Re: [lwip-devel] New buffer management code (fwd)

[lukem . lwip]

On Wed, 3 Dec 2003, Kieran Mansley wrote:
> > The motivation has been to have the ability to add special pbuf types
> > dynamically to allow for things like handling memory which is allocated
> > externally to the system, and requires extra information to be attached to
> > the pbuf.
>
> Could you explain this in more detail?  I thought that the PBUF_REF type
> would cover the case of memory not allocated by lwIP.

Ok. The reason our particular project needs this feature is that we need
to keep trak of extra information which is associated with that buffer -
we need to know who allocated the data so that we can callback the
appropriate service (for example a device driver) so that it can free the
buffer.

Aditionally, we are using lwIP on a capability based system, so that we
need to keep track of the password associated with the buffer as well.

I can imagine lots of other cases where someone using lwIP might need to
perform extra work on allocation and free too, so providing generic
support for it is a nicer solution than putting special case code
everywhere.

--
Luke Macpherson