Add safety checks on all hostList traversals
[openafs.git] / src / viced / host.c
index 5f2f940..01ebee9 100644 (file)
 #include <afsconfig.h>
 #include <afs/param.h>
 
-RCSID
-    ("$Header$");
 
 #include <stdio.h>
 #include <errno.h>
+#include <string.h>
 #ifdef AFS_NT40_ENV
 #include <fcntl.h>
 #include <winsock2.h>
@@ -26,20 +25,14 @@ RCSID
 #include <netinet/in.h>
 #endif
 
-#ifdef HAVE_STRING_H
-#include <string.h>
-#else
-#ifdef HAVE_STRINGS_H
-#include <strings.h>
-#endif
-#endif
-
 #include <afs/stds.h>
 #include <rx/xdr.h>
 #include <afs/assert.h>
 #include <lwp.h>
 #include <lock.h>
 #include <afs/afsint.h>
+#define FSINT_COMMON_XG
+#include <afs/afscbint.h>
 #include <afs/rxgen_consts.h>
 #include <afs/nfs.h>
 #include <afs/errors.h>
@@ -55,6 +48,7 @@ RCSID
 #include <afs/prs_fs.h>
 #include <afs/auth.h>
 #include <afs/afsutil.h>
+#include <afs/com_err.h>
 #include <rx/rx.h>
 #include <afs/cellconfig.h>
 #include <stdlib.h>
@@ -81,6 +75,7 @@ extern struct afsconf_dir *confDir;   /* config dir object */
 extern int lwps;               /* the max number of server threads */
 extern afsUUID FS_HostUUID;
 
+afsUUID nulluuid;
 int CEs = 0;                   /* active clients */
 int CEBlocks = 0;              /* number of blocks of CEs */
 struct client *CEFree = 0;     /* first free client */
@@ -92,17 +87,14 @@ int rxcon_client_key;
 static struct rx_securityClass *sc = NULL;
 
 static void h_SetupCallbackConn_r(struct host * host);
-static void h_AddHostToHashTable_r(afs_uint32 addr, afs_uint16 port, struct host * host);
-static void h_AddHostToUuidHashTable_r(afsUUID * uuid, struct host * host);
-static int h_DeleteHostFromHashTableByAddr_r(afs_uint32 addr, afs_uint16 port, struct host *host);
+static int h_threadquota(int);
 
 #define CESPERBLOCK 73
 struct CEBlock {               /* block of CESPERBLOCK file entries */
     struct client entry[CESPERBLOCK];
 };
 
-static void h_TossStuff_r(register struct host *host);
-static int hashDelete_r(afs_uint32 addr, afs_uint16 port, struct host *host);
+void h_TossStuff_r(register struct host *host);
 
 /*
  * Make sure the subnet macros have been defined.
@@ -126,7 +118,7 @@ static int hashDelete_r(afs_uint32 addr, afs_uint16 port, struct host *host);
 
 /* get a new block of CEs and chain it on CEFree */
 static void
-GetCEBlock()
+GetCEBlock(void)
 {
     register struct CEBlock *block;
     register int i;
@@ -151,7 +143,7 @@ GetCEBlock()
 
 /* get the next available CE */
 static struct client *
-GetCE()
+GetCE(void)
 {
     register struct client *entry;
 
@@ -165,7 +157,7 @@ GetCE()
     entry = CEFree;
     CEFree = entry->next;
     CEs++;
-    memset((char *)entry, 0, CLIENT_TO_ZERO(entry));
+    memset(entry, 0, CLIENT_TO_ZERO(entry));
     return (entry);
 
 }                              /*GetCE */
@@ -175,6 +167,8 @@ GetCE()
 static void
 FreeCE(register struct client *entry)
 {
+    entry->VenusEpoch = 0;
+    entry->sid = 0;
     entry->next = CEFree;
     CEFree = entry;
     CEs--;
@@ -194,9 +188,9 @@ static struct host *HTFree = 0;     /* first free file entry */
  * to map IP addresses onto host pointers, and another
  * to map host UUIDs onto host pointers.
  */
-static struct h_hashChain *hostHashTable[h_HASHENTRIES];
-static struct h_hashChain *hostUuidHashTable[h_HASHENTRIES];
-#define h_HashIndex(hostip) ((hostip) & (h_HASHENTRIES-1))
+static struct h_AddrHashChain *hostAddrHashTable[h_HASHENTRIES];
+static struct h_UuidHashChain *hostUuidHashTable[h_HASHENTRIES];
+#define h_HashIndex(hostip) (ntohl(hostip) & (h_HASHENTRIES-1))
 #define h_UuidHashIndex(uuidp) (((int)(afs_uuid_hash(uuidp))) & (h_HASHENTRIES-1))
 
 struct HTBlock {               /* block of HTSPERBLOCK file entries */
@@ -206,7 +200,7 @@ struct HTBlock {            /* block of HTSPERBLOCK file entries */
 
 /* get a new block of HTs and chain it on HTFree */
 static void
-GetHTBlock()
+GetHTBlock(void)
 {
     register struct HTBlock *block;
     register int i;
@@ -241,7 +235,7 @@ GetHTBlock()
 
 /* get the next available HT */
 static struct host *
-GetHT()
+GetHT(void)
 {
     register struct host *entry;
 
@@ -251,7 +245,7 @@ GetHT()
     entry = HTFree;
     HTFree = entry->next;
     HTs++;
-    memset((char *)entry, 0, HOST_TO_ZERO(entry));
+    memset(entry, 0, HOST_TO_ZERO(entry));
     return (entry);
 
 }                              /*GetHT */
@@ -267,59 +261,235 @@ FreeHT(register struct host *entry)
 
 }                              /*FreeHT */
 
+afs_int32
+hpr_Initialize(struct ubik_client **uclient)
+{
+    afs_int32 code;
+    struct rx_connection *serverconns[MAXSERVERS];
+    struct rx_securityClass *sc[3];
+    struct afsconf_dir *tdir;
+    struct ktc_token ttoken;
+    afs_int32 scIndex;
+    struct afsconf_cell info;
+    afs_int32 i;
+    char cellstr[64];
+
+    tdir = afsconf_Open(AFSDIR_SERVER_ETC_DIRPATH);
+    if (!tdir) {
+       ViceLog(0, ("hpr_Initialize: Could not open configuration directory: %s", AFSDIR_SERVER_ETC_DIRPATH));
+       return -1;
+    }
+    
+    code = afsconf_GetLocalCell(tdir, cellstr, sizeof(cellstr));
+    if (code) {
+       ViceLog(0, ("hpr_Initialize: Could not get local cell. [%d]", code));
+       afsconf_Close(tdir);
+       return code;
+    }
+    
+    code = afsconf_GetCellInfo(tdir, cellstr, "afsprot", &info);
+    if (code) {
+       ViceLog(0, ("hpr_Initialize: Could not locate cell %s in %s/%s", cellstr, confDir, AFSDIR_CELLSERVDB_FILE));
+       afsconf_Close(tdir);
+       return code;
+    }
+    
+    code = rx_Init(0);
+    if (code) {
+       ViceLog(0, ("hpr_Initialize: Could not initialize rx."));
+       afsconf_Close(tdir);
+        return code;
+    }
+    
+    scIndex = 2;
+    sc[0] = 0;
+    sc[1] = 0;
+    sc[2] = 0;
+    /* Most callers use secLevel==1, however, the fileserver uses secLevel==2
+     * to force use of the KeyFile.  secLevel == 0 implies -noauth was
+     * specified. */
+    if ((afsconf_GetLatestKey(tdir, 0, 0) == 0)) {
+        code = afsconf_ClientAuthSecure(tdir, &sc[2], &scIndex);
+        if (code)
+           ViceLog(0, ("hpr_Initialize: clientauthsecure returns %d %s (so trying noauth)", code, afs_error_message(code)));
+        if (code)
+            scIndex = 0;        /* use noauth */
+        if (scIndex != 2)
+            /* if there was a problem, an unauthenticated conn is returned */
+            sc[scIndex] = sc[2];
+    } else {
+        struct ktc_principal sname;
+        strcpy(sname.cell, info.name);
+        sname.instance[0] = 0;
+        strcpy(sname.name, "afs");
+        code = ktc_GetToken(&sname, &ttoken, sizeof(ttoken), NULL);
+        if (code)
+            scIndex = 0;
+        else {
+            if (ttoken.kvno >= 0 && ttoken.kvno <= 256)
+                /* this is a kerberos ticket, set scIndex accordingly */
+                scIndex = 2;
+            else {
+                ViceLog(0, ("hpr_Initialize: funny kvno (%d) in ticket, proceeding", ttoken.kvno));
+                scIndex = 2;
+            }
+            sc[2] =
+                rxkad_NewClientSecurityObject(rxkad_clear, &ttoken.sessionKey,
+                                              ttoken.kvno, ttoken.ticketLen,
+                                              ttoken.ticket);
+        }
+    }
+    if ((scIndex == 0) && (sc[0] == 0))
+        sc[0] = rxnull_NewClientSecurityObject();
+    if ((scIndex == 0))
+       ViceLog(0, ("hpr_Initialize: Could not get afs tokens, running unauthenticated. [%d]", code));
+    
+    memset(serverconns, 0, sizeof(serverconns));        /* terminate list!!! */
+    for (i = 0; i < info.numServers; i++) {
+        serverconns[i] =
+            rx_NewConnection(info.hostAddr[i].sin_addr.s_addr,
+                             info.hostAddr[i].sin_port, PRSRV, sc[scIndex],
+                             scIndex);
+    }
 
-static short consolePort = 0;
+    code = ubik_ClientInit(serverconns, uclient);
+    if (code) {
+       ViceLog(0, ("hpr_Initialize: ubik client init failed. [%d]", code));
+    }
+    afsconf_Close(tdir);
+    code = rxs_Release(sc[scIndex]);
+    return code;
+}
 
 int
-h_Release(register struct host *host)
+hpr_End(struct ubik_client *uclient)
 {
-    H_LOCK;
-    h_Release_r(host);
-    H_UNLOCK;
+    int code = 0;
+
+    if (uclient) {
+        code = ubik_ClientDestroy(uclient);
+    }
+    return code;
+}
+
+int
+hpr_GetHostCPS(afs_int32 host, prlist *CPS)
+{
+#ifdef AFS_PTHREAD_ENV
+    register afs_int32 code;
+    afs_int32 over;
+    struct ubik_client *uclient = 
+       (struct ubik_client *)pthread_getspecific(viced_uclient_key);
+
+    if (!uclient) {
+        code = hpr_Initialize(&uclient);
+       if (!code) 
+           assert(pthread_setspecific(viced_uclient_key, (void *)uclient) == 0);
+       else
+           return code;
+    }
+
+    over = 0;
+    code = ubik_PR_GetHostCPS(uclient, 0, host, CPS, &over);
+    if (code != PRSUCCESS)
+        return code;
+    if (over) {
+      /* do something about this, probably make a new call */
+      /* don't forget there's a hard limit in the interface */
+        fprintf(stderr,
+                "membership list for host id %d exceeds display limit\n",
+                host);
+    }
     return 0;
+#else
+    return pr_GetHostCPS(host, CPS);
+#endif
 }
 
-/**
- * If this thread does not have a hold on this host AND
- * if other threads also dont have any holds on this host AND
- * If either the HOSTDELETED or CLIENTDELETED flags are set
- * then toss the host
- */
 int
-h_Release_r(register struct host *host)
+hpr_NameToId(namelist *names, idlist *ids)
 {
+#ifdef AFS_PTHREAD_ENV
+    register afs_int32 code;
+    register afs_int32 i;
+    struct ubik_client *uclient = 
+       (struct ubik_client *)pthread_getspecific(viced_uclient_key);
+
+    if (!uclient) {
+        code = hpr_Initialize(&uclient);
+       if (!code)
+           assert(pthread_setspecific(viced_uclient_key, (void *)uclient) == 0);
+       else
+           return code;
+    }
 
-    if (!((host)->holds[h_holdSlot()] & ~h_holdbit())) {
-       if (!h_OtherHolds_r(host)) {
-           /* must avoid masking this until after h_OtherHolds_r runs
-            * but it should be run before h_TossStuff_r */
-           (host)->holds[h_holdSlot()] &= ~h_holdbit();
-           if ((host->hostFlags & HOSTDELETED)
-               || (host->hostFlags & CLIENTDELETED)) {
-               h_TossStuff_r(host);
-           }
-       } else
-           (host)->holds[h_holdSlot()] &= ~h_holdbit();
-    } else
-       (host)->holds[h_holdSlot()] &= ~h_holdbit();
+    for (i = 0; i < names->namelist_len; i++)
+        stolower(names->namelist_val[i]);
+    code = ubik_PR_NameToID(uclient, 0, names, ids);
+    return code;
+#else
+    return pr_NameToId(names, ids);
+#endif
+}
 
-    return 0;
+int
+hpr_IdToName(idlist *ids, namelist *names)
+{
+#ifdef AFS_PTHREAD_ENV
+    register afs_int32 code;
+    struct ubik_client *uclient = 
+       (struct ubik_client *)pthread_getspecific(viced_uclient_key);
+    
+    if (!uclient) {
+        code = hpr_Initialize(&uclient);
+       if (!code)
+           assert(pthread_setspecific(viced_uclient_key, (void *)uclient) == 0);
+       else
+           return code;
+    }
+
+    code = ubik_PR_IDToName(uclient, 0, ids, names);
+    return code;
+#else
+    return pr_IdToName(ids, names);
+#endif
 }
 
 int
-h_OtherHolds_r(register struct host *host)
+hpr_GetCPS(afs_int32 id, prlist *CPS)
 {
-    register int i, bit, slot;
-    bit = h_holdbit();
-    slot = h_holdSlot();
-    for (i = 0; i < h_maxSlots; i++) {
-       if (host->holds[i] != ((i == slot) ? bit : 0)) {
-           return 1;
-       }
+#ifdef AFS_PTHREAD_ENV
+    register afs_int32 code;
+    afs_int32 over;
+    struct ubik_client *uclient = 
+       (struct ubik_client *)pthread_getspecific(viced_uclient_key);
+
+    if (!uclient) {
+        code = hpr_Initialize(&uclient);
+       if (!code)
+           assert(pthread_setspecific(viced_uclient_key, (void *)uclient) == 0);
+       else
+           return code;
+    }
+
+    over = 0;
+    code = ubik_PR_GetCPS(uclient, 0, id, CPS, &over);
+    if (code != PRSUCCESS)
+        return code;
+    if (over) {
+      /* do something about this, probably make a new call */
+      /* don't forget there's a hard limit in the interface */
+        fprintf(stderr, "membership list for id %d exceeds display limit\n",
+                id);
     }
     return 0;
+#else
+    return pr_GetCPS(id, CPS);
+#endif
 }
 
+static short consolePort = 0;
+
 int
 h_Lock_r(register struct host *host)
 {
@@ -464,9 +634,10 @@ h_gethostcps_r(register struct host *host, register afs_int32 now)
     host->cpsCall = slept ? (FT_ApproxTime()) : (now);
 
     H_UNLOCK;
-    code = pr_GetHostCPS(ntohl(host->host), &host->hcps);
+    code = hpr_GetHostCPS(ntohl(host->host), &host->hcps);
     H_LOCK;
     if (code) {
+        char hoststr[16];
        /*
         * Although ubik_Call (called by pr_GetHostCPS) traverses thru all protection servers
         * and reevaluates things if no sync server or quorum is found we could still end up
@@ -488,13 +659,13 @@ h_gethostcps_r(register struct host *host, register afs_int32 now)
             */
            host->hcpsfailed = 1;
            ViceLog(0,
-                   ("Warning:  GetHostCPS failed (%d) for %x; will retry\n",
-                    code, host->host));
+                   ("Warning:  GetHostCPS failed (%d) for %x (%s:%d); will retry\n",
+                    code, host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
        } else {
            host->hcpsfailed = 0;
            ViceLog(1,
-                   ("gethost:  GetHostCPS failed (%d) for %x; ignored\n",
-                    code, host->host));
+                   ("gethost:  GetHostCPS failed (%d) for %x (%s:%d); ignored\n",
+                    code, host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
        }
        if (host->hcps.prlist_val)
            free(host->hcps.prlist_val);
@@ -520,15 +691,13 @@ h_gethostcps_r(register struct host *host, register afs_int32 now)
 void
 h_flushhostcps(register afs_uint32 hostaddr, register afs_uint16 hport)
 {
-    register struct host *host;
-    int held = 0;
+    struct host *host;
 
     H_LOCK;
-    host = h_Lookup_r(hostaddr, hport, &held);
+    h_Lookup_r(hostaddr, hport, &host);
     if (host) {
        host->hcpsfailed = 1;
-       if (!held)
-           h_Release_r(host);
+       h_Release_r(host);
     }
     H_UNLOCK;
     return;
@@ -556,7 +725,7 @@ h_Alloc_r(register struct rx_connection *r_con)
     host->host = rxr_HostOf(r_con);
     host->port = rxr_PortOf(r_con);
 
-    h_AddHostToHashTable_r(host->host, host->port, host);
+    h_AddHostToAddrHashTable_r(host->host, host->port, host);
 
     if (consolePort == 0) {    /* find the portal number for console */
 #if    defined(AFS_OSF_ENV)
@@ -615,33 +784,38 @@ h_SetupCallbackConn_r(struct host * host)
     rx_SetConnHardDeadTime(host->callback_rxcon, AFS_HARDDEADTIME);
 }
 
-/* Lookup a host given an IP address and UDP port number. */
-/* hostaddr and hport are in network order */
-/* Note: host should be released by caller if 0 == *heldp and non-null */
-/* hostaddr and hport are in network order */
-struct host *
-h_Lookup_r(afs_uint32 haddr, afs_uint16 hport, int *heldp)
+/* h_Lookup_r
+ * Lookup a host given an IP address and UDP port number.
+ * hostaddr and hport are in network order
+ * hostaddr and hport are in network order
+ * On return, refCount is incremented.
+ */
+int
+h_Lookup_r(afs_uint32 haddr, afs_uint16 hport, struct host **hostp)
 {
     afs_int32 now;
-    struct host *host = 0;
-    struct h_hashChain *chain;
+    struct host *host = NULL;
+    struct h_AddrHashChain *chain;
     int index = h_HashIndex(haddr);
     extern int hostaclRefresh;
 
   restart:
-    for (chain = hostHashTable[index]; chain; chain = chain->next) {
+    for (chain = hostAddrHashTable[index]; chain; chain = chain->next) {
        host = chain->hostPtr;
        assert(host);
        if (!(host->hostFlags & HOSTDELETED) && chain->addr == haddr
            && chain->port == hport) {
-           *heldp = h_Held_r(host);
-           if (!*heldp)
-               h_Hold_r(host);
+           if ((host->hostFlags & HWHO_INPROGRESS) && 
+               h_threadquota(host->lock.num_waiting)) {
+               *hostp = 0;
+               return VBUSY;
+           }
+           h_Hold_r(host);
            h_Lock_r(host);
            if (host->hostFlags & HOSTDELETED) {
                h_Unlock_r(host);
-               if (!*heldp)
-                   h_Release_r(host);
+               h_Release_r(host);
+               host = NULL;
                goto restart;
            }
            h_Unlock_r(host);
@@ -653,7 +827,7 @@ h_Lookup_r(afs_uint32 haddr, afs_uint16 hport, int *heldp)
                 * first time that the host is added to a group.  Also
                 * here we also retry on previous legitimate hcps failures.
                 *
-                * If we get here we still have a host hold.
+                * If we get here refCount is elevated.
                 */
                h_gethostcps_r(host, now);
            }
@@ -661,8 +835,8 @@ h_Lookup_r(afs_uint32 haddr, afs_uint16 hport, int *heldp)
        }
        host = NULL;
     }
-    return host;
-
+    *hostp = host;
+    return 0;
 }                              /*h_Lookup */
 
 /* Lookup a host given its UUID. */
@@ -670,7 +844,7 @@ struct host *
 h_LookupUuid_r(afsUUID * uuidp)
 {
     struct host *host = 0;
-    struct h_hashChain *chain;
+    struct h_UuidHashChain *chain;
     int index = h_UuidHashIndex(uuidp);
 
     for (chain = hostUuidHashTable[index]; chain; chain = chain->next) {
@@ -678,44 +852,33 @@ h_LookupUuid_r(afsUUID * uuidp)
        assert(host);
        if (!(host->hostFlags & HOSTDELETED) && host->interface
            && afs_uuid_equal(&host->interface->uuid, uuidp)) {
-           break;
+            return host;
        }
-       host = NULL;
     }
-    return host;
-
+    return NULL;
 }                              /*h_Lookup */
 
 
-/*
- * h_Hold_r: Establish a hold by the current LWP on this host--the host
- * or its clients will not be physically deleted until all holds have
- * been released.
- * NOTE: h_Hold_r is a macro defined in host.h.
- */
-
 /* h_TossStuff_r:  Toss anything in the host structure (the host or
  * clients marked for deletion.  Called from h_Release_r ONLY.
  * To be called, there must be no holds, and either host->deleted
  * or host->clientDeleted must be set.
  */
-static void
+void
 h_TossStuff_r(register struct host *host)
 {
     register struct client **cp, *client;
-    int i;
 
     /* if somebody still has this host held */
-    for (i = 0; (i < h_maxSlots) && (!(host)->holds[i]); i++);
-    if (i != h_maxSlots)
+    if (host->refCount > 0)
        return;
 
     /* if somebody still has this host locked */
     if (h_NBLock_r(host) != 0) {
        char hoststr[16];
        ViceLog(0,
-               ("Warning:  h_TossStuff_r failed; Host %s:%d was locked.\n",
-                afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
+               ("Warning:  h_TossStuff_r failed; Host %" AFS_PTR_FMT " (%s:%d) was locked.\n",
+                host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
        return;
     } else {
        h_Unlock_r(host);
@@ -729,8 +892,8 @@ h_TossStuff_r(register struct host *host)
            if (code < 0) {
                char hoststr[16];
                ViceLog(0,
-                       ("Warning: h_TossStuff_r failed: Host %s:%d client %x was locked.\n",
-                        afs_inet_ntoa_r(host->host, hoststr),
+                       ("Warning: h_TossStuff_r failed: Host %" AFS_PTR_FMT " (%s:%d) client %x was locked.\n",
+                        host, afs_inet_ntoa_r(host->host, hoststr),
                         ntohs(host->port), client));
                return;
            }
@@ -738,8 +901,8 @@ h_TossStuff_r(register struct host *host)
            if (client->refCount) {
                char hoststr[16];
                ViceLog(0,
-                       ("Warning: h_TossStuff_r failed: Host %s:%d client %x refcount %d.\n",
-                        afs_inet_ntoa_r(host->host, hoststr),
+                       ("Warning: h_TossStuff_r failed: Host %" AFS_PTR_FMT " (%s:%d) client %x refcount %d.\n",
+                        host, afs_inet_ntoa_r(host->host, hoststr),
                         ntohs(host->port), client, client->refCount));
                /* This is the same thing we do if the host is locked */
                ReleaseWriteLock(&client->lock);
@@ -749,9 +912,6 @@ h_TossStuff_r(register struct host *host)
            if ((client->ViceId != ANONYMOUSID) && client->CPS.prlist_val)
                free(client->CPS.prlist_val);
            client->CPS.prlist_val = NULL;
-           if (client->tcon) {
-               rx_SetSpecific(client->tcon, rxcon_client_key, (void *)0);
-           }
            CurrentConnections--;
            *cp = client->next;
            ReleaseWriteLock(&client->lock);
@@ -764,9 +924,7 @@ h_TossStuff_r(register struct host *host)
     host->hostFlags &= ~CLIENTDELETED;
 
     if (host->hostFlags & HOSTDELETED) {
-       register struct h_hashChain **hp, *th;
        register struct rx_connection *rxconn;
-       afsUUID *uuidp;
        struct AddrPort hostAddrPort;
        int i;
 
@@ -774,16 +932,6 @@ h_TossStuff_r(register struct host *host)
            Console--;
        if ((rxconn = host->callback_rxcon)) {
            host->callback_rxcon = (struct rx_connection *)0;
-           /*
-            * If rx_DestroyConnection calls h_FreeConnection we will
-            * deadlock on the host_glock_mutex. Work around the problem
-            * by unhooking the client from the connection before
-            * destroying the connection.
-            */
-           client = rx_GetSpecific(rxconn, rxcon_client_key);
-           if (client && client->tcon == rxconn)
-               client->tcon = NULL;
-           rx_SetSpecific(rxconn, rxcon_client_key, (void *)0);
            rx_DestroyConnection(rxconn);
        }
        if (host->hcps.prlist_val)
@@ -795,82 +943,51 @@ h_TossStuff_r(register struct host *host)
 
        /* if alternate addresses do not exist */
        if (!(host->interface)) {
-           for (hp = &hostHashTable[h_HashIndex(host->host)]; (th = *hp);
-                hp = &th->next) {
-               assert(th->hostPtr);
-               if (th->hostPtr == host) {
-                   *hp = th->next;
-                   h_DeleteList_r(host);
-                   FreeHT(host);
-                   free(th);
-                   break;
-               }
-           }
+           h_DeleteHostFromAddrHashTable_r(host->host, host->port, host);
        } else {
-           /* delete all hash entries for the UUID */
-           uuidp = &host->interface->uuid;
-           for (hp = &hostUuidHashTable[h_UuidHashIndex(uuidp)]; (th = *hp);
-                hp = &th->next) {
-               assert(th->hostPtr);
-               if (th->hostPtr == host) {
-                   *hp = th->next;
-                   free(th);
-                   break;
-               }
-           }
-           /* delete all hash entries for alternate addresses */
-           assert(host->interface->numberOfInterfaces > 0);
+            h_DeleteHostFromUuidHashTable_r(host);
+           h_DeleteHostFromAddrHashTable_r(host->host, host->port, host);
+           /* delete the hash entry for each valid alternate addresses */
            for (i = 0; i < host->interface->numberOfInterfaces; i++) {
                hostAddrPort = host->interface->interface[i];
-
-               for (hp = &hostHashTable[h_HashIndex(hostAddrPort.addr)]; (th = *hp);
-                    hp = &th->next) {
-                   assert(th->hostPtr);
-                   if (th->hostPtr == host) {
-                       *hp = th->next;
-                       free(th);
-                       break;
-                   }
-               }
+                /* 
+                 * if the interface addr/port is the primary, we already
+                 * removed it.  If the addr/port is not valid, its not
+                 * in the hash table.
+                 */
+                if (hostAddrPort.valid &&
+                    (host->host != hostAddrPort.addr ||
+                     host->port != hostAddrPort.port))
+                    h_DeleteHostFromAddrHashTable_r(hostAddrPort.addr, hostAddrPort.port, host);
            }
            free(host->interface);
            host->interface = NULL;
-           h_DeleteList_r(host);       /* remove host from global host List */
-           FreeHT(host);
        }                       /* if alternate address exists */
+
+        h_DeleteList_r(host);  /* remove host from global host List */
+        FreeHT(host);
     }
 }                              /*h_TossStuff_r */
 
 
-/* Called by rx when a server connection disappears */
-int
-h_FreeConnection(struct rx_connection *tcon)
-{
-    register struct client *client;
-
-    client = (struct client *)rx_GetSpecific(tcon, rxcon_client_key);
-    if (client) {
-       H_LOCK;
-       if (client->tcon == tcon)
-           client->tcon = NULL;
-       H_UNLOCK;
-    }
-    return 0;
-}                              /*h_FreeConnection */
-
 
 /* h_Enumerate: Calls (*proc)(host, held, param) for at least each host in the
  * system at the start of the enumeration (perhaps more).  Hosts may be deleted
- * (have delete flag set); ditto for clients.  (*proc) is always called with
- * host h_held().  The hold state of the host with respect to this lwp is passed
- * to (*proc) as the param held.  The proc should return 0 if the host should be
- * released, 1 if it should be held after enumeration.
+ * (have delete flag set); ditto for clients.  refCount is always incremented
+ * before (*proc) is called.  The param flags is passed to (*proc) as the
+ * param flags, permitting (*proc) to stop the enumeration (BAIL).
+ *
+ * Needed?  Why not always h_Hold_r and h_Release_r in (*proc), or even -never-
+ * h_Hold_r or h_Release_r in (*proc)?
+ *
+ * **The proc should return 0 if the host should be released, 1 if it should
+ * be held after enumeration.
  */
 void
-h_Enumerate(int (*proc) (), char *param)
+h_Enumerate(int (*proc) (struct host*, int, void *), void *param)
 {
     register struct host *host, **list;
-    register int *held;
+    register int *flags;
     register int i, count;
 
     H_LOCK;
@@ -880,118 +997,216 @@ h_Enumerate(int (*proc) (), char *param)
     }
     list = (struct host **)malloc(hostCount * sizeof(struct host *));
     if (!list) {
-       ViceLog(0, ("Failed malloc in h_Enumerate\n"));
+       ViceLog(0, ("Failed malloc in h_Enumerate (list)\n"));
        assert(0);
     }
-    held = (int *)malloc(hostCount * sizeof(int));
-    if (!held) {
-       ViceLog(0, ("Failed malloc in h_Enumerate\n"));
+    flags = (int *)malloc(hostCount * sizeof(int));
+    if (!flags) {
+       ViceLog(0, ("Failed malloc in h_Enumerate (flags)\n"));
        assert(0);
     }
-    for (count = 0, host = hostList; host; host = host->next, count++) {
+    for (count = 0, host = hostList; host && count < hostCount; host = host->next, count++) {
        list[count] = host;
-       if (!(held[count] = h_Held_r(host)))
-           h_Hold_r(host);
+       h_Hold_r(host);
+    }
+    if (count != hostCount) {
+       ViceLog(0, ("h_Enumerate found %d of %d hosts\n", count, hostCount));
+    } else if (host != NULL) {
+       ViceLog(0, ("h_Enumerate found more than %d hosts\n", hostCount));
+       ShutDownAndCore(PANIC);
     }
-    assert(count == hostCount);
     H_UNLOCK;
     for (i = 0; i < count; i++) {
-       held[i] = (*proc) (list[i], held[i], param);
-       if (!H_ENUMERATE_ISSET_HELD(held[i]))
-           h_Release(list[i]); /* this might free up the host */
+       flags[i] = (*proc) (list[i], flags[i], param);
+       h_Release_r(list[i]);
        /* bail out of the enumeration early */
-       if (H_ENUMERATE_ISSET_BAIL(held[i]))
+       if (H_ENUMERATE_ISSET_BAIL(flags[i]))
            break;
     }
     free((void *)list);
-    free((void *)held);
-}                              /*h_Enumerate */
+    free((void *)flags);
+}      /* h_Enumerate */
+
 
 /* h_Enumerate_r (revised):
- * Calls (*proc)(host, held, param) for each host in hostList, starting
- * at enumstart
- * Hosts may be deleted (have delete flag set); ditto for clients.
- * (*proc) is always called with
- * host h_held() and the global host lock (H_LOCK) locked.The hold state of the
- * host with respect to this lwp is passed to (*proc) as the param held.
- * The proc should return 0 if the host should be released, 1 if it should
+ * Calls (*proc)(host, flags, param) for each host in hostList, starting
+ * at enumstart. Called only under H_LOCK.  Hosts may be deleted (have
+ * delete flag set); ditto for clients.  refCount is always incremented
+ * before (*proc) is called.  The param flags is passed to (*proc) as the
+ * param flags, permitting (*proc) to stop the enumeration (BAIL).
+ *
+ * Needed?  Why not always h_Hold_r and h_Release_r in (*proc), or even -never-
+ * h_Hold_r or h_Release_r in (*proc)?
+ *
+ * **The proc should return 0 if the host should be released, 1 if it should
  * be held after enumeration.
  */
 void
-h_Enumerate_r(int (*proc) (), struct host *enumstart, char *param)
+h_Enumerate_r(int (*proc) (struct host *, int, void *), 
+             struct host *enumstart, void *param)
 {
     register struct host *host, *next;
-    register int held, nheld;
+    int flags = 0;
+    int nflags = 0;
+    int count;
 
     if (hostCount == 0) {
        return;
     }
-    if (enumstart && !(held = h_Held_r(enumstart)))
-       h_Hold_r(enumstart); 
-    for (host = enumstart; host; host = next, held = nheld) {
+    h_Hold_r(enumstart);
+    for (count = 0, host = enumstart; host && count < hostCount; host = next, flags = nflags, count++) {
        next = host->next;
-       if (next && !(nheld = h_Held_r(next)) && !H_ENUMERATE_ISSET_BAIL(held))
+       if (next && !H_ENUMERATE_ISSET_BAIL(flags))
            h_Hold_r(next);
-       held = (*proc) (host, held, param);
-       if (!H_ENUMERATE_ISSET_HELD(held))
+       flags = (*proc) (host, flags, param);
+       if (H_ENUMERATE_ISSET_BAIL(flags)) {
            h_Release_r(host); /* this might free up the host */
-       if (H_ENUMERATE_ISSET_BAIL(held))
            break;
+       }
+       h_Release_r(host); /* this might free up the host */
     }
-}                              /*h_Enumerate_r */
+    if (host != NULL) {
+       ViceLog(0, ("h_Enumerate_r found more than %d hosts\n", hostCount));
+       ShutDownAndCore(PANIC);
+    }
+}      /*h_Enumerate_r */
+
 
 /* inserts a new HashChain structure corresponding to this UUID */
-static void
+void
 h_AddHostToUuidHashTable_r(struct afsUUID *uuid, struct host *host)
 {
     int index;
-    struct h_hashChain *chain;
+    struct h_UuidHashChain *chain;
+    char uuid1[128], uuid2[128];
+    char hoststr[16];
 
     /* hash into proper bucket */
     index = h_UuidHashIndex(uuid);
 
+    /* don't add the same entry multiple times */
+    for (chain = hostUuidHashTable[index]; chain; chain = chain->next) {
+       if (!chain->hostPtr)
+           continue;
+
+       if (chain->hostPtr->interface && 
+           afs_uuid_equal(&chain->hostPtr->interface->uuid, uuid)) {
+           if (LogLevel >= 125) {
+               afsUUID_to_string(&chain->hostPtr->interface->uuid, uuid1, 
+                                 127);
+               afsUUID_to_string(uuid, uuid2, 127);
+               ViceLog(125, ("h_AddHostToUuidHashTable_r: host %" AFS_PTR_FMT " (uuid %s) exists as %s:%d (uuid %s)\n", 
+                             host, uuid1,
+                             afs_inet_ntoa_r(chain->hostPtr->host, hoststr), 
+                             ntohs(chain->hostPtr->port), uuid2));
+           }
+           return;
+       }
+    }
+
     /* insert into beginning of list for this bucket */
-    chain = (struct h_hashChain *)malloc(sizeof(struct h_hashChain));
+    chain = (struct h_UuidHashChain *)malloc(sizeof(struct h_UuidHashChain));
     if (!chain) {
        ViceLog(0, ("Failed malloc in h_AddHostToUuidHashTable_r\n"));
        assert(0);
     }
-    assert(chain);
     chain->hostPtr = host;
     chain->next = hostUuidHashTable[index];
     hostUuidHashTable[index] = chain;
+         if (LogLevel < 125)
+              return;
+     afsUUID_to_string(uuid, uuid2, 127);
+     ViceLog(125, 
+            ("h_AddHostToUuidHashTable_r: host %" AFS_PTR_FMT " (%s:%d) added as uuid %s\n",
+             host, afs_inet_ntoa_r(chain->hostPtr->host, hoststr), 
+             ntohs(chain->hostPtr->port), uuid));
 }
 
+/* deletes a HashChain structure corresponding to this host */
+int
+h_DeleteHostFromUuidHashTable_r(struct host *host)
+{
+     int index;
+     register struct h_UuidHashChain **uhp, *uth;
+     char uuid1[128];
+     char hoststr[16];
+     if (!host->interface)
+       return 0;
+     /* hash into proper bucket */
+     index = h_UuidHashIndex(&host->interface->uuid);
+     
+     if (LogLevel >= 125)
+        afsUUID_to_string(&host->interface->uuid, uuid1, 127);
+     for (uhp = &hostUuidHashTable[index]; (uth = *uhp); uhp = &uth->next) {
+         assert(uth->hostPtr);
+        if (uth->hostPtr == host) {
+            ViceLog(125, 
+                    ("h_DeleteHostFromUuidHashTable_r: host %" AFS_PTR_FMT " (uuid %s %s:%d)\n",
+                     host, uuid1, afs_inet_ntoa_r(host->host, hoststr), 
+                     ntohs(host->port)));
+            *uhp = uth->next;
+            free(uth);
+            return 1;
+        }
+     }
+     ViceLog(125, 
+            ("h_DeleteHostFromUuidHashTable_r: host %" AFS_PTR_FMT " (uuid %s %s:%d) not found\n",
+             host, uuid1, afs_inet_ntoa_r(host->host, hoststr), 
+             ntohs(host->port)));
+     return 0;
+}
 
 /* inserts a new HashChain structure corresponding to this address */
-static void
-h_AddHostToHashTable_r(afs_uint32 addr, afs_uint16 port, struct host *host)
+void
+h_AddHostToAddrHashTable_r(afs_uint32 addr, afs_uint16 port, struct host *host)
 {
     int index;
-    struct h_hashChain *chain;
+    struct h_AddrHashChain *chain;
+    char hoststr[16], hoststr2[16];
 
     /* hash into proper bucket */
     index = h_HashIndex(addr);
 
+    /* don't add the same entry multiple times */
+    for (chain = hostAddrHashTable[index]; chain; chain = chain->next) {
+       if (chain->hostPtr == host) {
+           if (chain->addr != addr || chain->port != port) {
+               ViceLog(0, 
+                       ("h_AddHostToAddrHashTable_r: host %" AFS_PTR_FMT " exists as %s:%d when adding %s:%d\n",
+                        host, afs_inet_ntoa_r(chain->addr, hoststr), 
+                        ntohs(chain->port), afs_inet_ntoa_r(addr, hoststr2), 
+                        ntohs(port)));
+           } else
+               ViceLog(125, 
+                       ("h_AddHostToAddrHashTable_r: host %" AFS_PTR_FMT " (%s:%d) already hashed\n",
+                        host, afs_inet_ntoa_r(chain->addr, hoststr), 
+                        ntohs(chain->port)));
+           
+           return;
+       }
+    }
+
     /* insert into beginning of list for this bucket */
-    chain = (struct h_hashChain *)malloc(sizeof(struct h_hashChain));
+    chain = (struct h_AddrHashChain *)malloc(sizeof(struct h_AddrHashChain));
     if (!chain) {
-       ViceLog(0, ("Failed malloc in h_AddHostToHashTable_r\n"));
+       ViceLog(0, ("Failed malloc in h_AddHostToAddrHashTable_r\n"));
        assert(0);
     }
     chain->hostPtr = host;
-    chain->next = hostHashTable[index];
+    chain->next = hostAddrHashTable[index];
     chain->addr = addr;
     chain->port = port;
-    hostHashTable[index] = chain;
-
+    hostAddrHashTable[index] = chain;
+    ViceLog(125, ("h_AddHostToAddrHashTable_r: host %" AFS_PTR_FMT " added as %s:%d\n",
+                 host, afs_inet_ntoa_r(addr, hoststr), ntohs(port)));
 }
 
 /*
- * This is called with host locked and held. At this point, the
- * hostHashTable should not be having entries for the alternate
- * interfaces. This function has to insert these entries in the
- * hostHashTable.
+ * This is called with host locked and held. 
+ * It is called to either validate or add an additional interface
+ * address/port on the specified host.  
  *
  * All addresses are in network byte order.
  */
@@ -1000,58 +1215,65 @@ addInterfaceAddr_r(struct host *host, afs_uint32 addr, afs_uint16 port)
 {
     int i;
     int number;
-    int found;
     struct Interface *interface;
     char hoststr[16], hoststr2[16];
-
+                                                   
     assert(host);
     assert(host->interface);
 
-    ViceLog(125, ("addInterfaceAddr : host %s:%d addr %s:%d\n", 
-                  afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port), 
-                  afs_inet_ntoa_r(addr, hoststr2), ntohs(port)));
-
     /*
      * Make sure this address is on the list of known addresses
      * for this host.
      */
     number = host->interface->numberOfInterfaces;
-    for (i = 0, found = 0; i < number && !found; i++) {
+    for (i = 0; i < number; i++) {
        if (host->interface->interface[i].addr == addr &&
-           host->interface->interface[i].port == port)
-           found = 1;
-    }
-    if (!found) {
-       interface = (struct Interface *)
-           malloc(sizeof(struct Interface) + (sizeof(struct AddrPort) * number));
-       if (!interface) {
-           ViceLog(0, ("Failed malloc in addInterfaceAddr_r\n"));
-           assert(0);
-       }
-       interface->numberOfInterfaces = number + 1;
-       interface->uuid = host->interface->uuid;
-       for (i = 0; i < number; i++)
-           interface->interface[i] = host->interface->interface[i];
-       interface->interface[number].addr = addr;
-       interface->interface[number].port = port;
-       free(host->interface);
-       host->interface = interface;
+             host->interface->interface[i].port == port) {
+           ViceLog(125, 
+                   ("addInterfaceAddr : found host %" AFS_PTR_FMT " (%s:%d) adding %s:%d%s\n",
+                    host, afs_inet_ntoa_r(host->host, hoststr), 
+                    ntohs(host->port), afs_inet_ntoa_r(addr, hoststr2), 
+                    ntohs(port), host->interface->interface[i].valid ? "" : 
+                    ", validating"));
+     
+           if (host->interface->interface[i].valid == 0) {
+               host->interface->interface[i].valid = 1;
+               h_AddHostToAddrHashTable_r(addr, port, host);
+           }
+           return 0;
+        }
     }
 
-    /*
-     * Create a hash table entry for this address
-     */
-    h_AddHostToHashTable_r(addr, port, host);
-
+    ViceLog(125, ("addInterfaceAddr : host %" AFS_PTR_FMT " (%s:%d) adding %s:%d\n", 
+                 host, afs_inet_ntoa_r(host->host, hoststr), 
+                 ntohs(host->port), afs_inet_ntoa_r(addr, hoststr2), 
+                 ntohs(port)));
+    
+    interface = (struct Interface *)
+       malloc(sizeof(struct Interface) + (sizeof(struct AddrPort) * number));
+    if (!interface) {
+       ViceLog(0, ("Failed malloc in addInterfaceAddr_r\n"));
+       assert(0);
+    }
+    interface->numberOfInterfaces = number + 1;
+    interface->uuid = host->interface->uuid;
+    for (i = 0; i < number; i++)
+       interface->interface[i] = host->interface->interface[i];
+    
+    /* Add the new valid interface */
+    interface->interface[number].addr = addr;
+    interface->interface[number].port = port;
+    interface->interface[number].valid = 1;
+    h_AddHostToAddrHashTable_r(addr, port, host);
+    free(host->interface);
+    host->interface = interface;
+    
     return 0;
 }
 
 
 /*
- * This is called with host locked and held. At this point, the
- * hostHashTable should not be having entries for the alternate
- * interfaces. This function has to insert these entries in the
- * hostHashTable.
+ * This is called with host locked and held.
  *
  * All addresses are in network byte order.
  */
@@ -1060,16 +1282,16 @@ removeInterfaceAddr_r(struct host *host, afs_uint32 addr, afs_uint16 port)
 {
     int i;
     int number;
-    int found;
     struct Interface *interface;
     char hoststr[16], hoststr2[16];
 
     assert(host);
     assert(host->interface);
 
-    ViceLog(125, ("removeInterfaceAddr : host %s:%d addr %s:%d\n", 
-                  afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port), 
-                  afs_inet_ntoa_r(addr, hoststr2), ntohs(port)));
+    ViceLog(125, ("removeInterfaceAddr : host %" AFS_PTR_FMT " (%s:%d) addr %s:%d\n", 
+                 host, afs_inet_ntoa_r(host->host, hoststr), 
+                 ntohs(host->port), afs_inet_ntoa_r(addr, hoststr2), 
+                 ntohs(port)));
 
     /*
      * Make sure this address is on the list of known addresses
@@ -1077,39 +1299,175 @@ removeInterfaceAddr_r(struct host *host, afs_uint32 addr, afs_uint16 port)
      */
     interface = host->interface;
     number = host->interface->numberOfInterfaces;
-    for (i = 0, found = 0; i < number; i++) {
+    for (i = 0; i < number; i++) {
        if (interface->interface[i].addr == addr &&
            interface->interface[i].port == port) {
-           found = 1;
-           break;
-       }
-    }
-    if (found) {
-       number--;
-       for (; i < number; i++) {
-           interface->interface[i].addr = interface->interface[i+1].addr;
-           interface->interface[i].port = interface->interface[i+1].port;
+           if (interface->interface[i].valid)
+               h_DeleteHostFromAddrHashTable_r(addr, port, host);
+           number--;
+           for (; i < number; i++) {
+               interface->interface[i] = interface->interface[i+1];
+           }
+           interface->numberOfInterfaces = number;
+           return 0;
        }
-       interface->numberOfInterfaces = number;
-    }
+    }  
+    /* not found */
+    return 0;
+}
 
+/*
+ * This is called with host locked and held.
+ *
+ * All addresses are in network byte order.
+ */
+int
+invalidateInterfaceAddr_r(struct host *host, afs_uint32 addr, afs_uint16 port)
+{
+    int i;
+    int number;
+    struct Interface *interface;
+    char hoststr[16], hoststr2[16];
+    
+    assert(host);
+    assert(host->interface);
+    
+    ViceLog(125, ("invalidateInterfaceAddr : host %" AFS_PTR_FMT " (%s:%d) addr %s:%d\n", 
+                 host, afs_inet_ntoa_r(host->host, hoststr), 
+                 ntohs(host->port), afs_inet_ntoa_r(addr, hoststr2), 
+                 ntohs(port)));
+    
     /*
-     * Remove the hash table entry for this address
+     * Make sure this address is on the list of known addresses
+     * for this host.
      */
-    h_DeleteHostFromHashTableByAddr_r(addr, port, host);
-
+    interface = host->interface;
+    number = host->interface->numberOfInterfaces;
+    for (i = 0; i < number; i++) {
+       if (interface->interface[i].addr == addr &&
+           interface->interface[i].port == port) {
+            if (interface->interface[i].valid) {
+                h_DeleteHostFromAddrHashTable_r(addr, port, host);
+               interface->interface[i].valid = 0;
+           }
+           return 0;
+       }
+    }
+    
+    /* not found */
     return 0;
 }
 
+/*
+ * This is called with host locked and held.  This function differs
+ * from removeInterfaceAddr_r in that it is called when the address
+ * is being removed from the host regardless of whether or not there
+ * is an interface list for the host.  This function will delete the
+ * host if there are no addresses left on it.
+ *
+ * All addresses are in network byte order.
+ */
+int
+removeAddress_r(struct host *host, afs_uint32 addr, afs_uint16 port)
+{
+    int i;
+    char hoststr[16], hoststr2[16];
+    struct rx_connection *rxconn;
+
+    if (!host->interface || host->interface->numberOfInterfaces == 1) {
+        if (host->host == addr && host->port == port) {
+            ViceLog(25,
+                    ("Removing only address for host %" AFS_PTR_FMT " (%s:%d), deleting host.\n",
+                     host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
+            host->hostFlags |= HOSTDELETED;
+            /* 
+             * Do not remove the primary addr/port from the hash table.
+             * It will be ignored due to the HOSTDELETED flag and will
+             * be removed when h_TossStuff_r() cleans up the HOSTDELETED
+             * host.  Removing it here will only result in a search for 
+             * the host/addr/port in the hash chain which will fail.
+             */
+        } else {
+            ViceLog(0,
+                    ("Removing address that does not belong to host %" AFS_PTR_FMT " (%s:%d).\n",
+                     host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
+        }
+    } else {
+        if (host->host == addr && host->port == port)  {
+            removeInterfaceAddr_r(host, addr, port);
+
+            for (i=0; i < host->interface->numberOfInterfaces; i++) {
+                if (host->interface->interface[i].valid) {
+                    ViceLog(25,
+                             ("Removed address for host %" AFS_PTR_FMT " (%s:%d), new primary interface %s:%d.\n",
+                               host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port),
+                               afs_inet_ntoa_r(host->interface->interface[i].addr, hoststr2), 
+                               ntohs(host->interface->interface[i].port)));
+                    host->host = host->interface->interface[i].addr;
+                    host->port = host->interface->interface[i].port;
+                    h_AddHostToAddrHashTable_r(host->host, host->port, host);
+                    break;
+                }
+            }
+
+            if (i == host->interface->numberOfInterfaces) {
+                ViceLog(25,
+                         ("Removed only address for host %" AFS_PTR_FMT " (%s:%d), no valid alternate interfaces, deleting host.\n",
+                           host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
+                host->hostFlags |= HOSTDELETED;
+                /* addr/port was removed from the hash table */
+                host->host = 0;
+                host->port = 0;
+            } else {
+                rxconn = host->callback_rxcon;
+                host->callback_rxcon = NULL;
+
+                if (rxconn) {
+                    rx_DestroyConnection(rxconn);
+                    rxconn = NULL;
+                }
+
+                if (!sc)
+                    sc = rxnull_NewClientSecurityObject();
+                host->callback_rxcon =
+                    rx_NewConnection(host->host, host->port, 1, sc, 0);
+                rx_SetConnDeadTime(host->callback_rxcon, 50);
+                rx_SetConnHardDeadTime(host->callback_rxcon, AFS_HARDDEADTIME);
+            }
+        } else {
+            /* not the primary addr/port, just invalidate it */
+            invalidateInterfaceAddr_r(host, addr, port);
+        }
+    }
 
-/* Host is returned held */
+    return 0;
+}
+static int
+h_threadquota(int waiting) 
+{
+    if (lwps > 64) {
+       if (waiting > 5)
+           return 1;
+    } else if (lwps > 32) {
+       if (waiting > 4)
+           return 1;
+    } else if (lwps > 16) {
+       if (waiting > 3)
+           return 1;
+    } else {
+       if (waiting > 2)
+           return 1;
+    }
+    return 0;
+}
+
+/* If found, host is returned with refCount incremented */
 struct host *
 h_GetHost_r(struct rx_connection *tcon)
 {
     struct host *host;
     struct host *oldHost;
     int code;
-    int held, oheld;
     struct interfaceAddr interf;
     int interfValid = 0;
     struct Identity *identP = NULL;
@@ -1118,49 +1476,97 @@ h_GetHost_r(struct rx_connection *tcon)
     char hoststr[16], hoststr2[16];
     Capabilities caps;
     struct rx_connection *cb_conn = NULL;
+    struct rx_connection *cb_in = NULL;
 
     caps.Capabilities_val = NULL;
 
     haddr = rxr_HostOf(tcon);
     hport = rxr_PortOf(tcon);
   retry:
+    if (cb_in) {
+        rx_DestroyConnection(cb_in);
+        cb_in = NULL;
+    }
     if (caps.Capabilities_val)
        free(caps.Capabilities_val);
     caps.Capabilities_val = NULL;
     caps.Capabilities_len = 0;
 
     code = 0;
-    host = h_Lookup_r(haddr, hport, &held);
+    if (h_Lookup_r(haddr, hport, &host))
+       return 0;
     identP = (struct Identity *)rx_GetSpecific(tcon, rxcon_ident_key);
     if (host && !identP && !(host->Console & 1)) {
        /* This is a new connection, and we already have a host
         * structure for this address. Verify that the identity
         * of the caller matches the identity in the host structure.
         */
+       if ((host->hostFlags & HWHO_INPROGRESS) && 
+           h_threadquota(host->lock.num_waiting)) {
+               h_Release_r(host);
+           host = NULL;
+           goto gethost_out;
+       }
        h_Lock_r(host);
-       if (!(host->hostFlags & ALTADDR)) {
-           /* Another thread is doing initialization */
+       if (!(host->hostFlags & ALTADDR) ||
+            (host->hostFlags & HOSTDELETED)) {
+           /* Another thread is doing initialization
+             * or this host was deleted while we
+             * waited for the lock. */
            h_Unlock_r(host);
-           if (!held)
-               h_Release_r(host);
            ViceLog(125,
-                   ("Host %s:%d starting h_Lookup again\n",
-                    afs_inet_ntoa_r(host->host, hoststr),
+                   ("Host %" AFS_PTR_FMT " (%s:%d) starting h_Lookup again\n",
+                    host, afs_inet_ntoa_r(host->host, hoststr),
                     ntohs(host->port)));
+           h_Release_r(host);
            goto retry;
        }
+       host->hostFlags |= HWHO_INPROGRESS;
        host->hostFlags &= ~ALTADDR;
+
+        /* We received a new connection from an IP address/port
+         * that is associated with 'host' but the address/port of
+         * the callback connection does not have to match it.
+         * If there is a match, we can use the existing callback
+         * connection to verify the UUID.  If they do not match
+         * we need to use a new callback connection to verify the
+         * UUID of the incoming caller and perhaps use the old 
+         * callback connection to verify that the old address/port
+         * is still valid.
+         */
+       
        cb_conn = host->callback_rxcon;
        rx_GetConnection(cb_conn);
        H_UNLOCK;
-       code =
-           RXAFSCB_TellMeAboutYourself(cb_conn, &interf, &caps);
-       if (code == RXGEN_OPCODE)
-           code = RXAFSCB_WhoAreYou(cb_conn, &interf);
+        if (haddr == host->host && hport == host->port) {
+            /* The existing callback connection matches the 
+             * incoming connection so just use it.
+             */
+           code =
+               RXAFSCB_TellMeAboutYourself(cb_conn, &interf, &caps);
+           if (code == RXGEN_OPCODE)
+               code = RXAFSCB_WhoAreYou(cb_conn, &interf);
+       } else {
+            /* We do not have a match.  Create a new connection
+             * for the new addr/port and use multi_Rx to probe
+             * both of them simultaneously.
+             */
+           if (!sc)
+                sc = rxnull_NewClientSecurityObject();
+            cb_in = rx_NewConnection(haddr, hport, 1, sc, 0);
+            rx_SetConnDeadTime(cb_in, 50);
+            rx_SetConnHardDeadTime(cb_in, AFS_HARDDEADTIME);
+           
+            code =
+                RXAFSCB_TellMeAboutYourself(cb_in, &interf, &caps);
+           if (code == RXGEN_OPCODE)
+                code = RXAFSCB_WhoAreYou(cb_in, &interf);
+       }
        rx_PutConnection(cb_conn);
        cb_conn=NULL;
        H_LOCK;
-       if (code == RXGEN_OPCODE) {
+       if ((code == RXGEN_OPCODE) || 
+           ((code == 0) && (afs_uuid_equal(&interf.uuid, &nulluuid)))) {
            identP = (struct Identity *)malloc(sizeof(struct Identity));
            if (!identP) {
                ViceLog(0, ("Failed malloc in h_GetHost_r\n"));
@@ -1168,21 +1574,38 @@ h_GetHost_r(struct rx_connection *tcon)
            }
            identP->valid = 0;
            rx_SetSpecific(tcon, rxcon_ident_key, identP);
-           /* The host on this connection was unable to respond to 
-            * the WhoAreYou. We will treat this as a new connection
-            * from the existing host. The worst that can happen is
-            * that we maintain some extra callback state information */
-           if (host->interface) {
-               ViceLog(0,
-                       ("Host %s:%d used to support WhoAreYou, deleting.\n",
-                        afs_inet_ntoa_r(host->host, hoststr),
-                        ntohs(host->port)));
-               host->hostFlags |= HOSTDELETED;
-               h_Unlock_r(host);
-               if (!held)
+           if (cb_in == NULL) {
+               /* The host on this connection was unable to respond to 
+                * the WhoAreYou. We will treat this as a new connection
+                * from the existing host. The worst that can happen is
+                * that we maintain some extra callback state information */
+               if (host->interface) {
+                   ViceLog(0,
+                           ("Host %" AFS_PTR_FMT " (%s:%d) used to support WhoAreYou, deleting.\n",
+                            host, 
+                            afs_inet_ntoa_r(host->host, hoststr),
+                            ntohs(host->port)));
+                   host->hostFlags |= HOSTDELETED;
+                   host->hostFlags &= ~HWHO_INPROGRESS;
+                   h_Unlock_r(host);
                    h_Release_r(host);
-               host = NULL;
-               goto retry;
+                   host = NULL;
+                   goto retry;
+               }
+           } else {
+               /* The incoming connection does not support WhoAreYou but
+                * the original one might have.  Use removeAddress_r() to
+                 * remove this addr/port from the host that was found.
+                 * If there are no more addresses left for the host it 
+                 * will be deleted.  Then we retry.
+                 */
+                removeAddress_r(host, haddr, hport);
+                host->hostFlags &= ~HWHO_INPROGRESS;
+                host->hostFlags |= ALTADDR;
+                h_Unlock_r(host);
+               h_Release_r(host);
+                host = NULL;
+                goto retry;
            }
        } else if (code == 0) {
            interfValid = 1;
@@ -1199,22 +1622,105 @@ h_GetHost_r(struct rx_connection *tcon)
             * then this is not the same host as before. */
            if (!host->interface
                || !afs_uuid_equal(&interf.uuid, &host->interface->uuid)) {
-               ViceLog(25,
-                       ("Host %s:%d has changed its identity, deleting.\n",
-                        afs_inet_ntoa_r(host->host, hoststr), host->port));
-               host->hostFlags |= HOSTDELETED;
+               if (cb_in) {
+                       ViceLog(25,
+                                       ("Uuid doesn't match connection (%s:%d).\n",
+                                        afs_inet_ntoa_r(haddr, hoststr), ntohs(hport)));
+                       removeAddress_r(host, haddr, hport);
+               } else {
+                   ViceLog(25,
+                           ("Uuid doesn't match host %" AFS_PTR_FMT " (%s:%d).\n",
+                            host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
+                   
+                   removeAddress_r(host, host->host, host->port);
+               }
+               host->hostFlags &= ~HWHO_INPROGRESS;
+                host->hostFlags |= ALTADDR;
                h_Unlock_r(host);
-               if (!held)
-                   h_Release_r(host);
+               h_Release_r(host);
                host = NULL;
                goto retry;
+           } else if (cb_in) {
+               /* the UUID matched the client at the incoming addr/port 
+                 * but this is not the address of the active callback 
+                 * connection.  Try that connection and see if the client
+                 * is still there and if the reported UUID is the same.
+                 */
+                int code2;
+                afsUUID uuid = host->interface->uuid;
+                cb_conn = host->callback_rxcon;
+                rx_GetConnection(cb_conn);
+                rx_SetConnDeadTime(cb_conn, 2);
+                rx_SetConnHardDeadTime(cb_conn, AFS_HARDDEADTIME);
+                H_UNLOCK;
+                code2 = RXAFSCB_ProbeUuid(cb_conn, &uuid);
+                H_LOCK;
+                rx_SetConnDeadTime(cb_conn, 50);
+                rx_SetConnHardDeadTime(cb_conn, AFS_HARDDEADTIME);
+                rx_PutConnection(cb_conn);
+                cb_conn=NULL;
+                if (code2) {
+                    /* The primary address is either not responding or
+                     * is not the client we are looking for.  Need to
+                     * remove the primary address and add swap in the new 
+                     * callback connection, and destroy the old one.
+                     */
+                    struct rx_connection *rxconn;
+                    ViceLog(0,("CB: ProbeUuid for host %" AFS_PTR_FMT " (%s:%d) failed %d\n",
+                              host, 
+                              afs_inet_ntoa_r(host->host, hoststr),
+                              ntohs(host->port),code2));
+
+                    /* 
+                     * make sure we add and then remove.  otherwise, we
+                     * might end up with no valid interfaces after the 
+                     * remove and the host will have been marked deleted.
+                     */
+                    addInterfaceAddr_r(host, haddr, hport);
+                    removeInterfaceAddr_r(host, host->host, host->port);
+                    host->host = haddr;
+                    host->port = hport;
+                    rxconn = host->callback_rxcon;
+                    host->callback_rxcon = cb_in;
+                    cb_in = NULL;
+                   
+                    if (rxconn) {
+                        /*
+                         * If rx_DestroyConnection calls h_FreeConnection we
+                        * will deadlock on the host_glock_mutex. Work around
+                        * the problem by unhooking the client from the
+                        * connection before destroying the connection.
+                         */
+                        rx_SetSpecific(rxconn, rxcon_client_key, (void *)0);
+                        rx_DestroyConnection(rxconn);
+                   }
+               }
            }
        } else {
-           afs_inet_ntoa_r(host->host, hoststr);
-           ViceLog(0,
-                   ("CB: WhoAreYou failed for %s:%d, error %d\n", hoststr,
-                    ntohs(host->port), code));
-           host->hostFlags |= VENUSDOWN;
+            if (cb_in) {
+                /* A callback to the incoming connection address is failing.  
+                 * Assume that the addr/port is no longer associated with the host
+                 * returned by h_Lookup_r.
+                 */
+                ViceLog(0,
+                       ("CB: WhoAreYou failed for connection (%s:%d) , error %d\n",
+                        afs_inet_ntoa_r(haddr, hoststr), ntohs(hport), code));
+                removeAddress_r(host, haddr, hport);
+                host->hostFlags &= ~HWHO_INPROGRESS;
+                host->hostFlags |= ALTADDR;
+                h_Unlock_r(host);
+               h_Release_r(host);
+                host = NULL;
+                rx_DestroyConnection(cb_in);
+               cb_in = NULL;
+               goto gethost_out;
+           } else {
+               ViceLog(0,
+                       ("CB: WhoAreYou failed for host %" AFS_PTR_FMT " (%s:%d), error %d\n",
+                        host, afs_inet_ntoa_r(host->host, hoststr),
+                        ntohs(host->port), code));
+               host->hostFlags |= VENUSDOWN;
+           }
        }
        if (caps.Capabilities_val
            && (caps.Capabilities_val[0] & CLIENT_CAPABILITY_ERRORTRANS))
@@ -1222,22 +1728,22 @@ h_GetHost_r(struct rx_connection *tcon)
        else
            host->hostFlags &= ~(HERRORTRANS);
        host->hostFlags |= ALTADDR;
+       host->hostFlags &= ~HWHO_INPROGRESS;
        h_Unlock_r(host);
     } else if (host) {
        if (!(host->hostFlags & ALTADDR)) {
            /* another thread is doing the initialisation */
            ViceLog(125,
-                   ("Host %s:%d waiting for host-init to complete\n",
-                    afs_inet_ntoa_r(host->host, hoststr),
+                   ("Host %" AFS_PTR_FMT " (%s:%d) waiting for host-init to complete\n",
+                    host, afs_inet_ntoa_r(host->host, hoststr),
                     ntohs(host->port)));
            h_Lock_r(host);
            h_Unlock_r(host);
-           if (!held)
-               h_Release_r(host);
            ViceLog(125,
-                   ("Host %s:%d starting h_Lookup again\n",
-                    afs_inet_ntoa_r(host->host, hoststr),
+                   ("Host %" AFS_PTR_FMT " (%s:%d) starting h_Lookup again\n",
+                    host, afs_inet_ntoa_r(host->host, hoststr),
                     ntohs(host->port)));
+           h_Release_r(host);
            goto retry;
        }
        /* We need to check whether the identity in the host structure
@@ -1255,17 +1761,17 @@ h_GetHost_r(struct rx_connection *tcon)
            if (host->interface)
                afsUUID_to_string(&host->interface->uuid, uuid2, 127);
            ViceLog(0,
-                   ("CB: new identity for host %s:%d, deleting(%x %x %s %s)\n",
-                    afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port),
+                   ("CB: new identity for host %" AFS_PTR_FMT " (%s:%d), deleting(%x %x %s %s)\n",
+                    host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port),
                     identP->valid, host->interface,
-                    identP->valid ? uuid1 : "",
-                    host->interface ? uuid2 : ""));
+                    identP->valid ? uuid1 : "no_uuid",
+                    host->interface ? uuid2 : "no_uuid"));
 
            /* The host in the cache is not the host for this connection */
+            h_Lock_r(host);
            host->hostFlags |= HOSTDELETED;
            h_Unlock_r(host);
-           if (!held)
-               h_Release_r(host);
+           h_Release_r(host);
            goto retry;
        }
     } else {
@@ -1275,6 +1781,7 @@ h_GetHost_r(struct rx_connection *tcon)
            int pident = 0;
            cb_conn = host->callback_rxcon;
            rx_GetConnection(cb_conn);
+           host->hostFlags |= HWHO_INPROGRESS;
            H_UNLOCK;
            code =
                RXAFSCB_TellMeAboutYourself(cb_conn, &interf, &caps);
@@ -1283,7 +1790,8 @@ h_GetHost_r(struct rx_connection *tcon)
            rx_PutConnection(cb_conn);
            cb_conn=NULL;
            H_LOCK;
-           if (code == RXGEN_OPCODE) {
+           if ((code == RXGEN_OPCODE) || 
+               ((code == 0) && (afs_uuid_equal(&interf.uuid, &nulluuid)))) {
                if (!identP)
                    identP =
                        (struct Identity *)malloc(sizeof(struct Identity));
@@ -1298,8 +1806,8 @@ h_GetHost_r(struct rx_connection *tcon)
                if (!pident)
                    rx_SetSpecific(tcon, rxcon_ident_key, identP);
                ViceLog(25,
-                       ("Host %s:%d does not support WhoAreYou.\n",
-                        afs_inet_ntoa_r(host->host, hoststr),
+                       ("Host %" AFS_PTR_FMT " (%s:%d) does not support WhoAreYou.\n",
+                        host, afs_inet_ntoa_r(host->host, hoststr),
                         ntohs(host->port)));
                code = 0;
            } else if (code == 0) {
@@ -1319,8 +1827,8 @@ h_GetHost_r(struct rx_connection *tcon)
                if (!pident)
                    rx_SetSpecific(tcon, rxcon_ident_key, identP);
                ViceLog(25,
-                       ("WhoAreYou success on %s:%d\n",
-                        afs_inet_ntoa_r(host->host, hoststr),
+                       ("WhoAreYou success on host %" AFS_PTR_FMT " (%s:%d)\n",
+                        host, afs_inet_ntoa_r(host->host, hoststr),
                         ntohs(host->port)));
            }
            if (code == 0 && !identP->valid) {
@@ -1334,83 +1842,113 @@ h_GetHost_r(struct rx_connection *tcon)
            } else if (code == 0) {
                oldHost = h_LookupUuid_r(&identP->uuid);
                 if (oldHost) {
-                    int probefail = 0;
-
-                   if (!(oheld = h_Held_r(oldHost)))
-                       h_Hold_r(oldHost);
+                   h_Hold_r(oldHost);
                    h_Lock_r(oldHost);
 
+                   if (oldHost->hostFlags & HOSTDELETED) {
+                       h_Unlock_r(oldHost);
+                       h_Release_r(oldHost);
+                       oldHost = NULL;
+                   }
+               }
+
+               if (oldHost) {
+                   int probefail = 0;
+
+                   oldHost->hostFlags |= HWHO_INPROGRESS;
+
                     if (oldHost->interface) {
+                       int code2;
                        afsUUID uuid = oldHost->interface->uuid;
                         cb_conn = oldHost->callback_rxcon;
                         rx_GetConnection(cb_conn);
                        rx_SetConnDeadTime(cb_conn, 2);
                        rx_SetConnHardDeadTime(cb_conn, AFS_HARDDEADTIME);
                        H_UNLOCK;
-                       code = RXAFSCB_ProbeUuid(cb_conn, &uuid);
+                       code2 = RXAFSCB_ProbeUuid(cb_conn, &uuid);
                        H_LOCK;
                        rx_SetConnDeadTime(cb_conn, 50);
                        rx_SetConnHardDeadTime(cb_conn, AFS_HARDDEADTIME);
                         rx_PutConnection(cb_conn);
                         cb_conn=NULL;
-                       if (code && MultiProbeAlternateAddress_r(oldHost)) {
+                       if (code2) {
+                           /* The primary address is either not responding or
+                            * is not the client we are looking for.  
+                            * MultiProbeAlternateAddress_r() will remove the
+                            * alternate interfaces that do not have the same
+                            * Uuid. */
+                           ViceLog(0,("CB: ProbeUuid for host %" AFS_PTR_FMT " (%s:%d) failed %d\n",
+                                        oldHost, 
+                                         afs_inet_ntoa_r(oldHost->host, hoststr),
+                                        ntohs(oldHost->port),code2));
+                           MultiProbeAlternateAddress_r(oldHost);
                             probefail = 1;
                         }
                     } else {
                         probefail = 1;
                     }
 
-                    if (probefail) {
-                        /* The old host is either does not have a Uuid,
-                         * is not responding to Probes, 
-                         * or does not have a matching Uuid. 
-                         * Delete it! */
-                        oldHost->hostFlags |= HOSTDELETED;
-                        h_Unlock_r(oldHost);
-                       /* Let the holder be last release */
-                       if (!oheld) {
-                           h_Release_r(oldHost);
-                       }
-                       oldHost = NULL;
-                    }
-                }
-               if (oldHost) {
                    /* This is a new address for an existing host. Update
                     * the list of interfaces for the existing host and
                     * delete the host structure we just allocated. */
+
+                    /* prevent warnings while manipulating interface lists */
+                   host->hostFlags |= HOSTDELETED;
+
                    if (oldHost->host != haddr || oldHost->port != hport) {
+                       struct rx_connection *rxconn;
+
                        ViceLog(25,
-                               ("CB: new addr %s:%d for old host %s:%d\n",
-                                 afs_inet_ntoa_r(haddr, hoststr),
-                                 ntohs(hport), 
-                                 afs_inet_ntoa_r(oldHost->host, hoststr2),
-                                 ntohs(oldHost->port)));
-                       if (oldHost->host == haddr) {
-                           /* We have just been contacted by a client behind a NAT */
+                                 ("CB: Host %" AFS_PTR_FMT " (%s:%d) has new addr %s:%d\n",
+                                   oldHost, 
+                                   afs_inet_ntoa_r(oldHost->host, hoststr2),
+                                   ntohs(oldHost->port),
+                                   afs_inet_ntoa_r(haddr, hoststr),
+                                   ntohs(hport)));
+                       /* 
+                        * add then remove.  otherwise the host may get marked
+                        * deleted if we removed the only valid address.
+                        */
+                       addInterfaceAddr_r(oldHost, haddr, hport);
+                       if (probefail || oldHost->host == haddr) {
+                           /* 
+                            * The probe failed which means that the old 
+                            * address is either unreachable or is not the 
+                            * same host we were just contacted by.  We will 
+                            * also remove addresses if only the port has 
+                            * changed because that indicates the client
+                            * is behind a NAT. 
+                            */
                            removeInterfaceAddr_r(oldHost, oldHost->host, oldHost->port);
                        } else {
-                           int i, found;
+                           int i;
                            struct Interface *interface = oldHost->interface;
                            int number = oldHost->interface->numberOfInterfaces;
-                           for (i = 0, found = 0; i < number; i++) {
+                           for (i = 0; i < number; i++) {
                                if (interface->interface[i].addr == haddr &&
                                    interface->interface[i].port != hport) {
-                                   found = 1;
+                                   /* 
+                                    * We have just been contacted by a client
+                                    * that has been seen from behind a NAT 
+                                    * and at least one other address.
+                                    */
+                                   removeInterfaceAddr_r(oldHost, haddr, 
+                                                         interface->interface[i].port);
                                    break;
                                }
                            }
-                           if (found) {
-                               /* We have just been contacted by a client that has been
-                                * seen from behind a NAT and at least one other address.
-                                */
-                               removeInterfaceAddr_r(oldHost, haddr, interface->interface[i].port);
-                           }
                        }
-                       addInterfaceAddr_r(oldHost, haddr, hport);
+                       h_AddHostToAddrHashTable_r(haddr, hport, oldHost);
                        oldHost->host = haddr;
                        oldHost->port = hport;
+                       rxconn = oldHost->callback_rxcon;
+                       oldHost->callback_rxcon = host->callback_rxcon;
+                       host->callback_rxcon = rxconn;
+                       
+                        /* don't destroy rxconn here; let h_TossStuff_r
+                         * take care of that via h_Release_r below */
                    }
-                   host->hostFlags |= HOSTDELETED;
+                   host->hostFlags &= ~HWHO_INPROGRESS;
                    h_Unlock_r(host);
                    /* release host because it was allocated by h_Alloc_r */
                    h_Release_r(host);
@@ -1430,8 +1968,8 @@ h_GetHost_r(struct rx_connection *tcon)
                    H_LOCK;
                    if (code == 0) {
                        ViceLog(25,
-                               ("InitCallBackState3 success on %s:%d\n",
-                                afs_inet_ntoa_r(host->host, hoststr),
+                               ("InitCallBackState3 success on host %" AFS_PTR_FMT " (%s:%d)\n",
+                                host, afs_inet_ntoa_r(host->host, hoststr),
                                 ntohs(host->port)));
                        assert(interfValid == 1);
                        initInterfaceAddr_r(host, &interf);
@@ -1439,15 +1977,14 @@ h_GetHost_r(struct rx_connection *tcon)
                }
            }
            if (code) {
-               afs_inet_ntoa_r(host->host, hoststr);
                ViceLog(0,
-                       ("CB: RCallBackConnectBack failed for %s:%d\n",
-                        hoststr, ntohs(host->port)));
+                       ("CB: RCallBackConnectBack failed for %" AFS_PTR_FMT " (%s:%d)\n",
+                        host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
                host->hostFlags |= VENUSDOWN;
            } else {
                ViceLog(125,
-                       ("CB: RCallBackConnectBack succeeded for %s:%d\n",
-                        hoststr, ntohs(host->port)));
+                       ("CB: RCallBackConnectBack succeeded for %" AFS_PTR_FMT " (%s:%d)\n",
+                        host, afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
                host->hostFlags |= RESETDONE;
            }
        }
@@ -1457,12 +1994,19 @@ h_GetHost_r(struct rx_connection *tcon)
        else
            host->hostFlags &= ~(HERRORTRANS);
        host->hostFlags |= ALTADDR;     /* host structure initialization complete */
+       host->hostFlags &= ~HWHO_INPROGRESS;
        h_Unlock_r(host);
     }
+
+ gethost_out:
     if (caps.Capabilities_val)
        free(caps.Capabilities_val);
     caps.Capabilities_val = NULL;
     caps.Capabilities_len = 0;
+    if (cb_in) {
+        rx_DestroyConnection(cb_in);
+        cb_in = NULL;
+    }
     return host;
 
 }                              /*h_GetHost_r */
@@ -1474,8 +2018,9 @@ int  num_lrealms = -1;
 
 /* not reentrant */
 void
-h_InitHostPackage()
+h_InitHostPackage(void)
 {
+    memset(&nulluuid, 0, sizeof(afsUUID));
     afsconf_GetLocalCell(confDir, localcellname, PR_MAXNAMELEN);
     if (num_lrealms == -1) {
        int i;
@@ -1484,7 +2029,7 @@ h_InitHostPackage()
                break;
        }
 
-       if (i=0) {
+       if (i == 0) {
            ViceLog(0,
                    ("afs_krb_get_lrealm failed, using %s.\n",
                     localcellname));
@@ -1551,7 +2096,7 @@ MapName_r(char *aname, char *acell, afs_int32 * aval)
     }
 
     H_UNLOCK;
-    code = pr_NameToId(&lnames, &lids);
+    code = hpr_NameToId(&lnames, &lids);
     H_LOCK;
     if (code == 0) {
        if (lids.idlist_val) {
@@ -1585,9 +2130,10 @@ h_ID2Client(afs_int32 vid)
 {
     register struct client *client;
     register struct host *host;
+    int count;
 
     H_LOCK;
-    for (host = hostList; host; host = host->next) {
+    for (count = 0, host = hostList; host && count < hostCount; host = host->next, count++) {
        if (host->hostFlags & HOSTDELETED)
            continue;
        for (client = host->FirstClient; client; client = client->next) {
@@ -1599,6 +2145,12 @@ h_ID2Client(afs_int32 vid)
            }
        }
     }
+    if (count != hostCount) {
+       ViceLog(0, ("h_ID2Client found %d of %d hosts\n", count, hostCount));
+    } else if (host != NULL) {
+       ViceLog(0, ("h_ID2Client found more than %d hosts\n", hostCount));
+       ShutDownAndCore(PANIC);
+    }
 
     H_UNLOCK;
     return NULL;
@@ -1611,16 +2163,16 @@ h_ID2Client(afs_int32 vid)
  * by one. The caller must call h_ReleaseClient_r when finished with
  * the client.
  *
- * the client->host is returned held.  h_ReleaseClient_r does not release
- * the hold on client->host.
+ * The refCount on client->host is returned incremented.  h_ReleaseClient_r
+ * does not decrement the refCount on client->host.
  */
 struct client *
 h_FindClient_r(struct rx_connection *tcon)
 {
     register struct client *client;
-    register struct host *host;
+    struct host *host = NULL;
     struct client *oldClient;
-    afs_int32 viceid;
+    afs_int32 viceid = 0;
     afs_int32 expTime;
     afs_int32 code;
     int authClass;
@@ -1635,7 +2187,8 @@ h_FindClient_r(struct rx_connection *tcon)
     int created = 0;
 
     client = (struct client *)rx_GetSpecific(tcon, rxcon_client_key);
-    if (client) {
+    if (client && client->sid == rxr_CidOf(tcon) 
+       && client->VenusEpoch == rxr_GetEpoch(tcon)) {
        client->refCount++;
        h_Hold_r(client->host);
        if (!client->deleted && client->prfail != 2) {  
@@ -1650,6 +2203,8 @@ h_FindClient_r(struct rx_connection *tcon)
        H_UNLOCK;
        ObtainWriteLock(&client->lock); /* released at end */
        H_LOCK;
+    } else {
+       client = NULL;
     }
 
     authClass = rx_SecurityClassOf((struct rx_connection *)tcon);
@@ -1663,9 +2218,9 @@ h_FindClient_r(struct rx_connection *tcon)
        expTime = 0x7fffffff;
     } else if (authClass == 2) {
        afs_int32 kvno;
-
+    
        /* kerberos ticket */
-       code = rxkad_GetServerInfo(tcon, /*level */ 0, &expTime,
+       code = rxkad_GetServerInfo(tcon, /*level */ 0, (afs_uint32 *)&expTime,
                                   tname, tinst, tcell, &kvno);
        if (code) {
            ViceLog(1, ("Failed to get rxkad ticket info\n"));
@@ -1701,32 +2256,16 @@ h_FindClient_r(struct rx_connection *tcon)
     }
 
     if (!client) { /* loop */
-       host = h_GetHost_r(tcon);       /* Returns it h_Held */
+       host = h_GetHost_r(tcon);       /* Returns with incremented refCount  */
+
+       if (!host) 
+           return NULL;
 
     retryfirstclient:
        /* First try to find the client structure */
        for (client = host->FirstClient; client; client = client->next) {
            if (!client->deleted && (client->sid == rxr_CidOf(tcon))
                && (client->VenusEpoch == rxr_GetEpoch(tcon))) {
-               if (client->tcon && (client->tcon != tcon)) {
-                   ViceLog(0,
-                           ("*** Vid=%d, sid=%x, tcon=%x, Tcon=%x ***\n",
-                            client->ViceId, client->sid, client->tcon,
-                            tcon));
-                   oldClient =
-                       (struct client *)rx_GetSpecific(client->tcon,
-                                                       rxcon_client_key);
-                   if (oldClient) {
-                       if (oldClient == client)
-                           rx_SetSpecific(client->tcon, rxcon_client_key,
-                                          NULL);
-                       else
-                           ViceLog(0,
-                                   ("Client-conn mismatch: CL1=%x, CN=%x, CL2=%x\n",
-                                    client, client->tcon, oldClient));
-                   }
-                   client->tcon = (struct rx_connection *)0;
-               }
                client->refCount++;
                H_UNLOCK;
                ObtainWriteLock(&client->lock);
@@ -1738,6 +2277,11 @@ h_FindClient_r(struct rx_connection *tcon)
        /* Still no client structure - get one */
        if (!client) {
            h_Lock_r(host);
+            if (host->hostFlags & HOSTDELETED) {
+                h_Unlock_r(host);
+                h_Release_r(host);
+                return NULL;
+            }
            /* Retry to find the client structure */
            for (client = host->FirstClient; client; client = client->next) {
                if (!client->deleted && (client->sid == rxr_CidOf(tcon))
@@ -1779,14 +2323,14 @@ h_FindClient_r(struct rx_connection *tcon)
            client->CPS.prlist_val = AnonCPS.prlist_val;
        } else {
            H_UNLOCK;
-           code = pr_GetCPS(viceid, &client->CPS);
+           code = hpr_GetCPS(viceid, &client->CPS);
            H_LOCK;
            if (code) {
                char hoststr[16];
                ViceLog(0,
-                       ("pr_GetCPS failed(%d) for user %d, host %s:%d\n",
-                        code, viceid, afs_inet_ntoa_r(client->host->host,
-                                                      hoststr),
+                       ("pr_GetCPS failed(%d) for user %d, host %" AFS_PTR_FMT " (%s:%d)\n",
+                        code, viceid, client->host, 
+                         afs_inet_ntoa_r(client->host->host,hoststr),
                         ntohs(client->host->port)));
 
                /* Although ubik_Call (called by pr_GetCPS) traverses thru
@@ -1819,7 +2363,8 @@ h_FindClient_r(struct rx_connection *tcon)
      * the RPC from the other client structure's rock.
      */
     oldClient = (struct client *)rx_GetSpecific(tcon, rxcon_client_key);
-    if (oldClient && oldClient->tcon == tcon) {
+    if (oldClient && oldClient != client && oldClient->sid == rxr_CidOf(tcon)
+       && oldClient->VenusEpoch == rxr_GetEpoch(tcon)) {
        char hoststr[16];
        if (!oldClient->deleted) {
            /* if we didn't create it, it's not ours to put back */
@@ -1833,9 +2378,6 @@ h_FindClient_r(struct rx_connection *tcon)
                    free(client->CPS.prlist_val);
                client->CPS.prlist_val = NULL;
                client->CPS.prlist_len = 0;
-               if (client->tcon) {
-                   rx_SetSpecific(client->tcon, rxcon_client_key, (void *)0);
-               }
            }
            /* We should perhaps check for 0 here */
            client->refCount--;
@@ -1844,11 +2386,12 @@ h_FindClient_r(struct rx_connection *tcon)
                FreeCE(client);
                created = 0;
            } 
-           ObtainWriteLock(&oldClient->lock);
            oldClient->refCount++;
+           H_UNLOCK;
+           ObtainWriteLock(&oldClient->lock);
+           H_LOCK;
            client = oldClient;
        } else {
-           oldClient->tcon = (struct rx_connection *)0;
            ViceLog(0, ("FindClient: deleted client %x(%x) already had conn %x (host %s:%d), stolen by client %x(%x)\n", 
                        oldClient, oldClient->sid, tcon, 
                        afs_inet_ntoa_r(rxr_HostOf(tcon), hoststr),
@@ -1860,12 +2403,30 @@ h_FindClient_r(struct rx_connection *tcon)
     /* Avoid chaining in more than once. */
     if (created) {
        h_Lock_r(host);
+
+        if (host->hostFlags & HOSTDELETED) {
+            h_Unlock_r(host);
+            h_Release_r(host);
+
+            host = NULL;
+            client->host = NULL;
+
+            if ((client->ViceId != ANONYMOUSID) && client->CPS.prlist_val)
+                free(client->CPS.prlist_val);
+            client->CPS.prlist_val = NULL;
+            client->CPS.prlist_len = 0;
+
+            client->refCount--;
+            ReleaseWriteLock(&client->lock);
+            FreeCE(client);
+            return NULL;
+        }
+
        client->next = host->FirstClient;
        host->FirstClient = client;
        h_Unlock_r(host);
        CurrentConnections++;   /* increment number of connections */
     }
-    client->tcon = tcon;
     rx_SetSpecific(tcon, rxcon_client_key, client);
     ReleaseWriteLock(&client->lock);
 
@@ -1893,36 +2454,27 @@ int
 GetClient(struct rx_connection *tcon, struct client **cp)
 {
     register struct client *client;
+    char hoststr[16];
 
     H_LOCK;
     *cp = NULL;
     client = (struct client *)rx_GetSpecific(tcon, rxcon_client_key);
-    if (client == NULL || client->tcon == NULL) {
+    if (client == NULL) {
        ViceLog(0,
-               ("GetClient: no client in conn %x (host %x:%d), VBUSYING\n",
-                tcon, rxr_HostOf(tcon),ntohs(rxr_PortOf(tcon))));
+               ("GetClient: no client in conn %x (host %s:%d), VBUSYING\n",
+                tcon, afs_inet_ntoa_r(rxr_HostOf(tcon), hoststr),
+                 ntohs(rxr_PortOf(tcon))));
        H_UNLOCK;
        return VBUSY;
     }
-    if (rxr_CidOf(client->tcon) != client->sid) {
+    if (rxr_CidOf(tcon) != client->sid || rxr_GetEpoch(tcon) != client->VenusEpoch) {
        ViceLog(0,
                ("GetClient: tcon %x tcon sid %d client sid %d\n",
-                client->tcon, rxr_CidOf(client->tcon), client->sid));
+                tcon, rxr_CidOf(tcon), client->sid));
        H_UNLOCK;
        return VBUSY;
     }
-    if (!(client && client->tcon && rxr_CidOf(client->tcon) == client->sid)) {
-       if (!client)
-           ViceLog(0, ("GetClient: no client in conn %x\n", tcon));
-       else
-           ViceLog(0,
-                   ("GetClient: tcon %x tcon sid %d client sid %d\n",
-                    client->tcon, client->tcon ? rxr_CidOf(client->tcon)
-                    : -1, client->sid));
-       assert(0);
-    }
     if (client && client->LastCall > client->expTime && client->expTime) {
-       char hoststr[16];
        ViceLog(1,
                ("Token for %s at %s:%d expired %d\n", h_UserName(client),
                 afs_inet_ntoa_r(client->host->host, hoststr),
@@ -1968,7 +2520,7 @@ h_UserName(struct client *client)
     lnames.namelist_len = 0;
     lnames.namelist_val = (prname *) 0;
     lids.idlist_val[0] = client->ViceId;
-    if (pr_IdToName(&lids, &lnames)) {
+    if (hpr_IdToName(&lids, &lnames)) {
        /* We need to free id we alloced above! */
        free(lids.idlist_val);
        return "*UNKNOWN USER NAME*";
@@ -1977,12 +2529,11 @@ h_UserName(struct client *client)
     free(lids.idlist_val);
     free(lnames.namelist_val);
     return User;
-
 }                              /*h_UserName */
 
 
 void
-h_PrintStats()
+h_PrintStats(void)
 {
     ViceLog(0,
            ("Total Client entries = %d, blocks = %d; Host entries = %d, blocks = %d\n",
@@ -1992,29 +2543,32 @@ h_PrintStats()
 
 
 static int
-h_PrintClient(register struct host *host, int held, StreamHandle_t * file)
+h_PrintClient(register struct host *host, int flags, void *rock)
 {
+    StreamHandle_t *file = (StreamHandle_t *)rock;
     register struct client *client;
     int i;
     char tmpStr[256];
     char tbuffer[32];
     char hoststr[16];
+    time_t LastCall, expTime;
 
     H_LOCK;
+    LastCall = host->LastCall;
     if (host->hostFlags & HOSTDELETED) {
        H_UNLOCK;
-       return held;
+       return flags;
     }
     (void)afs_snprintf(tmpStr, sizeof tmpStr,
                       "Host %s:%d down = %d, LastCall %s",
                       afs_inet_ntoa_r(host->host, hoststr),
                       ntohs(host->port), (host->hostFlags & VENUSDOWN),
-                      afs_ctime((time_t *) & host->LastCall, tbuffer,
+                      afs_ctime(&LastCall, tbuffer,
                                 sizeof(tbuffer)));
     (void)STREAM_WRITE(tmpStr, strlen(tmpStr), 1, file);
     for (client = host->FirstClient; client; client = client->next) {
        if (!client->deleted) {
-           if (client->tcon) {
+               expTime = client->expTime;
                (void)afs_snprintf(tmpStr, sizeof tmpStr,
                                   "    user id=%d,  name=%s, sl=%s till %s",
                                   client->ViceId, h_UserName(client),
@@ -2022,17 +2576,10 @@ h_PrintClient(register struct host *host, int held, StreamHandle_t * file)
                                   authClass ? "Authenticated" :
                                   "Not authenticated",
                                   client->
-                                  authClass ? afs_ctime((time_t *) & client->
-                                                        expTime, tbuffer,
+                                  authClass ? afs_ctime(&expTime, tbuffer,
                                                         sizeof(tbuffer))
                                   : "No Limit\n");
                (void)STREAM_WRITE(tmpStr, strlen(tmpStr), 1, file);
-           } else {
-               (void)afs_snprintf(tmpStr, sizeof tmpStr,
-                                  "    user=%s, no current server connection\n",
-                                  h_UserName(client));
-               (void)STREAM_WRITE(tmpStr, strlen(tmpStr), 1, file);
-           }
            (void)afs_snprintf(tmpStr, sizeof tmpStr, "      CPS-%d is [",
                               client->CPS.prlist_len);
            (void)STREAM_WRITE(tmpStr, strlen(tmpStr), 1, file);
@@ -2048,7 +2595,7 @@ h_PrintClient(register struct host *host, int held, StreamHandle_t * file)
        }
     }
     H_UNLOCK;
-    return held;
+    return flags;
 
 }                              /*h_PrintClient */
 
@@ -2059,7 +2606,7 @@ h_PrintClient(register struct host *host, int held, StreamHandle_t * file)
  * if known
  */
 void
-h_PrintClients()
+h_PrintClients(void)
 {
     time_t now;
     char tmpStr[256];
@@ -2086,8 +2633,10 @@ h_PrintClients()
 
 
 static int
-h_DumpHost(register struct host *host, int held, StreamHandle_t * file)
+h_DumpHost(register struct host *host, int flags, void *rock)
 {
+    StreamHandle_t *file = (StreamHandle_t *)rock;
+    
     int i;
     char tmpStr[256];
     char hoststr[16];
@@ -2118,24 +2667,17 @@ h_DumpHost(register struct host *host, int held, StreamHandle_t * file)
                     ntohs(host->interface->interface[i].port));
            (void)STREAM_WRITE(tmpStr, strlen(tmpStr), 1, file);
        }
-    sprintf(tmpStr, "] holds: ");
-    (void)STREAM_WRITE(tmpStr, strlen(tmpStr), 1, file);
-
-    for (i = 0; i < h_maxSlots; i++) {
-       sprintf(tmpStr, "%04x", host->holds[i]);
-       (void)STREAM_WRITE(tmpStr, strlen(tmpStr), 1, file);
-    }
-    sprintf(tmpStr, " slot/bit: %d/%d\n", h_holdSlot(), h_holdbit());
+    sprintf(tmpStr, "] refCount: %d\n", host->refCount);
     (void)STREAM_WRITE(tmpStr, strlen(tmpStr), 1, file);
 
     H_UNLOCK;
-    return held;
+    return flags;
 
 }                              /*h_DumpHost */
 
 
 void
-h_DumpHosts()
+h_DumpHosts(void)
 {
     time_t now;
     StreamHandle_t *file = STREAM_OPEN(AFSDIR_SERVER_HOSTDUMP_FILEPATH, "w");
@@ -2166,10 +2708,10 @@ h_DumpHosts()
 static int h_stateFillHeader(struct host_state_header * hdr);
 static int h_stateCheckHeader(struct host_state_header * hdr);
 static int h_stateAllocMap(struct fs_dump_state * state);
-static int h_stateSaveHost(register struct host * host, int held, struct fs_dump_state * state);
+static int h_stateSaveHost(struct host * host, int flags, void *rock);
 static int h_stateRestoreHost(struct fs_dump_state * state);
-static int h_stateRestoreIndex(struct host * h, int held, struct fs_dump_state * state);
-static int h_stateVerifyHost(struct host * h, int held, struct fs_dump_state * state);
+static int h_stateRestoreIndex(struct host * h, int flags, void *rock);
+static int h_stateVerifyHost(struct host * h, int flags, void *rock);
 static int h_stateVerifyAddrHash(struct fs_dump_state * state, struct host * h, afs_uint32 addr, afs_uint16 port);
 static int h_stateVerifyUuidHash(struct fs_dump_state * state, struct host * h);
 static void h_hostToDiskEntry_r(struct host * in, struct hostDiskEntry * out);
@@ -2261,12 +2803,13 @@ h_stateRestoreIndices(struct fs_dump_state * state)
 }
 
 static int
-h_stateRestoreIndex(struct host * h, int held, struct fs_dump_state * state)
+h_stateRestoreIndex(struct host * h, int flags, void *rock)
 {
+    struct fs_dump_state *state = (struct fs_dump_state *)rock;
     if (cb_OldToNew(state, h->cblist, &h->cblist)) {
-       return H_ENUMERATE_BAIL(held);
+       return H_ENUMERATE_BAIL(flags);
     }
-    return held;
+    return flags;
 }
 
 int
@@ -2277,13 +2820,14 @@ h_stateVerify(struct fs_dump_state * state)
 }
 
 static int
-h_stateVerifyHost(struct host * h, int held, struct fs_dump_state * state)
+h_stateVerifyHost(struct host * h, int flags, void* rock)
 {
+    struct fs_dump_state *state = (struct fs_dump_state *)rock;
     int i;
 
     if (h == NULL) {
        ViceLog(0, ("h_stateVerifyHost: error: NULL host pointer in linked list\n"));
-       return H_ENUMERATE_BAIL(held);
+       return H_ENUMERATE_BAIL(flags);
     }
 
     if (h->interface) {
@@ -2304,8 +2848,7 @@ h_stateVerifyHost(struct host * h, int held, struct fs_dump_state * state)
        state->bail = 1;
     }
 
- done:
-    return held;
+    return flags;
 }
 
 static int
@@ -2313,12 +2856,12 @@ h_stateVerifyAddrHash(struct fs_dump_state * state, struct host * h, afs_uint32
 {
     int ret = 0, found = 0;
     struct host *host = NULL;
-    struct h_hashChain *chain;
+    struct h_AddrHashChain *chain;
     int index = h_HashIndex(addr);
     char tmp[16];
     int chain_len = 0;
 
-    for (chain = hostHashTable[index]; chain; chain = chain->next) {
+    for (chain = hostAddrHashTable[index]; chain; chain = chain->next) {
        host = chain->hostPtr;
        if (host == NULL) {
            afs_inet_ntoa_r(addr, tmp);
@@ -2365,7 +2908,7 @@ h_stateVerifyUuidHash(struct fs_dump_state * state, struct host * h)
 {
     int ret = 0, found = 0;
     struct host *host = NULL;
-    struct h_hashChain *chain;
+    struct h_UuidHashChain *chain;
     afsUUID * uuidp = &h->interface->uuid;
     int index = h_UuidHashIndex(uuidp);
     char tmp[40];
@@ -2420,6 +2963,7 @@ h_stateFillHeader(struct host_state_header * hdr)
 {
     hdr->stamp.magic = HOST_STATE_MAGIC;
     hdr->stamp.version = HOST_STATE_VERSION;
+    return 0;
 }
 
 /* check the contents of the host state header structure */
@@ -2451,9 +2995,10 @@ h_stateAllocMap(struct fs_dump_state * state)
 
 /* function called by h_Enumerate to save a host to disk */
 static int
-h_stateSaveHost(register struct host * host, int held, struct fs_dump_state * state)
+h_stateSaveHost(struct host * host, int flags, void* rock)
 {
-    int i, if_len=0, hcps_len=0;
+    struct fs_dump_state *state = (struct fs_dump_state *) rock;
+    int if_len=0, hcps_len=0;
     struct hostDiskEntry hdsk;
     struct host_state_entry_header hdr;
     struct Interface * ifp = NULL;
@@ -2511,15 +3056,14 @@ h_stateSaveHost(register struct host * host, int held, struct fs_dump_state * st
 
     state->h_hdr->records++;
 
- done:
     if (ifp)
        free(ifp);
     if (hcps)
        free(hcps);
     if (state->bail) {
-       return H_ENUMERATE_BAIL(held);
+       return H_ENUMERATE_BAIL(flags);
     }
-    return held;
+    return flags;
 }
 
 /* restores a host from disk */
@@ -2602,15 +3146,19 @@ h_stateRestoreHost(struct fs_dump_state * state)
     h_diskEntryToHost_r(&hdsk, host);
     h_SetupCallbackConn_r(host);
 
+    h_AddHostToAddrHashTable_r(host->host, host->port, host);
     if (ifp) {
        int i;
        for (i = ifp->numberOfInterfaces-1; i >= 0; i--) {
-           h_AddHostToHashTable_r(ifp->interface[i].addr, 
-                                  ifp->interface[i].port, host);
+            if (ifp->interface[i].valid && 
+                !(ifp->interface[i].addr == host->host &&
+                  ifp->interface[i].port == host->port)) {
+                h_AddHostToAddrHashTable_r(ifp->interface[i].addr, 
+                                           ifp->interface[i].port, 
+                                           host);
+            }
        }
        h_AddHostToUuidHashTable_r(&ifp->uuid, host);
-    } else {
-       h_AddHostToHashTable_r(host->host, host->port, host);
     }
     h_InsertList_r(host);
 
@@ -2687,7 +3235,6 @@ h_OldToNew(struct fs_dump_state * state, afs_uint32 old, afs_uint32 * new)
        *new = state->h_map.entries[old].new_idx;
     }
 
- done:
     return ret;
 }
 #endif /* AFS_DEMAND_ATTACH_FS */
@@ -2704,9 +3251,10 @@ h_GetWorkStats(int *nump, int *activep, int *delp, afs_int32 cutofftime)
 {
     register struct host *host;
     register int num = 0, active = 0, del = 0;
+    int count;
 
     H_LOCK;
-    for (host = hostList; host; host = host->next) {
+    for (count = 0, host = hostList; host && count < hostCount; host = host->next, count++) {
        if (!(host->hostFlags & HOSTDELETED)) {
            num++;
            if (host->ActiveCall > cutofftime)
@@ -2715,6 +3263,12 @@ h_GetWorkStats(int *nump, int *activep, int *delp, afs_int32 cutofftime)
                del++;
        }
     }
+    if (count != hostCount) {
+       ViceLog(0, ("h_GetWorkStats found %d of %d hosts\n", count, hostCount));
+    } else if (host != NULL) {
+       ViceLog(0, ("h_GetWorkStats found more than %d hosts\n", hostCount));
+       ShutDownAndCore(PANIC);
+    }
     H_UNLOCK;
     if (nump)
        *nump = num;
@@ -2869,6 +3423,7 @@ h_GetHostNetStats(afs_int32 * a_numHostsP, afs_int32 * a_sameNetOrSubnetP,
 
     register struct host *hostP;       /*Ptr to current host entry */
     register afs_uint32 currAddr_HBO;  /*Curr host addr, host byte order */
+    int count;
 
     /*
      * Clear out the storage pointed to by our parameters.
@@ -2879,7 +3434,7 @@ h_GetHostNetStats(afs_int32 * a_numHostsP, afs_int32 * a_sameNetOrSubnetP,
     *a_diffNetworkP = (afs_int32) 0;
 
     H_LOCK;
-    for (hostP = hostList; hostP; hostP = hostP->next) {
+    for (count = 0, hostP = hostList; hostP && count < hostCount; hostP = hostP->next, count++) {
        if (!(hostP->hostFlags & HOSTDELETED)) {
            /*
             * Bump the number of undeleted host entries found.
@@ -2893,6 +3448,12 @@ h_GetHostNetStats(afs_int32 * a_numHostsP, afs_int32 * a_sameNetOrSubnetP,
                              a_diffNetworkP);
        }                       /*Only look at non-deleted hosts */
     }                          /*For each host record hashed to this index */
+    if (count != hostCount) {
+       ViceLog(0, ("h_GetHostNetStats found %d of %d hosts\n", count, hostCount));
+    } else if (hostP != NULL) {
+       ViceLog(0, ("h_GetHostNetStats found more than %d hosts\n", hostCount));
+       ShutDownAndCore(PANIC);
+    }
     H_UNLOCK;
 }                              /*h_GetHostNetStats */
 
@@ -2906,8 +3467,9 @@ static struct AFSFid zerofid;
  * Since it can serialize them, and pile up, it should be a separate LWP
  * from other events.
  */
+#if 0
 static int
-CheckHost(register struct host *host, int held)
+CheckHost(register struct host *host, int flags, void *rock)
 {
     register struct client *client;
     struct rx_connection *cb_conn = NULL;
@@ -2918,7 +3480,7 @@ CheckHost(register struct host *host, int held)
     FS_STATE_RDLOCK;
     if (fs_state.mode == FS_MODE_SHUTDOWN) {
        FS_STATE_UNLOCK;
-       return H_ENUMERATE_BAIL(held);
+       return H_ENUMERATE_BAIL(flags);
     }
     FS_STATE_UNLOCK;
 #endif
@@ -2934,6 +3496,7 @@ CheckHost(register struct host *host, int held)
     if (host->LastCall < checktime) {
        h_Lock_r(host);
        if (!(host->hostFlags & HOSTDELETED)) {
+            host->hostFlags |= HWHO_INPROGRESS;
            cb_conn = host->callback_rxcon;
            rx_GetConnection(cb_conn);
            if (host->LastCall < clientdeletetime) {
@@ -2965,11 +3528,13 @@ CheckHost(register struct host *host, int held)
                     * back state, because break delayed callbacks (called when a
                     * message is received from the workstation) will always send a 
                     * break all call backs to the workstation if there is no
-                    *callback.
+                    * callback.
                     */
                }
            } else {
                if (!(host->hostFlags & VENUSDOWN) && host->cblist) {
+                   char hoststr[16];
+                   (void)afs_inet_ntoa_r(host->host, hoststr);
                    if (host->interface) {
                        afsUUID uuid = host->interface->uuid;
                        H_UNLOCK;
@@ -2977,11 +3542,8 @@ CheckHost(register struct host *host, int held)
                        H_LOCK;
                        if (code) {
                            if (MultiProbeAlternateAddress_r(host)) {
-                               char hoststr[16];
-                               (void)afs_inet_ntoa_r(host->host, hoststr);
-                               ViceLog(0,
-                                       ("ProbeUuid failed for host %s:%d\n",
-                                        hoststr, ntohs(host->port)));
+                               ViceLog(0,("CheckHost: Probing all interfaces of host %s:%d failed, code %d\n",
+                                           hoststr, ntohs(host->port), code));
                                host->hostFlags |= VENUSDOWN;
                            }
                        }
@@ -2990,11 +3552,9 @@ CheckHost(register struct host *host, int held)
                        code = RXAFSCB_Probe(cb_conn);
                        H_LOCK;
                        if (code) {
-                           char hoststr[16];
-                           (void)afs_inet_ntoa_r(host->host, hoststr);
                            ViceLog(0,
-                                   ("Probe failed for host %s:%d\n", hoststr,
-                                    ntohs(host->port)));
+                                   ("CheckHost: Probe failed for host %s:%d, code %d\n", 
+                                    hoststr, ntohs(host->port), code));
                            host->hostFlags |= VENUSDOWN;
                        }
                    }
@@ -3004,6 +3564,7 @@ CheckHost(register struct host *host, int held)
            rx_PutConnection(cb_conn);
            cb_conn=NULL;
            H_LOCK;
+            host->hostFlags &= ~HWHO_INPROGRESS;
        }
        h_Unlock_r(host);
     }
@@ -3011,6 +3572,108 @@ CheckHost(register struct host *host, int held)
     return held;
 
 }                              /*CheckHost */
+#endif
+
+int
+CheckHost_r(register struct host *host, int flags, void *dummy)
+{
+    register struct client *client;
+    struct rx_connection *cb_conn = NULL;
+    int code;
+
+#ifdef AFS_DEMAND_ATTACH_FS
+    /* kill the checkhost lwp ASAP during shutdown */
+    FS_STATE_RDLOCK;
+    if (fs_state.mode == FS_MODE_SHUTDOWN) {
+       FS_STATE_UNLOCK;
+       return H_ENUMERATE_BAIL(flags);
+    }
+    FS_STATE_UNLOCK;
+#endif
+
+    /* Host is held by h_Enumerate_r */
+    for (client = host->FirstClient; client; client = client->next) {
+       if (client->refCount == 0 && client->LastCall < clientdeletetime) {
+           client->deleted = 1;
+           host->hostFlags |= CLIENTDELETED;
+       }
+    }
+    if (host->LastCall < checktime) {
+       h_Lock_r(host);
+       if (!(host->hostFlags & HOSTDELETED)) {
+           cb_conn = host->callback_rxcon;
+           rx_GetConnection(cb_conn);
+           if (host->LastCall < clientdeletetime) {
+               host->hostFlags |= HOSTDELETED;
+               if (!(host->hostFlags & VENUSDOWN)) {
+                   host->hostFlags &= ~ALTADDR;        /* alternate address invalid */
+                   if (host->interface) {
+                       H_UNLOCK;
+                       code =
+                           RXAFSCB_InitCallBackState3(cb_conn,
+                                                      &FS_HostUUID);
+                       H_LOCK;
+                   } else {
+                       H_UNLOCK;
+                       code =
+                           RXAFSCB_InitCallBackState(cb_conn);
+                       H_LOCK;
+                   }
+                   host->hostFlags |= ALTADDR; /* alternate addresses valid */
+                   if (code) {
+                       char hoststr[16];
+                       (void)afs_inet_ntoa_r(host->host, hoststr);
+                       ViceLog(0,
+                               ("CB: RCallBackConnectBack (host.c) failed for host %s:%d\n",
+                                hoststr, ntohs(host->port)));
+                       host->hostFlags |= VENUSDOWN;
+                   }
+                   /* Note:  it's safe to delete hosts even if they have call
+                    * back state, because break delayed callbacks (called when a
+                    * message is received from the workstation) will always send a 
+                    * break all call backs to the workstation if there is no
+                    * callback.
+                    */
+               }
+           } else {
+               if (!(host->hostFlags & VENUSDOWN) && host->cblist) {
+                   char hoststr[16];
+                   (void)afs_inet_ntoa_r(host->host, hoststr);
+                   if (host->interface) {
+                       afsUUID uuid = host->interface->uuid;
+                       H_UNLOCK;
+                       code = RXAFSCB_ProbeUuid(cb_conn, &uuid);
+                       H_LOCK;
+                       if (code) {
+                           if (MultiProbeAlternateAddress_r(host)) {
+                               ViceLog(0,("CheckHost_r: Probing all interfaces of host %s:%d failed, code %d\n",
+                                           hoststr, ntohs(host->port), code));
+                               host->hostFlags |= VENUSDOWN;
+                           }
+                       }
+                   } else {
+                       H_UNLOCK;
+                       code = RXAFSCB_Probe(cb_conn);
+                       H_LOCK;
+                       if (code) {
+                           ViceLog(0,
+                                   ("CheckHost_r: Probe failed for host %s:%d, code %d\n", 
+                                    hoststr, ntohs(host->port), code));
+                           host->hostFlags |= VENUSDOWN;
+                       }
+                   }
+               }
+           }
+           H_UNLOCK;
+           rx_PutConnection(cb_conn);
+           cb_conn=NULL;
+           H_LOCK;
+       }
+       h_Unlock_r(host);
+    }
+    return flags;
+
+}                              /*CheckHost_r */
 
 
 /*
@@ -3027,22 +3690,23 @@ h_CheckHosts(void)
 {
     afs_uint32 now = FT_ApproxTime();
 
-    memset((char *)&zerofid, 0, sizeof(zerofid));
+    memset(&zerofid, 0, sizeof(zerofid));
     /*
      * Send a probe to the workstation if it hasn't been heard from in
      * 15 minutes
      */
     checktime = now - 15 * 60;
     clientdeletetime = now - 120 * 60; /* 2 hours ago */
-    h_Enumerate(CheckHost, NULL);
-
+    
+    H_LOCK;
+    h_Enumerate_r(CheckHost_r, hostList, NULL);
+    H_UNLOCK;
 }                              /*h_CheckHosts */
 
 /*
  * This is called with host locked and held. At this point, the
- * hostHashTable should not have any entries for the alternate
- * interfaces. This function has to insert these entries in the
- * hostHashTable.
+ * hostAddrHashTable has an entry for the primary addr/port inserted
+ * by h_Alloc_r().  No other interfaces should be considered valid.
  *
  * The addresses in the interfaceAddr list are in host byte order.
  */
@@ -3055,28 +3719,62 @@ initInterfaceAddr_r(struct host *host, struct interfaceAddr *interf)
     afs_uint16 myPort;
     int found;
     struct Interface *interface;
+    char hoststr[16];
+    char uuidstr[128];
+    afs_uint16 port7001 = htons(7001);
 
     assert(host);
     assert(interf);
 
-    ViceLog(125,
-           ("initInterfaceAddr : host %x numAddr %d\n", host->host,
-            interf->numberOfInterfaces));
-
     number = interf->numberOfInterfaces;
     myAddr = host->host;       /* current interface address */
     myPort = host->port;       /* current port */
 
+    ViceLog(125,
+           ("initInterfaceAddr : host %s:%d numAddr %d\n", 
+             afs_inet_ntoa_r(myAddr, hoststr), ntohs(myPort), number));
+
     /* validation checks */
     if (number < 0 || number > AFS_MAX_INTERFACE_ADDR) {
        ViceLog(0,
-               ("Number of alternate addresses returned is %d\n", number));
+               ("Invalid number of alternate addresses is %d\n", number));
        return -1;
     }
 
     /*
-     * Convert IP addresses to network byte order, and remove for
-     * duplicate IP addresses from the interface list.
+     * The client's notion of its own IP addresses is not reliable.  
+     *
+     * 1. The client list might contain private address ranges which
+     *    are likely to be re-used by many clients allocated addresses
+     *    by a NAT.
+     *
+     * 2. The client list will not include any public addresses that
+     *    are hidden by a NAT.
+     *
+     * 3. Private address ranges that are exposed to the server will
+     *    be obtained from the rx connections that use them.
+     *
+     * 4. Lists provided by the client are not necessarily truthful.
+     *    Many existing clients (UNIX) do not refresh the IP address
+     *    list as the actual assigned addresses change.  The end result
+     *    is that they report the initial address list for the lifetime
+     *    of the process.  In other words, a client can report addresses
+     *    that they are in fact not using.  Adding these addresses to
+     *    the host interface list without verification is not only
+     *    pointless, it is downright dangerous.
+     *
+     * We therefore do not add alternate addresses to the addr hash table.
+     * We only use them for multi-rx callback breaks.
+     */
+
+    /*
+     * Convert IP addresses to network byte order, and remove
+     * duplicate IP addresses from the interface list, and 
+     * determine whether or not the incoming addr/port is 
+     * listed.  Note that if the address matches it is not
+     * truly a match because the port number for the entries
+     * in the interface list are port 7001 and the port number
+     * for this connection might not be 7001.
      */
     for (i = 0, count = 0, found = 0; i < number; i++) {
        interf->addr_in[i] = htonl(interf->addr_in[i]);
@@ -3086,7 +3784,8 @@ initInterfaceAddr_r(struct host *host, struct interfaceAddr *interf)
        }
        if (j == count) {
            interf->addr_in[count] = interf->addr_in[i];
-           if (interf->addr_in[count] == myAddr)
+           if (interf->addr_in[count] == myAddr &&
+                port7001 == myPort)
                found = 1;
            count++;
        }
@@ -3100,36 +3799,49 @@ initInterfaceAddr_r(struct host *host, struct interfaceAddr *interf)
            malloc(sizeof(struct Interface) +
                   (sizeof(struct AddrPort) * (count - 1)));
        if (!interface) {
-           ViceLog(0, ("Failed malloc in initInterfaceAddr_r\n"));
+           ViceLog(0, ("Failed malloc in initInterfaceAddr_r 1\n"));
            assert(0);
        }
        interface->numberOfInterfaces = count;
     } else {
        interface = (struct Interface *)
            malloc(sizeof(struct Interface) + (sizeof(struct AddrPort) * count));
-       assert(interface);
+       if (!interface) {
+           ViceLog(0, ("Failed malloc in initInterfaceAddr_r 2\n"));
+           assert(0);
+       }
        interface->numberOfInterfaces = count + 1;
        interface->interface[count].addr = myAddr;
        interface->interface[count].port = myPort;
+        interface->interface[count].valid = 1;
     }
-    interface->uuid = interf->uuid;
+
     for (i = 0; i < count; i++) {
-       interface->interface[i].addr = interf->addr_in[i];
+
+        interface->interface[i].addr = interf->addr_in[i];
        /* We store the port as 7001 because the addresses reported by 
         * TellMeAboutYourself and WhoAreYou RPCs are only valid if they
         * are coming from fully connected hosts (no NAT/PATs)
         */
-       interface->interface[i].port = htons(7001);
+       interface->interface[i].port = port7001;
+        interface->interface[i].valid = 
+            (interf->addr_in[i] == myAddr && port7001 == myPort) ? 1 : 0;
     }
 
+    interface->uuid = interf->uuid;
+
     assert(!host->interface);
     host->interface = interface;
 
-    for (i = 0; i < host->interface->numberOfInterfaces; i++) {
-       char hoststr[16];
-       ViceLog(125, ("--- alt address %s:%d\n", 
-                      afs_inet_ntoa_r(host->interface->interface[i].addr, hoststr),
-                      ntohs(host->interface->interface[i].port)));
+    if (LogLevel >= 125) {
+       afsUUID_to_string(&interface->uuid, uuidstr, 127);
+       
+       ViceLog(125, ("--- uuid %s\n", uuidstr));
+       for (i = 0; i < host->interface->numberOfInterfaces; i++) {
+           ViceLog(125, ("--- alt address %s:%d\n", 
+                         afs_inet_ntoa_r(host->interface->interface[i].addr, hoststr),
+                         ntohs(host->interface->interface[i].port)));
+       }
     }
 
     return 0;
@@ -3137,24 +3849,33 @@ initInterfaceAddr_r(struct host *host, struct interfaceAddr *interf)
 
 /* deleted a HashChain structure for this address and host */
 /* returns 1 on success */
-static int
-h_DeleteHostFromHashTableByAddr_r(afs_uint32 addr, afs_uint16 port, struct host *host)
+int
+h_DeleteHostFromAddrHashTable_r(afs_uint32 addr, afs_uint16 port, 
+                               struct host *host)
 {
-    int flag;
-    register struct h_hashChain **hp, *th;
+    char hoststr[16];
+    register struct h_AddrHashChain **hp, *th;
 
-    for (hp = &hostHashTable[h_HashIndex(addr)]; (th = *hp);) {
-       assert(th->hostPtr);
-       if (th->hostPtr == host && th->addr == addr && th->port == port) {
-           *hp = th->next;
-           free(th);
-           flag = 1;
-           break;
-       } else {
-           hp = &th->next;
-       }
+    if (addr == 0 && port == 0)
+       return 1;
+
+    for (hp = &hostAddrHashTable[h_HashIndex(addr)]; (th = *hp); 
+        hp = &th->next) {
+        assert(th->hostPtr);
+        if (th->hostPtr == host && th->addr == addr && th->port == port) {
+           ViceLog(125, ("h_DeleteHostFromAddrHashTable_r: host %" AFS_PTR_FMT " (%s:%d)\n",
+                         host, afs_inet_ntoa_r(host->host, hoststr),
+                         ntohs(host->port)));
+            *hp = th->next;
+            free(th);
+           return 1;
+        }
     }
-    return flag;
+    ViceLog(125, 
+           ("h_DeleteHostFromAddrHashTable_r: host %" AFS_PTR_FMT " (%s:%d) not found\n",
+            host, afs_inet_ntoa_r(host->host, hoststr), 
+            ntohs(host->port)));
+    return 0;
 }
 
 
@@ -3171,10 +3892,13 @@ printInterfaceAddr(struct host *host, int level)
     if (host->interface) {
        /* check alternate addresses */
        number = host->interface->numberOfInterfaces;
-       assert(number > 0);
-       for (i = 0; i < number; i++)
-           ViceLog(level, ("%s:%d ", afs_inet_ntoa_r(host->interface->interface[i].addr, hoststr),
-                            ntohs(host->interface->interface[i].port)));
+        if (number == 0) {
+            ViceLog(level, ("no-addresses "));
+       } else {
+            for (i = 0; i < number; i++)
+                ViceLog(level, ("%s:%d ", afs_inet_ntoa_r(host->interface->interface[i].addr, hoststr),
+                                ntohs(host->interface->interface[i].port)));
+        }
     }
     ViceLog(level, ("\n"));
 }