Python中利用原始套接字进行网络编程的示例

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/' target='_blank'>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 sysimport socketfrom 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()