[dhcp_relay][telemetry] Fix incorrect client mac in dhcp_relay relate…

…d telemetry test (#16112)

What is the motivation for this PR?
Client mac of DHCP packets should be ptf interface mac rather than DUT interface mac

How did you do it?
Modify test case to use ptf interface mac

How did you verify/test it?
Run tests in m0/t0 topo

tests/telemetry/events/dhcp-relay_events.py

@@ -8,7 +8,7 @@
 from tests.common.helpers.assertions import pytest_assert as py_assert
 from tests.common.utilities import wait_until
 from run_events_test import run_test
-from event_utils import find_test_vlan, find_test_port_and_mac, create_dhcp_discover_packet
+from event_utils import find_test_vlan, find_test_client_port_and_mac, create_dhcp_discover_packet
 
 logger = logging.getLogger(__name__)
 tag = "sonic-events-dhcp-relay"
@@ -96,7 +96,7 @@ def send_dhcp_discover_packets(duthost, ptfadapter, packets_to_send=5, interval=
         # Send packets
 
         # results contains up to 5 tuples of member interfaces from vlan (port, mac address)
-        results = find_test_port_and_mac(duthost, member_interfaces, 5)
+        results = find_test_client_port_and_mac(ptfadapter, duthost, member_interfaces, 5)
 
         for i in range(packets_to_send):
             result = results[i % len(results)]

tests/telemetry/events/event_utils.py

@@ -144,19 +144,18 @@ def find_test_vlan(duthost):
     return {}
 
 
-def find_test_port_and_mac(duthost, members, count):
-    # Will return up to count many up ports with their port index and mac address
+def find_test_client_port_and_mac(ptfadapter, duthost, members, count):
+    # Will return up to count many up ports with their port index and mac address of ptf
     results = []
     interf_status = duthost.show_interface(command="status")['ansible_facts']['int_status']
     for member_interface in members:
         if len(results) == count:
             return results
         if interf_status[member_interface]['admin_state'] == "up":
-            mac = duthost.get_dut_iface_mac(member_interface)
             minigraph_info = duthost.minigraph_facts(host=duthost.hostname)['ansible_facts']
             port_index = minigraph_info['minigraph_port_indices'][member_interface]
-            if mac != "" and port_index != "":
-                results.append([int(port_index), mac])
+            if port_index != "":
+                results.append([int(port_index), ptfadapter.dataplane.get_mac(0, port_index).decode()])
     return results