1#!/usr/local/bin/python3 2 3print("udp fragments with splitted payload") 4 5# |--------| 6# |----| 7 8import os 9from addr import * 10from scapy.all import * 11 12pid=os.getpid() 13uport=pid & 0xffff 14# inetd ignores UDP packets from privileged port or nfs 15if uport < 1024 or uport == 2049: 16 uport+=1024 17payload=b"ABCDEFGHIJKLMNOP" 18packet=IPv6(src=LOCAL_ADDR6, dst=REMOTE_ADDR6)/ \ 19 UDP(sport=uport, dport=7)/payload 20frag=[] 21fid=pid & 0xffffffff 22frag.append(IPv6ExtHdrFragment(nh=17, id=fid, m=1)/bytes(packet)[40:56]) 23frag.append(IPv6ExtHdrFragment(nh=17, id=fid, offset=2)/bytes(packet)[56:64]) 24eth=[] 25for f in frag: 26 pkt=IPv6(src=LOCAL_ADDR6, dst=REMOTE_ADDR6)/f 27 eth.append(Ether(src=LOCAL_MAC, dst=REMOTE_MAC)/pkt) 28 29if os.fork() == 0: 30 time.sleep(1) 31 sendp(eth, iface=LOCAL_IF) 32 os._exit(0) 33 34ans=sniff(iface=LOCAL_IF, timeout=3, filter= 35 "ip6 and src "+REMOTE_ADDR6+" and dst "+LOCAL_ADDR6+" and udp") 36for a in ans: 37 if a and a.type == ETH_P_IPV6 and \ 38 ipv6nh[a.payload.nh] == 'UDP' and \ 39 a.payload.payload.sport == 7: 40 port=a.payload.payload.dport 41 print("port=%d" % (port)) 42 if port != uport: 43 print("WRONG UDP ECHO REPLY PORT") 44 exit(2) 45 data=a.payload.payload.load 46 print("payload=%s" % (data)) 47 if data == payload: 48 exit(0) 49 print("PAYLOAD!=%s" % (payload)) 50 exit(1) 51print("NO UDP ECHO REPLY") 52exit(2) 53