René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"metrics: negative byte counts from 32-bit wrap of 64-bit counters and counter resets","articleBody":"## Summary\n\nTelemetry shows negative byte counts. Samos (BB7ZJW5MWK2TFJ) showed −2.0 GB of Wi-Fi on 17 Sep, and −5.35 GB across 7 LTE samples between 21 Sep and 11 Oct. Download graphs therefore under-read.\n\n## Cause\n\n- **32-bit wrap:** `fix_underflow` subtracts 2^32 from any value over INT32_MAX ([radio.lua#L43-L48](https://github.com/jangala-dev/devicecode-lua/blob/a9691b9e2e6d43bf8631b0ab08bdbbe14fa6674b/src/services/hal/drivers/radio.lua#L43-L48)). It is also applied to per-station `tx_bytes`/`rx_bytes` ([radio.lua#L407-L414](https://github.com/jangala-dev/devicecode-lua/blob/a9691b9e2e6d43bf8631b0ab08bdbbe14fa6674b/src/services/hal/drivers/radio.lua#L407-L414)), which are 64-bit, so any counter past 2 GiB goes negative.\n- **No reset handling:** `DeltaValue:run` returns `value - last_val` without handling a counter reset ([processing.lua#L201-L211](https://github.com/jangala-dev/devicecode-lua/blob/a9691b9e2e6d43bf8631b0ab08bdbbe14fa6674b/src/services/metrics/processing.lua#L201-L211)). After a `wifi reload` or interface restart, the next delta is minus the old total. This predates v0.11, but v0.11 reloads more often.\n\n## Fix\n\n- Apply `fix_underflow` only to signed 32-bit fields (signal, noise, txpower, channel).\n- In `DeltaValue`, treat a value lower than the last one as a reset: report the new value, or skip that sample.\n","author":{"url":"https://github.com/cpunt","@type":"Person","name":"cpunt"},"datePublished":"2026-10-29T15:03:59Z","url":"https://github.com/jangala-dev/devicecode-lua/issues/353"}