1#!/usr/local/bin/python2.7
2# check wether path mtu to dst is 1300
3
4import os
5from addr import *
6from scapy.all import *
7
8dstaddr=sys.argv[1]
9pid=os.getpid()
10payload="a" * 1452
11a=srp1(Ether(src=SRC_MAC, dst=PF_MAC)/IP(flags="DF", src=SRC_OUT, dst=dstaddr)/
12    ICMP(id=pid)/payload, iface=SRC_IF, timeout=2)
13if a and a.payload.payload.type==3 and a.payload.payload.code==4:
14	mtu=a.payload.payload.unused
15	print "mtu=%d" % (mtu)
16	if mtu == 1300:
17		exit(0)
18	print "MTU!=1300"
19	exit(1)
20print "MTU=UNKNOWN"
21exit(2)
22