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Watchdog tracks decoded frames, not raw bytes; buffer-overflow backstop (v0.21.2)
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Second production zombie slipped past v0.21.1's watchdog: text+telemetry RX
dead for >1 h while TX worked and the watchdog never fired. Root cause proven
at runtime via /proc/net/snmp — InSegs delta = 2 segments per 30 s (OutSegs 0):
the bridge peer keeps dribbling small NON-frame bytes (~every 15 s, keepalive
noise or a desynced stream) and v0.21.1 updated lastPacketAt on EVERY socket
chunk, so 'no traffic for MESH_IDLE_TIMEOUT_MS' was never true even though zero
valid Meshtastic frames decoded.

- The 'data' handler no longer updates lastPacketAt per chunk; it is updated
  only when extractFrames yields >=1 valid packet (the reset in the 'connect'
  handler is unchanged), so a stream that decodes nothing trips the watchdog
  after MESH_IDLE_TIMEOUT_MS even while raw bytes keep arriving.
- Buffer-overflow backstop: if the undecoded frame buffer exceeds
  MESH_MAX_FRAME_BUFFER (new env, default 256000) — e.g. one data event of a
  desynced stream that never forms frames — log ERROR and destroy the socket;
  the existing close -> scheduleReconnect loop self-heals it. The undecoded
  buffer is also reset on every (re)connect so leftover garbage from a dead
  session can't re-trigger the backstop or corrupt the first frames of a
  healthy new stream.

Tests: 169 -> 171 — raw non-frame bytes do NOT keep the watchdog alive
(garbage-only stream forces disconnect + reconnect, today's incident shape),
and an undecoded chunk over MESH_MAX_FRAME_BUFFER triggers destroy + a fresh
session that decodes normally (cap env-overridden to 100 since Node delivers
socket data in ~64 KB events, far below the 256_000 default).
This commit is contained in:
kamilkrzywda
2026-09-26 08:50:27 +00:00
parent 306756c63b
commit 33a88f3d83
5 changed files with 100 additions and 13 deletions
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CHANGELOG.md
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# Changelog
## v0.21.2 — 2026-09-26 08:47
- Idle watchdog now tracks DECODED FRAMES, not raw bytes (fixes a second production zombie that slipped past v0.21.1): text+telemetry RX was dead for >1 h while TX worked and the watchdog never fired — /proc/net/snmp showed InSegs delta = 2 segments per 30 s, i.e. the bridge peer keeps dribbling small NON-frame bytes (~every 15 s) that kept resetting `lastPacketAt` on every socket chunk even though zero valid Meshtastic frames decoded. The `'data'` handler no longer updates `lastPacketAt` per chunk; it is updated only when `extractFrames` yields ≥1 valid packet (the reset in the `'connect'` handler is unchanged), so a stream that decodes nothing trips the watchdog after `MESH_IDLE_TIMEOUT_MS` even while raw bytes keep arriving.
- Buffer-overflow backstop: if the undecoded frame buffer exceeds `MESH_MAX_FRAME_BUFFER` (new env, default **256000** = 250 KB) the service logs ERROR ("frame buffer overflow — stream desync, forcing reconnect") and destroys the socket → existing close→scheduleReconnect self-heals a desynced stream. The undecoded buffer is also reset on every (re)connect so leftover garbage from a dead session can't re-trigger the backstop or corrupt the first frames of a healthy new stream.
- Tests: 169 → 171 — raw non-frame bytes do NOT keep the watchdog alive (garbage-only stream forces disconnect + reconnect, exactly today's incident shape), and an undecoded chunk over `MESH_MAX_FRAME_BUFFER` triggers destroy + a fresh session that decodes normally. The existing valid-frames-reset-the-clock test now exercises frame-based tracking unchanged.
## v0.21.1 — 2026-09-26 06:47
- Bridge zombie-connection fix (production incident: outbound sends kept working ~10 h while inbound packets stopped entirely and `/api/status` stayed `connected:true`). New **idle watchdog**: the service tracks `lastPacketAt`, updated on EVERY chunk received from the bridge in the lowest-level socket `'data'` path (any frame kind, decodable or not) and reset when a connection successfully starts. A 30 s interval checks: if connected AND no inbound traffic for `MESH_IDLE_TIMEOUT_MS` (new env, default **600000** = 10 min), it logs WARN ("no bridge traffic for X ms — forcing reconnect") and destroys the socket — the EXISTING connect/retry loop (`MESH_RECONNECT_MS`) then re-establishes with a fresh sync. No changes to connect-error retry/backoff behavior; this only adds detection for established-but-silent connections.