tcp_connect6.py revision 1.6 
1#!/usr/local/bin/python2.7
2
3import os
4from addr import *
5from scapy.all import *
6
7e=Ether(src=LOCAL_MAC, dst=REMOTE_MAC)
8ip6=IPv6(src=FAKE_NET_ADDR6, dst=REMOTE_ADDR6)
9tport=os.getpid() & 0xffff
10
11print "Send SYN packet, receive SYN+ACK."
12syn=TCP(sport=tport, dport='chargen', seq=1, flags='S', window=(2**16)-1)
13synack=srp1(e/ip6/syn, iface=LOCAL_IF, timeout=5)
14
15if synack is None:
16	print "ERROR: no SYN+ACK from chargen server received"
17	exit(1)
18
19print "Send ACK packet, receive chargen data."
20ack=TCP(sport=synack.dport, dport=synack.sport, seq=2, flags='A',
21    ack=synack.seq+1, window=(2**16)-1)
22data=srp1(e/ip6/ack, iface=LOCAL_IF, timeout=5)
23
24if data is None:
25	print "ERROR: no data from chargen server received"
26	exit(1)
27
28print "Fill our receive buffer."
29time.sleep(1)
30
31print "Send ICMP6 packet too big packet with MTU 1300."
32icmp6=ICMPv6PacketTooBig(mtu=1300)/data.payload
33# srp1 cannot be used, TCP data will not match outgoing ICMP6 packet
34if os.fork() == 0:
35	time.sleep(1)
36	sendp(e/IPv6(src=LOCAL_ADDR6, dst=REMOTE_ADDR6)/icmp6, iface=LOCAL_IF)
37	os._exit(0)
38
39print "Path MTU discovery will resend first data with length 1300."
40ans=sniff(iface=LOCAL_IF, timeout=3, count=1, filter=
41    "ip6 and src %s and tcp port %u and dst %s and tcp port %u" %
42    (ip6.dst, syn.dport, ip6.src, syn.sport))
43
44if len(ans) == 0:
45	print "ERROR: no data retransmit from chargen server received"
46	exit(1)
47data=ans[0]
48
49print "Cleanup the other's socket with a reset packet."
50rst=TCP(sport=synack.dport, dport=synack.sport, seq=2, flags='AR',
51    ack=synack.seq+1)
52sendp(e/ip6/rst, iface=LOCAL_IF)
53
54len = data.plen + len(IPv6())
55print "len=%d" % len
56if len != 1300:
57	print "ERROR: TCP data packet len is %d, expected 1300." % len
58	exit(1)
59
60exit(0)
61