[M] Change in osmo-sgsn[master]: routing area: introduce ran_type on the RA - gerrit-log

13 Aug 2025

lynxis lazus has submitted this change. ( https://gerrit.osmocom.org/c/osmo-sgsn/+/40688?usp=email )
Change subject: routing area: introduce ran_type on the RA
......................................................................
routing area: introduce ran_type on the RA
A Routing Area should be uniquely identified by the RAI.
Following this, it is forbidden to have a RAI which is valid
in both, GERAN and UTRAN.
Change-Id: I59c35f1a4912ff11574bb31e4fe424816993548c
---
M include/osmocom/sgsn/gprs_routing_area.h
M src/sgsn/gprs_routing_area.c
M tests/gprs_routing_area/gprs_routing_area_test.c
3 files changed, 90 insertions(+), 36 deletions(-)
Approvals:
  pespin: Looks good to me, but someone else must approve
  Jenkins Builder: Verified
  lynxis lazus: Looks good to me, approved
  daniel: Looks good to me, but someone else must approve

diff --git a/include/osmocom/sgsn/gprs_routing_area.h b/include/osmocom/sgsn/gprs_routing_area.h
index caaed47..020ee17 100644
--- a/include/osmocom/sgsn/gprs_routing_area.h
+++ b/include/osmocom/sgsn/gprs_routing_area.h
@@ -6,6 +6,7 @@
 #include <stdint.h>
#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/utils.h>
 #include <osmocom/gsm/gsm23003.h>
struct sgsn_instance;
@@ -16,18 +17,35 @@
    struct llist_head ra_list;
 };
+enum sgsn_ra_ran_type {
+	RA_TYPE_GERAN_Gb,
+	RA_TYPE_UTRAN_Iu,
+};
+
+extern const struct value_string sgsn_ra_ran_type_names[];
+
 struct sgsn_ra {
    /* Entry in sgsn_ra_global->ra_list */
    struct llist_head list;
struct osmo_routing_area_id rai;
-	/* cells contains a list of sgsn_ra_cells which are alive */
-	struct llist_head cells;
-};
-enum sgsn_ra_ran_type {
-	RA_TYPE_GERAN_Gb,
-	RA_TYPE_UTRAN_Iu,
+	/* For GERAN: every PCU is connected to the SGSN. It allows the SGSN to know every single cell.
+	 * For routing, the SGSN must know to which PCU a given cell is connected.
+	 * It is possible that more than one PCU serves the same Routing Area.
+	 *
+	 * For UTRAN: only the RNC (HNB via HNBGW) is communicating with the SGSN.
+	 * The SGSN doesn't know every cell, because they aren't accepted individually by the SGSN.
+	 * The SGSN only "knows" RAI/SAI if they have been used. In the future it would be a good idea to
+	 * allow configuring RA in the vty/config as well.
+	 * Similar to the GERAN Cell, but iu_client doesn't notify us for every given SAI, only for RAC.
+	 * Further the SGSN doesn't get informed about Service Area and can't relate the SAI to a given UE.
+	 * For UTRAN only do a LAC/RAC <> RNC relation and don't have a specific cell relation.
+	 */
+	enum sgsn_ra_ran_type ran_type;
+
+	/* GERAN/UTRAN: cells contains a list of sgsn_ra_cells which are alive */
+	struct llist_head cells_alive_list;
 };
struct sgsn_ra_cell {
@@ -55,7 +73,7 @@
void sgsn_ra_init(struct sgsn_instance *inst);
-struct sgsn_ra *sgsn_ra_alloc(const struct osmo_routing_area_id *rai);
+struct sgsn_ra *sgsn_ra_alloc(const struct osmo_routing_area_id *rai, enum sgsn_ra_ran_type ran_type);
 void sgsn_ra_free(struct sgsn_ra *ra);
 struct sgsn_ra_cell *sgsn_ra_cell_alloc_geran(struct sgsn_ra *ra, uint16_t cell_id, uint16_t nsei, uint16_t bvci);
 void sgsn_ra_cell_free(struct sgsn_ra_cell *cell);
@@ -72,6 +90,7 @@
 struct sgsn_ra_cell *sgsn_ra_get_cell_by_ra(const struct sgsn_ra *ra, uint16_t cell_id);
 struct sgsn_ra_cell *sgsn_ra_get_cell_by_gb(uint16_t nsei, uint16_t bvci);
 struct sgsn_ra *sgsn_ra_get_ra(const struct osmo_routing_area_id *ra_id);
+struct sgsn_ra *sgsn_ra_get_ra_geran(const struct osmo_routing_area_id *ra_id);
/*
diff --git a/src/sgsn/gprs_routing_area.c b/src/sgsn/gprs_routing_area.c
index 67b15ae..e215a68 100644
--- a/src/sgsn/gprs_routing_area.c
+++ b/src/sgsn/gprs_routing_area.c
@@ -23,6 +23,7 @@
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/core/logging.h>
 #include <osmocom/core/rate_ctr.h>
+#include <osmocom/core/utils.h>
 #include <osmocom/gsm/gsm48.h>
 #include <osmocom/sgsn/debug.h>
 #include <osmocom/sgsn/gprs_bssgp.h>
@@ -31,6 +32,12 @@
#include <osmocom/sgsn/gprs_routing_area.h>
+const struct value_string sgsn_ra_ran_type_names[] = {
+	{ RA_TYPE_GERAN_Gb,	"GERAN_Gb" },
+	{ RA_TYPE_UTRAN_Iu,	"UTRAN_Iu" },
+	{ 0,                    NULL },
+};
+
 static void _sgsn_ra_cell_free(struct sgsn_ra_cell *cell, bool drop_empty_ra)
 {
    struct sgsn_ra *ra;
@@ -48,7 +55,7 @@
    ra = cell->ra;
    talloc_free(cell);
-	if (llist_empty(&ra->cells))
+	if (llist_empty(&ra->cells_alive_list))
    	sgsn_ra_free(ra);
 }
@@ -64,7 +71,7 @@
    if (!ra)
    	return;
-	llist_for_each_entry_safe(cell, cell2, &ra->cells, list) {
+	llist_for_each_entry_safe(cell, cell2, &ra->cells_alive_list, list) {
    	_sgsn_ra_cell_free(cell, false);
    }
@@ -72,15 +79,16 @@
    talloc_free(ra);
 }
-struct sgsn_ra *sgsn_ra_alloc(const struct osmo_routing_area_id *rai)
+struct sgsn_ra *sgsn_ra_alloc(const struct osmo_routing_area_id *rai, enum sgsn_ra_ran_type ran_type)
 {
    struct sgsn_ra *ra;
    ra = talloc_zero(sgsn->routing_area, struct sgsn_ra);
    if (!ra)
    	return NULL;
-	INIT_LLIST_HEAD(&ra->cells);
+	INIT_LLIST_HEAD(&ra->cells_alive_list);
    ra->rai = *rai;
+	ra->ran_type = ran_type;
    llist_add(&ra->list, &sgsn->routing_area->ra_list);
    return ra;
 }
@@ -99,7 +107,7 @@
    cell->u.geran.bvci = bvci;
    cell->u.geran.nsei = nsei;
-	llist_add(&cell->list, &ra->cells);
+	llist_add(&cell->list, &ra->cells_alive_list);
return cell;
 }
@@ -115,6 +123,19 @@
    return NULL;
 }
+struct sgsn_ra *sgsn_ra_get_ra_geran(const struct osmo_routing_area_id *ra_id)
+{
+	struct sgsn_ra *ra = sgsn_ra_get_ra(ra_id);
+
+	if (!ra)
+		return ra;
+
+	if (ra->ran_type == RA_TYPE_GERAN_Gb)
+		return ra;
+
+	return NULL;
+}
+
 struct sgsn_ra_cell *sgsn_ra_get_cell_by_gb(uint16_t nsei, uint16_t bvci)
 {
    struct sgsn_ra *ra;
@@ -125,7 +146,10 @@
    	return NULL;
llist_for_each_entry(ra, &sgsn->routing_area->ra_list, list) {
-		llist_for_each_entry(cell, &ra->cells, list) {
+		if (ra->ran_type != RA_TYPE_GERAN_Gb)
+			continue;
+
+		llist_for_each_entry(cell, &ra->cells_alive_list, list) {
    		if (cell->ran_type != RA_TYPE_GERAN_Gb)
    			continue;
@@ -144,7 +168,7 @@
OSMO_ASSERT(cb);
-	llist_for_each_entry_safe(cell, tmp, &ra->cells, list) {
+	llist_for_each_entry_safe(cell, tmp, &ra->cells_alive_list, list) {
    	ret = cb(cell, cb_data);
    	switch (ret) {
    	case SGSN_RA_CB_CONT:
@@ -174,11 +198,15 @@
    return sgsn_ra_foreach_cell(ra, cb, cb_data);
 }
+/* valid for GERAN */
 struct sgsn_ra_cell *sgsn_ra_get_cell_by_ra(const struct sgsn_ra *ra, uint16_t cell_id)
 {
    struct sgsn_ra_cell *cell;
-	llist_for_each_entry(cell, &ra->cells, list) {
+	if (ra->ran_type != RA_TYPE_GERAN_Gb)
+		return NULL;
+
+	llist_for_each_entry(cell, &ra->cells_alive_list, list) {
    	if (cell->cell_id == cell_id)
    		return cell;
    }
@@ -186,6 +214,7 @@
    return NULL;
 }
+/* valid for GERAN */
 struct sgsn_ra_cell *sgsn_ra_get_cell_by_lai(const struct osmo_location_area_id *lai, uint16_t cell_id)
 {
    struct sgsn_ra *ra;
@@ -194,10 +223,13 @@
    /* This is a little bit in-efficient. A more performance way, but more complex would
     * adding a llist for LAC on top of the routing areas */
    llist_for_each_entry(ra, &sgsn->routing_area->ra_list, list) {
+		if (ra->ran_type != RA_TYPE_GERAN_Gb)
+			continue;
+
    	if (osmo_lai_cmp(&ra->rai.lac, lai) != 0)
    		continue;
-		llist_for_each_entry(cell, &ra->cells, list) {
+		llist_for_each_entry(cell, &ra->cells_alive_list, list) {
    		if (cell->cell_id == cell_id)
    			return cell;
    	}
@@ -206,7 +238,7 @@
    return NULL;
 }
-/*! Return the cell by searching for the RA, when found, search the cell within the RA
+/*! Return the GERAN cell by searching for the RA, when found, search the cell within the RA
  *
  * \param cgi_ps
  * \return the cell or NULL if not found
@@ -217,7 +249,7 @@
OSMO_ASSERT(cgi_ps);
-	ra = sgsn_ra_get_ra(&cgi_ps->rai);
+	ra = sgsn_ra_get_ra_geran(&cgi_ps->rai);
    if (!ra)
    	return NULL;
@@ -246,9 +278,10 @@
    OSMO_ASSERT(cgi_ps);
/* TODO: do we have to move all MS to GMM IDLE state when this happens for a alive cell which got reseted? */
-	ra = sgsn_ra_get_ra(&cgi_ps->rai);
+	ra = sgsn_ra_get_ra_geran(&cgi_ps->rai);
    if (!ra) {
-		ra = sgsn_ra_alloc(&cgi_ps->rai);
+		/* TODO: check for UTRAN rai when introducing UTRAN support */
+		ra = sgsn_ra_alloc(&cgi_ps->rai, RA_TYPE_GERAN_Gb);
    	if (!ra)
    		return -ENOMEM;
    	ra_created = true;
@@ -312,7 +345,10 @@
    bool found = false;
llist_for_each_entry_safe(ra, ra2, &sgsn->routing_area->ra_list, list) {
-		llist_for_each_entry_safe(cell, cell2, &ra->cells, list) {
+		if (ra->ran_type != RA_TYPE_GERAN_Gb)
+			continue;
+
+		llist_for_each_entry_safe(cell, cell2, &ra->cells_alive_list, list) {
    		if (cell->ran_type != RA_TYPE_GERAN_Gb)
    			continue;
@@ -322,9 +358,8 @@
    		}
    	}
-		if (llist_empty(&ra->cells))
+		if (llist_empty(&ra->cells_alive_list))
    		sgsn_ra_free(ra);
-
    }
return found ? 0 : -ENOENT;
@@ -338,11 +373,11 @@
rate_ctr_inc(rate_ctr_group_get_ctr(mmctx->ctrg, GMM_CTR_PAGING_PS));
-	ra = sgsn_ra_get_ra(ra_id);
+	ra = sgsn_ra_get_ra_geran(ra_id);
    if (!ra)
    	return -ENOENT;
-	llist_for_each_entry(cell, &ra->cells, list) {
+	llist_for_each_entry(cell, &ra->cells_alive_list, list) {
    	if (cell->ran_type == RA_TYPE_GERAN_Gb) {
    		sgsn_bssgp_page_ps_bvci(mmctx, cell->u.geran.nsei, cell->u.geran.bvci);
    		ret = 0;
diff --git a/tests/gprs_routing_area/gprs_routing_area_test.c b/tests/gprs_routing_area/gprs_routing_area_test.c
index e1aec0f..f1d5c16 100644
--- a/tests/gprs_routing_area/gprs_routing_area_test.c
+++ b/tests/gprs_routing_area/gprs_routing_area_test.c
@@ -75,7 +75,7 @@
    printf("Testing Routing Area create/free\n");
sgsn = sgsn_instance_alloc(tall_sgsn_ctx);
-	ra = sgsn_ra_alloc(&raid);
+	ra = sgsn_ra_alloc(&raid, RA_TYPE_GERAN_Gb);
    OSMO_ASSERT(ra);
    OSMO_ASSERT(llist_count(&sgsn->routing_area->ra_list) == 1);
@@ -105,26 +105,26 @@
    printf("Testing Routing Area create/free\n");
sgsn = sgsn_instance_alloc(tall_sgsn_ctx);
-	ra = sgsn_ra_alloc(&raid);
+	ra = sgsn_ra_alloc(&raid, RA_TYPE_GERAN_Gb);
    OSMO_ASSERT(ra);
    OSMO_ASSERT(llist_count(&sgsn->routing_area->ra_list) == 1);
cell_a = sgsn_ra_cell_alloc_geran(ra, cell_id, nsei, bvci);
    OSMO_ASSERT(cell_a);
    OSMO_ASSERT(llist_count(&sgsn->routing_area->ra_list) == 1);
-	OSMO_ASSERT(llist_count(&ra->cells) == 1);
+	OSMO_ASSERT(llist_count(&ra->cells_alive_list) == 1);
sgsn_ra_free(ra);
    OSMO_ASSERT(llist_empty(&sgsn->routing_area->ra_list));
-	ra = sgsn_ra_alloc(&raid);
+	ra = sgsn_ra_alloc(&raid, RA_TYPE_GERAN_Gb);
    OSMO_ASSERT(ra);
    OSMO_ASSERT(llist_count(&sgsn->routing_area->ra_list) == 1);
cell_a = sgsn_ra_cell_alloc_geran(ra, cell_id, nsei, bvci);
    OSMO_ASSERT(cell_a);
    OSMO_ASSERT(llist_count(&sgsn->routing_area->ra_list) == 1);
-	OSMO_ASSERT(llist_count(&ra->cells) == 1);
+	OSMO_ASSERT(llist_count(&ra->cells_alive_list) == 1);
sgsn_ra_free(ra);
    OSMO_ASSERT(llist_empty(&sgsn->routing_area->ra_list));
@@ -160,7 +160,7 @@
    printf("Testing Routing Area find\n");
sgsn = sgsn_instance_alloc(tall_sgsn_ctx);
-	ra_a = sgsn_ra_alloc(&ra_id);
+	ra_a = sgsn_ra_alloc(&ra_id, RA_TYPE_GERAN_Gb);
    OSMO_ASSERT(ra_a);
    OSMO_ASSERT(llist_count(&sgsn->routing_area->ra_list) == 1);
@@ -194,7 +194,7 @@
    cgi.cell_identity = cell_id_not_found;
    cgi_ps.cell_identity = cell_id_not_found;
-	ra_a = sgsn_ra_alloc(&ra_id);
+	ra_a = sgsn_ra_alloc(&ra_id, RA_TYPE_GERAN_Gb);
    OSMO_ASSERT(ra_a);
    OSMO_ASSERT(llist_count(&sgsn->routing_area->ra_list) == 1);
@@ -263,14 +263,14 @@
    printf("Testing Routing Area BSSGP BVC RESET IND\n");
sgsn = sgsn_instance_alloc(tall_sgsn_ctx);
-	ra_a = sgsn_ra_alloc(&ra_id);
+	ra_a = sgsn_ra_alloc(&ra_id, RA_TYPE_GERAN_Gb);
    OSMO_ASSERT(ra_a);
    OSMO_ASSERT(llist_count(&sgsn->routing_area->ra_list) == 1);
-	OSMO_ASSERT(llist_count(&ra_a->cells) == 0);
+	OSMO_ASSERT(llist_count(&ra_a->cells_alive_list) == 0);
rc = sgsn_ra_bvc_reset_ind(nsei, bvci, &cgi_ps);
    OSMO_ASSERT(rc == 0);
-	OSMO_ASSERT(llist_count(&ra_a->cells) == 1);
+	OSMO_ASSERT(llist_count(&ra_a->cells_alive_list) == 1);
cell_a = sgsn_ra_get_cell_by_cgi(&cgi);
    OSMO_ASSERT(cell_a);
@@ -324,7 +324,7 @@
    OSMO_ASSERT(rc == 0);
ra_a = sgsn_ra_get_ra(&cgi_ps.rai);
-	OSMO_ASSERT(llist_count(&ra_a->cells) == 1);
+	OSMO_ASSERT(llist_count(&ra_a->cells_alive_list) == 1);
rc = sgsn_ra_nsei_failure_ind(nsei);
    OSMO_ASSERT(rc == 0);
-- 
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Gerrit-MessageType: merged
Gerrit-Project: osmo-sgsn
Gerrit-Branch: master
Gerrit-Change-Id: I59c35f1a4912ff11574bb31e4fe424816993548c
Gerrit-Change-Number: 40688
Gerrit-PatchSet: 3
Gerrit-Owner: lynxis lazus lynxis@fe80.eu
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: daniel dwillmann@sysmocom.de
Gerrit-Reviewer: lynxis lazus lynxis@fe80.eu
Gerrit-Reviewer: pespin pespin@sysmocom.de
Gerrit-CC: fixeria vyanitskiy@sysmocom.de



    