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()
