Eddie traceroute localhost fix

CHANGELOG

@@ -8,6 +8,10 @@ o Fixed a bug which prevented the NSE scripts directory from appearing
 o Fixed a bug in Traceroute's output.  It occured when a traced host could
   be fully consolidated, but only the first hop number was outputted. [Kris]
 
+o Fixed a Traceroute bug relating to scanning through the localhost
+  interface on Windows (which previously caused a crash).  Thanks to
+  Alan Jones for the report and Eddie Bell for the fix.
+
 o Updated IANA assignment IP list for random IP (-iR) generation. [Kris]
 
 4.21ALPHA4

traceroute.cc

@@ -198,8 +198,12 @@ Traceroute::Traceroute (const char *device_name, devtype type) {
     fd = -1;
     ethsd = NULL;
     hops = NULL;
+    pd = NULL;
     total_size = 0;
 
+    if(type == devt_loopback) 
+        return;
+
     /* open various socks to send and read from on windows and 
      * unix */
     if ((o.sendpref & PACKET_SEND_ETH) && type == devt_ethernet) {
@@ -305,8 +309,10 @@ Traceroute::~Traceroute () {
         delete (it->second);
     if (ethsd)
         ethsd = NULL;
-    close (fd);
-    pcap_close (pd);
+    if (fd != -1)
+        close (fd);
+    if(pd)
+        pcap_close (pd);
 }
 
 /* get an open or closed port from the portlist. Traceroute requires a positive response,