RE: [lwip-devel] [bug #25629] keep-alive not working.

[Stephane Lesage]

>  tcphdr->ackno = htonl(pcb->rcv_nxt);
>  TCPH_FLAGS_SET(tcphdr, 0);
>  tcphdr->wnd = htons(pcb->rcv_ann_wnd);
>  tcphdr->urgp = 0;
> 
> with:
> 
>  tcphdr->ackno = htonl(pcb->rcv_nxt);
>  TCPH_FLAGS_SET(tcphdr, TCP_ACK);
>  tcphdr->wnd = htons(pcb->rcv_ann_wnd + 1);  tcphdr->urgp = 0;
> 
> (I've also fixed the window in the packet with that change to 
> not shrink what we advertise by one octet).
> 
> If that works, please open a bug and this code should get 
> checked in. We should really make the same change to the 
> tcp_zero_window_probe() function below it which has the same 
> block of code.

Hi,

I updated my LwIP with the CVS head yesterday,
and I enabled the TCP Keep-Alive on several TCP connections on my device.

I had the exact same problem, and the suggested patch did the work pretty well.

I think somebody should check it in.

Regards.

-- 
Stéphane LESAGE
ATEIS International