Allow L2pcapListenSocket.recv() to return None if where is no captured...

Allow L2pcapListenSocket.recv() to return None if where is no captured packets. Make sniff() to continue loop if received pkt is None (issue #74)

scapy/arch/pcapdnet.py

@@ -203,7 +203,7 @@ if conf.use_winpcapy:
           else:
               cls = conf.default_l2
               warning("Unable to guess datalink type (interface=%s linktype=%i). Using %s" % (self.iface, ll, cls.name))
-  
+
           pkt = None
           while pkt is None:
               pkt = self.ins.next()
@@ -438,23 +438,20 @@ if conf.use_pcap:
                     cls = conf.default_l2
                     warning("Unable to guess datalink type (interface=%s linktype=%i). Using %s" % (self.iface, ll, cls.name))
         
-                pkt = None
-                while pkt is None:
-                    pkt = self.ins.next()
-                    if pkt is not None:
-                        ts,pkt = pkt
-                    if scapy.arch.WINDOWS and pkt is None:
+                pkt = self.ins.next()
+                if scapy.arch.WINDOWS and pkt is None:
                         raise PcapTimeoutElapsed
-                
-                try:
-                    pkt = cls(pkt)
-                except KeyboardInterrupt:
-                    raise
-                except:
-                    if conf.debug_dissector:
+                if pkt is not None:
+                    ts,pkt = pkt
+                    try:
+                        pkt = cls(pkt)
+                    except KeyboardInterrupt:
                         raise
-                    pkt = conf.raw_layer(pkt)
-                pkt.time = ts
+                    except:
+                        if conf.debug_dissector:
+                            raise
+                        pkt = conf.raw_layer(pkt)
+                    pkt.time = ts
                 return pkt
         
             def send(self, x):

scapy/sendrecv.py

@@ -585,7 +585,7 @@ stop_filter: python function applied to each packet to determine
             if s in sel[0]:
                 p = s.recv(MTU)
                 if p is None:
-                    break
+                    continue
                 if lfilter and not lfilter(p):
                     continue
                 if store: