969061 - net-snmpd crash on time out

ABI breaking upstream patch.

commit 793d596838ff7cb48a73b675d62897c56c9e62df

Author: Jan Safranek <jsafranek@users.sourceforge.net>

Date:   Tue Jul 2 14:32:56 2013 +0200

    From: Jiri Cervenka: snmpd: Fixed agentx crashing and/or freezing on timeout.

    Queued requests are dropped gracefuly.

diff --git a/agent/mibgroup/agentx/master_admin.c b/agent/mibgroup/agentx/master_admin.c

index 999128a..4b42104 100644

--- a/agent/mibgroup/agentx/master_admin.c

+++ b/agent/mibgroup/agentx/master_admin.c

@@ -158,6 +158,7 @@ close_agentx_session(netsnmp_session * session, int sessid)

     for (sp = session->subsession; sp != NULL; sp = sp->next) {

         if (sp->sessid == sessid) {

+            netsnmp_remove_delegated_requests_for_session(sp);

             unregister_mibs_by_session(sp);

             unregister_index_by_session(sp);

             unregister_sysORTable_by_session(sp);

diff --git a/agent/snmp_agent.c b/agent/snmp_agent.c

index 1261c53..51eb287 100644

--- a/agent/snmp_agent.c

+++ b/agent/snmp_agent.c

@@ -1415,6 +1415,7 @@ init_agent_snmp_session(netsnmp_session * session, netsnmp_pdu *pdu)

     asp->treecache_num = -1;

     asp->treecache_len = 0;

     asp->reqinfo = SNMP_MALLOC_TYPEDEF(netsnmp_agent_request_info);

+    asp->flags = SNMP_AGENT_FLAGS_NONE;

     DEBUGMSGTL(("verbose:asp", "asp %p reqinfo %p created\n",

                 asp, asp->reqinfo));

@@ -1463,6 +1464,9 @@ netsnmp_check_for_delegated(netsnmp_agent_session *asp)

     if (NULL == asp->treecache)

         return 0;

+

+    if (asp->flags & SNMP_AGENT_FLAGS_CANCEL_IN_PROGRESS)

+        return 0;

     for (i = 0; i <= asp->treecache_num; i++) {

         for (request = asp->treecache[i].requests_begin; request;

@@ -1541,39 +1545,48 @@ int

 netsnmp_remove_delegated_requests_for_session(netsnmp_session *sess)

 {

     netsnmp_agent_session *asp;

-    int count = 0;

+    int total_count = 0;

     for (asp = agent_delegated_list; asp; asp = asp->next) {

         /*

          * check each request

          */

+        int i;

+        int count = 0;

         netsnmp_request_info *request;

-        for(request = asp->requests; request; request = request->next) {

-            /*

-             * check session

-             */

-            netsnmp_assert(NULL!=request->subtree);

-            if(request->subtree->session != sess)

-                continue;

+        for (i = 0; i <= asp->treecache_num; i++) {

+            for (request = asp->treecache[i].requests_begin; request;

+                 request = request->next) {

+                /*

+                 * check session

+                 */

+                netsnmp_assert(NULL!=request->subtree);

+                if(request->subtree->session != sess)

+                    continue;

-            /*

-             * matched! mark request as done

-             */

-            netsnmp_request_set_error(request, SNMP_ERR_GENERR);

-            ++count;

+                /*

+                 * matched! mark request as done

+                 */

+                netsnmp_request_set_error(request, SNMP_ERR_GENERR);

+                ++count;

+            }

+        }

+        if (count) {

+            asp->flags |= SNMP_AGENT_FLAGS_CANCEL_IN_PROGRESS;

+            total_count += count;

         }

     }

     /*

      * if we found any, that request may be finished now

      */

-    if(count) {

+    if(total_count) {

         DEBUGMSGTL(("snmp_agent", "removed %d delegated request(s) for session "

-                    "%8p\n", count, sess));

-        netsnmp_check_outstanding_agent_requests();

+                    "%8p\n", total_count, sess));

+        netsnmp_check_delegated_requests();

     }

-    return count;

+    return total_count;

 }

 int

@@ -2745,19 +2758,11 @@ handle_var_requests(netsnmp_agent_session *asp)

     return final_status;

 }

-/*

- * loop through our sessions known delegated sessions and check to see

- * if they've completed yet. If there are no more delegated sessions,

- * check for and process any queued requests

- */

 void

-netsnmp_check_outstanding_agent_requests(void)

+netsnmp_check_delegated_requests(void)

 {

     netsnmp_agent_session *asp, *prev_asp = NULL, *next_asp = NULL;

-    /*

-     * deal with delegated requests

-     */

     for (asp = agent_delegated_list; asp; asp = next_asp) {

         next_asp = asp->next;   /* save in case we clean up asp */

         if (!netsnmp_check_for_delegated(asp)) {

@@ -2796,6 +2801,22 @@ netsnmp_check_outstanding_agent_requests(void)

             prev_asp = asp;

         }

     }

+}

+

+/*

+ * loop through our sessions known delegated sessions and check to see

+ * if they've completed yet. If there are no more delegated sessions,

+ * check for and process any queued requests

+ */

+void

+netsnmp_check_outstanding_agent_requests(void)

+{

+    netsnmp_agent_session *asp;

+

+    /*

+     * deal with delegated requests

+     */

+    netsnmp_check_delegated_requests();

     /*

      * if we are processing a set and there are more delegated

@@ -2825,7 +2846,8 @@ netsnmp_check_outstanding_agent_requests(void)

             netsnmp_processing_set = netsnmp_agent_queued_list;

             DEBUGMSGTL(("snmp_agent", "SET request remains queued while "

-                        "delegated requests finish, asp = %8p\n", asp));

+                        "delegated requests finish, asp = %8p\n",

+                        agent_delegated_list));

             break;

         }

 #endif /* NETSNMP_NO_WRITE_SUPPORT */

@@ -2886,6 +2908,10 @@ check_delayed_request(netsnmp_agent_session *asp)

     case SNMP_MSG_GETBULK:

     case SNMP_MSG_GETNEXT:

         netsnmp_check_all_requests_status(asp, 0);

+        if (asp->flags & SNMP_AGENT_FLAGS_CANCEL_IN_PROGRESS) {

+            DEBUGMSGTL(("snmp_agent","canceling next walk for asp %p\n", asp));

+            break;

+        }

         handle_getnext_loop(asp);

         if (netsnmp_check_for_delegated(asp) &&

             netsnmp_check_transaction_id(asp->pdu->transid) !=

diff --git a/include/net-snmp/agent/snmp_agent.h b/include/net-snmp/agent/snmp_agent.h

index aad8837..43f4fff 100644

--- a/include/net-snmp/agent/snmp_agent.h

+++ b/include/net-snmp/agent/snmp_agent.h

@@ -32,6 +32,9 @@ extern          "C" {

 #define SNMP_MAX_PDU_SIZE 64000 /* local constraint on PDU size sent by agent

                                  * (see also SNMP_MAX_MSG_SIZE in snmp_api.h) */

+#define SNMP_AGENT_FLAGS_NONE                   0x0

+#define SNMP_AGENT_FLAGS_CANCEL_IN_PROGRESS     0x1

+

     /*

      * If non-zero, causes the addresses of peers to be logged when receptions

      * occur.  

@@ -205,6 +208,7 @@ extern          "C" {

         int             treecache_num;  /* number of current cache entries */

         netsnmp_cachemap *cache_store;

         int             vbcount;

+        int             flags;

     } netsnmp_agent_session;

     /*

@@ -240,6 +244,7 @@ extern          "C" {

     int             init_master_agent(void);

     void            shutdown_master_agent(void);

     int             agent_check_and_process(int block);

+    void            netsnmp_check_delegated_requests(void);

     void            netsnmp_check_outstanding_agent_requests(void);

     int             netsnmp_request_set_error(netsnmp_request_info *request,