fix(tests): add backplane port only in srv6 tests (sonic-net#16669)

What is the motivation for this PR?
Backplane port is necessary in our srv6 tests, but it will cause random failure in other tests. When the test packet dst IP matches the IP prefix advertised by the exabgp, the ptf backplane interface will receive the test packet from the neighbor VM. The reason is the routes are advertised by exabgp to VM through the ptf backplane interface. And methods like verify_packet_any_port() not only validate the packet is received by the expected ports, but also validate it's not received by the unexpected ports.

How did you do it?
Added configuration options in ptf initial to limite the configuration scenarios of backplane ports only in srv6 tests

How did you verify/test it?
we tested it via daily jenkins run

Signed-off-by: linsongnan <linsongnan.lsn@alibaba-inc.com>

Author: LARLSN

ansible/roles/test/files/ptftests/remote.py

@@ -34,7 +34,7 @@ def get_ifaces():
     return ifaces
 
 
-def build_ifaces_map(ifaces):
+def build_ifaces_map(ifaces, ptf_config=None):
     """Build interface map for ptf to init dataplane."""
     ptf_port_mapping_mode = "use_orig_interface"
     constants_file = os.path.join(os.path.dirname(__file__), "constants.yaml")
@@ -44,6 +44,10 @@ def build_ifaces_map(ifaces):
             ptf_port_mapping_mode = constants.get(
                 "PTF_PORT_MAPPING_MODE", ptf_port_mapping_mode)
 
+    need_backplane = False
+    if ptf_config is not None and 'need_backplane' in ptf_config:
+        need_backplane = ptf_config['need_backplane']
+
     sub_ifaces = []
     iface_map = {}
     used_index = set()
@@ -63,7 +67,7 @@ def build_ifaces_map(ifaces):
     count = 1
     while count in used_index:
         count = count + 1
-    if backplane_exist:
+    if backplane_exist and need_backplane:
         iface_map[(0, count)] = "backplane"
 
     if ptf_port_mapping_mode == "use_sub_interface":
@@ -85,6 +89,6 @@ def platform_config_update(config):
     @param config The configuration dictionary to use/update
     """
 
-    remote_port_map = build_ifaces_map(get_ifaces())
+    remote_port_map = build_ifaces_map(get_ifaces(), config)
     config["port_map"] = remote_port_map.copy()
     config["caps_table_idx"] = 0

tests/common/plugins/ptfadapter/__init__.py

@@ -74,7 +74,7 @@ def get_ifaces(netdev_output):
     return ifaces
 
 
-def get_ifaces_map(ifaces, ptf_port_mapping_mode):
+def get_ifaces_map(ifaces, ptf_port_mapping_mode, need_backplane=False):
     """Get interface map."""
     sub_ifaces = []
     iface_map = {}
@@ -95,7 +95,7 @@ def get_ifaces_map(ifaces, ptf_port_mapping_mode):
     count = 1
     while count in used_index:
         count = count + 1
-    if backplane_exist:
+    if backplane_exist and need_backplane:
         iface_map[count] = "backplane"
 
     if ptf_port_mapping_mode == "use_sub_interface":
@@ -125,10 +125,14 @@ def ptfadapter(ptfhost, tbinfo, request, duthost):
     else:
         ptf_port_mapping_mode = 'use_orig_interface'
 
+    need_backplane = False
+    if 'ciscovs-7nodes' in tbinfo['topo']['name']:
+        need_backplane = True
+
     # get the eth interfaces from PTF and initialize ifaces_map
     res = ptfhost.command('cat /proc/net/dev')
     ifaces = get_ifaces(res['stdout'])
-    ifaces_map = get_ifaces_map(ifaces, ptf_port_mapping_mode)
+    ifaces_map = get_ifaces_map(ifaces, ptf_port_mapping_mode, need_backplane)
 
     def start_ptf_nn_agent():
         for i in range(MAX_RETRY_TIME):

tests/iface_loopback_action/conftest.py

@@ -61,9 +61,14 @@ def orig_ports_configuration(request, duthost, ptfhost, tbinfo):
                                         constants.PTF_PORT_MAPPING_MODE_DEFAULT)
     else:
         ptf_port_mapping_mode = 'use_orig_interface'
+
+    need_backplane = False
+    if 'ciscovs-7nodes' in tbinfo['topo']['name']:
+        need_backplane = True
+
     res = ptfhost.command('cat /proc/net/dev')
     ptf_ifaces = get_ifaces(res['stdout'])
-    ptf_ifaces_map = get_ifaces_map(ptf_ifaces, ptf_port_mapping_mode)
+    ptf_ifaces_map = get_ifaces_map(ptf_ifaces, ptf_port_mapping_mode, need_backplane)
     port_dict = get_tested_up_ports(duthost, ptf_ifaces_map, count=PORT_COUNT)
     yield port_dict
 

tests/srv6/test_srv6_basic_sanity.py

@@ -80,7 +80,11 @@
 #
 # Initialize the testbed
 #
-def setup_config(duthosts, rand_one_dut_hostname, nbrhosts, ptfhost):
+def setup_config(duthosts, rand_one_dut_hostname, nbrhosts, ptfhost, ptfadapter):
+
+    logger.info("reinit ptfadapter")
+    ptfadapter.reinit({'need_backplane': True})
+
     logger.info("Announce routes from CEs")
     ptfip = ptfhost.mgmt_ip
     nexthop = "10.10.246.254"
@@ -116,8 +120,8 @@ def setup_config(duthosts, rand_one_dut_hostname, nbrhosts, ptfhost):
 # Testbed set up and tear down
 #
 @pytest.fixture(scope="module", autouse=True)
-def srv6_config(duthosts, rand_one_dut_hostname, nbrhosts, ptfhost):
-    setup_config(duthosts, rand_one_dut_hostname, nbrhosts, ptfhost)
+def srv6_config(duthosts, rand_one_dut_hostname, nbrhosts, ptfhost, ptfadapter):
+    setup_config(duthosts, rand_one_dut_hostname, nbrhosts, ptfhost, ptfadapter)
 
 
 #