[SNMP] management VRF SNMP support (#2608)

* [SNMP] management VRF SNMP support

This commit adds SNMP support for Management VRF using l3mdev.
The patch included provides VRF support, there is no single
"listendevice" configuration, rather multiple agentaddress
config options can each have their own "interface" to bind to
using "ip%interface". The snmpd.conf file is accordingly
generated using the snmp.yml file and redis database info.

Adding below the comments of SNMP patch 1376
--------------------------------------------
Since the Linux kernel added support for Virtual Routing
and Forwarding (VRF) in version 4.3
(Note: these won't compile on non-linux platforms)

https://www.kernel.org/doc/Documentation/networking/vrf.txt

Linux users could not use snmpd in its current form to
bind specific listening IP addresses to specific VRF
devices. A simplified description of a VRF inteface
is an interface that is a master (a container of sorts)
that collects a set of physicalinterfaces to form a
routing table.

This set of two patches (one for V5-7-patches and one
for V5-8-patches branches) is almost identical to patch
single "listendevice" configuration. Rather, multiple
agentAddress config options can each have their own
"interface" to bind to using the <ip>%<interface>
syntax.</interface></ip>
-------------------------------------------

Signed-off-by: Harish Venkatraman <harish_venkatraman@dell.com>

dockers/docker-snmp-sv2/snmpd.conf.j2

@@ -14,7 +14,21 @@
 #
 
 #  Listen for connections on all ip addresses, including eth0, ipv4 lo
+#
+{% if snmp_agent_address_1 or snmp_agent_address_2 or snmp_agent_address_3 %}
+{% if snmp_agent_address_1 %}
+agentAddress {{ snmp_agent_address_1 }}
+{% endif %}
+{% if snmp_agent_address_2 %}
+agentAddress {{ snmp_agent_address_2 }}
+{% endif %}
+{% if snmp_agent_address_3 %}
+agentAddress {{ snmp_agent_address_3 }}
+{% endif %}
+{% else %}
 agentAddress udp:161
+{% endif %}
+
 # TODO: only support ipv4 lo addresses, add ipv6 support later
 
 ###############################################################################
@@ -90,11 +104,23 @@ load   12 10 5
 # Note: disabled snmp traps due to side effect of causing snmpd to listen on all ports (0.0.0.0)
 #
 #   send SNMPv1  traps
+{%if v1_trap_dest and v1_trap_dest != 'NotConfigured' %}
+trapsink {{ v1_trap_dest }} public
+{% else %}
 #trapsink     localhost public
+{% endif %}
 #   send SNMPv2c traps
+{%if v2_trap_dest and v2_trap_dest != 'NotConfigured' %}
+trap2sink {{ v2_trap_dest }} public
+{% else %}
 #trap2sink    localhost public
+{% endif %}
 #   send SNMPv2c INFORMs
+{%if v3_trap_dest and v3_trap_dest != 'NotConfigured' %}
+informsink {{ v3_trap_dest }} public
+{% else %}
 #informsink   localhost public
+{% endif %}
 
 #  Note that you typically only want *one* of these three lines
 #  Uncommenting two (or all three) will result in multiple copies of each notification.

files/build_templates/docker_image_ctl.j2

@@ -109,6 +109,43 @@ function postStartAction()
     fi
 {%- elif docker_container_name == "snmp" %}
     docker exec -i database redis-cli -n 6 HSET 'DEVICE_METADATA|localhost' chassis_serial_number $(decode-syseeprom -s)
+    vrfenabled=`/usr/bin/redis-cli -n 4 hget "MGMT_VRF_CONFIG|vrf_global" mgmtVrfEnabled`
+    v1SnmpTrapIp=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v1TrapDest" DestIp`
+    v1SnmpTrapPort=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v1TrapDest" DestPort`
+    v1MgmtVrf=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v1TrapDest" vrf`
+    v2SnmpTrapIp=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v2TrapDest" DestIp`
+    v2SnmpTrapPort=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v2TrapDest" DestPort`
+    v2MgmtVrf=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v2TrapDest" vrf`
+    v3SnmpTrapIp=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v3TrapDest" DestIp`
+    v3SnmpTrapPort=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v3TrapDest" DestPort`
+    v3MgmtVrf=`/usr/bin/redis-cli -n 4 hget "SNMP_TRAP_CONFIG|v3TrapDest" vrf`
+    
+    if [ "${v1SnmpTrapIp}" != "" ]
+    then
+	sed -i "s/v1_trap_dest:.*/v1_trap_dest: ${v1SnmpTrapIp}:${v1SnmpTrapPort}%${v1MgmtVrf}/" "/etc/sonic/snmp.yml"
+    fi
+    if [ "${v2SnmpTrapIp}" != "" ]
+    then
+	sed -i "s/v2_trap_dest:.*/v2_trap_dest: ${v2SnmpTrapIp}:${v2SnmpTrapPort}%${v2MgmtVrf}/" "/etc/sonic/snmp.yml"
+    fi
+    if [ "${v3SnmpTrapIp}" != "" ]
+    then
+	sed -i "s/v3_trap_dest:.*/v3_trap_dest: ${v3SnmpTrapIp}:${v3SnmpTrapPort}%${v3MgmtVrf}/" "/etc/sonic/snmp.yml"
+    fi
+
+    if [ "${vrfenabled}" == "true" ]
+    then
+        keys=`/usr/bin/redis-cli -n 4 keys "SNMP_AGENT_ADDRESS_CONFIG|*"`
+	    count=1
+	    for key in $keys;do
+	        ip=`echo $key|cut -d "|" -f2`
+	        vrf=`echo $key|cut -d "|" -f3`
+	        echo "snmp_agent_address_$count: $ip%$vrf" >> /tmp/snmpagentaddr.yml
+	        count=$((count+1))
+        done
+        sed -i '/snmp_agent_address_*/d' /etc/sonic/snmp.yml
+        cat /tmp/snmpagentaddr.yml >> /etc/sonic/snmp.yml
+    fi
 {%- else %}
     : # nothing
 {%- endif %}

files/image_config/snmp/snmp.yml

@@ -1,2 +1,5 @@
 snmp_rocommunity: public
 snmp_location: public
+v1_trap_dest: NotConfigured
+v2_trap_dest: NotConfigured
+v3_trap_dest: NotConfigured

src/snmpd/patch-5.7.3+dfsg/0007-Linux-VRF-5.7.3-Support.patch

@@ -0,0 +1,786 @@
+From 49ce7fc078dfa8c1a1688e05de4e2d151dbcd76a Mon Sep 17 00:00:00 2001
+From: Harish Venkatraman <Harish_Venkatraman@dell.com>
+Date: Wed, 17 Oct 2018 15:22:04 -0700
+Subject: [PATCH] Linux-VRF 5.7.3 Support from https://sourceforge.net/p/net-snmp/patches/1376/
+
+Sourceforge commits related to this consolidated patch are given below.
+https://sourceforge.net/p/net-snmp/code/ci/0b637fea62c7b6dc467b94206d0bd2dec6f912ca/
+https://sourceforge.net/p/net-snmp/code/ci/19ba7b0a6b56d201a8563fe6505cd82e313c1c9c/
+https://sourceforge.net/p/net-snmp/code/ci/76336fb63bb74b4dede5dda5c14fb8cf2d60be8e/
+https://sourceforge.net/p/net-snmp/code/ci/c7398de4122102b3250e6dac7c09dbc5d09f1840/
+https://sourceforge.net/p/net-snmp/code/ci/0831ed64a39a34dc040eabe39d0229b07fa2a8a5/
+https://sourceforge.net/p/net-snmp/code/ci/62f6babcc7cfc54c79b442b8a7f45662b4ddc807/
+https://sourceforge.net/p/net-snmp/code/ci/313949522c4d0ddfeac72195fa63512955d9eb28/
+
+
+This consolidated patch adds native support for VRFs to snmpd. NCLU patches in this same
+CCR will be added shortly.  The VRF is specified for both listening
+addresses as well as TRAP sinks with the 'ipaddr%iface' syntax:
+
+agentAddress 10.0.1.7%mgmt,22.22.22.22%red
+trapsink 10.0.1.9%mgmt
+trap2sink 22.22.22.25%red
+
+The SO_BINDTODEVICE socket option is used to bind a VRF to a particular
+socket.
+
+Testing done included VRFs as well as non-VRF functionality with traps
+(v1, v2, and v3)
+
+---
+ agent/agent_trap.c                               | 20 ++++++++++--
+ agent/mibgroup/agentx/master.c                   |  2 +-
+ agent/mibgroup/agentx/subagent.c                 |  2 +-
+ agent/mibgroup/target/target.c                   |  3 +-
+ agent/snmp_agent.c                               | 21 ++++++++++++-
+ apps/agentxtrap.c                                |  2 +-
+ apps/snmptrap.c                                  |  2 +-
+ apps/snmptrapd.c                                 |  2 +-
+ include/net-snmp/library/snmpTCPDomain.h         |  2 +-
+ include/net-snmp/library/snmpUDPBaseDomain.h     |  2 +-
+ include/net-snmp/library/snmpUDPDomain.h         |  2 +-
+ include/net-snmp/library/snmpUDPIPv4BaseDomain.h |  2 +-
+ include/net-snmp/library/snmpUDPIPv6Domain.h     |  2 +-
+ include/net-snmp/library/snmp_transport.h        | 19 +++++++-----
+ snmplib/snmp_api.c                               |  4 +--
+ snmplib/snmp_transport.c                         | 26 ++++++++--------
+ snmplib/transports/snmpAliasDomain.c             |  6 ++--
+ snmplib/transports/snmpTCPDomain.c               | 16 +++++++---
+ snmplib/transports/snmpUDPBaseDomain.c           | 39 ++++++++++++++++++------
+ snmplib/transports/snmpUDPDomain.c               | 15 ++++-----
+ snmplib/transports/snmpUDPIPv4BaseDomain.c       |  4 +--
+ snmplib/transports/snmpUDPIPv6Domain.c           | 13 ++++----
+ snmplib/transports/snmpUnixDomain.c              |  5 +--
+ 23 files changed, 141 insertions(+), 70 deletions(-)
+
+diff --git a/agent/agent_trap.c b/agent/agent_trap.c
+index 080b8bf..c488ac9 100644
+--- a/agent/agent_trap.c
++++ b/agent/agent_trap.c
+@@ -226,6 +226,7 @@ create_trap_session2(const char *sink, const char* sinkport,
+ {
+     netsnmp_transport *t;
+     netsnmp_session session, *sesp;
++    char *iface;
+ 
+     memset(&session, 0, sizeof(netsnmp_session));
+     session.version = version;
+@@ -250,7 +251,14 @@ create_trap_session2(const char *sink, const char* sinkport,
+         ((0 == strcmp("localhost",sink)) || (0 == strcmp("127.0.0.1",sink))))
+         session.localname = strdup("localhost");
+ 
+-    t = netsnmp_tdomain_transport_full("snmptrap", sink, 0, NULL, sinkport);
++    /*
++     * if given an iface (ip%iface) in sink, send the iface too
++     */
++    iface = strchr(sink, '%');
++    if (iface)
++        *iface++ = '\0';
++
++    t = netsnmp_tdomain_transport_full("snmptrap", sink, 0, NULL, sinkport, iface);
+     if (t != NULL) {
+ 	sesp = snmp_add(&session, t, NULL, NULL);
+ 
+@@ -1219,6 +1227,7 @@ snmpd_parse_config_trapsess(const char *word, char *cptr)
+     netsnmp_session session, *ss;
+     netsnmp_transport *transport;
+     size_t          len;
++    char            *iface;
+ 
+     /*
+      * inform or trap?  default to trap 
+@@ -1240,7 +1249,14 @@ snmpd_parse_config_trapsess(const char *word, char *cptr)
+                        NETSNMP_PARSE_ARGS_NOLOGGING |
+                        NETSNMP_PARSE_ARGS_NOZERO);
+ 
+-    transport = netsnmp_transport_open_client("snmptrap", session.peername);
++    /*
++     * if iface is given in peer, we will need to bind to that iface
++     */
++    iface = strchr(session.peername, '%');
++    if (iface)
++	*iface++ = '\0';
++
++    transport = netsnmp_transport_open_client("snmptrap", session.peername, iface);
+     if (transport == NULL) {
+         config_perror("snmpd: failed to parse this line.");
+         return;
+diff --git a/agent/mibgroup/agentx/master.c b/agent/mibgroup/agentx/master.c
+index baeebaf..6733e7f 100644
+--- a/agent/mibgroup/agentx/master.c
++++ b/agent/mibgroup/agentx/master.c
+@@ -126,7 +126,7 @@ real_init_master(void)
+         sess.remote_port = 0;
+         sess.callback = handle_master_agentx_packet;
+         errno = 0;
+-        t = netsnmp_transport_open_server("agentx", sess.peername);
++        t = netsnmp_transport_open_server("agentx", sess.peername, NULL);
+         if (t == NULL) {
+             /*
+              * diagnose snmp_open errors with the input netsnmp_session
+diff --git a/agent/mibgroup/agentx/subagent.c b/agent/mibgroup/agentx/subagent.c
+index 1f9d31c..6d38a34 100644
+--- a/agent/mibgroup/agentx/subagent.c
++++ b/agent/mibgroup/agentx/subagent.c
+@@ -843,7 +843,7 @@ subagent_open_master_session(void)
+ 
+     agentx_socket = netsnmp_ds_get_string(NETSNMP_DS_APPLICATION_ID,
+                                           NETSNMP_DS_AGENT_X_SOCKET);
+-    t = netsnmp_transport_open_client("agentx", agentx_socket);
++    t = netsnmp_transport_open_client("agentx", agentx_socket, NULL);
+     if (t == NULL) {
+         /*
+          * Diagnose snmp_open errors with the input
+diff --git a/agent/mibgroup/target/target.c b/agent/mibgroup/target/target.c
+index 5619e35..6f58817 100644
+--- a/agent/mibgroup/target/target.c
++++ b/agent/mibgroup/target/target.c
+@@ -154,7 +154,8 @@ get_target_sessions(char *taglist, TargetFilterFunction * filterfunct,
+                                                               tAddress,
+                                                               targaddrs->
+                                                               tAddressLen,
+-                                                              0);
++                                                              0,
++							      NULL);
+                             if (t == NULL) {
+                                 DEBUGMSGTL(("target_sessions",
+                                             "bad dest \""));
+diff --git a/agent/snmp_agent.c b/agent/snmp_agent.c
+index b96d650..281e8b2 100644
+--- a/agent/snmp_agent.c
++++ b/agent/snmp_agent.c
+@@ -1270,6 +1270,7 @@ init_master_agent(void)
+     char           *cptr;
+     char           *buf = NULL;
+     char           *st;
++    char           *iface;
+ 
+     /* default to a default cache size */
+     netsnmp_set_lookup_cache_size(-1);
+@@ -1318,6 +1319,9 @@ init_master_agent(void)
+          * AAL5PVC:itf.vpi.vci        (if supported)
+          * IPX:[network]:node[/port] (if supported)
+          * 
++         *
++         * New format to specify an interface for binding along with IP address
++         *  address%iface
+          */
+ 
+ 	cptr = st;
+@@ -1334,7 +1338,22 @@ init_master_agent(void)
+ 			"requested\n"));
+             break;
+         }
+-        transport = netsnmp_transport_open_server("snmp", cptr);
++
++	/*
++	 * at some point, we may want to add the special listendevice
++	 * keyword support. Not sure how to interact with ip%iface
++	   iface = netsnmp_ds_get_string(NETSNMP_DS_APPLICATION_ID,
++				NETSNMP_DS_AGENT_LISTEN_DEVICE);
++	*/
++
++	/* Look for %iface so we can send along a specific interface to
++	   setsockopt SO_BINDTODEVICE later. */
++	iface = strchr(cptr, '%');
++	if (iface)
++	    *iface++ = '\0';
++
++	transport = netsnmp_transport_open_server("snmp", cptr, iface);
++ 
+ 
+         if (transport == NULL) {
+             snmp_log(LOG_ERR, "Error opening specified endpoint \"%s\"\n",
+diff --git a/apps/agentxtrap.c b/apps/agentxtrap.c
+index 4df423c..ebd81a3 100644
+--- a/apps/agentxtrap.c
++++ b/apps/agentxtrap.c
+@@ -231,7 +231,7 @@ ConnectingEntry(UNUSED tState self)
+ 
+     if(!(t = netsnmp_transport_open_client(
+              "agentx", netsnmp_ds_get_string(
+-                 NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_X_SOCKET)))) {
++                 NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_X_SOCKET), NULL))) {
+         snmp_log(LOG_ERR, "Failed to connect to AgentX server\n");
+         change_state(&Exit);
+     } else if(!(sess = snmp_sess_add_ex(
+diff --git a/apps/snmptrap.c b/apps/snmptrap.c
+index 7c086db..28d5257 100644
+--- a/apps/snmptrap.c
++++ b/apps/snmptrap.c
+@@ -215,7 +215,7 @@ main(int argc, char *argv[])
+     }
+ 
+     ss = snmp_add(&session,
+-                  netsnmp_transport_open_client("snmptrap", session.peername),
++                  netsnmp_transport_open_client("snmptrap", session.peername, NULL),
+                   NULL, NULL);
+     if (ss == NULL) {
+         /*
+diff --git a/apps/snmptrapd.c b/apps/snmptrapd.c
+index bce0d47..122a502 100644
+--- a/apps/snmptrapd.c
++++ b/apps/snmptrapd.c
+@@ -1186,7 +1186,7 @@ main(int argc, char *argv[])
+             *sep = 0;
+         }
+ 
+-        transport = netsnmp_transport_open_server("snmptrap", cp);
++        transport = netsnmp_transport_open_server("snmptrap", cp, NULL);
+         if (transport == NULL) {
+             snmp_log(LOG_ERR, "couldn't open %s -- errno %d (\"%s\")\n",
+                      cp, errno, strerror(errno));
+diff --git a/include/net-snmp/library/snmpTCPDomain.h b/include/net-snmp/library/snmpTCPDomain.h
+index c45856b..3b1fef5 100644
+--- a/include/net-snmp/library/snmpTCPDomain.h
++++ b/include/net-snmp/library/snmpTCPDomain.h
+@@ -25,7 +25,7 @@ extern          "C" {
+ #define TRANSPORT_DOMAIN_TCP_IP		1,3,6,1,2,1,100,1,5
+ NETSNMP_IMPORT oid netsnmp_snmpTCPDomain[];
+ 
+-netsnmp_transport *netsnmp_tcp_transport(struct sockaddr_in *addr, int local);
++netsnmp_transport *netsnmp_tcp_transport(struct sockaddr_in *addr, int local, char *iface);
+ 
+ /*
+  * "Constructor" for transport domain object.  
+diff --git a/include/net-snmp/library/snmpUDPBaseDomain.h b/include/net-snmp/library/snmpUDPBaseDomain.h
+index b9d2c34..0ab2fe5 100644
+--- a/include/net-snmp/library/snmpUDPBaseDomain.h
++++ b/include/net-snmp/library/snmpUDPBaseDomain.h
+@@ -18,7 +18,7 @@ extern          "C" {
+ /*
+  * Prototypes
+  */
+-    void _netsnmp_udp_sockopt_set(int fd, int local);
++    void _netsnmp_udp_sockopt_set(int fd, int local, char *iface);
+     int netsnmp_udpbase_recv(netsnmp_transport *t, void *buf, int size,
+                              void **opaque, int *olength);
+     int netsnmp_udpbase_send(netsnmp_transport *t, void *buf, int size,
+diff --git a/include/net-snmp/library/snmpUDPDomain.h b/include/net-snmp/library/snmpUDPDomain.h
+index 3a09dfd..e402cd8 100644
+--- a/include/net-snmp/library/snmpUDPDomain.h
++++ b/include/net-snmp/library/snmpUDPDomain.h
+@@ -18,7 +18,7 @@ extern          "C" {
+ config_require(UDPIPv4Base)
+ #include <net-snmp/library/snmpUDPIPv4BaseDomain.h>
+ 
+-netsnmp_transport *netsnmp_udp_transport(struct sockaddr_in *addr, int local);
++netsnmp_transport *netsnmp_udp_transport(struct sockaddr_in *addr, int local, char*iface);
+ 
+ 
+ /*
+diff --git a/include/net-snmp/library/snmpUDPIPv4BaseDomain.h b/include/net-snmp/library/snmpUDPIPv4BaseDomain.h
+index 6f7f2c2..8d3e906 100644
+--- a/include/net-snmp/library/snmpUDPIPv4BaseDomain.h
++++ b/include/net-snmp/library/snmpUDPIPv4BaseDomain.h
+@@ -25,7 +25,7 @@ extern          "C" {
+  */
+ 
+     netsnmp_transport *netsnmp_udpipv4base_transport(struct sockaddr_in *addr,
+-                                                     int local);
++                                                     int local, char *iface);
+ 
+ #if defined(HAVE_IP_PKTINFO) || defined(HAVE_IP_RECVDSTADDR)
+     int netsnmp_udpipv4_recvfrom(int s, void *buf, int len,
+diff --git a/include/net-snmp/library/snmpUDPIPv6Domain.h b/include/net-snmp/library/snmpUDPIPv6Domain.h
+index 83eba2c..009c510 100644
+--- a/include/net-snmp/library/snmpUDPIPv6Domain.h
++++ b/include/net-snmp/library/snmpUDPIPv6Domain.h
+@@ -23,7 +23,7 @@ config_require(UDPBase)
+ NETSNMP_IMPORT oid      netsnmp_UDPIPv6Domain[];
+ 
+ netsnmp_transport *netsnmp_udp6_transport(struct sockaddr_in6 *addr,
+-                                          int local);
++                                          int local, char *iface);
+ 
+ 
+ /*
+diff --git a/include/net-snmp/library/snmp_transport.h b/include/net-snmp/library/snmp_transport.h
+index 4162897..a3deda7 100644
+--- a/include/net-snmp/library/snmp_transport.h
++++ b/include/net-snmp/library/snmp_transport.h
+@@ -206,14 +206,14 @@ typedef struct netsnmp_tdomain_s {
+      * The f_create_from_tstring field is deprecated, please do not use it
+      * for new code and try to migrate old code away from using it.
+      */
+-    netsnmp_transport *(*f_create_from_tstring) (const char *, int);
++    netsnmp_transport *(*f_create_from_tstring) (const char *, int, char *);
+ 
+-    netsnmp_transport *(*f_create_from_ostring) (const u_char *, size_t, int);
++    netsnmp_transport *(*f_create_from_ostring) (const u_char *, size_t, int, char *);
+ 
+     struct netsnmp_tdomain_s *next;
+ 
+     netsnmp_transport *(*f_create_from_tstring_new) (const char *, int,
+-						     const char*);
++						     const char*, char *);
+ 
+ } netsnmp_tdomain;
+ 
+@@ -273,29 +273,32 @@ void            netsnmp_tdomain_init(void);
+ NETSNMP_IMPORT
+ netsnmp_transport *netsnmp_tdomain_transport(const char *str,
+ 					     int local,
+-					     const char *default_domain);
++					     const char *default_domain,
++					     char *iface);
+ 
+ NETSNMP_IMPORT
+ netsnmp_transport *netsnmp_tdomain_transport_full(const char *application,
+ 						  const char *str,
+ 						  int local,
+ 						  const char *default_domain,
+-						  const char *default_target);
++						  const char *default_target,
++						  char *iface);
+ 
+ NETSNMP_IMPORT
+ netsnmp_transport *netsnmp_tdomain_transport_oid(const oid * dom,
+ 						 size_t dom_len,
+ 						 const u_char * o,
+ 						 size_t o_len,
+-						 int local);
++						 int local,
++						 char *iface);
+ 
+ NETSNMP_IMPORT
+ netsnmp_transport*
+-netsnmp_transport_open_client(const char* application, const char* str);
++netsnmp_transport_open_client(const char* application, const char* str, char *iface);
+ 
+ NETSNMP_IMPORT
+ netsnmp_transport*
+-netsnmp_transport_open_server(const char* application, const char* str);
++netsnmp_transport_open_server(const char* application, const char* str, char *iface);
+ 
+ netsnmp_transport*
+ netsnmp_transport_open(const char* application, const char* str, int local);
+diff --git a/snmplib/snmp_api.c b/snmplib/snmp_api.c
+index d155c99..5128c56 100644
+--- a/snmplib/snmp_api.c
++++ b/snmplib/snmp_api.c
+@@ -1557,12 +1557,12 @@ _sess_open(netsnmp_session * in_session)
+             transport =
+                 netsnmp_tdomain_transport_full("snmp", in_session->peername,
+                                                in_session->local_port, "tcp,tcp6",
+-                                               NULL);
++                                               NULL, NULL);
+         } else {
+             transport =
+                 netsnmp_tdomain_transport_full("snmp", in_session->peername,
+                                                in_session->local_port, "udp,udp6",
+-                                               NULL);
++                                               NULL, NULL);
+         }
+ 
+         if (NULL != clientaddr_save)
+diff --git a/snmplib/snmp_transport.c b/snmplib/snmp_transport.c
+index ada4781..40cd631 100644
+--- a/snmplib/snmp_transport.c
++++ b/snmplib/snmp_transport.c
+@@ -491,7 +491,8 @@ netsnmp_transport *
+ netsnmp_tdomain_transport_full(const char *application,
+                                const char *str, int local,
+                                const char *default_domain,
+-                               const char *default_target)
++                               const char *default_target,
++			       char *iface)
+ {
+     netsnmp_tdomain    *match = NULL;
+     const char         *addr = NULL;
+@@ -646,10 +647,10 @@ netsnmp_tdomain_transport_full(const char *application,
+                 NETSNMP_LOGONCE((LOG_WARNING,
+                                  "transport domain %s uses deprecated f_create_from_tstring\n",
+                                  match->prefix[0]));
+-                t = match->f_create_from_tstring(addr, local);
++                t = match->f_create_from_tstring(addr, local, iface);
+             }
+             else
+-                t = match->f_create_from_tstring_new(addr, local, addr2);
++                t = match->f_create_from_tstring_new(addr, local, addr2, iface);
+             if (t) {
+                 if (lspec) {
+                     free(lspec[0]);
+@@ -676,10 +677,11 @@ netsnmp_tdomain_transport_full(const char *application,
+ 
+ netsnmp_transport *
+ netsnmp_tdomain_transport(const char *str, int local,
+-			  const char *default_domain)
++			  const char *default_domain,
++			  char *iface)
+ {
+     return netsnmp_tdomain_transport_full("snmp", str, local, default_domain,
+-					  NULL);
++					  NULL, iface);
+ }
+ 
+ 
+@@ -687,7 +689,7 @@ netsnmp_tdomain_transport(const char *str, int local,
+ netsnmp_transport *
+ netsnmp_tdomain_transport_oid(const oid * dom,
+                               size_t dom_len,
+-                              const u_char * o, size_t o_len, int local)
++                              const u_char * o, size_t o_len, int local, char *iface)
+ {
+     netsnmp_tdomain *d;
+     int             i;
+@@ -700,7 +702,7 @@ netsnmp_tdomain_transport_oid(const oid * dom,
+         for (i = 0; d->prefix[i] != NULL; i++) {
+             if (netsnmp_oid_equals(dom, dom_len, d->name, d->name_length) ==
+                 0) {
+-                return d->f_create_from_ostring(o, o_len, local);
++                return d->f_create_from_ostring(o, o_len, local, iface);
+             }
+         }
+     }
+@@ -713,19 +715,19 @@ netsnmp_tdomain_transport_oid(const oid * dom,
+ netsnmp_transport*
+ netsnmp_transport_open(const char* application, const char* str, int local)
+ {
+-    return netsnmp_tdomain_transport_full(application, str, local, NULL, NULL);
++    return netsnmp_tdomain_transport_full(application, str, local, NULL, NULL, NULL);
+ }
+ 
+ netsnmp_transport*
+-netsnmp_transport_open_server(const char* application, const char* str)
++netsnmp_transport_open_server(const char* application, const char* str, char *iface)
+ {
+-    return netsnmp_tdomain_transport_full(application, str, 1, NULL, NULL);
++    return netsnmp_tdomain_transport_full(application, str, 1, NULL, NULL, iface);
+ }
+ 
+ netsnmp_transport*
+-netsnmp_transport_open_client(const char* application, const char* str)
++netsnmp_transport_open_client(const char* application, const char* str, char *iface)
+ {
+-    return netsnmp_tdomain_transport_full(application, str, 0, NULL, NULL);
++    return netsnmp_tdomain_transport_full(application, str, 0, NULL, NULL, iface);
+ }
+ 
+ /** adds a transport to a linked list of transports.
+diff --git a/snmplib/transports/snmpAliasDomain.c b/snmplib/transports/snmpAliasDomain.c
+index eb50cad..dd7a007 100644
+--- a/snmplib/transports/snmpAliasDomain.c
++++ b/snmplib/transports/snmpAliasDomain.c
+@@ -75,7 +75,7 @@ free_alias_config(void) {
+ 
+ netsnmp_transport *
+ netsnmp_alias_create_tstring(const char *str, int local,
+-			   const char *default_target)
++			   const char *default_target, char *iface)
+ {
+     const char *aliasdata;
+ 
+@@ -85,13 +85,13 @@ netsnmp_alias_create_tstring(const char *str, int local,
+         return NULL;
+     }
+ 
+-    return netsnmp_tdomain_transport(aliasdata,local,default_target);
++    return netsnmp_tdomain_transport(aliasdata,local,default_target, iface);
+ }
+ 
+ 
+ 
+ netsnmp_transport *
+-netsnmp_alias_create_ostring(const u_char * o, size_t o_len, int local)
++netsnmp_alias_create_ostring(const u_char * o, size_t o_len, int local, char *iface)
+ {
+     fprintf(stderr, "make ostring\n");
+     return NULL;
+diff --git a/snmplib/transports/snmpTCPDomain.c b/snmplib/transports/snmpTCPDomain.c
+index 7feb028..6eb717e 100644
+--- a/snmplib/transports/snmpTCPDomain.c
++++ b/snmplib/transports/snmpTCPDomain.c
+@@ -144,7 +144,7 @@ netsnmp_tcp_accept(netsnmp_transport *t)
+  */
+ 
+ netsnmp_transport *
+-netsnmp_tcp_transport(struct sockaddr_in *addr, int local)
++netsnmp_tcp_transport(struct sockaddr_in *addr, int local, char *iface)
+ {
+     netsnmp_transport *t = NULL;
+     netsnmp_udp_addr_pair *addr_pair = NULL;
+@@ -212,6 +212,11 @@ netsnmp_tcp_transport(struct sockaddr_in *addr, int local)
+          * We should set SO_REUSEADDR too.  
+          */
+ 
++        if (iface && setsockopt(t->sock, SOL_SOCKET, SO_BINDTODEVICE,
++                                iface, strlen(iface)) == -1)
++                snmp_log(LOG_ERR, "Bind interface %s to socket: %s\n",
++                                iface, strerror(errno));
++
+         setsockopt(t->sock, SOL_SOCKET, SO_REUSEADDR, (void *)&opt,
+ 		   sizeof(opt));
+ 
+@@ -305,12 +310,13 @@ netsnmp_tcp_transport(struct sockaddr_in *addr, int local)
+ 
+ netsnmp_transport *
+ netsnmp_tcp_create_tstring(const char *str, int local,
+-			   const char *default_target)
++			   const char *default_target,
++			   char *iface)
+ {
+     struct sockaddr_in addr;
+ 
+     if (netsnmp_sockaddr_in2(&addr, str, default_target)) {
+-        return netsnmp_tcp_transport(&addr, local);
++        return netsnmp_tcp_transport(&addr, local, iface);
+     } else {
+         return NULL;
+     }
+@@ -319,7 +325,7 @@ netsnmp_tcp_create_tstring(const char *str, int local,
+ 
+ 
+ netsnmp_transport *
+-netsnmp_tcp_create_ostring(const u_char * o, size_t o_len, int local)
++netsnmp_tcp_create_ostring(const u_char * o, size_t o_len, int local, char *iface)
+ {
+     struct sockaddr_in addr;
+ 
+@@ -328,7 +334,7 @@ netsnmp_tcp_create_ostring(const u_char * o, size_t o_len, int local)
+         addr.sin_family = AF_INET;
+         memcpy((u_char *) & (addr.sin_addr.s_addr), o, 4);
+         addr.sin_port = htons(porttmp);
+-        return netsnmp_tcp_transport(&addr, local);
++        return netsnmp_tcp_transport(&addr, local, iface);
+     }
+     return NULL;
+ }
+diff --git a/snmplib/transports/snmpUDPBaseDomain.c b/snmplib/transports/snmpUDPBaseDomain.c
+index 8497f71..7b415bc 100644
+--- a/snmplib/transports/snmpUDPBaseDomain.c
++++ b/snmplib/transports/snmpUDPBaseDomain.c
+@@ -21,6 +21,9 @@
+ #if HAVE_NETINET_IN_H
+ #include <netinet/in.h>
+ #endif
++#if HAVE_NET_IF_H
++#include <net/if.h>
++#endif
+ #if HAVE_ARPA_INET_H
+ #include <arpa/inet.h>
+ #endif
+@@ -53,8 +56,14 @@
+ #endif
+ 
+ void
+-_netsnmp_udp_sockopt_set(int fd, int local)
++_netsnmp_udp_sockopt_set(int fd, int local, char *iface)
+ {
++
++    if (iface && setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, iface, strlen(iface)) == -1)
++        snmp_log(LOG_ERR, "Bind socket on interface: %s: %s\n", iface, strerror(errno));
++    else if (iface)
++        DEBUGMSGTL(("socket:option", "setting SO_BINDTODEVICE to %s\n", iface));
++
+ #ifdef  SO_BSDCOMPAT
+     /*
+      * Patch for Linux.  Without this, UDP packets that fail get an ICMP
+@@ -237,7 +246,10 @@ int netsnmp_udpbase_sendto(int fd, struct in_addr *srcip, int if_index,
+     struct msghdr m = { 0 };
+     char          cmsg[CMSG_SPACE(cmsg_data_size)];
+     int           rc;
+-
++    char          iface[IFNAMSIZ];
++    socklen_t     ifacelen = IFNAMSIZ;
++ 
++    iface[0] = '\0';
+     iov.iov_base = data;
+     iov.iov_len  = len;
+ 
+@@ -269,14 +281,23 @@ int netsnmp_udpbase_sendto(int fd, struct in_addr *srcip, int if_index,
+ 
+             memset(&ipi, 0, sizeof(ipi));
+             /*
+-             * Except in the case of responding
+-             * to a broadcast, setting the ifindex
+-             * when responding results in incorrect
+-             * behavior of changing the source address
+-             * that the manager sees the response
+-             * come from.
++             * For asymmetric multihomed users, we only set ifindex to 0
++             * to let kernel handle return if there was no iface bound to the socket.
+              */
+-            ipi.ipi_ifindex = 0;
++            if (getsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, iface, &ifacelen) != 0)  {
++                DEBUGMSGTL(("socket:option", "error getsockopt %s\n", strerror(errno)));
++                DEBUGMSGTL(("socket:option", "sendto: SO_BINDTODEVICE not set ifindex=0\n"));
++                ipi.ipi_ifindex = 0;
++            } else if (!ifacelen) {
++                DEBUGMSGTL(("socket:option", "sendto: SO_BINDTODEVICE not set ifacelen=%d ifindex=0\n",
++                            ifacelen));
++                ipi.ipi_ifindex = 0;
++            } else {
++                DEBUGMSGTL(("socket:option", "sendto: SO_BINDTODEVICE dev=%s using ifindex=%d\n",
++                            iface, if_index));
++                ipi.ipi_ifindex = if_index;
++            }
++
+ #if defined(cygwin)
+             ipi.ipi_addr.s_addr = srcip->s_addr;
+ #else
+diff --git a/snmplib/transports/snmpUDPDomain.c b/snmplib/transports/snmpUDPDomain.c
+index a0abd8c..fc68303 100644
+--- a/snmplib/transports/snmpUDPDomain.c
++++ b/snmplib/transports/snmpUDPDomain.c
+@@ -84,7 +84,7 @@ typedef netsnmp_indexed_addr_pair netsnmp_udp_addr_pair;
+  * not static, since snmpUDPIPv6Domain needs it, but not public, either.
+  * (ie don't put it in a public header.)
+  */
+-void _netsnmp_udp_sockopt_set(int fd, int server);
++void _netsnmp_udp_sockopt_set(int fd, int server, char *iface);
+ int
+ netsnmp_sockaddr_in2(struct sockaddr_in *addr,
+                      const char *inpeername, const char *default_target);
+@@ -125,11 +125,11 @@ int netsnmp_udp_sendto(int fd, struct in_addr *srcip, int if_index, struct socka
+  */
+ 
+ netsnmp_transport *
+-netsnmp_udp_transport(struct sockaddr_in *addr, int local)
++netsnmp_udp_transport(struct sockaddr_in *addr, int local, char *iface)
+ {
+     netsnmp_transport *t = NULL;
+ 
+-    t = netsnmp_udpipv4base_transport(addr, local);
++    t = netsnmp_udpipv4base_transport(addr, local, iface);
+     if (NULL == t) {
+         return NULL;
+     }
+@@ -473,12 +473,13 @@ netsnmp_udp_getSecName(void *opaque, int olength,
+ 
+ netsnmp_transport *
+ netsnmp_udp_create_tstring(const char *str, int local,
+-			   const char *default_target)
++			   const char *default_target,
++			   char *iface)
+ {
+     struct sockaddr_in addr;
+ 
+     if (netsnmp_sockaddr_in2(&addr, str, default_target)) {
+-        return netsnmp_udp_transport(&addr, local);
++        return netsnmp_udp_transport(&addr, local, iface);
+     } else {
+         return NULL;
+     }
+@@ -486,7 +487,7 @@ netsnmp_udp_create_tstring(const char *str, int local,
+ 
+ 
+ netsnmp_transport *
+-netsnmp_udp_create_ostring(const u_char * o, size_t o_len, int local)
++netsnmp_udp_create_ostring(const u_char * o, size_t o_len, int local, char *iface)
+ {
+     struct sockaddr_in addr;
+ 
+@@ -495,7 +496,7 @@ netsnmp_udp_create_ostring(const u_char * o, size_t o_len, int local)
+         addr.sin_family = AF_INET;
+         memcpy((u_char *) & (addr.sin_addr.s_addr), o, 4);
+         addr.sin_port = htons(porttmp);
+-        return netsnmp_udp_transport(&addr, local);
++        return netsnmp_udp_transport(&addr, local, iface);
+     }
+     return NULL;
+ }
+diff --git a/snmplib/transports/snmpUDPIPv4BaseDomain.c b/snmplib/transports/snmpUDPIPv4BaseDomain.c
+index 8c0fb05..7991b6a 100644
+--- a/snmplib/transports/snmpUDPIPv4BaseDomain.c
++++ b/snmplib/transports/snmpUDPIPv4BaseDomain.c
+@@ -57,7 +57,7 @@ int netsnmp_udpipv4_sendto(int fd, struct in_addr *srcip, int if_index,
+ #endif /* HAVE_IP_PKTINFO || HAVE_IP_RECVDSTADDR */
+ 
+ netsnmp_transport *
+-netsnmp_udpipv4base_transport(struct sockaddr_in *addr, int local)
++netsnmp_udpipv4base_transport(struct sockaddr_in *addr, int local, char *iface)
+ {
+     netsnmp_transport *t = NULL;
+     int             rc = 0, rc2;
+@@ -95,7 +95,7 @@ netsnmp_udpipv4base_transport(struct sockaddr_in *addr, int local)
+         return NULL;
+     }
+ 
+-    _netsnmp_udp_sockopt_set(t->sock, local);
++    _netsnmp_udp_sockopt_set(t->sock, local, iface);
+ 
+     if (local) {
+ #ifndef NETSNMP_NO_LISTEN_SUPPORT
+diff --git a/snmplib/transports/snmpUDPIPv6Domain.c b/snmplib/transports/snmpUDPIPv6Domain.c
+index 18de876..6b44b22 100644
+--- a/snmplib/transports/snmpUDPIPv6Domain.c
++++ b/snmplib/transports/snmpUDPIPv6Domain.c
+@@ -186,7 +186,7 @@ netsnmp_udp6_send(netsnmp_transport *t, void *buf, int size,
+  */
+ 
+ netsnmp_transport *
+-netsnmp_udp6_transport(struct sockaddr_in6 *addr, int local)
++netsnmp_udp6_transport(struct sockaddr_in6 *addr, int local, char *iface)
+ {
+     netsnmp_transport *t = NULL;
+     int             rc = 0;
+@@ -223,7 +223,7 @@ netsnmp_udp6_transport(struct sockaddr_in6 *addr, int local)
+         return NULL;
+     }
+ 
+-    _netsnmp_udp_sockopt_set(t->sock, local);
++    _netsnmp_udp_sockopt_set(t->sock, local, iface);
+ 
+     if (local) {
+ #ifndef NETSNMP_NO_LISTEN_SUPPORT
+@@ -724,12 +724,13 @@ netsnmp_udp6_getSecName(void *opaque, int olength,
+ 
+ netsnmp_transport *
+ netsnmp_udp6_create_tstring(const char *str, int local,
+-			    const char *default_target)
++			    const char *default_target,
++			    char *iface)
+ {
+     struct sockaddr_in6 addr;
+ 
+     if (netsnmp_sockaddr_in6_2(&addr, str, default_target)) {
+-        return netsnmp_udp6_transport(&addr, local);
++        return netsnmp_udp6_transport(&addr, local, iface);
+     } else {
+         return NULL;
+     }
+@@ -746,7 +747,7 @@ netsnmp_udp6_create_tstring(const char *str, int local,
+  */
+ 
+ netsnmp_transport *
+-netsnmp_udp6_create_ostring(const u_char * o, size_t o_len, int local)
++netsnmp_udp6_create_ostring(const u_char * o, size_t o_len, int local, char *iface)
+ {
+     struct sockaddr_in6 addr;
+ 
+@@ -755,7 +756,7 @@ netsnmp_udp6_create_ostring(const u_char * o, size_t o_len, int local)
+         addr.sin6_family = AF_INET6;
+         memcpy((u_char *) & (addr.sin6_addr.s6_addr), o, 16);
+         addr.sin6_port = htons((o[16] << 8) + o[17]);
+-        return netsnmp_udp6_transport(&addr, local);
++        return netsnmp_udp6_transport(&addr, local, iface);
+     }
+     return NULL;
+ }
+diff --git a/snmplib/transports/snmpUnixDomain.c b/snmplib/transports/snmpUnixDomain.c
+index 47dffc1..af56c5d 100644
+--- a/snmplib/transports/snmpUnixDomain.c
++++ b/snmplib/transports/snmpUnixDomain.c
+@@ -450,7 +450,8 @@ netsnmp_unix_transport(struct sockaddr_un *addr, int local)
+ 
+ netsnmp_transport *
+ netsnmp_unix_create_tstring(const char *string, int local,
+-			    const char *default_target)
++			    const char *default_target,
++			    char *iface)
+ {
+     struct sockaddr_un addr;
+ 
+@@ -476,7 +477,7 @@ netsnmp_unix_create_tstring(const char *string, int local,
+ 
+ 
+ netsnmp_transport *
+-netsnmp_unix_create_ostring(const u_char * o, size_t o_len, int local)
++netsnmp_unix_create_ostring(const u_char * o, size_t o_len, int local, char *iface)
+ {
+     struct sockaddr_un addr;
+ 
+-- 
+2.7.4
+

src/snmpd/patch-5.7.3+dfsg/series

@@ -4,3 +4,4 @@
 0004-Disable-SNMPv1.patch
 0005-Port-OpenSSL-1.1.0-with-support-for-1.0.2.patch
 0006-From-Jiri-Cervenka-snmpd-Fixed-agentx-crashing-and-or-freezing-on-timeout.patch
+0007-Linux-VRF-5.7.3-Support.patch