ASCI: Send release on VGCS/VBS channel via unit data

Channel release is sent to MS that is in dedicated mode on the main
DCCH. Additionally it is sent as unit data on a VGCS/VBS to notify all
listeners that the channel has been released. All listeners return to
IDLE mode.

Change-Id: Ib777fe98c8ce2342082d88d227b796167d92cfe1
Related: OS#4852

3 files changed, 25 insertions, 7 deletions

diff --git a/include/osmocom/bsc/gsm_04_08_rr.h b/include/osmocom/bsc/gsm_04_08_rr.h
index 3106e7739..9a9956b95 100644
--- a/include/osmocom/bsc/gsm_04_08_rr.h
+++ b/include/osmocom/bsc/gsm_04_08_rr.h
@@ -18,7 +18,7 @@ struct gsm_subscriber_connection;
 void gsm_net_update_ctype(struct gsm_network *network);
 enum gsm_chan_t get_ctype_by_chreq(struct gsm_network *network, uint8_t ra);
 int get_reason_by_chreq(uint8_t ra, int neci);
-int gsm48_send_rr_release(struct gsm_lchan *lchan);
+int gsm48_send_rr_release(struct gsm_lchan *lchan, bool ui);
 int send_siemens_mrpci(struct gsm_lchan *lchan,
 		       uint8_t *classmark2_lv);
 int gsm48_send_rr_classmark_enquiry(struct gsm_lchan *lchan);
diff --git a/src/osmo-bsc/gsm_04_08_rr.c b/src/osmo-bsc/gsm_04_08_rr.c
index 78a4f4572..60ccb5ac9 100644
--- a/src/osmo-bsc/gsm_04_08_rr.c
+++ b/src/osmo-bsc/gsm_04_08_rr.c
@@ -308,12 +308,15 @@ static int generate_cell_sel_ind_after_rel(uint8_t *out, unsigned int out_len, c
 	}
 }
 
+#define REPEAT_RR_RELEASE_UI	3
+
 /* 7.1.7 and 9.1.7: RR CHANnel RELease */
-int gsm48_send_rr_release(struct gsm_lchan *lchan)
+int gsm48_send_rr_release(struct gsm_lchan *lchan, bool ui)
 {
-	struct msgb *msg = gsm48_msgb_alloc_name("GSM 04.08 RR REL");
+	struct msgb *msg = gsm48_msgb_alloc_name("GSM 04.08 RR REL"), *msgc;
 	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh));
 	uint8_t *cause;
+	int n;
 
 	msg->lchan = lchan;
 	gh->proto_discr = GSM48_PDISC_RR;
@@ -338,8 +341,17 @@ int gsm48_send_rr_release(struct gsm_lchan *lchan)
 	       gsm_lchan_name(lchan),  lchan->release.rr_cause,
 	       rr_cause_name(lchan->release.rr_cause));
 
-	/* Send actual release request to MS */
-	return gsm48_sendmsg(msg);
+	/* Send actual release request to MS (dedicated channel) */
+	if (!ui)
+		return gsm48_sendmsg(msg);
+
+	/* Send actual release request to MS (VGCS channel) */
+	for (n = 1; n < REPEAT_RR_RELEASE_UI; n++) {
+		msgc = msgb_copy(msg, "CHAN RELEASE copy");
+		msgc->lchan = lchan;
+		gsm48_sendmsg_unit(msgc);
+	}
+	return gsm48_sendmsg_unit(msg);
 }
 
 int send_siemens_mrpci(struct gsm_lchan *lchan,
diff --git a/src/osmo-bsc/lchan_fsm.c b/src/osmo-bsc/lchan_fsm.c
index 70fb81161..26c188236 100644
--- a/src/osmo-bsc/lchan_fsm.c
+++ b/src/osmo-bsc/lchan_fsm.c
@@ -1421,8 +1421,14 @@ static bool should_sacch_deact(struct gsm_lchan *lchan)
 
 static void lchan_do_release(struct gsm_lchan *lchan)
 {
-	if (lchan->release.do_rr_release && lchan->sapis[0] != LCHAN_SAPI_UNUSED)
-		gsm48_send_rr_release(lchan);
+	if (lchan->release.do_rr_release) {
+		/* To main DCCH in dedicated and group transmit mode */
+		if (lchan->sapis[0] != LCHAN_SAPI_UNUSED)
+			gsm48_send_rr_release(lchan, false);
+		/* As UI to all listeners in group receive mode */
+		if (lchan_is_asci(lchan))
+			gsm48_send_rr_release(lchan, true);
+	}
 
 	if (lchan->fi_rtp)
 		osmo_fsm_inst_dispatch(lchan->fi_rtp, LCHAN_RTP_EV_RELEASE, 0);