1*647ac401Sbluhm#!/usr/local/bin/python3
23fe81ad4Sbluhm
3*647ac401Sbluhmprint("udp fragments splitted after udp header")
43fe81ad4Sbluhm
53fe81ad4Sbluhm# |----|
63fe81ad4Sbluhm#      |--------|
73fe81ad4Sbluhm
83fe81ad4Sbluhmimport os
93fe81ad4Sbluhmfrom addr import *
103fe81ad4Sbluhmfrom scapy.all import *
113fe81ad4Sbluhm
123fe81ad4Sbluhmpid=os.getpid()
133fe81ad4Sbluhmuport=pid & 0xffff
143fe81ad4Sbluhm# inetd ignores UDP packets from privileged port or nfs
153fe81ad4Sbluhmif uport < 1024 or uport == 2049:
163fe81ad4Sbluhm	uport+=1024
17*647ac401Sbluhmpayload=b"ABCDEFGHIJKLMNOP"
183fe81ad4Sbluhmpacket=IP(src=LOCAL_ADDR, dst=REMOTE_ADDR)/ \
193fe81ad4Sbluhm    UDP(sport=uport, dport=7)/payload
203fe81ad4Sbluhmfrag=[]
213fe81ad4Sbluhmfid=pid & 0xffff
227cd47444Sbluhmfrag.append(IP(src=LOCAL_ADDR, dst=REMOTE_ADDR, proto=17, id=fid,
23*647ac401Sbluhm    flags='MF')/bytes(packet)[20:28])
247cd47444Sbluhmfrag.append(IP(src=LOCAL_ADDR, dst=REMOTE_ADDR, proto=17, id=fid,
25*647ac401Sbluhm    frag=1)/bytes(packet)[28:44])
263fe81ad4Sbluhmeth=[]
273fe81ad4Sbluhmfor f in frag:
283fe81ad4Sbluhm	eth.append(Ether(src=LOCAL_MAC, dst=REMOTE_MAC)/f)
293fe81ad4Sbluhm
303fe81ad4Sbluhmif os.fork() == 0:
313fe81ad4Sbluhm	time.sleep(1)
323fe81ad4Sbluhm	sendp(eth, iface=LOCAL_IF)
333fe81ad4Sbluhm	os._exit(0)
343fe81ad4Sbluhm
353fe81ad4Sbluhmans=sniff(iface=LOCAL_IF, timeout=3, filter=
363fe81ad4Sbluhm    "ip and src "+REMOTE_ADDR+" and dst "+LOCAL_ADDR+" and udp")
373fe81ad4Sbluhmfor a in ans:
383fe81ad4Sbluhm	if a and a.type == ETH_P_IP and \
393fe81ad4Sbluhm	    a.payload.proto == 17 and \
403fe81ad4Sbluhm	    a.payload.frag == 0 and a.payload.flags == 0 and \
413fe81ad4Sbluhm	    a.payload.payload.sport == 7:
423fe81ad4Sbluhm		port=a.payload.payload.dport
43*647ac401Sbluhm		print("port=%d" % (port))
443fe81ad4Sbluhm		if port != uport:
45*647ac401Sbluhm			print("WRONG UDP ECHO REPLY PORT")
463fe81ad4Sbluhm			exit(2)
473fe81ad4Sbluhm		data=a.payload.payload.payload.load
48*647ac401Sbluhm		print("payload=%s" % (data))
493fe81ad4Sbluhm		if data == payload:
503fe81ad4Sbluhm			exit(0)
51*647ac401Sbluhm		print("PAYLOAD!=%s" % (payload))
523fe81ad4Sbluhm		exit(1)
53*647ac401Sbluhmprint("NO UDP ECHO REPLY")
543fe81ad4Sbluhmexit(2)
55