[multi-ASIC] util changes with the BGP_INTERNAL_NEIGHBOR table. (#5760)

- Why I did it
Update the routine is_bgp_session_internal() by checking the BGP_INTERNAL_NEIGHBOR table.
Additionally to address the review comment #5520 (comment)
Add timer settings as will in the internal session templates and keep it minimal as these sessions which will always be up.
Updates to the internal tests data + add all of it to template tests.

- How I did it
Updated the APIs and the template files.

- How to verify it
Verified the internal BGP sessions are displayed correctly with show commands with this API is_bgp_session_internal()

Author: judyjoseph

dockers/docker-fpm-frr/frr/bgpd/templates/internal/instance.conf.j2

@@ -3,6 +3,7 @@
 !
   neighbor {{ neighbor_addr }} remote-as {{ bgp_session['asn'] }}
   neighbor {{ neighbor_addr }} description {{ bgp_session['name'] }}
+  neighbor {{ neighbor_addr }} timers 3 10
 !
 {% if neighbor_addr | ipv4 %}
   address-family ipv4

src/sonic-bgpcfgd/tests/data/internal/instance.conf/result_back_v4.conf

@@ -3,8 +3,7 @@
 !
   neighbor 10.10.10.10 remote-as 555
   neighbor 10.10.10.10 description remote_peer
-  neighbor 10.10.10.10 timers 5 30
-  neighbor 10.10.10.10 shutdown
+  neighbor 10.10.10.10 timers 3 10
   address-family ipv4
     neighbor 10.10.10.10 peer-group INTERNAL_PEER_V4
     neighbor 10.10.10.10 route-map FROM_BGP_INTERNAL_PEER_V4 in

src/sonic-bgpcfgd/tests/data/internal/instance.conf/result_back_v6.conf

@@ -3,8 +3,7 @@
 !
   neighbor fc::10 remote-as 555
   neighbor fc::10 description remote_peer
-  neighbor fc::10 timers 5 30
-  neighbor fc::10 shutdown
+  neighbor fc::10 timers 3 10
   address-family ipv6
     neighbor fc::10 peer-group INTERNAL_PEER_V6
     neighbor fc::10 route-map FROM_BGP_INTERNAL_PEER_V6 in

src/sonic-bgpcfgd/tests/data/internal/instance.conf/result_front_v4.conf

@@ -3,8 +3,7 @@
 !
   neighbor 10.10.10.10 remote-as 555
   neighbor 10.10.10.10 description remote_peer
-  neighbor 10.10.10.10 timers 5 30
-  neighbor 10.10.10.10 shutdown
+  neighbor 10.10.10.10 timers 3 10
   address-family ipv4
     neighbor 10.10.10.10 peer-group INTERNAL_PEER_V4
     neighbor 10.10.10.10 next-hop-self force

src/sonic-bgpcfgd/tests/data/internal/instance.conf/result_front_v6.conf

@@ -3,8 +3,7 @@
 !
   neighbor fc::10 remote-as 555
   neighbor fc::10 description remote_peer
-  neighbor fc::10 timers 5 30
-  neighbor fc::10 shutdown
+  neighbor fc::10 timers 3 10
   address-family ipv6
     neighbor fc::10 peer-group INTERNAL_PEER_V6
     neighbor fc::10 next-hop-self force

src/sonic-bgpcfgd/tests/test_templates.py

@@ -104,6 +104,18 @@ def test_general_instance():
     test_data = load_tests("general", "instance.conf")
     run_tests("general_instance", *test_data)
 
+def test_internal_policies():
+    test_data = load_tests("internal", "policies.conf")
+    run_tests("internal_policies", *test_data)
+
+def test_internal_pg():
+    test_data = load_tests("internal", "peer-group.conf")
+    run_tests("internal_pg", *test_data)
+
+def test_internal_instance():
+    test_data = load_tests("internal", "instance.conf")
+    run_tests("internal_instance", *test_data)
+
 def test_dynamic_policies():
     test_data = load_tests("dynamic", "policies.conf")
     run_tests("dynamic_policies", *test_data)

src/sonic-py-common/sonic_py_common/multi_asic.py

@@ -21,6 +21,7 @@
 PORT_CHANNEL_CFG_DB_TABLE = 'PORTCHANNEL'
 PORT_CFG_DB_TABLE = 'PORT'
 BGP_NEIGH_CFG_DB_TABLE = 'BGP_NEIGHBOR'
+BGP_INTERNAL_NEIGH_CFG_DB_TABLE = 'BGP_INTERNAL_NEIGHBOR'
 NEIGH_DEVICE_METADATA_CFG_DB_TABLE = 'DEVICE_NEIGHBOR_METADATA'
 DEFAULT_NAMESPACE = ''
 PORT_ROLE = 'role'
@@ -387,20 +388,10 @@ def is_bgp_session_internal(bgp_neigh_ip, namespace=None):
     for ns in ns_list:
 
         config_db = connect_config_db_for_ns(ns)
-        bgp_sessions = config_db.get_table(BGP_NEIGH_CFG_DB_TABLE)
-        if bgp_neigh_ip not in bgp_sessions:
-            continue
-
-        bgp_neigh_name = bgp_sessions[bgp_neigh_ip]['name']
-        neighbor_metadata = config_db.get_table(
-            NEIGH_DEVICE_METADATA_CFG_DB_TABLE)
-
-        if ((neighbor_metadata) and
-            (neighbor_metadata[bgp_neigh_name]['type'].lower() ==
-             ASIC_NAME_PREFIX)):
+        bgp_sessions = config_db.get_table(BGP_INTERNAL_NEIGH_CFG_DB_TABLE)
+        if bgp_neigh_ip in bgp_sessions:
             return True
-        else:
-            return False
+
     return False
 
 def get_front_end_namespaces():