Python原始套接字编程

在实验中需要自己构造单独的HTTP数据报文，而使用SOCK_STREAM进行发送数据包，需要进行完整的TCP交互。

因此想使用原始套接字进行编程，直接构造数据包，并在IP层进行发送，即采用SOCK_RAW进行数据发送。

使用SOCK_RAW的优势是，可以对数据包进行完整的修改，可以处理IP层上的所有数据包，对各字段进行修改，而不受UDP和TCP的限制。

下面开始构造HTTP数据包，

IP层和TCP层使用python的Impacket库，http内容自行填写。

#!/usr/bin/env python

#-------------------------------------------------------------------------------
# Name:     raw_http.py
# Purpose:       construct a raw http get packet
#
# Author:	 Yangjun
#
# Created:       08/02/2014
# Copyright:   (c) Yangjun 2014
# Licence:       <your licence>
#-------------------------------------------------------------------------------

import sys
import socket
from impacket import ImpactDecoder, ImpactPacket

def main():

	if len(sys.argv) < 3:
		print "Use: %s <src ip> <dst ip>" % sys.argv[0]
		print "Use: %s <src ip> <dst ip> <cnt>" % sys.argv[0]
		sys.exit(1)
	elif len(sys.argv) == 3:
		src = sys.argv[1]
		dst = sys.argv[2]
		cnt = 1
	elif len(sys.argv) ==4:
		src = sys.argv[1]
		dst = sys.argv[2]
		cnt = sys.argv[3]
	else:
		print "Input error!"
		sys.exit(1)
#print src, dst
	ip = ImpactPacket.IP()
	ip.set_ip_src(src)
	ip.set_ip_dst(dst)

	# Create a new ICMP packet of type ECHO.
	icmp = ImpactPacket.ICMP()
	tcp = ImpactPacket.TCP()
	tcp.set_th_sport(55968)
	tcp.set_th_dport(80)
	tcp.set_th_seq(1)
	tcp.set_th_ack(1)
	tcp.set_th_flags(0x18)
	tcp.set_th_win(64)

	tcp.contains( ImpactPacket.Data("GET /att/DIYLife/41264/528 HTTP/1.1\r\nHost: 192.168.111.1\r\nAccept-Encoding: identity\r\n\r\n"))

	ip.contains(tcp)

	# Open a raw socket. Special permissions are usually required.
	s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_TCP)
	s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
	seq_id = 0
	while cnt >= 1:
		# Calculate its checksum.
		seq_id = seq_id + 1
		tcp.set_th_seq(seq_id)
		tcp.calculate_checksum()

		# Send it to the target host.
		s.sendto(ip.get_packet(), (dst,80))
		cnt= cnt -1

if __name__ == '__main__':
	main()

运行后抓包如下：