Re: [lwip-devel] lwIP + SLIP/PPP single threaded

[Simon Kallweit]

address@hidden schrieb:
> Simon Kallweit wrote:
> > SLIP needs to be changed, so that slipif_input() assumes non-blocking 
> > reads on the serial io and returns when no more data can be read. 
> > This can be done rather easily.
> Exactly. After all, for lwIP, SLIP is only another netif and the 
> current implementation happens to be blocking...

So it's fine if this is changed to non-blocking? This would need me to 
move the local variables of the slipif_input() function to some private 
struct attached to the netif. What's the best solution for that? Is it 
fine to allocate some memory during slipif_init call and use 
netif->state as a pointer to the struct? Or is there some other 
preferred way?

> > PPP would need to be changed in a similar fashion, making it 
> > non-blocking, and in addition provide a separate timeout implementation.
> I wouldn't know exactly since I didn't yet _use_ lwIP PPP (only 
> browsed through the source code deciding not to try it :), but isn't 
> the existing timeout management of lwIP enough for PPP, too?

The timeout management of lwIP is fine, but if I'm going to use 
NO_SYS=1, the timeout system is just empty macros. And that's exactly 
what I'm aming for.

> > I was wondering what version of pppd was used for the current lwIP 
> > ppp implementation?
> I'm afraid I don't understand that question? Is pppd (I assume you 
> mean the *nix one) mentioned there somewhere? I'd guess it could be 
> used against any version of pppd as long as you run that with the 
> correct settings (which can get quite complicated).

It was just my rough guess that the PPP netif is adapted from the Unix 
pppd package. A diff at least shows some similarity, so I was wondering 
if it would be worth updating to the current pppd implementation. 
Unfortunately this looks like quite a bit of work ...

> > Is it currently maintained?
> >   
> You mean lwIP PPP, right? The sad answer is: no. Since none of the 
> (4?) active developers seems to be using it, the only active 
> development currently is coming from 'users' on lwip-devel or 
> lwip-users sending in patches.

Ok, that's what I was afraid of :)

> > Is anyone interested in helping out?
> >   
> I guess we'd all be happy to see someone working on lwIP PPP: any 
> users wanting to become active developers + maintainers for this part 
> are of course welcome!

I really need PPP for our product. But it's all a matter of time ...

Simon