[snmpd]: Fix snmpd crash possible when snmp agent takes too long to respond. (#3454)
Patch from source-forge: net-snmp. Crash due to stale memory access.
This commit is contained in:
Renuka Manavalan
lguohan
parent
9cde0fc808
commit
cb81e3ab1e
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From a5782d0673044ad0c621daed7975f53238bb038e Mon Sep 17 00:00:00 2001
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From: Renuka Manavalan <remanava@microsoft.com>
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Date: Tue, 10 Sep 2019 17:51:45 +0000
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Subject: [PATCH] Patch from SourceForge: net-snmp commit #793d59 Avoids snmpd
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crash when sub agent timesout.
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---
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agent/mibgroup/agentx/master_admin.c | 1 +
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agent/snmp_agent.c | 81 ++++++++++++++++++----------
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include/net-snmp/agent/snmp_agent.h | 5 ++
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3 files changed, 60 insertions(+), 27 deletions(-)
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diff --git a/agent/mibgroup/agentx/master_admin.c b/agent/mibgroup/agentx/master_admin.c
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index 4dc1aa7..8c1d194 100644
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--- a/agent/mibgroup/agentx/master_admin.c
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+++ b/agent/mibgroup/agentx/master_admin.c
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@@ -158,6 +158,7 @@ close_agentx_session(netsnmp_session * session, int sessid)
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for (sp = session->subsession; sp != NULL; sp = sp->next) {
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if (sp->sessid == sessid) {
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+ netsnmp_remove_delegated_requests_for_session(sp);
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unregister_mibs_by_session(sp);
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unregister_index_by_session(sp);
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unregister_sysORTable_by_session(sp);
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diff --git a/agent/snmp_agent.c b/agent/snmp_agent.c
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index b96d650..7cacd1a 100644
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--- a/agent/snmp_agent.c
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+++ b/agent/snmp_agent.c
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@@ -1409,6 +1409,7 @@ init_agent_snmp_session(netsnmp_session * session, netsnmp_pdu *pdu)
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asp->treecache_num = -1;
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asp->treecache_len = 0;
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asp->reqinfo = SNMP_MALLOC_TYPEDEF(netsnmp_agent_request_info);
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+ asp->flags = SNMP_AGENT_FLAGS_NONE;
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DEBUGMSGTL(("verbose:asp", "asp %p reqinfo %p created\n",
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asp, asp->reqinfo));
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@@ -1457,6 +1458,9 @@ netsnmp_check_for_delegated(netsnmp_agent_session *asp)
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if (NULL == asp->treecache)
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return 0;
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+
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+ if (asp->flags & SNMP_AGENT_FLAGS_CANCEL_IN_PROGRESS)
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+ return 0;
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for (i = 0; i <= asp->treecache_num; i++) {
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for (request = asp->treecache[i].requests_begin; request;
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@@ -1535,39 +1539,48 @@ int
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netsnmp_remove_delegated_requests_for_session(netsnmp_session *sess)
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{
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netsnmp_agent_session *asp;
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- int count = 0;
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+ int total_count = 0;
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for (asp = agent_delegated_list; asp; asp = asp->next) {
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/*
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* check each request
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*/
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+ int i;
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+ int count = 0;
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netsnmp_request_info *request;
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- for(request = asp->requests; request; request = request->next) {
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- /*
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- * check session
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- */
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- netsnmp_assert(NULL!=request->subtree);
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- if(request->subtree->session != sess)
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- continue;
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+ for (i = 0; i <= asp->treecache_num; i++) {
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+ for (request = asp->treecache[i].requests_begin; request;
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+ request = request->next) {
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+ /*
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+ * check session
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+ */
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+ netsnmp_assert(NULL!=request->subtree);
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+ if(request->subtree->session != sess)
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+ continue;
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- /*
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- * matched! mark request as done
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- */
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- netsnmp_request_set_error(request, SNMP_ERR_GENERR);
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- ++count;
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+ /*
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+ * matched! mark request as done
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+ */
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+ netsnmp_request_set_error(request, SNMP_ERR_GENERR);
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+ ++count;
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+ }
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+ }
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+ if (count) {
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+ asp->flags |= SNMP_AGENT_FLAGS_CANCEL_IN_PROGRESS;
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+ total_count += count;
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}
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}
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/*
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* if we found any, that request may be finished now
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*/
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- if(count) {
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+ if(total_count) {
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DEBUGMSGTL(("snmp_agent", "removed %d delegated request(s) for session "
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- "%8p\n", count, sess));
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- netsnmp_check_outstanding_agent_requests();
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+ "%8p\n", total_count, sess));
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+ netsnmp_check_delegated_requests();
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}
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- return count;
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+ return total_count;
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}
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int
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@@ -2739,19 +2752,11 @@ handle_var_requests(netsnmp_agent_session *asp)
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return final_status;
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}
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-/*
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- * loop through our sessions known delegated sessions and check to see
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- * if they've completed yet. If there are no more delegated sessions,
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- * check for and process any queued requests
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- */
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void
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-netsnmp_check_outstanding_agent_requests(void)
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+netsnmp_check_delegated_requests(void)
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{
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netsnmp_agent_session *asp, *prev_asp = NULL, *next_asp = NULL;
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- /*
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- * deal with delegated requests
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- */
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for (asp = agent_delegated_list; asp; asp = next_asp) {
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next_asp = asp->next; /* save in case we clean up asp */
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if (!netsnmp_check_for_delegated(asp)) {
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@@ -2790,6 +2795,23 @@ netsnmp_check_outstanding_agent_requests(void)
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prev_asp = asp;
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}
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}
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+}
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+
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+
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+/*
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+ * loop through our sessions known delegated sessions and check to see
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+ * if they've completed yet. If there are no more delegated sessions,
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+ * check for and process any queued requests
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+ */
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+void
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+netsnmp_check_outstanding_agent_requests(void)
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+{
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+ netsnmp_agent_session *asp;
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+
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+ /*
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+ * deal with delegated requests
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+ */
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+ netsnmp_check_delegated_requests();
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/*
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* if we are processing a set and there are more delegated
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@@ -2819,7 +2841,8 @@ netsnmp_check_outstanding_agent_requests(void)
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netsnmp_processing_set = netsnmp_agent_queued_list;
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DEBUGMSGTL(("snmp_agent", "SET request remains queued while "
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- "delegated requests finish, asp = %8p\n", asp));
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+ "delegated requests finish, asp = %8p\n",
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+ agent_delegated_list));
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break;
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}
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#endif /* NETSNMP_NO_WRITE_SUPPORT */
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@@ -2880,6 +2903,10 @@ check_delayed_request(netsnmp_agent_session *asp)
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case SNMP_MSG_GETBULK:
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case SNMP_MSG_GETNEXT:
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netsnmp_check_all_requests_status(asp, 0);
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+ if (asp->flags & SNMP_AGENT_FLAGS_CANCEL_IN_PROGRESS) {
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+ DEBUGMSGTL(("snmp_agent","canceling next walk for asp %p\n", asp));
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+ break;
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+ }
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handle_getnext_loop(asp);
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if (netsnmp_check_for_delegated(asp) &&
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netsnmp_check_transaction_id(asp->pdu->transid) !=
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diff --git a/include/net-snmp/agent/snmp_agent.h b/include/net-snmp/agent/snmp_agent.h
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index aad8837..43f4fff 100644
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--- a/include/net-snmp/agent/snmp_agent.h
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+++ b/include/net-snmp/agent/snmp_agent.h
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@@ -32,6 +32,9 @@ extern "C" {
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#define SNMP_MAX_PDU_SIZE 64000 /* local constraint on PDU size sent by agent
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* (see also SNMP_MAX_MSG_SIZE in snmp_api.h) */
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+#define SNMP_AGENT_FLAGS_NONE 0x0
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+#define SNMP_AGENT_FLAGS_CANCEL_IN_PROGRESS 0x1
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+
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/*
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* If non-zero, causes the addresses of peers to be logged when receptions
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* occur.
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@@ -205,6 +208,7 @@ extern "C" {
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int treecache_num; /* number of current cache entries */
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netsnmp_cachemap *cache_store;
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int vbcount;
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+ int flags;
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} netsnmp_agent_session;
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/*
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@@ -240,6 +244,7 @@ extern "C" {
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int init_master_agent(void);
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void shutdown_master_agent(void);
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int agent_check_and_process(int block);
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+ void netsnmp_check_delegated_requests(void);
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void netsnmp_check_outstanding_agent_requests(void);
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int netsnmp_request_set_error(netsnmp_request_info *request,
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--
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2.17.1
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@ -2,3 +2,4 @@
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0002-at.c-properly-check-return-status-from-realloc.-Than.patch
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0002-at.c-properly-check-return-status-from-realloc.-Than.patch
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0003-CHANGES-BUG-2743-snmpd-crashes-when-receiving-a-GetN.patch
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0003-CHANGES-BUG-2743-snmpd-crashes-when-receiving-a-GetN.patch
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0004-Disable-SNMPv1.patch
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0004-Disable-SNMPv1.patch
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0006-From-Jiri-Cervenka-snmpd-Fixed-agentx-crashing-and-or-freezing-on-timeout.patch
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