mavtcpsniff.py

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#!/usr/bin/env python

'''
connect as a client to two tcpip ports on localhost with mavlink packets.    pass them both directions, and show packets in human-readable format on-screen.

this is useful if
* you have two SITL instances you want to connect to each other and see the comms.
* you have any tcpip based mavlink happening, and want something better than tcpdump

hint:
* you can use netcat/nc to do interesting redorection things with each end if you want to.

Copyright Sept 2012 David "Buzz" Bussenschutt
Released under GNU GPL version 3 or later
'''

import sys, time, os, struct

from pymavlink import mavutil
#from pymavlink import mavlinkv10 as mavlink

from argparse import ArgumentParser
parser = ArgumentParser(description=__doc__)
parser.add_argument("srcport", type=int)
parser.add_argument("dstport", type=int)

args = parser.parse_args()

msrc = mavutil.mavlink_connection('tcp:localhost:{}'.format(args.srcport), planner_format=False,
                                  notimestamps=True,
                                  robust_parsing=True)

mdst = mavutil.mavlink_connection('tcp:localhost:{}'.format(args.dstport), planner_format=False,
                                  notimestamps=True,
                                  robust_parsing=True)


# simple basic byte pass through, no logging or viewing of packets, or analysis etc
#while True:
#  # L -> R
#    m = msrc.recv();
#    mdst.write(m);
#  # R -> L
#    m2 = mdst.recv();
#    msrc.write(m2);


# similar to the above, but with human-readable display of packets on stdout.
# in this use case we abuse the self.logfile_raw() function to allow
# us to use the recv_match function ( whch is then calling recv_msg ) , to still get the raw data stream
# which we pass off to the other mavlink connection without any interference.
# because internally it will call logfile_raw.write() for us.

# here we hook raw output of one to the raw input of the other, and vice versa:
msrc.logfile_raw = mdst
mdst.logfile_raw = msrc

while True:
  # L -> R
    l = msrc.recv_match();
    if l is not None:
       l_last_timestamp = 0
       if  l.get_type() != 'BAD_DATA':
           l_timestamp = getattr(l, '_timestamp', None)
           if not l_timestamp:
               l_timestamp = l_last_timestamp
           l_last_timestamp = l_timestamp

       print("--> %s.%02u: %s\n" % (
           time.strftime("%Y-%m-%d %H:%M:%S",
                         time.localtime(l._timestamp)),
           int(l._timestamp*100.0)%100, l))

  # R -> L
    r = mdst.recv_match();
    if r is not None:
       r_last_timestamp = 0
       if r.get_type() != 'BAD_DATA':
           r_timestamp = getattr(r, '_timestamp', None)
           if not r_timestamp:
               r_timestamp = r_last_timestamp
           r_last_timestamp = r_timestamp

       print("<-- %s.%02u: %s\n" % (
           time.strftime("%Y-%m-%d %H:%M:%S",
                         time.localtime(r._timestamp)),
           int(r._timestamp*100.0)%100, r))