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jeelabs / esp-link

esp8266 wifi-serial bridge, outbound TCP, and arduino/AVR/LPC/NXP programmer
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Connection closed after 5 minutes idle #406

Open KjellVerb opened 5 years ago

KjellVerb commented 5 years ago

I want to keep the connection to my ESP open for as long as I want without having to close it or without having to send dummy packets. I've already changed (in serbridge.h) #define SER_BRIDGE_TIMEOUT 300 // 300 seconds = 5 minutes into #define SER_BRIDGE_TIMEOUT 36000 // 36000 seconds = 10 hours but to no avail... Any suggestions on where else I can find and change the timeout?

uzi18 commented 5 years ago

You mean connection on port 23? Are you sure esp—link breaks connection - not other side?

KjellVerb commented 5 years ago

Yes I do, sorry for not specifying I'm not 100% sure and not sure how to test, but I do think that it's the ESP breaking the connection. I use TeraTerm as a terminal program and in telnet mode it can send keepalives and the connection won't close automatically, but when using a raw connection it does not send keepalives and then the connection closes after 5min. The problem is that the telnet negotiation causes issues on the UART so I need to connect in raw mode.

tve commented 5 years ago

The Espressif SDK times out unused connections. I believe there's a function you can call to change that. Beware that the number of sockets is very limited and you may risk not being able to connect due to open inactive sockets that didn't close properly.

KjellVerb commented 5 years ago

How limited are we talking? What real-world examples would cause a socket to not close properly?

In my application the esp-link gets power-cycled quite often so it should not really be a problem. Even then, couldn't it be remotely solved by resetting the esp-link via the webpage or does that also count as opening a socket?

Do you have any suggestions on where to find more info about the function call that would allow me to change the timeout?

tve commented 5 years ago

I forgot that this is already done: https://github.com/jeelabs/esp-link/blob/fe4f565fe83f05e402cc8d8ca3ceefbc39692a1f/serial/serbridge.c#L608 Max is 7200 seconds. 0 might work for "forever". Maybe you can post something from the esp-link debug console that shows when the connections get cut? There may be a clue there...

KjellVerb commented 5 years ago

Thanks, from the SDK programming guide:

3. espconn_regist_time
Function:
Register timeout interval of ESP8266 TCP server.
Note:
Call this API after espconn_accept, before listened a TCP connection.
 This timeout interval is not very precise, only as reference.
If timeout is set to 0, timeout will be disable and ESP8266 TCP server will
not disconnect TCP clients has stopped communication. This usage of
timeout=0, is deprecated.

Prototype:
sint8 espconn_regist_time(
 struct espconn *espconn,
 uint32 interval,
 uint8 type_flag
)
Parameters:
struct espconn *espconn : corresponding connected control block structure
uint32 interval : timeout interval, unit: second, maximum: 7200 seconds
uint8 type_flag : 0, set all connections; 1, set a single connection 
Return:
0 : succeed
Non-0 : error code ESPCONN_ARG - illegal argument，can’t find TCP
connection according to structure espconn

I'll give it a go, probably my setting it to 36000 just failed and kept the default 300 sec?

KjellVerb commented 5 years ago

It works fine at 7200 seconds, this issue can be closed.

gdelconti commented 3 years ago

Hello, this is what I just did to change the timeout:

  1. get esp-link 3.2.47alpha make environment working as per #155
  2. change #define SER_BRIDGE_TIMEOUT 7200 in esp-link/serbridge.h
  3. start make in esp-link directory
  4. flash the generetad user1.bin

I don't see any changes in connection timeout that is stuck with the default 5 minutes value

What I am doing wrong?