RES IND: parse msg and store interference levels in lchans

Also show the current interference levels of unused lchans in the vty.

Related: SYS#5313
Change-Id: Iccc1391e8419604bb09e464db8455e053dfbc982

4 files changed, 106 insertions, 3 deletions

diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index b07345de0..063294432 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -646,6 +646,9 @@ struct lchan_modify_info {
 	bool vamos;
 };
 
+#define INTERF_DBM_UNKNOWN 0
+#define INTERF_BAND_UNKNOWN 0xff
+
 struct gsm_lchan {
 	/* The TS that we're part of */
 	struct gsm_bts_trx_ts *ts;
@@ -781,6 +784,14 @@ struct gsm_lchan {
 		/* Whether this lchan is activated/modified into a mode that allows VAMOS multiplexing at this moment */
 		bool enabled;
 	} vamos;
+
+	/* dBm value of interference level as reported in the most recent Resource Indication, if any for this lchan. Or
+	 * INTERF_DBM_UNKNOWN if this lchan was not included in the most recent Resource Indication.
+	 * The range is typically -115 to -85 dBm, here stored 1:1 as a signed integer, to ease comparison. */
+	int16_t interf_dbm;
+	/* Actual reported interference band index, or INTERF_BAND_UNKNOWN if this lchan was not included in the most
+	 * recent Resource Indication. */
+	uint8_t interf_band;
 };
 
 /* One Timeslot in a TRX */
diff --git a/src/osmo-bsc/abis_rsl.c b/src/osmo-bsc/abis_rsl.c
index f0adc566f..f941d7e2b 100644
--- a/src/osmo-bsc/abis_rsl.c
+++ b/src/osmo-bsc/abis_rsl.c
@@ -1467,6 +1467,75 @@ static int rsl_rx_error_rep(struct msgb *msg)
 	return 0;
 }
 
+static int rsl_rx_resource_indication(struct msgb *msg)
+{
+	struct abis_rsl_common_hdr *rslh = msgb_l2(msg);
+	struct tlv_parsed tp;
+	struct e1inp_sign_link *sign_link = msg->dst;
+	struct tlv_p_entry *res_info_ie;
+	struct gsm_bts_trx *trx = sign_link->trx;
+	struct gsm_lchan *lchan;
+	int ts_nr;
+	int i;
+
+	rsl_tlv_parse(&tp, rslh->data, msgb_l2len(msg) - sizeof(*rslh));
+
+	LOGP(DRSL, LOGL_DEBUG, "%s Rx Resource Indication\n", gsm_trx_name(trx));
+
+	/* First clear out all ratings, because only the last resource indication counts. If we can't parse the message,
+	 * then there are no ratings. */
+	for (ts_nr = 0; ts_nr < TRX_NR_TS; ts_nr++) {
+		struct gsm_bts_trx_ts *ts = &trx->ts[ts_nr];
+		ts_for_n_lchans(lchan, ts, ts->max_lchans_possible) {
+			lchan->interf_dbm = INTERF_DBM_UNKNOWN;
+			lchan->interf_band = INTERF_BAND_UNKNOWN;
+		}
+	}
+
+	res_info_ie = TLVP_GET_MINLEN(&tp, RSL_IE_RESOURCE_INFO, 2);
+	if (!res_info_ie) {
+		LOGP(DRSL, LOGL_ERROR, "Rx Resource Indication: missing Resource Info IE\n");
+		return -ENOENT;
+	}
+
+	/* The IE value is defined in 3GPP TS 48.058 9.3.21 Resource Information:
+	 * one octet channel nr, one octet interference level, channel nr, interference level, ...
+	 * Where channel nr is cbits + tn (as usual),
+	 * and interference level is a 3bit value in the most significant bits of the octet.
+	 * Evaluate each pair and update interference ratings for all lchans in this trx. */
+
+	/* There must be an even amount of octets in the value */
+	if (res_info_ie->len & 1) {
+		LOGP(DRSL, LOGL_ERROR, "Rx Resource Indication: Resource Info IE has odd length\n");
+		return -EINVAL;
+	}
+
+	/* Now iterate the reported levels and update corresponding lchans */
+	for (i = 0; i < res_info_ie->len; i += 2) {
+		struct gsm_bts *bts = trx->bts;
+		uint8_t chan_nr = res_info_ie->val[i];
+		uint8_t interf_band = res_info_ie->val[i + 1] >> 5;
+
+		lchan = lchan_lookup(trx, chan_nr, "Abis RSL Rx Resource Indication: ");
+		if (!lchan)
+			continue;
+
+		/* Store the actual received index */
+		lchan->interf_band = interf_band;
+		/* Clamp the index to 5 before accessing array of interference band bounds */
+		interf_band = OSMO_MIN(interf_band, ARRAY_SIZE(bts->interf_meas_params.bounds_dbm)-1);
+		/* FIXME: when testing with ip.access nanoBTS, we observe a value range of 1..6. According to spec, it
+		 * seems like values 0..5 are intended: 3GPP TS 48.058 9.3.21 Resource Information says:
+		 * "The Interf Band field (bits 6-8) indicates in binary the interference level expressed as one of five
+		 * possible interference level bands as defined by O&M."
+		 * and 3GPP TS 52.021 9.4.25 "Interference level Boundaries" (OML) defines values 0, X1, X2, X3, X4, X5.
+		 * If nanoBTS sends 6, the above code clamps it to 5, so that we lose one band in accuracy. */
+		lchan->interf_dbm = -((int16_t)bts->interf_meas_params.bounds_dbm[interf_band]);
+	}
+
+	return 0;
+}
+
 static int abis_rsl_rx_trx(struct msgb *msg)
 {
 	struct abis_rsl_common_hdr *rslh = msgb_l2(msg);
@@ -1479,7 +1548,7 @@ static int abis_rsl_rx_trx(struct msgb *msg)
 		break;
 	case RSL_MT_RF_RES_IND:
 		/* interference on idle channels of TRX */
-		//DEBUGP(DRSL, "%s RF Resource Indication\n", gsm_trx_name(sign_link->trx));
+		rc = rsl_rx_resource_indication(msg);
 		break;
 	case RSL_MT_OVERLOAD:
 		/* indicate CCCH / ACCH / processor overload */
diff --git a/src/osmo-bsc/bsc_vty.c b/src/osmo-bsc/bsc_vty.c
index 070b66081..07c8a9c9e 100644
--- a/src/osmo-bsc/bsc_vty.c
+++ b/src/osmo-bsc/bsc_vty.c
@@ -1682,6 +1682,14 @@ static void lchan_dump_full_vty(struct vty *vty, struct gsm_lchan *lchan)
 		- lchan->bs_power_db,
 		ms_pwr_dbm(lchan->ts->trx->bts->band, lchan->ms_power),
 		VTY_NEWLINE);
+
+	vty_out(vty, "  Interference Level: ");
+	if (lchan->interf_dbm == INTERF_DBM_UNKNOWN)
+		vty_out(vty, "unknown");
+	else
+		vty_out(vty, "%d dBm (%u)", lchan->interf_dbm, lchan->interf_band);
+	vty_out(vty, "%s", VTY_NEWLINE);
+
 	vty_out(vty, "  Channel Mode / Codec: %s%s",
 		gsm48_chan_mode_name(lchan->current_ch_mode_rate.chan_mode),
 		VTY_NEWLINE);
@@ -1733,8 +1741,21 @@ static void lchan_dump_short_vty(struct vty *vty, struct gsm_lchan *lchan)
 		lchan->ts->trx->bts->nr, lchan->ts->trx->nr, lchan->ts->nr,
 		gsm_pchan_name(lchan->ts->pchan_on_init));
 	vty_out_dyn_ts_status(vty, lchan->ts);
-	vty_out(vty, ", Lchan %u, Type %s%s TSC-s%dc%u, State %s - L1 MS Power: %u dBm RXL-FULL-dl: %4d dBm RXL-FULL-ul: %4d dBm%s",
-		lchan->nr,
+	vty_out(vty, ", Lchan %u", lchan->nr);
+
+	if (lchan_state_is(lchan, LCHAN_ST_UNUSED)) {
+		vty_out(vty, ", Type %s, State %s - Interference Level: ",
+			gsm_pchan_name(lchan->ts->pchan_is),
+			lchan_state_name(lchan));
+		if (lchan->interf_dbm == INTERF_DBM_UNKNOWN)
+			vty_out(vty, "unknown");
+		else
+			vty_out(vty, "%d dBm (%u)", lchan->interf_dbm, lchan->interf_band);
+		vty_out(vty, "%s", VTY_NEWLINE);
+		return;
+	}
+
+	vty_out(vty, ", Type %s%s TSC-s%dc%u, State %s - L1 MS Power: %u dBm RXL-FULL-dl: %4d dBm RXL-FULL-ul: %4d dBm%s",
 		gsm_lchant_name(lchan->type),
 		lchan->vamos.enabled ? " (VAMOS)" : "",
 		lchan->tsc_set > 0 ? lchan->tsc_set : 1,
diff --git a/src/osmo-bsc/lchan_fsm.c b/src/osmo-bsc/lchan_fsm.c
index e1dacb3af..7b89b2db5 100644
--- a/src/osmo-bsc/lchan_fsm.c
+++ b/src/osmo-bsc/lchan_fsm.c
@@ -488,6 +488,8 @@ static void lchan_reset(struct gsm_lchan *lchan)
 		.release.rr_cause = GSM48_RR_CAUSE_NORMAL,
 
 		.tsc_set = 1,
+		.interf_dbm = INTERF_DBM_UNKNOWN,
+		.interf_band = INTERF_BAND_UNKNOWN,
 	};
 }