catarrh
73b0277ef7
Python-based SIMtrace2 sniffer — drop-in replacement for simtrace2-sniff. Single dependency (pyusb), auto-reconnect, GSMTAP/PCAP output, library API. Modules: protocol.py — SIMtrace2 USB sniffing protocol parser device.py — USB discovery + SniffSession with exponential backoff reconnect gsmtap.py — GSMTAP UDP sender for Wireshark pcap.py — PCAP file writer (LINKTYPE_GSMTAP) dump.py — hex dump formatters + file output __main__.py — CLI entry point Startup script sniff-start.sh handles udev permission checks and shows install instructions. udev rule uses TAG+=uaccess (systemd-logind ACL).
94 lines
2.9 KiB
Markdown
94 lines
2.9 KiB
Markdown
# simtrace2-pysniff
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Python-based replacement for `simtrace2-sniff` — SIM card communication sniffer
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for Osmocom SIMtrace2 hardware (firmware in trace mode).
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**Single dependency**: PyUSB (libusb wrapper). No libosmocore, no libosmosim.
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## Quick Start
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```sh
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# Install + run
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pip install pyusb
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python -m simtrace2_pysniff
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```
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Or use the bundled startup script:
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```sh
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./sniff-start.sh # hex dump to stdout
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./sniff-start.sh --gsmtap 127.0.0.1:4729 # + Wireshark GSMTAP
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./sniff-start.sh --pcap trace.pcap # save PCAP for later
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./sniff-start.sh --inactivity-timeout 30 # reconnect on silence
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```
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The startup script performs a pre-flight USB permission check and prints
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install instructions if the udev rule is missing (see below).
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## USB Device Access
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### Linux
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A udev rule is required for non-root USB access to the SIMtrace2 device.
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```sh
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sudo cp 70-simtrace2-pysniff.rules /etc/udev/rules.d/
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sudo udevadm control --reload-rules
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sudo udevadm trigger
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```
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Then reconnect the SIMtrace2 USB cable. The rule uses `TAG+="uaccess"`
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(systemd-logind ACL) — no group membership or world-writable permissions needed.
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### Windows
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Windows does not ship a libusb-compatible driver for SIMtrace2. Use
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[Zadig](https://zadig.akeo.ie/) to replace the default driver:
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1. Download and run **Zadig**
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2. Plug in the SIMtrace2 device
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3. Select it in the dropdown (VID `1D50`, PID `60E3` — "Osmocom SIMtrace 2")
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4. Choose **WinUSB** (or libusbK) as the replacement driver
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5. Click **Replace Driver** (one-time operation)
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After that, `python -m simtrace2_pysniff` works identically to Linux.
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## CLI Options
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```
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python -m simtrace2_pysniff [OPTIONS]
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--gsmtap HOST[:PORT] Send ATR/TPDU as GSMTAP over UDP (default port 4729)
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--pcap FILE Write sniffed data to PCAP file for Wireshark
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--output, -o FILE Write hex dump to file
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--no-stdout Suppress hex dump to stdout
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--vendor HEX USB vendor ID (default: 0x1d50)
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--product HEX USB product ID (default: auto-detect)
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Recovery options:
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--no-reconnect Exit on USB disconnect instead of reconnecting
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--inactivity-timeout SEC Reconnect after N seconds of silence (default: disabled)
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```
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## Library Usage
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```python
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from simtrace2_pysniff import SniffSession
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session = SniffSession(inactivity_timeout=30.0)
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for msg in session.iter_messages():
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print(f"{msg.type}: {msg.data.hex()}")
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```
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## Output
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- **stdout**: `ATR: 3b 9e ...`, `TPDU: a0 a4 00 00 02 3f 00`, `Card state change: reset de-asserted`
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- **GSMTAP**: ATR (subtype 1) and TPDU (subtype 2) over UDP to Wireshark
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- **PCAP**: all messages as GSMTAP-encapsulated packets (LINKTYPE 155), openable in Wireshark
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## Recovery
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The tool survives hardware resets, cable disconnects, and firmware hangs
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by default — it reconnects with exponential backoff (1s → 30s cap).
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Use `--inactivity-timeout` to also trigger reconnect on silent firmware hangs.
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