Files
simtrace-analyser/simtrace2_pysniff/gsmtap.py
T
catarrh 7eaf7e9b53 Decode sigrok-iso7816-stream RST/VCC line events (GSMTAP 0x10/0x11)
Support the sigrok-iso7816-stream decoder (FX2 logic-analyzer passive
SIM sniffer, github.com/anttro/sigrok_iso7816_stream) which streams
GSMTAP-SIM on UDP 4729 and adds two custom sub-types for line events.

- gsmtap.py: GSMTAP_SIM_RST_EVENT (0x10) / GSMTAP_SIM_VCC_EVENT (0x11).
- capture.py: gsmtap_msg_type() maps 0x10→'rst', 0x11→'vcc' (shared by
  the listener and tests); pcap.py _SUB_TYPE_NAMES gains the same
  entries so PCAP re-imports of these captures preserve the events.
- decode.py: decode_line_event() decodes [direction, level, reserved]
  into reset asserted/de-asserted or power applied/removed + level;
  routed through decode_sniff_msg.
- database.py: reset-assert and power-removal invalidate the per-channel
  file selection (card-level transition); de-assert / power-on are
  markers only.
- frontend: RST/VCC labels (RESET ASSERTED / VCC OFF, …), a detail-view
  branch (Event + Level + raw), and list styling (.apdu-type.rst/.vcc).

README notes the custom sub-type compatibility. Tests: +8 (line-event
vectors, sniff routing, subtype + PCAP round-trip mappings) — 359
total. Version 1.21.0, SW cache simtrace-analyser-v31.
2026-08-26 17:29:36 +03:00

106 lines
3.3 KiB
Python

"""GSMTAP UDP sender for Wireshark integration.
GSMTAP header format (big-endian, 16 bytes). Based on libosmocore's gsmtap.h.
"""
import struct
import socket
GSMTAP_VERSION = 0x02
GSMTAP_HDR_LEN = 4 # in 32-bit words (16 bytes)
GSMTAP_TYPE_SIM = 0x04
GSMTAP_SIM_APDU = 0x00
GSMTAP_SIM_ATR = 0x01
GSMTAP_SIM_PPS_REQ = 0x02
GSMTAP_SIM_PPS_RSP = 0x03
# Custom sub-types from the sigrok-iso7816-stream decoder
# (github.com/anttro/sigrok_iso7816_stream): line-level events.
GSMTAP_SIM_RST_EVENT = 0x10
GSMTAP_SIM_VCC_EVENT = 0x11
GSMTAP_UDP_PORT = 4729
_GSMTAP_HDR_FMT = '!BBBBHBBIBBBB' # 16 bytes, big-endian
_GSMTAP_HDR_SIZE = struct.calcsize(_GSMTAP_HDR_FMT)
def build_gsmtap_packet(sub_type, data, slot_nr=0):
"""Build a GSMTAP packet as bytes.
Returns *gsmtap_hdr* + *data* as a single bytes object.
"""
hdr = struct.pack(
_GSMTAP_HDR_FMT,
GSMTAP_VERSION, # version
GSMTAP_HDR_LEN, # hdr_len (in 32-bit words)
GSMTAP_TYPE_SIM, # type
0, # timeslot
0, # arfcn
0, # noise_db
0, # signal_db
0, # frame_number
sub_type, # sub_type
0, # antenna_nr
slot_nr, # sub_slot
0, # res
)
return hdr + data
class GsmtapSender:
"""Send ATR/APDU data as GSMTAP UDP packets."""
def __init__(self, host='127.0.0.1', port=GSMTAP_UDP_PORT):
self._addr = (host, port)
self._sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
def send_atr(self, data, slot_nr=0):
packet = build_gsmtap_packet(GSMTAP_SIM_ATR, data, slot_nr)
self._sock.sendto(packet, self._addr)
def send_apdu(self, data, slot_nr=0):
packet = build_gsmtap_packet(GSMTAP_SIM_APDU, data, slot_nr)
self._sock.sendto(packet, self._addr)
def close(self):
self._sock.close()
class GsmtapReceiver:
"""Receive GSMTAP-SIM packets over UDP (compatible with simtrace2-sniff)."""
def __init__(self, bind_ip='127.0.0.1', bind_port=GSMTAP_UDP_PORT):
self._sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self._sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._sock.bind((bind_ip, bind_port))
self._sock.settimeout(1.0)
def read_packet(self):
"""Block until a GSMTAP-SIM packet arrives.
Returns ``(sub_type, data)`` on success or ``(None, None)``
on timeout. *sub_type* is ``GSMTAP_SIM_ATR`` or ``GSMTAP_SIM_APDU``.
Raises ``ValueError`` for non-SIM or unknown GSMTAP packets.
"""
try:
packet, addr = self._sock.recvfrom(65536)
except (socket.timeout, OSError):
return None, None
if len(packet) < _GSMTAP_HDR_SIZE:
raise ValueError(f'GSMTAP packet too short: {len(packet)} bytes')
(version, hdr_len, pkt_type, _timeslot, _arfcn, _noise, _signal,
_frame, sub_type, _antenna, sub_slot, _res) = \
struct.unpack(_GSMTAP_HDR_FMT, packet[:_GSMTAP_HDR_SIZE])
if pkt_type != GSMTAP_TYPE_SIM:
raise ValueError(f'Not a GSMTAP SIM packet (type={pkt_type})')
data = packet[_GSMTAP_HDR_SIZE:]
return sub_type, data
def close(self):
self._sock.close()