tools/generate_cbor_pcap.py

   1 #!/usr/bin/env python3
   2 '''
   3 Convert a CBOR diagnostic notation file into an HTTP request
   4 for the encoded cbor.
   5 This allows straightforward test and debugging of simple pcap files.
   6
   7  Copyright 2021 Brian Sipos <brian.sipos@gmail.com>
   8
   9 SPDX-License-Identifier: LGPL-2.1-or-later
  10 '''
  11
  12 from argparse import ArgumentParser
  13 from io import BytesIO
  14 import scapy
  15 from scapy.layers.l2 import Ether
  16 from scapy.layers.inet import IP, TCP
  17 from scapy.layers.http import HTTP, HTTPRequest
  18 from scapy.packet import Raw
  19 from scapy.utils import wrpcap
  20 from subprocess import check_output
  21 import sys
  22
  23
  24 def main():
  25     parser = ArgumentParser()
  26     parser.add_argument('--content-type', default='application/cbor',
  27                         help='The request content-type header')
  28     parser.add_argument('--infile', default='-',
  29                         help='The diagnostic text input file, or "-" for stdin')
  30     parser.add_argument('--outfile', default='-',
  31                         help='The PCAP output file, or "-" for stdout')
  32     parser.add_argument('--intype', default='cbordiag',
  33                         choices=['cbordiag', 'raw'],
  34                         help='The input data type.')
  35     args = parser.parse_args()
  36
  37     # First get the CBOR data itself
  38     infile_name = args.infile.strip()
  39     if infile_name != '-':
  40         infile = open(infile_name, 'rb')
  41     else:
  42         infile = sys.stdin.buffer
  43
  44     if args.intype == 'raw':
  45         cbordata = infile.read()
  46     elif args.intype == 'cbordiag':
  47         cbordata = check_output('diag2cbor.rb', stdin=infile)
  48
  49     # Now synthesize an HTTP request with that body
  50     req = HTTPRequest(
  51         Method='POST',
  52         Host='example.com',
  53         User_Agent='scapy',
  54         Content_Type=args.content_type,
  55         Content_Length=str(len(cbordata)),
  56     ) / Raw(cbordata)
  57
  58     # Write the request directly into pcap
  59     outfile_name = args.outfile.strip()
  60     if outfile_name != '-':
  61         outfile = open(outfile_name, 'wb')
  62     else:
  63         outfile = sys.stdout.buffer
  64
  65     pkt = Ether()/IP()/TCP()/HTTP()/req
  66     wrpcap(outfile, pkt)
  67
  68 if __name__ == '__main__':
  69     sys.exit(main())