Fix compile_filter on *BSD with non-ether linktypes (#4670)

* Fix compile_filter on *BSD with non-ether linktypes

* Populate iface.type on the *BSDs

* Fix IEEE802 ARP->DLT

Author: gpotter2

scapy/arch/bpf/pfroute.py

@@ -1234,11 +1234,13 @@ def _get_if_list():
         ifindex = msg.ifm_index
         ifname = None
         mac = "00:00:00:00:00:00"
+        itype = -1
         ifflags = msg.ifm_flags
         ips = []
         for addr in msg.addrs:
             if addr.sa_family == socket.AF_LINK:
                 ifname = addr.sdl_iface.decode()
+                itype = addr.sdl_type
                 if addr.sdl_addr:
                     mac = addr.sdl_addr
         if ifname is not None:
@@ -1250,5 +1252,6 @@ def _get_if_list():
                 "flags": ifflags,
                 "mac": mac,
                 "ips": ips,
+                "type": itype,
             }
     return interfaces

scapy/arch/common.py

@@ -12,7 +12,7 @@
 import socket
 
 from scapy.config import conf
-from scapy.data import MTU, ARPHDR_ETHER, ARPHRD_TO_DLT
+from scapy.data import MTU, ARPHRD_TO_DLT
 from scapy.error import Scapy_Exception, warning
 from scapy.interfaces import network_name, resolve_iface, NetworkInterface
 from scapy.libs.structures import bpf_program
@@ -105,8 +105,6 @@ def compile_filter(filter_exp,  # type: str
         except Exception:
             # Failed to use linktype: use the interface
             pass
-        if not linktype and conf.use_bpf:
-            linktype = ARPHDR_ETHER
     if linktype is not None:
         ret = pcap_compile_nopcap(
             MTU, linktype, ctypes.byref(bpf), bpf_filter, 1, -1

scapy/data.py

@@ -202,7 +202,7 @@
     ARPHRD_CHAOS: DLT_CHAOS,
     ARPHRD_CAN: DLT_LINUX_SLL,
     ARPHRD_IEEE802_TR: DLT_IEEE802,
-    ARPHRD_IEEE802: DLT_IEEE802,
+    ARPHRD_IEEE802: DLT_EN10MB,
     ARPHRD_ARCNET: DLT_ARCNET_LINUX,
     ARPHRD_FDDI: DLT_FDDI,
     ARPHRD_ATM: -1,