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) 9port=os.getpid() & 0xffff 10 11print "Send SYN packet, receive SYN+ACK." 12syn=TCP(sport=port, dport='chargen', seq=1, flags='S', window=(2**16)-1) 13synack=srp1(e/ip6/syn, iface=LOCAL_IF, timeout=5) 14 15print "Send ack packet, receive chargen data." 16ack=TCP(sport=synack.dport, dport=synack.sport, seq=2, flags='A', 17 ack=synack.seq+1, window=(2**16)-1) 18data=srp1(e/ip6/ack, iface=LOCAL_IF, timeout=5) 19 20print "Fill our receive buffer." 21time.sleep(1) 22 23print "Send ICMP6 packet too big packet with MTU 1300." 24icmp6=ICMPv6PacketTooBig(mtu=1300)/data.payload 25sendp(e/IPv6(src=LOCAL_ADDR6, dst=REMOTE_ADDR6)/icmp6, iface=LOCAL_IF) 26 27print "Path MTU discovery will resend first data with length 1300." 28data=srp1(e/ip6/ack, iface=LOCAL_IF, timeout=5) 29 30print "Cleanup the other's socket with a reset packet." 31rst=TCP(sport=synack.dport, dport=synack.sport, seq=2, flags='AR', 32 ack=synack.seq+1) 33sendp(e/ip6/rst, iface=LOCAL_IF) 34 35len = data.plen + len(IPv6()) 36print "len=%d" % len 37if len != 1300: 38 print "ERROR: TCP data packet len is %d, expected 1300." % len 39 exit(1) 40exit(0) 41