[lwip-devel] Status of lwip keepalive flag

[Bjørn Liene Gundersen]

Hi,

 

I am using lwIP version 1.3.2 together with the lwIP port for Atmel AVR32 microcontrollers. The OS is FreeRTOS v. 6.0.0. Programming environment is AVR32 Studio 2.6.0.

 

I have a server program and I have enabled keepalive in lwIP, and I can see that it is working using wireshark. However in my current network thread, I am accepting the connection and then closing it for each new command/answer from/to the client. I want to let the connection be active as long as the client not shut down, or the network cable is not unplugged or some other network failure. I see that the keepalive messages is going when the connection is up, and close the connection when a network error occurs. But... how can I know when the connection is closed by keepalive, for instance if the network cable suddenly is unplugged? I need to know this in order to know when I shall start a lwip_accept again! Is there a system call in lwIP that can tell me based on TCP keepalive if the connection is down or not? If not, I suggest this as an enhancement to the lwIP.

 

So, how can I know the status of lwIP keepalive flag?

 

Best regards

 

Bjørn Liene Gundersen

R&D Engineer

 

Tronrud Engineering AS

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