From 18fa70aa3afbcb997c3ac1c1fe0e3808958533cb Mon Sep 17 00:00:00 2001
From: Holger Hans Peter Freyther <zecke@selfish.org>
Date: Wed, 8 Jun 2011 19:25:38 +0200
Subject: bsc: Look for CM Service Requests with emergency cause

Look for emergency calls and send them to a MSC that can
handle them properly.
---
 openbsc/include/openbsc/osmo_msc_data.h |  1 +
 openbsc/src/osmo-bsc/osmo_bsc_filter.c  | 25 +++++++++++++++++++++++--
 openbsc/src/osmo-bsc/osmo_bsc_msc.c     |  1 +
 3 files changed, 25 insertions(+), 2 deletions(-)

(limited to 'openbsc')

diff --git a/openbsc/include/openbsc/osmo_msc_data.h b/openbsc/include/openbsc/osmo_msc_data.h
index 9edf880cf..0bda66225 100644
--- a/openbsc/include/openbsc/osmo_msc_data.h
+++ b/openbsc/include/openbsc/osmo_msc_data.h
@@ -46,6 +46,7 @@ struct osmo_msc_data {
 	/* Back pointer */
 	struct gsm_network *network;
 
+	int allow_emerg;
 	int type;
 
 	/* Connection data */
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_filter.c b/openbsc/src/osmo-bsc/osmo_bsc_filter.c
index 3bc2dfd7f..fa7f2d928 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_filter.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_filter.c
@@ -106,6 +106,21 @@ static int handle_page_resp(struct gsm_subscriber_connection *conn, struct msgb
 	subscr_put(subscr);
 	return 0;
 }
+
+static int is_cm_service_for_emerg(struct msgb *msg)
+{
+	struct gsm48_service_request *cm;
+	struct gsm48_hdr *gh = msgb_l3(msg);
+
+	if (msgb_l3len(msg) < sizeof(*gh) + sizeof(*cm)) {
+		LOGP(DMSC, LOGL_ERROR, "CM ServiceRequest does not fit.\n");
+		return 0;
+	}
+
+	cm = (struct gsm48_service_request *) &gh->data[0];
+	return cm->cm_service_type == GSM48_CMSERV_EMERGENCY;
+}
+
 struct osmo_msc_data *bsc_find_msc(struct gsm_subscriber_connection *conn,
 				   struct msgb *msg)
 {
@@ -115,6 +130,7 @@ struct osmo_msc_data *bsc_find_msc(struct gsm_subscriber_connection *conn,
 	struct osmo_bsc_data *bsc;
 	struct osmo_msc_data *msc, *pag_msc;
 	struct gsm_subscriber *subscr;
+	int is_emerg = 0;
 
 	bsc = conn->bts->network->bsc_data;
 
@@ -135,14 +151,19 @@ struct osmo_msc_data *bsc_find_msc(struct gsm_subscriber_connection *conn,
 	 */
 	if (pdisc == GSM48_PDISC_RR && mtype == GSM48_MT_RR_PAG_RESP)
 		goto paging;
-	else
+	else if (pdisc == GSM48_PDISC_MM && mtype == GSM48_MT_MM_CM_SERV_REQ) {
+		is_emerg = is_cm_service_for_emerg(msg);
+		goto round_robin;
+	} else
 		goto round_robin;
 
 round_robin:
 	llist_for_each_entry(msc, &bsc->mscs, entry) {
 		if (!msc->msc_con->is_authenticated)
 			continue;
-		if (msc->type != MSC_CON_TYPE_NORMAL)
+		if (!is_emerg && msc->type != MSC_CON_TYPE_NORMAL)
+			continue;
+		if (is_emerg && !msc->allow_emerg)
 			continue;
 
 		/* force round robin by moving it to the end */
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_msc.c b/openbsc/src/osmo-bsc/osmo_bsc_msc.c
index 617a59aee..55532dbd4 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_msc.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_msc.c
@@ -492,6 +492,7 @@ struct osmo_msc_data *osmo_msc_data_alloc(struct gsm_network *net, int nr)
 	msc_data->rtp_base = 4000;
 
 	msc_data->nr = nr;
+	msc_data->allow_emerg = 1;
 
 	return msc_data;
 }
-- 
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