Skip to content

ADR-060-provision-channel-mac-filter.md

Latest commit

 

History

History
59 lines (45 loc) · 2.41 KB

ADR-060-provision-channel-mac-filter.md

File metadata and controls

59 lines (45 loc) · 2.41 KB
Raw

ADR-060: Provision Channel Override and MAC Address Filtering

  • Status: Accepted
  • Date: 2026-03-12
  • Issues: #247, #229

Context

Two related provisioning gaps were reported by users:

  1. Channel mismatch (Issue #247): The CSI collector initializes on the Kconfig default channel (typically 6), even when the ESP32 connects to an AP on a different channel (e.g. 11). On managed networks where the user cannot change the router channel, this makes nodes undiscoverable. The provision.py script has no --channel argument.

  2. Missing MAC filter (Issue #229): The v0.2.0 release notes documented a --filter-mac argument for provision.py, but it was never implemented. The firmware's CSI callback accepts frames from all sources, causing signal mixing in multi-AP environments.

Decision

Channel configuration

  • Add --channel argument to provision.py that writes a csi_channel key (u8) to NVS.
  • In nvs_config.c, read the csi_channel key and override channel_list[0] when present.
  • In csi_collector_init(), after WiFi connects, auto-detect the AP channel via esp_wifi_sta_get_ap_info() and use it as the default CSI channel when no NVS override is set. This ensures the CSI collector always matches the connected AP's channel without requiring manual provisioning.

MAC address filtering

  • Add --filter-mac argument to provision.py that writes a filter_mac key (6-byte blob) to NVS.
  • In nvs_config.h, add a filter_mac[6] field and filter_mac_set flag.
  • In nvs_config.c, read the filter_mac blob from NVS.
  • In the CSI callback (wifi_csi_callback), if filter_mac_set is true, compare the source MAC from the received frame against the configured MAC and drop non-matching frames.

Provisioning flow

python provision.py --port COM7 --channel 11
python provision.py --port COM7 --filter-mac "AA:BB:CC:DD:EE:FF"
python provision.py --port COM7 --channel 11 --filter-mac "AA:BB:CC:DD:EE:FF"

Consequences

  • Users on managed networks can force the CSI channel to match their AP
  • Multi-AP environments can filter CSI to a single source
  • Auto-channel detection eliminates the most common misconfiguration
  • Backward compatible: existing provisioned nodes without these keys behave as before (use Kconfig default channel, accept all MACs)