Re: [lwip-users] Question about socket send

[Kieran Mansley]

On Mon, 2009-07-20 at 10:53 +0100, Kieran Mansley wrote:
>  This won't be fixed before 1.3.1 as I think it needs more
> thought.  I'm sure it's something that has been discussed before but I
> don't remember the conclusion.

The closest we got looks to be this patch:

http://lists.nongnu.org/archive/html/lwip-users/2007-12/msg00103.html

(the patch includes lots of other stuff too, it's the pbuf_split() and
tcp_split_unsent_seg() bits that are relevant).

RFC 793 says:

     "Another suggestion is for the sender to avoid sending small
      segments by waiting until the window is large enough before
      sending data.  If the the user signals a push function then the
      data must be sent even if it is a small segment."

So, while we're doing what it suggests in lwIP, we may need to split the
packet and send anyway if the PSH bit is set.  It would be interesting
to know if that is the case here.

I think this warrants a bug on savannah, as it needs to be fixed to
avoid deadlock.

Kieran