Use libvlr in libmsc (large refactoring)

Original libvlr code is by Harald Welte <laforge@gnumonks.org>,
polished and tweaked by Neels Hofmeyr <nhofmeyr@sysmocom.de>.

This is a long series of development collapsed in one patch. The original
history may still be available as branch neels/vlr_orig.

TODO: This commit may be split in several smaller changes before merging to
master.

SMS:

The SQL based lookup of SMS for attached subscribers no longer works since the
SQL database no longer has the subscriber data. Replace with a round-robin on
the SMS recipient MSISDNs paired with a VLR subscriber RAM lookup whether the
subscriber is currently attached.

If there are many SMS for not-attached subscribers in the SMS database, this
will become inefficient: a DB hit returns a pending SMS, the RAM lookup will
reveal that the subscriber is not attached, after which the DB is hit for the
next SMS. It would become more efficient e.g. by having an MSISDN based hash
list for the VLR subscribers and by marking non-attached SMS recipients in the
SMS database so that they can be excluded with the SQL query already.

There is a sanity limit to do at most 100 db hits per attempt to find a pending
SMS. So if there are more than 100 stored SMS waiting for their recipients to
actually attach to the MSC, it may take more than one SMS queue trigger to
deliver SMS for subscribers that are actually attached.

This is not very beautiful, but is merely intended to carry us over to a time
when we have a proper separate SMSC entity.

Introduce gsm_subscriber_connection ref-counting in libmsc.

Related: OS#1592

Change-Id: I702ba504ce2de93507312c28eca8d11f09f4ee8b

1 files changed, 37 insertions, 276 deletions

diff --git a/openbsc/src/libmsc/gsm_subscriber.c b/openbsc/src/libmsc/gsm_subscriber.c
index 1a03cf76e..e9b2e0e5d 100644
--- a/openbsc/src/libmsc/gsm_subscriber.c
+++ b/openbsc/src/libmsc/gsm_subscriber.c
@@ -39,11 +39,10 @@
 #include <openbsc/signal.h>
 #include <openbsc/db.h>
 #include <openbsc/chan_alloc.h>
+#include <openbsc/vlr.h>
 
 void *tall_sub_req_ctx;
 
-extern struct llist_head *subscr_bsc_active_subscribers(void);
-
 int gsm48_secure_channel(struct gsm_subscriber_connection *conn, int key_seq,
                          gsm_cbfn *cb, void *cb_data);
 
@@ -62,31 +61,35 @@ struct subscr_request {
 	void *param;
 };
 
-static struct gsm_subscriber *get_subscriber(struct gsm_subscriber_group *sgrp,
-						int type, const char *ident)
+static struct bsc_subscr *vlr_subscr_to_bsc_sub(struct llist_head *bsc_subscribers,
+						struct vlr_subscr *vsub)
 {
-	struct gsm_subscriber *subscr = db_get_subscriber(type, ident);
-	if (subscr)
-		subscr->group = sgrp;
-	return subscr;
+	struct bsc_subscr *sub;
+	/* TODO MSC split -- creating a BSC subscriber directly from MSC data
+	 * structures in RAM. At some point the MSC will send a message to the
+	 * BSC instead. */
+	sub = bsc_subscr_find_or_create_by_imsi(bsc_subscribers, vsub->imsi);
+	sub->tmsi = vsub->tmsi;
+	sub->lac = vsub->lac;
+	return sub;
 }
 
 /*
  * We got the channel assigned and can now hand this channel
  * over to one of our callbacks.
  */
-static int subscr_paging_dispatch(unsigned int hooknum, unsigned int event,
-                                  struct msgb *msg, void *data, void *param)
+int subscr_paging_dispatch(unsigned int hooknum, unsigned int event,
+			   struct msgb *msg, void *data, void *param)
 {
 	struct subscr_request *request, *tmp;
 	struct gsm_subscriber_connection *conn = data;
-	struct gsm_subscriber *subscr = param;
+	struct vlr_subscr *vsub = param;
 	struct paging_signal_data sig_data;
 	struct bsc_subscr *bsub;
 	struct gsm_network *net;
 
-	OSMO_ASSERT(subscr && subscr->is_paging);
-	net = subscr->group->net;
+	OSMO_ASSERT(vsub && vsub->cs.is_paging);
+	net = vsub->vlr->user_ctx;
 
 	/*
 	 * Stop paging on all other BTS. E.g. if this is
@@ -95,18 +98,12 @@ static int subscr_paging_dispatch(unsigned int hooknum, unsigned int event,
 	 * and forget we wanted to page.
 	 */
 
-	/* TODO MSC split -- creating a BSC subscriber directly from MSC data
-	 * structures in RAM. At some point the MSC will send a message to the
-	 * BSC instead. */
-	bsub = bsc_subscr_find_or_create_by_imsi(net->bsc_subscribers,
-						 subscr->imsi);
-	bsub->tmsi = subscr->tmsi;
-	bsub->lac = subscr->lac;
+	bsub = vlr_subscr_to_bsc_sub(conn->network->bsc_subscribers, vsub);
 	paging_request_stop(&net->bts_list, NULL, bsub, NULL, NULL);
 	bsc_subscr_put(bsub);
 
 	/* Inform parts of the system we don't know */
-	sig_data.subscr = subscr;
+	sig_data.vsub	= vsub;
 	sig_data.bts	= conn ? conn->bts : NULL;
 	sig_data.conn	= conn;
 	sig_data.paging_result = event;
@@ -117,105 +114,52 @@ static int subscr_paging_dispatch(unsigned int hooknum, unsigned int event,
 		&sig_data
 	);
 
-	llist_for_each_entry_safe(request, tmp, &subscr->requests, entry) {
+	llist_for_each_entry_safe(request, tmp, &vsub->cs.requests, entry) {
 		llist_del(&request->entry);
 		request->cbfn(hooknum, event, msg, data, request->param);
 		talloc_free(request);
 	}
 
 	/* balanced with the moment we start paging */
-	subscr->is_paging = 0;
-	subscr_put(subscr);
+	vsub->cs.is_paging = false;
+	vlr_subscr_put(vsub);
 	return 0;
 }
 
-static int subscr_paging_sec_cb(unsigned int hooknum, unsigned int event,
-                                struct msgb *msg, void *data, void *param)
-{
-	int rc;
-
-	switch (event) {
-		case GSM_SECURITY_AUTH_FAILED:
-			/* Dispatch as paging failure */
-			rc = subscr_paging_dispatch(
-				GSM_HOOK_RR_PAGING, GSM_PAGING_EXPIRED,
-				msg, data, param);
-			break;
-
-		case GSM_SECURITY_NOAVAIL:
-		case GSM_SECURITY_SUCCEEDED:
-			/* Dispatch as paging failure */
-			rc = subscr_paging_dispatch(
-				GSM_HOOK_RR_PAGING, GSM_PAGING_SUCCEEDED,
-				msg, data, param);
-			break;
-
-		default:
-			rc = -EINVAL;
-	}
-
-	return rc;
-}
-
-static int subscr_paging_cb(unsigned int hooknum, unsigned int event,
-                            struct msgb *msg, void *data, void *param)
-{
-	struct gsm_subscriber_connection *conn = data;
-	struct gsm48_hdr *gh;
-	struct gsm48_pag_resp *pr;
-
-	/* Other cases mean problem, dispatch direclty */
-	if (event != GSM_PAGING_SUCCEEDED)
-		return subscr_paging_dispatch(hooknum, event, msg, data, param);
-
-	/* Get paging response */
-	gh = msgb_l3(msg);
-	pr = (struct gsm48_pag_resp *)gh->data;
-
-	/* We _really_ have a channel, secure it now ! */
-	return gsm48_secure_channel(conn, pr->key_seq, subscr_paging_sec_cb, param);
-}
-
-struct subscr_request *subscr_request_channel(struct gsm_subscriber *subscr,
-			int channel_type, gsm_cbfn *cbfn, void *param)
+struct subscr_request *subscr_request_channel(struct vlr_subscr *vsub,
+					      int channel_type,
+					      gsm_cbfn *cbfn, void *param)
 {
 	int rc;
 	struct subscr_request *request;
 	struct bsc_subscr *bsub;
-	struct gsm_network *net = subscr->group->net;
+	struct gsm_network *net = vsub->vlr->user_ctx;
 
 	/* Start paging.. we know it is async so we can do it before */
-	if (!subscr->is_paging) {
+	if (!vsub->cs.is_paging) {
 		LOGP(DMM, LOGL_DEBUG, "Subscriber %s not paged yet.\n",
-			subscr_name(subscr));
-		/* TODO MSC split -- creating a BSC subscriber directly from
-		 * MSC data structures in RAM. At some point the MSC will send
-		 * a message to the BSC instead. */
-		bsub = bsc_subscr_find_or_create_by_imsi(net->bsc_subscribers,
-							 subscr->imsi);
-		bsub->tmsi = subscr->tmsi;
-		bsub->lac = subscr->lac;
-		rc = paging_request(net, bsub, channel_type, subscr_paging_cb,
-				    subscr);
+		     vlr_subscr_name(vsub));
+		bsub = vlr_subscr_to_bsc_sub(net->bsc_subscribers, vsub);
+		rc = paging_request(net, bsub, channel_type, NULL, NULL);
 		bsc_subscr_put(bsub);
 		if (rc <= 0) {
 			LOGP(DMM, LOGL_ERROR, "Subscriber %s paging failed: %d\n",
-				subscr_name(subscr), rc);
+			     vlr_subscr_name(vsub), rc);
 			return NULL;
 		}
 		/* reduced on the first paging callback */
-		subscr_get(subscr);
-		subscr->is_paging = 1;
+		vlr_subscr_get(vsub);
+		vsub->cs.is_paging = true;
 	}
 
 	/* TODO: Stop paging in case of memory allocation failure */
-	request = talloc_zero(subscr, struct subscr_request);
+	request = talloc_zero(vsub, struct subscr_request);
 	if (!request)
 		return NULL;
 
 	request->cbfn = cbfn;
 	request->param = param;
-	llist_add_tail(&request->entry, &subscr->requests);
+	llist_add_tail(&request->entry, &vsub->cs.requests);
 	return request;
 }
 
@@ -225,196 +169,13 @@ void subscr_remove_request(struct subscr_request *request)
 	talloc_free(request);
 }
 
-struct gsm_subscriber *subscr_create_subscriber(struct gsm_subscriber_group *sgrp,
-						const char *imsi)
-{
-	struct gsm_subscriber *subscr = db_create_subscriber(imsi,
-							     sgrp->net->ext_min,
-							     sgrp->net->ext_max,
-							     sgrp->net->auto_assign_exten);
-	if (subscr)
-		subscr->group = sgrp;
-	return subscr;
-}
-
-struct gsm_subscriber *subscr_get_by_tmsi(struct gsm_subscriber_group *sgrp,
-					  uint32_t tmsi)
-{
-	char tmsi_string[14];
-	struct gsm_subscriber *subscr;
-
-	/* we might have a record in memory already */
-	llist_for_each_entry(subscr, subscr_bsc_active_subscribers(), entry) {
-		if (tmsi == subscr->tmsi)
-			return subscr_get(subscr);
-	}
-
-	sprintf(tmsi_string, "%u", tmsi);
-	return get_subscriber(sgrp, GSM_SUBSCRIBER_TMSI, tmsi_string);
-}
-
-struct gsm_subscriber *subscr_get_by_imsi(struct gsm_subscriber_group *sgrp,
-					  const char *imsi)
-{
-	struct gsm_subscriber *subscr;
-
-	llist_for_each_entry(subscr, subscr_bsc_active_subscribers(), entry) {
-		if (strcmp(subscr->imsi, imsi) == 0)
-			return subscr_get(subscr);
-	}
-
-	return get_subscriber(sgrp, GSM_SUBSCRIBER_IMSI, imsi);
-}
-
-struct gsm_subscriber *subscr_get_by_extension(struct gsm_subscriber_group *sgrp,
-					       const char *ext)
-{
-	struct gsm_subscriber *subscr;
-
-	llist_for_each_entry(subscr, subscr_bsc_active_subscribers(), entry) {
-		if (strcmp(subscr->extension, ext) == 0)
-			return subscr_get(subscr);
-	}
-
-	return get_subscriber(sgrp, GSM_SUBSCRIBER_EXTENSION, ext);
-}
-
-struct gsm_subscriber *subscr_get_by_id(struct gsm_subscriber_group *sgrp,
-					unsigned long long id)
-{
-	struct gsm_subscriber *subscr;
-	char buf[32];
-	sprintf(buf, "%llu", id);
-
-	llist_for_each_entry(subscr, subscr_bsc_active_subscribers(), entry) {
-		if (subscr->id == id)
-			return subscr_get(subscr);
-	}
-
-	return get_subscriber(sgrp, GSM_SUBSCRIBER_ID, buf);
-}
-
-int subscr_update_expire_lu(struct gsm_subscriber *s, struct gsm_bts *bts)
-{
-	int rc;
-
-	if (!s) {
-		LOGP(DMM, LOGL_ERROR, "LU Expiration but NULL subscriber\n");
-		return -1;
-	}
-	if (!bts) {
-		LOGP(DMM, LOGL_ERROR, "%s: LU Expiration but NULL bts\n",
-		     subscr_name(s));
-		return -1;
-	}
-
-	/* Table 10.5.33: The T3212 timeout value field is coded as the
-	 * binary representation of the timeout value for
-	 * periodic updating in decihours. Mark the subscriber as
-	 * inactive if it missed two consecutive location updates.
-	 * Timeout is twice the t3212 value plus one minute */
-
-	/* Is expiration handling enabled? */
-	if (bts->si_common.chan_desc.t3212 == 0)
-		s->expire_lu = GSM_SUBSCRIBER_NO_EXPIRATION;
-	else
-		s->expire_lu = time(NULL) +
-			(bts->si_common.chan_desc.t3212 * 60 * 6 * 2) + 60;
-
-	rc = db_sync_subscriber(s);
-	db_subscriber_update(s);
-	return rc;
-}
-
-int subscr_update(struct gsm_subscriber *s, struct gsm_bts *bts, int reason)
-{
-	int rc;
-
-	/* FIXME: Migrate pending requests from one BSC to another */
-	switch (reason) {
-	case GSM_SUBSCRIBER_UPDATE_ATTACHED:
-		s->group = bts->network->subscr_group;
-		/* Indicate "attached to LAC" */
-		s->lac = bts->location_area_code;
-
-		LOGP(DMM, LOGL_INFO, "Subscriber %s ATTACHED LAC=%u\n",
-			subscr_name(s), s->lac);
-
-		/*
-		 * The below will set a new expire_lu but as a side-effect
-		 * the new lac will be saved in the database.
-		 */
-		rc = subscr_update_expire_lu(s, bts);
-		osmo_signal_dispatch(SS_SUBSCR, S_SUBSCR_ATTACHED, s);
-		break;
-	case GSM_SUBSCRIBER_UPDATE_DETACHED:
-		/* Only detach if we are currently in this area */
-		if (bts->location_area_code == s->lac)
-			s->lac = GSM_LAC_RESERVED_DETACHED;
-		LOGP(DMM, LOGL_INFO, "Subscriber %s DETACHED\n", subscr_name(s));
-		rc = db_sync_subscriber(s);
-		db_subscriber_update(s);
-		osmo_signal_dispatch(SS_SUBSCR, S_SUBSCR_DETACHED, s);
-		break;
-	default:
-		fprintf(stderr, "subscr_update with unknown reason: %d\n",
-			reason);
-		rc = db_sync_subscriber(s);
-		db_subscriber_update(s);
-		break;
-	};
-
-	return rc;
-}
-
-void subscr_update_from_db(struct gsm_subscriber *sub)
-{
-	db_subscriber_update(sub);
-}
-
-static void subscr_expire_callback(void *data, long long unsigned int id)
-{
-	struct gsm_network *net = data;
-	struct gsm_subscriber *s = subscr_get_by_id(net->subscr_group, id);
-	struct gsm_subscriber_connection *conn = connection_for_subscr(s);
-
-	/*
-	 * The subscriber is active and the phone stopped the timer. As
-	 * we don't want to periodically update the database for active
-	 * subscribers we will just do it when the subscriber was selected
-	 * for expiration. This way on the next around another subscriber
-	 * will be selected.
-	 */
-	if (conn && conn->expire_timer_stopped) {
-		LOGP(DMM, LOGL_DEBUG, "Not expiring subscriber %s (ID %llu)\n",
-			subscr_name(s), id);
-		subscr_update_expire_lu(s, conn->bts);
-		subscr_put(s);
-		return;
-	}
-
-
-	LOGP(DMM, LOGL_NOTICE, "Expiring inactive subscriber %s (ID %llu)\n",
-			subscr_name(s), id);
-	s->lac = GSM_LAC_RESERVED_DETACHED;
-	db_sync_subscriber(s);
-
-	subscr_put(s);
-}
-
-void subscr_expire(struct gsm_subscriber_group *sgrp)
-{
-	db_subscriber_expire(sgrp->net, subscr_expire_callback);
-}
-
-struct gsm_subscriber_connection *connection_for_subscr(struct gsm_subscriber *subscr)
+struct gsm_subscriber_connection *connection_for_subscr(struct vlr_subscr *vsub)
 {
-	/* FIXME: replace this with a backpointer in gsm_subscriber? */
-	struct gsm_network *net = subscr->group->net;
+	struct gsm_network *net = vsub->vlr->user_ctx;
 	struct gsm_subscriber_connection *conn;
 
 	llist_for_each_entry(conn, &net->subscr_conns, entry) {
-		if (conn->subscr == subscr)
+		if (conn->vsub == vsub)
 			return conn;
 	}