1#!/usr/local/bin/python3
2# old fragment completely overlaps new one
3
4#      |------------|
5#          |XXXX|
6# |----|
7
8# RFC 5722 drop overlapping fragments
9
10import os
11import threading
12from addr import *
13from scapy.all import *
14
15class Sniff1(threading.Thread):
16	filter = None
17	captured = None
18	packet = None
19	def run(self):
20		self.captured = sniff(iface=SRC_IF, filter=self.filter,
21		    count=1, timeout=3)
22		if self.captured:
23			self.packet = self.captured[0]
24
25dstaddr=sys.argv[1]
26pid=os.getpid()
27eid=pid & 0xffff
28payload=b"ABCDEFGHIJKLOMNOQRSTUVWX"
29dummy=b"01234567"
30packet=IPv6(src=SRC_OUT6, dst=dstaddr)/ICMPv6EchoRequest(id=eid, data=payload)
31fid=pid & 0xffffffff
32frag0=IPv6ExtHdrFragment(nh=58, id=fid, offset=0, m=1)/bytes(packet)[40:48]
33frag1=IPv6ExtHdrFragment(nh=58, id=fid, offset=2, m=1)/dummy
34frag2=IPv6ExtHdrFragment(nh=58, id=fid, offset=1)/bytes(packet)[48:72]
35pkt0=IPv6(src=SRC_OUT6, dst=dstaddr)/frag0
36pkt1=IPv6(src=SRC_OUT6, dst=dstaddr)/frag1
37pkt2=IPv6(src=SRC_OUT6, dst=dstaddr)/frag2
38eth=[]
39eth.append(Ether(src=SRC_MAC, dst=PF_MAC)/pkt2)
40eth.append(Ether(src=SRC_MAC, dst=PF_MAC)/pkt1)
41eth.append(Ether(src=SRC_MAC, dst=PF_MAC)/pkt0)
42
43sniffer = Sniff1();
44sniffer.filter = "ip6 and src %s and dst %s and icmp6" % (dstaddr, SRC_OUT6)
45sniffer.start()
46time.sleep(1)
47sendp(eth, iface=SRC_IF)
48sniffer.join(timeout=5)
49a = sniffer.packet
50
51if a is None:
52	print("no reply")
53	exit(0)
54if a and a.type == ETH_P_IPV6 and \
55    ipv6nh[a.payload.nh] == 'ICMPv6' and \
56    icmp6types[a.payload.payload.type] == 'Echo Reply':
57	id=a.payload.payload.id
58	print("id=%#x" % (id))
59	if id != eid:
60		print("WRONG ECHO REPLY ID")
61		exit(2)
62	data=a.payload.payload.data
63	print("payload=%s" % (data))
64	if data == payload:
65		print("ECHO REPLY")
66		exit(1)
67	print("PAYLOAD!=%s" % (payload))
68	exit(2)
69print("NO ECHO REPLY")
70exit(2)
71