Re: [lwip-users] PPP driver from lwIP

[narke]

Hi, Yoav

Thanks for you so quick reply.  See my inline replies also.


On 5 May 2011 21:30, Yoav Nissim <address@hidden> wrote:
>
>
> Hi Narke,
>
> See my inlined replies.
>
>
> On 5/5/2011 15:12, narke wrote:
>
>> Hi Yoav,
>>
>> Thanks for the answer,  I put some comment inside your replies.
>> Please have a look at them.
>>
>>
>> On 5 May 2011 19:33, Yoav Nissim <address@hidden> wrote:
>>>
>>> I have used lwIP's PPP but am not sure what you mean by "PPP driver from
>>> lwIP".
>> I will be using PPP over serial, and the serial line is connected to a
>> GPRS modem.  I am in a NO_SYS environment, i.e., embedded system
>> without OS.
> If your embedded system is not covered in the contrib module, you will
> have to implement the serial IO interfaces (sio_open, sio_close,
> sio_write, sio_read, etc..)

Yes, I see.

>>> Do you need to use PPP-over-serial or PPP-over-Ethernet?
>>>
>>>
>>> I used PPPoS for which I had to:
>>>
>>> 1. implement the serial IO interface defined in sio.h (see reference
>>> implementations in contrib module)
>>>
>>> 2. use the PPP APIs defined in ppp.h to establish, manage, and terminate
>>> a PPP link.
>> Beside the PPP APIs, do you actually use the implementaion (.c files
>> in netif/ppp directory)?
> I think I see what you meant by "lwIP PPP driver" - the location of the
> ppp directory is somewhat confusing.
> As opposed to the other files under the netif directory, the files under
> netif/ppp are not a sample or a skeleton.

Yes! You got my meaning exactly!  Now I am clear by your explanation.

> They _are_ the PPP client and API implementation (based on pppd code).
> This means they all have to be compiled into lwIP for you to be able to
> use PPP and its APIs (unless of course you decide to implement/import
> your own PPP engine - which I recommend against...).

Actually, our company was using lwIP 1.1.1 long time ago. Now I am
about to upgrade it to lwIP 1.3.2.  The confused thing is that the
current code fully skipped the PPP code provided with lwIP and made an
own PPP implementation, and the implementation is just a big ppp.c
file and looks absolutely different with the code in lwIP.  So I was
worrying about that the PPP module comes with lwIP is not really
usable.  Now, by your explanation, I have confidence to use the lwIP's
native PPP code.

>>>
>>> Take into consideration that:
>>>
>>> 1. as of lwIP 1.4.0 rc1, the APIs in ppp.h are not protected, i.e they
>>> should be called from the tcpip thread context.
>> I think this only matters for NO_SYS == false case. right?
> I believe so, although I cannot be absolutely certain.
>>> 2. IMO, not all the APIs in ppp.h are actually public....
>> What does this mean?
> I mean that I am not sure that all the functions defined in ppp.h should
> actually be called by someone looking to use PPP.
> I only use pppInit, pppOverSerialOpen, pppHup, pppClose and possibly a
> couple of others.

Got it.  Many thanks!


>>>
>>> HTH,
>>>
>>> Yoav.
>>>
>>>
>>>
>>> On 5/5/2011 13:18, narke wrote:
>>>
>>>> Hi,
>>>>
>>>> Does anyone have experience in using the PPP driver from lwIP?  Is
>>>> there even any example?  Thanks.
>>>>
>>>
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>>>
>>
>>
>
>
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narke
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