Hmm I thought this is the flow of the output :
netif->output(ethernetif_output) --> etharp_output (resolve
ARP)-->netif->lowleveloutput
I know that low level output is meant for for the actual transmission but my q
really is..
is the the first pbuf in the chain's payload pointer points to the headers...or
the actual data
without the headers..cause I read adam dunkel's notes and there he mentioned
that the
payload points the to the actual data.. skipping the headers. Can someone help
me clarify that ?
Thanks for the answer with the sockets api.. help me out a lot !
Ikhwan
> Date: Tue, 13 Nov 2007 18:47:17 +0000> From: [EMAIL PROTECTED]> To:
> [email protected]> Subject: Re: [lwip-users] Mapping pbuf to Buffer
> Descriptor on MPC582T> > Muhamad Ikhwan Ismail wrote:> > > > Hi guys,> > > >
> I am porting lwip1.2.0(not using CVS for updates) to MPC852t with a> >
> commercial RTOS from MQX I am a beginner in lwip. Got 2 qs on a problem> > I
> am having.> > > > 1. MPC852T has a dual port ram with buffer descriptors,
> which have> > pointers to the buffer/frame to be sent and the Ethernet
> controller> > automatically fetch the pointed data for transmission as soon
> as I set a> > flag up. The problem lies on the fact that the first-in-chain
> pbuf> > payload pointer points to the actual data and skipped the headers, or
> at> > least that is the way I understood it from the manual.> > No, the netif
> output function should be being called with the payload> pointing to the
> headers, as you would hope and expect.> > But perhaps the problem is that you
> have set the netif->output function to> be your driver, rather than
> etharp_output. You should find the> src/netif/ethernetif.c template driver
> gives you an idea of what's> involved, including in its init function:> >
> netif->output = etharp_output;> netif->linkoutput = low_level_output;> >
> Where low_level_output is that driver's call to transmit a packet.> > > 2.
> Can someone show me how do I initialise the lwip stack to be used> > with the
> sockets API (maybe the flow)?> > This has been tidied up and changed quite a
> bit in CVS, but even for 1.2.0> you should find an example of the functions
> to call to initialise the stack> in the ports directory hierarchy.> > > And
> is the usage of the sockets> > api allows the lwip to be multithreading able
> ?> > The code in CVS is a bit safer for multithreading. But in whichever
> code> base, it's important to remember that with lwIP you cannot use the
> same> socket (or netconn) from multiple threads. You can have different
> sockets> used by different threads though.> > Jifl> -- > eCosCentric Limited
> http://www.eCosCentric.com/ The eCos experts> Barnwell House, Barnwell Drive,
> Cambridge, UK. Tel: +44 1223 245571> Registered in England and Wales: Reg No
> 4422071.> ------["Si fractum non sit, noli id reficere"]------
> Opinions==mine> > > _______________________________________________>
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