Hi, it wasn´t handly written diffs but here I send diff made by using git diff. And the problem you can see in packets with number 27-40 (especially see in number 30 you see there the old tlli and newly generated P-TMSI in message attach accept and in number 31 there is new TLLI which is the same as generated P-TMSI in previous message) and that is the problem I needed to solve, that the new TLLI was not LOCAL.

regards Michal

2014-05-23 13:16 GMT+02:00 Holger Hans Peter Freyther <holger@freyther.de>:

On Fri, May 23, 2014 at 11:44:40AM +0200, Michal Grznár wrote:

Hi,

> And the problem was as I said in Imsi attach procedure new TLLI == new
> allocated P-tmsi, and there was a problem that the function  gprs_tmsi2tlli()
> function there was not called and so I had to mask the upper bits in
> function where the p-tmsi is allocated, there is also a pcap trace where
> you can see it.

Could you please elaborate of what/were (e.g. packet numbers) we
can see "it" and what it should be instead? And please use "git diff"
or preferable "git commit" and git format-patch. The "diff" you include
is hand-written and sadly not usable because of this.

And as written by Harald before. The place you patch is not correct.
The method you patch should generate a unique P-TMSI. It might should
mask some of the higher bits. But you need to look at the callers of
this function if the tlli is not updated.

e.g. in src/gprs/gprs_gmm.c you will see something like this:

        ctx->p_tmsi = sgsn_alloc_ptmsi();
#endif

        /* Even if there is no P-TMSI allocated, the MS will switch from
         * foreign TLLI to local TLLI */
        ctx->tlli_new = gprs_tmsi2tlli(ctx->p_tmsi, TLLI_LOCAL);

        /* Inform LLC layer about new TLLI but keep old active */
        gprs_llgmm_assign(ctx->llme, ctx->tlli, ctx->tlli_new,
                          GPRS_ALGO_GEA0, NULL);

So this call to gprs_tmsi2tlli will make sure that 0xc0000000 will
be set. In fact I see two calls to sgsn_alloc_ptmsi and both of them
do the above and assign the new tlli to the context. So please could
you try to explain what you are trying to solve?

holger