1#!/usr/local/bin/python3
2
3print("ping6 fragment that overlaps the second fragment with its head")
4
5# |----|
6#      |----|
7#      |XXXX-----|
8
9import os
10from addr import *
11from scapy.all import *
12
13pid=os.getpid()
14eid=pid & 0xffff
15payload=b"ABCDEFGHIJKLMNOP"
16packet=IPv6(src=LOCAL_ADDR6, dst=REMOTE_ADDR6)/ \
17    ICMPv6EchoRequest(id=eid, data=payload)
18frag=[]
19fid=pid & 0xffffffff
20frag.append(IPv6ExtHdrFragment(nh=58, id=fid,
21    m=1)/bytes(packet)[40:48])
22frag.append(IPv6ExtHdrFragment(nh=58, id=fid,
23    offset=1, m=1)/bytes(packet)[48:56])
24frag.append(IPv6ExtHdrFragment(nh=58, id=fid,
25    offset=1)/bytes(packet)[48:64])
26eth=[]
27for f in frag:
28	pkt=IPv6(src=LOCAL_ADDR6, dst=REMOTE_ADDR6)/f
29	eth.append(Ether(src=LOCAL_MAC, dst=REMOTE_MAC)/pkt)
30
31if os.fork() == 0:
32	time.sleep(1)
33	sendp(eth, iface=LOCAL_IF)
34	os._exit(0)
35
36ans=sniff(iface=LOCAL_IF, timeout=3, filter=
37    "ip6 and src "+REMOTE_ADDR6+" and dst "+LOCAL_ADDR6+" and icmp6")
38for a in ans:
39	if a and a.type == ETH_P_IPV6 and \
40	    ipv6nh[a.payload.nh] == 'ICMPv6' and \
41	    icmp6types[a.payload.payload.type] == 'Echo Reply':
42		id=a.payload.payload.id
43		print("id=%#x" % (id))
44		if id != eid:
45			print("WRONG ECHO REPLY ID")
46			exit(2)
47		data=a.payload.payload.data
48		print("payload=%s" % (data))
49		if data == payload:
50			print("ECHO REPLY")
51			exit(1)
52		print("PAYLOAD!=%s" % (payload))
53		exit(2)
54print("no echo reply")
55exit(0)
56