sgsn: Remove tlli_foreign2local

Currently foreign TLLI are sometimes mapped to local TLLI in the
hope that they will match. This seems to sometimes introduce
inconsisties, possibly leading to a failing assertion in
_bssgp_tx_dl_ud.

This mapping should probably reduce the allocation of additional
LLME during routing area changes.

This commit removes tlli_foreign2local.

Sponsored-by: On-Waves ehf

2 files changed, 2 insertions, 28 deletions

diff --git a/openbsc/src/gprs/gprs_llc.c b/openbsc/src/gprs/gprs_llc.c
index 936354a09..4cf51631b 100644
--- a/openbsc/src/gprs/gprs_llc.c
+++ b/openbsc/src/gprs/gprs_llc.c
@@ -38,21 +38,6 @@
 
 static struct gprs_llc_llme *llme_alloc(uint32_t tlli);
 
-/* If the TLLI is foreign, return its local version */
-static inline uint32_t tlli_foreign2local(uint32_t tlli)
-{
-	uint32_t new_tlli;
-
-	if (gprs_tlli_type(tlli) == TLLI_FOREIGN) {
-		new_tlli = tlli | 0x40000000;
-		LOGP(DLLC, LOGL_NOTICE, "TLLI 0x%08x is foreign, converting to "
-			"local TLLI 0x%08x\n", tlli, new_tlli);
-	} else
-		new_tlli = tlli;
-
-	return new_tlli;
-}
-
 /* Entry function from upper level (LLC), asking us to transmit a BSSGP PDU
  * to a remote MS (identified by TLLI) at a BTS identified by its BVCI and NSEI */
 static int _bssgp_tx_dl_ud(struct msgb *msg, struct sgsn_mm_ctx *mmctx)
@@ -72,9 +57,7 @@ static int _bssgp_tx_dl_ud(struct msgb *msg, struct sgsn_mm_ctx *mmctx)
 
 		/* make sure we only send it to the right llme */
 		OSMO_ASSERT(msgb_tlli(msg) == mmctx->llme->tlli
-				|| msgb_tlli(msg) == mmctx->llme->old_tlli
-				|| tlli_foreign2local(msgb_tlli(msg)) == mmctx->llme->tlli
-				|| tlli_foreign2local(msgb_tlli(msg)) == mmctx->llme->old_tlli);
+				|| msgb_tlli(msg) == mmctx->llme->old_tlli);
 	}
 	memcpy(&dup.qos_profile, qos_profile_default,
 		sizeof(qos_profile_default));
@@ -175,10 +158,6 @@ struct gprs_llc_lle *gprs_lle_get_or_create(const uint32_t tlli, uint8_t sapi)
 	if (lle)
 		return lle;
 
-	lle = lle_by_tlli_sapi(tlli_foreign2local(tlli), sapi);
-	if (lle)
-		return lle;
-
 	LOGP(DLLC, LOGL_NOTICE, "LLC: unknown TLLI 0x%08x, "
 		"creating LLME on the fly\n", tlli);
 	llme = llme_alloc(tlli);
@@ -204,7 +183,7 @@ static struct gprs_llc_lle *lle_for_rx_by_tlli_sapi(const uint32_t tlli,
 
 	/* Maybe it is a routing area update but we already know this sapi? */
 	if (gprs_tlli_type(tlli) == TLLI_FOREIGN) {
-		lle = lle_by_tlli_sapi(tlli_foreign2local(tlli), sapi);
+		lle = lle_by_tlli_sapi(tlli, sapi);
 		if (lle) {
 			LOGP(DLLC, LOGL_NOTICE,
 				"LLC RX: Found a local entry for TLLI 0x%08x\n",
diff --git a/openbsc/tests/sgsn/sgsn_test.c b/openbsc/tests/sgsn/sgsn_test.c
index 859223f7a..01e94c72d 100644
--- a/openbsc/tests/sgsn/sgsn_test.c
+++ b/openbsc/tests/sgsn/sgsn_test.c
@@ -203,11 +203,9 @@ static void test_llme(void)
 {
 	struct gprs_llc_lle *lle, *lle_copy;
 	uint32_t local_tlli;
-	uint32_t foreign_tlli;
 
 	printf("Testing LLME allocations\n");
 	local_tlli = gprs_tmsi2tlli(0x234, TLLI_LOCAL);
-	foreign_tlli = gprs_tmsi2tlli(0x234, TLLI_FOREIGN);
 
 	/* initial state */
 	OSMO_ASSERT(count(gprs_llme_list()) == 0);
@@ -221,9 +219,6 @@ static void test_llme(void)
 	lle_copy = gprs_lle_get_or_create(local_tlli, 3);
 	OSMO_ASSERT(lle == lle_copy);
 	OSMO_ASSERT(count(gprs_llme_list()) == 1);
-	lle_copy = gprs_lle_get_or_create(foreign_tlli, 3);
-	OSMO_ASSERT(lle == lle_copy);
-	OSMO_ASSERT(count(gprs_llme_list()) == 1);
 
 	/* unassign which should delete it*/
 	gprs_llgmm_assign(lle->llme, lle->llme->tlli, 0xffffffff, GPRS_ALGO_GEA0, NULL);