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, 68 insertions, 1 deletions

diff --git a/include/openbsc/osmo_msc.h b/include/openbsc/osmo_msc.h
index beb3f5e4c..0642c9109 100644
--- a/include/openbsc/osmo_msc.h
+++ b/include/openbsc/osmo_msc.h
@@ -3,9 +3,76 @@
 #ifndef OSMO_MSC_H
 #define OSMO_MSC_H
 
+#include <osmocom/core/fsm.h>
+#include <osmocom/gsm/gsup.h>
+
+#include <openbsc/gsm_data.h>
+
 #include "bsc_api.h"
 
+#define MSC_HLR_REMOTE_IP_DEFAULT "127.0.0.1"
+#define MSC_HLR_REMOTE_PORT_DEFAULT OSMO_GSUP_PORT
+
+enum subscr_conn_fsm_event {
+	/* Mark 0 as invalid to catch uninitialized vars */
+	SUBSCR_CONN_E_INVALID = 0,
+	/* Timeout on connection establishment starts */
+	SUBSCR_CONN_E_START,
+	/* LU or Process Access FSM has determined that this conn is good */
+	SUBSCR_CONN_E_ACCEPTED,
+	/* received first reply from MS in "real" CC, SMS, USSD communication */
+	SUBSCR_CONN_E_COMMUNICATING,
+	/* Some async action has completed, check again whether all is done */
+	SUBSCR_CONN_E_BUMP,
+	/* MS/BTS/BSC originated close request */
+	SUBSCR_CONN_E_MO_CLOSE,
+	/* MSC originated close request, e.g. failed authentication */
+	SUBSCR_CONN_E_CN_CLOSE,
+};
+
+enum subscr_conn_fsm_state {
+	SUBSCR_CONN_S_INIT,
+	SUBSCR_CONN_S_NEW,
+	SUBSCR_CONN_S_ACCEPTED,
+	SUBSCR_CONN_S_COMMUNICATING,
+	SUBSCR_CONN_S_RELEASED,
+};
+
+enum subscr_conn_from {
+	SUBSCR_CONN_FROM_INVALID,
+	SUBSCR_CONN_FROM_LU,
+	SUBSCR_CONN_FROM_CM_SERVICE_REQ,
+	SUBSCR_CONN_FROM_PAGING_RESP,
+};
+
+extern const struct value_string subscr_conn_from_names[];
+static inline const char *subscr_conn_from_name(enum subscr_conn_from val)
+{
+	return get_value_string(subscr_conn_from_names, val);
+}
+
+
 struct bsc_api *msc_bsc_api();
-void msc_release_connection(struct gsm_subscriber_connection *conn);
+
+int msc_create_conn_fsm(struct gsm_subscriber_connection *conn, const char *id);
+
+int msc_vlr_alloc(struct gsm_network *net);
+int msc_vlr_start(struct gsm_network *net);
+
+void msc_subscr_conn_init(void);
+bool msc_subscr_conn_is_accepted(struct gsm_subscriber_connection *conn);
+void msc_subscr_conn_communicating(struct gsm_subscriber_connection *conn);
+void msc_subscr_conn_close(struct gsm_subscriber_connection *conn,
+			   uint32_t cause);
+
+#define msc_subscr_conn_get(conn) \
+	_msc_subscr_conn_get(conn, __BASE_FILE__, __LINE__)
+#define msc_subscr_conn_put(conn) \
+	_msc_subscr_conn_put(conn, __BASE_FILE__, __LINE__)
+struct gsm_subscriber_connection *
+_msc_subscr_conn_get(struct gsm_subscriber_connection *conn,
+		     const char *file, int line);
+void _msc_subscr_conn_put(struct gsm_subscriber_connection *conn,
+			  const char *file, int line);
 
 #endif