fix Mac OS X pcap problem, I hope

CHANGELOG

@@ -1,4 +1,8 @@
 # Nmap Changelog ($Id$); -*-text-*-
+o Fixed (I hope) a bug related to Pcap capture on Mac OS X.  Thanks to
+  Christophe Thil for reporting the problem and to Kurt Grutzmacher
+  and Diman Todorov for helping to track it down.
+
 o Upgraded the included LibPCRE from version 6.4 to 6.7.  Thanks to
   Jochen Voß (voss(a)seehuhn.de) for the suggestion (he found some bugs
   in 6.4)

osscan2.cc

@@ -3256,7 +3256,7 @@ static void begin_sniffer(HostOsScan *HOS, vector<Target *> &Targets) {
   }
   filterlen = 0;
 
-  HOS->pd = my_pcap_open_live(Targets[0]->deviceName(), 8192,  (o.spoofsource)? 1 : 0, 2);
+  HOS->pd = my_pcap_open_live(Targets[0]->deviceName(), 8192,  (o.spoofsource)? 1 : 0, pcap_selectable_fd_valid()? 200 : 2);
 
   if (doIndividual)
     len = snprintf(pcap_filter, sizeof(pcap_filter), "dst host %s and (icmp or (tcp and (%s", 

scan_engine.cc

@@ -3209,7 +3209,7 @@ static void begin_sniffer(UltraScanInfo *USI, vector<Target *> &Targets) {
   }
   filterlen = 0;
 
-  USI->pd = my_pcap_open_live(Targets[0]->deviceName(), 100,  (o.spoofsource)? 1 : 0, 2);
+  USI->pd = my_pcap_open_live(Targets[0]->deviceName(), 100,  (o.spoofsource)? 1 : 0, pcap_selectable_fd_valid()? 200 : 2);
 
   if (USI->tcp_scan || USI->udp_scan) {
     if (doIndividual)

targets.cc

@@ -1579,7 +1579,7 @@ static void massping(Target *hostbatch[], int num_hosts,
        16 bytes of the TCP header
        ---
        = 104 byte snaplen */
-    pd = my_pcap_open_live(hostbatch[0]->deviceName(), 104, o.spoofsource, 20);
+    pd = my_pcap_open_live(hostbatch[0]->deviceName(), 104, o.spoofsource, pcap_selectable_fd_valid()? 200 : 15);
 
     snprintf(filter, sizeof(filter), "(icmp and dst host %s) or ((tcp or udp) and dst host %s and ( dst port %d or dst port %d or dst port %d or dst port %d or dst port %d))", 
 	     inet_ntoa(hostbatch[0]->v4source()),

tcpip.cc

@@ -1844,12 +1844,9 @@ if (!pd) fatal("NULL packet device passed to readip_pcap");
    gettimeofday(&tv_start, NULL);
  }
 
-// Add other systems here if they don't support select()able pcap descriptors
-#ifdef WIN32
  pcap_descriptor = -1;
-#else
+ if (pcap_selectable_fd_valid())  
    pcap_descriptor = pcap_get_selectable_fd(pd);
-#endif
 
  do {
 #ifdef WIN32
@@ -1951,6 +1948,16 @@ if (timedout) {
  return alignedbuf;
 }
 
+// Returns whether the system supports pcap_get_selectable_fd() properly
+bool pcap_selectable_fd_valid() {
+#if defined(WIN32) || defined(MACOSX)
+  return false;
+#endif
+  return true;
+}
+
+
+ 
 // Returns whether the packet receive time value obtained from libpcap
 // (and thus by readip_pcap()) should be considered valid.  When
 // invalid (Windows and Amiga), readip_pcap returns the time you called it.
@@ -2069,12 +2076,9 @@ int read_arp_reply_pcap(pcap_t *pd, u8 *sendermac, struct in_addr *senderIP,
     }
 #endif
 
-// Add other systems here if they don't support select()able pcap descriptors
-#ifdef WIN32
    pcap_descriptor = -1;
-#else
+   if (pcap_selectable_fd_valid())  
      pcap_descriptor = pcap_get_selectable_fd(pd);
-#endif
     
    p = NULL;
    if (pcap_descriptor != -1) {

tcpip.h

@@ -617,6 +617,11 @@ int send_udp_raw_decoys( int sd, struct eth_nfo *eth,
    So a valid pcap_t will always be returned. */
 pcap_t *my_pcap_open_live(const char *device, int snaplen, int promisc, 
 			  int to_ms);
+
+// Returns whether the system supports pcap_get_selectable_fd() properly
+bool pcap_selectable_fd_valid();
+
+
 // Returns whether the packet receive time value obtaned from libpcap
 // (and thus by readip_pcap()) should be considered valid.  When
 // invalid (Windows and Amiga), readip_pcap returns the time you called it.