The GSMTAP stream sent logical APDUs, so a receiver (SIMtrace Analyser,
Wireshark) flagged almost every packet: case-4 commands carried their Le
byte ('length_mismatch: excessive') and responses were headerless packets
decoded as bogus commands ('truncated'). The ATR also arrived in the
middle of the stream.
- gsmtap.py: the tracer now emits wire-shaped TPDUs, matching a hardware
sniffer capture: case 4 -> the command without Le plus the 61XX 'bytes
available' SW (derived from the real response length), then the data as
a GET RESPONSE TPDU (00C00000<len> + data + SW, chunked at 255); case
1/2/3 -> one packet cmd + data + SW; unparseable APDUs fall back to raw
command/response packets.
- No ATR/VCC/RST/PPS events at all (no line-level access over PC/SC);
the ATR sending helper and the server-side plumbing were removed.
- Verified by replaying the bad capture's exchanges through the new
tracer: 116 packets, zero decoder warnings (previously nearly all).
- tests: the per-case wire forms, chunking, fallbacks; README/AGENTS
document the wire shape and its limits; version 3.1.1, sw simple-v236.
Streams every APDU the server sends or receives as GSMTAP-SIM UDP packets,
so a live capture can be followed in Wireshark or the SIMtrace Analyser
without a hardware sniffer. CLI-only: --gsmtap [HOST[:PORT]], default
target 127.0.0.1:4729; no UI or API.
- pysim_simple_server/gsmtap.py: 16-byte big-endian GSMTAP-SIM header
(type 0x04, sub_type 0x00 = APDU / 0x01 = ATR) + raw APDU bytes, a
fire-and-forget non-blocking sender that never raises into card I/O, an
ApduTracer (a response is sent as data + SW1SW2, the wire form) and a
fan-out tracer. The packet layout is byte-identical to
sigrok-iso7816-stream / simtrace2-sniff (verified against the sigrok
module) and is what the analyser's GSMTAP receiver expects.
- __main__.py: --gsmtap option, tracer installed on the shared transport
before the first APDU, combined with --apdu-trace via the fan-out and
re-attached across equips (pySim nulls the tracer on every equip); one
ATR packet per equip from _apply_equipped_card/_send_gsmtap_atr.
- start.sh/start.bat: forward their extra arguments to the server, so
./start.sh --gsmtap works.
- tests: packet layout, loopback UDP delivery, tracer mapping, target
parsing, fan-out; docs (READMEs, help EN/RU, AGENTS); version 3.1.0,
sw.js simple-v235.
catarrh