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

[LMao]

Sylvain,

Great, the latest patch works. Thank you very much.

Charles

-----Original Message-----
From: address@hidden [mailto:address@hidden On Behalf Of Sylvain Rochet
Sent: Friday, April 11, 2014 2:01 PM
To: Mailing list for lwIP users
Subject: Re: [lwip-users] ppp-new IP forwarding only works one direction 
(Ethernet to PPP)

Hello Charles,


On Fri, Apr 11, 2014 at 12:13:02PM +0000, address@hidden wrote:
> Sylvain,
> 
> I applied the new patch, but the following statement always cause Data 
> Abort exception run-time error. No matter I set ETH_PAD_SIZE to 0 or 
> 2. The good thing is my compiler doesn't generate any error message 
> for the new patch.
> 
> *((ppp_pcb**)payload) = pcb;

Yeah, of course, there is an alignment problem here, pbuf->payload might be 
unaligned, here is a new patch with an helper packed struct which should fix 
the issue.

It was fine with a PBUF_RAW because the pointer was put deliberately in front 
of the buffer, buffer which was allocated on alignment by lwIP.

You don't need to set ETH_PAD_SIZE, this is not necessary.


> Another thing I am not so sure is the macro PPP_USE_PBUF_RAM. I always 
> set it to 1 in lwipopts.h, but I think the default is set to 0 in 
> opt.h. Am I doing the right thing?

Yes!, if you have a heap PPP_USE_PBUF_RAM is the option you should use, it 
allows you to use a smaller PBUF_POOL_BUFSIZE.


Sylvain