[dualtor-io] fix dualtor sniffer start slow issue (sonic-net#18758)

Signed-off-by: Longxiang Lyu <lolv@microsoft.com>

Author: lolyu

tests/scripts/dual_tor_sniffer.py

@@ -5,9 +5,19 @@
 import scapy.all as scapyall
 
 
+class L2ListenAllSocket(scapyall.conf.L2listen):
+    """Read packets at layer2 using Linux PF_PACKET sockets on all ports."""
+
+    def __init__(self, *args, **kwargs):
+        # HACK: Set the socket bind to NOOP, so the packet sockets created
+        # will not bind to any interface and it will listen on all interfaces
+        # by default.
+        socket.bind = lambda _: None
+        super(L2ListenAllSocket, self).__init__(*args, **kwargs)
+
+
 class Sniffer(object):
     def __init__(self, filter=None, timeout=60):
-        self.ifaces = [iface for _, iface in socket.if_nameindex() if iface.startswith("eth")]
         self.filter = filter
         self.timeout = timeout
         self.packets = []
@@ -17,7 +27,7 @@ def sniff(self):
         logging.debug("scapy sniffer started: filter={}, timeout={}".format(
             self.filter, self.timeout))
         scapyall.sniff(
-            iface=self.ifaces,
+            L2socket=L2ListenAllSocket,
             filter=self.filter,
             prn=self.process_pkt,
             timeout=self.timeout)