cbch: Add counters; queue length limits and CBCH LOAD reporting

This adds the final missing part to full CBCH support:
* keep a tab on the current queue length for basic + extended CBCH
* keep rate counters about the number of sent / transmitted SMSCB
* send CBCH LOAD information via RSL to the BSC

Change-Id: I7068c7937a60a900c40439115bb84dc3ee0d061f

7 files changed, 137 insertions, 2 deletions

diff --git a/include/osmo-bts/cbch.h b/include/osmo-bts/cbch.h
index af5fd9a3..6bba5fa2 100644
--- a/include/osmo-bts/cbch.h
+++ b/include/osmo-bts/cbch.h
@@ -6,6 +6,14 @@
 #include <osmo-bts/gsm_data.h>
 #include <osmo-bts/bts.h>
 
+enum {
+	CBCH_CTR_RCVD_QUEUED,
+	CBCH_CTR_RCVD_DROPPED,
+	CBCH_CTR_SENT_SINGLE,
+	CBCH_CTR_SENT_DEFAULT,
+	CBCH_CTR_SENT_NULL,
+};
+
 /* incoming SMS broadcast command from RSL */
 int bts_process_smscb_cmd(struct gsm_bts *bts, struct rsl_ie_cb_cmd_type cmd_type,
 			  bool extended_cbch, uint8_t msg_len, const uint8_t *msg);
diff --git a/include/osmo-bts/gsm_data_shared.h b/include/osmo-bts/gsm_data_shared.h
index 860c296c..415e6bc0 100644
--- a/include/osmo-bts/gsm_data_shared.h
+++ b/include/osmo-bts/gsm_data_shared.h
@@ -542,6 +542,7 @@ struct gprs_rlc_cfg {
 struct bts_smscb_state {
 	struct llist_head queue; /* list of struct smscb_msg */
 	int queue_len;
+	struct rate_ctr_group *ctrs;
 	struct smscb_msg *cur_msg; /* current SMS-CB */
 	struct smscb_msg *default_msg; /* default broadcast message; NULL if none */
 };
@@ -744,6 +745,9 @@ struct gsm_bts {
 	/* State for SMSCB (Cell Broadcast) for BASIC and EXTENDED channel */
 	struct bts_smscb_state smscb_basic;
 	struct bts_smscb_state smscb_extended;
+	int smscb_queue_tgt_len; /* ideal/target queue length */
+	int smscb_queue_max_len; /* maximum queue length */
+	int smscb_queue_hyst; /* hysteresis for CBCH laod indications */
 
 	float min_qual_rach;	/* minimum quality for RACH bursts */
 	float min_qual_norm;	/* minimum quality for normal daata */
diff --git a/include/osmo-bts/rsl.h b/include/osmo-bts/rsl.h
index 0361841d..186018eb 100644
--- a/include/osmo-bts/rsl.h
+++ b/include/osmo-bts/rsl.h
@@ -43,4 +43,6 @@ void cb_ts_disconnected(struct gsm_bts_trx_ts *ts);
 void cb_ts_connected(struct gsm_bts_trx_ts *ts, int rc);
 void ipacc_dyn_pdch_complete(struct gsm_bts_trx_ts *ts, int rc);
 
+int rsl_tx_cbch_load_indication(struct gsm_bts *bts, bool ext_cbch, bool overflow, uint8_t amount);
+
 #endif // _RSL_H */
diff --git a/src/common/bts.c b/src/common/bts.c
index 4af219b1..5220406d 100644
--- a/src/common/bts.c
+++ b/src/common/bts.c
@@ -49,6 +49,7 @@
 #include <osmo-bts/oml.h>
 #include <osmo-bts/signal.h>
 #include <osmo-bts/dtx_dl_amr_fsm.h>
+#include <osmo-bts/cbch.h>
 
 #define MIN_QUAL_RACH    5.0f   /* at least  5 dB C/I */
 #define MIN_QUAL_NORM   -0.5f   /* at least -1 dB C/I */
@@ -105,6 +106,22 @@ static const struct rate_ctr_group_desc bts_ctrg_desc = {
 	bts_ctr_desc
 };
 
+static const struct rate_ctr_desc cbch_ctr_desc[] = {
+	[CBCH_CTR_RCVD_QUEUED] =	{"cbch:rcvd_queued", "Received + queued CBCH messages (Abis)" },
+	[CBCH_CTR_RCVD_DROPPED] =	{"cbch:rcvd_dropped", "Received + dropped CBCH messages (Abis)" },
+
+	[CBCH_CTR_SENT_SINGLE] =	{"cbch:sent_single", "Sent single CBCH messages (Um)" },
+	[CBCH_CTR_SENT_DEFAULT] =	{"cbch:sent_default", "Sent default CBCH messages (Um)" },
+	[CBCH_CTR_SENT_NULL] =		{"cbch:sent_null", "Sent NULL CBCH messages (Um)" },
+};
+static const struct rate_ctr_group_desc cbch_ctrg_desc = {
+	"cbch",
+	"cell broadcast channel",
+	OSMO_STATS_CLASS_GLOBAL,
+	ARRAY_SIZE(cbch_ctr_desc),
+	cbch_ctr_desc
+};
+
 /* Initialize the BTS data structures, called before config
  * file reading */
 int bts_init(struct gsm_bts *bts)
@@ -191,7 +208,15 @@ int bts_init(struct gsm_bts *bts)
 	}
 
 	INIT_LLIST_HEAD(&bts->smscb_basic.queue);
+	bts->smscb_basic.ctrs = rate_ctr_group_alloc(bts, &cbch_ctrg_desc, 0);
+	OSMO_ASSERT(bts->smscb_basic.ctrs);
 	INIT_LLIST_HEAD(&bts->smscb_extended.queue);
+	bts->smscb_extended.ctrs = rate_ctr_group_alloc(bts, &cbch_ctrg_desc, 1);
+	OSMO_ASSERT(bts->smscb_extended.ctrs);
+	bts->smscb_queue_max_len = 15;
+	bts->smscb_queue_tgt_len = 2;
+	bts->smscb_queue_hyst = 2;
+
 	INIT_LLIST_HEAD(&bts->oml_queue);
 
 	/* register DTX DL FSM */
diff --git a/src/common/cbch.c b/src/common/cbch.c
index 2107f115..6b65679f 100644
--- a/src/common/cbch.c
+++ b/src/common/cbch.c
@@ -26,6 +26,7 @@
 
 #include <osmo-bts/bts.h>
 #include <osmo-bts/cbch.h>
+#include <osmo-bts/rsl.h>
 #include <osmo-bts/logging.h>
 
 /* internal representation of one SMS-CB message (e.g. in the pending queue */
@@ -37,6 +38,28 @@ struct smscb_msg {
 	uint8_t num_segs;		/* total number of segments */
 };
 
+/* determine if current queue length differes more than permitted hysteresis from target
+ * queue length. If it does, send CBCH LOAD IND */
+static void check_and_send_cbch_load(struct gsm_bts *bts, struct bts_smscb_state *bts_ss)
+{
+	int delta = bts_ss->queue_len - bts->smscb_queue_tgt_len;
+	bool extended_cbch = false;
+
+	if (bts_ss == &bts->smscb_extended)
+		extended_cbch = true;
+
+	if (abs(delta) < bts->smscb_queue_hyst)
+		return;
+
+	if (delta < 0) {
+		/* Underrun */
+		rsl_tx_cbch_load_indication(bts, extended_cbch, false, OSMO_MIN(15, -delta));
+	} else {
+		/* Overrun */
+		rsl_tx_cbch_load_indication(bts, extended_cbch, true, OSMO_MIN(15, delta));
+	}
+}
+
 /* determine SMSCB state by tb number */
 static struct bts_smscb_state *bts_smscb_state(struct gsm_bts *bts, uint8_t tb)
 {
@@ -182,9 +205,16 @@ int bts_process_smscb_cmd(struct gsm_bts *bts, struct rsl_ie_cb_cmd_type cmd_typ
 	case RSL_CB_CMD_TYPE_SCHEDULE:
 	case RSL_CB_CMD_TYPE_NULL:
 		/* def_bcast is ignored as per Section 9.3.41 of 3GPP TS 48.058 */
+		/* limit queue size and optionally send CBCH LOAD Information (overflow) via RSL */
+		if (bts_ss->queue_len >= bts->smscb_queue_max_len) {
+			rate_ctr_inc2(bts_ss->ctrs, CBCH_CTR_RCVD_DROPPED);
+			talloc_free(scm);
+			break;
+		}
 		llist_add_tail(&scm->list, &bts_ss->queue);
 		bts_ss->queue_len++;
-		/* FIXME: limit queue size and optionally send CBCH LOAD Information (overflow) via RSL */
+		check_and_send_cbch_load(bts, bts_ss);
+		rate_ctr_inc2(bts_ss->ctrs, CBCH_CTR_RCVD_QUEUED);
 		break;
 	case RSL_CB_CMD_TYPE_DEFAULT:
 		/* old default msg will be free'd in get_smscb_block() if it is currently in transit
@@ -217,20 +247,25 @@ static struct smscb_msg *select_next_smscb(struct gsm_bts *bts, uint8_t tb)
 	if (msg) {
 		llist_del(&msg->list);
 		bts_ss->queue_len--;
+		check_and_send_cbch_load(bts, bts_ss);
 		DEBUGP(DLSMS, "%s: Dequeued msg\n", __func__);
+		rate_ctr_inc2(bts_ss->ctrs, CBCH_CTR_SENT_SINGLE);
 		return msg;
 	}
 
-	/* FIXME: send CBCH LOAD Information (underflow) via RSL */
+	/* send CBCH LOAD Information (underflow) via RSL */
+	check_and_send_cbch_load(bts, bts_ss);
 
 	/* choose the default message, if any */
 	msg = bts_ss->default_msg;
 	if (msg) {
 		DEBUGP(DLSMS, "%s: Using default msg\n", __func__);
+		rate_ctr_inc2(bts_ss->ctrs, CBCH_CTR_SENT_DEFAULT);
 		return msg;
 	}
 
 	DEBUGP(DLSMS, "%s: No queued msg nor default\n", __func__);
+	rate_ctr_inc2(bts_ss->ctrs, CBCH_CTR_SENT_NULL);
 	return NULL;
 }
 
diff --git a/src/common/rsl.c b/src/common/rsl.c
index 364e8291..af0b72d1 100644
--- a/src/common/rsl.c
+++ b/src/common/rsl.c
@@ -1636,6 +1636,32 @@ static int rsl_rx_sacch_inf_mod(struct msgb *msg)
 	return 0;
 }
 
+/* 8.5.8 CBCH Load Information */
+int rsl_tx_cbch_load_indication(struct gsm_bts *bts, bool ext_cbch, bool overflow, uint8_t amount)
+{
+	struct gsm_lchan *lchan = gsm_bts_get_cbch(bts);
+	struct msgb *msg;
+	uint8_t load_info;
+
+	msg = rsl_msgb_alloc(sizeof(struct abis_rsl_cchan_hdr));
+	if (!msg)
+		return -ENOMEM;
+
+	/* 9.3.1 Channel Number */
+	rsl_cch_push_hdr(msg, RSL_MT_CBCH_LOAD_IND, gsm_lchan2chan_nr(lchan));
+
+	/* 9.3.43 CBCH Load Information */
+	load_info = ((overflow & 1) << 7) | (amount & 0x0F);
+	msgb_tv_put(msg, RSL_IE_CBCH_LOAD_INFO, load_info);
+	/* 9.3.44 SMSCB Channel Indicator */
+	if (ext_cbch)
+		msgb_tv_put(msg, RSL_IE_SMSCB_CHAN_INDICATOR, 0x01);
+
+	msg->trx = bts->c0;
+
+	return abis_bts_rsl_sendmsg(msg);
+}
+
 /*
  * ip.access related messages
  */
diff --git a/src/common/vty.c b/src/common/vty.c
index fab55161..1d25bfb5 100644
--- a/src/common/vty.c
+++ b/src/common/vty.c
@@ -310,6 +310,9 @@ static void config_write_bts_single(struct vty *vty, struct gsm_bts *bts)
 		vty_out(vty, " pcu-socket %s%s", bts->pcu.sock_path, VTY_NEWLINE);
 	if (bts->supp_meas_toa256)
 		vty_out(vty, " supp-meas-info toa256%s", VTY_NEWLINE);
+	vty_out(vty, " smscb queue-max-length %d%s", bts->smscb_queue_max_len, VTY_NEWLINE);
+	vty_out(vty, " smscb queue-target-length %d%s", bts->smscb_queue_tgt_len, VTY_NEWLINE);
+	vty_out(vty, " smscb queue-hysteresis %d%s", bts->smscb_queue_hyst, VTY_NEWLINE);
 
 	bts_model_config_write_bts(vty, bts);
 
@@ -687,6 +690,33 @@ DEFUN(cfg_bts_no_supp_meas_toa256, cfg_bts_no_supp_meas_toa256_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_bts_smscb_max_qlen, cfg_bts_smscb_max_qlen_cmd,
+	"smscb queue-max-length <1-60>",
+	"Maximum queue length for SMSCB (CBCH) queue. In count of messages/pages (Default: 15)")
+{
+	struct gsm_bts *bts = vty->index;
+	bts->smscb_queue_max_len = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_bts_smscb_tgt_qlen, cfg_bts_smscb_tgt_qlen_cmd,
+	"smscb queue-target-length <1-30>",
+	"Target queue length for SMSCB (CBCH) queue. In count of messages/pages (Default: 2)")
+{
+	struct gsm_bts *bts = vty->index;
+	bts->smscb_queue_tgt_len = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_bts_smscb_qhyst, cfg_bts_smscb_qhyst_cmd,
+	"smscb queue-hysteresis <0-30>",
+	"Hysteresis for SMSCB (CBCH) queue. In count of messages/pages (Default: 2)")
+{
+	struct gsm_bts *bts = vty->index;
+	bts->smscb_queue_hyst = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
 
 #define DB_DBM_STR 							\
 	"Unit is dB (decibels)\n"					\
@@ -854,6 +884,8 @@ static void bts_dump_vty(struct vty *vty, struct gsm_bts *bts)
 		bts->agch_queue.rejected_msgs, bts->agch_queue.agch_msgs,
 		bts->agch_queue.pch_msgs,
 		VTY_NEWLINE);
+	vty_out(vty, "  CBCH queue target: %d, hysteresis: %d, maximum: %d%s",
+		bts->smscb_queue_tgt_len, bts->smscb_queue_max_len, bts->smscb_queue_hyst, VTY_NEWLINE);
 	vty_out(vty, "  CBCH backlog queue length (BASIC): %d%s",
 		bts->smscb_basic.queue_len, VTY_NEWLINE);
 	vty_out(vty, "  CBCH backlog queue length (EXTENDED): %u%s",
@@ -1614,6 +1646,9 @@ int bts_vty_init(struct gsm_bts *bts, const struct log_info *cat)
 	install_element(BTS_NODE, &cfg_bts_pcu_sock_cmd);
 	install_element(BTS_NODE, &cfg_bts_supp_meas_toa256_cmd);
 	install_element(BTS_NODE, &cfg_bts_no_supp_meas_toa256_cmd);
+	install_element(BTS_NODE, &cfg_bts_smscb_max_qlen_cmd);
+	install_element(BTS_NODE, &cfg_bts_smscb_tgt_qlen_cmd);
+	install_element(BTS_NODE, &cfg_bts_smscb_qhyst_cmd);
 
 	install_element(BTS_NODE, &cfg_trx_gsmtap_sapi_cmd);
 	install_element(BTS_NODE, &cfg_trx_no_gsmtap_sapi_cmd);