I'm writing a script that uses Net:PcapUtils to capture traffic on an ethernet segment. I have the capture working fine, using the Net:PcapUtils::Loop function. Inside that loop, I want the script to stop periodically and listen for a UDP request from a client. The client sends a request like this: 198.59.115.4:34, and the script sends a response like this: 34 198.59.115.4:34, which is a count of how many times it has seen that IP:Port as a destination.

It works, sort of. It counts, it listens, it answers. The problem is this, if it does not receive a request, it seems to wait until it does, not counting in the meantime. I was hoping that an if statement would make it so that if there was no request, it would just continue, but it does not seem to work that way: 

$count ++;
if ($count == 500) {
   $MAXLEN = 1024;
   $PORTNO = 5151;
   $sock = IO:SOCKET::INET->new(LocalPort => $PORTNO, Proto => 'udp')
       or die "socket:  $@";
   if ($sock->recv($request, $MAXLEN))  {
        ...
        close($sock);
        }
        $count = 0;
      }

[download]
So I start up this script and send a request to it from the client. I get a response. If I don't send a request for an hour and then send one, the count is the same. If I just sit there and send mutliple requests, the count goes up.

Any idea how I can get this to work the way I want?

jgentry@swcp.com

In reply to Check for request from UDP client by Anonymous Monk

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