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 trial-and-error development collapsed in one patch.
This may be split in smaller commits if reviewers prefer that. If we can keep
it as one, we have saved ourselves the additional separation work.

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.

Remove/Disable VTY and CTRL commands to create subscribers, which is now a task
of the OsmoHLR. Adjust the python tests accordingly.

Remove VTY cmd subscriber-keep-in-ram.

Use OSMO_GSUP_PORT = 4222 instead of 2222. See
I4222e21686c823985be8ff1f16b1182be8ad6175.

So far use the LAC from conn->bts, will be replaced by conn->lac in
Id3705236350d5f69e447046b0a764bbabc3d493c.

Related: OS#1592 OS#1974
Change-Id: I639544a6cdda77a3aafc4e3446a55393f60e4050

1 files changed, 66 insertions, 15 deletions

diff --git a/src/libmsc/transaction.c b/src/libmsc/transaction.c
index dba4bed17..d157f5469 100644
--- a/src/libmsc/transaction.c
+++ b/src/libmsc/transaction.c
@@ -23,25 +23,31 @@
 #include <openbsc/mncc.h>
 #include <openbsc/debug.h>
 #include <osmocom/core/talloc.h>
-#include <openbsc/gsm_subscriber.h>
 #include <openbsc/gsm_04_08.h>
 #include <openbsc/mncc.h>
 #include <openbsc/paging.h>
 #include <openbsc/osmo_msc.h>
+#include <openbsc/vlr.h>
 
 void *tall_trans_ctx;
 
 void _gsm48_cc_trans_free(struct gsm_trans *trans);
 
+/*! Find a transaction in connection for given protocol + transaction ID
+ * \param[in] conn Connection in whihc we want to find transaction
+ * \param[in] proto Protocol of transaction
+ * \param[in] trans_id Transaction ID of transaction
+ * \returns Matching transaction, if any
+ */
 struct gsm_trans *trans_find_by_id(struct gsm_subscriber_connection *conn,
 				   uint8_t proto, uint8_t trans_id)
 {
 	struct gsm_trans *trans;
 	struct gsm_network *net = conn->network;
-	struct gsm_subscriber *subscr = conn->subscr;
+	struct vlr_subscr *vsub = conn->vsub;
 
 	llist_for_each_entry(trans, &net->trans_list, entry) {
-		if (trans->subscr == subscr &&
+		if (trans->vsub == vsub &&
 		    trans->protocol == proto &&
 		    trans->transaction_id == trans_id)
 			return trans;
@@ -49,6 +55,11 @@ struct gsm_trans *trans_find_by_id(struct gsm_subscriber_connection *conn,
 	return NULL;
 }
 
+/*! Find a transaction by call reference
+ * \param[in] net Network in which we should search
+ * \param[in] callref Call Reference of transaction
+ * \returns Matching transaction, if any
+ */
 struct gsm_trans *trans_find_by_callref(struct gsm_network *net,
 					uint32_t callref)
 {
@@ -61,21 +72,27 @@ struct gsm_trans *trans_find_by_callref(struct gsm_network *net,
 	return NULL;
 }
 
+/*! Allocate a new transaction and add it to network list
+ *  \param[in] net Netwokr in which we allocate transaction
+ *  \param[in] subscr Subscriber for which we allocate transaction
+ *  \param[in] protocol Protocol (CC/SMS/...)
+ *  \param[in] callref Call Reference
+ *  \returns Transaction
+ */
 struct gsm_trans *trans_alloc(struct gsm_network *net,
-			      struct gsm_subscriber *subscr,
+			      struct vlr_subscr *vsub,
 			      uint8_t protocol, uint8_t trans_id,
 			      uint32_t callref)
 {
 	struct gsm_trans *trans;
 
-	DEBUGP(DCC, "subscr=%p, net=%p\n", subscr, net);
+	DEBUGP(DCC, "subscr=%p, net=%p\n", vsub, net);
 
 	trans = talloc_zero(tall_trans_ctx, struct gsm_trans);
 	if (!trans)
 		return NULL;
 
-	trans->subscr = subscr;
-	subscr_get(trans->subscr);
+	trans->vsub = vlr_subscr_get(vsub);
 
 	trans->protocol = protocol;
 	trans->transaction_id = trans_id;
@@ -87,6 +104,9 @@ struct gsm_trans *trans_alloc(struct gsm_network *net,
 	return trans;
 }
 
+/*! Release a transaction
+ * \param[in] trans Transaction to be released
+ */
 void trans_free(struct gsm_trans *trans)
 {
 	switch (trans->protocol) {
@@ -103,23 +123,28 @@ void trans_free(struct gsm_trans *trans)
 		trans->paging_request = NULL;
 	}
 
-	if (trans->subscr) {
-		subscr_put(trans->subscr);
-		trans->subscr = NULL;
+	if (trans->vsub) {
+		vlr_subscr_put(trans->vsub);
+		trans->vsub = NULL;
 	}
 
 	llist_del(&trans->entry);
 
 	if (trans->conn)
-		msc_release_connection(trans->conn);
+		msc_subscr_conn_put(trans->conn);
 
 	trans->conn = NULL;
 	talloc_free(trans);
 }
 
-/* allocate an unused transaction ID for the given subscriber
- * in the given protocol using the ti_flag specified */
-int trans_assign_trans_id(struct gsm_network *net, struct gsm_subscriber *subscr,
+/*! allocate an unused transaction ID for the given subscriber
+ * in the given protocol using the ti_flag specified
+ * \param[in] net GSM network
+ * \param[in] subscr Subscriber for which to find ID
+ * \param[in] protocol Protocol for whihc to find ID
+ * \param[in] ti_flag FIXME
+ */
+int trans_assign_trans_id(struct gsm_network *net, struct vlr_subscr *vsub,
 			  uint8_t protocol, uint8_t ti_flag)
 {
 	struct gsm_trans *trans;
@@ -131,7 +156,7 @@ int trans_assign_trans_id(struct gsm_network *net, struct gsm_subscriber *subscr
 
 	/* generate bitmask of already-used TIDs for this (subscr,proto) */
 	llist_for_each_entry(trans, &net->trans_list, entry) {
-		if (trans->subscr != subscr ||
+		if (trans->vsub != vsub ||
 		    trans->protocol != protocol ||
 		    trans->transaction_id == 0xff)
 			continue;
@@ -151,6 +176,10 @@ int trans_assign_trans_id(struct gsm_network *net, struct gsm_subscriber *subscr
 	return -1;
 }
 
+/*! Check if we have any transaction for given connection
+ * \param[in] conn Connection to check
+ * \returns 1 in case there is a transaction, 0 otherwise
+ */
 int trans_has_conn(const struct gsm_subscriber_connection *conn)
 {
 	struct gsm_trans *trans;
@@ -161,3 +190,25 @@ int trans_has_conn(const struct gsm_subscriber_connection *conn)
 
 	return 0;
 }
+
+/*! Free all transactions associated with a connection, presumably when the
+ * conn is being closed. The transaction code will inform the CC or SMS
+ * facilities, which will then send the necessary release indications.
+ * \param[in] conn Connection that is going to be closed.
+ */
+void trans_conn_closed(struct gsm_subscriber_connection *conn)
+{
+	struct gsm_trans *trans;
+
+	/* As part of the CC REL_IND the remote leg might be released and this
+	 * will trigger another call to trans_free. This is something the llist
+	 * macro can not handle and we need to re-iterate the list every time.
+	 */
+restart:
+	llist_for_each_entry(trans, &conn->network->trans_list, entry) {
+		if (trans->conn == conn) {
+			trans_free(trans);
+			goto restart;
+		}
+	}
+}