[lwip-users] Re: [lwip] Why ack packets are not sent when snd_wnd is zero?

[Kieran Mansley]

On Tue, 5 Mar 2002, Mumtaz Ahmad wrote:
> I think it might result in memory leak in some scenarios like
>         if we send a delayed ack but the snd_wnd is zero . We have already
> allocated a seg and pbuf for it but could not empty pcb->unsent . If the
> receiver window remains zero for long time then on next timer expiry we
> would generate another delayed ack packet which would  overwrite the
> pcb->unsent .Now there is no information stored about the old ACK segement
> and it might be a memory leak.

I don't think there will be a memory leak.  pcb->unsent is a list of
unsent items, not just a single one.  When the second delayed ack was
generated and couldn't be sent it would be added to this list rather than
overwriting the list.  If you have a reference to the source file/line
where you think the memory leak is occuring I'd be happy to check it and
see if this really is the case.  I've searched for all the places where
pcb->unsent is updated and at first glance they seem ok.

Cheers,

Kieran

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