Fix WARNING about IPv46 (#4465)

Author: gpotter2

scapy/arch/linux/__init__.py

@@ -344,7 +344,7 @@ def send(self, x):
             sdto = (iff, conf.l3types.layer2num[type_x])
         if sn[3] in conf.l2types:
             ll = lambda x: conf.l2types.num2layer[sn[3]]() / x
-        if self.lvl == 3 and type_x != self.LL:
+        if self.lvl == 3 and not issubclass(self.LL, type_x):
             warning("Incompatible L3 types detected using %s instead of %s !",
                     type_x, self.LL)
             self.LL = type_x

scapy/layers/inet6.py

@@ -480,7 +480,7 @@ def answers(self, other):
             return self.payload.answers(other.payload)
 
 
-class IPv46(IP):
+class IPv46(IP, IPv6):
     """
     This class implements a dispatcher that is used to detect the IP version
     while parsing Raw IP pcap files.