From 3975ed290f4d1dd7340595296fc8d39be6a41486 Mon Sep 17 00:00:00 2001
From: Aloka Dixit <quic_alokad@quicinc.com>
Date: Thu, 31 Mar 2022 15:17:47 -0700
Subject: [PATCH 2/3] acs: generate puncturing bitmap

Generate puncturing bitmap after the ideal channel selection using
the threshold.

Signed-off-by: Aloka Dixit <quic_alokad@quicinc.com>
---
 src/ap/acs.c         | 72 +++++++++++++++++++++++++++++++++++++++++---
 src/drivers/driver.h |  5 +++
 2 files changed, 73 insertions(+), 4 deletions(-)

--- a/src/ap/acs.c
+++ b/src/ap/acs.c
@@ -275,6 +275,7 @@ static void acs_cleanup_mode(struct host
 		dl_list_init(&chan->survey_list);
 		chan->flag |= HOSTAPD_CHAN_SURVEY_LIST_INITIALIZED;
 		chan->min_nf = 0;
+		chan->ru_punct_bitmap = 0;
 	}
 }
 
@@ -644,6 +645,49 @@ static int is_common_24ghz_chan(int chan
 #define ACS_24GHZ_PREFER_1_6_11 0.8
 #endif /* ACS_24GHZ_PREFER_1_6_11 */
 
+static void acs_update_puncturing_bitmap(struct hostapd_iface *iface,
+					 struct hostapd_hw_modes *mode, u32 bw,
+					 int n_chans,
+					 struct hostapd_channel_data *chan,
+					 long double factor,
+					 int index_primary)
+{
+	struct hostapd_channel_data *adj_chan = NULL;
+	int i;
+	struct hostapd_config *conf = iface->conf;
+	long double threshold = factor * conf->ru_punct_acs_threshold / 100;
+
+	/*
+	 * If threshold is 0 or user configured puncturing pattern is
+	 * available then don't add additional puncturing.
+	 */
+	if (!conf->ru_punct_acs_threshold || conf->ru_punct_bitmap)
+		return;
+
+	if (is_24ghz_mode(mode->mode) || (bw < 80))
+		return;
+
+	for (i = 0; i < n_chans; i++) {
+		if (i == index_primary)
+			continue; /* cannot puncture primary channel */
+
+		if (i > index_primary)
+			adj_chan = acs_find_chan(iface,
+						 chan->freq +
+						 ((i - index_primary) * 20));
+		else
+			adj_chan = acs_find_chan(iface,
+						 chan->freq -
+						 ((index_primary - i) * 20));
+
+		if (!adj_chan)
+			break;
+
+		if (adj_chan->interference_factor > threshold)
+			chan->ru_punct_bitmap |= BIT(i);
+	}
+}
+
 static void
 acs_find_6g_psc_chan_mode(struct hostapd_iface *iface,
 			  struct hostapd_hw_modes *mode,
@@ -740,8 +784,17 @@ acs_find_6g_psc_chan_mode(struct hostapd
 
 		if (acs_usable_chan(chan) &&
 		   (!*ideal_chan || factor < *ideal_factor)) {
-		    *ideal_factor = factor;
+			/* reset puncturing bitmap for the previous ideal channel */
+			if (*ideal_chan)
+				(*ideal_chan)->ru_punct_bitmap = 0;
+
+			*ideal_factor = factor;
 			*ideal_chan = chan;
+
+			if (iface->conf->ieee80211ax)
+				acs_update_puncturing_bitmap(iface, mode, bw,
+							     n_chans, chan,
+							     factor, 0);
 		}
 
 		/* This channel would at least be usable */
@@ -772,7 +825,11 @@ acs_find_ideal_chan_mode(struct hostapd_
 		/* Since in the current ACS implementation the first channel is
 		 * always a primary channel, skip channels not available as
 		 * primary until more sophisticated channel selection is
-		 * implemented. */
+		 * implemented.
+		 * If this implementation is changed to allow any channel in
+		 * the bandwidth to be the primary one, the last parameter to
+		 * acs_update_puncturing_bitmap() should be changed to the index
+		 * of the primary channel */
 		if (!chan_pri_allowed(chan))
 			continue;
 
@@ -923,8 +980,17 @@ acs_find_ideal_chan_mode(struct hostapd_
 
 		if (acs_usable_chan(chan) &&
 		    (!*ideal_chan || factor < *ideal_factor)) {
+			/* reset puncturing bitmap for the previous ideal channel */
+			if (*ideal_chan)
+				(*ideal_chan)->ru_punct_bitmap = 0;
+
 			*ideal_factor = factor;
 			*ideal_chan = chan;
+
+			if (iface->conf->ieee80211ax)
+				acs_update_puncturing_bitmap(iface, mode, bw,
+							     n_chans, chan,
+							     factor, 0);
 		}
 
 		/* This channel would at least be usable */
@@ -1006,9 +1072,18 @@ bw_selected:
 	if (ideal_chan) {
 		wpa_printf(MSG_DEBUG, "ACS: Ideal channel is %d (%d MHz) with total interference factor of %Lg",
 			   ideal_chan->chan, ideal_chan->freq, ideal_factor);
+
+		if (iface->conf->ru_punct_acs_threshold)
+			wpa_printf(MSG_DEBUG, "ACS: RU puncturing bitmap 0x%x",
+				   ideal_chan->ru_punct_bitmap);
+
 		return ideal_chan;
 	}
 
+	if (iface->conf->ru_punct_acs_threshold)
+		wpa_printf(MSG_DEBUG, "ACS: RU puncturing bitmap 0x%x",
+			   ideal_chan->ru_punct_bitmap);
+
 	return rand_chan;
 }
 
@@ -1116,6 +1191,7 @@ static void acs_study(struct hostapd_ifa
 
 	iface->conf->channel = ideal_chan->chan;
 	iface->freq = ideal_chan->freq;
+	iface->conf->ru_punct_bitmap = ideal_chan->ru_punct_bitmap;
 
 	if (iface->conf->ieee80211ac || iface->conf->ieee80211ax)
 		acs_adjust_center_freq(iface);
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -181,6 +181,11 @@ struct hostapd_channel_data {
 	 * wmm_rules - WMM regulatory rules
 	 */
 	struct hostapd_wmm_rule wmm_rules[WMM_AC_NUM];
+
+	/**
+	 * ru_punct_bitmap - RU puncturing bitmap
+	 */
+	u16 ru_punct_bitmap;
 };
 
 #define HE_MAC_CAPAB_0		0