Re: [lwip-users] lwip does not ack retransmissions

[john bougs]

> 
> So perhaps you could submit a task at
> http://savannah.nongnu.org/projects/lwip to sort this out
> so it doesn't get
> forgotten. But thinking about it, it shouldn't be that
> difficult really...
> in fact I speculate it would just involve adding something
> like the
> following in pbuf.c:
> 
> #if TCP_QUEUE_OOSEQ
> #include "lwip/tcp.h"
> #endif
> 
> #if TCP_QUEUE_OOSEQ
> #define ALLOC_PBUF(p) do { (p) = alloc_pbuf_pool(); } while
> (0)
> #else
> #define ALLOC_PBUF(p) do { (p) =
> memp_malloc(MEMP_PBUF_POOL); } while (0)
> #endif
> 
> #if TCP_QUEUE_OOSEQ
> /* Attempt to reclaim some memory from queued
> out-of-sequence packets */
> /* It's better to give priority to new packets if
> we're running out. */
> static struct pbuf *
> alloc_pbuf_pool(void)
> {
>   struct tcp_pcb *pcb;
>   struct pbuf *p;
> 
> retry:
>   p = memp_malloc(MEMP_PBUF_POOL);
>   if (NULL == p)
>   {
>     for (pcb=tcp_active_pcbs; NULL != pcb; pcb =
> pcb->next) {
>       if (NULL != pcb->ooseq) {
>         tcp_segs_free(pcb->ooseq);
>         pcb->ooseq = NULL;
>         goto retry;
>       }
>     }
>   }
>   return p;
> }
> #endif /* TCP_QUEUE_OOSEQ */
> 
> Then change the two calls to memp_malloc(MEMP_PBUF_POOL) in
> pbuf_alloc() to
>  ALLOC_PBUF_POOL(p).
> 
> If you don't mind giving this a spin, that would be
> great. I'm not in a
> position to test it (I've just written it off the top
> of my head).
> 
Had to change the macro name to ALLOC_PBUF_POOL, and the second call to use 
(q).... but it worked.   From an efficiency view point this works a little 
better, but not much.  Sometimes the TCP_QUEUE_OOSEQ = 0 creates a bunch of 
traffic, but they both take about the same time to resolve the issue 
...200-400ms.     

I understand what happening now so am much happier.  I will submit the request 
tomorrow.  Thank you for your help.