use Net::Pcap;

my $device = ...
my $snaplen = ...
my $timeout = ... * 1000 # in milliseconds * 1000 = seconds
my $err;

my $pcaprecv = Net::Pcap::pcap_open_live($device, $snaplen, 1, $timeout, \$err);

my $recv_r;
my %header;
my $starttime = time;
while (1) {
    my $ret = Net::Pcap::pcap_next_ex($pcaprecv, \%header, \$recv_r);
    if ($ret == 1) {
        # Found packet - do stuff
    } elsif ($ret == 0) {
        print "[Receive Timeout] ";
        last
    } else {
        print "[Receive Error] ";
        last
    }
    if ((time - $starttime) >= $timeout) {
        print "[Receive Timeout] ";
        last
    }
}