I would like to send fragmented packets size of 8 bytes and a random starting offset. Also want to leave out the last fragmented packet.
So far I got everything except the fragment of
from scapy.all import *
from random import randint
dip="MY.IP.ADD.RESS"
payload="A"*250+"B"*500
packet=IP(dst=dip,id=12345,off=123)/UDP(sport=1500,dport=1501)/payload
frags=fragment(packet,fragsize=8)
print(packet.show())
for f in frags:
send(f)
What does the above code do? It sends IP Fragment Packets size of 8 byte to a destination IP address.
I would like to send IP Fragment Packets with a random Frag Offset.
I can't find anything about fragment() and the only field, I was able to edit was in IP packet instead of each fragmented IP packet.
Does someone have an idea to accomplish this?
Infos: Python2.7, latest version of scapy (pip)
If you want to generate "broken" fragment offset fields, you have to do that yourself. The scapy fragment() function is simple enough:
def fragment(pkt, fragsize=1480):
"""Fragment a big IP datagram"""
fragsize = (fragsize + 7) // 8 * 8
lst = []
for p in pkt:
s = raw(p[IP].payload)
nb = (len(s) + fragsize - 1) // fragsize
for i in range(nb):
q = p.copy()
del(q[IP].payload)
del(q[IP].chksum)
del(q[IP].len)
if i != nb - 1:
q[IP].flags |= 1
q[IP].frag += i * fragsize // 8 # <---- CHANGE THIS
r = conf.raw_layer(load=s[i * fragsize:(i + 1) * fragsize])
r.overload_fields = p[IP].payload.overload_fields.copy()
q.add_payload(r)
lst.append(q)
return lst
If you change the marked code line above, you can set the fragment offset to whatever you want.