pySim-trace: Add support for reading GSMTAP from pcap files

So far we supported
* GSMTAP live traces via a UDP socket
* RSPRO traces from pcap files (or live)

We were lacking support for reading GSMTAP stored in pcap, which
is what this patch implements.

Change-Id: I46d42774b39a2735500ff5804206ddcfa545568c
Harald Welte 2022-12-02 22:50:35 +01:00
parent 284ac104af
commit c95f6e2124
2 changed files with 98 additions and 0 deletions

View File

@ -18,6 +18,7 @@ from pySim.transport import LinkBase
from pySim.apdu_source.gsmtap import GsmtapApduSource
from pySim.apdu_source.pyshark_rspro import PysharkRsproPcap, PysharkRsproLive
from pySim.apdu_source.pyshark_gsmtap import PysharkGsmtapPcap
from pySim.apdu.ts_102_221 import UiccSelect, UiccStatus
@ -130,6 +131,11 @@ parser_gsmtap.add_argument('-i', '--bind-ip', default='',
parser_gsmtap.add_argument('-p', '--bind-port', default=4729,
help='Local UDP port')
parser_gsmtap_pyshark_pcap = subparsers.add_parser('gsmtap-pyshark-pcap', help="""
PCAP file containing GSMTAP (SIM APDU) communication; processed via pyshark.""")
parser_gsmtap_pyshark_pcap.add_argument('-f', '--pcap-file', required=True,
help='Name of the PCAP[ng] file to be read')
parser_rspro_pyshark_pcap = subparsers.add_parser('rspro-pyshark-pcap', help="""
PCAP file containing RSPRO (osmo-remsim) communication; processed via pyshark.
@ -153,6 +159,8 @@ if __name__ == '__main__':
s = PysharkRsproPcap(opts.pcap_file)
elif opts.source == 'rspro-pyshark-live':
s = PysharkRsproLive(opts.interface)
elif opts.source == 'gsmtap-pyshark-pcap':
s = PysharkGsmtapPcap(opts.pcap_file)
tracer = Tracer(source=s, suppress_status=opts.suppress_status, suppress_select=opts.suppress_select)'Entering main loop...')

View File

@ -0,0 +1,90 @@
# coding=utf-8
# (C) 2022 by Harald Welte <>
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <>.
import sys
import logging
from pprint import pprint as pp
from typing import Tuple
import pyshark
from pySim.utils import h2b, b2h
from pySim.apdu import Tpdu
from pySim.gsmtap import GsmtapMessage
from . import ApduSource, PacketType, CardReset
from pySim.apdu.ts_102_221 import ApduCommands as UiccApduCommands
from pySim.apdu.ts_31_102 import ApduCommands as UsimApduCommands
from pySim.apdu.global_platform import ApduCommands as GpApduCommands
ApduCommands = UiccApduCommands + UsimApduCommands + GpApduCommands
logger = logging.getLogger(__name__)
class _PysharkGsmtap(ApduSource):
"""APDU Source [provider] base class for reading GSMTAP SIM APDU via tshark."""
def __init__(self, pyshark_inst):
self.pyshark = pyshark_inst
self.bank_id = None
self.bank_slot = None
self.cmd_tpdu = None
def read_packet(self) -> PacketType:
p =
return self._parse_packet(p)
def _set_or_verify_bank_slot(self, bsl: Tuple[int, int]):
"""Keep track of the bank:slot to make sure we don't mix traces of multiple cards"""
if not self.bank_id:
self.bank_id = bsl[0]
self.bank_slot = bsl[1]
if self.bank_id != bsl[0] or self.bank_slot != bsl[1]:
raise ValueError('Received data for unexpected B(%u:%u)' % (bsl[0], bsl[1]))
def _parse_packet(self, p) -> PacketType:
udp_layer = p['udp']
udp_payload_hex = udp_layer.get_field('payload').replace(':','')
gsmtap = GsmtapMessage(h2b(udp_payload_hex))
gsmtap_msg = gsmtap.decode()
if gsmtap_msg['type'] != 'sim':
raise ValueError('Unsupported GSMTAP type %s' % gsmtap_msg['type'])
sub_type = gsmtap_msg['sub_type']
if sub_type == 'apdu':
return ApduCommands.parse_cmd_bytes(gsmtap_msg['body'])
elif sub_type == 'atr':
# card has been reset
return CardReset()
elif sub_type in ['pps_req', 'pps_rsp']:
# simply ignore for now
raise ValueError('Unsupported GSMTAP-SIM sub-type %s' % sub_type)
class PysharkGsmtapPcap(_PysharkGsmtap):
"""APDU Source [provider] class for reading GSMTAP from a PCAP
file via pyshark, which in turn uses tshark (part of wireshark).
def __init__(self, pcap_filename):
pcap_filename: File name of the pcap file to be opened
pyshark_inst = pyshark.FileCapture(pcap_filename, display_filter='gsm_sim', use_json=True, keep_packets=False)