--- /dev/null
+#!/usr/bin/perl
+
+# Module: VNET+
+# Description:
+# Generate a ton of connections and check if we can see syn/ack packets via tcpdump.
+# Author: sapanb@cs.princeton.edu
+
+use strict;
+use IO::Socket;
+use threads;
+use threads::shared;
+
+my $guineapig='www.cs.princeton.edu';
+my $targetfile='/~sapanb/small';
+my $magic='3j4kl;1234kj341234jl1k234ljk123h4';
+my $numiter=1000;
+my $numsynacks:shared=0;
+my $numthreads=4;
+my $numpackets=$numthreads*$numiter;
+
+sub fetch {
+ my $sock = new IO::Socket::INET (
+ PeerAddr => $guineapig,
+ PeerPort => 80,
+ Proto => 'tcp'
+ );
+ return 0 unless $sock;
+ print $sock "GET $targetfile HTTP/1.0\r\n";
+ print $sock "Host: www.cs.princeton.edu\r\n";
+ print $sock "\r\n";
+
+ my $success=0;
+ while (<$sock>) {
+ if (/$magic/g) {
+ $success=1;
+ last;
+ }
+ }
+ close ($sock);
+ if ($success==1) {
+ $numsynacks=$numsynacks+1;
+ }
+ return $success;
+}
+
+sub mfetch {
+ foreach (1..$numiter) {
+ fetch;
+ }
+}
+
+sub launch {
+ my @tarray;
+ foreach (1..$numthreads) {
+ my $thr = threads->create(\&mfetch);
+ push @tarray,$thr;
+ }
+
+ for (@tarray) {
+ $_->join;
+ }
+}
+
+sub open_tcpdump {
+ my $filter="'tcp[tcpflags]&tcp-syn !=0 and tcp[tcpflags]&tcp-ack !=0 and src $guineapig'";
+ my $cmdline="/usr/sbin/tcpdump -c $numpackets $filter";
+ my $p;
+
+ system($cmdline);
+}
+
+sub alhandler {
+ print "[FAILED] tcpdump apparently did not intercept all SYN/ACK packets\n";
+ exit(-1);
+}
+
+print "Starting tcpdump...\n";
+my $tcpdthr=threads->create(\&open_tcpdump);
+sleep 10;
+print "Generating connections...\n";
+launch;
+$SIG{ALRM}=\&alhandler;
+alarm(60);
+$tcpdthr->join;
+$numsynacks++;
+print "[SUCCESS] Test completed OK. $numsynacks SYN/ACK packets intercepted.\n";