
                    continue;
                }
                MUTEX_ENTER(&rx_pthread_mutex);
                if (tno == rxi_fcfs_thread_num
                    || !tcall->queue_item_header.next) {
                    MUTEX_EXIT(&rx_pthread_mutex);
                    /* If we're the fcfs thread , then  we'll just use 
                     * this call. If we haven't been able to find an optimal 
                     * choice, and we're at the end of the list, then use a 
                     * 2d choice if one has been identified.  Otherwise... */
                    call = (choice2 ? choice2 : tcall);
                    service = call->conn->service;
                } else {
                    MUTEX_EXIT(&rx_pthread_mutex);
                    if (!queue_IsEmpty(&tcall->rq)) {
                        struct rx_packet *rp;
                        rp = queue_First(&tcall->rq, rx_packet);
                        if (rp->header.seq == 1) {
                            if (!meltdown_1pkt
                                || (rp->header.flags & RX_LAST_PACKET)) {
                                call = tcall;
                            } else if (rxi_2dchoice && !choice2
                                       && !(tcall->flags & RX_CALL_CLEARED)
                                       && (tcall->rprev > rxi_HardAckRate)) {
                                choice2 = tcall;
                            } else
                                rxi_md2cnt++;
                        }
                    }
                }
                if (call) {
                    break;
                } else {
                    ReturnToServerPool(service);
                }
            }
        }

        if (call) {
            queue_Remove(call);
            MUTEX_EXIT(&rx_serverPool_lock);
            MUTEX_ENTER(&call->lock);

            if (call->flags & RX_CALL_WAIT_PROC) {
                call->flags &= ~RX_CALL_WAIT_PROC;
                MUTEX_ENTER(&rx_waiting_mutex);
                rx_nWaiting--;
                MUTEX_EXIT(&rx_waiting_mutex);
            }

            if (call->state != RX_STATE_PRECALL || call->error) {
                MUTEX_EXIT(&call->lock);
                MUTEX_ENTER(&rx_serverPool_lock);
                ReturnToServerPool(service);
                call = NULL;
                continue;
            }

            if (queue_IsEmpty(&call->rq)
                || queue_First(&call->rq, rx_packet)->header.seq != 1)
                rxi_SendAck(call, 0, 0, RX_ACK_DELAY, 0);

            CLEAR_CALL_QUEUE_LOCK(call);
            break;
        } else {
            /* If there are no eligible incoming calls, add this process
             * to the idle server queue, to wait for one */
            sq->newcall = 0;
            sq->tno = tno;
            if (socketp) {
                *socketp = OSI_NULLSOCKET;
            }
            sq->socketp = socketp;
            queue_Append(&rx_idleServerQueue, sq);
#ifndef AFS_AIX41_ENV
            rx_waitForPacket = sq;
#else
            rx_waitingForPacket = sq;
#endif /* AFS_AIX41_ENV */
            do {
                CV_WAIT(&sq->cv, &rx_serverPool_lock);
#ifdef  KERNEL
                if (afs_termState == AFSOP_STOP_RXCALLBACK) {
                    MUTEX_EXIT(&rx_serverPool_lock);
                    return (struct rx_call *)0;
                }
#endif
            } while (!(call = sq->newcall)
                     && !(socketp && *socketp != OSI_NULLSOCKET));
            MUTEX_EXIT(&rx_serverPool_lock);
            if (call) {
                MUTEX_ENTER(&call->lock);
            }
            break;
        }
    }

    MUTEX_ENTER(&freeSQEList_lock);
    *(struct rx_serverQueueEntry **)sq = rx_FreeSQEList;
    rx_FreeSQEList = sq;
    MUTEX_EXIT(&freeSQEList_lock);

    if (call) {
        clock_GetTime(&call->startTime);
        call->state = RX_STATE_ACTIVE;
        call->mode = RX_MODE_RECEIVING;
#ifdef RX_KERNEL_TRACE
        if (ICL_SETACTIVE(afs_iclSetp)) {
            int glockOwner = ISAFS_GLOCK();
            if (!glockOwner)
                AFS_GLOCK();
            afs_Trace3(afs_iclSetp, CM_TRACE_WASHERE, ICL_TYPE_STRING,
                       __FILE__, ICL_TYPE_INT32, __LINE__, ICL_TYPE_POINTER,
                       call);
            if (!glockOwner)
                AFS_GUNLOCK();
        }
#endif

        rxi_calltrace(RX_CALL_START, call);
        dpf(("rx_GetCall(port=%d, service=%d) ==> call %"AFS_PTR_FMT"\n",
             call->conn->service->servicePort, call->conn->service->serviceId,
             call));

        CALL_HOLD(call, RX_CALL_REFCOUNT_BEGIN);
        MUTEX_EXIT(&call->lock);
    } else {
        dpf(("rx_GetCall(socketp=%p, *socketp=0x%x)\n", socketp, *socketp));
    }

    return call;
}
#else /* RX_ENABLE_LOCKS */
struct rx_call *
rx_GetCall(int tno, struct rx_service *cur_service, osi_socket * socketp)
{
    struct rx_serverQueueEntry *sq;
    struct rx_call *call = (struct rx_call *)0, *choice2;
    struct rx_service *service = NULL;
    SPLVAR;

    NETPRI;
    MUTEX_ENTER(&freeSQEList_lock);

    if ((sq = rx_FreeSQEList)) {
        rx_FreeSQEList = *(struct rx_serverQueueEntry **)sq;
        MUTEX_EXIT(&freeSQEList_lock);
    } else {                    /* otherwise allocate a new one and return that */
        MUTEX_EXIT(&freeSQEList_lock);
        sq = (struct rx_serverQueueEntry *)
            rxi_Alloc(sizeof(struct rx_serverQueueEntry));
        MUTEX_INIT(&sq->lock, "server Queue lock", MUTEX_DEFAULT, 0);
        CV_INIT(&sq->cv, "server Queue lock", CV_DEFAULT, 0);
    }
    MUTEX_ENTER(&sq->lock);

    if (cur_service != NULL) {
        cur_service->nRequestsRunning--;
        if (cur_service->nRequestsRunning < cur_service->minProcs)
            rxi_minDeficit++;
        rxi_availProcs++;
    }
    if (queue_IsNotEmpty(&rx_incomingCallQueue)) {
        struct rx_call *tcall, *ncall;
        /* Scan for eligible incoming calls.  A call is not eligible
         * if the maximum number of calls for its service type are
         * already executing */
        /* One thread will process calls FCFS (to prevent starvation),
         * while the other threads may run ahead looking for calls which
         * have all their input data available immediately.  This helps 
         * keep threads from blocking, waiting for data from the client. */
        choice2 = (struct rx_call *)0;
        for (queue_Scan(&rx_incomingCallQueue, tcall, ncall, rx_call)) {
            service = tcall->conn->service;
            if (QuotaOK(service)) {
                MUTEX_ENTER(&rx_pthread_mutex);
                if (tno == rxi_fcfs_thread_num
                    || !tcall->queue_item_header.next) {
                    MUTEX_EXIT(&rx_pthread_mutex);
                    /* If we're the fcfs thread, then  we'll just use 
                     * this call. If we haven't been able to find an optimal 
                     * choice, and we're at the end of the list, then use a 
                     * 2d choice if one has been identified.  Otherwise... */
                    call = (choice2 ? choice2 : tcall);
                    service = call->conn->service;
                } else {
                    MUTEX_EXIT(&rx_pthread_mutex);
                    if (!queue_IsEmpty(&tcall->rq)) {
                        struct rx_packet *rp;
                        rp = queue_First(&tcall->rq, rx_packet);
                        if (rp->header.seq == 1
                            && (!meltdown_1pkt
                                || (rp->header.flags & RX_LAST_PACKET))) {
                            call = tcall;
                        } else if (rxi_2dchoice && !choice2
                                   && !(tcall->flags & RX_CALL_CLEARED)
                                   && (tcall->rprev > rxi_HardAckRate)) {
                            choice2 = tcall;
                        } else
                            rxi_md2cnt++;
                    }
                }
            }
            if (call)
                break;
        }
    }

    if (call) {
        queue_Remove(call);
        /* we can't schedule a call if there's no data!!! */
        /* send an ack if there's no data, if we're missing the
         * first packet, or we're missing something between first 
         * and last -- there's a "hole" in the incoming data. */
        if (queue_IsEmpty(&call->rq)
            || queue_First(&call->rq, rx_packet)->header.seq != 1
            || call->rprev != queue_Last(&call->rq, rx_packet)->header.seq)
            rxi_SendAck(call, 0, 0, RX_ACK_DELAY, 0);

        call->flags &= (~RX_CALL_WAIT_PROC);
        service->nRequestsRunning++;
        /* just started call in minProcs pool, need fewer to maintain
         * guarantee */
        if (service->nRequestsRunning <= service->minProcs)
            rxi_minDeficit--;
        rxi_availProcs--;
        rx_nWaiting--;
        /* MUTEX_EXIT(&call->lock); */
    } else {
        /* If there are no eligible incoming calls, add this process
         * to the idle server queue, to wait for one */
        sq->newcall = 0;
        if (socketp) {
            *socketp = OSI_NULLSOCKET;
        }
        sq->socketp = socketp;
        queue_Append(&rx_idleServerQueue, sq);
        do {
            osi_rxSleep(sq);
#ifdef  KERNEL
            if (afs_termState == AFSOP_STOP_RXCALLBACK) {
                USERPRI;
                rxi_Free(sq, sizeof(struct rx_serverQueueEntry));
                return (struct rx_call *)0;
            }
#endif
        } while (!(call = sq->newcall)
                 && !(socketp && *socketp != OSI_NULLSOCKET));
    }
    MUTEX_EXIT(&sq->lock);

    MUTEX_ENTER(&freeSQEList_lock);
    *(struct rx_serverQueueEntry **)sq = rx_FreeSQEList;
    rx_FreeSQEList = sq;
    MUTEX_EXIT(&freeSQEList_lock);

    if (call) {
        clock_GetTime(&call->startTime);
        call->state = RX_STATE_ACTIVE;
        call->mode = RX_MODE_RECEIVING;
#ifdef RX_KERNEL_TRACE
        if (ICL_SETACTIVE(afs_iclSetp)) {
            int glockOwner = ISAFS_GLOCK();
            if (!glockOwner)
                AFS_GLOCK();
            afs_Trace3(afs_iclSetp, CM_TRACE_WASHERE, ICL_TYPE_STRING,
                       __FILE__, ICL_TYPE_INT32, __LINE__, ICL_TYPE_POINTER,
                       call);
            if (!glockOwner)
                AFS_GUNLOCK();
        }
#endif

        rxi_calltrace(RX_CALL_START, call);
        dpf(("rx_GetCall(port=%d, service=%d) ==> call %p\n",
             call->conn->service->servicePort, call->conn->service->serviceId,
             call));
    } else {
        dpf(("rx_GetCall(socketp=%p, *socketp=0x%x)\n", socketp, *socketp));
    }

    USERPRI;

    return call;
}
#endif /* RX_ENABLE_LOCKS */



/* Establish a procedure to be called when a packet arrives for a
 * call.  This routine will be called at most once after each call,
 * and will also be called if there is an error condition on the or
 * the call is complete.  Used by multi rx to build a selection
 * function which determines which of several calls is likely to be a
 * good one to read from.  
 * NOTE: the way this is currently implemented it is probably only a
 * good idea to (1) use it immediately after a newcall (clients only)
 * and (2) only use it once.  Other uses currently void your warranty
 */
void
rx_SetArrivalProc(struct rx_call *call,
                  void (*proc) (struct rx_call * call,
                                        void * mh,
                                        int index),
                  void * handle, int arg)
{
    call->arrivalProc = proc;
    call->arrivalProcHandle = handle;
    call->arrivalProcArg = arg;
}

/* Call is finished (possibly prematurely).  Return rc to the peer, if
 * appropriate, and return the final error code from the conversation
 * to the caller */

afs_int32
rx_EndCall(struct rx_call *call, afs_int32 rc)
{
    struct rx_connection *conn = call->conn;
    struct rx_service *service;
    afs_int32 error;
    SPLVAR;



    dpf(("rx_EndCall(call %"AFS_PTR_FMT" rc %d error %d abortCode %d)\n",
          call, rc, call->error, call->abortCode));

    NETPRI;
    MUTEX_ENTER(&call->lock);

    if (rc == 0 && call->error == 0) {
        call->abortCode = 0;
        call->abortCount = 0;
    }

    call->arrivalProc = (void (*)())0;
    if (rc && call->error == 0) {
        rxi_CallError(call, rc);
        /* Send an abort message to the peer if this error code has
         * only just been set.  If it was set previously, assume the
         * peer has already been sent the error code or will request it 
         */
        rxi_SendCallAbort(call, (struct rx_packet *)0, 0, 0);
    }
    if (conn->type == RX_SERVER_CONNECTION) {
        /* Make sure reply or at least dummy reply is sent */
        if (call->mode == RX_MODE_RECEIVING) {
            rxi_WriteProc(call, 0, 0);
        }
        if (call->mode == RX_MODE_SENDING) {
            rxi_FlushWrite(call);
        }
        service = conn->service;
        rxi_calltrace(RX_CALL_END, call);
        /* Call goes to hold state until reply packets are acknowledged */
        if (call->tfirst + call->nSoftAcked < call->tnext) {
            call->state = RX_STATE_HOLD;
        } else {
            call->state = RX_STATE_DALLY;
            rxi_ClearTransmitQueue(call, 0);
            rxevent_Cancel(call->resendEvent, call, RX_CALL_REFCOUNT_RESEND);
            rxevent_Cancel(call->keepAliveEvent, call,
                           RX_CALL_REFCOUNT_ALIVE);
        }
    } else {                    /* Client connection */
        char dummy;
        /* Make sure server receives input packets, in the case where
         * no reply arguments are expected */
        if ((call->mode == RX_MODE_SENDING)
            || (call->mode == RX_MODE_RECEIVING && call->rnext == 1)) {
            (void)rxi_ReadProc(call, &dummy, 1);
        }

        /* If we had an outstanding delayed ack, be nice to the server
         * and force-send it now.
         */
        if (call->delayedAckEvent) {
            rxevent_Cancel(call->delayedAckEvent, call,
                           RX_CALL_REFCOUNT_DELAY);
            call->delayedAckEvent = NULL;
            rxi_SendDelayedAck(NULL, call, NULL);
        }

        /* We need to release the call lock since it's lower than the
         * conn_call_lock and we don't want to hold the conn_call_lock
         * over the rx_ReadProc call. The conn_call_lock needs to be held
         * here for the case where rx_NewCall is perusing the calls on
         * the connection structure. We don't want to signal until
         * rx_NewCall is in a stable state. Otherwise, rx_NewCall may
         * have checked this call, found it active and by the time it
         * goes to sleep, will have missed the signal.
         *
         * Do not clear the RX_CONN_MAKECALL_WAITING flag as long as
         * there are threads waiting to use the conn object.
         */
        MUTEX_EXIT(&call->lock);
        MUTEX_ENTER(&conn->conn_call_lock);
        MUTEX_ENTER(&call->lock);
        MUTEX_ENTER(&conn->conn_data_lock);
        conn->flags |= RX_CONN_BUSY;
        if (conn->flags & RX_CONN_MAKECALL_WAITING) {
            if (conn->makeCallWaiters == 0)
                conn->flags &= (~RX_CONN_MAKECALL_WAITING);
            MUTEX_EXIT(&conn->conn_data_lock);
#ifdef  RX_ENABLE_LOCKS
            CV_BROADCAST(&conn->conn_call_cv);
#else
            osi_rxWakeup(conn);
#endif
        }
#ifdef RX_ENABLE_LOCKS
        else {
            MUTEX_EXIT(&conn->conn_data_lock);
        }
#endif /* RX_ENABLE_LOCKS */
        call->state = RX_STATE_DALLY;
    }
    error = call->error;

    /* currentPacket, nLeft, and NFree must be zeroed here, because
     * ResetCall cannot: ResetCall may be called at splnet(), in the
     * kernel version, and may interrupt the macros rx_Read or
     * rx_Write, which run at normal priority for efficiency. */
    if (call->currentPacket) {
        call->currentPacket->flags &= ~RX_PKTFLAG_CP;
        rxi_FreePacket(call->currentPacket);
        call->currentPacket = (struct rx_packet *)0;
    }
        
    call->nLeft = call->nFree = call->curlen = 0;

    /* Free any packets from the last call to ReadvProc/WritevProc */
#ifdef RXDEBUG_PACKET
    call->iovqc -=
#endif /* RXDEBUG_PACKET */
        rxi_FreePackets(0, &call->iovq);

    CALL_RELE(call, RX_CALL_REFCOUNT_BEGIN);
    MUTEX_EXIT(&call->lock);
    if (conn->type == RX_CLIENT_CONNECTION) {
        MUTEX_EXIT(&conn->conn_call_lock);
        conn->flags &= ~RX_CONN_BUSY;
    }
    USERPRI;
    /*
     * Map errors to the local host's errno.h format.
     */
    error = ntoh_syserr_conv(error);
    return error;
}

#if !defined(KERNEL)

/* Call this routine when shutting down a server or client (especially
 * clients).  This will allow Rx to gracefully garbage collect server
 * connections, and reduce the number of retries that a server might
 * make to a dead client.
 * This is not quite right, since some calls may still be ongoing and
 * we can't lock them to destroy them. */
void
rx_Finalize(void)
{
    struct rx_connection **conn_ptr, **conn_end;

    INIT_PTHREAD_LOCKS;
    LOCK_RX_INIT;
    if (rxinit_status == 1) {
        UNLOCK_RX_INIT;
        return;                 /* Already shutdown. */
    }
    rxi_DeleteCachedConnections();
    if (rx_connHashTable) {
        MUTEX_ENTER(&rx_connHashTable_lock);
        for (conn_ptr = &rx_connHashTable[0], conn_end =
             &rx_connHashTable[rx_hashTableSize]; conn_ptr < conn_end;
             conn_ptr++) {
            struct rx_connection *conn, *next;
            for (conn = *conn_ptr; conn; conn = next) {
                next = conn->next;
                if (conn->type == RX_CLIENT_CONNECTION) {
                    /* MUTEX_ENTER(&conn->conn_data_lock); when used in kernel */
                    conn->refCount++;
                    /* MUTEX_EXIT(&conn->conn_data_lock); when used in kernel */
#ifdef RX_ENABLE_LOCKS
                    rxi_DestroyConnectionNoLock(conn);
#else /* RX_ENABLE_LOCKS */
                    rxi_DestroyConnection(conn);
#endif /* RX_ENABLE_LOCKS */
                }
            }
        }
#ifdef RX_ENABLE_LOCKS
        while (rx_connCleanup_list) {
            struct rx_connection *conn;
            conn = rx_connCleanup_list;
            rx_connCleanup_list = rx_connCleanup_list->next;
            MUTEX_EXIT(&rx_connHashTable_lock);
            rxi_CleanupConnection(conn);
            MUTEX_ENTER(&rx_connHashTable_lock);
        }
        MUTEX_EXIT(&rx_connHashTable_lock);
#endif /* RX_ENABLE_LOCKS */
    }
    rxi_flushtrace();

#ifdef AFS_NT40_ENV
    afs_winsockCleanup();
#endif

    rxinit_status = 1;
    UNLOCK_RX_INIT;
}
#endif

/* if we wakeup packet waiter too often, can get in loop with two
    AllocSendPackets each waking each other up (from ReclaimPacket calls) */
void
rxi_PacketsUnWait(void)
{
    if (!rx_waitingForPackets) {
        return;
    }
#ifdef KERNEL
    if (rxi_OverQuota(RX_PACKET_CLASS_SEND)) {
        return;                 /* still over quota */
    }
#endif /* KERNEL */
    rx_waitingForPackets = 0;
#ifdef  RX_ENABLE_LOCKS
    CV_BROADCAST(&rx_waitingForPackets_cv);
#else
    osi_rxWakeup(&rx_waitingForPackets);
#endif
    return;
}


/* ------------------Internal interfaces------------------------- */

/* Return this process's service structure for the
 * specified socket and service */
struct rx_service *
rxi_FindService(osi_socket socket, u_short serviceId)
{
    struct rx_service **sp;
    for (sp = &rx_services[0]; *sp; sp++) {
        if ((*sp)->serviceId == serviceId && (*sp)->socket == socket)
            return *sp;
    }
    return 0;
}

#ifdef RXDEBUG_PACKET
#ifdef KDUMP_RX_LOCK
static struct rx_call_rx_lock *rx_allCallsp = 0;
#else
static struct rx_call *rx_allCallsp = 0;
#endif
#endif /* RXDEBUG_PACKET */

/* Allocate a call structure, for the indicated channel of the
 * supplied connection.  The mode and state of the call must be set by
 * the caller. Returns the call with mutex locked. */
struct rx_call *
rxi_NewCall(struct rx_connection *conn, int channel)
{
    struct rx_call *call;
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
    struct rx_call *cp; /* Call pointer temp */
    struct rx_call *nxp;        /* Next call pointer, for queue_Scan */
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */

    dpf(("rxi_NewCall(conn %"AFS_PTR_FMT", channel %d)\n", conn, channel));

    /* Grab an existing call structure, or allocate a new one.
     * Existing call structures are assumed to have been left reset by
     * rxi_FreeCall */
    MUTEX_ENTER(&rx_freeCallQueue_lock);

#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
    /*
     * EXCEPT that the TQ might not yet be cleared out.
     * Skip over those with in-use TQs.
     */
    call = NULL;
    for (queue_Scan(&rx_freeCallQueue, cp, nxp, rx_call)) {
        if (!(cp->flags & RX_CALL_TQ_BUSY)) {
            call = cp;
            break;
        }
    }
    if (call) {
#else /* AFS_GLOBAL_RXLOCK_KERNEL */
    if (queue_IsNotEmpty(&rx_freeCallQueue)) {
        call = queue_First(&rx_freeCallQueue, rx_call);
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
        queue_Remove(call);
        if (rx_stats_active)
            rx_MutexDecrement(rx_stats.nFreeCallStructs, rx_stats_mutex);
        MUTEX_EXIT(&rx_freeCallQueue_lock);
        MUTEX_ENTER(&call->lock);
        CLEAR_CALL_QUEUE_LOCK(call);
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
        /* Now, if TQ wasn't cleared earlier, do it now. */
        rxi_WaitforTQBusy(call);
        if (call->flags & RX_CALL_TQ_CLEARME) {
            rxi_ClearTransmitQueue(call, 1);
            /*queue_Init(&call->tq);*/
        }
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
        /* Bind the call to its connection structure */
        call->conn = conn;
        rxi_ResetCall(call, 1);
    } else {

        call = (struct rx_call *)rxi_Alloc(sizeof(struct rx_call));
#ifdef RXDEBUG_PACKET
        call->allNextp = rx_allCallsp;
        rx_allCallsp = call;
        call->call_id = 
#endif /* RXDEBUG_PACKET */
            rx_MutexIncrement(rx_stats.nCallStructs, rx_stats_mutex);
        
        MUTEX_EXIT(&rx_freeCallQueue_lock);
        MUTEX_INIT(&call->lock, "call lock", MUTEX_DEFAULT, NULL);
        MUTEX_ENTER(&call->lock);
        CV_INIT(&call->cv_twind, "call twind", CV_DEFAULT, 0);
        CV_INIT(&call->cv_rq, "call rq", CV_DEFAULT, 0);
        CV_INIT(&call->cv_tq, "call tq", CV_DEFAULT, 0);

        /* Initialize once-only items */
        queue_Init(&call->tq);
        queue_Init(&call->rq);
        queue_Init(&call->iovq);
#ifdef RXDEBUG_PACKET
        call->rqc = call->tqc = call->iovqc = 0;
#endif /* RXDEBUG_PACKET */
        /* Bind the call to its connection structure (prereq for reset) */
        call->conn = conn;
        rxi_ResetCall(call, 1);
    }
    call->channel = channel;
    call->callNumber = &conn->callNumber[channel];
    call->rwind = conn->rwind[channel];
    call->twind = conn->twind[channel];
    /* Note that the next expected call number is retained (in
     * conn->callNumber[i]), even if we reallocate the call structure
     */
    conn->call[channel] = call;
    /* if the channel's never been used (== 0), we should start at 1, otherwise
     * the call number is valid from the last time this channel was used */
    if (*call->callNumber == 0)
        *call->callNumber = 1;

    return call;
}

/* A call has been inactive long enough that so we can throw away
 * state, including the call structure, which is placed on the call
 * free list.
 * Call is locked upon entry.
 * haveCTLock set if called from rxi_ReapConnections
 */
#ifdef RX_ENABLE_LOCKS
void
rxi_FreeCall(struct rx_call *call, int haveCTLock)
#else /* RX_ENABLE_LOCKS */
void
rxi_FreeCall(struct rx_call *call)
#endif                          /* RX_ENABLE_LOCKS */
{
    int channel = call->channel;
    struct rx_connection *conn = call->conn;


    if (call->state == RX_STATE_DALLY || call->state == RX_STATE_HOLD)
        (*call->callNumber)++;
    rxi_ResetCall(call, 0);
    call->conn->call[channel] = (struct rx_call *)0;

    MUTEX_ENTER(&rx_freeCallQueue_lock);
    SET_CALL_QUEUE_LOCK(call, &rx_freeCallQueue_lock);
#ifdef AFS_GLOBAL_RXLOCK_KERNEL
    /* A call may be free even though its transmit queue is still in use.
     * Since we search the call list from head to tail, put busy calls at
     * the head of the list, and idle calls at the tail.
     */
    if (call->flags & RX_CALL_TQ_BUSY)
        queue_Prepend(&rx_freeCallQueue, call);
    else
        queue_Append(&rx_freeCallQueue, call);
#else /* AFS_GLOBAL_RXLOCK_KERNEL */
    queue_Append(&rx_freeCallQueue, call);
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
    if (rx_stats_active)
        rx_MutexIncrement(rx_stats.nFreeCallStructs, rx_stats_mutex);
    MUTEX_EXIT(&rx_freeCallQueue_lock);

    /* Destroy the connection if it was previously slated for
     * destruction, i.e. the Rx client code previously called
     * rx_DestroyConnection (client connections), or
     * rxi_ReapConnections called the same routine (server
     * connections).  Only do this, however, if there are no
     * outstanding calls. Note that for fine grain locking, there appears
     * to be a deadlock in that rxi_FreeCall has a call locked and
     * DestroyConnectionNoLock locks each call in the conn. But note a
     * few lines up where we have removed this call from the conn.
     * If someone else destroys a connection, they either have no
     * call lock held or are going through this section of code.
     */
    if (conn->flags & RX_CONN_DESTROY_ME && !(conn->flags & RX_CONN_MAKECALL_WAITING)) {
        MUTEX_ENTER(&conn->conn_data_lock);
        conn->refCount++;
        MUTEX_EXIT(&conn->conn_data_lock);
#ifdef RX_ENABLE_LOCKS
        if (haveCTLock)
            rxi_DestroyConnectionNoLock(conn);
        else
            rxi_DestroyConnection(conn);
#else /* RX_ENABLE_LOCKS */
        rxi_DestroyConnection(conn);
#endif /* RX_ENABLE_LOCKS */
    }
}

afs_int32 rxi_Alloccnt = 0, rxi_Allocsize = 0;
char *
rxi_Alloc(size_t size)
{
    char *p;

    if (rx_stats_active)
        rx_MutexAdd1Increment2(rxi_Allocsize, (afs_int32)size, rxi_Alloccnt, rx_stats_mutex);

p = (char *)
#if defined(KERNEL) && !defined(UKERNEL) && defined(AFS_FBSD80_ENV)
  afs_osi_Alloc_NoSleep(size);
#else
  osi_Alloc(size);
#endif
    if (!p)
        osi_Panic("rxi_Alloc error");
    memset(p, 0, size);
    return p;
}

void
rxi_Free(void *addr, size_t size)
{
    if (rx_stats_active)
        rx_MutexAdd1Decrement2(rxi_Allocsize, -(afs_int32)size, rxi_Alloccnt, rx_stats_mutex);
    osi_Free(addr, size);
}

void 
rxi_SetPeerMtu(afs_uint32 host, afs_uint32 port, int mtu)
{
    struct rx_peer **peer_ptr, **peer_end;
    int hashIndex;

    MUTEX_ENTER(&rx_peerHashTable_lock);
    if (port == 0) {
       for (peer_ptr = &rx_peerHashTable[0], peer_end =
                &rx_peerHashTable[rx_hashTableSize]; peer_ptr < peer_end;
            peer_ptr++) {
           struct rx_peer *peer, *next;
           for (peer = *peer_ptr; peer; peer = next) {
               next = peer->next;
               if (host == peer->host) {
                   MUTEX_ENTER(&peer->peer_lock);
                   peer->ifMTU=MIN(mtu, peer->ifMTU);
                   peer->natMTU = rxi_AdjustIfMTU(peer->ifMTU);
                   MUTEX_EXIT(&peer->peer_lock);
               }
           }
       }
    } else {
       struct rx_peer *peer;
       hashIndex = PEER_HASH(host, port);
       for (peer = rx_peerHashTable[hashIndex]; peer; peer = peer->next) {
           if ((peer->host == host) && (peer->port == port)) {
               MUTEX_ENTER(&peer->peer_lock);
               peer->ifMTU=MIN(mtu, peer->ifMTU);
               peer->natMTU = rxi_AdjustIfMTU(peer->ifMTU);
               MUTEX_EXIT(&peer->peer_lock);
           }
       }
    }
    MUTEX_EXIT(&rx_peerHashTable_lock);
}

/* Find the peer process represented by the supplied (host,port)
 * combination.  If there is no appropriate active peer structure, a
 * new one will be allocated and initialized 
 * The origPeer, if set, is a pointer to a peer structure on which the
 * refcount will be be decremented. This is used to replace the peer
 * structure hanging off a connection structure */
struct rx_peer *
rxi_FindPeer(afs_uint32 host, u_short port,
             struct rx_peer *origPeer, int create)
{
    struct rx_peer *pp;
    int hashIndex;
    hashIndex = PEER_HASH(host, port);
    MUTEX_ENTER(&rx_peerHashTable_lock);
    for (pp = rx_peerHashTable[hashIndex]; pp; pp = pp->next) {
        if ((pp->host == host) && (pp->port == port))
            break;
    }
    if (!pp) {
        if (create) {
            pp = rxi_AllocPeer();       /* This bzero's *pp */
            pp->host = host;    /* set here or in InitPeerParams is zero */
            pp->port = port;
            MUTEX_INIT(&pp->peer_lock, "peer_lock", MUTEX_DEFAULT, 0);
            queue_Init(&pp->congestionQueue);
            queue_Init(&pp->rpcStats);
            pp->next = rx_peerHashTable[hashIndex];
            rx_peerHashTable[hashIndex] = pp;
            rxi_InitPeerParams(pp);
            if (rx_stats_active)
                rx_MutexIncrement(rx_stats.nPeerStructs, rx_stats_mutex);
        }
    }
    if (pp && create) {
        pp->refCount++;
    }
    if (origPeer)
        origPeer->refCount--;
    MUTEX_EXIT(&rx_peerHashTable_lock);
    return pp;
}


/* Find the connection at (host, port) started at epoch, and with the
 * given connection id.  Creates the server connection if necessary.
 * The type specifies whether a client connection or a server
 * connection is desired.  In both cases, (host, port) specify the
 * peer's (host, pair) pair.  Client connections are not made
 * automatically by this routine.  The parameter socket gives the
 * socket descriptor on which the packet was received.  This is used,
 * in the case of server connections, to check that *new* connections
 * come via a valid (port, serviceId).  Finally, the securityIndex
 * parameter must match the existing index for the connection.  If a
 * server connection is created, it will be created using the supplied
 * index, if the index is valid for this service */
struct rx_connection *
rxi_FindConnection(osi_socket socket, afs_int32 host,
                   u_short port, u_short serviceId, afs_uint32 cid,
                   afs_uint32 epoch, int type, u_int securityIndex)
{
    int hashindex, flag, i;
    struct rx_connection *conn;
    hashindex = CONN_HASH(host, port, cid, epoch, type);
    MUTEX_ENTER(&rx_connHashTable_lock);
    rxLastConn ? (conn = rxLastConn, flag = 0) : (conn =
                                                  rx_connHashTable[hashindex],
                                                  flag = 1);
    for (; conn;) {
        if ((conn->type == type) && ((cid & RX_CIDMASK) == conn->cid)
            && (epoch == conn->epoch)) {
            struct rx_peer *pp = conn->peer;
            if (securityIndex != conn->securityIndex) {
                /* this isn't supposed to happen, but someone could forge a packet
                 * like this, and there seems to be some CM bug that makes this
                 * happen from time to time -- in which case, the fileserver
                 * asserts. */
                MUTEX_EXIT(&rx_connHashTable_lock);
                return (struct rx_connection *)0;
            }
            if (pp->host == host && pp->port == port)
                break;
            if (type == RX_CLIENT_CONNECTION && pp->port == port)
                break;
            /* So what happens when it's a callback connection? */
            if (                /*type == RX_CLIENT_CONNECTION && */
                   (conn->epoch & 0x80000000))
                break;
        }
        if (!flag) {
            /* the connection rxLastConn that was used the last time is not the
             ** one we are looking for now. Hence, start searching in the hash */
            flag = 1;
            conn = rx_connHashTable[hashindex];
        } else
            conn = conn->next;
    }
    if (!conn) {
        struct rx_service *service;
        if (type == RX_CLIENT_CONNECTION) {
            MUTEX_EXIT(&rx_connHashTable_lock);
            return (struct rx_connection *)0;
        }
        service = rxi_FindService(socket, serviceId);
        if (!service || (securityIndex >= service->nSecurityObjects)
            || (service->securityObjects[securityIndex] == 0)) {
            MUTEX_EXIT(&rx_connHashTable_lock);
            return (struct rx_connection *)0;
        }
        conn = rxi_AllocConnection();   /* This bzero's the connection */
        MUTEX_INIT(&conn->conn_call_lock, "conn call lock", MUTEX_DEFAULT, 0);
        MUTEX_INIT(&conn->conn_data_lock, "conn data lock", MUTEX_DEFAULT, 0);
        CV_INIT(&conn->conn_call_cv, "conn call cv", CV_DEFAULT, 0);
        conn->next = rx_connHashTable[hashindex];
        rx_connHashTable[hashindex] = conn;
        conn->peer = rxi_FindPeer(host, port, 0, 1);
        conn->type = RX_SERVER_CONNECTION;
        conn->lastSendTime = clock_Sec();       /* don't GC immediately */
        conn->epoch = epoch;
        conn->cid = cid & RX_CIDMASK;
        /* conn->serial = conn->lastSerial = 0; */
        /* conn->timeout = 0; */
        conn->ackRate = RX_FAST_ACK_RATE;
        conn->service = service;
        conn->serviceId = serviceId;
        conn->securityIndex = securityIndex;
        conn->securityObject = service->securityObjects[securityIndex];
        conn->nSpecific = 0;
        conn->specific = NULL;
        rx_SetConnDeadTime(conn, service->connDeadTime);
        rx_SetConnIdleDeadTime(conn, service->idleDeadTime);
        rx_SetServerConnIdleDeadErr(conn, service->idleDeadErr);
        for (i = 0; i < RX_MAXCALLS; i++) {
            conn->twind[i] = rx_initSendWindow;
            conn->rwind[i] = rx_initReceiveWindow;
        }
        /* Notify security object of the new connection */
        RXS_NewConnection(conn->securityObject, conn);
        /* XXXX Connection timeout? */
        if (service->newConnProc)
            (*service->newConnProc) (conn);
        if (rx_stats_active)
            rx_MutexIncrement(rx_stats.nServerConns, rx_stats_mutex);
    }

    MUTEX_ENTER(&conn->conn_data_lock);
    conn->refCount++;
    MUTEX_EXIT(&conn->conn_data_lock);

    rxLastConn = conn;          /* store this connection as the last conn used */
    MUTEX_EXIT(&rx_connHashTable_lock);
    return conn;
}

/* There are two packet tracing routines available for testing and monitoring
 * Rx.  One is called just after every packet is received and the other is
 * called just before every packet is sent.  Received packets, have had their
 * headers decoded, and packets to be sent have not yet had their headers
 * encoded.  Both take two parameters: a pointer to the packet and a sockaddr
 * containing the network address.  Both can be modified.  The return value, if
 * non-zero, indicates that the packet should be dropped.  */

int (*rx_justReceived) (struct rx_packet *, struct sockaddr_in *) = 0;
int (*rx_almostSent) (struct rx_packet *, struct sockaddr_in *) = 0;

/* A packet has been received off the interface.  Np is the packet, socket is
 * the socket number it was received from (useful in determining which service
 * this packet corresponds to), and (host, port) reflect the host,port of the
 * sender.  This call returns the packet to the caller if it is finished with
 * it, rather than de-allocating it, just as a small performance hack */

struct rx_packet *
rxi_ReceivePacket(struct rx_packet *np, osi_socket socket,
                  afs_uint32 host, u_short port, int *tnop,
                  struct rx_call **newcallp)
{
    struct rx_call *call;
    struct rx_connection *conn;
    int channel;
    afs_uint32 currentCallNumber;
    int type;
    int skew;
#ifdef RXDEBUG
    char *packetType;
#endif
    struct rx_packet *tnp;

#ifdef RXDEBUG
/* We don't print out the packet until now because (1) the time may not be
 * accurate enough until now in the lwp implementation (rx_Listener only gets
 * the time after the packet is read) and (2) from a protocol point of view,
 * this is the first time the packet has been seen */
    packetType = (np->header.type > 0 && np->header.type < RX_N_PACKET_TYPES)
        ? rx_packetTypes[np->header.type - 1] : "*UNKNOWN*";
    dpf(("R %d %s: %x.%d.%d.%d.%d.%d.%d flags %d, packet %"AFS_PTR_FMT,
         np->header.serial, packetType, ntohl(host), ntohs(port), np->header.serviceId,
         np->header.epoch, np->header.cid, np->header.callNumber,
         np->header.seq, np->header.flags, np));
#endif

    if (np->header.type == RX_PACKET_TYPE_VERSION) {
        return rxi_ReceiveVersionPacket(np, socket, host, port, 1);
    }

    if (np->header.type == RX_PACKET_TYPE_DEBUG) {
        return rxi_ReceiveDebugPacket(np, socket, host, port, 1);
    }
#ifdef RXDEBUG
    /* If an input tracer function is defined, call it with the packet and
     * network address.  Note this function may modify its arguments. */
    if (rx_justReceived) {
        struct sockaddr_in addr;
        int drop;
        addr.sin_family = AF_INET;
        addr.sin_port = port;
        addr.sin_addr.s_addr = host;
#ifdef STRUCT_SOCKADDR_HAS_SA_LEN
        addr.sin_len = sizeof(addr);
#endif /* AFS_OSF_ENV */
        drop = (*rx_justReceived) (np, &addr);
        /* drop packet if return value is non-zero */
        if (drop)
            return np;
        port = addr.sin_port;   /* in case fcn changed addr */
        host = addr.sin_addr.s_addr;
    }
#endif

    /* If packet was not sent by the client, then *we* must be the client */
    type = ((np->header.flags & RX_CLIENT_INITIATED) != RX_CLIENT_INITIATED)
        ? RX_CLIENT_CONNECTION : RX_SERVER_CONNECTION;

    /* Find the connection (or fabricate one, if we're the server & if
     * necessary) associated with this packet */
    conn =
        rxi_FindConnection(socket, host, port, np->header.serviceId,
                           np->header.cid, np->header.epoch, type,
                           np->header.securityIndex);

    if (!conn) {
        /* If no connection found or fabricated, just ignore the packet.
         * (An argument could be made for sending an abort packet for
         * the conn) */
        return np;
    }

    MUTEX_ENTER(&conn->conn_data_lock);
    if (conn->maxSerial < np->header.serial)
        conn->maxSerial = np->header.serial;
    MUTEX_EXIT(&conn->conn_data_lock);

    /* If the connection is in an error state, send an abort packet and ignore
     * the incoming packet */
    if (conn->error) {
        /* Don't respond to an abort packet--we don't want loops! */
        MUTEX_ENTER(&conn->conn_data_lock);
        if (np->header.type != RX_PACKET_TYPE_ABORT)
            np = rxi_SendConnectionAbort(conn, np, 1, 0);
        conn->refCount--;
        MUTEX_EXIT(&conn->conn_data_lock);
        return np;
    }

    /* Check for connection-only requests (i.e. not call specific). */
    if (np->header.callNumber == 0) {
        switch (np->header.type) {
        case RX_PACKET_TYPE_ABORT: {
            /* What if the supplied error is zero? */
            afs_int32 errcode = ntohl(rx_GetInt32(np, 0));
            dpf(("rxi_ReceivePacket ABORT rx_GetInt32 = %d", errcode));
            rxi_ConnectionError(conn, errcode);
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return np;
        }
        case RX_PACKET_TYPE_CHALLENGE:
            tnp = rxi_ReceiveChallengePacket(conn, np, 1);
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return tnp;
        case RX_PACKET_TYPE_RESPONSE:
            tnp = rxi_ReceiveResponsePacket(conn, np, 1);
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return tnp;
        case RX_PACKET_TYPE_PARAMS:
        case RX_PACKET_TYPE_PARAMS + 1:
        case RX_PACKET_TYPE_PARAMS + 2:
            /* ignore these packet types for now */
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return np;


        default:
            /* Should not reach here, unless the peer is broken: send an
             * abort packet */
            rxi_ConnectionError(conn, RX_PROTOCOL_ERROR);
            MUTEX_ENTER(&conn->conn_data_lock);
            tnp = rxi_SendConnectionAbort(conn, np, 1, 0);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return tnp;
        }
    }

    channel = np->header.cid & RX_CHANNELMASK;
    call = conn->call[channel];
#ifdef  RX_ENABLE_LOCKS
    if (call)
        MUTEX_ENTER(&call->lock);
    /* Test to see if call struct is still attached to conn. */
    if (call != conn->call[channel]) {
        if (call)
            MUTEX_EXIT(&call->lock);
        if (type == RX_SERVER_CONNECTION) {
            call = conn->call[channel];
            /* If we started with no call attached and there is one now,
             * another thread is also running this routine and has gotten
             * the connection channel. We should drop this packet in the tests
             * below. If there was a call on this connection and it's now
             * gone, then we'll be making a new call below.
             * If there was previously a call and it's now different then
             * the old call was freed and another thread running this routine
             * has created a call on this channel. One of these two threads
             * has a packet for the old call and the code below handles those
             * cases.
             */
            if (call)
                MUTEX_ENTER(&call->lock);
        } else {
            /* This packet can't be for this call. If the new call address is
             * 0 then no call is running on this channel. If there is a call
             * then, since this is a client connection we're getting data for
             * it must be for the previous call.
             */
            if (rx_stats_active)
                rx_MutexIncrement(rx_stats.spuriousPacketsRead, rx_stats_mutex);
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return np;
        }
    }
#endif
    currentCallNumber = conn->callNumber[channel];

    if (type == RX_SERVER_CONNECTION) { /* We're the server */
        if (np->header.callNumber < currentCallNumber) {
            if (rx_stats_active)
                rx_MutexIncrement(rx_stats.spuriousPacketsRead, rx_stats_mutex);
#ifdef  RX_ENABLE_LOCKS
            if (call)
                MUTEX_EXIT(&call->lock);
#endif
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return np;
        }
        if (!call) {
            MUTEX_ENTER(&conn->conn_call_lock);
            call = rxi_NewCall(conn, channel);
            MUTEX_EXIT(&conn->conn_call_lock);
            *call->callNumber = np->header.callNumber;
#ifdef RXDEBUG
            if (np->header.callNumber == 0) 
                dpf(("RecPacket call 0 %d %s: %x.%u.%u.%u.%u.%u.%u flags %d, packet %"AFS_PTR_FMT" resend %d.%.06d len %d",
                      np->header.serial, rx_packetTypes[np->header.type - 1], ntohl(conn->peer->host), ntohs(conn->peer->port),
                      np->header.serial, np->header.epoch, np->header.cid, np->header.callNumber, np->header.seq,
                      np->header.flags, np, np->retryTime.sec, np->retryTime.usec / 1000, np->length));
#endif
            call->state = RX_STATE_PRECALL;
            clock_GetTime(&call->queueTime);
            hzero(call->bytesSent);
            hzero(call->bytesRcvd);
            /*
             * If the number of queued calls exceeds the overload
             * threshold then abort this call.
             */
            if ((rx_BusyThreshold > 0) && (rx_nWaiting > rx_BusyThreshold)) {
                struct rx_packet *tp;
                
                rxi_CallError(call, rx_BusyError);
                tp = rxi_SendCallAbort(call, np, 1, 0);
                MUTEX_EXIT(&call->lock);
                MUTEX_ENTER(&conn->conn_data_lock);
                conn->refCount--;
                MUTEX_EXIT(&conn->conn_data_lock);
                if (rx_stats_active)
                    rx_MutexIncrement(rx_stats.nBusies, rx_stats_mutex);
                return tp;
            }
            rxi_KeepAliveOn(call);
        } else if (np->header.callNumber != currentCallNumber) {
            /* Wait until the transmit queue is idle before deciding
             * whether to reset the current call. Chances are that the
             * call will be in ether DALLY or HOLD state once the TQ_BUSY
             * flag is cleared.
             */
#ifdef AFS_GLOBAL_RXLOCK_KERNEL
            while ((call->state == RX_STATE_ACTIVE)
                   && (call->flags & RX_CALL_TQ_BUSY)) {
                call->flags |= RX_CALL_TQ_WAIT;
                call->tqWaiters++;
#ifdef RX_ENABLE_LOCKS
                osirx_AssertMine(&call->lock, "rxi_Start lock3");
                CV_WAIT(&call->cv_tq, &call->lock);
#else /* RX_ENABLE_LOCKS */
                osi_rxSleep(&call->tq);
#endif /* RX_ENABLE_LOCKS */
                call->tqWaiters--;
                if (call->tqWaiters == 0)
                    call->flags &= ~RX_CALL_TQ_WAIT;
            }
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
            /* If the new call cannot be taken right now send a busy and set
             * the error condition in this call, so that it terminates as
             * quickly as possible */
            if (call->state == RX_STATE_ACTIVE) {
                struct rx_packet *tp;

                rxi_CallError(call, RX_CALL_DEAD);
                tp = rxi_SendSpecial(call, conn, np, RX_PACKET_TYPE_BUSY,
                                     NULL, 0, 1);
                MUTEX_EXIT(&call->lock);
                MUTEX_ENTER(&conn->conn_data_lock);
                conn->refCount--;
                MUTEX_EXIT(&conn->conn_data_lock);
                return tp;
            }
            rxi_ResetCall(call, 0);
            *call->callNumber = np->header.callNumber;
#ifdef RXDEBUG
            if (np->header.callNumber == 0) 
                dpf(("RecPacket call 0 %d %s: %x.%u.%u.%u.%u.%u.%u flags %d, packet %"AFS_PTR_FMT" resend %d.%06d len %d",
                      np->header.serial, rx_packetTypes[np->header.type - 1], ntohl(conn->peer->host), ntohs(conn->peer->port),
                      np->header.serial, np->header.epoch, np->header.cid, np->header.callNumber, np->header.seq,
                      np->header.flags, np, np->retryTime.sec, np->retryTime.usec, np->length));
#endif
            call->state = RX_STATE_PRECALL;
            clock_GetTime(&call->queueTime);
            hzero(call->bytesSent);
            hzero(call->bytesRcvd);
            /*
             * If the number of queued calls exceeds the overload
             * threshold then abort this call.
             */
            if ((rx_BusyThreshold > 0) && (rx_nWaiting > rx_BusyThreshold)) {
                struct rx_packet *tp;

                rxi_CallError(call, rx_BusyError);
                tp = rxi_SendCallAbort(call, np, 1, 0);
                MUTEX_EXIT(&call->lock);
                MUTEX_ENTER(&conn->conn_data_lock);
                conn->refCount--;
                MUTEX_EXIT(&conn->conn_data_lock);
                if (rx_stats_active)
                    rx_MutexIncrement(rx_stats.nBusies, rx_stats_mutex);
                return tp;
            }
            rxi_KeepAliveOn(call);
        } else {
            /* Continuing call; do nothing here. */
        }
    } else {                    /* we're the client */
        /* Ignore all incoming acknowledgements for calls in DALLY state */
        if (call && (call->state == RX_STATE_DALLY)
            && (np->header.type == RX_PACKET_TYPE_ACK)) {
            if (rx_stats_active)
                rx_MutexIncrement(rx_stats.ignorePacketDally, rx_stats_mutex);
#ifdef  RX_ENABLE_LOCKS
            if (call) {
                MUTEX_EXIT(&call->lock);
            }
#endif
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return np;
        }

        /* Ignore anything that's not relevant to the current call.  If there
         * isn't a current call, then no packet is relevant. */
        if (!call || (np->header.callNumber != currentCallNumber)) {
            if (rx_stats_active)
                rx_MutexIncrement(rx_stats.spuriousPacketsRead, rx_stats_mutex);
#ifdef  RX_ENABLE_LOCKS
            if (call) {
                MUTEX_EXIT(&call->lock);
            }
#endif
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return np;
        }
        /* If the service security object index stamped in the packet does not
         * match the connection's security index, ignore the packet */
        if (np->header.securityIndex != conn->securityIndex) {
#ifdef  RX_ENABLE_LOCKS
            MUTEX_EXIT(&call->lock);
#endif
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return np;
        }

        /* If we're receiving the response, then all transmit packets are
         * implicitly acknowledged.  Get rid of them. */
        if (np->header.type == RX_PACKET_TYPE_DATA) {
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
            /* XXX Hack. Because we must release the global rx lock when
             * sending packets (osi_NetSend) we drop all acks while we're
             * traversing the tq in rxi_Start sending packets out because
             * packets may move to the freePacketQueue as result of being here!
             * So we drop these packets until we're safely out of the
             * traversing. Really ugly! 
             * For fine grain RX locking, we set the acked field in the
             * packets and let rxi_Start remove them from the transmit queue.
             */
            if (call->flags & RX_CALL_TQ_BUSY) {
#ifdef  RX_ENABLE_LOCKS
                rxi_SetAcksInTransmitQueue(call);
#else
                conn->refCount--;
                return np;      /* xmitting; drop packet */
#endif
            } else {
                rxi_ClearTransmitQueue(call, 0);
            }
#else /* AFS_GLOBAL_RXLOCK_KERNEL */
            rxi_ClearTransmitQueue(call, 0);
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
        } else {
            if (np->header.type == RX_PACKET_TYPE_ACK) {
                /* now check to see if this is an ack packet acknowledging that the
                 * server actually *lost* some hard-acked data.  If this happens we
                 * ignore this packet, as it may indicate that the server restarted in
                 * the middle of a call.  It is also possible that this is an old ack
                 * packet.  We don't abort the connection in this case, because this
                 * *might* just be an old ack packet.  The right way to detect a server
                 * restart in the midst of a call is to notice that the server epoch
                 * changed, btw.  */
                /* XXX I'm not sure this is exactly right, since tfirst **IS**
                 * XXX unacknowledged.  I think that this is off-by-one, but
                 * XXX I don't dare change it just yet, since it will
                 * XXX interact badly with the server-restart detection 
                 * XXX code in receiveackpacket.  */
                if (ntohl(rx_GetInt32(np, FIRSTACKOFFSET)) < call->tfirst) {
                    if (rx_stats_active)
                        rx_MutexIncrement(rx_stats.spuriousPacketsRead, rx_stats_mutex);
                    MUTEX_EXIT(&call->lock);
                    MUTEX_ENTER(&conn->conn_data_lock);
                    conn->refCount--;
                    MUTEX_EXIT(&conn->conn_data_lock);
                    return np;
                }
            }
        }                       /* else not a data packet */
    }

    osirx_AssertMine(&call->lock, "rxi_ReceivePacket middle");
    /* Set remote user defined status from packet */
    call->remoteStatus = np->header.userStatus;

    /* Note the gap between the expected next packet and the actual
     * packet that arrived, when the new packet has a smaller serial number
     * than expected.  Rioses frequently reorder packets all by themselves,
     * so this will be quite important with very large window sizes.
     * Skew is checked against 0 here to avoid any dependence on the type of
     * inPacketSkew (which may be unsigned).  In C, -1 > (unsigned) 0 is always
     * true! 
     * The inPacketSkew should be a smoothed running value, not just a maximum.  MTUXXX
     * see CalculateRoundTripTime for an example of how to keep smoothed values.
     * I think using a beta of 1/8 is probably appropriate.  93.04.21
     */
    MUTEX_ENTER(&conn->conn_data_lock);
    skew = conn->lastSerial - np->header.serial;
    conn->lastSerial = np->header.serial;
    MUTEX_EXIT(&conn->conn_data_lock);
    if (skew > 0) {
        struct rx_peer *peer;
        peer = conn->peer;
        if (skew > peer->inPacketSkew) {
            dpf(("*** In skew changed from %d to %d\n",
                  peer->inPacketSkew, skew));
            peer->inPacketSkew = skew;
        }
    }

    /* Now do packet type-specific processing */
    switch (np->header.type) {
    case RX_PACKET_TYPE_DATA:
        np = rxi_ReceiveDataPacket(call, np, 1, socket, host, port, tnop,
                                   newcallp);
        break;
    case RX_PACKET_TYPE_ACK:
        /* Respond immediately to ack packets requesting acknowledgement
         * (ping packets) */
        if (np->header.flags & RX_REQUEST_ACK) {
            if (call->error)
                (void)rxi_SendCallAbort(call, 0, 1, 0);
            else
                (void)rxi_SendAck(call, 0, np->header.serial,
                                  RX_ACK_PING_RESPONSE, 1);
        }
        np = rxi_ReceiveAckPacket(call, np, 1);
        break;
    case RX_PACKET_TYPE_ABORT: {
        /* An abort packet: reset the call, passing the error up to the user. */
        /* What if error is zero? */
        /* What if the error is -1? the application will treat it as a timeout. */
        afs_int32 errdata = ntohl(*(afs_int32 *) rx_DataOf(np));
        dpf(("rxi_ReceivePacket ABORT rx_DataOf = %d", errdata));
        rxi_CallError(call, errdata);
        MUTEX_EXIT(&call->lock);
        MUTEX_ENTER(&conn->conn_data_lock);
        conn->refCount--;
        MUTEX_EXIT(&conn->conn_data_lock);
        return np;              /* xmitting; drop packet */
    }
    case RX_PACKET_TYPE_BUSY:
        /* XXXX */
        break;
    case RX_PACKET_TYPE_ACKALL:
        /* All packets acknowledged, so we can drop all packets previously
         * readied for sending */
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
        /* XXX Hack. We because we can't release the global rx lock when
         * sending packets (osi_NetSend) we drop all ack pkts while we're
         * traversing the tq in rxi_Start sending packets out because
         * packets may move to the freePacketQueue as result of being
         * here! So we drop these packets until we're safely out of the
         * traversing. Really ugly! 
         * For fine grain RX locking, we set the acked field in the packets
         * and let rxi_Start remove the packets from the transmit queue.
         */
        if (call->flags & RX_CALL_TQ_BUSY) {
#ifdef  RX_ENABLE_LOCKS
            rxi_SetAcksInTransmitQueue(call);
            break;
#else /* RX_ENABLE_LOCKS */
            MUTEX_EXIT(&call->lock);
            MUTEX_ENTER(&conn->conn_data_lock);
            conn->refCount--;
            MUTEX_EXIT(&conn->conn_data_lock);
            return np;          /* xmitting; drop packet */
#endif /* RX_ENABLE_LOCKS */
        }
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
        rxi_ClearTransmitQueue(call, 0);
        rxevent_Cancel(call->keepAliveEvent, call, RX_CALL_REFCOUNT_ALIVE);
        break;
    default:
        /* Should not reach here, unless the peer is broken: send an abort
         * packet */
        rxi_CallError(call, RX_PROTOCOL_ERROR);
        np = rxi_SendCallAbort(call, np, 1, 0);
        break;
    };
    /* Note when this last legitimate packet was received, for keep-alive
     * processing.  Note, we delay getting the time until now in the hope that
     * the packet will be delivered to the user before any get time is required
     * (if not, then the time won't actually be re-evaluated here). */
    call->lastReceiveTime = clock_Sec();
    MUTEX_EXIT(&call->lock);
    MUTEX_ENTER(&conn->conn_data_lock);
    conn->refCount--;
    MUTEX_EXIT(&conn->conn_data_lock);
    return np;
}

/* return true if this is an "interesting" connection from the point of view
    of someone trying to debug the system */
int
rxi_IsConnInteresting(struct rx_connection *aconn)
{
    int i;
    struct rx_call *tcall;

    if (aconn->flags & (RX_CONN_MAKECALL_WAITING | RX_CONN_DESTROY_ME))
        return 1;
    for (i = 0; i < RX_MAXCALLS; i++) {
        tcall = aconn->call[i];
        if (tcall) {
            if ((tcall->state == RX_STATE_PRECALL)
                || (tcall->state == RX_STATE_ACTIVE))
                return 1;
            if ((tcall->mode == RX_MODE_SENDING)
                || (tcall->mode == RX_MODE_RECEIVING))
                return 1;
        }
    }
    return 0;
}

#ifdef KERNEL
/* if this is one of the last few packets AND it wouldn't be used by the
   receiving call to immediately satisfy a read request, then drop it on
   the floor, since accepting it might prevent a lock-holding thread from
   making progress in its reading. If a call has been cleared while in
   the precall state then ignore all subsequent packets until the call
   is assigned to a thread. */

static int
TooLow(struct rx_packet *ap, struct rx_call *acall)
{
    int rc = 0;

    MUTEX_ENTER(&rx_quota_mutex);
    if (((ap->header.seq != 1) && (acall->flags & RX_CALL_CLEARED)
         && (acall->state == RX_STATE_PRECALL))
        || ((rx_nFreePackets < rxi_dataQuota + 2)
            && !((ap->header.seq < acall->rnext + rx_initSendWindow)
                 && (acall->flags & RX_CALL_READER_WAIT)))) {
        rc = 1;
    }
    MUTEX_EXIT(&rx_quota_mutex);
    return rc;
}
#endif /* KERNEL */

static void
rxi_CheckReachEvent(struct rxevent *event, void *arg1, void *arg2)
{
    struct rx_connection *conn = arg1;
    struct rx_call *acall = arg2;
    struct rx_call *call = acall;
    struct clock when, now;
    int i, waiting;

    MUTEX_ENTER(&conn->conn_data_lock);
    conn->checkReachEvent = NULL;
    waiting = conn->flags & RX_CONN_ATTACHWAIT;
    if (event)
        conn->refCount--;
    MUTEX_EXIT(&conn->conn_data_lock);

    if (waiting) {
        if (!call) {
            MUTEX_ENTER(&conn->conn_call_lock);
            MUTEX_ENTER(&conn->conn_data_lock);
            for (i = 0; i < RX_MAXCALLS; i++) {
                struct rx_call *tc = conn->call[i];
                if (tc && tc->state == RX_STATE_PRECALL) {
                    call = tc;
                    break;
                }
            }
            if (!call)
                /* Indicate that rxi_CheckReachEvent is no longer running by
                 * clearing the flag.  Must be atomic under conn_data_lock to
                 * avoid a new call slipping by: rxi_CheckConnReach holds
                 * conn_data_lock while checking RX_CONN_ATTACHWAIT.
                 */
                conn->flags &= ~RX_CONN_ATTACHWAIT;
            MUTEX_EXIT(&conn->conn_data_lock);
            MUTEX_EXIT(&conn->conn_call_lock);
        }

        if (call) {
            if (call != acall)
                MUTEX_ENTER(&call->lock);
            rxi_SendAck(call, NULL, 0, RX_ACK_PING, 0);
            if (call != acall)
                MUTEX_EXIT(&call->lock);

            clock_GetTime(&now);
            when = now;
            when.sec += RX_CHECKREACH_TIMEOUT;
            MUTEX_ENTER(&conn->conn_data_lock);
            if (!conn->checkReachEvent) {
                conn->refCount++;
                conn->checkReachEvent =
                    rxevent_PostNow(&when, &now, rxi_CheckReachEvent, conn, 
                                    NULL);
            }
            MUTEX_EXIT(&conn->conn_data_lock);
        }
    }
}

static int
rxi_CheckConnReach(struct rx_connection *conn, struct rx_call *call)
{
    struct rx_service *service = conn->service;
    struct rx_peer *peer = conn->peer;
    afs_uint32 now, lastReach;

    if (service->checkReach == 0)
        return 0;

    now = clock_Sec();
    MUTEX_ENTER(&peer->peer_lock);
    lastReach = peer->lastReachTime;
    MUTEX_EXIT(&peer->peer_lock);
    if (now - lastReach < RX_CHECKREACH_TTL)
        return 0;

    MUTEX_ENTER(&conn->conn_data_lock);
    if (conn->flags & RX_CONN_ATTACHWAIT) {
        MUTEX_EXIT(&conn->conn_data_lock);
        return 1;
    }
    conn->flags |= RX_CONN_ATTACHWAIT;
    MUTEX_EXIT(&conn->conn_data_lock);
    if (!conn->checkReachEvent)
        rxi_CheckReachEvent(NULL, conn, call);

    return 1;
}

/* try to attach call, if authentication is complete */
static void
TryAttach(struct rx_call *acall, osi_socket socket,
          int *tnop, struct rx_call **newcallp,
          int reachOverride)
{
    struct rx_connection *conn = acall->conn;

    if (conn->type == RX_SERVER_CONNECTION
        && acall->state == RX_STATE_PRECALL) {
        /* Don't attach until we have any req'd. authentication. */
        if (RXS_CheckAuthentication(conn->securityObject, conn) == 0) {
            if (reachOverride || rxi_CheckConnReach(conn, acall) == 0)
                rxi_AttachServerProc(acall, socket, tnop, newcallp);
            /* Note:  this does not necessarily succeed; there
             * may not any proc available
             */
        } else {
            rxi_ChallengeOn(acall->conn);
        }
    }
}

/* A data packet has been received off the interface.  This packet is
 * appropriate to the call (the call is in the right state, etc.).  This
 * routine can return a packet to the caller, for re-use */

struct rx_packet *
rxi_ReceiveDataPacket(struct rx_call *call,
                      struct rx_packet *np, int istack,
                      osi_socket socket, afs_uint32 host, u_short port,
                      int *tnop, struct rx_call **newcallp)
{
    int ackNeeded = 0;          /* 0 means no, otherwise ack_reason */
    int newPackets = 0;
    int didHardAck = 0;
    int haveLast = 0;
    afs_uint32 seq; 
    afs_uint32 serial=0, flags=0;
    int isFirst;
    struct rx_packet *tnp;
    struct clock when, now;
    if (rx_stats_active)
        rx_MutexIncrement(rx_stats.dataPacketsRead, rx_stats_mutex);

#ifdef KERNEL
    /* If there are no packet buffers, drop this new packet, unless we can find
     * packet buffers from inactive calls */
    if (!call->error
        && (rxi_OverQuota(RX_PACKET_CLASS_RECEIVE) || TooLow(np, call))) {
        MUTEX_ENTER(&rx_freePktQ_lock);
        rxi_NeedMorePackets = TRUE;
        MUTEX_EXIT(&rx_freePktQ_lock);
        if (rx_stats_active)
            rx_MutexIncrement(rx_stats.noPacketBuffersOnRead, rx_stats_mutex);
        call->rprev = np->header.serial;
        rxi_calltrace(RX_TRACE_DROP, call);
        dpf(("packet %"AFS_PTR_FMT" dropped on receipt - quota problems", np));
        if (rxi_doreclaim)
            rxi_ClearReceiveQueue(call);
        clock_GetTime(&now);
        when = now;
        clock_Add(&when, &rx_softAckDelay);
        if (!call->delayedAckEvent
            || clock_Gt(&call->delayedAckEvent->eventTime, &when)) {
            rxevent_Cancel(call->delayedAckEvent, call,
                           RX_CALL_REFCOUNT_DELAY);
            CALL_HOLD(call, RX_CALL_REFCOUNT_DELAY);
            call->delayedAckEvent =
                rxevent_PostNow(&when, &now, rxi_SendDelayedAck, call, 0);
        }
        /* we've damaged this call already, might as well do it in. */
        return np;
    }
#endif /* KERNEL */

    /*
     * New in AFS 3.5, if the RX_JUMBO_PACKET flag is set then this
     * packet is one of several packets transmitted as a single
     * datagram. Do not send any soft or hard acks until all packets
     * in a jumbogram have been processed. Send negative acks right away.
     */
    for (isFirst = 1, tnp = NULL; isFirst || tnp; isFirst = 0) {
        /* tnp is non-null when there are more packets in the
         * current jumbo gram */
        if (tnp) {
            if (np)
                rxi_FreePacket(np);
            np = tnp;
        }

        seq = np->header.seq;
        serial = np->header.serial;
        flags = np->header.flags;

        /* If the call is in an error state, send an abort message */
        if (call->error)
            return rxi_SendCallAbort(call, np, istack, 0);

        /* The RX_JUMBO_PACKET is set in all but the last packet in each
         * AFS 3.5 jumbogram. */
        if (flags & RX_JUMBO_PACKET) {
            tnp = rxi_SplitJumboPacket(np, host, port, isFirst);
        } else {
            tnp = NULL;
        }

        if (np->header.spare != 0) {
            MUTEX_ENTER(&call->conn->conn_data_lock);
            call->conn->flags |= RX_CONN_USING_PACKET_CKSUM;
            MUTEX_EXIT(&call->conn->conn_data_lock);
        }

        /* The usual case is that this is the expected next packet */
        if (seq == call->rnext) {

            /* Check to make sure it is not a duplicate of one already queued */
            if (queue_IsNotEmpty(&call->rq)
                && queue_First(&call->rq, rx_packet)->header.seq == seq) {
                if (rx_stats_active)
                    rx_MutexIncrement(rx_stats.dupPacketsRead, rx_stats_mutex);
                dpf(("packet %"AFS_PTR_FMT" dropped on receipt - duplicate", np));
                rxevent_Cancel(call->delayedAckEvent, call,
                               RX_CALL_REFCOUNT_DELAY);
                np = rxi_SendAck(call, np, serial, RX_ACK_DUPLICATE, istack);
                ackNeeded = 0;
                call->rprev = seq;
                continue;
            }

            /* It's the next packet. Stick it on the receive queue
             * for this call. Set newPackets to make sure we wake
             * the reader once all packets have been processed */
            np->flags |= RX_PKTFLAG_RQ;
            queue_Prepend(&call->rq, np);
#ifdef RXDEBUG_PACKET
            call->rqc++;
#endif /* RXDEBUG_PACKET */
            call->nSoftAcks++;
            np = NULL;          /* We can't use this anymore */
            newPackets = 1;

            /* If an ack is requested then set a flag to make sure we
             * send an acknowledgement for this packet */
            if (flags & RX_REQUEST_ACK) {
                ackNeeded = RX_ACK_REQUESTED;
            }

            /* Keep track of whether we have received the last packet */
            if (flags & RX_LAST_PACKET) {
                call->flags |= RX_CALL_HAVE_LAST;
                haveLast = 1;
            }

            /* Check whether we have all of the packets for this call */
            if (call->flags & RX_CALL_HAVE_LAST) {
                afs_uint32 tseq;        /* temporary sequence number */
                struct rx_packet *tp;   /* Temporary packet pointer */
                struct rx_packet *nxp;  /* Next pointer, for queue_Scan */

                for (tseq = seq, queue_Scan(&call->rq, tp, nxp, rx_packet)) {
                    if (tseq != tp->header.seq)
                        break;
                    if (tp->header.flags & RX_LAST_PACKET) {
                        call->flags |= RX_CALL_RECEIVE_DONE;
                        break;
                    }
                    tseq++;
                }
            }

            /* Provide asynchronous notification for those who want it
             * (e.g. multi rx) */
            if (call->arrivalProc) {
                (*call->arrivalProc) (call, call->arrivalProcHandle,
                                      call->arrivalProcArg);
                call->arrivalProc = (void (*)())0;
            }

            /* Update last packet received */
            call->rprev = seq;

            /* If there is no server process serving this call, grab
             * one, if available. We only need to do this once. If a
             * server thread is available, this thread becomes a server
             * thread and the server thread becomes a listener thread. */
            if (isFirst) {
                TryAttach(call, socket, tnop, newcallp, 0);
            }
        }
        /* This is not the expected next packet. */
        else {
            /* Determine whether this is a new or old packet, and if it's
             * a new one, whether it fits into the current receive window.
             * Also figure out whether the packet was delivered in sequence.
             * We use the prev variable to determine whether the new packet
             * is the successor of its immediate predecessor in the
             * receive queue, and the missing flag to determine whether
             * any of this packets predecessors are missing.  */

            afs_uint32 prev;    /* "Previous packet" sequence number */
            struct rx_packet *tp;       /* Temporary packet pointer */
            struct rx_packet *nxp;      /* Next pointer, for queue_Scan */
            int missing;        /* Are any predecessors missing? */

            /* If the new packet's sequence number has been sent to the
             * application already, then this is a duplicate */
            if (seq < call->rnext) {
                if (rx_stats_active)
                    rx_MutexIncrement(rx_stats.dupPacketsRead, rx_stats_mutex);
                rxevent_Cancel(call->delayedAckEvent, call,
                               RX_CALL_REFCOUNT_DELAY);
                np = rxi_SendAck(call, np, serial, RX_ACK_DUPLICATE, istack);
                ackNeeded = 0;
                call->rprev = seq;
                continue;
            }

            /* If the sequence number is greater than what can be
             * accomodated by the current window, then send a negative
             * acknowledge and drop the packet */
            if ((call->rnext + call->rwind) <= seq) {
                rxevent_Cancel(call->delayedAckEvent, call,
                               RX_CALL_REFCOUNT_DELAY);
                np = rxi_SendAck(call, np, serial, RX_ACK_EXCEEDS_WINDOW,
                                 istack);
                ackNeeded = 0;
                call->rprev = seq;
                continue;
            }

            /* Look for the packet in the queue of old received packets */
            for (prev = call->rnext - 1, missing =
                 0, queue_Scan(&call->rq, tp, nxp, rx_packet)) {
                /*Check for duplicate packet */
                if (seq == tp->header.seq) {
                    if (rx_stats_active)
                        rx_MutexIncrement(rx_stats.dupPacketsRead, rx_stats_mutex);
                    rxevent_Cancel(call->delayedAckEvent, call,
                                   RX_CALL_REFCOUNT_DELAY);
                    np = rxi_SendAck(call, np, serial, RX_ACK_DUPLICATE,
                                     istack);
                    ackNeeded = 0;
                    call->rprev = seq;
                    goto nextloop;
                }
                /* If we find a higher sequence packet, break out and
                 * insert the new packet here. */
                if (seq < tp->header.seq)
                    break;
                /* Check for missing packet */
                if (tp->header.seq != prev + 1) {
                    missing = 1;
                }

                prev = tp->header.seq;
            }

            /* Keep track of whether we have received the last packet. */
            if (flags & RX_LAST_PACKET) {
                call->flags |= RX_CALL_HAVE_LAST;
            }

            /* It's within the window: add it to the the receive queue.
             * tp is left by the previous loop either pointing at the
             * packet before which to insert the new packet, or at the
             * queue head if the queue is empty or the packet should be
             * appended. */
            np->flags |= RX_PKTFLAG_RQ;
#ifdef RXDEBUG_PACKET
            call->rqc++;
#endif /* RXDEBUG_PACKET */
            queue_InsertBefore(tp, np);
            call->nSoftAcks++;
            np = NULL;

            /* Check whether we have all of the packets for this call */
            if ((call->flags & RX_CALL_HAVE_LAST)
                && !(call->flags & RX_CALL_RECEIVE_DONE)) {
                afs_uint32 tseq;        /* temporary sequence number */

                for (tseq =
                     call->rnext, queue_Scan(&call->rq, tp, nxp, rx_packet)) {
                    if (tseq != tp->header.seq)
                        break;
                    if (tp->header.flags & RX_LAST_PACKET) {
                        call->flags |= RX_CALL_RECEIVE_DONE;
                        break;
                    }
                    tseq++;
                }
            }

            /* We need to send an ack of the packet is out of sequence, 
             * or if an ack was requested by the peer. */
            if (seq != prev + 1 || missing) {
                ackNeeded = RX_ACK_OUT_OF_SEQUENCE;
            } else if (flags & RX_REQUEST_ACK) {
                ackNeeded = RX_ACK_REQUESTED;
            }

            /* Acknowledge the last packet for each call */
            if (flags & RX_LAST_PACKET) {
                haveLast = 1;
            }

            call->rprev = seq;
        }
      nextloop:;
    }

    if (newPackets) {
        /*
         * If the receiver is waiting for an iovec, fill the iovec
         * using the data from the receive queue */
        if (call->flags & RX_CALL_IOVEC_WAIT) {
            didHardAck = rxi_FillReadVec(call, serial);
            /* the call may have been aborted */
            if (call->error) {
                return NULL;
            }
            if (didHardAck) {
                ackNeeded = 0;
            }
        }

        /* Wakeup the reader if any */
        if ((call->flags & RX_CALL_READER_WAIT)
            && (!(call->flags & RX_CALL_IOVEC_WAIT) || !(call->iovNBytes)
                || (call->iovNext >= call->iovMax)
                || (call->flags & RX_CALL_RECEIVE_DONE))) {
            call->flags &= ~RX_CALL_READER_WAIT;
#ifdef  RX_ENABLE_LOCKS
            CV_BROADCAST(&call->cv_rq);
#else
            osi_rxWakeup(&call->rq);
#endif
        }
    }

    /*
     * Send an ack when requested by the peer, or once every
     * rxi_SoftAckRate packets until the last packet has been
     * received. Always send a soft ack for the last packet in
     * the server's reply. */
    if (ackNeeded) {
        rxevent_Cancel(call->delayedAckEvent, call, RX_CALL_REFCOUNT_DELAY);
        np = rxi_SendAck(call, np, serial, ackNeeded, istack);
    } else if (call->nSoftAcks > (u_short) rxi_SoftAckRate) {
        rxevent_Cancel(call->delayedAckEvent, call, RX_CALL_REFCOUNT_DELAY);
        np = rxi_SendAck(call, np, serial, RX_ACK_IDLE, istack);
    } else if (call->nSoftAcks) {
        clock_GetTime(&now);
        when = now;
        if (haveLast && !(flags & RX_CLIENT_INITIATED)) {
            clock_Add(&when, &rx_lastAckDelay);
        } else {
            clock_Add(&when, &rx_softAckDelay);
        }
        if (!call->delayedAckEvent
            || clock_Gt(&call->delayedAckEvent->eventTime, &when)) {
            rxevent_Cancel(call->delayedAckEvent, call,
                           RX_CALL_REFCOUNT_DELAY);
            CALL_HOLD(call, RX_CALL_REFCOUNT_DELAY);
            call->delayedAckEvent =
                rxevent_PostNow(&when, &now, rxi_SendDelayedAck, call, 0);
        }
    } else if (call->flags & RX_CALL_RECEIVE_DONE) {
        rxevent_Cancel(call->delayedAckEvent, call, RX_CALL_REFCOUNT_DELAY);
    }

    return np;
}

#ifdef  ADAPT_WINDOW
static void rxi_ComputeRate();
#endif

static void
rxi_UpdatePeerReach(struct rx_connection *conn, struct rx_call *acall)
{
    struct rx_peer *peer = conn->peer;

    MUTEX_ENTER(&peer->peer_lock);
    peer->lastReachTime = clock_Sec();
    MUTEX_EXIT(&peer->peer_lock);

    MUTEX_ENTER(&conn->conn_data_lock);
    if (conn->flags & RX_CONN_ATTACHWAIT) {
        int i;

        conn->flags &= ~RX_CONN_ATTACHWAIT;
        MUTEX_EXIT(&conn->conn_data_lock);

        for (i = 0; i < RX_MAXCALLS; i++) {
            struct rx_call *call = conn->call[i];
            if (call) {
                if (call != acall)
                    MUTEX_ENTER(&call->lock);
                /* tnop can be null if newcallp is null */
                TryAttach(call, (osi_socket) - 1, NULL, NULL, 1);
                if (call != acall)
                    MUTEX_EXIT(&call->lock);
            }
        }
    } else
        MUTEX_EXIT(&conn->conn_data_lock);
}

#if defined(RXDEBUG) && defined(AFS_NT40_ENV)
static const char *
rx_ack_reason(int reason)
{
    switch (reason) {
    case RX_ACK_REQUESTED:
        return "requested";
    case RX_ACK_DUPLICATE:
        return "duplicate";
    case RX_ACK_OUT_OF_SEQUENCE:
        return "sequence";
    case RX_ACK_EXCEEDS_WINDOW:
        return "window";
    case RX_ACK_NOSPACE:
        return "nospace";
    case RX_ACK_PING:
        return "ping";
    case RX_ACK_PING_RESPONSE:
        return "response";
    case RX_ACK_DELAY:
        return "delay";
    case RX_ACK_IDLE:
        return "idle";
    default:
        return "unknown!!";
    }
}
#endif


/* rxi_ComputePeerNetStats
 *
 * Called exclusively by rxi_ReceiveAckPacket to compute network link
 * estimates (like RTT and throughput) based on ack packets.  Caller
 * must ensure that the packet in question is the right one (i.e.
 * serial number matches).
 */
static void
rxi_ComputePeerNetStats(struct rx_call *call, struct rx_packet *p,
                        struct rx_ackPacket *ap, struct rx_packet *np)
{
    struct rx_peer *peer = call->conn->peer;

    /* Use RTT if not delayed by client and
     * ignore packets that were retransmitted. */
    if (!(p->flags & RX_PKTFLAG_ACKED) &&
        ap->reason != RX_ACK_DELAY &&
        clock_Eq(&p->timeSent, &p->firstSent))
        rxi_ComputeRoundTripTime(p, &p->timeSent, peer);
#ifdef ADAPT_WINDOW
    rxi_ComputeRate(peer, call, p, np, ap->reason);
#endif
}

/* The real smarts of the whole thing.  */
struct rx_packet *
rxi_ReceiveAckPacket(struct rx_call *call, struct rx_packet *np,
                     int istack)
{
    struct rx_ackPacket *ap;
    int nAcks;
    struct rx_packet *tp;
    struct rx_packet *nxp;      /* Next packet pointer for queue_Scan */
    struct rx_connection *conn = call->conn;
    struct rx_peer *peer = conn->peer;
    afs_uint32 first;
    afs_uint32 serial;
    /* because there are CM's that are bogus, sending weird values for this. */
    afs_uint32 skew = 0;
    int nbytes;
    int missing;
    int backedOff = 0;
    int acked;
    int nNacked = 0;
    int newAckCount = 0;
    u_short maxMTU = 0;         /* Set if peer supports AFS 3.4a jumbo datagrams */
    int maxDgramPackets = 0;    /* Set if peer supports AFS 3.5 jumbo datagrams */

    if (rx_stats_active)
        rx_MutexIncrement(rx_stats.ackPacketsRead, rx_stats_mutex);
    ap = (struct rx_ackPacket *)rx_DataOf(np);
    nbytes = rx_Contiguous(np) - (int)((ap->acks) - (u_char *) ap);
    if (nbytes < 0)
        return np;              /* truncated ack packet */

    /* depends on ack packet struct */
    nAcks = MIN((unsigned)nbytes, (unsigned)ap->nAcks);
    first = ntohl(ap->firstPacket);
    serial = ntohl(ap->serial);
    /* temporarily disabled -- needs to degrade over time 
     * skew = ntohs(ap->maxSkew); */

    /* Ignore ack packets received out of order */
    if (first < call->tfirst) {
        return np;
    }

    if (np->header.flags & RX_SLOW_START_OK) {
        call->flags |= RX_CALL_SLOW_START_OK;
    }

    if (ap->reason == RX_ACK_PING_RESPONSE)
        rxi_UpdatePeerReach(conn, call);

#ifdef RXDEBUG
#ifdef AFS_NT40_ENV
    if (rxdebug_active) {
        char msg[512];
        size_t len;

        len = _snprintf(msg, sizeof(msg),
                        "tid[%d] RACK: reason %s serial %u previous %u seq %u skew %d first %u acks %u space %u ",
                         GetCurrentThreadId(), rx_ack_reason(ap->reason), 
                         ntohl(ap->serial), ntohl(ap->previousPacket),
                         (unsigned int)np->header.seq, (unsigned int)skew, 
                         ntohl(ap->firstPacket), ap->nAcks, ntohs(ap->bufferSpace) );
        if (nAcks) {
            int offset;

            for (offset = 0; offset < nAcks && len < sizeof(msg); offset++) 
                msg[len++] = (ap->acks[offset] == RX_ACK_TYPE_NACK ? '-' : '*');
        }
        msg[len++]='\n';
        msg[len] = '\0';
        OutputDebugString(msg);
    }
#else /* AFS_NT40_ENV */
    if (rx_Log) {
        fprintf(rx_Log,
                "RACK: reason %x previous %u seq %u serial %u skew %d first %u",
                ap->reason, ntohl(ap->previousPacket),
                (unsigned int)np->header.seq, (unsigned int)serial,
                (unsigned int)skew, ntohl(ap->firstPacket));
        if (nAcks) {
            int offset;
            for (offset = 0; offset < nAcks; offset++)
                putc(ap->acks[offset] == RX_ACK_TYPE_NACK ? '-' : '*',
                     rx_Log);
        }
        putc('\n', rx_Log);
    }
#endif /* AFS_NT40_ENV */
#endif

    /* Update the outgoing packet skew value to the latest value of
     * the peer's incoming packet skew value.  The ack packet, of
     * course, could arrive out of order, but that won't affect things
     * much */
    MUTEX_ENTER(&peer->peer_lock);
    peer->outPacketSkew = skew;

    /* Check for packets that no longer need to be transmitted, and
     * discard them.  This only applies to packets positively
     * acknowledged as having been sent to the peer's upper level.
     * All other packets must be retained.  So only packets with
     * sequence numbers < ap->firstPacket are candidates. */
    for (queue_Scan(&call->tq, tp, nxp, rx_packet)) {
        if (tp->header.seq >= first)
            break;
        call->tfirst = tp->header.seq + 1;
        rxi_ComputePeerNetStats(call, tp, ap, np);
        if (!(tp->flags & RX_PKTFLAG_ACKED)) {
            newAckCount++;
        }
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
        /* XXX Hack. Because we have to release the global rx lock when sending
         * packets (osi_NetSend) we drop all acks while we're traversing the tq
         * in rxi_Start sending packets out because packets may move to the
         * freePacketQueue as result of being here! So we drop these packets until
         * we're safely out of the traversing. Really ugly! 
         * To make it even uglier, if we're using fine grain locking, we can
         * set the ack bits in the packets and have rxi_Start remove the packets
         * when it's done transmitting.
         */
        if (call->flags & RX_CALL_TQ_BUSY) {
#ifdef RX_ENABLE_LOCKS
            tp->flags |= RX_PKTFLAG_ACKED;
            call->flags |= RX_CALL_TQ_SOME_ACKED;
#else /* RX_ENABLE_LOCKS */
            break;
#endif /* RX_ENABLE_LOCKS */
        } else
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
        {
            queue_Remove(tp);
            tp->flags &= ~RX_PKTFLAG_TQ;
#ifdef RXDEBUG_PACKET
            call->tqc--;
#endif /* RXDEBUG_PACKET */
            rxi_FreePacket(tp); /* rxi_FreePacket mustn't wake up anyone, preemptively. */
        }
    }

#ifdef ADAPT_WINDOW
    /* Give rate detector a chance to respond to ping requests */
    if (ap->reason == RX_ACK_PING_RESPONSE) {
        rxi_ComputeRate(peer, call, 0, np, ap->reason);
    }
#endif

    /* N.B. we don't turn off any timers here.  They'll go away by themselves, anyway */

    /* Now go through explicit acks/nacks and record the results in
     * the waiting packets.  These are packets that can't be released
     * yet, even with a positive acknowledge.  This positive
     * acknowledge only means the packet has been received by the
     * peer, not that it will be retained long enough to be sent to
     * the peer's upper level.  In addition, reset the transmit timers
     * of any missing packets (those packets that must be missing
     * because this packet was out of sequence) */

    call->nSoftAcked = 0;
    for (missing = 0, queue_Scan(&call->tq, tp, nxp, rx_packet)) {
        /* Update round trip time if the ack was stimulated on receipt
         * of this packet */
#ifdef AFS_GLOBAL_RXLOCK_KERNEL
#ifdef RX_ENABLE_LOCKS
        if (tp->header.seq >= first)
#endif /* RX_ENABLE_LOCKS */
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
            rxi_ComputePeerNetStats(call, tp, ap, np);

        /* Set the acknowledge flag per packet based on the
         * information in the ack packet. An acknowlegded packet can
         * be downgraded when the server has discarded a packet it
         * soacked previously, or when an ack packet is received
         * out of sequence. */
        if (tp->header.seq < first) {
            /* Implicit ack information */
            if (!(tp->flags & RX_PKTFLAG_ACKED)) {
                newAckCount++;
            }
            tp->flags |= RX_PKTFLAG_ACKED;
        } else if (tp->header.seq < first + nAcks) {
            /* Explicit ack information:  set it in the packet appropriately */
            if (ap->acks[tp->header.seq - first] == RX_ACK_TYPE_ACK) {
                if (!(tp->flags & RX_PKTFLAG_ACKED)) {
                    newAckCount++;
                    tp->flags |= RX_PKTFLAG_ACKED;
                }
                if (missing) {
                    nNacked++;
                } else {
                    call->nSoftAcked++;
                }
            } else /* RX_ACK_TYPE_NACK */ {
                tp->flags &= ~RX_PKTFLAG_ACKED;
                missing = 1;
            }
        } else {
            tp->flags &= ~RX_PKTFLAG_ACKED;
            missing = 1;
        }

        /*
         * Following the suggestion of Phil Kern, we back off the peer's
         * timeout value for future packets until a successful response
         * is received for an initial transmission.
         */
        if (missing && !backedOff) {
            struct clock c = peer->timeout;
            struct clock max_to = {3, 0};

            clock_Add(&peer->timeout, &c);
            if (clock_Gt(&peer->timeout, &max_to))
                peer->timeout = max_to;
            backedOff = 1;
        }

        /* If packet isn't yet acked, and it has been transmitted at least 
         * once, reset retransmit time using latest timeout 
         * ie, this should readjust the retransmit timer for all outstanding 
         * packets...  So we don't just retransmit when we should know better*/

        if (!(tp->flags & RX_PKTFLAG_ACKED) && !clock_IsZero(&tp->retryTime)) {
            tp->retryTime = tp->timeSent;
            clock_Add(&tp->retryTime, &peer->timeout);
            /* shift by eight because one quarter-sec ~ 256 milliseconds */
            clock_Addmsec(&(tp->retryTime), ((afs_uint32) tp->backoff) << 8);
        }
    }

    /* If the window has been extended by this acknowledge packet,
     * then wakeup a sender waiting in alloc for window space, or try
     * sending packets now, if he's been sitting on packets due to
     * lack of window space */
    if (call->tnext < (call->tfirst + call->twind)) {
#ifdef  RX_ENABLE_LOCKS
        CV_SIGNAL(&call->cv_twind);
#else
        if (call->flags & RX_CALL_WAIT_WINDOW_ALLOC) {
            call->flags &= ~RX_CALL_WAIT_WINDOW_ALLOC;
            osi_rxWakeup(&call->twind);
        }
#endif
        if (call->flags & RX_CALL_WAIT_WINDOW_SEND) {
            call->flags &= ~RX_CALL_WAIT_WINDOW_SEND;
        }
    }

    /* if the ack packet has a receivelen field hanging off it,
     * update our state */
    if (np->length >= rx_AckDataSize(ap->nAcks) + 2 * sizeof(afs_int32)) {
        afs_uint32 tSize;

        /* If the ack packet has a "recommended" size that is less than 
         * what I am using now, reduce my size to match */
        rx_packetread(np, rx_AckDataSize(ap->nAcks) + (int)sizeof(afs_int32),
                      (int)sizeof(afs_int32), &tSize);
        tSize = (afs_uint32) ntohl(tSize);
        peer->natMTU = rxi_AdjustIfMTU(MIN(tSize, peer->ifMTU));

        /* Get the maximum packet size to send to this peer */
        rx_packetread(np, rx_AckDataSize(ap->nAcks), (int)sizeof(afs_int32),
                      &tSize);
        tSize = (afs_uint32) ntohl(tSize);
        tSize = (afs_uint32) MIN(tSize, rx_MyMaxSendSize);
        tSize = rxi_AdjustMaxMTU(peer->natMTU, tSize);

        /* sanity check - peer might have restarted with different params.
         * If peer says "send less", dammit, send less...  Peer should never 
         * be unable to accept packets of the size that prior AFS versions would
         * send without asking.  */
        if (peer->maxMTU != tSize) {
            if (peer->maxMTU > tSize) /* possible cong., maxMTU decreased */
                peer->congestSeq++;
            peer->maxMTU = tSize;
            peer->MTU = MIN(tSize, peer->MTU);
            call->MTU = MIN(call->MTU, tSize);
        }

        if (np->length == rx_AckDataSize(ap->nAcks) + 3 * sizeof(afs_int32)) {
            /* AFS 3.4a */
            rx_packetread(np,
                          rx_AckDataSize(ap->nAcks) + 2 * (int)sizeof(afs_int32),
                          (int)sizeof(afs_int32), &tSize);
            tSize = (afs_uint32) ntohl(tSize);  /* peer's receive window, if it's */
            if (tSize < call->twind) {  /* smaller than our send */
                call->twind = tSize;    /* window, we must send less... */
                call->ssthresh = MIN(call->twind, call->ssthresh);
                call->conn->twind[call->channel] = call->twind;
            }

            /* Only send jumbograms to 3.4a fileservers. 3.3a RX gets the
             * network MTU confused with the loopback MTU. Calculate the
             * maximum MTU here for use in the slow start code below.
             */
            maxMTU = peer->maxMTU;
            /* Did peer restart with older RX version? */
            if (peer->maxDgramPackets > 1) {
                peer->maxDgramPackets = 1;
            }
        } else if (np->length >=
                   rx_AckDataSize(ap->nAcks) + 4 * sizeof(afs_int32)) {
            /* AFS 3.5 */
            rx_packetread(np,
                          rx_AckDataSize(ap->nAcks) + 2 * (int)sizeof(afs_int32),
                          sizeof(afs_int32), &tSize);
            tSize = (afs_uint32) ntohl(tSize);
            /*
             * As of AFS 3.5 we set the send window to match the receive window. 
             */
            if (tSize < call->twind) {
                call->twind = tSize;
                call->conn->twind[call->channel] = call->twind;
                call->ssthresh = MIN(call->twind, call->ssthresh);
            } else if (tSize > call->twind) {
                call->twind = tSize;
                call->conn->twind[call->channel] = call->twind;
            }

            /*
             * As of AFS 3.5, a jumbogram is more than one fixed size
             * packet transmitted in a single UDP datagram. If the remote
             * MTU is smaller than our local MTU then never send a datagram
             * larger than the natural MTU.
             */
            rx_packetread(np,
                          rx_AckDataSize(ap->nAcks) + 3 * (int)sizeof(afs_int32),
                          (int)sizeof(afs_int32), &tSize);
            maxDgramPackets = (afs_uint32) ntohl(tSize);
            maxDgramPackets = MIN(maxDgramPackets, rxi_nDgramPackets);
            maxDgramPackets =
                MIN(maxDgramPackets, (int)(peer->ifDgramPackets));
            maxDgramPackets = MIN(maxDgramPackets, tSize);
            if (maxDgramPackets > 1) {
                peer->maxDgramPackets = maxDgramPackets;
                call->MTU = RX_JUMBOBUFFERSIZE + RX_HEADER_SIZE;
            } else {
                peer->maxDgramPackets = 1;
                call->MTU = peer->natMTU;
            }
        } else if (peer->maxDgramPackets > 1) {
            /* Restarted with lower version of RX */
            peer->maxDgramPackets = 1;
        }
    } else if (peer->maxDgramPackets > 1
               || peer->maxMTU != OLD_MAX_PACKET_SIZE) {
        /* Restarted with lower version of RX */
        peer->maxMTU = OLD_MAX_PACKET_SIZE;
        peer->natMTU = OLD_MAX_PACKET_SIZE;
        peer->MTU = OLD_MAX_PACKET_SIZE;
        peer->maxDgramPackets = 1;
        peer->nDgramPackets = 1;
        peer->congestSeq++;
        call->MTU = OLD_MAX_PACKET_SIZE;
    }

    if (nNacked) {
        /*
         * Calculate how many datagrams were successfully received after
         * the first missing packet and adjust the negative ack counter
         * accordingly.
         */
        call->nAcks = 0;
        call->nNacks++;
        nNacked = (nNacked + call->nDgramPackets - 1) / call->nDgramPackets;
        if (call->nNacks < nNacked) {
            call->nNacks = nNacked;
        }
    } else {
        call->nAcks += newAckCount;
        call->nNacks = 0;
    }

    if (call->flags & RX_CALL_FAST_RECOVER) {
        if (nNacked) {
            call->cwind = MIN((int)(call->cwind + 1), rx_maxSendWindow);
        } else {
            call->flags &= ~RX_CALL_FAST_RECOVER;
            call->cwind = call->nextCwind;
            call->nextCwind = 0;
            call->nAcks = 0;
        }
        call->nCwindAcks = 0;
    } else if (nNacked && call->nNacks >= (u_short) rx_nackThreshold) {
        /* Three negative acks in a row trigger congestion recovery */
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
        MUTEX_EXIT(&peer->peer_lock);
        if (call->flags & RX_CALL_FAST_RECOVER_WAIT) {
            /* someone else is waiting to start recovery */
            return np;
        }
        call->flags |= RX_CALL_FAST_RECOVER_WAIT;
        rxi_WaitforTQBusy(call);
        MUTEX_ENTER(&peer->peer_lock);
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
        call->flags &= ~RX_CALL_FAST_RECOVER_WAIT;
        call->flags |= RX_CALL_FAST_RECOVER;
        call->ssthresh = MAX(4, MIN((int)call->cwind, (int)call->twind)) >> 1;
        call->cwind =
            MIN((int)(call->ssthresh + rx_nackThreshold), rx_maxSendWindow);
        call->nDgramPackets = MAX(2, (int)call->nDgramPackets) >> 1;
        call->nextCwind = call->ssthresh;
        call->nAcks = 0;
        call->nNacks = 0;
        peer->MTU = call->MTU;
        peer->cwind = call->nextCwind;
        peer->nDgramPackets = call->nDgramPackets;
        peer->congestSeq++;
        call->congestSeq = peer->congestSeq;
        /* Reset the resend times on the packets that were nacked
         * so we will retransmit as soon as the window permits*/
        for (acked = 0, queue_ScanBackwards(&call->tq, tp, nxp, rx_packet)) {
            if (acked) {
                if (!(tp->flags & RX_PKTFLAG_ACKED)) {
                    clock_Zero(&tp->retryTime);
                }
            } else if (tp->flags & RX_PKTFLAG_ACKED) {
                acked = 1;
            }
        }
    } else {
        /* If cwind is smaller than ssthresh, then increase
         * the window one packet for each ack we receive (exponential
         * growth).
         * If cwind is greater than or equal to ssthresh then increase
         * the congestion window by one packet for each cwind acks we
         * receive (linear growth).  */
        if (call->cwind < call->ssthresh) {
            call->cwind =
                MIN((int)call->ssthresh, (int)(call->cwind + newAckCount));
            call->nCwindAcks = 0;
        } else {
            call->nCwindAcks += newAckCount;
            if (call->nCwindAcks >= call->cwind) {
                call->nCwindAcks = 0;
                call->cwind = MIN((int)(call->cwind + 1), rx_maxSendWindow);
            }
        }
        /*
         * If we have received several acknowledgements in a row then
         * it is time to increase the size of our datagrams
         */
        if ((int)call->nAcks > rx_nDgramThreshold) {
            if (peer->maxDgramPackets > 1) {
                if (call->nDgramPackets < peer->maxDgramPackets) {
                    call->nDgramPackets++;
                }
                call->MTU = RX_HEADER_SIZE + RX_JUMBOBUFFERSIZE;
            } else if (call->MTU < peer->maxMTU) {
                call->MTU += peer->natMTU;
                call->MTU = MIN(call->MTU, peer->maxMTU);
            }
            call->nAcks = 0;
        }
    }

    MUTEX_EXIT(&peer->peer_lock);       /* rxi_Start will lock peer. */

    /* Servers need to hold the call until all response packets have
     * been acknowledged. Soft acks are good enough since clients
     * are not allowed to clear their receive queues. */
    if (call->state == RX_STATE_HOLD
        && call->tfirst + call->nSoftAcked >= call->tnext) {
        call->state = RX_STATE_DALLY;
        rxi_ClearTransmitQueue(call, 0);
        rxevent_Cancel(call->keepAliveEvent, call, RX_CALL_REFCOUNT_ALIVE);
    } else if (!queue_IsEmpty(&call->tq)) {
        rxi_Start(0, call, 0, istack);
    }
    return np;
}

/* Received a response to a challenge packet */
struct rx_packet *
rxi_ReceiveResponsePacket(struct rx_connection *conn,
                          struct rx_packet *np, int istack)
{
    int error;

    /* Ignore the packet if we're the client */
    if (conn->type == RX_CLIENT_CONNECTION)
        return np;

    /* If already authenticated, ignore the packet (it's probably a retry) */
    if (RXS_CheckAuthentication(conn->securityObject, conn) == 0)
        return np;

    /* Otherwise, have the security object evaluate the response packet */
    error = RXS_CheckResponse(conn->securityObject, conn, np);
    if (error) {
        /* If the response is invalid, reset the connection, sending
         * an abort to the peer */
#ifndef KERNEL
        rxi_Delay(1);
#endif
        rxi_ConnectionError(conn, error);
        MUTEX_ENTER(&conn->conn_data_lock);
        np = rxi_SendConnectionAbort(conn, np, istack, 0);
        MUTEX_EXIT(&conn->conn_data_lock);
        return np;
    } else {
        /* If the response is valid, any calls waiting to attach
         * servers can now do so */
        int i;

        for (i = 0; i < RX_MAXCALLS; i++) {
            struct rx_call *call = conn->call[i];
            if (call) {
                MUTEX_ENTER(&call->lock);
                if (call->state == RX_STATE_PRECALL)
                    rxi_AttachServerProc(call, (osi_socket) - 1, NULL, NULL);
                /* tnop can be null if newcallp is null */
                MUTEX_EXIT(&call->lock);
            }
        }

        /* Update the peer reachability information, just in case
         * some calls went into attach-wait while we were waiting
         * for authentication..
         */
        rxi_UpdatePeerReach(conn, NULL);
    }
    return np;
}

/* A client has received an authentication challenge: the security
 * object is asked to cough up a respectable response packet to send
 * back to the server.  The server is responsible for retrying the
 * challenge if it fails to get a response. */

struct rx_packet *
rxi_ReceiveChallengePacket(struct rx_connection *conn,
                           struct rx_packet *np, int istack)
{
    int error;

    /* Ignore the challenge if we're the server */
    if (conn->type == RX_SERVER_CONNECTION)
        return np;

    /* Ignore the challenge if the connection is otherwise idle; someone's
     * trying to use us as an oracle. */
    if (!rxi_HasActiveCalls(conn))
        return np;

    /* Send the security object the challenge packet.  It is expected to fill
     * in the response. */
    error = RXS_GetResponse(conn->securityObject, conn, np);

    /* If the security object is unable to return a valid response, reset the
     * connection and send an abort to the peer.  Otherwise send the response
     * packet to the peer connection. */
    if (error) {
        rxi_ConnectionError(conn, error);
        MUTEX_ENTER(&conn->conn_data_lock);
        np = rxi_SendConnectionAbort(conn, np, istack, 0);
        MUTEX_EXIT(&conn->conn_data_lock);
    } else {
        np = rxi_SendSpecial((struct rx_call *)0, conn, np,
                             RX_PACKET_TYPE_RESPONSE, NULL, -1, istack);
    }
    return np;
}


/* Find an available server process to service the current request in
 * the given call structure.  If one isn't available, queue up this
 * call so it eventually gets one */
void
rxi_AttachServerProc(struct rx_call *call,
                     osi_socket socket, int *tnop,
                     struct rx_call **newcallp)
{
    struct rx_serverQueueEntry *sq;
    struct rx_service *service = call->conn->service;
    int haveQuota = 0;

    /* May already be attached */
    if (call->state == RX_STATE_ACTIVE)
        return;

    MUTEX_ENTER(&rx_serverPool_lock);

    haveQuota = QuotaOK(service);
    if ((!haveQuota) || queue_IsEmpty(&rx_idleServerQueue)) {
        /* If there are no processes available to service this call,
         * put the call on the incoming call queue (unless it's
         * already on the queue).
         */
#ifdef RX_ENABLE_LOCKS
        if (haveQuota)
            ReturnToServerPool(service);
#endif /* RX_ENABLE_LOCKS */

        if (!(call->flags & RX_CALL_WAIT_PROC)) {
            call->flags |= RX_CALL_WAIT_PROC;
            MUTEX_ENTER(&rx_waiting_mutex);
            rx_nWaiting++;
            rx_nWaited++;
            MUTEX_EXIT(&rx_waiting_mutex);
            rxi_calltrace(RX_CALL_ARRIVAL, call);
            SET_CALL_QUEUE_LOCK(call, &rx_serverPool_lock);
            queue_Append(&rx_incomingCallQueue, call);
        }
    } else {
        sq = queue_First(&rx_idleServerQueue, rx_serverQueueEntry);

        /* If hot threads are enabled, and both newcallp and sq->socketp
         * are non-null, then this thread will process the call, and the
         * idle server thread will start listening on this threads socket.
         */
        queue_Remove(sq);
        if (rx_enable_hot_thread && newcallp && sq->socketp) {
            *newcallp = call;
            *tnop = sq->tno;
            *sq->socketp = socket;
            clock_GetTime(&call->startTime);
            CALL_HOLD(call, RX_CALL_REFCOUNT_BEGIN);
        } else {
            sq->newcall = call;
        }
        if (call->flags & RX_CALL_WAIT_PROC) {
            /* Conservative:  I don't think this should happen */
            call->flags &= ~RX_CALL_WAIT_PROC;
            if (queue_IsOnQueue(call)) {
                queue_Remove(call);
                
                MUTEX_ENTER(&rx_waiting_mutex);
                rx_nWaiting--;
                MUTEX_EXIT(&rx_waiting_mutex);
            }
        }
        call->state = RX_STATE_ACTIVE;
        call->mode = RX_MODE_RECEIVING;
#ifdef RX_KERNEL_TRACE
        {
            int glockOwner = ISAFS_GLOCK();
            if (!glockOwner)
                AFS_GLOCK();
            afs_Trace3(afs_iclSetp, CM_TRACE_WASHERE, ICL_TYPE_STRING,
                       __FILE__, ICL_TYPE_INT32, __LINE__, ICL_TYPE_POINTER,
                       call);
            if (!glockOwner)
                AFS_GUNLOCK();
        }
#endif
        if (call->flags & RX_CALL_CLEARED) {
            /* send an ack now to start the packet flow up again */
            call->flags &= ~RX_CALL_CLEARED;
            rxi_SendAck(call, 0, 0, RX_ACK_DELAY, 0);
        }
#ifdef  RX_ENABLE_LOCKS
        CV_SIGNAL(&sq->cv);
#else
        service->nRequestsRunning++;
        if (service->nRequestsRunning <= service->minProcs)
            rxi_minDeficit--;
        rxi_availProcs--;
        osi_rxWakeup(sq);
#endif
    }
    MUTEX_EXIT(&rx_serverPool_lock);
}

/* Delay the sending of an acknowledge event for a short while, while
 * a new call is being prepared (in the case of a client) or a reply
 * is being prepared (in the case of a server).  Rather than sending
 * an ack packet, an ACKALL packet is sent. */
void
rxi_AckAll(struct rxevent *event, struct rx_call *call, char *dummy)
{
#ifdef RX_ENABLE_LOCKS
    if (event) {
        MUTEX_ENTER(&call->lock);
        call->delayedAckEvent = NULL;
        CALL_RELE(call, RX_CALL_REFCOUNT_ACKALL);
    }
    rxi_SendSpecial(call, call->conn, (struct rx_packet *)0,
                    RX_PACKET_TYPE_ACKALL, NULL, 0, 0);
    if (event)
        MUTEX_EXIT(&call->lock);
#else /* RX_ENABLE_LOCKS */
    if (event)
        call->delayedAckEvent = NULL;
    rxi_SendSpecial(call, call->conn, (struct rx_packet *)0,
                    RX_PACKET_TYPE_ACKALL, NULL, 0, 0);
#endif /* RX_ENABLE_LOCKS */
}

void
rxi_SendDelayedAck(struct rxevent *event, void *arg1, void *unused)
{
    struct rx_call *call = arg1;
#ifdef RX_ENABLE_LOCKS
    if (event) {
        MUTEX_ENTER(&call->lock);
        if (event == call->delayedAckEvent)
            call->delayedAckEvent = NULL;
        CALL_RELE(call, RX_CALL_REFCOUNT_DELAY);
    }
    (void)rxi_SendAck(call, 0, 0, RX_ACK_DELAY, 0);
    if (event)
        MUTEX_EXIT(&call->lock);
#else /* RX_ENABLE_LOCKS */
    if (event)
        call->delayedAckEvent = NULL;
    (void)rxi_SendAck(call, 0, 0, RX_ACK_DELAY, 0);
#endif /* RX_ENABLE_LOCKS */
}


#ifdef RX_ENABLE_LOCKS
/* Set ack in all packets in transmit queue. rxi_Start will deal with
 * clearing them out.
 */
static void
rxi_SetAcksInTransmitQueue(struct rx_call *call)
{
    struct rx_packet *p, *tp;
    int someAcked = 0;

    for (queue_Scan(&call->tq, p, tp, rx_packet)) {
        p->flags |= RX_PKTFLAG_ACKED;
        someAcked = 1;
    }
    if (someAcked) {
        call->flags |= RX_CALL_TQ_CLEARME;
        call->flags |= RX_CALL_TQ_SOME_ACKED;
    }

    rxevent_Cancel(call->resendEvent, call, RX_CALL_REFCOUNT_RESEND);
    call->tfirst = call->tnext;
    call->nSoftAcked = 0;

    if (call->flags & RX_CALL_FAST_RECOVER) {
        call->flags &= ~RX_CALL_FAST_RECOVER;
        call->cwind = call->nextCwind;
        call->nextCwind = 0;
    }

    CV_SIGNAL(&call->cv_twind);
}
#endif /* RX_ENABLE_LOCKS */

/* Clear out the transmit queue for the current call (all packets have
 * been received by peer) */
void
rxi_ClearTransmitQueue(struct rx_call *call, int force)
{
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
    struct rx_packet *p, *tp;

    if (!force && (call->flags & RX_CALL_TQ_BUSY)) {
        int someAcked = 0;
        for (queue_Scan(&call->tq, p, tp, rx_packet)) {
            p->flags |= RX_PKTFLAG_ACKED;
            someAcked = 1;
        }
        if (someAcked) {
            call->flags |= RX_CALL_TQ_CLEARME;
            call->flags |= RX_CALL_TQ_SOME_ACKED;
        }
    } else {
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
#ifdef RXDEBUG_PACKET
        call->tqc -=
#endif /* RXDEBUG_PACKET */
            rxi_FreePackets(0, &call->tq);
        if (call->tqWaiters || (call->flags & RX_CALL_TQ_WAIT)) {
#ifdef RX_ENABLE_LOCKS
            CV_BROADCAST(&call->cv_tq);
#else /* RX_ENABLE_LOCKS */
            osi_rxWakeup(&call->tq);
#endif /* RX_ENABLE_LOCKS */
        }
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
        call->flags &= ~RX_CALL_TQ_CLEARME;
    }
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */

    rxevent_Cancel(call->resendEvent, call, RX_CALL_REFCOUNT_RESEND);
    call->tfirst = call->tnext; /* implicitly acknowledge all data already sent */
    call->nSoftAcked = 0;

    if (call->flags & RX_CALL_FAST_RECOVER) {
        call->flags &= ~RX_CALL_FAST_RECOVER;
        call->cwind = call->nextCwind;
    }
#ifdef  RX_ENABLE_LOCKS
    CV_SIGNAL(&call->cv_twind);
#else
    osi_rxWakeup(&call->twind);
#endif
}

void
rxi_ClearReceiveQueue(struct rx_call *call)
{
    if (queue_IsNotEmpty(&call->rq)) {
        u_short count;
        
        count = rxi_FreePackets(0, &call->rq);
        rx_packetReclaims += count;
#ifdef RXDEBUG_PACKET
        call->rqc -= count;
        if ( call->rqc != 0 ) 
            dpf(("rxi_ClearReceiveQueue call %"AFS_PTR_FMT" rqc %u != 0", call, call->rqc));
#endif
        call->flags &= ~(RX_CALL_RECEIVE_DONE | RX_CALL_HAVE_LAST);
    }
    if (call->state == RX_STATE_PRECALL) {
        call->flags |= RX_CALL_CLEARED;
    }
}

/* Send an abort packet for the specified call */
struct rx_packet *
rxi_SendCallAbort(struct rx_call *call, struct rx_packet *packet,
                  int istack, int force)
{
    afs_int32 error;
    struct clock when, now;

    if (!call->error)
        return packet;

    /* Clients should never delay abort messages */
    if (rx_IsClientConn(call->conn))
        force = 1;

    if (call->abortCode != call->error) {
        call->abortCode = call->error;
        call->abortCount = 0;
    }

    if (force || rxi_callAbortThreshhold == 0
        || call->abortCount < rxi_callAbortThreshhold) {
        if (call->delayedAbortEvent) {
            rxevent_Cancel(call->delayedAbortEvent, call,
                           RX_CALL_REFCOUNT_ABORT);
        }
        error = htonl(call->error);
        call->abortCount++;
        packet =
            rxi_SendSpecial(call, call->conn, packet, RX_PACKET_TYPE_ABORT,
                            (char *)&error, sizeof(error), istack);
    } else if (!call->delayedAbortEvent) {
        clock_GetTime(&now);
        when = now;
        clock_Addmsec(&when, rxi_callAbortDelay);
        CALL_HOLD(call, RX_CALL_REFCOUNT_ABORT);
        call->delayedAbortEvent =
            rxevent_PostNow(&when, &now, rxi_SendDelayedCallAbort, call, 0);
    }
    return packet;
}

/* Send an abort packet for the specified connection.  Packet is an
 * optional pointer to a packet that can be used to send the abort.
 * Once the number of abort messages reaches the threshhold, an
 * event is scheduled to send the abort. Setting the force flag
 * overrides sending delayed abort messages.
 *
 * NOTE: Called with conn_data_lock held. conn_data_lock is dropped
 *       to send the abort packet.
 */
struct rx_packet *
rxi_SendConnectionAbort(struct rx_connection *conn,
                        struct rx_packet *packet, int istack, int force)
{
    afs_int32 error;
    struct clock when, now;

    if (!conn->error)
        return packet;

    /* Clients should never delay abort messages */
    if (rx_IsClientConn(conn))
        force = 1;

    if (force || rxi_connAbortThreshhold == 0
        || conn->abortCount < rxi_connAbortThreshhold) {
        if (conn->delayedAbortEvent) {
            rxevent_Cancel(conn->delayedAbortEvent, (struct rx_call *)0, 0);
        }
        error = htonl(conn->error);
        conn->abortCount++;
        MUTEX_EXIT(&conn->conn_data_lock);
        packet =
            rxi_SendSpecial((struct rx_call *)0, conn, packet,
                            RX_PACKET_TYPE_ABORT, (char *)&error,
                            sizeof(error), istack);
        MUTEX_ENTER(&conn->conn_data_lock);
    } else if (!conn->delayedAbortEvent) {
        clock_GetTime(&now);
        when = now;
        clock_Addmsec(&when, rxi_connAbortDelay);
        conn->delayedAbortEvent =
            rxevent_PostNow(&when, &now, rxi_SendDelayedConnAbort, conn, 0);
    }
    return packet;
}

/* Associate an error all of the calls owned by a connection.  Called
 * with error non-zero.  This is only for really fatal things, like
 * bad authentication responses.  The connection itself is set in
 * error at this point, so that future packets received will be
 * rejected. */
void
rxi_ConnectionError(struct rx_connection *conn,
                    afs_int32 error)
{
    if (error) {
        int i;

        dpf(("rxi_ConnectionError conn %"AFS_PTR_FMT" error %d", conn, error));

        MUTEX_ENTER(&conn->conn_data_lock);
        if (conn->challengeEvent)
            rxevent_Cancel(conn->challengeEvent, (struct rx_call *)0, 0);
        if (conn->natKeepAliveEvent)
            rxevent_Cancel(conn->natKeepAliveEvent, (struct rx_call *)0, 0);
        if (conn->checkReachEvent) {
            rxevent_Cancel(conn->checkReachEvent, (struct rx_call *)0, 0);
            conn->checkReachEvent = 0;
            conn->flags &= ~RX_CONN_ATTACHWAIT;
            conn->refCount--;
        }
        MUTEX_EXIT(&conn->conn_data_lock);
        for (i = 0; i < RX_MAXCALLS; i++) {
            struct rx_call *call = conn->call[i];
            if (call) {
                MUTEX_ENTER(&call->lock);
                rxi_CallError(call, error);
                MUTEX_EXIT(&call->lock);
            }
        }
        conn->error = error;
        if (rx_stats_active)
            rx_MutexIncrement(rx_stats.fatalErrors, rx_stats_mutex);
    }
}

void
rxi_CallError(struct rx_call *call, afs_int32 error)
{
#ifdef DEBUG
    osirx_AssertMine(&call->lock, "rxi_CallError");
#endif
    dpf(("rxi_CallError call %"AFS_PTR_FMT" error %d call->error %d", call, error, call->error));
    if (call->error)
        error = call->error;

#ifdef AFS_GLOBAL_RXLOCK_KERNEL
    if (!((call->flags & RX_CALL_TQ_BUSY) || (call->tqWaiters > 0))) {
        rxi_ResetCall(call, 0);
    }
#else
    rxi_ResetCall(call, 0);
#endif
    call->error = error;
    call->mode = RX_MODE_ERROR;
}

/* Reset various fields in a call structure, and wakeup waiting
 * processes.  Some fields aren't changed: state & mode are not
 * touched (these must be set by the caller), and bufptr, nLeft, and
 * nFree are not reset, since these fields are manipulated by
 * unprotected macros, and may only be reset by non-interrupting code.
 */
#ifdef ADAPT_WINDOW
/* this code requires that call->conn be set properly as a pre-condition. */
#endif /* ADAPT_WINDOW */

void
rxi_ResetCall(struct rx_call *call, int newcall)
{
    int flags;
    struct rx_peer *peer;
    struct rx_packet *packet;
#ifdef DEBUG
    osirx_AssertMine(&call->lock, "rxi_ResetCall");
#endif
    dpf(("rxi_ResetCall(call %"AFS_PTR_FMT", newcall %d)\n", call, newcall));

    /* Notify anyone who is waiting for asynchronous packet arrival */
    if (call->arrivalProc) {
        (*call->arrivalProc) (call, call->arrivalProcHandle,
                              call->arrivalProcArg);
        call->arrivalProc = (void (*)())0;
    }

    if (call->delayedAbortEvent) {
        rxevent_Cancel(call->delayedAbortEvent, call, RX_CALL_REFCOUNT_ABORT);
        packet = rxi_AllocPacket(RX_PACKET_CLASS_SPECIAL);
        if (packet) {
            rxi_SendCallAbort(call, packet, 0, 1);
            rxi_FreePacket(packet);
        }
    }

    /*
     * Update the peer with the congestion information in this call
     * so other calls on this connection can pick up where this call
     * left off. If the congestion sequence numbers don't match then
     * another call experienced a retransmission.
     */
    peer = call->conn->peer;
    MUTEX_ENTER(&peer->peer_lock);
    if (!newcall) {
        if (call->congestSeq == peer->congestSeq) {
            peer->cwind = MAX(peer->cwind, call->cwind);
            peer->MTU = MAX(peer->MTU, call->MTU);
            peer->nDgramPackets =
                MAX(peer->nDgramPackets, call->nDgramPackets);
        }
    } else {
        call->abortCode = 0;
        call->abortCount = 0;
    }
    if (peer->maxDgramPackets > 1) {
        call->MTU = RX_HEADER_SIZE + RX_JUMBOBUFFERSIZE;
    } else {
        call->MTU = peer->MTU;
    }
    call->cwind = MIN((int)peer->cwind, (int)peer->nDgramPackets);
    call->ssthresh = rx_maxSendWindow;
    call->nDgramPackets = peer->nDgramPackets;
    call->congestSeq = peer->congestSeq;
    MUTEX_EXIT(&peer->peer_lock);

    flags = call->flags;
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
    if (flags & RX_CALL_TQ_BUSY) {
        call->flags = RX_CALL_TQ_CLEARME | RX_CALL_TQ_BUSY;
        call->flags |= (flags & RX_CALL_TQ_WAIT);
        call->tqWaiters++;
#ifdef RX_ENABLE_LOCKS
        CV_WAIT(&call->cv_tq, &call->lock);
#else /* RX_ENABLE_LOCKS */
        osi_rxSleep(&call->tq);
#endif /* RX_ENABLE_LOCKS */
        call->tqWaiters--;
        if (call->tqWaiters == 0)
            call->flags &= ~RX_CALL_TQ_WAIT;
    } else
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
    {
        rxi_ClearTransmitQueue(call, 1);
        /* why init the queue if you just emptied it? queue_Init(&call->tq); */
        if (call->tqWaiters || (flags & RX_CALL_TQ_WAIT)) {
            dpf(("rcall %"AFS_PTR_FMT" has %d waiters and flags %d\n", call, call->tqWaiters, call->flags));
        }
        call->flags = 0;
    }

    rxi_ClearReceiveQueue(call);
    /* why init the queue if you just emptied it? queue_Init(&call->rq); */
    
    if (call->currentPacket) {
        call->currentPacket->flags &= ~RX_PKTFLAG_CP;
        call->currentPacket->flags |= RX_PKTFLAG_IOVQ;
        queue_Prepend(&call->iovq, call->currentPacket);
#ifdef RXDEBUG_PACKET
        call->iovqc++;
#endif /* RXDEBUG_PACKET */
        call->currentPacket = (struct rx_packet *)0;
    }
    call->curlen = call->nLeft = call->nFree = 0;

#ifdef RXDEBUG_PACKET
    call->iovqc -= 
#endif
        rxi_FreePackets(0, &call->iovq);

    call->error = 0;
    call->twind = call->conn->twind[call->channel];
    call->rwind = call->conn->rwind[call->channel];
    call->nSoftAcked = 0;
    call->nextCwind = 0;
    call->nAcks = 0;
    call->nNacks = 0;
    call->nCwindAcks = 0;
    call->nSoftAcks = 0;
    call->nHardAcks = 0;

    call->tfirst = call->rnext = call->tnext = 1;
    call->rprev = 0;
    call->lastAcked = 0;
    call->localStatus = call->remoteStatus = 0;

    if (flags & RX_CALL_READER_WAIT) {
#ifdef  RX_ENABLE_LOCKS
        CV_BROADCAST(&call->cv_rq);
#else
        osi_rxWakeup(&call->rq);
#endif
    }
    if (flags & RX_CALL_WAIT_PACKETS) {
        MUTEX_ENTER(&rx_freePktQ_lock);
        rxi_PacketsUnWait();    /* XXX */
        MUTEX_EXIT(&rx_freePktQ_lock);
    }
#ifdef  RX_ENABLE_LOCKS
    CV_SIGNAL(&call->cv_twind);
#else
    if (flags & RX_CALL_WAIT_WINDOW_ALLOC)
        osi_rxWakeup(&call->twind);
#endif

#ifdef RX_ENABLE_LOCKS
    /* The following ensures that we don't mess with any queue while some
     * other thread might also be doing so. The call_queue_lock field is
     * is only modified under the call lock. If the call is in the process
     * of being removed from a queue, the call is not locked until the
     * the queue lock is dropped and only then is the call_queue_lock field
     * zero'd out. So it's safe to lock the queue if call_queue_lock is set.
     * Note that any other routine which removes a call from a queue has to
     * obtain the queue lock before examing the queue and removing the call.
     */
    if (call->call_queue_lock) {
        MUTEX_ENTER(call->call_queue_lock);
        if (queue_IsOnQueue(call)) {
            queue_Remove(call);
            if (flags & RX_CALL_WAIT_PROC) {
                
                MUTEX_ENTER(&rx_waiting_mutex);
                rx_nWaiting--;
                MUTEX_EXIT(&rx_waiting_mutex);
            }
        }
        MUTEX_EXIT(call->call_queue_lock);
        CLEAR_CALL_QUEUE_LOCK(call);
    }
#else /* RX_ENABLE_LOCKS */
    if (queue_IsOnQueue(call)) {
        queue_Remove(call);
        if (flags & RX_CALL_WAIT_PROC)
            rx_nWaiting--;
    }
#endif /* RX_ENABLE_LOCKS */

    rxi_KeepAliveOff(call);
    rxevent_Cancel(call->delayedAckEvent, call, RX_CALL_REFCOUNT_DELAY);
}

/* Send an acknowledge for the indicated packet (seq,serial) of the
 * indicated call, for the indicated reason (reason).  This
 * acknowledge will specifically acknowledge receiving the packet, and
 * will also specify which other packets for this call have been
 * received.  This routine returns the packet that was used to the
 * caller.  The caller is responsible for freeing it or re-using it.
 * This acknowledgement also returns the highest sequence number
 * actually read out by the higher level to the sender; the sender
 * promises to keep around packets that have not been read by the
 * higher level yet (unless, of course, the sender decides to abort
 * the call altogether).  Any of p, seq, serial, pflags, or reason may
 * be set to zero without ill effect.  That is, if they are zero, they
 * will not convey any information.  
 * NOW there is a trailer field, after the ack where it will safely be
 * ignored by mundanes, which indicates the maximum size packet this 
 * host can swallow.  */
/*
    struct rx_packet *optionalPacket;  use to send ack (or null) 
    int seq;                     Sequence number of the packet we are acking 
    int serial;                  Serial number of the packet 
    int pflags;                  Flags field from packet header 
    int reason;                  Reason an acknowledge was prompted 
*/

struct rx_packet *
rxi_SendAck(struct rx_call *call,
            struct rx_packet *optionalPacket, int serial, int reason,
            int istack)
{
    struct rx_ackPacket *ap;
    struct rx_packet *rqp;
    struct rx_packet *nxp;      /* For queue_Scan */
    struct rx_packet *p;
    u_char offset;
    afs_int32 templ;
#ifdef RX_ENABLE_TSFPQ
    struct rx_ts_info_t * rx_ts_info;
#endif

    /*
     * Open the receive window once a thread starts reading packets
     */
    if (call->rnext > 1) {
        call->conn->rwind[call->channel] = call->rwind = rx_maxReceiveWindow;
    }

    call->nHardAcks = 0;
    call->nSoftAcks = 0;
    if (call->rnext > call->lastAcked)
        call->lastAcked = call->rnext;
    p = optionalPacket;

    if (p) {
        rx_computelen(p, p->length);    /* reset length, you never know */
    } /* where that's been...         */
#ifdef RX_ENABLE_TSFPQ
    else {
        RX_TS_INFO_GET(rx_ts_info);
        if ((p = rx_ts_info->local_special_packet)) {
            rx_computelen(p, p->length);
        } else if ((p = rxi_AllocPacket(RX_PACKET_CLASS_SPECIAL))) {
            rx_ts_info->local_special_packet = p;
        } else { /* We won't send the ack, but don't panic. */
            return optionalPacket;
        }
    }
#else
    else if (!(p = rxi_AllocPacket(RX_PACKET_CLASS_SPECIAL))) {
        /* We won't send the ack, but don't panic. */
        return optionalPacket;
    }
#endif

    templ =
        rx_AckDataSize(call->rwind) + 4 * sizeof(afs_int32) -
        rx_GetDataSize(p);
    if (templ > 0) {
        if (rxi_AllocDataBuf(p, templ, RX_PACKET_CLASS_SPECIAL) > 0) {
#ifndef RX_ENABLE_TSFPQ
            if (!optionalPacket)
                rxi_FreePacket(p);
#endif
            return optionalPacket;
        }
        templ = rx_AckDataSize(call->rwind) + 2 * sizeof(afs_int32);
        if (rx_Contiguous(p) < templ) {
#ifndef RX_ENABLE_TSFPQ
            if (!optionalPacket)
                rxi_FreePacket(p);
#endif
            return optionalPacket;
        }
    }


    /* MTUXXX failing to send an ack is very serious.  We should */
    /* try as hard as possible to send even a partial ack; it's */
    /* better than nothing. */
    ap = (struct rx_ackPacket *)rx_DataOf(p);
    ap->bufferSpace = htonl(0); /* Something should go here, sometime */
    ap->reason = reason;

    /* The skew computation used to be bogus, I think it's better now. */
    /* We should start paying attention to skew.    XXX  */
    ap->serial = htonl(serial);
    ap->maxSkew = 0;            /* used to be peer->inPacketSkew */

    ap->firstPacket = htonl(call->rnext);       /* First packet not yet forwarded to reader */
    ap->previousPacket = htonl(call->rprev);    /* Previous packet received */

    /* No fear of running out of ack packet here because there can only be at most
     * one window full of unacknowledged packets.  The window size must be constrained 
     * to be less than the maximum ack size, of course.  Also, an ack should always
     * fit into a single packet -- it should not ever be fragmented.  */
    for (offset = 0, queue_Scan(&call->rq, rqp, nxp, rx_packet)) {
        if (!rqp || !call->rq.next
            || (rqp->header.seq > (call->rnext + call->rwind))) {
#ifndef RX_ENABLE_TSFPQ
            if (!optionalPacket)
                rxi_FreePacket(p);
#endif
            rxi_CallError(call, RX_CALL_DEAD);
            return optionalPacket;
        }

        while (rqp->header.seq > call->rnext + offset)
            ap->acks[offset++] = RX_ACK_TYPE_NACK;
        ap->acks[offset++] = RX_ACK_TYPE_ACK;

        if ((offset > (u_char) rx_maxReceiveWindow) || (offset > call->rwind)) {
#ifndef RX_ENABLE_TSFPQ
            if (!optionalPacket)
                rxi_FreePacket(p);
#endif
            rxi_CallError(call, RX_CALL_DEAD);
            return optionalPacket;
        }
    }

    ap->nAcks = offset;
    p->length = rx_AckDataSize(offset) + 4 * sizeof(afs_int32);

    /* these are new for AFS 3.3 */
    templ = rxi_AdjustMaxMTU(call->conn->peer->ifMTU, rx_maxReceiveSize);
    templ = htonl(templ);
    rx_packetwrite(p, rx_AckDataSize(offset), sizeof(afs_int32), &templ);
    templ = htonl(call->conn->peer->ifMTU);
    rx_packetwrite(p, rx_AckDataSize(offset) + sizeof(afs_int32),
                   sizeof(afs_int32), &templ);

    /* new for AFS 3.4 */
    templ = htonl(call->rwind);
    rx_packetwrite(p, rx_AckDataSize(offset) + 2 * sizeof(afs_int32),
                   sizeof(afs_int32), &templ);

    /* new for AFS 3.5 */
    templ = htonl(call->conn->peer->ifDgramPackets);
    rx_packetwrite(p, rx_AckDataSize(offset) + 3 * sizeof(afs_int32),
                   sizeof(afs_int32), &templ);

    p->header.serviceId = call->conn->serviceId;
    p->header.cid = (call->conn->cid | call->channel);
    p->header.callNumber = *call->callNumber;
    p->header.seq = 0;
    p->header.securityIndex = call->conn->securityIndex;
    p->header.epoch = call->conn->epoch;
    p->header.type = RX_PACKET_TYPE_ACK;
    p->header.flags = RX_SLOW_START_OK;
    if (reason == RX_ACK_PING) {
        p->header.flags |= RX_REQUEST_ACK;
#ifdef ADAPT_WINDOW
        clock_GetTime(&call->pingRequestTime);
#endif
    }
    if (call->conn->type == RX_CLIENT_CONNECTION)
        p->header.flags |= RX_CLIENT_INITIATED;

#ifdef RXDEBUG
#ifdef AFS_NT40_ENV
    if (rxdebug_active) {
        char msg[512];
        size_t len;

        len = _snprintf(msg, sizeof(msg),
                        "tid[%d] SACK: reason %s serial %u previous %u seq %u first %u acks %u space %u ",
                         GetCurrentThreadId(), rx_ack_reason(ap->reason), 
                         ntohl(ap->serial), ntohl(ap->previousPacket),
                         (unsigned int)p->header.seq, ntohl(ap->firstPacket),
                         ap->nAcks, ntohs(ap->bufferSpace) );
        if (ap->nAcks) {
            int offset;

            for (offset = 0; offset < ap->nAcks && len < sizeof(msg); offset++) 
                msg[len++] = (ap->acks[offset] == RX_ACK_TYPE_NACK ? '-' : '*');
        }
        msg[len++]='\n';
        msg[len] = '\0';
        OutputDebugString(msg);
    }
#else /* AFS_NT40_ENV */
    if (rx_Log) {
        fprintf(rx_Log, "SACK: reason %x previous %u seq %u first %u ",
                ap->reason, ntohl(ap->previousPacket),
                (unsigned int)p->header.seq, ntohl(ap->firstPacket));
        if (ap->nAcks) {
            for (offset = 0; offset < ap->nAcks; offset++)
                putc(ap->acks[offset] == RX_ACK_TYPE_NACK ? '-' : '*',
                     rx_Log);
        }
        putc('\n', rx_Log);
    }
#endif /* AFS_NT40_ENV */
#endif
    {
        int i, nbytes = p->length;

        for (i = 1; i < p->niovecs; i++) {      /* vec 0 is ALWAYS header */
            if (nbytes <= p->wirevec[i].iov_len) {
                int savelen, saven;

                savelen = p->wirevec[i].iov_len;
                saven = p->niovecs;
                p->wirevec[i].iov_len = nbytes;
                p->niovecs = i + 1;
                rxi_Send(call, p, istack);
                p->wirevec[i].iov_len = savelen;
                p->niovecs = saven;
                break;
            } else
                nbytes -= p->wirevec[i].iov_len;
        }
    }
    if (rx_stats_active)
        rx_MutexIncrement(rx_stats.ackPacketsSent, rx_stats_mutex);
#ifndef RX_ENABLE_TSFPQ
    if (!optionalPacket)
        rxi_FreePacket(p);
#endif
    return optionalPacket;      /* Return packet for re-use by caller */
}

/* Send all of the packets in the list in single datagram */
static void
rxi_SendList(struct rx_call *call, struct rx_packet **list, int len,
             int istack, int moreFlag, struct clock *now,
             struct clock *retryTime, int resending)
{
    int i;
    int requestAck = 0;
    int lastPacket = 0;
    struct rx_connection *conn = call->conn;
    struct rx_peer *peer = conn->peer;

    MUTEX_ENTER(&peer->peer_lock);
    peer->nSent += len;
    if (resending)
        peer->reSends += len;
    if (rx_stats_active)
        rx_MutexAdd(rx_stats.dataPacketsSent, len, rx_stats_mutex);
    MUTEX_EXIT(&peer->peer_lock);

    if (list[len - 1]->header.flags & RX_LAST_PACKET) {
        lastPacket = 1;
    }

    /* Set the packet flags and schedule the resend events */
    /* Only request an ack for the last packet in the list */
    for (i = 0; i < len; i++) {
        list[i]->retryTime = *retryTime;
        if (list[i]->header.serial) {
            /* Exponentially backoff retry times */
            if (list[i]->backoff < MAXBACKOFF) {
                /* so it can't stay == 0 */
                list[i]->backoff = (list[i]->backoff << 1) + 1;
            } else
                list[i]->backoff++;
            clock_Addmsec(&(list[i]->retryTime),
                          ((afs_uint32) list[i]->backoff) << 8);
        }

        /* Wait a little extra for the ack on the last packet */
        if (lastPacket && !(list[i]->header.flags & RX_CLIENT_INITIATED)) {
            clock_Addmsec(&(list[i]->retryTime), 400);
        }

        /* Record the time sent */
        list[i]->timeSent = *now;

        /* Ask for an ack on retransmitted packets,  on every other packet
         * if the peer doesn't support slow start. Ask for an ack on every
         * packet until the congestion window reaches the ack rate. */
        if (list[i]->header.serial) {
            requestAck = 1;
            if (rx_stats_active)
                rx_MutexIncrement(rx_stats.dataPacketsReSent, rx_stats_mutex);
        } else {
            /* improved RTO calculation- not Karn */
            list[i]->firstSent = *now;
            if (!lastPacket && (call->cwind <= (u_short) (conn->ackRate + 1)
                                || (!(call->flags & RX_CALL_SLOW_START_OK)
                                    && (list[i]->header.seq & 1)))) {
                requestAck = 1;
            }
        }

        /* Tag this packet as not being the last in this group,
         * for the receiver's benefit */
        if (i < len - 1 || moreFlag) {
            list[i]->header.flags |= RX_MORE_PACKETS;
        }

        /* Install the new retransmit time for the packet, and
         * record the time sent */
        list[i]->timeSent = *now;
    }

    if (requestAck) {
        list[len - 1]->header.flags |= RX_REQUEST_ACK;
    }

    /* Since we're about to send a data packet to the peer, it's
     * safe to nuke any scheduled end-of-packets ack */
    rxevent_Cancel(call->delayedAckEvent, call, RX_CALL_REFCOUNT_DELAY);

    CALL_HOLD(call, RX_CALL_REFCOUNT_SEND);
    MUTEX_EXIT(&call->lock);
    if (len > 1) {
        rxi_SendPacketList(call, conn, list, len, istack);
    } else {
        rxi_SendPacket(call, conn, list[0], istack);
    }
    MUTEX_ENTER(&call->lock);
    CALL_RELE(call, RX_CALL_REFCOUNT_SEND);

    /* Update last send time for this call (for keep-alive
     * processing), and for the connection (so that we can discover
     * idle connections) */
    call->lastSendData = conn->lastSendTime = call->lastSendTime = clock_Sec();
}

/* When sending packets we need to follow these rules:
 * 1. Never send more than maxDgramPackets in a jumbogram.
 * 2. Never send a packet with more than two iovecs in a jumbogram.
 * 3. Never send a retransmitted packet in a jumbogram.
 * 4. Never send more than cwind/4 packets in a jumbogram
 * We always keep the last list we should have sent so we
 * can set the RX_MORE_PACKETS flags correctly.
 */
static void
rxi_SendXmitList(struct rx_call *call, struct rx_packet **list, int len,
                 int istack, struct clock *now, struct clock *retryTime,
                 int resending)
{
    int i, cnt, lastCnt = 0;
    struct rx_packet **listP, **lastP = 0;
    struct rx_peer *peer = call->conn->peer;
    int morePackets = 0;

    for (cnt = 0, listP = &list[0], i = 0; i < len; i++) {
        /* Does the current packet force us to flush the current list? */
        if (cnt > 0
            && (list[i]->header.serial || (list[i]->flags & RX_PKTFLAG_ACKED)
                || list[i]->length > RX_JUMBOBUFFERSIZE)) {
            if (lastCnt > 0) {
                rxi_SendList(call, lastP, lastCnt, istack, 1, now, retryTime,
                             resending);
                /* If the call enters an error state stop sending, or if
                 * we entered congestion recovery mode, stop sending */
                if (call->error || (call->flags & RX_CALL_FAST_RECOVER_WAIT))
                    return;
            }
            lastP = listP;
            lastCnt = cnt;
            listP = &list[i];
            cnt = 0;
        }
        /* Add the current packet to the list if it hasn't been acked.
         * Otherwise adjust the list pointer to skip the current packet.  */
        if (!(list[i]->flags & RX_PKTFLAG_ACKED)) {
            cnt++;
            /* Do we need to flush the list? */
            if (cnt >= (int)peer->maxDgramPackets
                || cnt >= (int)call->nDgramPackets || cnt >= (int)call->cwind
                || list[i]->header.serial
                || list[i]->length != RX_JUMBOBUFFERSIZE) {
                if (lastCnt > 0) {
                    rxi_SendList(call, lastP, lastCnt, istack, 1, now,
                                 retryTime, resending);
                    /* If the call enters an error state stop sending, or if
                     * we entered congestion recovery mode, stop sending */
                    if (call->error
                        || (call->flags & RX_CALL_FAST_RECOVER_WAIT))
                        return;
                }
                lastP = listP;
                lastCnt = cnt;
                listP = &list[i + 1];
                cnt = 0;
            }
        } else {
            if (cnt != 0) {
                osi_Panic("rxi_SendList error");
            }
            listP = &list[i + 1];
        }
    }

    /* Send the whole list when the call is in receive mode, when
     * the call is in eof mode, when we are in fast recovery mode,
     * and when we have the last packet */
    if ((list[len - 1]->header.flags & RX_LAST_PACKET)
        || call->mode == RX_MODE_RECEIVING || call->mode == RX_MODE_EOF
        || (call->flags & RX_CALL_FAST_RECOVER)) {
        /* Check for the case where the current list contains
         * an acked packet. Since we always send retransmissions
         * in a separate packet, we only need to check the first
         * packet in the list */
        if (cnt > 0 && !(listP[0]->flags & RX_PKTFLAG_ACKED)) {
            morePackets = 1;
        }
        if (lastCnt > 0) {
            rxi_SendList(call, lastP, lastCnt, istack, morePackets, now,
                         retryTime, resending);
            /* If the call enters an error state stop sending, or if
             * we entered congestion recovery mode, stop sending */
            if (call->error || (call->flags & RX_CALL_FAST_RECOVER_WAIT))
                return;
        }
        if (morePackets) {
            rxi_SendList(call, listP, cnt, istack, 0, now, retryTime,
                         resending);
        }
    } else if (lastCnt > 0) {
        rxi_SendList(call, lastP, lastCnt, istack, 0, now, retryTime,
                     resending);
    }
}

#ifdef  RX_ENABLE_LOCKS
/* Call rxi_Start, below, but with the call lock held. */
void
rxi_StartUnlocked(struct rxevent *event, 
                  void *arg0, void *arg1, int istack)
{
    struct rx_call *call = arg0;
    
    MUTEX_ENTER(&call->lock);
    rxi_Start(event, call, arg1, istack);
    MUTEX_EXIT(&call->lock);
}
#endif /* RX_ENABLE_LOCKS */

/* This routine is called when new packets are readied for
 * transmission and when retransmission may be necessary, or when the
 * transmission window or burst count are favourable.  This should be
 * better optimized for new packets, the usual case, now that we've
 * got rid of queues of send packets. XXXXXXXXXXX */
void
rxi_Start(struct rxevent *event, 
          void *arg0, void *arg1, int istack)
{
    struct rx_call *call = arg0;
    
    struct rx_packet *p;
    struct rx_packet *nxp;      /* Next pointer for queue_Scan */
    struct rx_peer *peer = call->conn->peer;
    struct clock now, usenow, retryTime;
    int haveEvent;
    int nXmitPackets;
    int maxXmitPackets;
    struct rx_packet **xmitList;
    int resending = 0;

    /* If rxi_Start is being called as a result of a resend event,
     * then make sure that the event pointer is removed from the call
     * structure, since there is no longer a per-call retransmission
     * event pending. */
    if (event && event == call->resendEvent) {
        CALL_RELE(call, RX_CALL_REFCOUNT_RESEND);
        call->resendEvent = NULL;
        resending = 1;
        if (queue_IsEmpty(&call->tq)) {
            /* Nothing to do */
            return;
        }
        /* Timeouts trigger congestion recovery */
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
        if (call->flags & RX_CALL_FAST_RECOVER_WAIT) {
            /* someone else is waiting to start recovery */
            return;
        }
        call->flags |= RX_CALL_FAST_RECOVER_WAIT;
        rxi_WaitforTQBusy(call);
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
        call->flags &= ~RX_CALL_FAST_RECOVER_WAIT;
        call->flags |= RX_CALL_FAST_RECOVER;
        if (peer->maxDgramPackets > 1) {
            call->MTU = RX_JUMBOBUFFERSIZE + RX_HEADER_SIZE;
        } else {
            call->MTU = MIN(peer->natMTU, peer->maxMTU);
        }
        call->ssthresh = MAX(4, MIN((int)call->cwind, (int)call->twind)) >> 1;
        call->nDgramPackets = 1;
        call->cwind = 1;
        call->nextCwind = 1;
        call->nAcks = 0;
        call->nNacks = 0;
        MUTEX_ENTER(&peer->peer_lock);
        peer->MTU = call->MTU;
        peer->cwind = call->cwind;
        peer->nDgramPackets = 1;
        peer->congestSeq++;
        call->congestSeq = peer->congestSeq;
        MUTEX_EXIT(&peer->peer_lock);
        /* Clear retry times on packets. Otherwise, it's possible for
         * some packets in the queue to force resends at rates faster
         * than recovery rates.
         */
        for (queue_Scan(&call->tq, p, nxp, rx_packet)) {
            if (!(p->flags & RX_PKTFLAG_ACKED)) {
                clock_Zero(&p->retryTime);
            }
        }
    }
    if (call->error) {
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
        if (rx_stats_active)
            rx_MutexIncrement(rx_tq_debug.rxi_start_in_error, rx_stats_mutex);
#endif
        return;
    }

    if (queue_IsNotEmpty(&call->tq)) {  /* If we have anything to send */
        /* Get clock to compute the re-transmit time for any packets
         * in this burst.  Note, if we back off, it's reasonable to
         * back off all of the packets in the same manner, even if
         * some of them have been retransmitted more times than more
         * recent additions.
         * Do a dance to avoid blocking after setting now. */
        MUTEX_ENTER(&peer->peer_lock);
        retryTime = peer->timeout;
        MUTEX_EXIT(&peer->peer_lock);
        clock_GetTime(&now);
        clock_Add(&retryTime, &now);
        usenow = now;
        /* Send (or resend) any packets that need it, subject to
         * window restrictions and congestion burst control
         * restrictions.  Ask for an ack on the last packet sent in
         * this burst.  For now, we're relying upon the window being
         * considerably bigger than the largest number of packets that
         * are typically sent at once by one initial call to
         * rxi_Start.  This is probably bogus (perhaps we should ask
         * for an ack when we're half way through the current
         * window?).  Also, for non file transfer applications, this
         * may end up asking for an ack for every packet.  Bogus. XXXX
         */
        /*
         * But check whether we're here recursively, and let the other guy
         * do the work.
         */
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
        if (!(call->flags & RX_CALL_TQ_BUSY)) {
            call->flags |= RX_CALL_TQ_BUSY;
            do {
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
            restart:
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
                call->flags &= ~RX_CALL_NEED_START;
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
                nXmitPackets = 0;
                maxXmitPackets = MIN(call->twind, call->cwind);
                xmitList = (struct rx_packet **)
#if defined(KERNEL) && !defined(UKERNEL) && defined(AFS_FBSD80_ENV)
                    /* XXXX else we must drop any mtx we hold */
                    afs_osi_Alloc_NoSleep(maxXmitPackets * sizeof(struct rx_packet *));
#else
                osi_Alloc(maxXmitPackets * sizeof(struct rx_packet *));
#endif
                if (xmitList == NULL)
                    osi_Panic("rxi_Start, failed to allocate xmit list");
                for (queue_Scan(&call->tq, p, nxp, rx_packet)) {
                    if (call->flags & RX_CALL_FAST_RECOVER_WAIT) {
                        /* We shouldn't be sending packets if a thread is waiting
                         * to initiate congestion recovery */
                        dpf(("call %d waiting to initiate fast recovery\n",
                             *(call->callNumber)));
                        break;
                    }
                    if ((nXmitPackets)
                        && (call->flags & RX_CALL_FAST_RECOVER)) {
                        /* Only send one packet during fast recovery */
                        dpf(("call %d restricted to one packet per send during fast recovery\n",
                             *(call->callNumber)));
                        break;
                    }
                    if ((p->flags & RX_PKTFLAG_FREE)
                        || (!queue_IsEnd(&call->tq, nxp)
                            && (nxp->flags & RX_PKTFLAG_FREE))
                        || (p == (struct rx_packet *)&rx_freePacketQueue)
                        || (nxp == (struct rx_packet *)&rx_freePacketQueue)) {
                        osi_Panic("rxi_Start: xmit queue clobbered");
                    }
                    if (p->flags & RX_PKTFLAG_ACKED) {
                        /* Since we may block, don't trust this */
                        usenow.sec = usenow.usec = 0;
                        if (rx_stats_active)
                            rx_MutexIncrement(rx_stats.ignoreAckedPacket, rx_stats_mutex);
                        continue;       /* Ignore this packet if it has been acknowledged */
                    }

                    /* Turn off all flags except these ones, which are the same
                     * on each transmission */
                    p->header.flags &= RX_PRESET_FLAGS;

                    if (p->header.seq >=
                        call->tfirst + MIN((int)call->twind,
                                           (int)(call->nSoftAcked +
                                                 call->cwind))) {
                        call->flags |= RX_CALL_WAIT_WINDOW_SEND;        /* Wait for transmit window */
                        /* Note: if we're waiting for more window space, we can
                         * still send retransmits; hence we don't return here, but
                         * break out to schedule a retransmit event */
                        dpf(("call %d waiting for window (seq %d, twind %d, nSoftAcked %d, cwind %d)\n",
                             *(call->callNumber), p->header.seq, call->twind, call->nSoftAcked,
                             call->cwind));
                        break;
                    }

                    /* Transmit the packet if it needs to be sent. */
                    if (!clock_Lt(&now, &p->retryTime)) {
                        if (nXmitPackets == maxXmitPackets) {
                            rxi_SendXmitList(call, xmitList, nXmitPackets, 
                                             istack, &now, &retryTime, 
                                             resending);
                            osi_Free(xmitList, maxXmitPackets * 
                                     sizeof(struct rx_packet *));
                            goto restart;
                        }
                        dpf(("call %d xmit packet %"AFS_PTR_FMT" now %u.%06u retryTime %u.%06u nextRetry %u.%06u\n",
                              *(call->callNumber), p,
                              now.sec, now.usec,
                              p->retryTime.sec, p->retryTime.usec,
                              retryTime.sec, retryTime.usec));
                        xmitList[nXmitPackets++] = p;
                    }
                }

                /* xmitList now hold pointers to all of the packets that are
                 * ready to send. Now we loop to send the packets */
                if (nXmitPackets > 0) {
                    rxi_SendXmitList(call, xmitList, nXmitPackets, istack,
                                     &now, &retryTime, resending);
                }
                osi_Free(xmitList,
                         maxXmitPackets * sizeof(struct rx_packet *));

#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
                /*
                 * TQ references no longer protected by this flag; they must remain
                 * protected by the global lock.
                 */
                if (call->flags & RX_CALL_FAST_RECOVER_WAIT) {
                    call->flags &= ~RX_CALL_TQ_BUSY;
                    if (call->tqWaiters || (call->flags & RX_CALL_TQ_WAIT)) {
                        dpf(("call %"AFS_PTR_FMT" has %d waiters and flags %d\n",
                             call, call->tqWaiters, call->flags));
#ifdef RX_ENABLE_LOCKS
                        osirx_AssertMine(&call->lock, "rxi_Start start");
                        CV_BROADCAST(&call->cv_tq);
#else /* RX_ENABLE_LOCKS */
                        osi_rxWakeup(&call->tq);
#endif /* RX_ENABLE_LOCKS */
                    }
                    return;
                }
                if (call->error) {
                    /* We went into the error state while sending packets. Now is
                     * the time to reset the call. This will also inform the using
                     * process that the call is in an error state.
                     */
                    if (rx_stats_active)
                        rx_MutexIncrement(rx_tq_debug.rxi_start_aborted, rx_stats_mutex);
                    call->flags &= ~RX_CALL_TQ_BUSY;
                    if (call->tqWaiters || (call->flags & RX_CALL_TQ_WAIT)) {
                        dpf(("call error %d while xmit %p has %d waiters and flags %d\n",
                             call->error, call, call->tqWaiters, call->flags));
#ifdef RX_ENABLE_LOCKS
                        osirx_AssertMine(&call->lock, "rxi_Start middle");
                        CV_BROADCAST(&call->cv_tq);
#else /* RX_ENABLE_LOCKS */
                        osi_rxWakeup(&call->tq);
#endif /* RX_ENABLE_LOCKS */
                    }
                    rxi_CallError(call, call->error);
                    return;
                }
#ifdef RX_ENABLE_LOCKS
                if (call->flags & RX_CALL_TQ_SOME_ACKED) {
                    int missing;
                    call->flags &= ~RX_CALL_TQ_SOME_ACKED;
                    /* Some packets have received acks. If they all have, we can clear
                     * the transmit queue.
                     */
                    for (missing =
                         0, queue_Scan(&call->tq, p, nxp, rx_packet)) {
                        if (p->header.seq < call->tfirst
                            && (p->flags & RX_PKTFLAG_ACKED)) {
                            queue_Remove(p);
                            p->flags &= ~RX_PKTFLAG_TQ;
#ifdef RXDEBUG_PACKET
                            call->tqc--;
#endif
                            rxi_FreePacket(p);
                        } else
                            missing = 1;
                    }
                    if (!missing)
                        call->flags |= RX_CALL_TQ_CLEARME;
                }
#endif /* RX_ENABLE_LOCKS */
                /* Don't bother doing retransmits if the TQ is cleared. */
                if (call->flags & RX_CALL_TQ_CLEARME) {
                    rxi_ClearTransmitQueue(call, 1);
                } else
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
                {

                    /* Always post a resend event, if there is anything in the
                     * queue, and resend is possible.  There should be at least
                     * one unacknowledged packet in the queue ... otherwise none
                     * of these packets should be on the queue in the first place.
                     */
                    if (call->resendEvent) {
                        /* Cancel the existing event and post a new one */
                        rxevent_Cancel(call->resendEvent, call,
                                       RX_CALL_REFCOUNT_RESEND);
                    }

                    /* The retry time is the retry time on the first unacknowledged
                     * packet inside the current window */
                    for (haveEvent =
                         0, queue_Scan(&call->tq, p, nxp, rx_packet)) {
                        /* Don't set timers for packets outside the window */
                        if (p->header.seq >= call->tfirst + call->twind) {
                            break;
                        }

                        if (!(p->flags & RX_PKTFLAG_ACKED)
                            && !clock_IsZero(&p->retryTime)) {
                            haveEvent = 1;
                            retryTime = p->retryTime;
                            break;
                        }
                    }

                    /* Post a new event to re-run rxi_Start when retries may be needed */
                    if (haveEvent && !(call->flags & RX_CALL_NEED_START)) {
#ifdef RX_ENABLE_LOCKS
                        CALL_HOLD(call, RX_CALL_REFCOUNT_RESEND);
                        call->resendEvent =
                            rxevent_PostNow2(&retryTime, &usenow, 
                                             rxi_StartUnlocked,
                                             (void *)call, 0, istack);
#else /* RX_ENABLE_LOCKS */
                        call->resendEvent =
                            rxevent_PostNow2(&retryTime, &usenow, rxi_Start, 
                                             (void *)call, 0, istack);
#endif /* RX_ENABLE_LOCKS */
                    }
                }
#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
            } while (call->flags & RX_CALL_NEED_START);
            /*
             * TQ references no longer protected by this flag; they must remain
             * protected by the global lock.
             */
            call->flags &= ~RX_CALL_TQ_BUSY;
            if (call->tqWaiters || (call->flags & RX_CALL_TQ_WAIT)) {
                dpf(("call %"AFS_PTR_FMT" has %d waiters and flags %d\n",
                      call, call->tqWaiters, call->flags));
#ifdef RX_ENABLE_LOCKS
                osirx_AssertMine(&call->lock, "rxi_Start end");
                CV_BROADCAST(&call->cv_tq);
#else /* RX_ENABLE_LOCKS */
                osi_rxWakeup(&call->tq);
#endif /* RX_ENABLE_LOCKS */
            }
        } else {
            call->flags |= RX_CALL_NEED_START;
        }
#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
    } else {
        if (call->resendEvent) {
            rxevent_Cancel(call->resendEvent, call, RX_CALL_REFCOUNT_RESEND);
        }
    }
}

/* Also adjusts the keep alive parameters for the call, to reflect
 * that we have just sent a packet (so keep alives aren't sent
 * immediately) */
void
rxi_Send(struct rx_call *call, struct rx_packet *p,
         int istack)
{
    struct rx_connection *conn = call->conn;

    /* Stamp each packet with the user supplied status */
    p->header.userStatus = call->localStatus;

    /* Allow the security object controlling this call's security to
     * make any last-minute changes to the packet */
    RXS_SendPacket(conn->securityObject, call, p);

    /* Since we're about to send SOME sort of packet to the peer, it's
     * safe to nuke any scheduled end-of-packets ack */
    rxevent_Cancel(call->delayedAckEvent, call, RX_CALL_REFCOUNT_DELAY);

    /* Actually send the packet, filling in more connection-specific fields */
    CALL_HOLD(call, RX_CALL_REFCOUNT_SEND);
    MUTEX_EXIT(&call->lock);
    rxi_SendPacket(call, conn, p, istack);
    MUTEX_ENTER(&call->lock);
    CALL_RELE(call, RX_CALL_REFCOUNT_SEND);

    /* Update last send time for this call (for keep-alive
     * processing), and for the connection (so that we can discover
     * idle connections) */
    conn->lastSendTime = call->lastSendTime = clock_Sec();
    /* Don't count keepalives here, so idleness can be tracked. */
    if ((p->header.type != RX_PACKET_TYPE_ACK) || (((struct rx_ackPacket *)rx_DataOf(p))->reason != RX_ACK_PING))
        call->lastSendData = call->lastSendTime;
}


/* Check if a call needs to be destroyed.  Called by keep-alive code to ensure
 * that things are fine.  Also called periodically to guarantee that nothing
 * falls through the cracks (e.g. (error + dally) connections have keepalive
 * turned off.  Returns 0 if conn is well, -1 otherwise.  If otherwise, call
 *  may be freed!
 * haveCTLock Set if calling from rxi_ReapConnections
 */
#ifdef RX_ENABLE_LOCKS
int
rxi_CheckCall(struct rx_call *call, int haveCTLock)
#else /* RX_ENABLE_LOCKS */
int
rxi_CheckCall(struct rx_call *call)
#endif                          /* RX_ENABLE_LOCKS */
{
    struct rx_connection *conn = call->conn;
    afs_uint32 now;
    afs_uint32 deadTime;

#ifdef AFS_GLOBAL_RXLOCK_KERNEL
    if (call->flags & RX_CALL_TQ_BUSY) {
        /* Call is active and will be reset by rxi_Start if it's
         * in an error state.
         */
        return 0;
    }
#endif
    /* dead time + RTT + 8*MDEV, rounded up to next second. */
    deadTime =
        (((afs_uint32) conn->secondsUntilDead << 10) +
         ((afs_uint32) conn->peer->rtt >> 3) +
         ((afs_uint32) conn->peer->rtt_dev << 1) + 1023) >> 10;
    now = clock_Sec();
    /* These are computed to the second (+- 1 second).  But that's
     * good enough for these values, which should be a significant
     * number of seconds. */
    if (now > (call->lastReceiveTime + deadTime)) {
        if (call->state == RX_STATE_ACTIVE) {
#ifdef ADAPT_PMTU
#if defined(KERNEL) && defined(AFS_SUN57_ENV)
            ire_t *ire;
#if defined(AFS_SUN510_ENV) && defined(GLOBAL_NETSTACKID)
            netstack_t *ns =  netstack_find_by_stackid(GLOBAL_NETSTACKID);
            ip_stack_t *ipst = ns->netstack_ip;
#endif
            ire = ire_cache_lookup(call->conn->peer->host
#if defined(AFS_SUN510_ENV) && defined(ALL_ZONES)
                                   , ALL_ZONES
#if defined(AFS_SUN510_ENV) && (defined(ICL_3_ARG) || defined(GLOBAL_NETSTACKID))
                                   , NULL
#if defined(AFS_SUN510_ENV) && defined(GLOBAL_NETSTACKID)
                                   , ipst
#endif
#endif
#endif
                );
            
            if (ire && ire->ire_max_frag > 0)
                rxi_SetPeerMtu(call->conn->peer->host, 0, ire->ire_max_frag);
#if defined(GLOBAL_NETSTACKID)
            netstack_rele(ns);
#endif
#endif
#endif /* ADAPT_PMTU */
            rxi_CallError(call, RX_CALL_DEAD);
            return -1;
        } else {
#ifdef RX_ENABLE_LOCKS
            /* Cancel pending events */
            rxevent_Cancel(call->delayedAckEvent, call,
                           RX_CALL_REFCOUNT_DELAY);
            rxevent_Cancel(call->resendEvent, call, RX_CALL_REFCOUNT_RESEND);
            rxevent_Cancel(call->keepAliveEvent, call,
                           RX_CALL_REFCOUNT_ALIVE);
            if (call->refCount == 0) {
                rxi_FreeCall(call, haveCTLock);
                return -2;
            }
            return -1;
#else /* RX_ENABLE_LOCKS */
            rxi_FreeCall(call);
            return -2;
#endif /* RX_ENABLE_LOCKS */
        }
        /* Non-active calls are destroyed if they are not responding
         * to pings; active calls are simply flagged in error, so the
         * attached process can die reasonably gracefully. */
    }
    /* see if we have a non-activity timeout */
    if (call->startWait && conn->idleDeadTime
        && ((call->startWait + conn->idleDeadTime) < now) &&
        (call->flags & RX_CALL_READER_WAIT)) {
        if (call->state == RX_STATE_ACTIVE) {
            rxi_CallError(call, RX_CALL_TIMEOUT);
            return -1;
        }
    }
    if (call->lastSendData && conn->idleDeadTime && (conn->idleDeadErr != 0)
        && ((call->lastSendData + conn->idleDeadTime) < now)) {
        if (call->state == RX_STATE_ACTIVE) {
            rxi_CallError(call, conn->idleDeadErr);
            return -1;
        }
    }
    /* see if we have a hard timeout */
    if (conn->hardDeadTime
        && (now > (conn->hardDeadTime + call->startTime.sec))) {
        if (call->state == RX_STATE_ACTIVE)
            rxi_CallError(call, RX_CALL_TIMEOUT);
        return -1;
    }
    return 0;
}

void
rxi_NatKeepAliveEvent(struct rxevent *event, void *arg1, void *dummy)
{
    struct rx_connection *conn = arg1;
    struct rx_header theader;
    char tbuffer[1500];
    struct sockaddr_in taddr;
    char *tp;
    char a[1] = { 0 };
    struct iovec tmpiov[2];
    osi_socket socket =
        (conn->type ==
         RX_CLIENT_CONNECTION ? rx_socket : conn->service->socket);


    tp = &tbuffer[sizeof(struct rx_header)];
    taddr.sin_family = AF_INET;
    taddr.sin_port = rx_PortOf(rx_PeerOf(conn));
    taddr.sin_addr.s_addr = rx_HostOf(rx_PeerOf(conn));
#ifdef STRUCT_SOCKADDR_HAS_SA_LEN
    taddr.sin_len = sizeof(struct sockaddr_in);
#endif
    memset(&theader, 0, sizeof(theader));
    theader.epoch = htonl(999);
    theader.cid = 0;
    theader.callNumber = 0;
    theader.seq = 0;
    theader.serial = 0;
    theader.type = RX_PACKET_TYPE_VERSION;
    theader.flags = RX_LAST_PACKET;
    theader.serviceId = 0;

    memcpy(tbuffer, &theader, sizeof(theader));
    memcpy(tp, &a, sizeof(a));
    tmpiov[0].iov_base = tbuffer;
    tmpiov[0].iov_len = 1 + sizeof(struct rx_header);

    osi_NetSend(socket, &taddr, tmpiov, 1, 1 + sizeof(struct rx_header), 1);

    MUTEX_ENTER(&conn->conn_data_lock);
    /* Only reschedule ourselves if the connection would not be destroyed */
    if (conn->refCount <= 1) {
        conn->natKeepAliveEvent = NULL;
        MUTEX_EXIT(&conn->conn_data_lock);
        rx_DestroyConnection(conn); /* drop the reference for this */
    } else {
        conn->natKeepAliveEvent = NULL;
        conn->refCount--; /* drop the reference for this */
        rxi_ScheduleNatKeepAliveEvent(conn);
        MUTEX_EXIT(&conn->conn_data_lock);
    }
}

void
rxi_ScheduleNatKeepAliveEvent(struct rx_connection *conn)
{
    if (!conn->natKeepAliveEvent && conn->secondsUntilNatPing) {
        struct clock when, now;
        clock_GetTime(&now);
        when = now;
        when.sec += conn->secondsUntilNatPing;
        conn->refCount++; /* hold a reference for this */
        conn->natKeepAliveEvent =
            rxevent_PostNow(&when, &now, rxi_NatKeepAliveEvent, conn, 0);
    }
}

void
rx_SetConnSecondsUntilNatPing(struct rx_connection *conn, afs_int32 seconds)
{
    MUTEX_ENTER(&conn->conn_data_lock);
    conn->secondsUntilNatPing = seconds;
    if (seconds != 0)
        rxi_ScheduleNatKeepAliveEvent(conn);
    MUTEX_EXIT(&conn->conn_data_lock);
}

void
rxi_NatKeepAliveOn(struct rx_connection *conn)
{
    MUTEX_ENTER(&conn->conn_data_lock);
    rxi_ScheduleNatKeepAliveEvent(conn);
    MUTEX_EXIT(&conn->conn_data_lock);
}

/* When a call is in progress, this routine is called occasionally to
 * make sure that some traffic has arrived (or been sent to) the peer.
 * If nothing has arrived in a reasonable amount of time, the call is
 * declared dead; if nothing has been sent for a while, we send a
 * keep-alive packet (if we're actually trying to keep the call alive)
 */
void
rxi_KeepAliveEvent(struct rxevent *event, void *arg1, void *dummy)
{
    struct rx_call *call = arg1;
    struct rx_connection *conn;
    afs_uint32 now;

    MUTEX_ENTER(&call->lock);
    CALL_RELE(call, RX_CALL_REFCOUNT_ALIVE);
    if (event == call->keepAliveEvent)
        call->keepAliveEvent = NULL;
    now = clock_Sec();

#ifdef RX_ENABLE_LOCKS
    if (rxi_CheckCall(call, 0)) {
        MUTEX_EXIT(&call->lock);
        return;
    }
#else /* RX_ENABLE_LOCKS */
    if (rxi_CheckCall(call))
        return;
#endif /* RX_ENABLE_LOCKS */

    /* Don't try to keep alive dallying calls */
    if (call->state == RX_STATE_DALLY) {
        MUTEX_EXIT(&call->lock);
        return;
    }

    conn = call->conn;
    if ((now - call->lastSendTime) > conn->secondsUntilPing) {
        /* Don't try to send keepalives if there is unacknowledged data */
        /* the rexmit code should be good enough, this little hack 
         * doesn't quite work XXX */
        (void)rxi_SendAck(call, NULL, 0, RX_ACK_PING, 0);
    }
    rxi_ScheduleKeepAliveEvent(call);
    MUTEX_EXIT(&call->lock);
}


void
rxi_ScheduleKeepAliveEvent(struct rx_call *call)
{
    if (!call->keepAliveEvent) {
        struct clock when, now;
        clock_GetTime(&now);
        when = now;
        when.sec += call->conn->secondsUntilPing;
        CALL_HOLD(call, RX_CALL_REFCOUNT_ALIVE);
        call->keepAliveEvent =
            rxevent_PostNow(&when, &now, rxi_KeepAliveEvent, call, 0);
    }
}

/* N.B. rxi_KeepAliveOff:  is defined earlier as a macro */
void
rxi_KeepAliveOn(struct rx_call *call)
{
    /* Pretend last packet received was received now--i.e. if another
     * packet isn't received within the keep alive time, then the call
     * will die; Initialize last send time to the current time--even
     * if a packet hasn't been sent yet.  This will guarantee that a
     * keep-alive is sent within the ping time */
    call->lastReceiveTime = call->lastSendTime = clock_Sec();
    rxi_ScheduleKeepAliveEvent(call);
}

/* This routine is called to send connection abort messages
 * that have been delayed to throttle looping clients. */
void
rxi_SendDelayedConnAbort(struct rxevent *event,
                         void *arg1, void *unused)
{
    struct rx_connection *conn = arg1;
    
    afs_int32 error;
    struct rx_packet *packet;

    MUTEX_ENTER(&conn->conn_data_lock);
    conn->delayedAbortEvent = NULL;
    error = htonl(conn->error);
    conn->abortCount++;
    MUTEX_EXIT(&conn->conn_data_lock);
    packet = rxi_AllocPacket(RX_PACKET_CLASS_SPECIAL);
    if (packet) {
        packet =
            rxi_SendSpecial((struct rx_call *)0, conn, packet,
                            RX_PACKET_TYPE_ABORT, (char *)&error,
                            sizeof(error), 0);
        rxi_FreePacket(packet);
    }
}

/* This routine is called to send call abort messages
 * that have been delayed to throttle looping clients. */
void
rxi_SendDelayedCallAbort(struct rxevent *event, 
                         void *arg1, void *dummy)
{
    struct rx_call *call = arg1;
    
    afs_int32 error;
    struct rx_packet *packet;

    MUTEX_ENTER(&call->lock);
    call->delayedAbortEvent = NULL;
    error = htonl(call->error);
    call->abortCount++;
    packet = rxi_AllocPacket(RX_PACKET_CLASS_SPECIAL);
    if (packet) {
        packet =
            rxi_SendSpecial(call, call->conn, packet, RX_PACKET_TYPE_ABORT,
                            (char *)&error, sizeof(error), 0);
        rxi_FreePacket(packet);
    }
    CALL_RELE(call, RX_CALL_REFCOUNT_ABORT);
    MUTEX_EXIT(&call->lock);
}

/* This routine is called periodically (every RX_AUTH_REQUEST_TIMEOUT
 * seconds) to ask the client to authenticate itself.  The routine
 * issues a challenge to the client, which is obtained from the
 * security object associated with the connection */
void
rxi_ChallengeEvent(struct rxevent *event, 
                   void *arg0, void *arg1, int tries)
{
    struct rx_connection *conn = arg0;
    
    conn->challengeEvent = NULL;
    if (RXS_CheckAuthentication(conn->securityObject, conn) != 0) {
        struct rx_packet *packet;
        struct clock when, now;

        if (tries <= 0) {
            /* We've failed to authenticate for too long.
             * Reset any calls waiting for authentication;
             * they are all in RX_STATE_PRECALL.
             */
            int i;

            MUTEX_ENTER(&conn->conn_call_lock);
            for (i = 0; i < RX_MAXCALLS; i++) {
                struct rx_call *call = conn->call[i];
                if (call) {
                    MUTEX_ENTER(&call->lock);
                    if (call->state == RX_STATE_PRECALL) {
                        rxi_CallError(call, RX_CALL_DEAD);
                        rxi_SendCallAbort(call, NULL, 0, 0);
                    }
                    MUTEX_EXIT(&call->lock);
                }
            }
            MUTEX_EXIT(&conn->conn_call_lock);
            return;
        }

        packet = rxi_AllocPacket(RX_PACKET_CLASS_SPECIAL);
        if (packet) {
            /* If there's no packet available, do this later. */
            RXS_GetChallenge(conn->securityObject, conn, packet);
            rxi_SendSpecial((struct rx_call *)0, conn, packet,
                            RX_PACKET_TYPE_CHALLENGE, NULL, -1, 0);
            rxi_FreePacket(packet);
        }
        clock_GetTime(&now);
        when = now;
        when.sec += RX_CHALLENGE_TIMEOUT;
        conn->challengeEvent =
            rxevent_PostNow2(&when, &now, rxi_ChallengeEvent, conn, 0,
                         (tries - 1));
    }
}

/* Call this routine to start requesting the client to authenticate
 * itself.  This will continue until authentication is established,
 * the call times out, or an invalid response is returned.  The
 * security object associated with the connection is asked to create
 * the challenge at this time.  N.B.  rxi_ChallengeOff is a macro,
 * defined earlier. */
void
rxi_ChallengeOn(struct rx_connection *conn)
{
    if (!conn->challengeEvent) {
        RXS_CreateChallenge(conn->securityObject, conn);
        rxi_ChallengeEvent(NULL, conn, 0, RX_CHALLENGE_MAXTRIES);
    };
}


/* Compute round trip time of the packet provided, in *rttp.
 */

/* rxi_ComputeRoundTripTime is called with peer locked. */
/* sentp and/or peer may be null */
void
rxi_ComputeRoundTripTime(struct rx_packet *p,
                         struct clock *sentp,
                         struct rx_peer *peer)
{
    struct clock thisRtt, *rttp = &thisRtt;

    int rtt_timeout;

    clock_GetTime(rttp);

    if (clock_Lt(rttp, sentp)) {
        clock_Zero(rttp);
        return;                 /* somebody set the clock back, don't count this time. */
    }
    clock_Sub(rttp, sentp);
    dpf(("rxi_ComputeRoundTripTime(call=%d packet=%"AFS_PTR_FMT" rttp=%d.%06d sec)\n",
          p->header.callNumber, p, rttp->sec, rttp->usec));

    if (rttp->sec == 0 && rttp->usec == 0) {
        /*
         * The actual round trip time is shorter than the
         * clock_GetTime resolution.  It is most likely 1ms or 100ns.
         * Since we can't tell which at the moment we will assume 1ms.
         */
        rttp->usec = 1000;
    }

    if (rx_stats_active) {
        MUTEX_ENTER(&rx_stats_mutex);
        if (clock_Lt(rttp, &rx_stats.minRtt))
            rx_stats.minRtt = *rttp;
        if (clock_Gt(rttp, &rx_stats.maxRtt)) {
            if (rttp->sec > 60) {
                MUTEX_EXIT(&rx_stats_mutex);
                return;         /* somebody set the clock ahead */
            }
            rx_stats.maxRtt = *rttp;
        }
        clock_Add(&rx_stats.totalRtt, rttp);
        rx_stats.nRttSamples++;
        MUTEX_EXIT(&rx_stats_mutex);
    }

    /* better rtt calculation courtesy of UMich crew (dave,larry,peter,?) */

    /* Apply VanJacobson round-trip estimations */
    if (peer->rtt) {
        int delta;

        /*
         * srtt (peer->rtt) is in units of one-eighth-milliseconds.
         * srtt is stored as fixed point with 3 bits after the binary
         * point (i.e., scaled by 8). The following magic is
         * equivalent to the smoothing algorithm in rfc793 with an
         * alpha of .875 (srtt' = rtt/8 + srtt*7/8 in fixed point).
         * srtt'*8 = rtt + srtt*7
         * srtt'*8 = srtt*8 + rtt - srtt
         * srtt' = srtt + rtt/8 - srtt/8
         * srtt' = srtt + (rtt - srtt)/8
         */

        delta = _8THMSEC(rttp) - peer->rtt;
        peer->rtt += (delta >> 3);

        /*
         * We accumulate a smoothed rtt variance (actually, a smoothed
         * mean difference), then set the retransmit timer to smoothed
         * rtt + 4 times the smoothed variance (was 2x in van's original
         * paper, but 4x works better for me, and apparently for him as
         * well).
         * rttvar is stored as
         * fixed point with 2 bits after the binary point (scaled by
         * 4).  The following is equivalent to rfc793 smoothing with
         * an alpha of .75 (rttvar' = rttvar*3/4 + |delta| / 4).
         *   rttvar'*4 = rttvar*3 + |delta|
         *   rttvar'*4 = rttvar*4 + |delta| - rttvar
         *   rttvar' = rttvar + |delta|/4 - rttvar/4
         *   rttvar' = rttvar + (|delta| - rttvar)/4
         * This replaces rfc793's wired-in beta.
         * dev*4 = dev*4 + (|actual - expected| - dev)
         */

        if (delta < 0)
            delta = -delta;

        delta -= (peer->rtt_dev << 1);
        peer->rtt_dev += (delta >> 3);
    } else {
        /* I don't have a stored RTT so I start with this value.  Since I'm
         * probably just starting a call, and will be pushing more data down
         * this, I expect congestion to increase rapidly.  So I fudge a 
         * little, and I set deviance to half the rtt.  In practice,
         * deviance tends to approach something a little less than
         * half the smoothed rtt. */
        peer->rtt = _8THMSEC(rttp) + 8;
        peer->rtt_dev = peer->rtt >> 2; /* rtt/2: they're scaled differently */
    }
    /* the timeout is RTT + 4*MDEV but no less than rx_minPeerTimeout msec.
     * This is because one end or the other of these connections is usually
     * in a user process, and can be switched and/or swapped out.  So on fast,
     * reliable networks, the timeout would otherwise be too short. */
    rtt_timeout = MAX(((peer->rtt >> 3) + peer->rtt_dev), rx_minPeerTimeout);
    clock_Zero(&(peer->timeout));
    clock_Addmsec(&(peer->timeout), rtt_timeout);

    dpf(("rxi_ComputeRoundTripTime(call=%d packet=%"AFS_PTR_FMT" rtt=%d ms, srtt=%d ms, rtt_dev=%d ms, timeout=%d.%06d sec)\n",
          p->header.callNumber, p, MSEC(rttp), peer->rtt >> 3, peer->rtt_dev >> 2, (peer->timeout.sec), (peer->timeout.usec)));
}


/* Find all server connections that have not been active for a long time, and
 * toss them */
void
rxi_ReapConnections(struct rxevent *unused, void *unused1, void *unused2)
{
    struct clock now, when;
    clock_GetTime(&now);

    /* Find server connection structures that haven't been used for
     * greater than rx_idleConnectionTime */
    {
        struct rx_connection **conn_ptr, **conn_end;
        int i, havecalls = 0;
        MUTEX_ENTER(&rx_connHashTable_lock);
        for (conn_ptr = &rx_connHashTable[0], conn_end =
             &rx_connHashTable[rx_hashTableSize]; conn_ptr < conn_end;
             conn_ptr++) {
            struct rx_connection *conn, *next;
            struct rx_call *call;
            int result;

          rereap:
            for (conn = *conn_ptr; conn; conn = next) {
                /* XXX -- Shouldn't the connection be locked? */
                next = conn->next;
                havecalls = 0;
                for (i = 0; i < RX_MAXCALLS; i++) {
                    call = conn->call[i];
                    if (call) {
                        int code;
                        havecalls = 1;
                        code = MUTEX_TRYENTER(&call->lock);
                        if (!code)
                            continue;
#ifdef RX_ENABLE_LOCKS
                        result = rxi_CheckCall(call, 1);
#else /* RX_ENABLE_LOCKS */
                        result = rxi_CheckCall(call);
#endif /* RX_ENABLE_LOCKS */
                        MUTEX_EXIT(&call->lock);
                        if (result == -2) {
                            /* If CheckCall freed the call, it might
                             * have destroyed  the connection as well,
                             * which screws up the linked lists.
                             */
                            goto rereap;
                        }
                    }
                }
                if (conn->type == RX_SERVER_CONNECTION) {
                    /* This only actually destroys the connection if
                     * there are no outstanding calls */
                    MUTEX_ENTER(&conn->conn_data_lock);
                    if (!havecalls && !conn->refCount
                        && ((conn->lastSendTime + rx_idleConnectionTime) <
                            now.sec)) {
                        conn->refCount++;       /* it will be decr in rx_DestroyConn */
                        MUTEX_EXIT(&conn->conn_data_lock);
#ifdef RX_ENABLE_LOCKS
                        rxi_DestroyConnectionNoLock(conn);
#else /* RX_ENABLE_LOCKS */
                        rxi_DestroyConnection(conn);
#endif /* RX_ENABLE_LOCKS */
                    }
#ifdef RX_ENABLE_LOCKS
                    else {
                        MUTEX_EXIT(&conn->conn_data_lock);
                    }
#endif /* RX_ENABLE_LOCKS */
                }
            }
        }
#ifdef RX_ENABLE_LOCKS
        while (rx_connCleanup_list) {
            struct rx_connection *conn;
            conn = rx_connCleanup_list;
            rx_connCleanup_list = rx_connCleanup_list->next;
            MUTEX_EXIT(&rx_connHashTable_lock);
            rxi_CleanupConnection(conn);
            MUTEX_ENTER(&rx_connHashTable_lock);
        }
        MUTEX_EXIT(&rx_connHashTable_lock);
#endif /* RX_ENABLE_LOCKS */
    }

    /* Find any peer structures that haven't been used (haven't had an
     * associated connection) for greater than rx_idlePeerTime */
    {
        struct rx_peer **peer_ptr, **peer_end;
        int code;
        MUTEX_ENTER(&rx_rpc_stats);
        MUTEX_ENTER(&rx_peerHashTable_lock);
        for (peer_ptr = &rx_peerHashTable[0], peer_end =
             &rx_peerHashTable[rx_hashTableSize]; peer_ptr < peer_end;
             peer_ptr++) {
            struct rx_peer *peer, *next, *prev;
            for (prev = peer = *peer_ptr; peer; peer = next) {
                next = peer->next;
                code = MUTEX_TRYENTER(&peer->peer_lock);
                if ((code) && (peer->refCount == 0)
                    && ((peer->idleWhen + rx_idlePeerTime) < now.sec)) {
                    rx_interface_stat_p rpc_stat, nrpc_stat;
                    size_t space;
                    MUTEX_EXIT(&peer->peer_lock);
                    MUTEX_DESTROY(&peer->peer_lock);
                    for (queue_Scan
                         (&peer->rpcStats, rpc_stat, nrpc_stat,
                          rx_interface_stat)) {
                        unsigned int num_funcs;
                        if (!rpc_stat)
                            break;
                        queue_Remove(&rpc_stat->queue_header);
                        queue_Remove(&rpc_stat->all_peers);
                        num_funcs = rpc_stat->stats[0].func_total;
                        space =
                            sizeof(rx_interface_stat_t) +
                            rpc_stat->stats[0].func_total *
                            sizeof(rx_function_entry_v1_t);

                        rxi_Free(rpc_stat, space);
                        rxi_rpc_peer_stat_cnt -= num_funcs;
                    }
                    rxi_FreePeer(peer);
                    if (rx_stats_active)
                        rx_MutexDecrement(rx_stats.nPeerStructs, rx_stats_mutex);
                    if (peer == *peer_ptr) {
                        *peer_ptr = next;
                        prev = next;
                    } else
                        prev->next = next;
                } else {
                    if (code) {
                        MUTEX_EXIT(&peer->peer_lock);
                    }
                    prev = peer;
                }
            }
        }
        MUTEX_EXIT(&rx_peerHashTable_lock);
        MUTEX_EXIT(&rx_rpc_stats);
    }

    /* THIS HACK IS A TEMPORARY HACK.  The idea is that the race condition in
     * rxi_AllocSendPacket, if it hits, will be handled at the next conn
     * GC, just below.  Really, we shouldn't have to keep moving packets from
     * one place to another, but instead ought to always know if we can
     * afford to hold onto a packet in its particular use.  */
    MUTEX_ENTER(&rx_freePktQ_lock);
    if (rx_waitingForPackets) {
        rx_waitingForPackets = 0;
#ifdef  RX_ENABLE_LOCKS
        CV_BROADCAST(&rx_waitingForPackets_cv);
#else
        osi_rxWakeup(&rx_waitingForPackets);
#endif
    }
    MUTEX_EXIT(&rx_freePktQ_lock);

    when = now;
    when.sec += RX_REAP_TIME;   /* Check every RX_REAP_TIME seconds */
    rxevent_Post(&when, rxi_ReapConnections, 0, 0);
}


/* rxs_Release - This isn't strictly necessary but, since the macro name from
 * rx.h is sort of strange this is better.  This is called with a security
 * object before it is discarded.  Each connection using a security object has
 * its own refcount to the object so it won't actually be freed until the last
 * connection is destroyed.
 *
 * This is the only rxs module call.  A hold could also be written but no one
 * needs it. */

int
rxs_Release(struct rx_securityClass *aobj)
{
    return RXS_Close(aobj);
}

#ifdef ADAPT_WINDOW
#define RXRATE_PKT_OH   (RX_HEADER_SIZE + RX_IPUDP_SIZE)
#define RXRATE_SMALL_PKT    (RXRATE_PKT_OH + sizeof(struct rx_ackPacket))
#define RXRATE_AVG_SMALL_PKT    (RXRATE_PKT_OH + (sizeof(struct rx_ackPacket)/2))
#define RXRATE_LARGE_PKT    (RXRATE_SMALL_PKT + 256)

/* Adjust our estimate of the transmission rate to this peer, given
 * that the packet p was just acked. We can adjust peer->timeout and
 * call->twind. Pragmatically, this is called
 * only with packets of maximal length.
 * Called with peer and call locked.
 */

static void
rxi_ComputeRate(struct rx_peer *peer, struct rx_call *call,
                struct rx_packet *p, struct rx_packet *ackp, u_char ackReason)
{
    afs_int32 xferSize, xferMs;
    afs_int32 minTime;
    struct clock newTO;

    /* Count down packets */
    if (peer->rateFlag > 0)
        peer->rateFlag--;
    /* Do nothing until we're enabled */
    if (peer->rateFlag != 0)
        return;
    if (!call->conn)
        return;

    /* Count only when the ack seems legitimate */
    switch (ackReason) {
    case RX_ACK_REQUESTED:
        xferSize =
            p->length + RX_HEADER_SIZE + call->conn->securityMaxTrailerSize;
        xferMs = peer->rtt;
        break;

    case RX_ACK_PING_RESPONSE:
        if (p)                  /* want the response to ping-request, not data send */
            return;
        clock_GetTime(&newTO);
        if (clock_Gt(&newTO, &call->pingRequestTime)) {
            clock_Sub(&newTO, &call->pingRequestTime);
            xferMs = (newTO.sec * 1000) + (newTO.usec / 1000);
        } else {
            return;
        }
        xferSize = rx_AckDataSize(rx_Window) + RX_HEADER_SIZE;
        break;

    default:
        return;
    }

    dpf(("CONG peer %lx/%u: sample (%s) size %ld, %ld ms (to %d.%06d, rtt %u, ps %u)",
          ntohl(peer->host), ntohs(peer->port), (ackReason == RX_ACK_REQUESTED ? "dataack" : "pingack"),
          xferSize, xferMs, peer->timeout.sec, peer->timeout.usec, peer->smRtt, peer->ifMTU));

    /* Track only packets that are big enough. */
    if ((p->length + RX_HEADER_SIZE + call->conn->securityMaxTrailerSize) <
        peer->ifMTU)
        return;

    /* absorb RTT data (in milliseconds) for these big packets */
    if (peer->smRtt == 0) {
        peer->smRtt = xferMs;
    } else {
        peer->smRtt = ((peer->smRtt * 15) + xferMs + 4) >> 4;
        if (!peer->smRtt)
            peer->smRtt = 1;
    }

    if (peer->countDown) {
        peer->countDown--;
        return;
    }
    peer->countDown = 10;       /* recalculate only every so often */

    /* In practice, we can measure only the RTT for full packets,
     * because of the way Rx acks the data that it receives.  (If it's
     * smaller than a full packet, it often gets implicitly acked
     * either by the call response (from a server) or by the next call
     * (from a client), and either case confuses transmission times
     * with processing times.)  Therefore, replace the above
     * more-sophisticated processing with a simpler version, where the
     * smoothed RTT is kept for full-size packets, and the time to
     * transmit a windowful of full-size packets is simply RTT *
     * windowSize. Again, we take two steps:
     - ensure the timeout is large enough for a single packet's RTT;
     - ensure that the window is small enough to fit in the desired timeout.*/

    /* First, the timeout check. */
    minTime = peer->smRtt;
    /* Get a reasonable estimate for a timeout period */
    minTime += minTime;
    newTO.sec = minTime / 1000;
    newTO.usec = (minTime - (newTO.sec * 1000)) * 1000;

    /* Increase the timeout period so that we can always do at least
     * one packet exchange */
    if (clock_Gt(&newTO, &peer->timeout)) {

        dpf(("CONG peer %lx/%u: timeout %d.%06d ==> %ld.%06d (rtt %u, ps %u)",
              ntohl(peer->host), ntohs(peer->port), peer->timeout.sec, peer->timeout.usec,
              newTO.sec, newTO.usec, peer->smRtt, peer->packetSize));

        peer->timeout = newTO;
    }

    /* Now, get an estimate for the transmit window size. */
    minTime = peer->timeout.sec * 1000 + (peer->timeout.usec / 1000);
    /* Now, convert to the number of full packets that could fit in a
     * reasonable fraction of that interval */
    minTime /= (peer->smRtt << 1);
    xferSize = minTime;         /* (make a copy) */

    /* Now clamp the size to reasonable bounds. */
    if (minTime <= 1)
        minTime = 1;
    else if (minTime > rx_Window)
        minTime = rx_Window;
/*    if (minTime != peer->maxWindow) {
      dpf(("CONG peer %lx/%u: windowsize %lu ==> %lu (to %lu.%06lu, rtt %u, ps %u)",
             ntohl(peer->host), ntohs(peer->port), peer->maxWindow, minTime,
             peer->timeout.sec, peer->timeout.usec, peer->smRtt,
             peer->packetSize));
      peer->maxWindow = minTime;
        elide... call->twind = minTime; 
    }
*/

    /* Cut back on the peer timeout if it had earlier grown unreasonably.
     * Discern this by calculating the timeout necessary for rx_Window
     * packets. */
    if ((xferSize > rx_Window) && (peer->timeout.sec >= 3)) {
        /* calculate estimate for transmission interval in milliseconds */
        minTime = rx_Window * peer->smRtt;
        if (minTime < 1000) {
            dpf(("CONG peer %lx/%u: cut TO %d.%06d by 0.5 (rtt %u, ps %u)",
                 ntohl(peer->host), ntohs(peer->port), peer->timeout.sec,
                 peer->timeout.usec, peer->smRtt, peer->packetSize));

            newTO.sec = 0;      /* cut back on timeout by half a second */
            newTO.usec = 500000;
            clock_Sub(&peer->timeout, &newTO);
        }
    }

    return;
}                               /* end of rxi_ComputeRate */
#endif /* ADAPT_WINDOW */


void
rxi_DebugInit(void)
{
#ifdef RXDEBUG
#ifdef AFS_NT40_ENV
#define TRACE_OPTION_RX_DEBUG 16
    HKEY parmKey;
    DWORD dummyLen;
    DWORD TraceOption;
    long code;

    rxdebug_active = 0;

    code = RegOpenKeyEx(HKEY_LOCAL_MACHINE, AFSREG_CLT_SVC_PARAM_SUBKEY,
                         0, KEY_QUERY_VALUE, &parmKey);
    if (code != ERROR_SUCCESS)
        return;

    dummyLen = sizeof(TraceOption);
    code = RegQueryValueEx(parmKey, "TraceOption", NULL, NULL,
                           (BYTE *) &TraceOption, &dummyLen);
    if (code == ERROR_SUCCESS) {
        rxdebug_active = (TraceOption & TRACE_OPTION_RX_DEBUG) ? 1 : 0;
    }
    RegCloseKey (parmKey);
#endif /* AFS_NT40_ENV */
#endif
}

void
rx_DebugOnOff(int on)
{
#ifdef RXDEBUG
#ifdef AFS_NT40_ENV
    rxdebug_active = on;
#endif
#endif
}

void
rx_StatsOnOff(int on)
{
#ifdef RXDEBUG
    rx_stats_active = on;
#endif
}


/* Don't call this debugging routine directly; use dpf */
void
rxi_DebugPrint(char *format, ...)
{
#ifdef RXDEBUG
    va_list ap;
#ifdef AFS_NT40_ENV
    char msg[512];
    char tformat[256];
    size_t len;

    va_start(ap, format);

    len = _snprintf(tformat, sizeof(tformat), "tid[%d] %s", GetCurrentThreadId(), format);

    if (len > 0) {
        len = _vsnprintf(msg, sizeof(msg)-2, tformat, ap);
        if (len > 0) {
            if (msg[len-1] != '\n') {
                msg[len] = '\n';
                msg[len+1] = '\0';
            }
            OutputDebugString(msg);
        }
    }
    va_end(ap);
#else
    struct clock now;
    
    va_start(ap, format);

    clock_GetTime(&now);
    fprintf(rx_Log, " %d.%06d:", (unsigned int)now.sec,
            (unsigned int)now.usec);
    vfprintf(rx_Log, format, ap);
    putc('\n', rx_Log);
    va_end(ap);
#endif
#endif
}

#ifndef KERNEL
/*
 * This function is used to process the rx_stats structure that is local
 * to a process as well as an rx_stats structure received from a remote
 * process (via rxdebug).  Therefore, it needs to do minimal version
 * checking.
 */
void
rx_PrintTheseStats(FILE * file, struct rx_statistics *s, int size,
                   afs_int32 freePackets, char version)
{
#ifdef RXDEBUG
    int i;

    if (size != sizeof(struct rx_statistics)) {
        fprintf(file,
                "Unexpected size of stats structure: was %d, expected %" AFS_SIZET_FMT "\n",
                size, sizeof(struct rx_statistics));
    }

    fprintf(file, "rx stats: free packets %d, allocs %d, ", (int)freePackets,
            s->packetRequests);

    if (version >= RX_DEBUGI_VERSION_W_NEWPACKETTYPES) {
        fprintf(file, "alloc-failures(rcv %u/%u,send %u/%u,ack %u)\n",
                s->receivePktAllocFailures, s->receiveCbufPktAllocFailures,
                s->sendPktAllocFailures, s->sendCbufPktAllocFailures,
                s->specialPktAllocFailures);
    } else {
        fprintf(file, "alloc-failures(rcv %u,send %u,ack %u)\n",
                s->receivePktAllocFailures, s->sendPktAllocFailures,
                s->specialPktAllocFailures);
    }

    fprintf(file,
            "   greedy %u, " "bogusReads %u (last from host %x), "
            "noPackets %u, " "noBuffers %u, " "selects %u, "
            "sendSelects %u\n", s->socketGreedy, s->bogusPacketOnRead,
            s->bogusHost, s->noPacketOnRead, s->noPacketBuffersOnRead,
            s->selects, s->sendSelects);

    fprintf(file, "   packets read: ");
    for (i = 0; i < RX_N_PACKET_TYPES; i++) {
        fprintf(file, "%s %u ", rx_packetTypes[i], s->packetsRead[i]);
    }
    fprintf(file, "\n");

    fprintf(file,
            "   other read counters: data %u, " "ack %u, " "dup %u "
            "spurious %u " "dally %u\n", s->dataPacketsRead,
            s->ackPacketsRead, s->dupPacketsRead, s->spuriousPacketsRead,
            s->ignorePacketDally);

    fprintf(file, "   packets sent: ");
    for (i = 0; i < RX_N_PACKET_TYPES; i++) {
        fprintf(file, "%s %u ", rx_packetTypes[i], s->packetsSent[i]);
    }
    fprintf(file, "\n");

    fprintf(file,
            "   other send counters: ack %u, " "data %u (not resends), "
            "resends %u, " "pushed %u, " "acked&ignored %u\n",
            s->ackPacketsSent, s->dataPacketsSent, s->dataPacketsReSent,
            s->dataPacketsPushed, s->ignoreAckedPacket);

    fprintf(file,
            "   \t(these should be small) sendFailed %u, " "fatalErrors %u\n",
            s->netSendFailures, (int)s->fatalErrors);

    if (s->nRttSamples) {
        fprintf(file, "   Average rtt is %0.3f, with %d samples\n",
                clock_Float(&s->totalRtt) / s->nRttSamples, s->nRttSamples);

        fprintf(file, "   Minimum rtt is %0.3f, maximum is %0.3f\n",
                clock_Float(&s->minRtt), clock_Float(&s->maxRtt));
    }

    fprintf(file,
            "   %d server connections, " "%d client connections, "
            "%d peer structs, " "%d call structs, " "%d free call structs\n",
            s->nServerConns, s->nClientConns, s->nPeerStructs,
            s->nCallStructs, s->nFreeCallStructs);

#if     !defined(AFS_PTHREAD_ENV) && !defined(AFS_USE_GETTIMEOFDAY)
    fprintf(file, "   %d clock updates\n", clock_nUpdates);
#endif
#else
    fprintf(file, "ERROR: compiled without RXDEBUG\n");
#endif
}

/* for backward compatibility */
void
rx_PrintStats(FILE * file)
{
    MUTEX_ENTER(&rx_stats_mutex);
    rx_PrintTheseStats(file, &rx_stats, sizeof(rx_stats), rx_nFreePackets,
                       RX_DEBUGI_VERSION);
    MUTEX_EXIT(&rx_stats_mutex);
}

void
rx_PrintPeerStats(FILE * file, struct rx_peer *peer)
{
    fprintf(file, "Peer %x.%d.  " "Burst size %d, " "burst wait %d.%06d.\n",
            ntohl(peer->host), (int)peer->port, (int)peer->burstSize,
            (int)peer->burstWait.sec, (int)peer->burstWait.usec);

    fprintf(file,
            "   Rtt %d, " "retry time %u.%06d, " "total sent %d, "
            "resent %d\n", peer->rtt, (int)peer->timeout.sec,
            (int)peer->timeout.usec, peer->nSent, peer->reSends);

    fprintf(file,
            "   Packet size %d, " "max in packet skew %d, "
            "max out packet skew %d\n", peer->ifMTU, (int)peer->inPacketSkew,
            (int)peer->outPacketSkew);
}
#endif

#if defined(AFS_PTHREAD_ENV) && defined(RXDEBUG)
/*
 * This mutex protects the following static variables:
 * counter
 */

#define LOCK_RX_DEBUG MUTEX_ENTER(&rx_debug_mutex)
#define UNLOCK_RX_DEBUG MUTEX_EXIT(&rx_debug_mutex)
#else
#define LOCK_RX_DEBUG
#define UNLOCK_RX_DEBUG
#endif /* AFS_PTHREAD_ENV */

#ifdef RXDEBUG
static int
MakeDebugCall(osi_socket socket, afs_uint32 remoteAddr, afs_uint16 remotePort,
              u_char type, void *inputData, size_t inputLength,
              void *outputData, size_t outputLength)
{
    static afs_int32 counter = 100;
    time_t waitTime, waitCount, startTime;
    struct rx_header theader;
    char tbuffer[1500];
    afs_int32 code;
    struct timeval tv_now, tv_wake, tv_delta;
    struct sockaddr_in taddr, faddr;
#ifdef AFS_NT40_ENV
    int faddrLen;
#else
    socklen_t faddrLen;
#endif
    fd_set imask;
    char *tp;

    startTime = time(0);
    waitTime = 1;
    waitCount = 5;
    LOCK_RX_DEBUG;
    counter++;
    UNLOCK_RX_DEBUG;
    tp = &tbuffer[sizeof(struct rx_header)];
    taddr.sin_family = AF_INET;
    taddr.sin_port = remotePort;
    taddr.sin_addr.s_addr = remoteAddr;
#ifdef STRUCT_SOCKADDR_HAS_SA_LEN
    taddr.sin_len = sizeof(struct sockaddr_in);
#endif
    while (1) {
        memset(&theader, 0, sizeof(theader));
        theader.epoch = htonl(999);
        theader.cid = 0;
        theader.callNumber = htonl(counter);
        theader.seq = 0;
        theader.serial = 0;
        theader.type = type;
        theader.flags = RX_CLIENT_INITIATED | RX_LAST_PACKET;
        theader.serviceId = 0;

        memcpy(tbuffer, &theader, sizeof(theader));
        memcpy(tp, inputData, inputLength);
        code =
            sendto(socket, tbuffer, inputLength + sizeof(struct rx_header), 0,
                   (struct sockaddr *)&taddr, sizeof(struct sockaddr_in));

        /* see if there's a packet available */
        gettimeofday(&tv_wake,0);
        tv_wake.tv_sec += waitTime;
        for (;;) {
            FD_ZERO(&imask);
            FD_SET(socket, &imask);
            tv_delta.tv_sec = tv_wake.tv_sec;
            tv_delta.tv_usec = tv_wake.tv_usec;
            gettimeofday(&tv_now, 0);
            
            if (tv_delta.tv_usec < tv_now.tv_usec) {
                /* borrow */
                tv_delta.tv_usec += 1000000;
                tv_delta.tv_sec--;
            }
            tv_delta.tv_usec -= tv_now.tv_usec;
            
            if (tv_delta.tv_sec < tv_now.tv_sec) {
                /* time expired */
                break;
            }
            tv_delta.tv_sec -= tv_now.tv_sec;
            
#ifdef AFS_NT40_ENV
            code = select(0, &imask, 0, 0, &tv_delta);
#else /* AFS_NT40_ENV */
            code = select(socket + 1, &imask, 0, 0, &tv_delta);
#endif /* AFS_NT40_ENV */
            if (code == 1 && FD_ISSET(socket, &imask)) {
                /* now receive a packet */
                faddrLen = sizeof(struct sockaddr_in);
                code =
                    recvfrom(socket, tbuffer, sizeof(tbuffer), 0,
                             (struct sockaddr *)&faddr, &faddrLen);
                
                if (code > 0) {
                    memcpy(&theader, tbuffer, sizeof(struct rx_header));
                    if (counter == ntohl(theader.callNumber))
                        goto success;
                    continue;
                }
            }
            break;
        }

        /* see if we've timed out */
        if (!--waitCount) {
            return -1;
        }
        waitTime <<= 1;
    }
    
 success:
    code -= sizeof(struct rx_header);
    if (code > outputLength)
        code = outputLength;
    memcpy(outputData, tp, code);
    return code;
}
#endif /* RXDEBUG */

afs_int32
rx_GetServerDebug(osi_socket socket, afs_uint32 remoteAddr,
                  afs_uint16 remotePort, struct rx_debugStats * stat,
                  afs_uint32 * supportedValues)
{
#ifndef RXDEBUG
     afs_int32 rc = -1;
#else
    afs_int32 rc = 0;
    struct rx_debugIn in;

    *supportedValues = 0;
    in.type = htonl(RX_DEBUGI_GETSTATS);
    in.index = 0;

    rc = MakeDebugCall(socket, remoteAddr, remotePort, RX_PACKET_TYPE_DEBUG,
                       &in, sizeof(in), stat, sizeof(*stat));

    /*
     * If the call was successful, fixup the version and indicate
     * what contents of the stat structure are valid.
     * Also do net to host conversion of fields here.
     */

    if (rc >= 0) {
        if (stat->version >= RX_DEBUGI_VERSION_W_SECSTATS) {
            *supportedValues |= RX_SERVER_DEBUG_SEC_STATS;
        }
        if (stat->version >= RX_DEBUGI_VERSION_W_GETALLCONN) {
            *supportedValues |= RX_SERVER_DEBUG_ALL_CONN;
        }
        if (stat->version >= RX_DEBUGI_VERSION_W_RXSTATS) {
            *supportedValues |= RX_SERVER_DEBUG_RX_STATS;
        }
        if (stat->version >= RX_DEBUGI_VERSION_W_WAITERS) {
            *supportedValues |= RX_SERVER_DEBUG_WAITER_CNT;
        }
        if (stat->version >= RX_DEBUGI_VERSION_W_IDLETHREADS) {
            *supportedValues |= RX_SERVER_DEBUG_IDLE_THREADS;
        }
        if (stat->version >= RX_DEBUGI_VERSION_W_NEWPACKETTYPES) {
            *supportedValues |= RX_SERVER_DEBUG_NEW_PACKETS;
        }
        if (stat->version >= RX_DEBUGI_VERSION_W_GETPEER) {
            *supportedValues |= RX_SERVER_DEBUG_ALL_PEER;
        }
        if (stat->version >= RX_DEBUGI_VERSION_W_WAITED) {
            *supportedValues |= RX_SERVER_DEBUG_WAITED_CNT;
        }
        if (stat->version >= RX_DEBUGI_VERSION_W_PACKETS) {
            *supportedValues |= RX_SERVER_DEBUG_PACKETS_CNT;
        }
        stat->nFreePackets = ntohl(stat->nFreePackets);
        stat->packetReclaims = ntohl(stat->packetReclaims);
        stat->callsExecuted = ntohl(stat->callsExecuted);
        stat->nWaiting = ntohl(stat->nWaiting);
        stat->idleThreads = ntohl(stat->idleThreads);
        stat->nWaited = ntohl(stat->nWaited);
        stat->nPackets = ntohl(stat->nPackets);
    }
#endif
    return rc;
}

afs_int32
rx_GetServerStats(osi_socket socket, afs_uint32 remoteAddr,
                  afs_uint16 remotePort, struct rx_statistics * stat,
                  afs_uint32 * supportedValues)
{
#ifndef RXDEBUG
     afs_int32 rc = -1;
#else
    afs_int32 rc = 0;
    struct rx_debugIn in;
    afs_int32 *lp = (afs_int32 *) stat;
    int i;

    /*
     * supportedValues is currently unused, but added to allow future
     * versioning of this function.
     */

    *supportedValues = 0;
    in.type = htonl(RX_DEBUGI_RXSTATS);
    in.index = 0;
    memset(stat, 0, sizeof(*stat));

    rc = MakeDebugCall(socket, remoteAddr, remotePort, RX_PACKET_TYPE_DEBUG,
                       &in, sizeof(in), stat, sizeof(*stat));

    if (rc >= 0) {

        /*
         * Do net to host conversion here
         */

        for (i = 0; i < sizeof(*stat) / sizeof(afs_int32); i++, lp++) {
            *lp = ntohl(*lp);
        }
    }
#endif
    return rc;
}

afs_int32
rx_GetServerVersion(osi_socket socket, afs_uint32 remoteAddr,
                    afs_uint16 remotePort, size_t version_length,
                    char *version)
{
#ifdef RXDEBUG
    char a[1] = { 0 };
    return MakeDebugCall(socket, remoteAddr, remotePort,
                         RX_PACKET_TYPE_VERSION, a, 1, version,
                         version_length);
#else
    return -1;
#endif
}

afs_int32
rx_GetServerConnections(osi_socket socket, afs_uint32 remoteAddr,
                        afs_uint16 remotePort, afs_int32 * nextConnection,
                        int allConnections, afs_uint32 debugSupportedValues,
                        struct rx_debugConn * conn,
                        afs_uint32 * supportedValues)
{
#ifndef RXDEBUG
    afs_int32 rc = -1;
#else
    afs_int32 rc = 0;
    struct rx_debugIn in;
    int i;

    /*
     * supportedValues is currently unused, but added to allow future
     * versioning of this function.
     */

    *supportedValues = 0;
    if (allConnections) {
        in.type = htonl(RX_DEBUGI_GETALLCONN);
    } else {
        in.type = htonl(RX_DEBUGI_GETCONN);
    }
    in.index = htonl(*nextConnection);
    memset(conn, 0, sizeof(*conn));

    rc = MakeDebugCall(socket, remoteAddr, remotePort, RX_PACKET_TYPE_DEBUG,
                       &in, sizeof(in), conn, sizeof(*conn));

    if (rc >= 0) {
        *nextConnection += 1;

        /*
         * Convert old connection format to new structure.
         */

        if (debugSupportedValues & RX_SERVER_DEBUG_OLD_CONN) {
            struct rx_debugConn_vL *vL = (struct rx_debugConn_vL *)conn;
#define MOVEvL(a) (conn->a = vL->a)

            /* any old or unrecognized version... */
            for (i = 0; i < RX_MAXCALLS; i++) {
                MOVEvL(callState[i]);
                MOVEvL(callMode[i]);
                MOVEvL(callFlags[i]);
                MOVEvL(callOther[i]);
            }
            if (debugSupportedValues & RX_SERVER_DEBUG_SEC_STATS) {
                MOVEvL(secStats.type);
                MOVEvL(secStats.level);
                MOVEvL(secStats.flags);
                MOVEvL(secStats.expires);
                MOVEvL(secStats.packetsReceived);
                MOVEvL(secStats.packetsSent);
                MOVEvL(secStats.bytesReceived);
                MOVEvL(secStats.bytesSent);
            }
        }

        /*
         * Do net to host conversion here
         * NOTE:
         *    I don't convert host or port since we are most likely
         *    going to want these in NBO.
         */
        conn->cid = ntohl(conn->cid);
        conn->serial = ntohl(conn->serial);
        for (i = 0; i < RX_MAXCALLS; i++) {
            conn->callNumber[i] = ntohl(conn->callNumber[i]);
        }
        conn->error = ntohl(conn->error);
        conn->secStats.flags = ntohl(conn->secStats.flags);
        conn->secStats.expires = ntohl(conn->secStats.expires);
        conn->secStats.packetsReceived =
            ntohl(conn->secStats.packetsReceived);
        conn->secStats.packetsSent = ntohl(conn->secStats.packetsSent);
        conn->secStats.bytesReceived = ntohl(conn->secStats.bytesReceived);
        conn->secStats.bytesSent = ntohl(conn->secStats.bytesSent);
        conn->epoch = ntohl(conn->epoch);
        conn->natMTU = ntohl(conn->natMTU);
    }
#endif
    return rc;
}

afs_int32
rx_GetServerPeers(osi_socket socket, afs_uint32 remoteAddr,
                  afs_uint16 remotePort, afs_int32 * nextPeer,
                  afs_uint32 debugSupportedValues, struct rx_debugPeer * peer,
                  afs_uint32 * supportedValues)
{
#ifndef RXDEBUG
    afs_int32 rc = -1;
#else
    afs_int32 rc = 0;
    struct rx_debugIn in;

    /*
     * supportedValues is currently unused, but added to allow future
     * versioning of this function.
     */

    *supportedValues = 0;
    in.type = htonl(RX_DEBUGI_GETPEER);
    in.index = htonl(*nextPeer);
    memset(peer, 0, sizeof(*peer));

    rc = MakeDebugCall(socket, remoteAddr, remotePort, RX_PACKET_TYPE_DEBUG,
                       &in, sizeof(in), peer, sizeof(*peer));

    if (rc >= 0) {
        *nextPeer += 1;

        /*
         * Do net to host conversion here
         * NOTE:
         *    I don't convert host or port since we are most likely
         *    going to want these in NBO.
         */
        peer->ifMTU = ntohs(peer->ifMTU);
        peer->idleWhen = ntohl(peer->idleWhen);
        peer->refCount = ntohs(peer->refCount);
        peer->burstWait.sec = ntohl(peer->burstWait.sec);
        peer->burstWait.usec = ntohl(peer->burstWait.usec);
        peer->rtt = ntohl(peer->rtt);
        peer->rtt_dev = ntohl(peer->rtt_dev);
        peer->timeout.sec = ntohl(peer->timeout.sec);
        peer->timeout.usec = ntohl(peer->timeout.usec);
        peer->nSent = ntohl(peer->nSent);
        peer->reSends = ntohl(peer->reSends);
        peer->inPacketSkew = ntohl(peer->inPacketSkew);
        peer->outPacketSkew = ntohl(peer->outPacketSkew);
        peer->rateFlag = ntohl(peer->rateFlag);
        peer->natMTU = ntohs(peer->natMTU);
        peer->maxMTU = ntohs(peer->maxMTU);
        peer->maxDgramPackets = ntohs(peer->maxDgramPackets);
        peer->ifDgramPackets = ntohs(peer->ifDgramPackets);
        peer->MTU = ntohs(peer->MTU);
        peer->cwind = ntohs(peer->cwind);
        peer->nDgramPackets = ntohs(peer->nDgramPackets);
        peer->congestSeq = ntohs(peer->congestSeq);
        peer->bytesSent.high = ntohl(peer->bytesSent.high);
        peer->bytesSent.low = ntohl(peer->bytesSent.low);
        peer->bytesReceived.high = ntohl(peer->bytesReceived.high);
        peer->bytesReceived.low = ntohl(peer->bytesReceived.low);
    }
#endif
    return rc;
}

afs_int32 
rx_GetLocalPeers(afs_uint32 peerHost, afs_uint16 peerPort,
                struct rx_debugPeer * peerStats)
{
        struct rx_peer *tp;
        afs_int32 error = 1; /* default to "did not succeed" */
        afs_uint32 hashValue = PEER_HASH(peerHost, peerPort);

        MUTEX_ENTER(&rx_peerHashTable_lock);
        for(tp = rx_peerHashTable[hashValue]; 
              tp != NULL; tp = tp->next) {
                if (tp->host == peerHost)
                        break;
        }

        if (tp) {
                error = 0;

                peerStats->host = tp->host;
                peerStats->port = tp->port;
                peerStats->ifMTU = tp->ifMTU;
                peerStats->idleWhen = tp->idleWhen;
                peerStats->refCount = tp->refCount;
                peerStats->burstSize = tp->burstSize;
                peerStats->burst = tp->burst;
                peerStats->burstWait.sec = tp->burstWait.sec;
                peerStats->burstWait.usec = tp->burstWait.usec;
                peerStats->rtt = tp->rtt;
                peerStats->rtt_dev = tp->rtt_dev;
                peerStats->timeout.sec = tp->timeout.sec;
                peerStats->timeout.usec = tp->timeout.usec;
                peerStats->nSent = tp->nSent;
                peerStats->reSends = tp->reSends;
                peerStats->inPacketSkew = tp->inPacketSkew;
                peerStats->outPacketSkew = tp->outPacketSkew;
                peerStats->rateFlag = tp->rateFlag;
                peerStats->natMTU = tp->natMTU;
                peerStats->maxMTU = tp->maxMTU;
                peerStats->maxDgramPackets = tp->maxDgramPackets;
                peerStats->ifDgramPackets = tp->ifDgramPackets;
                peerStats->MTU = tp->MTU;
                peerStats->cwind = tp->cwind;
                peerStats->nDgramPackets = tp->nDgramPackets;
                peerStats->congestSeq = tp->congestSeq;
                peerStats->bytesSent.high = tp->bytesSent.high;
                peerStats->bytesSent.low = tp->bytesSent.low;
                peerStats->bytesReceived.high = tp->bytesReceived.high;
                peerStats->bytesReceived.low = tp->bytesReceived.low;
        }
        MUTEX_EXIT(&rx_peerHashTable_lock);

        return error;
}

void
shutdown_rx(void)
{
    struct rx_serverQueueEntry *np;
    int i, j;
#ifndef KERNEL
    struct rx_call *call;
    struct rx_serverQueueEntry *sq;
#endif /* KERNEL */

    LOCK_RX_INIT;
    if (rxinit_status == 1) {
        UNLOCK_RX_INIT;
        return;                 /* Already shutdown. */
    }
#ifndef KERNEL
    rx_port = 0;
#ifndef AFS_PTHREAD_ENV
    FD_ZERO(&rx_selectMask);
#endif /* AFS_PTHREAD_ENV */
    rxi_dataQuota = RX_MAX_QUOTA;
#ifndef AFS_PTHREAD_ENV
    rxi_StopListener();
#endif /* AFS_PTHREAD_ENV */
    shutdown_rxevent();
    rx_SetEpoch(0);
#ifndef AFS_PTHREAD_ENV
#ifndef AFS_USE_GETTIMEOFDAY
    clock_UnInit();
#endif /* AFS_USE_GETTIMEOFDAY */
#endif /* AFS_PTHREAD_ENV */

    while (!queue_IsEmpty(&rx_freeCallQueue)) {
        call = queue_First(&rx_freeCallQueue, rx_call);
        queue_Remove(call);
        rxi_Free(call, sizeof(struct rx_call));
    }

    while (!queue_IsEmpty(&rx_idleServerQueue)) {
        sq = queue_First(&rx_idleServerQueue, rx_serverQueueEntry);
        queue_Remove(sq);
    }
#endif /* KERNEL */

    {
        struct rx_peer **peer_ptr, **peer_end;
        for (peer_ptr = &rx_peerHashTable[0], peer_end =
             &rx_peerHashTable[rx_hashTableSize]; peer_ptr < peer_end;
             peer_ptr++) {
            struct rx_peer *peer, *next;
            for (peer = *peer_ptr; peer; peer = next) {
                rx_interface_stat_p rpc_stat, nrpc_stat;
                size_t space;
                for (queue_Scan
                     (&peer->rpcStats, rpc_stat, nrpc_stat,
                      rx_interface_stat)) {
                    unsigned int num_funcs;
                    if (!rpc_stat)
                        break;
                    queue_Remove(&rpc_stat->queue_header);
                    queue_Remove(&rpc_stat->all_peers);
                    num_funcs = rpc_stat->stats[0].func_total;
                    space =
                        sizeof(rx_interface_stat_t) +
                        rpc_stat->stats[0].func_total *
                        sizeof(rx_function_entry_v1_t);

                    rxi_Free(rpc_stat, space);
                    MUTEX_ENTER(&rx_rpc_stats);
                    rxi_rpc_peer_stat_cnt -= num_funcs;
                    MUTEX_EXIT(&rx_rpc_stats);
                }
                next = peer->next;
                rxi_FreePeer(peer);
                if (rx_stats_active)
                    rx_MutexDecrement(rx_stats.nPeerStructs, rx_stats_mutex);
            }
        }
    }
    for (i = 0; i < RX_MAX_SERVICES; i++) {
        if (rx_services[i])
            rxi_Free(rx_services[i], sizeof(*rx_services[i]));
    }
    for (i = 0; i < rx_hashTableSize; i++) {
        struct rx_connection *tc, *ntc;
        MUTEX_ENTER(&rx_connHashTable_lock);
        for (tc = rx_connHashTable[i]; tc; tc = ntc) {
            ntc = tc->next;
            for (j = 0; j < RX_MAXCALLS; j++) {
                if (tc->call[j]) {
                    rxi_Free(tc->call[j], sizeof(*tc->call[j]));
                }
            }
            rxi_Free(tc, sizeof(*tc));
        }
        MUTEX_EXIT(&rx_connHashTable_lock);
    }

    MUTEX_ENTER(&freeSQEList_lock);

    while ((np = rx_FreeSQEList)) {
        rx_FreeSQEList = *(struct rx_serverQueueEntry **)np;
        MUTEX_DESTROY(&np->lock);
        rxi_Free(np, sizeof(*np));
    }

    MUTEX_EXIT(&freeSQEList_lock);
    MUTEX_DESTROY(&freeSQEList_lock);
    MUTEX_DESTROY(&rx_freeCallQueue_lock);
    MUTEX_DESTROY(&rx_connHashTable_lock);
    MUTEX_DESTROY(&rx_peerHashTable_lock);
    MUTEX_DESTROY(&rx_serverPool_lock);

    osi_Free(rx_connHashTable,
             rx_hashTableSize * sizeof(struct rx_connection *));
    osi_Free(rx_peerHashTable, rx_hashTableSize * sizeof(struct rx_peer *));

    UNPIN(rx_connHashTable,
          rx_hashTableSize * sizeof(struct rx_connection *));
    UNPIN(rx_peerHashTable, rx_hashTableSize * sizeof(struct rx_peer *));

    rxi_FreeAllPackets();

    MUTEX_ENTER(&rx_quota_mutex);
    rxi_dataQuota = RX_MAX_QUOTA;
    rxi_availProcs = rxi_totalMin = rxi_minDeficit = 0;
    MUTEX_EXIT(&rx_quota_mutex);
    rxinit_status = 1;
    UNLOCK_RX_INIT;
}

#ifdef RX_ENABLE_LOCKS
void
osirx_AssertMine(afs_kmutex_t * lockaddr, char *msg)
{
    if (!MUTEX_ISMINE(lockaddr))
        osi_Panic("Lock not held: %s", msg);
}
#endif /* RX_ENABLE_LOCKS */

#ifndef KERNEL

/*
 * Routines to implement connection specific data.
 */

int
rx_KeyCreate(rx_destructor_t rtn)
{
    int key;
    MUTEX_ENTER(&rxi_keyCreate_lock);
    key = rxi_keyCreate_counter++;
    rxi_keyCreate_destructor = (rx_destructor_t *)
        realloc((void *)rxi_keyCreate_destructor,
                (key + 1) * sizeof(rx_destructor_t));
    rxi_keyCreate_destructor[key] = rtn;
    MUTEX_EXIT(&rxi_keyCreate_lock);
    return key;
}

void
rx_SetSpecific(struct rx_connection *conn, int key, void *ptr)
{
    int i;
    MUTEX_ENTER(&conn->conn_data_lock);
    if (!conn->specific) {
        conn->specific = (void **)malloc((key + 1) * sizeof(void *));
        for (i = 0; i < key; i++)
            conn->specific[i] = NULL;
        conn->nSpecific = key + 1;
        conn->specific[key] = ptr;
    } else if (key >= conn->nSpecific) {
        conn->specific = (void **)
            realloc(conn->specific, (key + 1) * sizeof(void *));
        for (i = conn->nSpecific; i < key; i++)
            conn->specific[i] = NULL;
        conn->nSpecific = key + 1;
        conn->specific[key] = ptr;
    } else {
        if (conn->specific[key] && rxi_keyCreate_destructor[key])
            (*rxi_keyCreate_destructor[key]) (conn->specific[key]);
        conn->specific[key] = ptr;
    }
    MUTEX_EXIT(&conn->conn_data_lock);
}

void *
rx_GetSpecific(struct rx_connection *conn, int key)
{
    void *ptr;
    MUTEX_ENTER(&conn->conn_data_lock);
    if (key >= conn->nSpecific)
        ptr = NULL;
    else
        ptr = conn->specific[key];
    MUTEX_EXIT(&conn->conn_data_lock);
    return ptr;
}

#endif /* !KERNEL */

/*
 * processStats is a queue used to store the statistics for the local
 * process.  Its contents are similar to the contents of the rpcStats
 * queue on a rx_peer structure, but the actual data stored within
 * this queue contains totals across the lifetime of the process (assuming
 * the stats have not been reset) - unlike the per peer structures
 * which can come and go based upon the peer lifetime.
 */

static struct rx_queue processStats = { &processStats, &processStats };

/*
 * peerStats is a queue used to store the statistics for all peer structs.
 * Its contents are the union of all the peer rpcStats queues.
 */

static struct rx_queue peerStats = { &peerStats, &peerStats };

/*
 * rxi_monitor_processStats is used to turn process wide stat collection
 * on and off
 */

static int rxi_monitor_processStats = 0;

/*
 * rxi_monitor_peerStats is used to turn per peer stat collection on and off
 */

static int rxi_monitor_peerStats = 0;

/*
 * rxi_AddRpcStat - given all of the information for a particular rpc
 * call, create (if needed) and update the stat totals for the rpc.
 *
 * PARAMETERS
 *
 * IN stats - the queue of stats that will be updated with the new value
 *
 * IN rxInterface - a unique number that identifies the rpc interface
 *
 * IN currentFunc - the index of the function being invoked
 *
 * IN totalFunc - the total number of functions in this interface
 *
 * IN queueTime - the amount of time this function waited for a thread
 *
 * IN execTime - the amount of time this function invocation took to execute
 *
 * IN bytesSent - the number bytes sent by this invocation
 *
 * IN bytesRcvd - the number bytes received by this invocation
 *
 * IN isServer - if true, this invocation was made to a server
 *
 * IN remoteHost - the ip address of the remote host
 *
 * IN remotePort - the port of the remote host
 *
 * IN addToPeerList - if != 0, add newly created stat to the global peer list
 *
 * INOUT counter - if a new stats structure is allocated, the counter will
 * be updated with the new number of allocated stat structures
 *
 * RETURN CODES
 *
 * Returns void.
 */

static int
rxi_AddRpcStat(struct rx_queue *stats, afs_uint32 rxInterface,
               afs_uint32 currentFunc, afs_uint32 totalFunc,
               struct clock *queueTime, struct clock *execTime,
               afs_hyper_t * bytesSent, afs_hyper_t * bytesRcvd, int isServer,
               afs_uint32 remoteHost, afs_uint32 remotePort,
               int addToPeerList, unsigned int *counter)
{
    int rc = 0;
    rx_interface_stat_p rpc_stat, nrpc_stat;

    /*
     * See if there's already a structure for this interface
     */

    for (queue_Scan(stats, rpc_stat, nrpc_stat, rx_interface_stat)) {
        if ((rpc_stat->stats[0].interfaceId == rxInterface)
            && (rpc_stat->stats[0].remote_is_server == isServer))
            break;
    }

    /*
     * Didn't find a match so allocate a new structure and add it to the
     * queue.
     */

    if (queue_IsEnd(stats, rpc_stat) || (rpc_stat == NULL)
        || (rpc_stat->stats[0].interfaceId != rxInterface)
        || (rpc_stat->stats[0].remote_is_server != isServer)) {
        int i;
        size_t space;

        space =
            sizeof(rx_interface_stat_t) +
            totalFunc * sizeof(rx_function_entry_v1_t);

        rpc_stat = (rx_interface_stat_p) rxi_Alloc(space);
        if (rpc_stat == NULL) {
            rc = 1;
            goto fail;
        }
        *counter += totalFunc;
        for (i = 0; i < totalFunc; i++) {
            rpc_stat->stats[i].remote_peer = remoteHost;
            rpc_stat->stats[i].remote_port = remotePort;
            rpc_stat->stats[i].remote_is_server = isServer;
            rpc_stat->stats[i].interfaceId = rxInterface;
            rpc_stat->stats[i].func_total = totalFunc;
            rpc_stat->stats[i].func_index = i;
            hzero(rpc_stat->stats[i].invocations);
            hzero(rpc_stat->stats[i].bytes_sent);
            hzero(rpc_stat->stats[i].bytes_rcvd);
            rpc_stat->stats[i].queue_time_sum.sec = 0;
            rpc_stat->stats[i].queue_time_sum.usec = 0;
            rpc_stat->stats[i].queue_time_sum_sqr.sec = 0;
            rpc_stat->stats[i].queue_time_sum_sqr.usec = 0;
            rpc_stat->stats[i].queue_time_min.sec = 9999999;
            rpc_stat->stats[i].queue_time_min.usec = 9999999;
            rpc_stat->stats[i].queue_time_max.sec = 0;
            rpc_stat->stats[i].queue_time_max.usec = 0;
            rpc_stat->stats[i].execution_time_sum.sec = 0;
            rpc_stat->stats[i].execution_time_sum.usec = 0;
            rpc_stat->stats[i].execution_time_sum_sqr.sec = 0;
            rpc_stat->stats[i].execution_time_sum_sqr.usec = 0;
            rpc_stat->stats[i].execution_time_min.sec = 9999999;
            rpc_stat->stats[i].execution_time_min.usec = 9999999;
            rpc_stat->stats[i].execution_time_max.sec = 0;
            rpc_stat->stats[i].execution_time_max.usec = 0;
        }
        queue_Prepend(stats, rpc_stat);
        if (addToPeerList) {
            queue_Prepend(&peerStats, &rpc_stat->all_peers);
        }
    }

    /*
     * Increment the stats for this function
     */

    hadd32(rpc_stat->stats[currentFunc].invocations, 1);
    hadd(rpc_stat->stats[currentFunc].bytes_sent, *bytesSent);
    hadd(rpc_stat->stats[currentFunc].bytes_rcvd, *bytesRcvd);
    clock_Add(&rpc_stat->stats[currentFunc].queue_time_sum, queueTime);
    clock_AddSq(&rpc_stat->stats[currentFunc].queue_time_sum_sqr, queueTime);
    if (clock_Lt(queueTime, &rpc_stat->stats[currentFunc].queue_time_min)) {
        rpc_stat->stats[currentFunc].queue_time_min = *queueTime;
    }
    if (clock_Gt(queueTime, &rpc_stat->stats[currentFunc].queue_time_max)) {
        rpc_stat->stats[currentFunc].queue_time_max = *queueTime;
    }
    clock_Add(&rpc_stat->stats[currentFunc].execution_time_sum, execTime);
    clock_AddSq(&rpc_stat->stats[currentFunc].execution_time_sum_sqr,
                execTime);
    if (clock_Lt(execTime, &rpc_stat->stats[currentFunc].execution_time_min)) {
        rpc_stat->stats[currentFunc].execution_time_min = *execTime;
    }
    if (clock_Gt(execTime, &rpc_stat->stats[currentFunc].execution_time_max)) {
        rpc_stat->stats[currentFunc].execution_time_max = *execTime;
    }

  fail:
    return rc;
}

/*
 * rx_IncrementTimeAndCount - increment the times and count for a particular
 * rpc function.
 *
 * PARAMETERS
 *
 * IN peer - the peer who invoked the rpc
 *
 * IN rxInterface - a unique number that identifies the rpc interface
 *
 * IN currentFunc - the index of the function being invoked
 *
 * IN totalFunc - the total number of functions in this interface
 *
 * IN queueTime - the amount of time this function waited for a thread
 *
 * IN execTime - the amount of time this function invocation took to execute
 *
 * IN bytesSent - the number bytes sent by this invocation
 *
 * IN bytesRcvd - the number bytes received by this invocation
 *
 * IN isServer - if true, this invocation was made to a server
 *
 * RETURN CODES
 *
 * Returns void.
 */

void
rx_IncrementTimeAndCount(struct rx_peer *peer, afs_uint32 rxInterface,
                         afs_uint32 currentFunc, afs_uint32 totalFunc,
                         struct clock *queueTime, struct clock *execTime,
                         afs_hyper_t * bytesSent, afs_hyper_t * bytesRcvd,
                         int isServer)
{

    if (!(rxi_monitor_peerStats || rxi_monitor_processStats))
        return;

    MUTEX_ENTER(&rx_rpc_stats);
    MUTEX_ENTER(&peer->peer_lock);

    if (rxi_monitor_peerStats) {
        rxi_AddRpcStat(&peer->rpcStats, rxInterface, currentFunc, totalFunc,
                       queueTime, execTime, bytesSent, bytesRcvd, isServer,
                       peer->host, peer->port, 1, &rxi_rpc_peer_stat_cnt);
    }

    if (rxi_monitor_processStats) {
        rxi_AddRpcStat(&processStats, rxInterface, currentFunc, totalFunc,
                       queueTime, execTime, bytesSent, bytesRcvd, isServer,
                       0xffffffff, 0xffffffff, 0, &rxi_rpc_process_stat_cnt);
    }

    MUTEX_EXIT(&peer->peer_lock);
    MUTEX_EXIT(&rx_rpc_stats);

}

/*
 * rx_MarshallProcessRPCStats - marshall an array of rpc statistics
 *
 * PARAMETERS
 *
 * IN callerVersion - the rpc stat version of the caller.
 *
 * IN count - the number of entries to marshall.
 *
 * IN stats - pointer to stats to be marshalled.
 *
 * OUT ptr - Where to store the marshalled data.
 *
 * RETURN CODES
 *
 * Returns void.
 */
void
rx_MarshallProcessRPCStats(afs_uint32 callerVersion, int count,
                           rx_function_entry_v1_t * stats, afs_uint32 ** ptrP)
{
    int i;
    afs_uint32 *ptr;

    /*
     * We only support the first version
     */
    for (ptr = *ptrP, i = 0; i < count; i++, stats++) {
        *(ptr++) = stats->remote_peer;
        *(ptr++) = stats->remote_port;
        *(ptr++) = stats->remote_is_server;
        *(ptr++) = stats->interfaceId;
        *(ptr++) = stats->func_total;
        *(ptr++) = stats->func_index;
        *(ptr++) = hgethi(stats->invocations);
        *(ptr++) = hgetlo(stats->invocations);
        *(ptr++) = hgethi(stats->bytes_sent);
        *(ptr++) = hgetlo(stats->bytes_sent);
        *(ptr++) = hgethi(stats->bytes_rcvd);
        *(ptr++) = hgetlo(stats->bytes_rcvd);
        *(ptr++) = stats->queue_time_sum.sec;
        *(ptr++) = stats->queue_time_sum.usec;
        *(ptr++) = stats->queue_time_sum_sqr.sec;
        *(ptr++) = stats->queue_time_sum_sqr.usec;
        *(ptr++) = stats->queue_time_min.sec;
        *(ptr++) = stats->queue_time_min.usec;
        *(ptr++) = stats->queue_time_max.sec;
        *(ptr++) = stats->queue_time_max.usec;
        *(ptr++) = stats->execution_time_sum.sec;
        *(ptr++) = stats->execution_time_sum.usec;
        *(ptr++) = stats->execution_time_sum_sqr.sec;
        *(ptr++) = stats->execution_time_sum_sqr.usec;
        *(ptr++) = stats->execution_time_min.sec;
        *(ptr++) = stats->execution_time_min.usec;
        *(ptr++) = stats->execution_time_max.sec;
        *(ptr++) = stats->execution_time_max.usec;
    }
    *ptrP = ptr;
}

/*
 * rx_RetrieveProcessRPCStats - retrieve all of the rpc statistics for
 * this process
 *
 * PARAMETERS
 *
 * IN callerVersion - the rpc stat version of the caller
 *
 * OUT myVersion - the rpc stat version of this function
 *
 * OUT clock_sec - local time seconds
 *
 * OUT clock_usec - local time microseconds
 *
 * OUT allocSize - the number of bytes allocated to contain stats
 *
 * OUT statCount - the number stats retrieved from this process.
 *
 * OUT stats - the actual stats retrieved from this process.
 *
 * RETURN CODES
 *
 * Returns void.  If successful, stats will != NULL.
 */

int
rx_RetrieveProcessRPCStats(afs_uint32 callerVersion, afs_uint32 * myVersion,
                           afs_uint32 * clock_sec, afs_uint32 * clock_usec,
                           size_t * allocSize, afs_uint32 * statCount,
                           afs_uint32 ** stats)
{
    size_t space = 0;
    afs_uint32 *ptr;
    struct clock now;
    int rc = 0;

    *stats = 0;
    *allocSize = 0;
    *statCount = 0;
    *myVersion = RX_STATS_RETRIEVAL_VERSION;

    /*
     * Check to see if stats are enabled
     */

    MUTEX_ENTER(&rx_rpc_stats);
    if (!rxi_monitor_processStats) {
        MUTEX_EXIT(&rx_rpc_stats);
        return rc;
    }

    clock_GetTime(&now);
    *clock_sec = now.sec;
    *clock_usec = now.usec;

    /*
     * Allocate the space based upon the caller version
     *
     * If the client is at an older version than we are,
     * we return the statistic data in the older data format, but
     * we still return our version number so the client knows we
     * are maintaining more data than it can retrieve.
     */

    if (callerVersion >= RX_STATS_RETRIEVAL_FIRST_EDITION) {
        space = rxi_rpc_process_stat_cnt * sizeof(rx_function_entry_v1_t);
        *statCount = rxi_rpc_process_stat_cnt;
    } else {
        /*
         * This can't happen yet, but in the future version changes
         * can be handled by adding additional code here
         */
    }

    if (space > (size_t) 0) {
        *allocSize = space;
        ptr = *stats = (afs_uint32 *) rxi_Alloc(space);

        if (ptr != NULL) {
            rx_interface_stat_p rpc_stat, nrpc_stat;


            for (queue_Scan
                 (&processStats, rpc_stat, nrpc_stat, rx_interface_stat)) {
                /*
                 * Copy the data based upon the caller version
                 */
                rx_MarshallProcessRPCStats(callerVersion,
                                           rpc_stat->stats[0].func_total,
                                           rpc_stat->stats, &ptr);
            }
        } else {
            rc = ENOMEM;
        }
    }
    MUTEX_EXIT(&rx_rpc_stats);
    return rc;
}

/*
 * rx_RetrievePeerRPCStats - retrieve all of the rpc statistics for the peers
 *
 * PARAMETERS
 *
 * IN callerVersion - the rpc stat version of the caller
 *
 * OUT myVersion - the rpc stat version of this function
 *
 * OUT clock_sec - local time seconds
 *
 * OUT clock_usec - local time microseconds
 *
 * OUT allocSize - the number of bytes allocated to contain stats
 *
 * OUT statCount - the number of stats retrieved from the individual
 * peer structures.
 *
 * OUT stats - the actual stats retrieved from the individual peer structures.
 *
 * RETURN CODES
 *
 * Returns void.  If successful, stats will != NULL.
 */

int
rx_RetrievePeerRPCStats(afs_uint32 callerVersion, afs_uint32 * myVersion,
                        afs_uint32 * clock_sec, afs_uint32 * clock_usec,
                        size_t * allocSize, afs_uint32 * statCount,
                        afs_uint32 ** stats)
{
    size_t space = 0;
    afs_uint32 *ptr;
    struct clock now;
    int rc = 0;

    *stats = 0;
    *statCount = 0;
    *allocSize = 0;
    *myVersion = RX_STATS_RETRIEVAL_VERSION;

    /*
     * Check to see if stats are enabled
     */

    MUTEX_ENTER(&rx_rpc_stats);
    if (!rxi_monitor_peerStats) {
        MUTEX_EXIT(&rx_rpc_stats);
        return rc;
    }

    clock_GetTime(&now);
    *clock_sec = now.sec;
    *clock_usec = now.usec;

    /*
     * Allocate the space based upon the caller version
     *
     * If the client is at an older version than we are,
     * we return the statistic data in the older data format, but
     * we still return our version number so the client knows we
     * are maintaining more data than it can retrieve.
     */

    if (callerVersion >= RX_STATS_RETRIEVAL_FIRST_EDITION) {
        space = rxi_rpc_peer_stat_cnt * sizeof(rx_function_entry_v1_t);
        *statCount = rxi_rpc_peer_stat_cnt;
    } else {
        /*
         * This can't happen yet, but in the future version changes
         * can be handled by adding additional code here
         */
    }

    if (space > (size_t) 0) {
        *allocSize = space;
        ptr = *stats = (afs_uint32 *) rxi_Alloc(space);

        if (ptr != NULL) {
            rx_interface_stat_p rpc_stat, nrpc_stat;
            char *fix_offset;

            for (queue_Scan
                 (&peerStats, rpc_stat, nrpc_stat, rx_interface_stat)) {
                /*
                 * We have to fix the offset of rpc_stat since we are
                 * keeping this structure on two rx_queues.  The rx_queue
                 * package assumes that the rx_queue member is the first
                 * member of the structure.  That is, rx_queue assumes that
                 * any one item is only on one queue at a time.  We are
                 * breaking that assumption and so we have to do a little
                 * math to fix our pointers.
                 */

                fix_offset = (char *)rpc_stat;
                fix_offset -= offsetof(rx_interface_stat_t, all_peers);
                rpc_stat = (rx_interface_stat_p) fix_offset;

                /*
                 * Copy the data based upon the caller version
                 */
                rx_MarshallProcessRPCStats(callerVersion,
                                           rpc_stat->stats[0].func_total,
                                           rpc_stat->stats, &ptr);
            }
        } else {
            rc = ENOMEM;
        }
    }
    MUTEX_EXIT(&rx_rpc_stats);
    return rc;
}

/*
 * rx_FreeRPCStats - free memory allocated by
 *                   rx_RetrieveProcessRPCStats and rx_RetrievePeerRPCStats
 *
 * PARAMETERS
 *
 * IN stats - stats previously returned by rx_RetrieveProcessRPCStats or
 * rx_RetrievePeerRPCStats
 *
 * IN allocSize - the number of bytes in stats.
 *
 * RETURN CODES
 *
 * Returns void.
 */

void
rx_FreeRPCStats(afs_uint32 * stats, size_t allocSize)
{
    rxi_Free(stats, allocSize);
}

/*
 * rx_queryProcessRPCStats - see if process rpc stat collection is
 * currently enabled.
 *
 * PARAMETERS
 *
 * RETURN CODES
 *
 * Returns 0 if stats are not enabled != 0 otherwise
 */

int
rx_queryProcessRPCStats(void)
{
    int rc;
    MUTEX_ENTER(&rx_rpc_stats);
    rc = rxi_monitor_processStats;
    MUTEX_EXIT(&rx_rpc_stats);
    return rc;
}

/*
 * rx_queryPeerRPCStats - see if peer stat collection is currently enabled.
 *
 * PARAMETERS
 *
 * RETURN CODES
 *
 * Returns 0 if stats are not enabled != 0 otherwise
 */

int
rx_queryPeerRPCStats(void)
{
    int rc;
    MUTEX_ENTER(&rx_rpc_stats);
    rc = rxi_monitor_peerStats;
    MUTEX_EXIT(&rx_rpc_stats);
    return rc;
}

/*
 * rx_enableProcessRPCStats - begin rpc stat collection for entire process
 *
 * PARAMETERS
 *
 * RETURN CODES
 *
 * Returns void.
 */

void
rx_enableProcessRPCStats(void)
{
    MUTEX_ENTER(&rx_rpc_stats);
    rx_enable_stats = 1;
    rxi_monitor_processStats = 1;
    MUTEX_EXIT(&rx_rpc_stats);
}

/*
 * rx_enablePeerRPCStats - begin rpc stat collection per peer structure
 *
 * PARAMETERS
 *
 * RETURN CODES
 *
 * Returns void.
 */

void
rx_enablePeerRPCStats(void)
{
    MUTEX_ENTER(&rx_rpc_stats);
    rx_enable_stats = 1;
    rxi_monitor_peerStats = 1;
    MUTEX_EXIT(&rx_rpc_stats);
}

/*
 * rx_disableProcessRPCStats - stop rpc stat collection for entire process
 *
 * PARAMETERS
 *
 * RETURN CODES
 *
 * Returns void.
 */

void
rx_disableProcessRPCStats(void)
{
    rx_interface_stat_p rpc_stat, nrpc_stat;
    size_t space;

    MUTEX_ENTER(&rx_rpc_stats);

    /*
     * Turn off process statistics and if peer stats is also off, turn
     * off everything
     */

    rxi_monitor_processStats = 0;
    if (rxi_monitor_peerStats == 0) {
        rx_enable_stats = 0;
    }

    for (queue_Scan(&processStats, rpc_stat, nrpc_stat, rx_interface_stat)) {
        unsigned int num_funcs = 0;
        if (!rpc_stat)
            break;
        queue_Remove(rpc_stat);
        num_funcs = rpc_stat->stats[0].func_total;
        space =
            sizeof(rx_interface_stat_t) +
            rpc_stat->stats[0].func_total * sizeof(rx_function_entry_v1_t);

        rxi_Free(rpc_stat, space);
        rxi_rpc_process_stat_cnt -= num_funcs;
    }
    MUTEX_EXIT(&rx_rpc_stats);
}

/*
 * rx_disablePeerRPCStats - stop rpc stat collection for peers
 *
 * PARAMETERS
 *
 * RETURN CODES
 *
 * Returns void.
 */

void
rx_disablePeerRPCStats(void)
{
    struct rx_peer **peer_ptr, **peer_end;
    int code;

    MUTEX_ENTER(&rx_rpc_stats);

    /*
     * Turn off peer statistics and if process stats is also off, turn
     * off everything
     */

    rxi_monitor_peerStats = 0;
    if (rxi_monitor_processStats == 0) {
        rx_enable_stats = 0;
    }

    MUTEX_ENTER(&rx_peerHashTable_lock);
    for (peer_ptr = &rx_peerHashTable[0], peer_end =
         &rx_peerHashTable[rx_hashTableSize]; peer_ptr < peer_end;
         peer_ptr++) {
        struct rx_peer *peer, *next, *prev;
        for (prev = peer = *peer_ptr; peer; peer = next) {
            next = peer->next;
            code = MUTEX_TRYENTER(&peer->peer_lock);
            if (code) {
                rx_interface_stat_p rpc_stat, nrpc_stat;
                size_t space;
                for (queue_Scan
                     (&peer->rpcStats, rpc_stat, nrpc_stat,
                      rx_interface_stat)) {
                    unsigned int num_funcs = 0;
                    if (!rpc_stat)
                        break;
                    queue_Remove(&rpc_stat->queue_header);
                    queue_Remove(&rpc_stat->all_peers);
                    num_funcs = rpc_stat->stats[0].func_total;
                    space =
                        sizeof(rx_interface_stat_t) +
                        rpc_stat->stats[0].func_total *
                        sizeof(rx_function_entry_v1_t);

                    rxi_Free(rpc_stat, space);
                    rxi_rpc_peer_stat_cnt -= num_funcs;
                }
                MUTEX_EXIT(&peer->peer_lock);
                if (prev == *peer_ptr) {
                    *peer_ptr = next;
                    prev = next;
                } else
                    prev->next = next;
            } else {
                prev = peer;
            }
        }
    }
    MUTEX_EXIT(&rx_peerHashTable_lock);
    MUTEX_EXIT(&rx_rpc_stats);
}

/*
 * rx_clearProcessRPCStats - clear the contents of the rpc stats according
 * to clearFlag
 *
 * PARAMETERS
 *
 * IN clearFlag - flag indicating which stats to clear
 *
 * RETURN CODES
 *
 * Returns void.
 */

void
rx_clearProcessRPCStats(afs_uint32 clearFlag)
{
    rx_interface_stat_p rpc_stat, nrpc_stat;

    MUTEX_ENTER(&rx_rpc_stats);

    for (queue_Scan(&processStats, rpc_stat, nrpc_stat, rx_interface_stat)) {
        unsigned int num_funcs = 0, i;
        num_funcs = rpc_stat->stats[0].func_total;
        for (i = 0; i < num_funcs; i++) {
            if (clearFlag & AFS_RX_STATS_CLEAR_INVOCATIONS) {
                hzero(rpc_stat->stats[i].invocations);
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_BYTES_SENT) {
                hzero(rpc_stat->stats[i].bytes_sent);
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_BYTES_RCVD) {
                hzero(rpc_stat->stats[i].bytes_rcvd);
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_QUEUE_TIME_SUM) {
                rpc_stat->stats[i].queue_time_sum.sec = 0;
                rpc_stat->stats[i].queue_time_sum.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_QUEUE_TIME_SQUARE) {
                rpc_stat->stats[i].queue_time_sum_sqr.sec = 0;
                rpc_stat->stats[i].queue_time_sum_sqr.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_QUEUE_TIME_MIN) {
                rpc_stat->stats[i].queue_time_min.sec = 9999999;
                rpc_stat->stats[i].queue_time_min.usec = 9999999;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_QUEUE_TIME_MAX) {
                rpc_stat->stats[i].queue_time_max.sec = 0;
                rpc_stat->stats[i].queue_time_max.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_EXEC_TIME_SUM) {
                rpc_stat->stats[i].execution_time_sum.sec = 0;
                rpc_stat->stats[i].execution_time_sum.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_EXEC_TIME_SQUARE) {
                rpc_stat->stats[i].execution_time_sum_sqr.sec = 0;
                rpc_stat->stats[i].execution_time_sum_sqr.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_EXEC_TIME_MIN) {
                rpc_stat->stats[i].execution_time_min.sec = 9999999;
                rpc_stat->stats[i].execution_time_min.usec = 9999999;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_EXEC_TIME_MAX) {
                rpc_stat->stats[i].execution_time_max.sec = 0;
                rpc_stat->stats[i].execution_time_max.usec = 0;
            }
        }
    }

    MUTEX_EXIT(&rx_rpc_stats);
}

/*
 * rx_clearPeerRPCStats - clear the contents of the rpc stats according
 * to clearFlag
 *
 * PARAMETERS
 *
 * IN clearFlag - flag indicating which stats to clear
 *
 * RETURN CODES
 *
 * Returns void.
 */

void
rx_clearPeerRPCStats(afs_uint32 clearFlag)
{
    rx_interface_stat_p rpc_stat, nrpc_stat;

    MUTEX_ENTER(&rx_rpc_stats);

    for (queue_Scan(&peerStats, rpc_stat, nrpc_stat, rx_interface_stat)) {
        unsigned int num_funcs = 0, i;
        char *fix_offset;
        /*
         * We have to fix the offset of rpc_stat since we are
         * keeping this structure on two rx_queues.  The rx_queue
         * package assumes that the rx_queue member is the first
         * member of the structure.  That is, rx_queue assumes that
         * any one item is only on one queue at a time.  We are
         * breaking that assumption and so we have to do a little
         * math to fix our pointers.
         */

        fix_offset = (char *)rpc_stat;
        fix_offset -= offsetof(rx_interface_stat_t, all_peers);
        rpc_stat = (rx_interface_stat_p) fix_offset;

        num_funcs = rpc_stat->stats[0].func_total;
        for (i = 0; i < num_funcs; i++) {
            if (clearFlag & AFS_RX_STATS_CLEAR_INVOCATIONS) {
                hzero(rpc_stat->stats[i].invocations);
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_BYTES_SENT) {
                hzero(rpc_stat->stats[i].bytes_sent);
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_BYTES_RCVD) {
                hzero(rpc_stat->stats[i].bytes_rcvd);
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_QUEUE_TIME_SUM) {
                rpc_stat->stats[i].queue_time_sum.sec = 0;
                rpc_stat->stats[i].queue_time_sum.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_QUEUE_TIME_SQUARE) {
                rpc_stat->stats[i].queue_time_sum_sqr.sec = 0;
                rpc_stat->stats[i].queue_time_sum_sqr.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_QUEUE_TIME_MIN) {
                rpc_stat->stats[i].queue_time_min.sec = 9999999;
                rpc_stat->stats[i].queue_time_min.usec = 9999999;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_QUEUE_TIME_MAX) {
                rpc_stat->stats[i].queue_time_max.sec = 0;
                rpc_stat->stats[i].queue_time_max.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_EXEC_TIME_SUM) {
                rpc_stat->stats[i].execution_time_sum.sec = 0;
                rpc_stat->stats[i].execution_time_sum.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_EXEC_TIME_SQUARE) {
                rpc_stat->stats[i].execution_time_sum_sqr.sec = 0;
                rpc_stat->stats[i].execution_time_sum_sqr.usec = 0;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_EXEC_TIME_MIN) {
                rpc_stat->stats[i].execution_time_min.sec = 9999999;
                rpc_stat->stats[i].execution_time_min.usec = 9999999;
            }
            if (clearFlag & AFS_RX_STATS_CLEAR_EXEC_TIME_MAX) {
                rpc_stat->stats[i].execution_time_max.sec = 0;
                rpc_stat->stats[i].execution_time_max.usec = 0;
            }
        }
    }

    MUTEX_EXIT(&rx_rpc_stats);
}

/*
 * rxi_rxstat_userok points to a routine that returns 1 if the caller
 * is authorized to enable/disable/clear RX statistics.
 */
static int (*rxi_rxstat_userok) (struct rx_call * call) = NULL;

void
rx_SetRxStatUserOk(int (*proc) (struct rx_call * call))
{
    rxi_rxstat_userok = proc;
}

int
rx_RxStatUserOk(struct rx_call *call)
{
    if (!rxi_rxstat_userok)
        return 0;
    return rxi_rxstat_userok(call);
}

#ifdef AFS_NT40_ENV
/*
 * DllMain() -- Entry-point function called by the DllMainCRTStartup()
 *     function in the MSVC runtime DLL (msvcrt.dll).
 *
 *     Note: the system serializes calls to this function.
 */
BOOL WINAPI
DllMain(HINSTANCE dllInstHandle,        /* instance handle for this DLL module */
        DWORD reason,                   /* reason function is being called */
        LPVOID reserved)                /* reserved for future use */
{
    switch (reason) {
    case DLL_PROCESS_ATTACH:
        /* library is being attached to a process */
        INIT_PTHREAD_LOCKS;
        return TRUE;

    case DLL_PROCESS_DETACH:
        return TRUE;

    default:
        return FALSE;
    }
}
#endif /* AFS_NT40_ENV */

#ifndef KERNEL
int rx_DumpCalls(FILE *outputFile, char *cookie)
{
#ifdef RXDEBUG_PACKET
#ifdef KDUMP_RX_LOCK
    struct rx_call_rx_lock *c;
#else
    struct rx_call *c;
#endif
#ifdef AFS_NT40_ENV
    int zilch;
    char output[2048];
#define RXDPRINTF sprintf
#define RXDPRINTOUT output
#else
#define RXDPRINTF fprintf
#define RXDPRINTOUT outputFile
#endif

    RXDPRINTF(RXDPRINTOUT, "%s - Start dumping all Rx Calls - count=%u\r\n", cookie, rx_stats.nCallStructs);
#ifdef AFS_NT40_ENV
    WriteFile(outputFile, output, (DWORD)strlen(output), &zilch, NULL);
#endif

    for (c = rx_allCallsp; c; c = c->allNextp) {
        u_short rqc, tqc, iovqc;
        struct rx_packet *p, *np;

        MUTEX_ENTER(&c->lock);
        queue_Count(&c->rq, p, np, rx_packet, rqc);
        queue_Count(&c->tq, p, np, rx_packet, tqc);
        queue_Count(&c->iovq, p, np, rx_packet, iovqc);

        RXDPRINTF(RXDPRINTOUT, "%s - call=0x%p, id=%u, state=%u, mode=%u, conn=%p, epoch=%u, cid=%u, callNum=%u, connFlags=0x%x, flags=0x%x, "
                "rqc=%u,%u, tqc=%u,%u, iovqc=%u,%u, "
                "lstatus=%u, rstatus=%u, error=%d, timeout=%u, "
                "resendEvent=%d, timeoutEvt=%d, keepAliveEvt=%d, delayedAckEvt=%d, delayedAbortEvt=%d, abortCode=%d, abortCount=%d, "
                "lastSendTime=%u, lastRecvTime=%u, lastSendData=%u"
#ifdef RX_ENABLE_LOCKS
                ", refCount=%u"
#endif
#ifdef RX_REFCOUNT_CHECK
                ", refCountBegin=%u, refCountResend=%u, refCountDelay=%u, "
                "refCountAlive=%u, refCountPacket=%u, refCountSend=%u, refCountAckAll=%u, refCountAbort=%u"
#endif
                "\r\n",
                cookie, c, c->call_id, (afs_uint32)c->state, (afs_uint32)c->mode, c->conn, c->conn?c->conn->epoch:0, c->conn?c->conn->cid:0,
                c->callNumber?*c->callNumber:0, c->conn?c->conn->flags:0, c->flags,
                (afs_uint32)c->rqc, (afs_uint32)rqc, (afs_uint32)c->tqc, (afs_uint32)tqc, (afs_uint32)c->iovqc, (afs_uint32)iovqc, 
                (afs_uint32)c->localStatus, (afs_uint32)c->remoteStatus, c->error, c->timeout, 
                c->resendEvent?1:0, c->timeoutEvent?1:0, c->keepAliveEvent?1:0, c->delayedAckEvent?1:0, c->delayedAbortEvent?1:0,
                c->abortCode, c->abortCount, c->lastSendTime, c->lastReceiveTime, c->lastSendData
#ifdef RX_ENABLE_LOCKS
                , (afs_uint32)c->refCount
#endif
#ifdef RX_REFCOUNT_CHECK
                , c->refCDebug[0],c->refCDebug[1],c->refCDebug[2],c->refCDebug[3],c->refCDebug[4],c->refCDebug[5],c->refCDebug[6],c->refCDebug[7]
#endif
                );
        MUTEX_EXIT(&c->lock);

#ifdef AFS_NT40_ENV
        WriteFile(outputFile, output, (DWORD)strlen(output), &zilch, NULL);
#endif
    }
    RXDPRINTF(RXDPRINTOUT, "%s - End dumping all Rx Calls\r\n", cookie);
#ifdef AFS_NT40_ENV
    WriteFile(outputFile, output, (DWORD)strlen(output), &zilch, NULL);
#endif
#endif /* RXDEBUG_PACKET */
    return 0;
}
#endif