bsc_subscriber: Introduce bsc_subscriber_store object

This allows keeping the bsc_subscriber storage internals outside of main
gsm_network code, while easily allowing making the internal
implementation more complex (in order to optimize it in a follow-up
commit).
It is also nice since we get rid of uncommon procedures being used in
this code, like allocating an llist directly as a talloc context, etc.

Change-Id: I616e8872af4ac63a6985f8900909e324ba889192

7 files changed, 71 insertions, 57 deletions

diff --git a/include/osmocom/bsc/bsc_subscriber.h b/include/osmocom/bsc/bsc_subscriber.h
index a86ea5f8b..7ec457bf4 100644
--- a/include/osmocom/bsc/bsc_subscriber.h
+++ b/include/osmocom/bsc/bsc_subscriber.h
@@ -12,8 +12,15 @@
 struct log_target;
 struct gsm_bts;
 
+struct bsc_subscr_store {
+	struct llist_head bsub_list; /* list containing "struct bsc_subscr" */
+};
+
+struct bsc_subscr_store *bsc_subscr_store_alloc(void *ctx);
+
 struct bsc_subscr {
-	struct llist_head entry;
+	struct bsc_subscr_store *store; /* backpointer to "struct bsc_subscr_store" */
+	struct llist_head entry; /* entry in (struct bsc_subscr_store)->bsub_list */
 	struct osmo_use_count use_count;
 
 	char imsi[GSM23003_IMSI_MAX_DIGITS+1];
@@ -28,16 +35,17 @@ struct bsc_subscr {
 const char *bsc_subscr_name(struct bsc_subscr *bsub);
 const char *bsc_subscr_id(struct bsc_subscr *bsub);
 
-struct bsc_subscr *bsc_subscr_find_or_create_by_imsi(struct llist_head *list,
+struct bsc_subscr *bsc_subscr_find_or_create_by_imsi(struct bsc_subscr_store *bsubst,
 						     const char *imsi,
 						     const char *use_token);
-struct bsc_subscr *bsc_subscr_find_or_create_by_tmsi(struct llist_head *list,
+struct bsc_subscr *bsc_subscr_find_or_create_by_tmsi(struct bsc_subscr_store *bsubst,
 						     uint32_t tmsi,
 						     const char *use_token);
-struct bsc_subscr *bsc_subscr_find_or_create_by_mi(struct llist_head *list, const struct osmo_mobile_identity *mi,
+struct bsc_subscr *bsc_subscr_find_or_create_by_mi(struct bsc_subscr_store *bsubst,
+						   const struct osmo_mobile_identity *mi,
 						   const char *use_token);
 
-struct bsc_subscr *bsc_subscr_find_by_imsi(struct llist_head *list,
+struct bsc_subscr *bsc_subscr_find_by_imsi(struct bsc_subscr_store *bsubst,
 					   const char *imsi,
 					   const char *use_token);
 
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index 0c5b485a3..dc7ee3f89 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -954,13 +954,8 @@ struct gsm_network {
 	 * OsmoMSC, this should be tied to the location area code (LAC). */
 	struct gsm_tz tz;
 
-	/* List of all struct bsc_subscr used in libbsc. This llist_head is
-	 * allocated so that the llist_head pointer itself can serve as a
-	 * talloc context (useful to not have to pass the entire gsm_network
-	 * struct to the bsc_subscr_* API, and for bsc_susbscr unit tests to
-	 * not require gsm_data.h). In an MSC-without-BSC environment, this
-	 * pointer is NULL to indicate absence of a bsc_subscribers list. */
-	struct llist_head *bsc_subscribers;
+	/* Keeps track of struct bsc_subcr. */
+	struct bsc_subscr_store *bsc_subscribers;
 
 	/* Timer for periodic channel load measurements to maintain each BTS's T3122. */
 	struct osmo_timer_list t3122_chan_load_timer;
diff --git a/src/osmo-bsc/bsc_subscriber.c b/src/osmo-bsc/bsc_subscriber.c
index 6815ab550..65c5c8764 100644
--- a/src/osmo-bsc/bsc_subscriber.c
+++ b/src/osmo-bsc/bsc_subscriber.c
@@ -65,14 +65,27 @@ static int bsub_use_cb(struct osmo_use_count_entry *e, int32_t old_use_count, co
 	return 0;
 }
 
-static struct bsc_subscr *bsc_subscr_alloc(struct llist_head *list)
+struct bsc_subscr_store *bsc_subscr_store_alloc(void *ctx)
+{
+	struct bsc_subscr_store *bsubst;
+
+	bsubst = talloc_zero(ctx, struct bsc_subscr_store);
+	if (!bsubst)
+		return NULL;
+
+	INIT_LLIST_HEAD(&bsubst->bsub_list);
+	return bsubst;
+}
+
+static struct bsc_subscr *bsc_subscr_alloc(struct bsc_subscr_store *bsubst)
 {
 	struct bsc_subscr *bsub;
 
-	bsub = talloc_zero(list, struct bsc_subscr);
+	bsub = talloc_zero(bsubst, struct bsc_subscr);
 	if (!bsub)
 		return NULL;
 
+	bsub->store = bsubst;
 	bsub->tmsi = GSM_RESERVED_TMSI;
 	bsub->use_count = (struct osmo_use_count){
 		.talloc_object = bsub,
@@ -80,12 +93,12 @@ static struct bsc_subscr *bsc_subscr_alloc(struct llist_head *list)
 	};
 	INIT_LLIST_HEAD(&bsub->active_paging_requests);
 
-	llist_add_tail(&bsub->entry, list);
+	llist_add_tail(&bsub->entry, &bsubst->bsub_list);
 
 	return bsub;
 }
 
-struct bsc_subscr *bsc_subscr_find_by_imsi(struct llist_head *list,
+struct bsc_subscr *bsc_subscr_find_by_imsi(struct bsc_subscr_store *bsubst,
 					   const char *imsi,
 					   const char *use_token)
 {
@@ -94,7 +107,7 @@ struct bsc_subscr *bsc_subscr_find_by_imsi(struct llist_head *list,
 	if (!imsi || !*imsi)
 		return NULL;
 
-	llist_for_each_entry(bsub, list, entry) {
+	llist_for_each_entry(bsub, &bsubst->bsub_list, entry) {
 		if (!strcmp(bsub->imsi, imsi)) {
 			bsc_subscr_get(bsub, use_token);
 			return bsub;
@@ -103,7 +116,7 @@ struct bsc_subscr *bsc_subscr_find_by_imsi(struct llist_head *list,
 	return NULL;
 }
 
-static struct bsc_subscr *bsc_subscr_find_by_imei(struct llist_head *list,
+static struct bsc_subscr *bsc_subscr_find_by_imei(struct bsc_subscr_store *bsubst,
 						  const char *imei,
 						  const char *use_token)
 {
@@ -112,7 +125,7 @@ static struct bsc_subscr *bsc_subscr_find_by_imei(struct llist_head *list,
 	if (!imei || !*imei)
 		return NULL;
 
-	llist_for_each_entry(bsub, list, entry) {
+	llist_for_each_entry(bsub, &bsubst->bsub_list, entry) {
 		if (!strcmp(bsub->imei, imei)) {
 			bsc_subscr_get(bsub, use_token);
 			return bsub;
@@ -121,7 +134,7 @@ static struct bsc_subscr *bsc_subscr_find_by_imei(struct llist_head *list,
 	return NULL;
 }
 
-static struct bsc_subscr *bsc_subscr_find_by_tmsi(struct llist_head *list,
+static struct bsc_subscr *bsc_subscr_find_by_tmsi(struct bsc_subscr_store *bsubst,
 						  uint32_t tmsi,
 						  const char *use_token)
 {
@@ -130,7 +143,7 @@ static struct bsc_subscr *bsc_subscr_find_by_tmsi(struct llist_head *list,
 	if (tmsi == GSM_RESERVED_TMSI)
 		return NULL;
 
-	llist_for_each_entry(bsub, list, entry) {
+	llist_for_each_entry(bsub, &bsubst->bsub_list, entry) {
 		if (bsub->tmsi == tmsi) {
 			bsc_subscr_get(bsub, use_token);
 			return bsub;
@@ -153,15 +166,15 @@ void bsc_subscr_set_imei(struct bsc_subscr *bsub, const char *imei)
 	osmo_strlcpy(bsub->imei, imei, sizeof(bsub->imei));
 }
 
-struct bsc_subscr *bsc_subscr_find_or_create_by_imsi(struct llist_head *list,
+struct bsc_subscr *bsc_subscr_find_or_create_by_imsi(struct bsc_subscr_store *bsubst,
 						     const char *imsi,
 						     const char *use_token)
 {
 	struct bsc_subscr *bsub;
-	bsub = bsc_subscr_find_by_imsi(list, imsi, use_token);
+	bsub = bsc_subscr_find_by_imsi(bsubst, imsi, use_token);
 	if (bsub)
 		return bsub;
-	bsub = bsc_subscr_alloc(list);
+	bsub = bsc_subscr_alloc(bsubst);
 	if (!bsub)
 		return NULL;
 	bsc_subscr_set_imsi(bsub, imsi);
@@ -169,15 +182,15 @@ struct bsc_subscr *bsc_subscr_find_or_create_by_imsi(struct llist_head *list,
 	return bsub;
 }
 
-static struct bsc_subscr *bsc_subscr_find_or_create_by_imei(struct llist_head *list,
+static struct bsc_subscr *bsc_subscr_find_or_create_by_imei(struct bsc_subscr_store *bsubst,
 							    const char *imei,
 							    const char *use_token)
 {
 	struct bsc_subscr *bsub;
-	bsub = bsc_subscr_find_by_imei(list, imei, use_token);
+	bsub = bsc_subscr_find_by_imei(bsubst, imei, use_token);
 	if (bsub)
 		return bsub;
-	bsub = bsc_subscr_alloc(list);
+	bsub = bsc_subscr_alloc(bsubst);
 	if (!bsub)
 		return NULL;
 	bsc_subscr_set_imei(bsub, imei);
@@ -185,15 +198,15 @@ static struct bsc_subscr *bsc_subscr_find_or_create_by_imei(struct llist_head *l
 	return bsub;
 }
 
-struct bsc_subscr *bsc_subscr_find_or_create_by_tmsi(struct llist_head *list,
+struct bsc_subscr *bsc_subscr_find_or_create_by_tmsi(struct bsc_subscr_store *bsubst,
 						     uint32_t tmsi,
 						     const char *use_token)
 {
 	struct bsc_subscr *bsub;
-	bsub = bsc_subscr_find_by_tmsi(list, tmsi, use_token);
+	bsub = bsc_subscr_find_by_tmsi(bsubst, tmsi, use_token);
 	if (bsub)
 		return bsub;
-	bsub = bsc_subscr_alloc(list);
+	bsub = bsc_subscr_alloc(bsubst);
 	if (!bsub)
 		return NULL;
 	bsub->tmsi = tmsi;
@@ -201,18 +214,18 @@ struct bsc_subscr *bsc_subscr_find_or_create_by_tmsi(struct llist_head *list,
 	return bsub;
 }
 
-struct bsc_subscr *bsc_subscr_find_or_create_by_mi(struct llist_head *list, const struct osmo_mobile_identity *mi,
+struct bsc_subscr *bsc_subscr_find_or_create_by_mi(struct bsc_subscr_store *bsubst, const struct osmo_mobile_identity *mi,
 						   const char *use_token)
 {
 	if (!mi)
 		return NULL;
 	switch (mi->type) {
 	case GSM_MI_TYPE_IMSI:
-		return bsc_subscr_find_or_create_by_imsi(list, mi->imsi, use_token);
+		return bsc_subscr_find_or_create_by_imsi(bsubst, mi->imsi, use_token);
 	case GSM_MI_TYPE_IMEI:
-		return bsc_subscr_find_or_create_by_imei(list, mi->imei, use_token);
+		return bsc_subscr_find_or_create_by_imei(bsubst, mi->imei, use_token);
 	case GSM_MI_TYPE_TMSI:
-		return bsc_subscr_find_or_create_by_tmsi(list, mi->tmsi, use_token);
+		return bsc_subscr_find_or_create_by_tmsi(bsubst, mi->tmsi, use_token);
 	default:
 		return NULL;
 	}
diff --git a/src/osmo-bsc/bsc_vty.c b/src/osmo-bsc/bsc_vty.c
index c219ff453..e8608880a 100644
--- a/src/osmo-bsc/bsc_vty.c
+++ b/src/osmo-bsc/bsc_vty.c
@@ -3285,7 +3285,7 @@ DEFUN(show_subscr_all,
 	vty_out(vty, " IMSI             TMSI      Use%s", VTY_NEWLINE);
 	/*           " 001010123456789  ffffffff  1" */
 
-	llist_for_each_entry(bsc_subscr, bsc_gsmnet->bsc_subscribers, entry)
+	llist_for_each_entry(bsc_subscr, &bsc_gsmnet->bsc_subscribers->bsub_list, entry)
 		dump_one_sub(vty, bsc_subscr);
 
 	return CMD_SUCCESS;
diff --git a/src/osmo-bsc/net_init.c b/src/osmo-bsc/net_init.c
index 8a508dd61..5a7422c62 100644
--- a/src/osmo-bsc/net_init.c
+++ b/src/osmo-bsc/net_init.c
@@ -119,8 +119,7 @@ struct gsm_network *gsm_network_init(void *ctx)
 
 	INIT_LLIST_HEAD(&net->subscr_conns);
 
-	net->bsc_subscribers = talloc_zero(net, struct llist_head);
-	INIT_LLIST_HEAD(net->bsc_subscribers);
+	net->bsc_subscribers = bsc_subscr_store_alloc(net);
 
 	INIT_LLIST_HEAD(&net->bts_list);
 	net->num_bts = 0;
diff --git a/tests/subscr/bsc_subscr_test.c b/tests/subscr/bsc_subscr_test.c
index 14e069df9..27dc93e1d 100644
--- a/tests/subscr/bsc_subscr_test.c
+++ b/tests/subscr/bsc_subscr_test.c
@@ -29,7 +29,7 @@
 #include <stdlib.h>
 #include <inttypes.h>
 
-struct llist_head *bsc_subscribers;
+struct bsc_subscr_store *bsc_subscribers;
 
 #define VERBOSE_ASSERT(val, expect_op, fmt) \
 	do { \
@@ -61,26 +61,26 @@ static void test_bsc_subscr(void)
 	printf("Test BSC subscriber allocation and deletion\n");
 
 	/* Check for emptiness */
-	VERBOSE_ASSERT(llist_count(bsc_subscribers), == 0, "%d");
+	VERBOSE_ASSERT(llist_count(&bsc_subscribers->bsub_list), == 0, "%d");
 	OSMO_ASSERT(bsc_subscr_find_by_imsi(bsc_subscribers, imsi1, BSUB_USE) == NULL);
 	OSMO_ASSERT(bsc_subscr_find_by_imsi(bsc_subscribers, imsi2, BSUB_USE) == NULL);
 	OSMO_ASSERT(bsc_subscr_find_by_imsi(bsc_subscribers, imsi3, BSUB_USE) == NULL);
 
 	/* Allocate entry 1 */
 	s1 = bsc_subscr_find_or_create_by_imsi(bsc_subscribers, imsi1, BSUB_USE);
-	VERBOSE_ASSERT(llist_count(bsc_subscribers), == 1, "%d");
+	VERBOSE_ASSERT(llist_count(&bsc_subscribers->bsub_list), == 1, "%d");
 	assert_bsc_subscr(s1, imsi1);
-	VERBOSE_ASSERT(llist_count(bsc_subscribers), == 1, "%d");
+	VERBOSE_ASSERT(llist_count(&bsc_subscribers->bsub_list), == 1, "%d");
 	OSMO_ASSERT(bsc_subscr_find_by_imsi(bsc_subscribers, imsi2, BSUB_USE) == NULL);
 
 	/* Allocate entry 2 */
 	s2 = bsc_subscr_find_or_create_by_imsi(bsc_subscribers, imsi2, BSUB_USE);
 	s2->tmsi = 0x73517351;
-	VERBOSE_ASSERT(llist_count(bsc_subscribers), == 2, "%d");
+	VERBOSE_ASSERT(llist_count(&bsc_subscribers->bsub_list), == 2, "%d");
 
 	/* Allocate entry 3 */
 	s3 = bsc_subscr_find_or_create_by_imsi(bsc_subscribers, imsi3, BSUB_USE);
-	VERBOSE_ASSERT(llist_count(bsc_subscribers), == 3, "%d");
+	VERBOSE_ASSERT(llist_count(&bsc_subscribers->bsub_list), == 3, "%d");
 
 	/* Check entries */
 	assert_bsc_subscr(s1, imsi1);
@@ -90,7 +90,7 @@ static void test_bsc_subscr(void)
 	/* Free entry 1 */
 	bsc_subscr_put(s1, BSUB_USE);
 	s1 = NULL;
-	VERBOSE_ASSERT(llist_count(bsc_subscribers), == 2, "%d");
+	VERBOSE_ASSERT(llist_count(&bsc_subscribers->bsub_list), == 2, "%d");
 	OSMO_ASSERT(bsc_subscr_find_by_imsi(bsc_subscribers, imsi1, BSUB_USE) == NULL);
 
 	assert_bsc_subscr(s2, imsi2);
@@ -99,7 +99,7 @@ static void test_bsc_subscr(void)
 	/* Free entry 2 */
 	bsc_subscr_put(s2, BSUB_USE);
 	s2 = NULL;
-	VERBOSE_ASSERT(llist_count(bsc_subscribers), == 1, "%d");
+	VERBOSE_ASSERT(llist_count(&bsc_subscribers->bsub_list), == 1, "%d");
 	OSMO_ASSERT(bsc_subscr_find_by_imsi(bsc_subscribers, imsi1, BSUB_USE) == NULL);
 	OSMO_ASSERT(bsc_subscr_find_by_imsi(bsc_subscribers, imsi2, BSUB_USE) == NULL);
 	assert_bsc_subscr(s3, imsi3);
@@ -107,10 +107,10 @@ static void test_bsc_subscr(void)
 	/* Free entry 3 */
 	bsc_subscr_put(s3, BSUB_USE);
 	s3 = NULL;
-	VERBOSE_ASSERT(llist_count(bsc_subscribers), == 0, "%d");
+	VERBOSE_ASSERT(llist_count(&bsc_subscribers->bsub_list), == 0, "%d");
 	OSMO_ASSERT(bsc_subscr_find_by_imsi(bsc_subscribers, imsi3, BSUB_USE) == NULL);
 
-	OSMO_ASSERT(llist_empty(bsc_subscribers));
+	OSMO_ASSERT(llist_empty(&bsc_subscribers->bsub_list));
 }
 
 static const struct log_info_cat log_categories[] = {
@@ -137,8 +137,7 @@ int main()
 	log_set_print_category_hex(osmo_stderr_target, 0);
 	log_set_print_category(osmo_stderr_target, 1);
 
-	bsc_subscribers = talloc_zero(ctx, struct llist_head);
-	INIT_LLIST_HEAD(bsc_subscribers);
+	bsc_subscribers = bsc_subscr_store_alloc(ctx);
 
 	test_bsc_subscr();
 
diff --git a/tests/subscr/bsc_subscr_test.ok b/tests/subscr/bsc_subscr_test.ok
index 0f6a8be01..b82b09625 100644
--- a/tests/subscr/bsc_subscr_test.ok
+++ b/tests/subscr/bsc_subscr_test.ok
@@ -1,11 +1,11 @@
 Testing BSC subscriber core code.
 Test BSC subscriber allocation and deletion
-llist_count(bsc_subscribers) == 0
-llist_count(bsc_subscribers) == 1
-llist_count(bsc_subscribers) == 1
-llist_count(bsc_subscribers) == 2
-llist_count(bsc_subscribers) == 3
-llist_count(bsc_subscribers) == 2
-llist_count(bsc_subscribers) == 1
-llist_count(bsc_subscribers) == 0
+llist_count(&bsc_subscribers->bsub_list) == 0
+llist_count(&bsc_subscribers->bsub_list) == 1
+llist_count(&bsc_subscribers->bsub_list) == 1
+llist_count(&bsc_subscribers->bsub_list) == 2
+llist_count(&bsc_subscribers->bsub_list) == 3
+llist_count(&bsc_subscribers->bsub_list) == 2
+llist_count(&bsc_subscribers->bsub_list) == 1
+llist_count(&bsc_subscribers->bsub_list) == 0
 Done