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.
catarrh
7fd3a3c973
