sniff_network_beta.py

#!/usr/bin/python
 
import socket, sys
import zlib
from struct import *
 
#Convert a string of 6 characters of ethernet address into a dash separated hex string
def eth_addr (a) :
  b = "%.2x:%.2x:%.2x:%.2x:%.2x:%.2x" % (ord(a[0]) , ord(a[1]) , ord(a[2]), ord(a[3]), ord(a[4]) , ord(a[5]))
  return b
 
#create a AF_PACKET type raw socket (thats basically packet level)
#define ETH_P_ALL    0x0003          /* Every packet (be careful!!!) */
try:
    s = socket.socket( socket.AF_PACKET , socket.SOCK_RAW , socket.ntohs(0x0003))
except socket.error , msg:
    print 'Socket could not be created. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
    sys.exit()
 
# receive a packet
while True:
    packet = s.recvfrom(65565)
     
    #packet string from tuple
    packet = packet[0]
     
    #parse ethernet header
    eth_length = 14
     
    eth_header = packet[:eth_length]
    eth = unpack('!6s6sH' , eth_header)
    eth_protocol = socket.ntohs(eth[2])
    #print 'Destination MAC : ' + eth_addr(packet[0:6]) + ' Source MAC : ' + \
    # eth_addr(packet[6:12]) + ' Protocol : ' + str(eth_protocol)
 
    #Parse IP packets, IP Protocol number = 8
    if eth_protocol == 8 :
        #Parse IP header
        #take first 20 characters for the ip header
        ip_header = packet[eth_length:20+eth_length]
         
        #now unpack them :)
        iph = unpack('!BBHHHBBH4s4s' , ip_header)
 
        version_ihl = iph[0]
        version = version_ihl >> 4
        ihl = version_ihl & 0xF
 
        iph_length = ihl * 4
 
        ttl = iph[5]
        protocol = iph[6]
        s_addr = socket.inet_ntoa(iph[8]);
        d_addr = socket.inet_ntoa(iph[9]);
 
        #print 'Version : ' + str(version) + ' IP Header Length : ' + str(ihl) + ' TTL : ' + str(ttl) + \
        # ' Protocol : ' + str(protocol) + ' Source Address : ' + str(s_addr) + ' Destination Address : ' +\
        # str(d_addr)
 
        #TCP protocol
        if protocol == 6 :
            t = iph_length + eth_length
            tcp_header = packet[t:t+20]
 
            #now unpack them :)
            tcph = unpack('!HHLLBBHHH' , tcp_header)
             
            source_port = tcph[0]
            dest_port = tcph[1]
            sequence = tcph[2]
            acknowledgement = tcph[3]
            doff_reserved = tcph[4]
            tcph_length = doff_reserved >> 4

            #print 'NETWORK LAYER::::: Source Address : ' + str(s_addr) + ' Destination Address : ' + str(d_addr);
             
            #print 'TRANSPORT LAYER::: Source Port : ' + str(source_port) + \
            #    ' Dest Port : ' + str(dest_port) + ' Sequence Number : ' + str(sequence) + ' Acknowledgement : ' + \
            #     str(acknowledgement) + ' TCP header length : ' + str(tcph_length);
             
            h_size = eth_length + iph_length + tcph_length * 4
            data_size = len(packet) - h_size
             
            #get data from the packet
            data = packet[h_size:]
           
            if data[:3]=='GET':
		host = 'unknown';
		lines = data.split('\r\n');
		for line in lines[1:]:
			try:
				key = line.split(':')[0];
				value = line.split(':')[1];
				if key == 'Host':
					host = value;
			except:
				break;
                print str(s_addr)+' is requesting from'+host+" ("+str(d_addr)+")";