sgsn: Remove the "permanent" subscriber cache

The subscriber cache would help in case:

  * GPRS DETACH, GPRS ATTACH. In that case we might still
  have some cached authentication tuples we avoid another
  sendAuthenticationInfo request.

  * After a detach the cache expiry would make sure to
  eventually send a purgeMS to the HLR (which might be
  ignored).

At the same time to make the cache work we will need to
make sure to start and stop timers. In case we don't
start we might accumulate subscribers. I am afraid that
the above two benefits do not outweight the complexity
of this implementation.

5 files changed, 15 insertions, 192 deletions

diff --git a/openbsc/include/openbsc/gprs_sgsn.h b/openbsc/include/openbsc/gprs_sgsn.h
index 7940e1dc1..79df21be0 100644
--- a/openbsc/include/openbsc/gprs_sgsn.h
+++ b/openbsc/include/openbsc/gprs_sgsn.h
@@ -284,8 +284,6 @@ struct sgsn_subscriber_data {
 	struct gsm_auth_tuple	auth_triplets[5];
 	int			auth_triplets_updated;
 	int			error_cause;
-	struct osmo_timer_list	timer;
-	int			retries;
 	enum sgsn_subscriber_proc blocked_by;
 };
 
diff --git a/openbsc/include/openbsc/sgsn.h b/openbsc/include/openbsc/sgsn.h
index 4bd412750..7d3a68c43 100644
--- a/openbsc/include/openbsc/sgsn.h
+++ b/openbsc/include/openbsc/sgsn.h
@@ -7,8 +7,6 @@
 #include <osmocom/gprs/gprs_ns.h>
 #include <openbsc/gprs_sgsn.h>
 
-#define SGSN_TIMEOUT_NEVER (-1)
-
 struct gprs_gsup_client;
 
 enum sgsn_auth_policy {
@@ -33,8 +31,6 @@ struct sgsn_config {
 	struct sockaddr_in gsup_server_addr;
 	int gsup_server_port;
 
-	int subscriber_expiry_timeout;
-
 	int require_authentication;
 	int require_update_location;
 };
diff --git a/openbsc/src/gprs/gprs_subscriber.c b/openbsc/src/gprs/gprs_subscriber.c
index 5bde6a090..d6d874b0b 100644
--- a/openbsc/src/gprs/gprs_subscriber.c
+++ b/openbsc/src/gprs/gprs_subscriber.c
@@ -89,77 +89,11 @@ static int check_blocking(
 
 static void abort_blocking_procedure(struct gsm_subscriber *subscr)
 {
-	/* Best effort, stop retries at least */
-	subscr->sgsn_data->retries = SGSN_SUBSCR_MAX_RETRIES;
+	/* reset something */
 }
 
-static void sgsn_subscriber_timeout_cb(void *subscr_);
 int gprs_subscr_purge(struct gsm_subscriber *subscr);
 
-void gprs_subscr_stop_timer(struct gsm_subscriber *subscr)
-{
-	if (subscr->sgsn_data->timer.data) {
-		osmo_timer_del(&subscr->sgsn_data->timer);
-		subscr->sgsn_data->timer.cb = NULL;
-		OSMO_ASSERT(subscr->sgsn_data->timer.data == subscr);
-		subscr->sgsn_data->timer.data = NULL;
-		subscr_put(subscr);
-	}
-}
-
-void gprs_subscr_start_timer(struct gsm_subscriber *subscr, unsigned seconds)
-{
-	if (!subscr->sgsn_data->timer.data) {
-		subscr->sgsn_data->timer.cb = sgsn_subscriber_timeout_cb;
-		subscr->sgsn_data->timer.data = subscr_get(subscr);
-		subscr->sgsn_data->retries = 0;
-	}
-
-	osmo_timer_schedule(&subscr->sgsn_data->timer, seconds, 0);
-}
-
-static void sgsn_subscriber_timeout_cb(void *subscr_)
-{
-	struct gsm_subscriber *subscr = subscr_;
-
-	LOGGSUBSCRP(LOGL_INFO, subscr,
-		    "Expired, deleting subscriber entry\n");
-
-	subscr_get(subscr);
-
-	/* Check, whether to cleanup immediately */
-	if (!(subscr->flags & GPRS_SUBSCRIBER_ENABLE_PURGE) ||
-	    subscr->sgsn_data->retries >= SGSN_SUBSCR_MAX_RETRIES)
-		goto force_cleanup;
-
-	/* Send a 'purge MS' message to the HLR */
-	if (gprs_subscr_purge(subscr) < 0)
-		goto force_cleanup;
-
-	/* Purge request has been sent */
-
-	/* Check, whether purge is still enabled */
-	if (!(subscr->flags & GPRS_SUBSCRIBER_ENABLE_PURGE))
-		goto force_cleanup;
-
-	/* Make sure this will be tried again if there is no response in time */
-	subscr->sgsn_data->retries += 1;
-	gprs_subscr_start_timer(subscr, SGSN_SUBSCR_RETRY_INTERVAL);
-	subscr_put(subscr);
-	return;
-
-force_cleanup:
-	/* Make sure to clear blocking */
-	if (check_blocking(subscr, SGSN_SUBSCR_PROC_PURGE))
-		subscr->sgsn_data->blocked_by = SGSN_SUBSCR_PROC_NONE;
-
-	/* Make sure, the timer is cleaned up */
-	subscr->keep_in_ram = 0;
-	gprs_subscr_stop_timer(subscr);
-	/* The subscr is freed now, if the timer was the last user */
-	subscr_put(subscr);
-}
-
 static struct sgsn_subscriber_data *sgsn_subscriber_data_alloc(void *ctx)
 {
 	struct sgsn_subscriber_data *sdata;
@@ -185,9 +119,6 @@ struct gsm_subscriber *gprs_subscr_get_or_create(const char *imsi)
 
 	if (!subscr->sgsn_data)
 		subscr->sgsn_data = sgsn_subscriber_data_alloc(subscr);
-
-	gprs_subscr_stop_timer(subscr);
-
 	return subscr;
 }
 
@@ -204,16 +135,12 @@ void gprs_subscr_delete(struct gsm_subscriber *subscr)
 		subscr->sgsn_data->mm = NULL;
 	}
 
-	if ((subscr->flags & GPRS_SUBSCRIBER_CANCELLED) ||
-	    (subscr->flags & GSM_SUBSCRIBER_FIRST_CONTACT)) {
-		subscr->keep_in_ram = 0;
-		gprs_subscr_stop_timer(subscr);
-	} else if (sgsn->cfg.subscriber_expiry_timeout != SGSN_TIMEOUT_NEVER) {
-		gprs_subscr_start_timer(subscr, sgsn->cfg.subscriber_expiry_timeout);
-	} else {
-		subscr->keep_in_ram = 1;
+	if (subscr->flags & GPRS_SUBSCRIBER_ENABLE_PURGE) {
+		gprs_subscr_purge(subscr);
+		subscr->flags &= ~GPRS_SUBSCRIBER_ENABLE_PURGE;
 	}
 
+	subscr->keep_in_ram = 0;
 	subscr_put(subscr);
 }
 
@@ -224,7 +151,6 @@ void gprs_subscr_put_and_cancel(struct gsm_subscriber *subscr)
 	subscr->flags &= ~GPRS_SUBSCRIBER_ENABLE_PURGE;
 
 	gprs_subscr_update(subscr);
-
 	gprs_subscr_delete(subscr);
 }
 
diff --git a/openbsc/src/gprs/sgsn_vty.c b/openbsc/src/gprs/sgsn_vty.c
index 18d997b00..b4e1150e6 100644
--- a/openbsc/src/gprs/sgsn_vty.c
+++ b/openbsc/src/gprs/sgsn_vty.c
@@ -151,10 +151,6 @@ static int config_write_sgsn(struct vty *vty)
 	llist_for_each_entry(acl, &g_cfg->imsi_acl, list)
 		vty_out(vty, " imsi-acl add %s%s", acl->imsi, VTY_NEWLINE);
 
-	if (g_cfg->subscriber_expiry_timeout != SGSN_TIMEOUT_NEVER)
-		vty_out(vty, " subscriber-expiry-timeout %d%s",
-			g_cfg->subscriber_expiry_timeout, VTY_NEWLINE);
-
 	return CMD_SUCCESS;
 }
 
@@ -406,7 +402,6 @@ static void subscr_dump_full_vty(struct vty *vty, struct gsm_subscriber *subscr,
 	char expire_time[200];
 	struct gsm_auth_tuple *at;
 	int at_idx;
-	struct timeval tv;
 
 	vty_out(vty, "    ID: %llu, Authorized: %d%s", subscr->id,
 		subscr->authorized, VTY_NEWLINE);
@@ -452,17 +447,6 @@ static void subscr_dump_full_vty(struct vty *vty, struct gsm_subscriber *subscr,
 		vty_out(vty, "    Expiration Time: %s%s", expire_time, VTY_NEWLINE);
 	}
 
-	/* print the expiration time if the timer is active */
-	if (osmo_timer_pending(&subscr->sgsn_data->timer)) {
-		osmo_timer_remaining(&subscr->sgsn_data->timer, NULL, &tv);
-		strftime(expire_time, sizeof(expire_time),
-			 "%a, %d %b %Y %T %z",
-			 localtime(&subscr->sgsn_data->timer.timeout.tv_sec));
-		expire_time[sizeof(expire_time) - 1] = '\0';
-		vty_out(vty, "    Expires in: %ds (%s)%s",
-			(int)tv.tv_sec, expire_time, VTY_NEWLINE);
-	}
-
 	if (subscr->flags)
 		vty_out(vty, "    Flags: %s%s%s%s%s%s",
 			subscr->flags & GSM_SUBSCRIBER_FIRST_CONTACT ?
@@ -703,25 +687,6 @@ DEFUN(cfg_gsup_remote_port, cfg_gsup_remote_port_cmd,
 	return CMD_SUCCESS;
 }
 
-DEFUN(cfg_subscriber_expiry_timeout, cfg_subscriber_expiry_timeout_cmd,
-	"subscriber-expiry-timeout <0-999999>",
-	"Set the expiry time for unused subscriber entries\n"
-	"Expiry time in seconds\n")
-{
-	g_cfg->subscriber_expiry_timeout = atoi(argv[0]);
-
-	return CMD_SUCCESS;
-}
-
-DEFUN(cfg_no_subscriber_expiry_timeout, cfg_no_subscriber_expiry_timeout_cmd,
-	"no subscriber-expiry-timeout",
-	NO_STR "Set the expiry time for unused subscriber entries\n")
-{
-	g_cfg->subscriber_expiry_timeout = atoi(argv[0]);
-
-	return CMD_SUCCESS;
-}
-
 int sgsn_vty_init(void)
 {
 	install_element_ve(&show_sgsn_cmd);
@@ -748,8 +713,6 @@ int sgsn_vty_init(void)
 	install_element(SGSN_NODE, &cfg_auth_policy_cmd);
 	install_element(SGSN_NODE, &cfg_gsup_remote_ip_cmd);
 	install_element(SGSN_NODE, &cfg_gsup_remote_port_cmd);
-	install_element(SGSN_NODE, &cfg_subscriber_expiry_timeout_cmd);
-	install_element(SGSN_NODE, &cfg_no_subscriber_expiry_timeout_cmd);
 
 	return 0;
 }
diff --git a/openbsc/tests/sgsn/sgsn_test.c b/openbsc/tests/sgsn/sgsn_test.c
index 1ae94b0dd..34ad6473f 100644
--- a/openbsc/tests/sgsn/sgsn_test.c
+++ b/openbsc/tests/sgsn/sgsn_test.c
@@ -46,7 +46,6 @@ static struct sgsn_instance sgsn_inst = {
 	.cfg = {
 		.gtp_statedir = "./",
 		.auth_policy = SGSN_AUTH_POLICY_CLOSED,
-		.subscriber_expiry_timeout = SGSN_TIMEOUT_NEVER,
 	},
 };
 struct sgsn_instance *sgsn = &sgsn_inst;
@@ -218,9 +217,8 @@ static void show_subscrs(FILE *out)
 
 	llist_for_each_entry(subscr, &active_subscribers, entry) {
 		fprintf(out, "  Subscriber: %s, "
-			"use count: %d, keep: %d, timer: %d\n",
-			subscr->imsi, subscr->use_count, subscr->keep_in_ram,
-			osmo_timer_pending(&subscr->sgsn_data->timer));
+			"use count: %d\n",
+			subscr->imsi, subscr->use_count);
 	}
 }
 
@@ -237,7 +235,6 @@ static void test_subscriber(void)
 	const char *imsi1 = "1234567890";
 	const char *imsi2 = "9876543210";
 	const char *imsi3 = "5656565656";
-	int saved_expiry_timeout = sgsn->cfg.subscriber_expiry_timeout;
 
 	update_subscriber_data_cb = my_dummy_sgsn_update_subscriber_data;
 
@@ -271,25 +268,12 @@ static void test_subscriber(void)
 	gprs_subscr_update(s1);
 	OSMO_ASSERT(last_updated_subscr == s1);
 
-	/* Because of the update, it won't be freed on delete now */
+	/* There is no subscriber cache. Verify it */
 	gprs_subscr_delete(s1);
+	s1 = NULL;
 	sfound = gprs_subscr_get_by_imsi(imsi1);
-	OSMO_ASSERT(sfound != NULL);
-	s1 = sfound;
+	OSMO_ASSERT(sfound == NULL);
 
-	/* Cancel it, so that delete will free it.
-	 * Refcount it to make sure s1 won't be freed here */
-	last_updated_subscr = NULL;
-	gprs_subscr_put_and_cancel(subscr_get(s1));
-	OSMO_ASSERT(last_updated_subscr == s1);
-
-	/* Cancelled entries are still being found */
-	assert_subscr(s1, imsi1);
-
-	/* Free entry 1 (GPRS_SUBSCRIBER_CANCELLED is set) */
-	gprs_subscr_delete(s1);
-	s1 = NULL;
-	OSMO_ASSERT(gprs_subscr_get_by_imsi(imsi1) == NULL);
 	assert_subscr(s2, imsi2);
 	assert_subscr(s3, imsi3);
 
@@ -301,24 +285,9 @@ static void test_subscriber(void)
 	assert_subscr(s3, imsi3);
 
 	/* Try to delete entry 3 */
-	OSMO_ASSERT(sgsn->cfg.subscriber_expiry_timeout == SGSN_TIMEOUT_NEVER);
 	gprs_subscr_delete(s3);
-	assert_subscr(s3, imsi3);
-	/* Process timeouts, this shouldn't delete s3 (SGSN_TIMEOUT_NEVER) */
-	osmo_timers_update();
-	assert_subscr(s3, imsi3);
-	s3 = subscr_get(s3);
-
-	/* Free entry 3 (TIMEOUT == 0) */
-	sgsn->cfg.subscriber_expiry_timeout = 0;
-	gprs_subscr_delete(s3);
-	assert_subscr(s3, imsi3);
-	/* Process timeouts, this should delete s3 */
-	osmo_timers_update();
-	OSMO_ASSERT(gprs_subscr_get_by_imsi(imsi1) == NULL);
-	OSMO_ASSERT(gprs_subscr_get_by_imsi(imsi2) == NULL);
+	s3 = NULL;
 	OSMO_ASSERT(gprs_subscr_get_by_imsi(imsi3) == NULL);
-	sgsn->cfg.subscriber_expiry_timeout = saved_expiry_timeout;
 
 	OSMO_ASSERT(llist_empty(&active_subscribers));
 
@@ -1053,18 +1022,6 @@ int my_subscr_request_auth_info(struct sgsn_mm_ctx *mmctx) {
 	return 0;
 };
 
-static void cleanup_subscr_by_imsi(const char *imsi)
-{
-	struct gsm_subscriber *subscr;
-
-	subscr = gprs_subscr_get_by_imsi(imsi);
-	OSMO_ASSERT(subscr != NULL);
-	subscr->keep_in_ram = 0;
-	subscr_put(subscr);
-	subscr = gprs_subscr_get_by_imsi(imsi);
-	OSMO_ASSERT(subscr == NULL);
-}
-
 static void test_gmm_attach_subscr(void)
 {
 	const enum sgsn_auth_policy saved_auth_policy = sgsn->cfg.auth_policy;
@@ -1076,13 +1033,10 @@ static void test_gmm_attach_subscr(void)
 
 	subscr = gprs_subscr_get_or_create("123456789012345");
 	subscr->authorized = 1;
-	subscr->keep_in_ram = 1;
-	subscr_put(subscr);
 
 	printf("Auth policy 'remote': ");
 	test_gmm_attach(0);
-
-	cleanup_subscr_by_imsi("123456789012345");
+	subscr_put(subscr);
 	assert_no_subscrs();
 
 	sgsn->cfg.auth_policy = saved_auth_policy;
@@ -1111,15 +1065,12 @@ static void test_gmm_attach_subscr_fake_auth(void)
 
 	subscr = gprs_subscr_get_or_create("123456789012345");
 	subscr->authorized = 1;
-	subscr->keep_in_ram = 1;
 	sgsn->cfg.require_authentication = 1;
 	sgsn->cfg.require_update_location = 1;
-	subscr_put(subscr);
 
 	printf("Auth policy 'remote', auth faked: ");
 	test_gmm_attach(0);
-
-	cleanup_subscr_by_imsi("123456789012345");
+	subscr_put(subscr);
 	assert_no_subscrs();
 
 	sgsn->cfg.auth_policy = saved_auth_policy;
@@ -1154,16 +1105,13 @@ static void test_gmm_attach_subscr_real_auth(void)
 
 	subscr = gprs_subscr_get_or_create("123456789012345");
 	subscr->authorized = 1;
-	subscr->keep_in_ram = 1;
 	sgsn->cfg.require_authentication = 1;
 	sgsn->cfg.require_update_location = 1;
-	subscr_put(subscr);
 
 	printf("Auth policy 'remote', triplet based auth: ");
 
 	test_gmm_attach(0);
-
-	cleanup_subscr_by_imsi("123456789012345");
+	subscr_put(subscr);
 	assert_no_subscrs();
 
 	sgsn->cfg.auth_policy = saved_auth_policy;
@@ -1249,8 +1197,6 @@ static void test_gmm_attach_subscr_gsup_auth(int retry)
 
 	printf("Auth policy 'remote', GSUP based auth: ");
 	test_gmm_attach(retry);
-
-	cleanup_subscr_by_imsi("123456789012345");
 	assert_no_subscrs();
 
 	sgsn->cfg.auth_policy = saved_auth_policy;
@@ -1317,7 +1263,6 @@ static void test_gmm_attach_subscr_real_gsup_auth(int retry)
 	struct gsm_subscriber *subscr;
 
 	sgsn_inst.cfg.auth_policy = SGSN_AUTH_POLICY_REMOTE;
-	sgsn_inst.cfg.subscriber_expiry_timeout = 0;
 	gprs_gsup_client_send_cb = my_gprs_gsup_client_send;
 
 	sgsn->gsup_client = talloc_zero(tall_bsc_ctx, struct gprs_gsup_client);
@@ -1331,15 +1276,10 @@ static void test_gmm_attach_subscr_real_gsup_auth(int retry)
 	test_gmm_attach(retry);
 
 	subscr = gprs_subscr_get_by_imsi("123456789012345");
-	OSMO_ASSERT(subscr != NULL);
-	gprs_subscr_delete(subscr);
-
-	osmo_timers_update();
-
+	OSMO_ASSERT(subscr == NULL);
 	assert_no_subscrs();
 
 	sgsn->cfg.auth_policy = saved_auth_policy;
-	sgsn_inst.cfg.subscriber_expiry_timeout = SGSN_TIMEOUT_NEVER;
 	gprs_gsup_client_send_cb = __real_gprs_gsup_client_send;
 	upd_loc_skip = 0;
 	auth_info_skip = 0;