[FRR] Enable SNMP support (#2981)

This is a follow-up of sonic-snmpagent PR 92
Now that licensing issues have been solved FRR is distributed with SNMP
support compiled-in. This PR adds the last bits of configuration to get
the frr-snmp debian packages added to the docker container and the
config bits to enable the snmp module in FRR

This PR brings the functionality of being able to poll bgpd for routes
and peer status.

Signed-off-by: Michel Moriniaux <m.moriniaux@criteo.com>

dockers/docker-fpm-frr/Dockerfile.j2

@@ -41,5 +41,6 @@ RUN rm -rf /debs ~/.cache
 COPY ["bgpcfgd", "start.sh", "/usr/bin/"]
 COPY ["*.j2", "/usr/share/sonic/templates/"]
 COPY ["supervisord.conf", "/etc/supervisor/conf.d/"]
+COPY ["snmp.conf", "/etc/snmp/frr.conf"]
 
 ENTRYPOINT ["/usr/bin/supervisord"]

dockers/docker-fpm-frr/bgpd.conf.j2

@@ -11,6 +11,7 @@ hostname {{ DEVICE_METADATA['localhost']['hostname'] }}
 password zebra
 log syslog informational
 log facility local4
+agentx
 ! enable password {# {{ en_passwd }} TODO: param needed #}
 {% endblock system_init %}
 !

dockers/docker-fpm-frr/frr.conf.j2

@@ -11,6 +11,7 @@ hostname {{ DEVICE_METADATA['localhost']['hostname'] }}
 password zebra
 log syslog informational
 log facility local4
+agentx
 ! enable password {# {{ en_passwd }} TODO: param needed #}
 {% endblock system_init %}
 !

dockers/docker-fpm-frr/snmp.conf

@@ -0,0 +1,7 @@
+# This line allows the FRR docker to speak with the snmp container
+# Make sure this line matches the one in the snmp docker
+#   snmp:/etc/snmp/snmpd.conf
+# To verify this works you need to have a valid bgp daemon running and configured
+# Check that a snmpwalk to 1.3.6.1.2.1.15 gives an output
+# Further verification: 1.3.6.1.2.1.15.2.0 = INTEGER: 65000 the returned value should be the confiugred ASN
+agentXSocket    tcp:localhost:3161

dockers/docker-fpm-frr/supervisord.conf

@@ -31,7 +31,7 @@ stdout_logfile=syslog
 stderr_logfile=syslog
 
 [program:zebra]
-command=/usr/lib/frr/zebra -A 127.0.0.1 -s 90000000 -M fpm
+command=/usr/lib/frr/zebra -A 127.0.0.1 -s 90000000 -M fpm -M snmp
 priority=4
 autostart=false
 autorestart=false
@@ -49,7 +49,7 @@ stdout_logfile=syslog
 stderr_logfile=syslog
 
 [program:bgpd]
-command=/usr/lib/frr/bgpd -A 127.0.0.1
+command=/usr/lib/frr/bgpd -A 127.0.0.1 -M snmp
 priority=5
 stopsignal=KILL
 autostart=false

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

@@ -118,6 +118,14 @@ load   12 10 5
 #
                                            #  Run as an AgentX master agent
 master          agentx
+# internal socket to allow extension to other docker containers
+# Currently the other container using this is docker-fpm-frr
+# make sure this line matches bgp:/etc/snmp/frr.conf 
+# please see testing procedure in the same file to verify this works
+# to verify the SNMP docker side look for the following string in the log file:
+# INFO snmp-subagent [ax_interface] INFO: Using agentx socket type tcp with path tcp:localhost:3161
+# INFO supervisord snmp-subagent INFO:ax_interface:Using agentx socket type tcp with path tcp:localhost:3161
+agentxsocket    tcp:localhost:3161
 
 #
 #  SysDescription pass-through

rules/docker-fpm-frr.mk

@@ -2,7 +2,7 @@
 
 DOCKER_FPM_FRR = docker-fpm-frr.gz
 $(DOCKER_FPM_FRR)_PATH = $(DOCKERS_PATH)/docker-fpm-frr
-$(DOCKER_FPM_FRR)_DEPENDS += $(FRR) $(SWSS) $(LIBYANG)
+$(DOCKER_FPM_FRR)_DEPENDS += $(FRR) $(FRR_SNMP) $(SWSS) $(LIBYANG)
 $(DOCKER_FPM_FRR)_LOAD_DOCKERS += $(DOCKER_CONFIG_ENGINE_STRETCH)
 SONIC_DOCKER_IMAGES += $(DOCKER_FPM_FRR)
 

rules/frr.mk

@@ -18,4 +18,10 @@ $(eval $(call add_derived_package,$(FRR),$(FRR_PYTHONTOOLS)))
 FRR_DBG = frr-dbgsym_$(FRR_VERSION)-sonic-$(FRR_SUBVERSION)_amd64.deb
 $(eval $(call add_derived_package,$(FRR),$(FRR_DBG)))
 
-export FRR FRR_PYTHONTOOLS FRR_DBG
+FRR_SNMP = frr-snmp_$(FRR_VERSION)-sonic-$(FRR_SUBVERSION)_amd64.deb
+$(eval $(call add_derived_package,$(FRR),$(FRR_SNMP)))
+
+FRR_SNMP_DBG = frr-snmp-dbgsym_$(FRR_VERSION)-sonic-$(FRR_SUBVERSION)_amd64.deb
+$(eval $(call add_derived_package,$(FRR),$(FRR_SNMP_DBG)))
+
+export FRR FRR_PYTHONTOOLS FRR_DBG FRR_SNMP FRR_SNMP_DBG

src/sonic-config-engine/tests/sample_output/frr.conf

@@ -8,6 +8,7 @@ hostname switch-t0
 password zebra
 log syslog informational
 log facility local4
+agentx
 ! enable password !
 ! Enable link-detect (default disabled)
 interface PortChannel01

src/sonic-frr/Makefile

@@ -3,7 +3,7 @@ SHELL = /bin/bash
 .SHELLFLAGS += -e
 
 MAIN_TARGET = $(FRR)
-DERIVED_TARGET = $(FRR_PYTHONTOOLS) $(FRR_DBG)
+DERIVED_TARGET = $(FRR_PYTHONTOOLS) $(FRR_DBG) $(FRR_SNMP) $(FRR_SNMP_DBG)
 
 $(addprefix $(DEST)/, $(MAIN_TARGET)): $(DEST)/% :
 	# Build the package