Hi Dieter,

...

- In gprs_bssgp.c  the function bssgp_rx_ul_ud calls :

bts = gsm48_bts_by_ra_id(                                  TLVP_VAL(&tp, BSSGP_IE_CELL_ID),                                  TLVP_LEN(&tp, BSSGP_IE_CELL_ID));

But gsm48_bts_by_ra_id defined in gsm_04_08_gprs.c takes 3 arguments the gsm_network as first one then the buffer and lenght. Since the function was implicitely defined in gprs_bssgp.c, it compiled but of course segfaulted as soon as it got there ... I don't even understand how it worked for you.

At the time I made the trace, I did not yet have connected with a GPRS phone. In the meantime I made a temporary workaround by referencing the global "bsc_gsmnet" and using it for the first parameter.

Yes, I did the same because I couldn't find any way to get a proper gsm_network at that point in the code ...

...

<0004> gsm_04_08_gprs.c:434 GMM RA UPDATE REQUEST type="RA updating"  REJECT <0004> gsm_04_08_gprs.c:408 <- ROUTING AREA UPDATE REJECT

But as soon as the REJECT is sent to the BTS, it reboots ... no error no message nothing ...

I get a "GMM Attach Request" with my phone and the same behaviour afterwards, the nanoBTS reboots.

I found out the problem.

In gprs_bssgp_tx_dl_ud, then length encoded in the PDU TLV is incorect. It uses msg->len but at that point it already did a msgb_push to add space for the header so msg->len is already too big. You need to save the size of msg->len before the msgb_push and then use that when encoding the PDU TLV length.

Now, the MS tries to do :

<0004> gsm_04_08_gprs.c:434 GMM RA UPDATE REQUEST type="RA updating" REJECT <0004> gsm_04_08_gprs.c:408 <- ROUTING AREA UPDATE REJECT

repeatedly ... (3 or 4 times before giving up)

BTW, do you sometimes hangout in #openbsc ?

Sylvain