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authorHarald Welte <laforge@gnumonks.org>2010-12-23 23:34:43 +0100
committerHarald Welte <laforge@gnumonks.org>2010-12-23 23:38:02 +0100
commitf6bd340df6bcac716da78da8e35f379a7b853027 (patch)
tree13818dba492f0d54c6b217f498348d250f48cf0d /openbsc/src
parent985263e55f3b78cf3c67b2dc39edab4c6bf62ad4 (diff)
GPRS/GMM: Correctly look up MM Context in RA Update
If a MS changes RA, the RA will arrive in the new cell using the old TLLI (masked as foreign TLLI). So we need to look-up the TLLI in a special way, using the old RA as indicated in the 04.08 GMM message. There is still another bug remaining: As we somehow create a new LLC, the sequence numbers of our responses start from 0 again, which is not what the MS expects. This needs to be fixed in a follow-up patch.
Diffstat (limited to 'openbsc/src')
-rw-r--r--openbsc/src/gprs/gprs_gmm.c1
-rw-r--r--openbsc/src/gprs/gprs_sgsn.c19
2 files changed, 19 insertions, 1 deletions
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index 817092e31..82a4ca85b 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -899,6 +899,7 @@ static int gsm48_rx_gmm_ra_upd_req(struct sgsn_mm_ctx *mmctx, struct msgb *msg,
}
/* Look-up the MM context based on old RA-ID and TLLI */
+ mmctx = sgsn_mm_ctx_by_tlli(msgb_tlli(msg), &old_ra_id);
if (!mmctx || mmctx->mm_state == GMM_DEREGISTERED) {
/* The MS has to perform GPRS attach */
DEBUGPC(DMM, " REJECT\n");
diff --git a/openbsc/src/gprs/gprs_sgsn.c b/openbsc/src/gprs/gprs_sgsn.c
index ae18ea0fa..48a00b822 100644
--- a/openbsc/src/gprs/gprs_sgsn.c
+++ b/openbsc/src/gprs/gprs_sgsn.c
@@ -82,6 +82,12 @@ static int ra_id_equals(const struct gprs_ra_id *id1,
id1->lac == id2->lac && id1->rac == id2->rac);
}
+/* See 03.02 Chapter 2.6 */
+static inline uint32_t tlli_foreign(uint32_t tlli)
+{
+ return ((tlli | 0x80000000) & ~0x40000000);
+}
+
/* look-up a SGSN MM context based on TLLI + RAI */
struct sgsn_mm_ctx *sgsn_mm_ctx_by_tlli(uint32_t tlli,
const struct gprs_ra_id *raid)
@@ -96,7 +102,8 @@ struct sgsn_mm_ctx *sgsn_mm_ctx_by_tlli(uint32_t tlli,
}
tlli_type = gprs_tlli_type(tlli);
- if (tlli_type == TLLI_LOCAL) {
+ switch (tlli_type) {
+ case TLLI_LOCAL:
llist_for_each_entry(ctx, &sgsn_mm_ctxts, list) {
if ((ctx->p_tmsi | 0xC0000000) == tlli ||
(ctx->p_tmsi_old && (ctx->p_tmsi_old | 0xC0000000) == tlli)) {
@@ -104,6 +111,16 @@ struct sgsn_mm_ctx *sgsn_mm_ctx_by_tlli(uint32_t tlli,
return ctx;
}
}
+ break;
+ case TLLI_FOREIGN:
+ llist_for_each_entry(ctx, &sgsn_mm_ctxts, list) {
+ if (tlli == tlli_foreign(ctx->tlli) &&
+ ra_id_equals(raid, &ctx->ra))
+ return ctx;
+ }
+ break;
+ default:
+ break;
}
return NULL;