RE : [lwip-users] LWIP, PPP and GPRS

[VANSTAEN Laurent RD-MAPS-GRE]

Hi,

   I've re-thought  about my code and I've seen that the inits for FSM are called lcp_init() and pppOpen(). That part seems OK now.

Now I dial my modem, call pppInit(), pppSetAuth() and pppOpen(), and then try to open a PDP context (AT command AT+CGDCONT). I get an error message CREG:2 (no network found). I know the AT commands, I have already tested my GPRS modem with kermit and pppconnect with Linux, and it doesn't seem to be a problem with AT commands. Somehting is still missing in my previous PPP calls. Does it sound familiar to you ?

 

Thanks,

 

Laurent Vanstaen

 

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Michael's answer :
A couple of things jump out at me:

I don't understand what you are doing with ppp->session and ppp->statemachine.

You forgot to call tcpip_init. This init is quite important to PPP.

You aren't supposed to call any of the FSM routines yourself. I'm not sure why you would want to.

It looks as if you've tried to open PPP before dialing up your GPRS modem? I don't think that will work.

One last thing, I think it would be better if you could keep the LWIP discussions on the mailing list. Thanks.

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My initial message to Michael :

Hi,
I've just read your posts on the LWIP forum and I've got a few questions if you have some time.
I'm trying to use lwip with PPP and a GPRS module I've written that takes care of AT commands. My init code looks like that :

initModem(); // This sends some AT commands to reboot the GPRS modem for example

// PPP Session initialization
ppp->session = (struct sessiondata*) CALL(ppp->allocator, alloc, sizeof(struct sessiondata));
ppp->state_machine = (fsm*) CALL(ppp->allocator, alloc, sizeof(fsm));
ppp->login = "******";
ppp->password = "*****";

stats_init();
mem_init();
memp_init();
pbuf_init();
pppInit();
fsm_init(ppp->state_machine); // FSM State = INITIAL after the init
fsm_lowerup(ppp->state_machine); // FSM State becomes CLOSED
fsm_open(ppp->state_machine); // FSM State becomes REQSENT
pppSetAuth(PPPAUTHTYPE_CHAP,ppp->login, ppp->password);

// Calls LWIP pppOpen() after some particuliar treatment
WrappedPPPopen(NULL, APN, ppp->session->proto, 0);

// Tests of the phone functionnalities
CALL(ppp->modem, phonecall, phoneNumber);

other tests ...


The initModem phase looks good, all the inits are OK, but my peer keeps sending Configure-Request packets without any answer from the other end (which should be my GPRS provider).

Do you have any idea where this could come from ?

Thank you,

Sincerely,

Laurent Vanstaen
France Telecom R&D