wifi : network failure when one of several wifi clients disconnects (IDFGH-2997)

[seppf]

Environment

• Development Kit: ESP32-Ethernet-Kit
• Kit version: v1.1
• Module or chip used: ESP32-WROVER-IB
• IDF version: v4.2-dev-701-g0ae960f2f
• Build System: CMake
• Compiler version: xtensa-esp32-elf-gcc (crosstool-NG esp-2019r2) 8.2.0
• Operating System: Windows
• (Windows only) environment type: Plain Command Prompt
• Using an IDE?: Yes (Eclipse Plugin)
• Power Supply: [USB]

Problem Description

We have been testing wifi and wifi to ethernet bridging using the eth2ap code sample (wifi in AP mode).
Testing connectivity with two or more stations connected (stations mutually pinging themselves and the gateway on the ethernet) we have observed the following issue:
When one of those station is disconnected (e.g. by manually disabling wifi on that station or roaming to a different AP), all stations on the esp32 access point loose connectivity (mutual and to gateway). So no packets are transported any more. In the terminal log of esp32 only the disconnected station is logged ("leave"). There is no event logged of any status change of the other stations.

Network connectivity is restored by either:
A. connecting the disconnected station again (!!!)
B. reconnecting (authenticate+associate) the other stations (e.g. be toggling wifi off / on)
C. rebooting the esp32 - which in consequence leeds to a reconnection of the stations presumably caused by the beacon sequence number being reset.

B. + C. obviously just restore the network connection from plain disconnnected state.
A. is the most interesting case as it seems to indicate an issue in the wifi driver of esp32.

We have also traced the 802.11 packets on the air. In case of erroneous disconnectivity the esp32 module does not send dis-assoc or de-auth frames to the stations as a response to any of the packets of the stations arriving. So at that level the esp32 treats the stations as being connected (i.e. still authenticated and associated).

Expected Behavior

Actual Behavior

Steps to reproduce

see above.

Code to reproduce this issue

esp-idf code sample eth2ap

Any ideas how to solve that issue?

Best Regards, Josef

[Alvin1Zhang]

@seppf Thanks for reporting, we noticed the issue and already have a fix internally now under reviewing, will update once it is available on GitHub. Thanks.

[seppf]

Hi Alvin,
thanks for taking care!