Re: [lwip-users] ppp-new IP forwarding only works one direction (Ethernet to PPP)

[Simon Goldschmidt]

Sylvain Rochet wrote:
> Oh dear, now I see what is happening.
> 
> PPP header is smaller than Ethernet header
> [..]
> This is actually a lwIP design issue, the only way we can fix that is by
> adding a configuration option so pbuf from PPP are allocated with enough
> extra space so a Ethernet header will fit in place of a PPP header.

The lwIP way to solve this is to defin PBUF_LINK_HLEN to be big enough for both 
sides.
We do waste some bytes that way, but it should work.

However, I just saw that PPP (new?) seems to allocate many pbufs as PBUF_RAW, 
which
kind of breaks the link-header size calculation and thus might make my 
suggestion
not work...

Anyway, we might want to fix this in a generic way...

Simon