refactor(dpi/mqtt): include UNSUBSCRIBE in flag-validation match#294
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domcyrus merged 1 commit intoMay 20, 2026
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The flag-validation block in `is_mqtt_packet` listed UNSUBSCRIBE(10)
in the inner expected-flag table (`8 | 10 => 0x02`) but not in the
outer match arm, so packet type 10 never reached the inner table and
its required `0x02` flag bit was never checked. The fall-through
arm's comment ("PUBLISH(3), PUBREC(5) — flags carry DUP/QoS/RETAIN")
was inadvertently also accepting UNSUBSCRIBE despite that not being
the documented intent.
Add 10 to the outer match so the validation actually applies, and
reformat the inline comment so each entry has a single source of
truth. `is_mqtt_packet` still only returns true for CONNECT (the
only packet type with a port-independent signature), so this change
is invariant-preserving — it removes an unreachable branch and
restores the stated MQTT §2.1.2 invariant for callers that may later
relax that gate.
Owner
|
@obchain thanks a lot also for this PR. LGTM! |
This was referenced May 21, 2026
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Summary
Adds
10(UNSUBSCRIBE) to the outermatcharm inis_mqtt_packet(src/network/dpi/mqtt.rs:19) so the inner8 | 10 => 0x02flag-validation rule actually runs for that packet type.Closes #293.
Why
The outer arm previously listed
1 | 2 | 4 | 6 | 7 | 8 | 9 | 11 | 12 | 13 | 14— note 10 missing. UNSUBSCRIBE fell into the_ => {}catch-all (intended for PUBLISH/PUBREC's flexible nibble), which silently accepted any flag value despite the inner table claiming UNSUBSCRIBE requires0x02. The10 => 0x02arm was unreachable.This is invariant-preserving:
is_mqtt_packetstill returns true only for CONNECT (the strong-signature gate at line 52 is unchanged), so no caller sees a behavior change today. It restores the MQTT §2.1.2 invariant the comment promises and removes a misleading unreachable arm, in the same spirit as the recentrefactor(dpi/...)cleanups (#279, #289, #290).I also reformatted the inline comment for readability — same content, one source of truth per packet type.
Test plan
cargo clippy --all-targets --all-features -- -D warnings— cleancargo fmt --check— cleancargo test --lib mqtt— 21 mqtt tests pass, no regressionscargo test --lib— full 361-test suite passes