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
diff --git a/pySim/apdu_source/pyshark_gsmtap.py b/pySim/apdu_source/pyshark_gsmtap.py
new file mode 100644
index 0000000..8ea9ae7
--- /dev/null
+++ b/pySim/apdu_source/pyshark_gsmtap.py
@@ -0,0 +1,90 @@
+# coding=utf-8
+
+# (C) 2022 by Harald Welte <laforge@osmocom.org>
+#
+# 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
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# 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 <http://www.gnu.org/licenses/>.
+
+
+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
+ super().__init__()
+
+ def read_packet(self) -> PacketType:
+ p = self.pyshark.next()
+ 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]
+ else:
+ 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
+ pass
+ else:
+ 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):
+ """
+ Args:
+ 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)
+ super().__init__(pyshark_inst)
+