Cort BuffingtonandClaude Opus 5
3fa1b32f16
An XLX system is a MODE: OUTBOUND system with an XLX_MODULE letter set. XLX's
DMR interface is the homebrew protocol unmodified -- DMRGateway uses the same
CDMRNetwork class for XLX and BrandMeister, and there are no XLX conditionals in
its network layer -- so this adds no new mode, subclass, or data path. The only
protocol difference is one in-band private call at connect that selects the
module, plus pinning the connection to TS2/TG9.
Module binding is static by design. Runtime or end-user module selection would
break the nailed-up systems/bridges model; DMRGateway is the right tool for
user-selectable modules at a repeater or hotspot.
TS2/TG9 is injected by expand_xlx_bridges rather than read from rules.py, so
XLX_BRIDGES is a flat {system: bridge} map with no TS or TGID column. This is
not a default -- it makes a wrong value inexpressible. That matters more here
than elsewhere because every XLX failure is silent: the reflector never
acknowledges a link, and no frame on the wire carries a module identity, so a
mistyped talkgroup would leave HBlink looking healthy while traffic vanished.
The existing conference-bridge retarget path already rewrites the header dst,
flips the slot bit, and regenerates the full and embedded LC, so no XLX-specific
rewrite code is needed -- an XLX system is just a bridge member with a fixed
TS/TGID.
An XLX system in UNIT is a startup error. Reflector module selection *is* a
private call to 4001-4026, so forwarding a unit call to one could silently move
the reflector into a different room for every user connected to it.
Behaviour verified against xlxd source (src/cdmrmmdvmprotocol.cpp):
* Five acceptance gates at :636-655, each of which silently drops the packet:
exactly 55 bytes, DATA_SYNC frame type, TS2, slot type VOICE_LC_HEADER, and
a valid BS/MS data sync. The 55-byte requirement is why the packet carries
two trailing pad bytes; a bare 53-byte DMRD is rejected.
* Only the three header frames are parsed for the link command; the two
terminators have slot type 2 and are ignored, but are sent to frame the call.
* Unlink-then-link is required, not defensive. At :297-325 a link naming a
different module while already linked is discarded and rewritten to the
module already held, so a reconnect that skipped the unlink would silently
stay in the previous room.
* xlxd reads the destination from DMRD header bytes 8-10 and never decodes the
LC (its BPTC decode is commented out at :657-660). The LC is still built
honestly from the same src/dst: a packet whose payload contradicts its header
is a debugging trap for anything that does decode it.
Note that a stock xlxd is built with NB_OF_MODULES = 10, so only modules A-J
exist unless the operator rebuilt it. A-Z is accepted here since the protocol
allows it, but an absent module produces no link and no error.
tests/test_xlx_link.py adds 35 tests: the acceptance gates transcribed from
xlxd's parser, packet structure, XLX_BRIDGES expansion and its guards, and
XLX_MODULE validation. One test reproduces the canned bursts from the 2019
reference implementation byte for byte, from their own decoded src/dst and
colour code, which pins the burst builder against six years of field-proven
behaviour.
No new dependencies: bitarray and dmr_utils3 were already required.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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1.4 KiB
Tests
Regression tests pinning the behavior of helpers extracted during the 2026 cleanup. They exist because a live OBP/HBP network with real DMR audio cannot be reproduced in a dev environment, so the routing helpers are validated in isolation instead.
test_acl.py—HBSYSTEM.dmrd_acl_check()(the shared master/peer ACL logic): PERMIT/DENY matching, per-timeslot scoping, and the once-per-stream drop logging.test_lc.py—gen_lcs()andembed_lc()frombridge.py: Link Control generation and the DMR payload LC rewrite used by all four group-routing paths.test_xlx_link.py— the XLX reflector module link: packet construction (send_xlx_link/xlx_link_module),expand_xlx_bridges()and its guards, andXLX_MODULEconfig validation. The acceptance gates asserted here are transcribed from xlxd's own parser, because a reflector never acknowledges a link and puts no module identity on the wire — a malformed packet is silently discarded, so there is no runtime signal to fall back on. One test reproduces the field-proven 2019 reference bursts byte for byte.
Running
From the repo root, using the project virtualenv (which has twisted,
dmr_utils3, and bitarray):
venv/bin/python -m unittest discover -s tests -v
Pure stdlib unittest — no extra dependencies. They also run under pytest if
you have it installed (venv/bin/python -m pytest tests).