This is a combined patch taken from the community merging 2 patches

for issues related to incorrect reporting of interface details when 

interfaces are changed dynamically. 

The following are the community bug/patch details.

snmpd: BUG: 1400101: remove deleted interfaces from ifTable

http://sourceforge.net/p/net-snmp/patches/640/

snmpd: PATCH: 1849903: from jsafranek: do not spam log with asserts when XEN is used

http://sourceforge.net/p/net-snmp/patches/872/

--- net-snmp-5.4.1.old/agent/mibgroup/if-mib/data_access/interface.c	2007-01-22 08:18:29.000000000 -0800

+++ net-snmp-5.4.1/agent/mibgroup/if-mib/data_access/interface.c	2013-07-11 13:27:55.792579500 -0700

@@ -465,8 +465,13 @@

         DEBUGMSGTL(("access:interface:ifIndex", "saved ifIndex %d for %s\n",

                     index, name));

     }

-    else

-        netsnmp_assert(index == tmp);

+    else {

+       if(index != tmp) {

+         se_remove_value_from_slist("interfaces", name);

+         se_add_pair_to_slist("interfaces", strdup(name), index);

+         DEBUGMSGTL(("access:interface:ifIndex", "ifname %s, old index %d, already existing, replaced with %d\n", name, tmp, index));

+       }      

+    }

 }

 /**

--- net-snmp-5.4.1.old/agent/mibgroup/if-mib/ifTable/ifTable_data_access.c	2007-02-05 07:10:28.000000000 -0800

+++ net-snmp-5.4.1/agent/mibgroup/if-mib/ifTable/ifTable_data_access.c	2013-07-11 14:39:08.458138600 -0700

@@ -23,6 +23,12 @@

 #   include "mibgroup/ip-mib/ipv4InterfaceTable/ipv4InterfaceTable.h"

 #endif

+typedef struct cd_container_s {

+    netsnmp_container *current;

+    netsnmp_container *deleted;

+} cd_container;

+

+

 /*

  * flag so we know not to set row/table last change times

  * during startup.

@@ -158,9 +164,11 @@

  */

 static void

 _check_interface_entry_for_updates(ifTable_rowreq_ctx * rowreq_ctx,

-                                   netsnmp_container *ifcontainer)

+                                   cd_container *cdc)

 {

     char            oper_changed = 0;

+    u_long lastchange = rowreq_ctx->data.ifLastChange;

+    netsnmp_container *ifcontainer = cdc->current;

     /*

      * check for matching entry. We can do this directly, since

@@ -192,17 +200,32 @@

          * deleted (and thus need to update ifTableLastChanged)?

          */

         if (!rowreq_ctx->known_missing) {

-            DEBUGMSGTL(("ifTable:access", "updating missing entry\n"));

             rowreq_ctx->known_missing = 1;

+            DEBUGMSGTL(("ifTable:access", "updating missing entry %s\n",rowreq_ctx->data.ifName));

             rowreq_ctx->data.ifAdminStatus = IFADMINSTATUS_DOWN;

-            if ((!(rowreq_ctx->data.ifentry->ns_flags & NETSNMP_INTERFACE_FLAGS_HAS_LASTCHANGE))

-                && (rowreq_ctx->data.ifOperStatus != IFOPERSTATUS_DOWN))

-                oper_changed = 1;

             rowreq_ctx->data.ifOperStatus = IFOPERSTATUS_DOWN;

+            rowreq_ctx->data.ifOperStatus = IFOPERSTATUS_DOWN;

+            oper_changed = 1;

+        } else {

+            time_t now = netsnmp_get_agent_uptime();

+            u_long diff = (now - rowreq_ctx->data.ifLastChange) / 100;

+            DEBUGMSGTL(("verbose:ifTable:access", "missing entry for %ld seconds\n", diff));

+            if (diff > IFTABLE_REMOVE_MISSING_AFTER) {

+                DEBUGMSGTL(("ifTable:access", "marking missing entry %s for "

+                            "removal after %d seconds\n", rowreq_ctx->data.ifName,

+                            IFTABLE_REMOVE_MISSING_AFTER));

+                if (NULL == cdc->deleted)

+                   cdc->deleted = netsnmp_container_find("ifTable_deleted:linked_list");

+                if (NULL == cdc->deleted)

+                   snmp_log(LOG_ERR, "couldn't create container for deleted interface\n");

+                else {

+                   CONTAINER_INSERT(cdc->deleted, rowreq_ctx);

+                }

+            }

         }

     } else {

-        DEBUGMSGTL(("ifTable:access", "updating existing entry\n"));

-

+        DEBUGMSGTL(("ifTable:access", "updating existing entry %s\n",

+                    rowreq_ctx->data.ifName));

 #ifdef USING_IF_MIB_IFXTABLE_IFXTABLE_MODULE

         {

             int rc = strcmp(rowreq_ctx->data.ifName,

@@ -245,6 +268,8 @@

      */

     if (oper_changed)

         rowreq_ctx->data.ifLastChange = netsnmp_get_agent_uptime();

+    else

+        rowreq_ctx->data.ifLastChange = lastchange;

 }

@@ -255,8 +280,21 @@

 _add_new_interface(netsnmp_interface_entry *ifentry,

                    netsnmp_container *container)

 {

-    ifTable_rowreq_ctx *rowreq_ctx;

-

+    ifTable_rowreq_ctx *rowreq_ctx, *container_entry;

+    netsnmp_iterator *ctxit;

+    ctxit = CONTAINER_ITERATOR(container);

+    container_entry = ITERATOR_FIRST(ctxit);

+

+    for(; container_entry; container_entry = ITERATOR_NEXT(ctxit)) {

+	if(!strcmp(ifentry->name, container_entry->data.ifName) && \

+	    ifentry->index != container_entry->data.ifentry->index) {

+		DEBUGMSGTL(("ifTable:access", "removing old entry %s (index %d != %d)\n",

+		    container_entry->data.ifName, container_entry->data.ifentry->index, ifentry->index));

+		    se_remove_value_from_slist("interfaces", container_entry->data.ifName);

+		CONTAINER_REMOVE(container, container_entry);

+		ifTable_release_rowreq_ctx(container_entry);

+		}

+    }

     DEBUGMSGTL(("ifTable:access", "creating new entry\n"));

     /*

@@ -300,6 +338,21 @@

         }

     }

 }

+ 

+/**

+ * delete removed entry

+ */

+static void

+_delete_missing_interface(ifTable_rowreq_ctx *rowreq_ctx,

+                          netsnmp_container *container)

+{

+    DEBUGMSGTL(("ifTable:access", "removing missing entry %s\n",

+                rowreq_ctx->data.ifName));

+

+    CONTAINER_REMOVE(container, rowreq_ctx);

+

+    ifTable_release_rowreq_ctx(rowreq_ctx);

+}

 /**

  * container shutdown

@@ -365,8 +418,7 @@

 int

 ifTable_container_load(netsnmp_container *container)

 {

-    netsnmp_container *ifcontainer;

-

+    cd_container cdc;	

     DEBUGMSGTL(("verbose:ifTable:ifTable_container_load", "called\n"));

     /*

@@ -378,31 +430,42 @@

     /*

      * ifTable gets its data from the netsnmp_interface API.

      */

-    ifcontainer =

+    cdc.current =

         netsnmp_access_interface_container_load(NULL,

                                                 NETSNMP_ACCESS_INTERFACE_INIT_NOFLAGS);

-    if (NULL == ifcontainer)

+    if (NULL == cdc.current)

         return MFD_RESOURCE_UNAVAILABLE;        /* msg already logged */

+    cdc.deleted = NULL; /* created as needed */

+

     /*

      * we just got a fresh copy of interface data. compare it to

      * what we've already got, and make any adjustements...

      */

     CONTAINER_FOR_EACH(container, (netsnmp_container_obj_func *)

-                       _check_interface_entry_for_updates, ifcontainer);

+                       _check_interface_entry_for_updates, &cdc);

     /*

      * now add any new interfaces

      */

-    CONTAINER_FOR_EACH(ifcontainer,

+    CONTAINER_FOR_EACH(cdc.current,

                        (netsnmp_container_obj_func *) _add_new_interface,

                        container);

+

+     /*

+     * now remove any missing interfaces

+     */

+    if (NULL != cdc.deleted)

+       CONTAINER_FOR_EACH(cdc.deleted,

+                          (netsnmp_container_obj_func *) _delete_missing_interface,

+                          container);

+

     /*

      * free the container. we've either claimed each ifentry, or released it,

      * so the dal function doesn't need to clear the container.

      */

-    netsnmp_access_interface_container_free(ifcontainer,

+    netsnmp_access_interface_container_free(cdc.current,

                                             NETSNMP_ACCESS_INTERFACE_FREE_DONT_CLEAR);

     DEBUGMSGT(("verbose:ifTable:ifTable_cache_load",

--- net-snmp-5.4.1.old/agent/mibgroup/if-mib/ifTable/ifTable_data_access.h	2006-04-09 21:59:10.000000000 -0700

+++ net-snmp-5.4.1/agent/mibgroup/if-mib/ifTable/ifTable_data_access.h	2013-07-11 13:58:33.862743400 -0700

@@ -48,6 +48,8 @@

      */

 #define IFTABLE_CACHE_TIMEOUT   15

+#define IFTABLE_REMOVE_MISSING_AFTER     (5 * 60) /* seconds */

+

     void            ifTable_container_init(netsnmp_container

                                            **container_ptr_ptr,

                                            netsnmp_cache * cache);

--- net-snmp-5.4.1.old/snmplib/snmp_enum.c	2005-02-09 11:46:35.000000000 -0800

+++ net-snmp-5.4.1/snmplib/snmp_enum.c	2013-07-10 04:08:50.542006500 -0700

@@ -213,6 +213,28 @@

     return SE_DNE;              /* XXX: um, no good solution here */

 }

+int se_remove_value_from_list(struct snmp_enum_list **list, const char *label)

+{

+   struct snmp_enum_list *lastlist;

+   if(!list)

+     return SE_DNE;

+

+   lastlist = NULL;

+   while(*list) {

+      if(strcmp((*list)->label, label) == 0) {

+	 free((*list)->label);

+	 if(lastlist)

+	   lastlist->next = (*list)->next;

+	 free(*list);

+	 *list = NULL;

+	 return 0;

+      }

+      lastlist = *list;

+      (*list) = (*list)->next;

+   }

+   

+}

+

 int

 se_find_free_value_in_list(struct snmp_enum_list *list)

 {

@@ -337,6 +359,19 @@

     return (se_find_free_value_in_list(se_find_slist(listname)));

 }

+void se_remove_value_from_slist(const char *listname, const char *label)

+{

+   struct snmp_enum_list_str *sptr, *lastp = NULL;

+   struct snmp_enum_list *list;

+   if (!listname)

+     return;

+

+   for (sptr = sliststorage;

+	sptr != NULL; lastp = sptr, sptr = sptr->next)

+     if (sptr->name && strcmp(sptr->name, listname) == 0)

+       se_remove_value_from_list(&sptr->list, label);

+}

+

 int

 se_add_pair_to_slist(const char *listname, char *label, int value)

 {