Your example on my system also produced similar results. But, using "alarm" function in my packet count program as shown below, had similar random results. 

#!/usr/bin/perl -w

use strict;
use English;
use Net::Pcap;
use Time::HiRes qw (alarm time );

my($dev, $pcap_t, $err);

$dev = Net::Pcap::lookupdev(\$err);
$pcap_t = Net::Pcap::open_live($dev, 1500, 1, 0, \$err);

my $count = 0;
sub process_pkt {
    my ( $user_data, $hdr, $pkt ) = @_;
    $count++;
    $SIG{ALRM} = sub { printf ("%16.5f %d\n", time, $count); $count = 
+0 };
#    setitimer(ITIMER_REAL, 0.5, 0.5);
    alarm(0.5);
}

Net::Pcap::loop( $pcap_t, 0, \&process_pkt, "argument");
Net::Pcap::close($pcap_t);

[download]


1069653942.70856 6
1069653948.50819 69
1069653949.46479 2
1069653952.55703 4
1069654021.47634 6
1069654026.47576 4
1069654147.79127 2
1069654173.53735 6
1069654174.43908 2

probably, both packet capturing and alarming are too much for perl, to do it precisely the way we want.

Can you please elaborate on "printing packets/second". Net::Pcap doesn't seem to have any function that would capture packets in regular intervals of time. Any help about how I can get "no of packets/second" will be very helpful.

Thanks,
prakash.

In reply to Re: Re: IP Packet count at regular intervals of time by prakashrj
in thread IP Packet count at regular intervals of time by prakashrj

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