diff options
author | Harald Welte <laforge@gnumonks.org> | 2010-12-23 23:34:43 +0100 |
---|---|---|
committer | Harald Welte <laforge@gnumonks.org> | 2010-12-23 23:38:02 +0100 |
commit | f6bd340df6bcac716da78da8e35f379a7b853027 (patch) | |
tree | 13818dba492f0d54c6b217f498348d250f48cf0d /openbsc | |
parent | 985263e55f3b78cf3c67b2dc39edab4c6bf62ad4 (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')
-rw-r--r-- | openbsc/src/gprs/gprs_gmm.c | 1 | ||||
-rw-r--r-- | openbsc/src/gprs/gprs_sgsn.c | 19 |
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; |