python构造IP报文
import socket import sys import time import struct HOST, PORT = "10.60.66.66", 10086 def make_forward_iphdr(source_ip = '1.0.0.1', dest_ip = '2.0.0.2', proto = socket.IPPROTO_UDP) : # ip header fields ip_ihl = 5 ip_ver = 4 ip_tos = 0 ip_tot_len = 0 # kernel will fill the correct total length ip_id = 54321 #Id of this packet ip_frag_off = 0 ip_ttl = 255 ip_proto = proto ip_check = 0 # kernel will fill the correct checksum ip_saddr = socket.inet_aton ( source_ip ) #Spoof the source ip address if you want to ip_daddr = socket.inet_aton ( dest_ip ) ip_ihl_ver = (ip_ver << 4) + ip_ihl # the ! in the pack format string means network order ip_header = struct.pack('!BBHHHBBH4s4s', ip_ihl_ver, ip_tos, ip_tot_len, ip_id, ip_frag_off, ip_ttl, ip_proto, ip_check, ip_saddr, ip_daddr) return ip_header def make_forward_udphdr(src_port = 1024, dst_port = 10086) : udp_header = struct.pack('!HHHH', src_port, dst_port, 0, 0) return udp_header # checksum functions needed for calculation checksum def checksum(msg): s = 0 # loop taking 2 characters at a time for i in range(0, len(msg), 2): w = ord(msg[i]) + (ord(msg[i+1]) << 8 ) s = s + w s = (s>>16) + (s & 0xffff); s = s + (s >> 16); #complement and mask to 4 byte short s = ~s & 0xffff return s def make_tcp_data(ip_header, src_port = 1024, dst_port = 10086, source_ip='1.0.0.1', dest_ip='2.0.0.2', user_data = 'test') : tcp_source = src_port # source port tcp_dest = dst_port # destination port tcp_seq = 454 tcp_ack_seq = 0 tcp_doff = 5 #4 bit field, size of tcp header, 5 * 4 = 20 bytes #tcp flags tcp_fin = 0 tcp_syn = 1 tcp_rst = 0 tcp_psh = 0 tcp_ack = 0 tcp_urg = 0 tcp_window = socket.htons (5840) # maximum allowed window size tcp_check = 0 tcp_urg_ptr = 0 tcp_offset_res = (tcp_doff << 4) + 0 tcp_flags = tcp_fin + (tcp_syn << 1) + (tcp_rst << 2) + (tcp_psh <<3) + (tcp_ack << 4) + (tcp_urg << 5) # the ! in the pack format string means network order tcp_header = struct.pack('!HHLLBBHHH' , tcp_source, tcp_dest, tcp_seq, tcp_ack_seq, tcp_offset_res, tcp_flags, tcp_window, tcp_check, tcp_urg_ptr) source_address = socket.inet_aton(source_ip) dest_address = socket.inet_aton(dest_ip) placeholder = 0 protocol = socket.IPPROTO_TCP tcp_length = len(tcp_header) + len(user_data) psh = struct.pack('!4s4sBBH' , source_address , dest_address , placeholder , protocol , tcp_length); psh = psh + tcp_header + user_data; tcp_check = checksum(psh) #print tcp_checksum # make the tcp header again and fill the correct checksum - remember checksum is NOT in network byte order tcp_header = struct.pack('!HHLLBBH' , tcp_source, tcp_dest, tcp_seq, tcp_ack_seq, tcp_offset_res, tcp_flags, tcp_window) + struct.pack('H' , tcp_check) + struct.pack('!H' ,tcp_urg_ptr) # final full packet - syn packets dont have any data packet = ip_header + tcp_header + user_data return packet
