[bgp-scale-test] Implement bgp scale test cases for sessions flapping, unisolation, nexthop group member change scenarios (sonic-net#16069)

What is the motivation for this PR?
With numerous BGP sessions holding a lot routes, any flapping on BGP sessions or routes cloud have more overhead on device, we need test cases to verify the functionality and estimate convergence time, we publish this test plan.

How did you do it?
Implement sessions flapping test, unisolation test and nexthop group member scale test

Signed-off-by: Guy Shemesh <[email protected]>

Author: w1nda

ansible/library/announce_routes.py

@@ -150,6 +150,7 @@ def read_topo(topo_name, path):
 
 
 def change_routes(action, ptf_ip, port, routes):
+    logging.debug("action = {}, ptf_ip = {}, port = {}, routes = {}".format(action, ptf_ip, port, routes))
     messages = []
     for prefix, nexthop, aspath in routes:
         if aspath:
@@ -1308,6 +1309,23 @@ def fib_dpu(topo, ptf_ip, action="announce"):
         change_routes(action, ptf_ip, port6, routes_v6)
 
 
+def adhoc_routes(topo, ptf_ip, peers_routes_to_change, action):
+    vms = topo['topology']['VMs']
+
+    for hostname, routes in peers_routes_to_change.items():
+        vm_offset = vms[hostname]['vm_offset']
+        port = IPV4_BASE_PORT + vm_offset
+        port6 = IPV6_BASE_PORT + vm_offset
+
+        ipv4_routes = [r for r in routes if '.' in r[0]]
+        if ipv4_routes:
+            change_routes(action, ptf_ip, port, ipv4_routes)
+
+        ipv6_routes = [r for r in routes if ':' in r[0]]
+        if ipv6_routes:
+            change_routes(action, ptf_ip, port6, ipv6_routes)
+
+
 def get_ipv4_routes(routes):
     return [r for r in routes if ipaddress.ip_network(UNICODE_TYPE(r[0])).version == 4]
 
@@ -1345,6 +1363,8 @@ def main():
                         default='announce', choices=["announce", "withdraw"]),
             path=dict(required=False, type='str', default=''),
             dut_interfaces=dict(required=False, type='str', default=''),
+            adhoc=dict(required=False, type='bool', default=False),
+            peers_routes_to_change=dict(required=False, type='dict', default={}),
             log_path=dict(required=False, type='str', default='')
         ),
         supports_check_mode=False)
@@ -1357,6 +1377,8 @@ def main():
     action = module.params['action']
     dut_interfaces = module.params['dut_interfaces']
     path = module.params['path']
+    adhoc = module.params['adhoc']
+    peers_routes_to_change = module.params['peers_routes_to_change']
 
     topo = read_topo(topo_name, path)
     if not topo:
@@ -1372,7 +1394,10 @@ def main():
     topo_type = get_topo_type(topo_name)
 
     try:
-        if topo_type == "t0":
+        if adhoc:
+            adhoc_routes(topo, ptf_ip, peers_routes_to_change, action)
+            module.exit_json(change=True)
+        elif topo_type == "t0":
             fib_t0(topo, ptf_ip, no_default_route=is_storage_backend, action=action)
             module.exit_json(changed=True)
         elif topo_type == "t1" or topo_type == "smartswitch-t1":