Merge pull request #129 from guedou/SCAPY_USE_PCAPDNET

Introducing the SCAPY_USE_PCAPDNET environment variable

scapy/config.py

@@ -363,8 +363,8 @@ extensions_paths: path or list of paths where extensions are to be looked for
     resolve = Resolve()
     noenum = Resolve()
     emph = Emphasize()
-    use_pcap = False
-    use_dnet = False
+    use_pcap = os.getenv("SCAPY_USE_PCAPDNET", "").lower().startswith("y")
+    use_dnet = os.getenv("SCAPY_USE_PCAPDNET", "").lower().startswith("y")
     use_winpcapy = False
     ipv6_enabled = socket.has_ipv6
     ethertypes = ETHER_TYPES