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-rw-r--r--openbsc/src/libmsc/iucs.c191
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diff --git a/openbsc/src/libmsc/iucs.c b/openbsc/src/libmsc/iucs.c
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+++ b/openbsc/src/libmsc/iucs.c
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+/* Code to manage MSC subscriber connections over IuCS interface */
+
+/*
+ * (C) 2016,2017 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ *
+ * Author: Neels Hofmeyr <nhofmeyr@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <inttypes.h>
+
+#include <osmocom/core/logging.h>
+#include <openbsc/debug.h>
+
+#include <openbsc/gsm_data.h>
+#include <openbsc/iu.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/osmo_msc.h>
+#include <openbsc/vlr.h>
+
+/* For A-interface see libbsc/bsc_api.c subscr_con_allocate() */
+static struct gsm_subscriber_connection *subscr_conn_allocate_iu(struct gsm_network *network,
+ struct ue_conn_ctx *ue,
+ uint16_t lac)
+{
+ struct gsm_subscriber_connection *conn;
+
+ DEBUGP(DIUCS, "Allocating IuCS subscriber conn: lac %d, link_id %p, conn_id %" PRIx32 "\n",
+ lac, ue->link, ue->conn_id);
+
+ conn = talloc_zero(network, struct gsm_subscriber_connection);
+ if (!conn)
+ return NULL;
+
+ conn->network = network;
+ conn->via_ran = RAN_UTRAN_IU;
+ conn->iu.ue_ctx = ue;
+ conn->iu.ue_ctx->rab_assign_addr_enc = network->iu.rab_assign_addr_enc;
+ conn->lac = lac;
+
+ llist_add_tail(&conn->entry, &network->subscr_conns);
+ return conn;
+}
+
+static int same_ue_conn(struct ue_conn_ctx *a, struct ue_conn_ctx *b)
+{
+ if (a == b)
+ return 1;
+ return (a->link == b->link)
+ && (a->conn_id == b->conn_id);
+}
+
+static inline void log_subscribers(struct gsm_network *network)
+{
+ if (!log_check_level(DIUCS, LOGL_DEBUG))
+ return;
+
+ struct gsm_subscriber_connection *conn;
+ int i = 0;
+ llist_for_each_entry(conn, &network->subscr_conns, entry) {
+ DEBUGP(DIUCS, "%3d: %s", i, vlr_subscr_name(conn->vsub));
+ switch (conn->via_ran) {
+ case RAN_UTRAN_IU:
+ DEBUGPC(DIUCS, " Iu");
+ if (conn->iu.ue_ctx) {
+ DEBUGPC(DIUCS, " link %p, conn_id %d",
+ conn->iu.ue_ctx->link,
+ conn->iu.ue_ctx->conn_id
+ );
+ }
+ break;
+ case RAN_GERAN_A:
+ DEBUGPC(DIUCS, " A");
+ /* TODO log A-interface connection details */
+ break;
+ case RAN_UNKNOWN:
+ DEBUGPC(DIUCS, " ?");
+ break;
+ default:
+ DEBUGPC(DIUCS, " invalid");
+ break;
+ }
+ DEBUGPC(DIUCS, "\n");
+ i++;
+ }
+ DEBUGP(DIUCS, "subscribers registered: %d\n", i);
+}
+
+/* Return an existing IuCS subscriber connection record for the given link and
+ * connection IDs, or return NULL if not found. */
+struct gsm_subscriber_connection *subscr_conn_lookup_iu(
+ struct gsm_network *network,
+ struct ue_conn_ctx *ue)
+{
+ struct gsm_subscriber_connection *conn;
+
+ DEBUGP(DIUCS, "Looking for IuCS subscriber: link_id %p, conn_id %" PRIx32 "\n",
+ ue->link, ue->conn_id);
+ log_subscribers(network);
+
+ llist_for_each_entry(conn, &network->subscr_conns, entry) {
+ if (conn->via_ran != RAN_UTRAN_IU)
+ continue;
+ if (!same_ue_conn(conn->iu.ue_ctx, ue))
+ continue;
+ DEBUGP(DIUCS, "Found IuCS subscriber for link_id %p, conn_id %" PRIx32 "\n",
+ ue->link, ue->conn_id);
+ return conn;
+ }
+ DEBUGP(DIUCS, "No IuCS subscriber found for link_id %p, conn_id %" PRIx32 "\n",
+ ue->link, ue->conn_id);
+ return NULL;
+}
+
+/* Receive MM/CC/... message from IuCS (SCCP user SAP).
+ * msg->dst must reference a struct ue_conn_ctx, which identifies the peer that
+ * sent the msg.
+ *
+ * For A-interface see libbsc/bsc_api.c gsm0408_rcvmsg(). */
+int gsm0408_rcvmsg_iucs(struct gsm_network *network, struct msgb *msg,
+ uint16_t *lac)
+{
+ int rc;
+ struct ue_conn_ctx *ue_ctx;
+ struct gsm_subscriber_connection *conn;
+
+ ue_ctx = (struct ue_conn_ctx*)msg->dst;
+
+ /* TODO: are there message types that could allow us to skip this
+ * search? */
+ conn = subscr_conn_lookup_iu(network, ue_ctx);
+
+ if (conn && lac && (conn->lac != *lac)) {
+ LOGP(DIUCS, LOGL_ERROR, "IuCS subscriber has changed LAC"
+ " within the same connection, discarding connection:"
+ " %s from LAC %d to %d\n",
+ vlr_subscr_name(conn->vsub), conn->lac, *lac);
+ /* Deallocate conn with previous LAC */
+ msc_subscr_conn_close(conn, GSM_CAUSE_INV_MAND_INFO);
+ /* At this point we could be tolerant and allocate a new
+ * connection, but changing the LAC within the same connection
+ * is shifty. Rather cancel everything. */
+ return -1;
+ }
+
+ if (conn) {
+ /* Make sure we don't receive RR over IuCS; otherwise all
+ * messages handled by gsm0408_dispatch() are of interest (CC,
+ * MM, SMS, NS_SS, maybe even MM_GPRS and SM_GPRS). */
+ struct gsm48_hdr *gh = msgb_l3(msg);
+ uint8_t pdisc = gh->proto_discr & 0x0f;
+ OSMO_ASSERT(pdisc != GSM48_PDISC_RR);
+
+ msc_dtap(conn, ue_ctx->conn_id, msg);
+ rc = 0;
+ } else {
+ /* allocate a new connection */
+
+ if (!lac) {
+ LOGP(DIUCS, LOGL_ERROR, "New IuCS subscriber"
+ " but no LAC available. Expecting an InitialUE"
+ " message containing a LAI IE."
+ " Dropping connection.\n");
+ return -1;
+ }
+
+ conn = subscr_conn_allocate_iu(network, ue_ctx, *lac);
+ if (!conn)
+ abort();
+
+ /* ownership of conn hereby goes to the MSC: */
+ rc = msc_compl_l3(conn, msg, 0);
+ }
+
+ return rc;
+}