From af832aa998200615766726f1184aabbb9a884d15 Mon Sep 17 00:00:00 2001
From: Bhagavathi Perumal S <bperumal@qti.qualcomm.com>
Date: Mon, 4 Dec 2017 14:53:33 +0530
Subject: [PATCH] hostapd: Add average channel utilization in STATUS

This allows external programs to get the average channel utilization.
The average channel utilization is calculated and reported through
STATUS command. Users need to configure chan_util_avg_period and
bss_load_update_period in hostapd config to get the average channel
utilization.

Signed-off-by: Bhagavathi Perumal S <bperumal@qti.qualcomm.com>
---
 hostapd/config_file.c  | 10 ++++++++++
 hostapd/hostapd.conf   |  6 ++++++
 src/ap/ap_config.h     |  1 +
 src/ap/bss_load.c      | 16 ++++++++++++++++
 src/ap/ctrl_iface_ap.c |  9 +++++++++
 src/ap/hostapd.h       |  4 ++++
 6 files changed, 46 insertions(+)

diff --git a/hostapd/config_file.c b/hostapd/config_file.c
index f1e84b7c9..289180428 100644
--- a/hostapd/config_file.c
+++ b/hostapd/config_file.c
@@ -2863,6 +2863,16 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 			return 1;
 		}
 		bss->bss_load_update_period = val;
+	} else if (os_strcmp(buf, "chan_util_avg_period") == 0) {
+		int val = atoi(pos);
+
+		if (val < 0) {
+			wpa_printf(MSG_ERROR,
+				   "Line %d: invalid chan_util_avg_period",
+				   line);
+			return 1;
+		}
+		bss->chan_util_avg_period = val;
 	} else if (os_strcmp(buf, "rts_threshold") == 0) {
 		conf->rts_threshold = atoi(pos);
 		if (conf->rts_threshold < -1 || conf->rts_threshold > 65535) {
diff --git a/hostapd/hostapd.conf b/hostapd/hostapd.conf
index 140c8d6ff..0d49fd744 100644
--- a/hostapd/hostapd.conf
+++ b/hostapd/hostapd.conf
@@ -511,6 +511,12 @@ wmm_ac_vo_acm=0
 # Beacon and Probe Response frames.
 #bss_load_update_period=50
 
+# Channel utilization averaging period (in BUs)
+# This field is used to enable and configure channel utilization average
+# calculation with bss_load_update_period. This should be in multiples of
+# bss_load_update_period for more accurate calculation.
+#chan_util_avg_period=600
+
 # Fixed BSS Load value for testing purposes
 # This field can be used to configure hostapd to add a fixed BSS Load element
 # into Beacon and Probe Response frames for testing purposes. The format is
diff --git a/src/ap/ap_config.h b/src/ap/ap_config.h
index fa99d3750..dc0686e69 100644
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -249,6 +249,7 @@ struct hostapd_bss_config {
 
 	int dtim_period;
 	unsigned int bss_load_update_period;
+	unsigned int chan_util_avg_period;
 
 	int ieee802_1x; /* use IEEE 802.1X */
 	int eapol_version;
diff --git a/src/ap/bss_load.c b/src/ap/bss_load.c
index ef2d36be3..725d3cd34 100644
--- a/src/ap/bss_load.c
+++ b/src/ap/bss_load.c
@@ -44,6 +44,7 @@ static void update_channel_utilization(void *eloop_data, void *user_data)
 	struct hostapd_data *hapd = eloop_data;
 	unsigned int sec, usec;
 	int err;
+	struct hostapd_iface *iface = hapd->iface;
 
 	if (!(hapd->beacon_set_done && hapd->started))
 		return;
@@ -59,6 +60,21 @@ static void update_channel_utilization(void *eloop_data, void *user_data)
 	if (get_bss_load_update_timeout(hapd, &sec, &usec) < 0)
 		return;
 
+	if (hapd->conf->chan_util_avg_period) {
+		iface->chan_util_samples_sum += iface->channel_utilization;
+		iface->chan_util_num_sample_periods +=
+			hapd->conf->bss_load_update_period;
+		if (iface->chan_util_num_sample_periods >=
+		    hapd->conf->chan_util_avg_period) {
+			iface->chan_util_average =
+				iface->chan_util_samples_sum /
+				(iface->chan_util_num_sample_periods /
+				 hapd->conf->bss_load_update_period);
+			iface->chan_util_samples_sum = 0;
+			iface->chan_util_num_sample_periods = 0;
+		}
+	}
+
 	eloop_register_timeout(sec, usec, update_channel_utilization, hapd,
 			       NULL);
 }
diff --git a/src/ap/ctrl_iface_ap.c b/src/ap/ctrl_iface_ap.c
index 74d3a2577..883b005b2 100644
--- a/src/ap/ctrl_iface_ap.c
+++ b/src/ap/ctrl_iface_ap.c
@@ -795,6 +795,15 @@ int hostapd_ctrl_iface_status(struct hostapd_data *hapd, char *buf,
 		len += ret;
 	}
 
+	if (hapd->conf->chan_util_avg_period) {
+		ret = os_snprintf(buf + len, buflen - len,
+				  "chan_util_avg=%u\n",
+				  iface->chan_util_average);
+		if (os_snprintf_error(buflen - len, ret))
+			return len;
+		len += ret;
+	}
+
 	return len;
 }
 
diff --git a/src/ap/hostapd.h b/src/ap/hostapd.h
index 2c095dcfa..0e35ee80a 100644
--- a/src/ap/hostapd.h
+++ b/src/ap/hostapd.h
@@ -497,6 +497,10 @@ struct hostapd_iface {
 	u64 last_channel_time_busy;
 	u8 channel_utilization;
 
+	unsigned int chan_util_samples_sum;
+	unsigned int chan_util_num_sample_periods;
+	unsigned int chan_util_average;
+
 	/* eCSA IE will be added only if operating class is specified */
 	u8 cs_oper_class;