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#!/usr/local/bin/python2.7
import os
import string
import random
from addr import *
from scapy.all import *
e=Ether(src=LOCAL_MAC, dst=REMOTE_MAC)
ip6=IPv6(src=FAKE_NET_ADDR6, dst=REMOTE_ADDR6)
port=os.getpid() & 0xffff
# inetd ignores packets from privileged port or nfs
if port < 1024 or port == 2049:
port+=1024
print "Send UDP packet with 1200 octets payload, receive echo."
data=''.join(random.choice(string.ascii_uppercase + string.ascii_lowercase +
string.digits) for _ in range(1200))
udp=UDP(sport=port, dport='echo')/data
echo=srp1(e/ip6/udp, iface=LOCAL_IF, timeout=5)
if echo is None:
print "ERROR: no UDP answer from echo server received"
exit(1)
print "Send ICMP6 packet too big packet with MTU 1272."
icmp6=ICMPv6PacketTooBig(mtu=1272)/echo.payload
sendp(e/IPv6(src=LOCAL_ADDR6, dst=REMOTE_ADDR6)/icmp6, iface=LOCAL_IF)
print "Clear route cache at echo socket by sending from different address."
sendp(e/IPv6(src=LOCAL_ADDR6, dst=REMOTE_ADDR6)/udp, iface=LOCAL_IF)
print "Path MTU discovery will send UDP atomic fragment with length 1256."
# srp1 cannot be used, fragment answer will not match on outgoing udp packet
if os.fork() == 0:
time.sleep(1)
sendp(e/ip6/udp, iface=LOCAL_IF)
os._exit(0)
ans=sniff(iface=LOCAL_IF, timeout=3, filter=
"ip6 and src "+ip6.dst+" and dst "+ip6.src+" and proto ipv6-frag")
for a in ans:
fh=a.payload.payload
if fh.offset != 0 or fh.nh != (ip6/udp).nh:
continue
uh=fh.payload
if uh.sport != udp.dport or uh.dport != udp.sport:
continue
frag=a
break
else:
print "ERROR: no matching IPv6 fragment UDP answer found"
exit(1)
if frag.offset != 0:
print "ERROR: TCP fragment is not atomic, offset is %d." % frag.offset
exit(1)
if frag.m != 0:
print "ERROR: TCP fragment is not atomic, more fragment bit is set."
exit(1)
print "UDP echo has IPv6 and UDP header, so expected payload len is 1248"
elen = echo.plen + len(IPv6())
print "elen=%d" % elen
if elen != 1248:
print "ERROR: UDP echo payload len is %d, expected 1248." % elen
exit(1)
print "Atomic fragment contains 8 octet header, so expected len is 1256"
flen = frag.plen + len(IPv6())
print "flen=%d" % flen
if flen != 1256:
print "ERROR: UDP atomic fragment len is %d, expected 1256." % flen
exit(1)
exit(0)
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