The IDF websocket server does not handle multiple simultaneous connections (at least the example doesn't) (IDFGH-7162)

[pjsg]

Environment

• Development Kit: Random ESP32 board
• Module or chip used: ESP32-DOWDQ6
• IDF version (run git describe --tags to find it):
  v4.4-beta1-284-gd83021a6e8
• Build System: idf.py
• Compiler version (run xtensa-esp32-elf-gcc --version to find it):
  xtensa-esp32-elf-gcc (crosstool-NG esp-2021r2) 8.4.0
• Operating System: Linux
• (Windows only) environment type: [MSYS2 mingw32|ESP Command Prompt|Plain Command Prompt|PowerShell].
• Using an IDE?: No
• Power Supply: USB

Problem Description

I'm running the IDF4.4 (commit d83021a) and running the unmodified example examples/protocols/http_server/ws_echo_server.

To test it, I'm using websocat (from https://github.com/vi/websocat ) to make a connection to the websocket server and interact with it. In particular, I have this script (called dosend -- and this particular board is at 192.168.1.131)

#!/bin/bash

(echo foo; sleep 1; echo bardsfsdkfsdflskf; sleep 1; echo djfsldkjfskljfslkjfsdlkjfsldkjfklsjfslkf) | websocat ws://192.168.1.131/ws 

This script works fine provided that I only run one copy at a time. If I run four copies at the same time, then I get log messages from the ESP32 like:

W (34089) httpd_ws: httpd_ws_recv_frame: WS frame is not properly masked.
E (34089) ws_echo_server: httpd_ws_recv_frame failed to get frame len with 259

I launch four copies with the command (on my linux laptop)

./dosend & ./dosend & ./dosend & ./dosend &

I originally found this in an application that I was building, but the issue reproduces in the provided echo example.

Other items if possible

Since this is just your sample code, I'm not providing any other information here

[pjsg]

I did post a message on the forum, but that has no traction: https://esp32.com/viewtopic.php?f=13&t=26663&sid=b9ec90deb3701f18c7e782242527c4a2#

[Alvin1Zhang]

Thanks for reporting.

[chegewara]

Thats correct, this example is not ready to handle multiple connections.
WS is using fd for every connected client and you have to keep tracking every fd since connection till disconnection and publish messages using active fd.

• fd - file descriptor

[pjsg]

Just to be clear, are you saying that the example is broken and that the IDF core code is correct?

[chegewara]

As far as i know it works perfectly fine. Of course i may be wrong.

My suggestion is to add log after this line to see value of resp_arg->fd:
https://github.com/espressif/esp-idf/blob/master/examples/protocols/http_server/ws_echo_server/main/ws_echo_server.c#L59

[ESP-YJM]

@pjsg Could you please try this patch. I test it with your tool and it is ok.
ws_server.zip

[pjsg]

Thanks for this. I'll try and test it over the next couple of days.

[pjsg]

I'm sorry that it took me so long -- but that patch works great and fixes my problem (the Lua nodemcu firmware).

When will it get merged?

[Alvin1Zhang]

Thanks for sharing the updates, we have a fix under internal reviewing, and the issue will close automatically once the fix is available on GitHub, thanks.

[Alvin1Zhang]

Thanks for reporting and sorry for slow turnaround, fix is available at b3ab2c6 and fix on release/4.4 is available d72ba54. Feel free to reopen.

[AnkDhage]

Even I am trying to handle diff channels thru idf ws server, it does not work

[ESP-YJM]

@AnkDhage Do your problem is the same as the issue mentioned? Could you give a detailed description about it?