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#!/usr/local/bin/python2.7
# new fragment completely overlaps old one
# |----|
# |XXXX|
# |------------|
# If an existing fragment is completely overlapped by the current
# one, drop the older fragment.
# TAILQ_REMOVE(&frag->fr_queue, after, fr_next);
# Smaller older fragments might not have been nearer, and might be
# trying to overwrite a very small part of the full packet.
import os
from addr import *
from scapy.all import *
dstaddr=sys.argv[1]
pid=os.getpid()
payload="ABCDEFGHIJKLOMNOQRSTUVWX"
dummy="01234567"
packet=IP(src=SRC_OUT, dst=dstaddr)/ICMP(id=pid)/payload
frag0=str(packet)[20:28]
frag1=dummy
frag2=str(packet)[28:52]
pkt0=IP(src=SRC_OUT, dst=dstaddr, proto=1, id=pid, frag=0, flags='MF')/frag0
pkt1=IP(src=SRC_OUT, dst=dstaddr, proto=1, id=pid, frag=2, flags='MF')/frag1
pkt2=IP(src=SRC_OUT, dst=dstaddr, proto=1, id=pid, frag=1)/frag2
eth=[]
eth.append(Ether(src=SRC_MAC, dst=PF_MAC)/pkt0)
eth.append(Ether(src=SRC_MAC, dst=PF_MAC)/pkt1)
eth.append(Ether(src=SRC_MAC, dst=PF_MAC)/pkt2)
if os.fork() == 0:
time.sleep(1)
sendp(eth, iface=SRC_IF)
os._exit(0)
ans=sniff(iface=SRC_IF, timeout=3, filter=
"ip and src "+dstaddr+" and dst "+SRC_OUT+" and icmp")
a=ans[0]
if a and a.type == scapy.layers.dot11.ETHER_TYPES.IPv4 and \
a.payload.proto == 1 and \
a.payload.frag == 0 and a.payload.flags == 0 and \
icmptypes[a.payload.payload.type] == 'echo-reply':
id=a.payload.payload.id
print "id=%#x" % (id)
if id != pid:
print "WRONG ECHO REPLY ID"
exit(2)
load=a.payload.payload.payload.load
print "payload=%s" % (load)
if load == payload:
exit(0)
print "PAYLOAD!=%s" % (payload)
exit(1)
print "NO ECHO REPLY"
exit(2)
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