abis_rsl: parse cm3 and indicate ACCH repetition cap to BTS

In order to activate FACCH/SACCH repetition on the BTS, the classmark 3
IE in the CLASSMARK CHANGE message must be parsed and depending on the
Repeated ACCH Capability bit the RSL_IE_OSMO_REP_ACCH_CAP is added to
the RSL CHAN ACT und RSL CHAN MODE MODIFY. Since
RSL_IE_OSMO_REP_ACCH_CAP is a propritary IE, it may only be added for
BTS type osmo-bts.

Change-Id: I39ae439d05562b35b2e47774dc92f8789fea1a57
Related: OS#4796 SYS#5114

3 files changed, 43 insertions, 0 deletions

diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index ed40e360f..a5b5a50f7 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -322,6 +322,9 @@ struct gsm_subscriber_connection {
 			enum subscr_sccp_state state;
 		} lb;
 	} lcs;
+
+	struct gsm48_classmark3 cm3;
+	bool cm3_valid;
 };
 
 
diff --git a/src/osmo-bsc/abis_rsl.c b/src/osmo-bsc/abis_rsl.c
index 858c683e1..f8ea5a5d7 100644
--- a/src/osmo-bsc/abis_rsl.c
+++ b/src/osmo-bsc/abis_rsl.c
@@ -457,6 +457,35 @@ static void mr_config_for_bts(struct gsm_lchan *lchan, struct msgb *msg)
 		     lchan->mr_bts_lv + 1);
 }
 
+/* indicate FACCH/SACCH Repetition to be performed by BTS,
+ * see also: 3GPP TS 44.006, section 10 and 11 */
+static void rep_acch_cap_for_bts(struct gsm_lchan *lchan,
+				 struct msgb *msg)
+{
+	struct abis_rsl_osmo_rep_acch_cap *cap;
+	struct gsm_bts *bts = lchan->ts->trx->bts;
+
+	/* The RSL_IE_OSMO_REP_ACCH_CAP IE is a proprietary IE, that can only
+	 * be used with osmo-bts type BTSs */
+	if (!(bts->model->type == GSM_BTS_TYPE_OSMOBTS
+	      && osmo_bts_has_feature(&bts->features, BTS_FEAT_ACCH_REP)))
+		return;
+
+	cap = (struct abis_rsl_osmo_rep_acch_cap*) msg->tail;
+	msgb_tlv_put(msg, RSL_IE_OSMO_REP_ACCH_CAP, sizeof(*cap),
+		     (uint8_t*) &bts->repeated_acch_policy);
+
+	if (!(lchan->conn && lchan->conn->cm3_valid
+	      && lchan->conn->cm3.repeated_acch_capability)) {
+		/* MS supports only FACCH repetition for command frames, so
+		 * we mask out all other features, even when they are enabled
+		 * on this BTS. */
+		cap->dl_facch_all = 0;
+		cap->dl_sacch = 0;
+		cap->ul_sacch = 0;
+	}
+}
+
 /* Chapter 8.4.1 */
 int rsl_tx_chan_activ(struct gsm_lchan *lchan, uint8_t act_type, uint8_t ho_ref)
 {
@@ -552,6 +581,7 @@ int rsl_tx_chan_activ(struct gsm_lchan *lchan, uint8_t act_type, uint8_t ho_ref)
 	   better skip sending it unless we know for sure what each expects. */
 
 	mr_config_for_bts(lchan, msg);
+	rep_acch_cap_for_bts(lchan, msg);
 
 	msg->dst = trx->rsl_link;
 
@@ -590,6 +620,7 @@ int rsl_chan_mode_modify_req(struct gsm_lchan *lchan)
 	}
 
 	mr_config_for_bts(lchan, msg);
+        rep_acch_cap_for_bts(lchan, msg);
 
 	msg->dst = lchan->ts->trx->rsl_link;
 
diff --git a/src/osmo-bsc/gsm_08_08.c b/src/osmo-bsc/gsm_08_08.c
index 2c51c958a..9c5cf2faf 100644
--- a/src/osmo-bsc/gsm_08_08.c
+++ b/src/osmo-bsc/gsm_08_08.c
@@ -34,6 +34,7 @@
 #include <osmocom/bsc/lcs_loc_req.h>
 
 #include <osmocom/gsm/protocol/gsm_08_08.h>
+#include <osmocom/gsm/protocol/gsm_04_08.h>
 #include <osmocom/gsm/gsm0808.h>
 #include <osmocom/gsm/mncc.h>
 #include <osmocom/gsm/gsm48.h>
@@ -602,6 +603,14 @@ void bsc_cm_update(struct gsm_subscriber_connection *conn,
 	}
 	conn_update_ms_power_class(conn, rc8);
 
+        rc = gsm48_decode_classmark3(&conn->cm3, cm3, cm3_len);
+	if (rc < 0) {
+		LOGP(DMSC, LOGL_NOTICE, "Unable to decode classmark3 during CM Update.\n");
+		memset(&conn->cm3, 0, sizeof(conn->cm3));
+		conn->cm3_valid = false;
+	} else
+		conn->cm3_valid = true;
+
 	if (!msc_connected(conn))
 		return;