mdns error when connect device

[nykh2010]

connectedhomeip/src/lib/dnssd/minimal_mdns/Server.cpp

Line 344 in 2dd4fdb

CHIP_ERROR lastError = CHIP_ERROR_NO_ENDPOINT;

>>> onoff toggle 0x12344321 1
[1687870707.009955][1160548:1160548] CHIP:TOO: Command: onoff toggle 0x12344321 1 
[1687870707.010566][1160548:1160550] CHIP:TOO: Sending command to node 0x12344321
[1687870707.010880][1160548:1160550] CHIP:CSM: FindOrEstablishSession: PeerId = [1:0000000012344321]
[1687870707.010907][1160548:1160550] CHIP:CSM: FindOrEstablishSession: No existing OperationalSessionSetup instance found
[1687870707.010965][1160548:1160550] CHIP:DIS: OperationalSessionSetup[1:0000000012344321]: State change 1 --> 2
[1687870707.011042][1160548:1160550] CHIP:DIS: OperationalSessionSetup[1:0000000012344321]: State change 2 --> 1
[1687870707.011071][1160548:1160550] CHIP:-: src/lib/dnssd/minimal_mdns/Server.cpp:344: CHIP Error 0x00000046: No endpoint was available to send the message at ../commands/clusters/ModelCommand.cpp:62
[1687870707.011094][1160548:1160550] CHIP:TOO: Run command failure: src/lib/dnssd/minimal_mdns/Server.cpp:344: CHIP Error 0x00000046: No endpoint was available to send the message

step:

1. close all wifi connections.
2. enter chip-tool's interactive mode.
3. run onoff toggle 0x12344321 1.
4. error is "No endpoint was available to send the message, this is in expections.
5. let wifi connect to AP.
6. run onoff toggle 0x12344321 1 again
7. error is "No endpoint was available to send the message. I think this is not in expections.

in some cases, for example, mdns initialization completes before wifi connection, it unable to return to normal status.

[bzbarsky-apple]

@nykh2010 Are you on Linux or Mac? It sounds like the platform is not dispatching relevant "network changed" notifications...

[bzbarsky-apple]

I am guessing Linux, since minimal mdns is involved.

[nykh2010]

@bzbarsky-apple yes, platform is Linux.

[andy31415]

Expectation for platform implementations is that minmdns would be restarted on networking changes.

Since notifications of networking changes is platform-specific, this probably has to be handled by the app on a platform by platform basis. I had a PR open for using a single listening socket which would have probably covered this as ANY would keep updating, however it ended up not playing well with LWIP (#27219).

I am unlikely to have time to add platform-specific dnssd restart logic to chip-tool or example apps for minmdns, however I would be happy to review patches for this.