autobuild_mac80211_release/package/network/services/hostapd/patches/bp-0002-ACS-Introduce-acs_get_bw_center_chan.patch

From 3e2fa0f4ab02538c66e61058749272565d94d111 Mon Sep 17 00:00:00 2001
From: Nicolas Escande <nico.escande@gmail.com>
Date: Wed, 27 Apr 2022 15:37:00 +0200
Subject: [PATCH 02/50] ACS: Introduce acs_get_bw_center_chan()

When using 40/80/160 MHz bandwidth, instead of computing the index of
the segment center freq based on the selected channel, lets look it up
in the bw_desc[] table.

This is preparative work to allow selecting a primary channel which is
not the first of the segment.

Signed-off-by: Nicolas Escande <nico.escande@gmail.com>
---
 src/ap/acs.c | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/ap/acs.c b/src/ap/acs.c
index 60c90e9..511200d 100644
--- a/src/ap/acs.c
+++ b/src/ap/acs.c
@@ -436,6 +436,21 @@ static bool acs_usable_bw_chan(const struct hostapd_channel_data *chan,
 }
 
 
+static int acs_get_bw_center_chan(int freq, enum bw_type bw)
+{
+	unsigned int i = 0;
+
+	while (bw_desc[bw][i].first != -1) {
+		if (freq >= bw_desc[bw][i].first &&
+		    freq <= bw_desc[bw][i].last)
+			return bw_desc[bw][i].center_chan;
+		i++;
+	}
+
+	return 0;
+}
+
+
 static int acs_survey_is_sufficient(struct freq_survey *survey)
 {
 	if (!(survey->filled & SURVEY_HAS_NF)) {
@@ -936,19 +951,26 @@ bw_selected:
 
 static void acs_adjust_center_freq(struct hostapd_iface *iface)
 {
-	int offset;
+	int center;
 
 	wpa_printf(MSG_DEBUG, "ACS: Adjusting VHT center frequency");
 
 	switch (hostapd_get_oper_chwidth(iface->conf)) {
 	case CONF_OPER_CHWIDTH_USE_HT:
-		offset = 2 * iface->conf->secondary_channel;
+		if (iface->conf->secondary_channel &&
+		    iface->freq >= 2400 && iface->freq < 2500)
+			center = iface->conf->channel +
+				2 * iface->conf->secondary_channel;
+		else if (iface->conf->secondary_channel)
+			center = acs_get_bw_center_chan(iface->freq, ACS_BW40);
+		else
+			center = iface->conf->channel;
 		break;
 	case CONF_OPER_CHWIDTH_80MHZ:
-		offset = 6;
+		center = acs_get_bw_center_chan(iface->freq, ACS_BW80);
 		break;
 	case CONF_OPER_CHWIDTH_160MHZ:
-		offset = 14;
+		center = acs_get_bw_center_chan(iface->freq, ACS_BW160);
 		break;
 	default:
 		/* TODO: How can this be calculated? Adjust
@@ -958,8 +980,7 @@ static void acs_adjust_center_freq(struct hostapd_iface *iface)
 		return;
 	}
 
-	hostapd_set_oper_centr_freq_seg0_idx(iface->conf,
-					     iface->conf->channel + offset);
+	hostapd_set_oper_centr_freq_seg0_idx(iface->conf, center);
 }
 
 
-- 
2.18.0