From d58c033305a644b5c44a836ce8bc7a552499014d Mon Sep 17 00:00:00 2001
From: Jacob Erlbeck <jerlbeck@sysmocom.de>
Date: Mon, 4 Jan 2016 18:43:35 +0100
Subject: [PATCH] sgsn: Only look at TLLIs in sgsn_mm_ctx_by_tlli

Currently the code also matches the TLLI against LOCAL and FOREIGN
mappings of the P-TMSI, thus eventually finding MM contexts not
consistent with the TLLI (both tlli and tlli_new differ). On
the other hand, tlli_new is not checked at all.

This commit changes the function to only look at mmctx->tlli,
mmctx->tlli_new, and the routing area.

Sponsored-by: On-Waves ehf
---
 openbsc/src/gprs/gprs_sgsn.c   | 31 +------------------------------
 openbsc/tests/sgsn/sgsn_test.c |  2 +-
 2 files changed, 2 insertions(+), 31 deletions(-)

diff --git a/openbsc/src/gprs/gprs_sgsn.c b/openbsc/src/gprs/gprs_sgsn.c
index 8f8bdc68e..f71066d8e 100644
--- a/openbsc/src/gprs/gprs_sgsn.c
+++ b/openbsc/src/gprs/gprs_sgsn.c
@@ -90,47 +90,18 @@ static const struct rate_ctr_group_desc pdpctx_ctrg_desc = {
 	.class_id = OSMO_STATS_CLASS_SUBSCRIBER,
 };
 
-/* 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)
 {
 	struct sgsn_mm_ctx *ctx;
-	int tlli_type;
 
 	llist_for_each_entry(ctx, &sgsn_mm_ctxts, list) {
-		if (tlli == ctx->tlli &&
+		if ((tlli == ctx->tlli || tlli == ctx->tlli_new) &&
 		    gprs_ra_id_equals(raid, &ctx->ra))
 			return ctx;
 	}
 
-	tlli_type = gprs_tlli_type(tlli);
-	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)) {
-				ctx->tlli = tlli;
-				return ctx;
-			}
-		}
-		break;
-	case TLLI_FOREIGN:
-		llist_for_each_entry(ctx, &sgsn_mm_ctxts, list) {
-			if (tlli == tlli_foreign(ctx->tlli) &&
-			    gprs_ra_id_equals(raid, &ctx->ra))
-				return ctx;
-		}
-		break;
-	default:
-		break;
-	}
-
 	return NULL;
 }
 
diff --git a/openbsc/tests/sgsn/sgsn_test.c b/openbsc/tests/sgsn/sgsn_test.c
index 6d7ba38b7..2098972bd 100644
--- a/openbsc/tests/sgsn/sgsn_test.c
+++ b/openbsc/tests/sgsn/sgsn_test.c
@@ -1607,7 +1607,7 @@ static void test_gmm_cancel(void)
  */
 static void test_gmm_ptmsi_allocation(void)
 {
-	struct gprs_ra_id raid = { 0, };
+	struct gprs_ra_id raid = {332, 112, 16464, 96};
 	struct sgsn_mm_ctx *ctx = NULL;
 	struct sgsn_mm_ctx *ictx;
 	uint32_t foreign_tlli;