Links2004
commented
5 years ago the reconnect interval setting is not implemented for async right now.
Open leventesen opened 5 years ago
Links2004
commented
5 years ago the reconnect interval setting is not implemented for async right now.
nouser2013
commented
5 years ago Hmmm, observing the same thing for synchronous version. According to your code, this shouldn't happen.
But, when the server OS correctly reports an RST after ESP32 SYN's, I see immediate SYN flooding in wireshark. It does not matter if the WS server is not running in the first place or is terminated after WS connection was established.
I set the reconnect interval to 5000 after begin().
In my understanding, each call of .loop() will try to open a TCP connection, regardless of elapsed time since last failed attempt. Is there a way to debug this?
EDIT#1: After adding an appropriate Serial.print() to WebSocketsClient.cpp#136, I observe that _lastConnectionFail is always 0, _reconnectInterval is correctly set to 5000.
EDIT#2: got it _client.tcp->connect(_host.c_str(), _port) apparently returns non-zero, even if connection was rejected via server RST. As this seems to go deep down into the tcp code basement, I don't know how to continue from here.
Links2004
commented
5 years ago ok looks like a ESP32 TCP stack problem then.
you can try to check the result of the lwip_connect_r call here:
https://github.com/espressif/arduino-esp32/blob/master/libraries/WiFi/src/WiFiClient.cpp#L229
for some reason the return value there is not checked which makes no sense to me right now.
if(lwip_connect_r(sockfd, (struct sockaddr*)&serveraddr, sizeof(serveraddr)) != 0) {
log_e("lwip_connect_r: %d",errno);
close(sockfd);
return 0;
}
int res = select(sockfd + 1, nullptr, &fdset, nullptr, timeout<0 ? nullptr : &tv);
if (res != 1)
{
log_e("select: %d",errno);
close(sockfd);
return 0;
}for reverence:
https://github.com/espressif/esp-lwip/blob/e6f0cab39b3831bd56e83615fd65851294ca6ed4/src/api/sockets.c#L3447 https://github.com/espressif/esp-lwip/blob/e6f0cab39b3831bd56e83615fd65851294ca6ed4/src/api/sockets.c#L886
nouser2013
commented
5 years ago ok looks like a ESP32 TCP stack problem then. you can try to check the result of the lwip_connect_r call here: https://github.com/espressif/arduino-esp32/blob/master/libraries/WiFi/src/WiFiClient.cpp#L229
Hi, just tried your patch - this seems to work, partially. Even with ws.loop() called in each Arduino-Loop, there is now only one attempt every 5 seconds, behaviour as expected.
But now I don't seem to be able to open a regular connection. For some reason, now the ESP32 will RST the connection. Meaning with a running server on the PC on the correct port, this pattern repeats every 5 seconds:
So, my workaround is still a ticker setting a flag every 5 seconds. I can only process one message this way, but better than SYN flooding.
In async mode, Reconnect interval is set to 60000, WebSocketsClient is used, What I want is to terminate unauthorized connections in server side. When I terminate or close the connection then WebSocketsClient reconnects immediately like a loop or flood.