[bgp-scale-test] Use different icmp type for each traffic thread to remove packet count noise (sonic-net#19380)

What is the motivation for this PR?
We run test cases one by one, however, when count packets in next test case, it may count some packets from previous test case.

How did you do it?
To remove the noise, we use different icmp type for each traffic thread in test case, so that the packet count is more accurate.

How did you verify/test it?
Run test on 5640 testbed with 510 bgp session

Author: w1nda

tests/bgp/test_ipv6_bgp_scale.py

@@ -42,18 +42,16 @@
 PACKETS_PER_TIME_SLOT = 500 // PKTS_SENDING_TIME_SLOT
 MASK_COUNTER_WAIT_TIME = 10  # wait some seconds for mask counters processing packets
 STATIC_ROUTES = ['0.0.0.0/0', '::/0']
-ICMP_TYPE = 123
 WITHDRAW_ROUTE_NUMBER = 1
+global_icmp_type = 123
 
 
-@pytest.fixture(scope="module")
-def setup_packet_mask_counters(ptfadapter):
+def setup_packet_mask_counters(ptf_dataplane, icmp_type):
     """
     Create a mask counters for packet sending
     """
-    ptf_dp = ptfadapter.dataplane
     exp_pkt = simple_icmpv6_packet(
-        icmp_type=ICMP_TYPE
+        icmp_type=icmp_type
     )
     masked_exp_pkt = Mask(exp_pkt)
     masked_exp_pkt.set_do_not_care_scapy(scapy.Ether, 'src')
@@ -62,9 +60,9 @@ def setup_packet_mask_counters(ptfadapter):
     masked_exp_pkt.set_do_not_care_scapy(scapy.IPv6, "dst")
     masked_exp_pkt.set_do_not_care_scapy(scapy.IPv6, "hlim")
     masked_exp_pkt.set_do_not_care_scapy(scapy.ICMPv6Unknown, "cksum")
-    ptf_dp.create_mask_counters(masked_exp_pkt)
+    ptf_dataplane.create_mask_counters(masked_exp_pkt)
 
-    yield masked_exp_pkt
+    return masked_exp_pkt
 
 
 @pytest.fixture(scope="function")
@@ -152,7 +150,7 @@ def generate_packets(prefixes, dut_mac, src_mac):
             eth_dst=dut_mac,
             eth_src=src_mac,
             ipv6_dst=addr,
-            icmp_type=ICMP_TYPE
+            icmp_type=global_icmp_type
         )
         pkts.append(bytes(pkt))
 
@@ -328,7 +326,6 @@ def test_sessions_flapping(
     ptfadapter,
     bgp_peers_info,
     flapping_port_count,
-    setup_packet_mask_counters,
     announce_bgp_routes_teardown
 ):
     '''
@@ -343,8 +340,10 @@ def test_sessions_flapping(
     Expected result:
         Dataplane downtime is less than MAX_DOWNTIME_ONE_PORT_FLAPPING.
     '''
+    global global_icmp_type
+    global_icmp_type += 1
     pdp = ptfadapter.dataplane
-    exp_mask = setup_packet_mask_counters
+    exp_mask = setup_packet_mask_counters(pdp, global_icmp_type)
     bgp_neighbors = [hostname for hostname in bgp_peers_info.keys()]
 
     random.shuffle(bgp_neighbors)
@@ -404,7 +403,6 @@ def test_nexthop_group_member_scale(
     localhost,
     tbinfo,
     bgp_peers_info,
-    setup_packet_mask_counters,
     announce_bgp_routes_teardown,
     request
 ):
@@ -424,11 +422,10 @@ def test_nexthop_group_member_scale(
     '''
     servers_dut_interfaces = announce_bgp_routes_teardown
     topo_name = tbinfo['topo']['name']
-    if 't1' in topo_name:
-        pytest.skip("Skip test on T1 topology because every route only have one nexthop")
-
+    global global_icmp_type
+    global_icmp_type += 1
     pdp = ptfadapter.dataplane
-    exp_mask = setup_packet_mask_counters
+    exp_mask = setup_packet_mask_counters(pdp, global_icmp_type)
     injection_bgp_neighbor = random.choice(list(bgp_peers_info.keys()))
     injection_dut_port = bgp_peers_info[injection_bgp_neighbor][DUT_PORT]
     injection_port = [i[PTF_PORT] for i in bgp_peers_info.values() if i[DUT_PORT] == injection_dut_port][0]
@@ -492,6 +489,13 @@ def test_nexthop_group_member_scale(
         pytest.fail("BGP routes are not stable in long time")
 
     # ------------announce routes and test ------------ #
+    global_icmp_type += 1
+    exp_mask = setup_packet_mask_counters(pdp, global_icmp_type)
+    pkts = generate_packets(
+        neighbor_ecmp_routes[injection_bgp_neighbor],
+        duthost.facts['router_mac'],
+        pdp.get_mac(pdp.port_to_device(injection_port), injection_port)
+    )
     terminated = Event()
     traffic_thread = Thread(
         target=send_packets, args=(terminated, pdp, pdp.port_to_device(injection_port), injection_port, pkts)
@@ -516,7 +520,6 @@ def test_device_unisolation(
     duthost,
     ptfadapter,
     bgp_peers_info,
-    setup_packet_mask_counters,
     announce_bgp_routes_teardown,
     tbinfo
 ):
@@ -533,8 +536,10 @@ def test_device_unisolation(
     Expected result:
         Dataplane downtime is less than MAX_DOWNTIME_UNISOLATION.
     '''
+    global global_icmp_type
+    global_icmp_type += 1
     pdp = ptfadapter.dataplane
-    exp_mask = setup_packet_mask_counters
+    exp_mask = setup_packet_mask_counters(pdp, global_icmp_type)
 
     bgp_ports = [bgp_info[DUT_PORT] for bgp_info in bgp_peers_info.values()]