Re: [lwip-devel] Re: [task #7040] Work on tcp_enqueue

[Kieran Mansley]

On Sun, 2009-02-01 at 13:25 +0100, Jakob Stoklund Olesen wrote:
> Here is a plan:
> 
> 1. Split tcp_enqueue in two: data+options.
> 
> 2. Move checksumming from tcp_output_segment to tcp_enqueue. Some header
>    fields are updated in tcp_output_segment. Update the checksum.
> 
> 3. Use inet_chksum_memcpy to checksum on the fly. Incrementally update
>    seg->tcphdr->chksum when adding data.
> 
> 4. Allocate larger pbufs using clever strategy. pcb->unsent_tail_space
>    holds the number of extra bytes available in the final pbuf of
>    pcb->unsent.

Lets do these separately and one at a time.  I'm quite conservative
about changes in the core stack, particularly if they're changing the
API.  The move to split tcp_enqueue into two sounds OK as long as we
don't end up with much bigger code, and I'm happy to see a neat change
to avoid half-filled pbufs.  I'm not sure what all the checksumming
changes will give us though.

Kieran