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).
kamilkrzywda