Manual cherry-pick PR:Handle v6 only for mtu test#20824 (sonic-net#920)

run test for v4 or v6 only if exists.

Author: OriTrabelsi

ansible/roles/test/files/ptftests/py3/mtu_test.py

@@ -210,7 +210,23 @@ def runTest(self):
         """
 
         self.pktlen = self.testbed_mtu
-        self.check_icmp_mtu()
-        self.check_icmp_mtu(ipv4=False)
-        self.check_ip_mtu()
-        self.check_ip_mtu(ipv4=False)
+        ipv4_available = (
+            self.src_host_ip is not None
+            and self.src_router_ip is not None
+            and self.dst_host_ip is not None
+            )
+        ipv6_available = (
+            self.src_host_ipv6 is not None
+            and self.src_router_ipv6 is not None
+            and self.dst_host_ipv6 is not None
+            )
+        if not ipv4_available and not ipv6_available:
+            raise Exception("Neither IPv4 nor IPv6 addresses are available for MTU testing")
+        if ipv4_available:
+            logging.info("Running IPv4 MTU tests")
+            self.check_icmp_mtu()
+            self.check_ip_mtu()
+        if ipv6_available:
+            logging.info("Running IPv6 MTU tests")
+            self.check_icmp_mtu(ipv4=False)
+            self.check_ip_mtu(ipv4=False)

tests/ipfwd/test_mtu.py

@@ -28,14 +28,14 @@ def test_mtu(tbinfo, ptfhost, mtu, gather_facts):
                params={"testbed_type": testbed_type,
                        "router_mac": gather_facts['src_router_mac'],
                        "testbed_mtu": mtu,
-                       "src_host_ip": gather_facts['src_host_ipv4'],
-                       "src_router_ip": gather_facts['src_router_ipv4'],
-                       "dst_host_ip": gather_facts['dst_host_ipv4'],
-                       "src_host_ipv6": gather_facts['src_host_ipv6'],
-                       "src_router_ipv6": gather_facts['src_router_ipv6'],
-                       "dst_host_ipv6": gather_facts['dst_host_ipv6'],
-                       "src_ptf_port_list": gather_facts['src_port_ids'],
-                       "dst_ptf_port_list": gather_facts['dst_port_ids'],
+                       "src_host_ip": gather_facts.get('src_host_ipv4'),
+                       "src_router_ip": gather_facts.get('src_router_ipv4'),
+                       "dst_host_ip": gather_facts.get('dst_host_ipv4'),
+                       "src_host_ipv6": gather_facts.get('src_host_ipv6'),
+                       "src_router_ipv6": gather_facts.get('src_router_ipv6'),
+                       "dst_host_ipv6": gather_facts.get('dst_host_ipv6'),
+                       "src_ptf_port_list": gather_facts.get('src_port_ids'),
+                       "dst_ptf_port_list": gather_facts.get('dst_port_ids'),
                        "kvm_support": True
                        },
                log_file=log_file,