layer23/common: move signal loss criteria to L23SAP

Change-Id: Ib70bf9104cf3b5489413dd90819fd4955ec16f95

2 files changed, 83 insertions, 67 deletions

diff --git a/src/host/layer23/src/common/l1ctl.c b/src/host/layer23/src/common/l1ctl.c
index 0dd6bd55..d48e2845 100644
--- a/src/host/layer23/src/common/l1ctl.c
+++ b/src/host/layer23/src/common/l1ctl.c
@@ -122,8 +122,6 @@ static int rx_data_ind(struct osmocom_ms *ms, struct msgb *msg)
 {
 	struct l1ctl_info_dl *dl;
 	struct l1ctl_data_ind *ccch;
-	struct rx_meas_stat *meas = &ms->meas;
-	uint8_t chan_type, chan_ts, chan_ss;
 	struct gsm_time tm;
 
 	if (msgb_l1len(msg) < sizeof(*dl)) {
@@ -138,76 +136,11 @@ static int rx_data_ind(struct osmocom_ms *ms, struct msgb *msg)
 	ccch = (struct l1ctl_data_ind *) msg->l2h;
 
 	gsm_fn2gsmtime(&tm, ntohl(dl->frame_nr));
-	rsl_dec_chan_nr(dl->chan_nr, &chan_type, &chan_ss, &chan_ts);
 	DEBUGP(DL1C, "%s (%.4u/%.2u/%.2u) %d dBm: %s\n",
 		rsl_chan_nr_str(dl->chan_nr), tm.t1, tm.t2, tm.t3,
 		(int)dl->rx_level-110,
 		osmo_hexdump(ccch->data, sizeof(ccch->data)));
 
-	meas->last_fn = ntohl(dl->frame_nr);
-	meas->frames++;
-	meas->snr += dl->snr;
-	meas->berr += dl->num_biterr;
-	meas->rxlev += dl->rx_level;
-
-	/* counting loss criteria */
-	if (!(dl->link_id & 0x40)) {
-		switch (chan_type) {
-		case RSL_CHAN_PCH_AGCH:
-			/* only look at one CCCH frame in each 51 multiframe.
-			 * FIXME: implement DRX
-			 * - select correct paging block that is for us.
-			 * - initialize ds_fail according to BS_PA_MFRMS.
-			 */
-			if ((meas->last_fn % 51) != 6)
-				break;
-			if (!meas->ds_fail)
-				break;
-			if (dl->fire_crc >= 2)
-				meas->dsc -= 4;
-			else
-				meas->dsc += 1;
-			if (meas->dsc > meas->ds_fail)
-				meas->dsc = meas->ds_fail;
-			if (meas->dsc < meas->ds_fail)
-				LOGP(DL1C, LOGL_INFO, "LOSS counter for CCCH %d\n", meas->dsc);
-			if (meas->dsc > 0)
-				break;
-			meas->ds_fail = 0;
-			osmo_signal_dispatch(SS_L1CTL, S_L1CTL_LOSS_IND, ms);
-			break;
-		}
-	} else {
-		switch (chan_type) {
-		case RSL_CHAN_Bm_ACCHs:
-		case RSL_CHAN_Lm_ACCHs:
-		case RSL_CHAN_SDCCH4_ACCH:
-		case RSL_CHAN_SDCCH8_ACCH:
-			if (!meas->rl_fail)
-				break;
-			if (dl->fire_crc >= 2)
-				meas->s -= 1;
-			else
-				meas->s += 2;
-			if (meas->s > meas->rl_fail)
-				meas->s = meas->rl_fail;
-			if (meas->s < meas->rl_fail)
-				LOGP(DL1C, LOGL_NOTICE, "LOSS counter for ACCH %d\n", meas->s);
-			if (meas->s > 0)
-				break;
-			meas->rl_fail = 0;
-			osmo_signal_dispatch(SS_L1CTL, S_L1CTL_LOSS_IND, ms);
-			break;
-		}
-	}
-
-	if (dl->fire_crc >= 2) {
-		LOGP(DL1C, LOGL_NOTICE, "Dropping frame with %u bit errors\n",
-			dl->num_biterr);
-		msgb_free(msg);
-		return 0;
-	}
-
 	/* Send it up towards LAPDm via L23SAP */
 	return l23sap_data_ind(ms, msg);
 }
diff --git a/src/host/layer23/src/common/l23sap.c b/src/host/layer23/src/common/l23sap.c
index a34f5156..5a3e79e8 100644
--- a/src/host/layer23/src/common/l23sap.c
+++ b/src/host/layer23/src/common/l23sap.c
@@ -2,6 +2,7 @@
  * L23SAP (L2&3 Service Access Point), an interface between
  * L1 implementation and the upper layers (i.e. L2&3).
  *
+ * (C) 2010 by Andreas Eversberg <jolly@eversberg.eu>
  * (C) 2011 by Harald Welte <laforge@gnumonks.org>
  * (C) 2018 by Vadim Yanitskiy <axilirator@gmail.com>
  *
@@ -34,6 +35,7 @@
 #include <osmocom/core/logging.h>
 #include <osmocom/core/gsmtap_util.h>
 #include <osmocom/core/gsmtap.h>
+#include <osmocom/core/signal.h>
 #include <osmocom/core/prim.h>
 #include <osmocom/core/msgb.h>
 
@@ -47,6 +49,81 @@
 
 extern struct gsmtap_inst *gsmtap_inst;
 
+static int l23sap_check_dl_loss(struct osmocom_ms *ms,
+	struct l1ctl_info_dl *dl)
+{
+	struct rx_meas_stat *meas = &ms->meas;
+	uint8_t chan_type, chan_ts, chan_ss;
+
+	/* Update measurements */
+	meas->last_fn = ntohl(dl->frame_nr);
+	meas->frames++;
+	meas->snr += dl->snr;
+	meas->berr += dl->num_biterr;
+	meas->rxlev += dl->rx_level;
+
+	rsl_dec_chan_nr(dl->chan_nr, &chan_type, &chan_ss, &chan_ts);
+
+	/* counting loss criteria */
+	if (!CHAN_IS_SACCH(dl->link_id)) {
+		switch (chan_type) {
+		case RSL_CHAN_PCH_AGCH:
+			/* only look at one CCCH frame in each 51 multiframe.
+			 * FIXME: implement DRX
+			 * - select correct paging block that is for us.
+			 * - initialize ds_fail according to BS_PA_MFRMS.
+			 */
+			if ((meas->last_fn % 51) != 6)
+				break;
+			if (!meas->ds_fail)
+				break;
+			if (dl->fire_crc >= 2)
+				meas->dsc -= 4;
+			else
+				meas->dsc += 1;
+			if (meas->dsc > meas->ds_fail)
+				meas->dsc = meas->ds_fail;
+			if (meas->dsc < meas->ds_fail)
+				LOGP(DL23SAP, LOGL_INFO, "LOSS counter for CCCH %d\n", meas->dsc);
+			if (meas->dsc > 0)
+				break;
+			meas->ds_fail = 0;
+			osmo_signal_dispatch(SS_L1CTL, S_L1CTL_LOSS_IND, ms);
+			break;
+		}
+	} else {
+		switch (chan_type) {
+		case RSL_CHAN_Bm_ACCHs:
+		case RSL_CHAN_Lm_ACCHs:
+		case RSL_CHAN_SDCCH4_ACCH:
+		case RSL_CHAN_SDCCH8_ACCH:
+			if (!meas->rl_fail)
+				break;
+			if (dl->fire_crc >= 2)
+				meas->s -= 1;
+			else
+				meas->s += 2;
+			if (meas->s > meas->rl_fail)
+				meas->s = meas->rl_fail;
+			if (meas->s < meas->rl_fail)
+				LOGP(DL23SAP, LOGL_NOTICE, "LOSS counter for ACCH %d\n", meas->s);
+			if (meas->s > 0)
+				break;
+			meas->rl_fail = 0;
+			osmo_signal_dispatch(SS_L1CTL, S_L1CTL_LOSS_IND, ms);
+			break;
+		}
+	}
+
+	if (dl->fire_crc >= 2) {
+		LOGP(DL23SAP, LOGL_NOTICE, "Dropping frame with %u bit "
+			"errors\n", dl->num_biterr);
+		return -EBADMSG;
+	}
+
+	return 0;
+}
+
 int l23sap_gsmtap_data_ind(struct osmocom_ms *ms, struct msgb *msg)
 {
 	struct l1ctl_info_dl *dl = (struct l1ctl_info_dl *) msg->l1h;
@@ -102,6 +179,12 @@ int l23sap_data_ind(struct osmocom_ms *ms, struct msgb *msg)
 	struct osmo_phsap_prim pp;
 	struct lapdm_entity *le;
 
+	/* Check for decoding errors (path loss) */
+	if (l23sap_check_dl_loss(ms, dl)) {
+		msgb_free(msg);
+		return 0;
+	}
+
 	/* Init a new DATA IND primitive */
 	osmo_prim_init(&pp.oph, SAP_GSM_PH, PRIM_PH_DATA,
 		PRIM_OP_INDICATION, msg);