CODEWITHSUNDEEP
pythonscapy
Kamook
Kamook

Reputation: 49

using Scapy to divide SCTP chunks

i am trying to use Scapy to divide a SCTP packet,but i can only divive a packet into different layers. how can i divide SCTP into different chunks? for example,using show() in Scapy, i know there are 2 chunks in SCTP,but i dnt know how to get these two chunks. two chunks in SCTP packet

Is there any ways to divide chunks in the same layer? or can i store the information from show() into an array? Thanks^^

SCTP packet structure

Upvotes: 0

Views: 1469

Answers (1)

relet
relet

Reputation: 7009

You should be able to traverse the chunks the same way you traverse the layers.

With a method like:

def expand(pkt):                                                                
    payload = []                                                                
    for p in pkt.payload:                                                       
        payload+=expand(p)                                                      
    return [pkt.name, payload]    

print(expand(pkt))                                                      
print(pkt.payload.payload.payload.name)

I get, for an SCTP package:

['Ethernet', ['IP', ['SCTP', ['SCTPChunkSACK', []]]]]
SCTPChunkSACK

edit: For the content:

>>> print(pkt[SCTP][1])                                                     

b'\x03\x00\x00\x10\x7f\x8cD\x18\x00\x01\xa0\x00\x00\x00\x00\x00'

>>> print(pkt[SCTP][1].show())   

###[ SCTPChunkSACK ]###
  type      = sack
  flags     = 0x0
  len       = 16
  cumul_tsn_ack= 0x7f8c4418
  a_rwnd    = 106496
  n_gap_ack = 0
  n_dup_tsn = 0
  gap_ack_list= []
  dup_tsn_list= []

So you already have your (nested) list of chunks at pkt[SCTP][1:].

Upvotes: 1

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