Re: [lwip-devel] Adding a static route table in LwIP

[Russ Dill]

On Fri, May 22, 2015 at 9:52 AM, Daniel Gutson
<address@hidden> wrote:
> On Thu, May 21, 2015 at 12:59 PM, Ivan Delamer <address@hidden> wrote:
>> Hi Pradip,
>>
>> I think a static IPv6 route table is a nice feature to have. I think some
>> people have implemented something similar for IPv4. Also someone has
>> implemented a NAT.
>
> Hi all.
>
> Sorry if my question/suggestion is completely out of place. Please
> note that I'm not a telecommunications expert,
> but a user (of real time and embedded systems which use LwIP).
>
> Would adding this as a plug-in be a good idea?
> Or more specifically: would an extension mechanism where features like
> this one could be added
> aside of the core library? Of course I don't mean dynamic loading, but
> just to provide a set of hooks
> placed in the right places so extensions could register callbacks.
>
> Could that make sense? The first step would be to add the appropriate
> hooks (then refactor this feature
> and possible other features such as NAT as well, so they can be
> written as opt-in extensions?).
> The main purpose would be neat maintainability.
>
> Please let me know. If this happens to make sense, we could see how to
> collaborate.


Both solutions are possible, but keep in mind that lwIP is "a
light-weight implementation of the TCP/IP protocol suite", and "The
focus of the lwIP TCP/IP implementation is to reduce the RAM usage".
So any patch to lwIP has to take into account bloat. Adding a feature
that can be compiled in or out does not effect the size of lwIP for
users that do not enable that feature. Adding hooks that can call into
external or compiled in modules increases the code size even for users
that don't enable that extra module.