Check route redistribution for static routes (#3633)

What is the motivation for this PR?
The static routes applied to CONFIG_DB are supposed to get redistributed to the BGP neighbors. The motivation of the PR is to check if the static routes get properly redistributed.

How did you do it?
Check route advertised to BGP neighbor after configuring static routes.

tests/route/test_static_route.py

@@ -4,6 +4,7 @@
 import time
 import natsort
 import random
+import re
 
 from tests.common.dualtor.dual_tor_utils import mux_cable_server_ip
 from tests.common.dualtor.dual_tor_utils import get_t1_ptf_ports
@@ -87,6 +88,33 @@ def generate_and_verify_traffic(duthost, ptfadapter, tbinfo, ip_dst, expected_po
     testutils.verify_packet_any_port(ptfadapter, exp_pkt, ports=expected_ports)
 
 
+def check_route_redistribution(duthost, prefix, ipv6, removed=False):
+    if ipv6:
+        bgp_neighbor_addr_regex = re.compile(r"^([0-9a-fA-F]{1,4}:[0-9a-fA-F:]+)")
+        SHOW_BGP_SUMMARY_CMD = "show ipv6 bgp summary"
+        SHOW_BGP_ADV_ROUTES_CMD_TEMPLATE = "show ipv6 bgp neighbor {} advertised-routes"
+    else:
+        bgp_neighbor_addr_regex = re.compile(r"^([0-9]{1,3}\.){3}[0-9]{1,3}")
+        SHOW_BGP_SUMMARY_CMD = "show ip bgp summary"
+        SHOW_BGP_ADV_ROUTES_CMD_TEMPLATE = "show ip bgp neighbor {} advertised-routes"
+
+    bgp_summary = duthost.shell(SHOW_BGP_SUMMARY_CMD)["stdout"].split("\n")
+
+    bgp_neighbors = []
+
+    for line in bgp_summary:
+        matched = bgp_neighbor_addr_regex.match(line)
+        if matched:
+            bgp_neighbors.append(str(matched.group(0)))
+
+    for neighbor in bgp_neighbors:
+        adv_routes = duthost.shell(SHOW_BGP_ADV_ROUTES_CMD_TEMPLATE.format(neighbor))["stdout"]
+        if removed:
+            assert prefix not in adv_routes
+        else:
+            assert prefix in adv_routes
+
+
 def run_static_route_test(duthost, ptfadapter, ptfhost, tbinfo, prefix, nexthop_addrs, prefix_len, nexthop_devs, ipv6=False, config_reload_test=False):
     # Add ipaddresses in ptf
     add_ipaddr(ptfhost, nexthop_addrs, prefix_len, nexthop_devs, ipv6=ipv6)
@@ -100,11 +128,15 @@ def run_static_route_test(duthost, ptfadapter, ptfhost, tbinfo, prefix, nexthop_
         ip_dst = str(ipaddress.ip_network(unicode(prefix))[1])
         generate_and_verify_traffic(duthost, ptfadapter, tbinfo, ip_dst, nexthop_devs, ipv6=ipv6)
 
+        # Check the route is advertised to the neighbors
+        check_route_redistribution(duthost, prefix, ipv6)
+
         # Config save and reload if specified
         if config_reload_test:
             duthost.shell('config save -y')
             config_reload(duthost)
             generate_and_verify_traffic(duthost, ptfadapter, tbinfo, ip_dst, nexthop_devs, ipv6=ipv6)
+            check_route_redistribution(duthost, prefix, ipv6)
 
     finally:
         # Remove static route
@@ -113,6 +145,10 @@ def run_static_route_test(duthost, ptfadapter, ptfhost, tbinfo, prefix, nexthop_
         # Delete ipaddresses in ptf
         del_ipaddr(ptfhost, nexthop_addrs, prefix_len, nexthop_devs, ipv6=ipv6)
 
+        # Check the advertised route get removed
+        time.sleep(5)
+        check_route_redistribution(duthost, prefix, ipv6, removed=True)
+
         # Config save if the saved config_db was updated
         if config_reload_test:
             duthost.shell('config save -y')