can esp8266 sdk add keepalive get status interface?

[grantgao]

i enabled the keepalive in my tcp socket,and it can send and receive keepalive packt will local server ,but i power off my local server suddenly to test what can the esp8266 note me in this case,and result is nothing ! so i am thinking ,why keepalive do nothing in this case? LWIP stack sure know what happened at this time ,can you add a callback interface into sdk for us ?

[ESP_Faye]

Hi，

call espconn_regist_reconcb to register a reconnect callback, when TCP connection broke and retry fail, it goes into the reconnect callback.

Thanks for your interest in ESP8266 .

[grantgao]

Hi，

call espconn_regist_reconcb to register a reconnect callback, when TCP connection broke and retry fail, it goes into the reconnect callback.

Thanks for your interest in ESP8266 .

i know what you said,and i also implemented the callback like this "espconn_regist_reconcb(user_contype.pCon, we_link_reconn_cb);"
it sure can reconnect when TCP connection broken. but i mean the otherwise,you can test as follow step:
1.boot esp8266 and wait it connect with local TCP server successful
2.plug out Ethernet wire(RJ45 on you PC)
now ,you can see esp8266 report nothing and won't enter "espconn_regist_reconcb" also

[grantgao]

E文不好，还是用中文描述一遍吧，就是ESP8266------路由器------本地PC（TCP SERVER），其中路由器和PC是网线连接的，8266作为TCP client连上tcp server以后，如果此时拔掉PC端的网线，8266并无任何反应。如果有keepalive的话，底层的协议栈肯定知道这时候keepalive是收不到回应包的，从而可以通知用户程序，所以我才想到能否在sdk增加这样一个callback接口。

[ESP_Faye]

您好，

麻烦调用 espconn_set_opt 设置 enable TCP keepalive

调用 espconn_regist_reconcb 注册 reconnect callback

当连接断开后，等待几分钟，底层 retry 失败后会进入 reconnect callback