100 lines
3.5 KiB
Python
100 lines
3.5 KiB
Python
|
#!/usr/bin/env python3
|
||
|
|
#
|
||
|
|
# Copyright (c) 2022, The OpenThread Authors.
|
||
|
|
# All rights reserved.
|
||
|
|
#
|
||
|
|
# Redistribution and use in source and binary forms, with or without
|
||
|
|
# modification, are permitted provided that the following conditions are met:
|
||
|
|
# 1. Redistributions of source code must retain the above copyright
|
||
|
|
# notice, this list of conditions and the following disclaimer.
|
||
|
|
# 2. Redistributions in binary form must reproduce the above copyright
|
||
|
|
# notice, this list of conditions and the following disclaimer in the
|
||
|
|
# documentation and/or other materials provided with the distribution.
|
||
|
|
# 3. Neither the name of the copyright holder nor the
|
||
|
|
# names of its contributors may be used to endorse or promote products
|
||
|
|
# derived from this software without specific prior written permission.
|
||
|
|
#
|
||
|
|
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
||
|
|
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||
|
|
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||
|
|
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
|
||
|
|
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||
|
|
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
||
|
|
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
||
|
|
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
||
|
|
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
||
|
|
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||
|
|
# POSSIBILITY OF SUCH DAMAGE.
|
||
|
|
#
|
||
|
|
""" Module to provide codec utilities for .pcap formatters. """
|
||
|
|
|
||
|
|
import struct
|
||
|
|
import time
|
||
|
|
|
||
|
|
# https://www.tcpdump.org/linktypes.html
|
||
|
|
DLT_IEEE802_15_4_WITHFCS = 195
|
||
|
|
|
||
|
|
PCAP_MAGIC_NUMBER = 0xA1B2C3D4
|
||
|
|
PCAP_VERSION_MAJOR = 2
|
||
|
|
PCAP_VERSION_MINOR = 4
|
||
|
|
|
||
|
|
|
||
|
|
class PcapCodec(object):
|
||
|
|
""" Utility class for .pcap formatters. """
|
||
|
|
|
||
|
|
def __init__(self, filename, channel):
|
||
|
|
self._dlt = DLT_IEEE802_15_4_WITHFCS
|
||
|
|
if not filename.endswith('.pcap'):
|
||
|
|
raise ValueError('Filename should end with .pcap')
|
||
|
|
self._pcap_file = open(filename, 'wb')
|
||
|
|
self._pcap_file.write(self.encode_header())
|
||
|
|
self._channel = channel
|
||
|
|
|
||
|
|
def encode_header(self):
|
||
|
|
""" Return a pcap file header. """
|
||
|
|
return struct.pack(
|
||
|
|
'<LHHLLLL',
|
||
|
|
PCAP_MAGIC_NUMBER,
|
||
|
|
PCAP_VERSION_MAJOR,
|
||
|
|
PCAP_VERSION_MINOR,
|
||
|
|
0,
|
||
|
|
0,
|
||
|
|
256,
|
||
|
|
self._dlt,
|
||
|
|
)
|
||
|
|
|
||
|
|
def encode_frame(self, frame, sec, usec):
|
||
|
|
""" Return a pcap encapsulation of the given frame. """
|
||
|
|
|
||
|
|
# Ignore the first byte storing channel.
|
||
|
|
frame = frame[1:]
|
||
|
|
|
||
|
|
length = len(frame)
|
||
|
|
pcap_frame = struct.pack('<LLLL', sec, usec, length, length)
|
||
|
|
pcap_frame += frame
|
||
|
|
return pcap_frame
|
||
|
|
|
||
|
|
def _get_timestamp(self):
|
||
|
|
""" Return the internal timestamp. """
|
||
|
|
timestamp = time.time()
|
||
|
|
timestamp_sec = int(timestamp)
|
||
|
|
timestamp_usec = int((timestamp - timestamp_sec) * 1000000)
|
||
|
|
return timestamp_sec, timestamp_usec
|
||
|
|
|
||
|
|
def append(self, frame):
|
||
|
|
""" Append a frame. """
|
||
|
|
|
||
|
|
# Filter channel.
|
||
|
|
if frame[0] != self._channel:
|
||
|
|
return
|
||
|
|
|
||
|
|
timestamp = self._get_timestamp()
|
||
|
|
pkt = self.encode_frame(frame, *timestamp)
|
||
|
|
self._pcap_file.write(pkt)
|
||
|
|
self._pcap_file.flush()
|
||
|
|
|
||
|
|
def close(self):
|
||
|
|
""" Close the pcap file. """
|
||
|
|
|
||
|
|
self._pcap_file.close()
|