sgsn: Re-add searching for MM ctx based on TLLI / P-TMSI matches

If an MM context cannot be found based on BBSGP info and a RA UPDATE
REQUEST is received, try to find an MM context with an P-TMSI from
which the TLLI could have been derived. This also checks, whether the
routing area matches.

This is similar to the old behaviour removed by the commits
"sgsn: Only look at TLLIs in sgsn_mm_ctx_by_tlli" and
"sgsn: Remove tlli_foreign2local", except that this will only
be done for RA UPDATE REQUESTs now.

Sponsored-by: On-Waves ehf

1 files changed, 4 insertions, 0 deletions

diff --git a/openbsc/include/openbsc/gprs_sgsn.h b/openbsc/include/openbsc/gprs_sgsn.h
index 61120b1e3..74f073597 100644
--- a/openbsc/include/openbsc/gprs_sgsn.h
+++ b/openbsc/include/openbsc/gprs_sgsn.h
@@ -178,6 +178,10 @@ struct sgsn_mm_ctx *sgsn_mm_ctx_by_tlli(uint32_t tlli,
 struct sgsn_mm_ctx *sgsn_mm_ctx_by_ptmsi(uint32_t tmsi);
 struct sgsn_mm_ctx *sgsn_mm_ctx_by_imsi(const char *imsi);
 
+/* look-up by matching TLLI and P-TMSI (think twice before using this) */
+struct sgsn_mm_ctx *sgsn_mm_ctx_by_tlli_and_ptmsi(uint32_t tlli,
+					const struct gprs_ra_id *raid);
+
 /* Allocate a new SGSN MM context */
 struct sgsn_mm_ctx *sgsn_mm_ctx_alloc(uint32_t tlli,
 					const struct gprs_ra_id *raid);