import socket

import os
import struct
from ctypes import *



# host to listen on
host = "192.168.16.128"

# IP header
class IP(Structure):
    # map C datataypes to IP header values
    _fields_ = [
        ("ihl",          c_ubyte, 4),
        ("version",      c_ubyte, 4),
        ("tos",          c_ubyte),
        ("len",          c_ushort),
        ("id",           c_ushort),
        ("offset",       c_ushort),
        ("ttl",          c_ubyte),
        ("protocol_num", c_ubyte),
        ("sum",          c_ushort),
        ("src",          c_ulong),
        ("dst",          c_ulong)
    ]

    def __new__(self, socket_buffer=None):
        return self.from_buffer_copy(socket_buffer)

    def __init__(self, socket_buffer=None):

        # map protocol constants to their names
        self.protocol_map = {1:"ICMP", 6:"TCP", 17:"UDP"}

        # human readable IP addresses
        self.src_address = socket.inet_ntoa(struct.pack("<L",self.src))
        self.dst_address = socket.inet_ntoa(struct.pack("<L",self.dst))

        # human readable protocol
        try:
            self.protocol = self.protocol_map[self.protocol_num]
        except:
            self.protocol = str(self.protocol_num)

if os.name == "nt":
    socket_protocol = socket.IPPROTO_IP
else:
    socket_protocol = socket.IPPROTO_ICMP

sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket_protocol)

sniffer.bind((host, 0))
sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)

if os.name == "nt":
    sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)

try:
    while True:

        # read in packet
        raw_buffer = sniffer.recvfrom(6556)[0]

        # create IP header from first 20 bytes of buffer
        ip_header = IP(raw_buffer[0:20])

        # print out protocol that was detected + hosts
        print "Protocol: %s %s -> %s" % (ip_header.protocol, ip_header.src_address, ip_header.dst_address)

# CTRL-C
except:

    # if Windows, turn off promiscuous mode
    if os.name == "nt":
        sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)