hello every one.....
i made this packet sniffer while experimneting with Net::Pcap module...... and it kinda...... works (wow 8-o)
so here it goes
use Net::Pcap;
use strict; #i am very careless
#look up a device to be used (the active NIC)
my $err="blah";
my $dev=Net::Pcap::lookup_dev(\$err) or die "error:\t$err\n";
#open the device in live mode to sniff out packets
my ($promisc,$snaplen,$to_ms);
$promisc=1; #watchout for any damn packet
$snaplen=150; #atleast 80 chars
$to_ms=100; #wait for 1 sec
$pcap=Net::Pcap::open_live($dev,$snaplen,$promisc,$to_ms);
#loop infinitely until an error occurs
#and call the packet processing subroutine
Net::Pcap::loop($pcap,-1,\&pack_pro,0);
sub pack_pro{
#this is the actual packet processor
my($user_data,$header,$packet)=@_;
# extract the source IP addr into dotted quad form
my($source) = sprintf("%d.%d.%d.%d",
ord( substr($packet, $src_ip, 1) ),
ord( substr($packet, $src_ip+1, 1) ),
ord( substr($packet, $src_ip+2, 1) ),
ord( substr($packet, $src_ip+3, 1) ));
# extract the destination IP addr into dotted quad form
my($destination) = sprintf("%d.%d.%d.%d",
ord( substr($packet, $dst_ip, 1) ),
ord( substr($packet, $dst_ip+1, 1) ),
ord( substr($packet, $dst_ip+2, 1) ),
ord( substr($packet, $dst_ip+3, 1) ));
#the above part is directly taken from "hacking linux exposed" (sorry
+but couldn't figure out this part)
my $data=substr($packet,$domain_start);
#change domain component seperator back into dots
$data=~s/[^-A-Za-z0-9]/./g;
#print the packet
print "$source->$destination\n$data\n";
}#sub routine ends
i thought of coding it in C but steadily perl is taking over as the more preferred language......
please do give the feedback......
i need it.....
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