From 5a471a9025d9bf2a871339f5306e5c9050357703 Mon Sep 17 00:00:00 2001
From: Michael-CY Lee <michael-cy.lee@mediatek.com>
Date: Mon, 29 Jan 2024 10:26:53 +0800
Subject: [PATCH 077/104] Revert ACS upstream changes

- 348c047af ACS: More consistent checking of the best channel pointer
- 98f3bd26d ACS: Extend the 320 MHz support
- 733de8568 ACS: Fix not selecting the best channel in the segment
- dc57ede01 tests: Full validation of ACS selecting HT40- channel
- 4881accbb ACS: Add HT40- support in the 2.4 GHz band
- 29f38ebcf ACS: Check whether iface->current_mode is NULL before use
- 6f014c0d0 ACS: Add 320 MHz support for EHT

Note that "e6f2494c3 hostapd: Add eht_bw320_offset configuration option"
is not reverted due to conflict.
---
 src/ap/acs.c               | 160 +++++++++----------------------------
 tests/hwsim/test_ap_acs.py |  19 ++---
 2 files changed, 41 insertions(+), 138 deletions(-)

diff --git a/src/ap/acs.c b/src/ap/acs.c
index cb4db7147..cfa4a7d27 100644
--- a/src/ap/acs.c
+++ b/src/ap/acs.c
@@ -245,8 +245,6 @@ enum bw_type {
 	ACS_BW40,
 	ACS_BW80,
 	ACS_BW160,
-	ACS_BW320_1,
-	ACS_BW320_2,
 };
 
 struct bw_item {
@@ -288,20 +286,10 @@ static const struct bw_item bw_160[] = {
 	{ 6435, 6575, 111 }, { 6595, 6735, 143 },
 	{ 6755, 6895, 175 }, { 6915, 7055, 207 }, { -1, -1, -1 }
 };
-static const struct bw_item bw_320_1[] = {
-	{ 5955, 6255, 31 }, { 6275, 6575, 95 }, { 6595, 6895, 159 },
-	{ -1, -1, -1 }
-};
-static const struct bw_item bw_320_2[] = {
-	{ 6115, 6415, 63 }, { 6435, 6735, 127 }, { 6755, 7055, 191 },
-	{ -1, -1, -1 }
-};
 static const struct bw_item *bw_desc[] = {
 	[ACS_BW40] = bw_40,
 	[ACS_BW80] = bw_80,
 	[ACS_BW160] = bw_160,
-	[ACS_BW320_1] = bw_320_1,
-	[ACS_BW320_2] = bw_320_2,
 };
 
 
@@ -773,42 +761,6 @@ static void acs_update_puncturing_bitmap(struct hostapd_iface *iface,
 #endif /* CONFIG_IEEE80211BE */
 
 
-static bool
-acs_usable_bw320_chan(struct hostapd_iface *iface,
-		      struct hostapd_channel_data *chan, int *bw320_offset)
-{
-	const char *bw320_str[] = { "320 MHz", "320 MHz-1", "320 MHz-2" };
-	int conf_bw320_offset = hostapd_get_bw320_offset(iface->conf);
-
-	*bw320_offset = 0;
-	switch (conf_bw320_offset) {
-	case 1:
-		if (acs_usable_bw_chan(chan, ACS_BW320_1))
-			*bw320_offset = 1;
-		break;
-	case 2:
-		if (acs_usable_bw_chan(chan, ACS_BW320_2))
-			*bw320_offset = 2;
-		break;
-	case 0:
-	default:
-		conf_bw320_offset = 0;
-		if (acs_usable_bw_chan(chan, ACS_BW320_1))
-			*bw320_offset = 1;
-		else if (acs_usable_bw_chan(chan, ACS_BW320_2))
-			*bw320_offset = 2;
-		break;
-	}
-
-	if (!*bw320_offset)
-		wpa_printf(MSG_DEBUG,
-			   "ACS: Channel %d: not allowed as primary channel for %s bandwidth",
-			   chan->chan, bw320_str[conf_bw320_offset]);
-
-	return *bw320_offset != 0;
-}
-
-
 static void
 acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 			 struct hostapd_hw_modes *mode,
@@ -820,18 +772,14 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 	struct hostapd_channel_data *chan, *adj_chan = NULL, *best;
 	long double factor;
 	int i, j;
-	int bw320_offset = 0, ideal_bw320_offset = 0;
 	unsigned int k;
-	int secondary_channel = 1, freq_offset;
-
-	if (is_24ghz_mode(mode->mode))
-		secondary_channel = iface->conf->secondary_channel;
 
 	for (i = 0; i < mode->num_channels; i++) {
-		double total_weight = 0;
+		double total_weight;
 		struct acs_bias *bias, tmp_bias;
+		bool update_best = true;
 
-		chan = &mode->channels[i];
+		best = chan = &mode->channels[i];
 
 		/* Since in the current ACS implementation the first channel is
 		 * always a primary channel, skip channels not available as
@@ -863,7 +811,7 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 		    iface->conf->country[2] == 0x4f)
 			continue;
 
-		if (!chan_bw_allowed(chan, bw, secondary_channel != -1, 1)) {
+		if (!chan_bw_allowed(chan, bw, 1, 1)) {
 			wpa_printf(MSG_DEBUG,
 				   "ACS: Channel %d: BW %u is not supported",
 				   chan->chan, bw);
@@ -884,8 +832,7 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 		}
 
 		if (mode->mode == HOSTAPD_MODE_IEEE80211A &&
-		    (iface->conf->ieee80211ac || iface->conf->ieee80211ax ||
-		     iface->conf->ieee80211be)) {
+		    (iface->conf->ieee80211ac || iface->conf->ieee80211ax)) {
 			if (hostapd_get_oper_chwidth(iface->conf) ==
 			    CONF_OPER_CHWIDTH_80MHZ &&
 			    !acs_usable_bw_chan(chan, ACS_BW80)) {
@@ -905,25 +852,13 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 			}
 		}
 
-		if (mode->mode == HOSTAPD_MODE_IEEE80211A &&
-		    iface->conf->ieee80211be) {
-			if (hostapd_get_oper_chwidth(iface->conf) ==
-			    CONF_OPER_CHWIDTH_320MHZ &&
-			    !acs_usable_bw320_chan(iface, chan, &bw320_offset))
-				continue;
-		}
-
 		factor = 0;
-		best = NULL;
-		if (acs_usable_chan(chan)) {
+		if (acs_usable_chan(chan))
 			factor = chan->interference_factor;
-			total_weight = 1;
-			best = chan;
-		}
+		total_weight = 1;
 
 		for (j = 1; j < n_chans; j++) {
-			adj_chan = acs_find_chan(iface, chan->freq +
-						 j * secondary_channel * 20);
+			adj_chan = acs_find_chan(iface, chan->freq + (j * 20));
 			if (!adj_chan)
 				break;
 
@@ -934,14 +869,16 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 				break;
 			}
 
-			if (!acs_usable_chan(adj_chan))
-				continue;
-
-			factor += adj_chan->interference_factor;
-			total_weight += 1;
+			if (acs_usable_chan(adj_chan)) {
+				factor += adj_chan->interference_factor;
+				total_weight += 1;
+			} else {
+				update_best = false;
+			}
 
 			/* find the best channel in this segment */
-			if (!best || adj_chan->interference_factor <
+			if (update_best &&
+			    adj_chan->interference_factor <
 			    best->interference_factor)
 				best = adj_chan;
 		}
@@ -954,9 +891,8 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 
 		/* If the AP is in the 5 GHz or 6 GHz band, lets prefer a less
 		 * crowded primary channel if one was found in the segment */
-		if (iface->current_mode &&
-		    iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A &&
-		    best && chan != best) {
+		if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A &&
+		    chan != best) {
 			wpa_printf(MSG_DEBUG,
 				   "ACS: promoting channel %d over %d (less interference %Lg/%Lg)",
 				   best->chan, chan->chan,
@@ -969,9 +905,8 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 		 * channel interference factor. */
 		if (is_24ghz_mode(mode->mode)) {
 			for (j = 0; j < n_chans; j++) {
-				freq_offset = j * 20 * secondary_channel;
 				adj_chan = acs_find_chan(iface, chan->freq +
-							 freq_offset - 5);
+							 (j * 20) - 5);
 				if (adj_chan && acs_usable_chan(adj_chan)) {
 					factor += ACS_ADJ_WEIGHT *
 						adj_chan->interference_factor;
@@ -979,7 +914,7 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 				}
 
 				adj_chan = acs_find_chan(iface, chan->freq +
-							 freq_offset - 10);
+							 (j * 20) - 10);
 				if (adj_chan && acs_usable_chan(adj_chan)) {
 					factor += ACS_NEXT_ADJ_WEIGHT *
 						adj_chan->interference_factor;
@@ -987,7 +922,7 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 				}
 
 				adj_chan = acs_find_chan(iface, chan->freq +
-							 freq_offset + 5);
+							 (j * 20) + 5);
 				if (adj_chan && acs_usable_chan(adj_chan)) {
 					factor += ACS_ADJ_WEIGHT *
 						adj_chan->interference_factor;
@@ -995,7 +930,7 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 				}
 
 				adj_chan = acs_find_chan(iface, chan->freq +
-							 freq_offset + 10);
+							 (j * 20) + 10);
 				if (adj_chan && acs_usable_chan(adj_chan)) {
 					factor += ACS_NEXT_ADJ_WEIGHT *
 						adj_chan->interference_factor;
@@ -1004,9 +939,6 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 			}
 		}
 
-		if (total_weight == 0)
-			continue;
-
 		factor /= total_weight;
 
 		bias = NULL;
@@ -1044,7 +976,6 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 
 			*ideal_factor = factor;
 			*ideal_chan = chan;
-			ideal_bw320_offset = bw320_offset;
 
 #ifdef CONFIG_IEEE80211BE
 			if (iface->conf->ieee80211be)
@@ -1055,13 +986,9 @@ acs_find_ideal_chan_mode(struct hostapd_iface *iface,
 		}
 
 		/* This channel would at least be usable */
-		if (!(*rand_chan)) {
+		if (!(*rand_chan))
 			*rand_chan = chan;
-			ideal_bw320_offset = bw320_offset;
-		}
 	}
-
-	hostapd_set_and_check_bw320_offset(iface->conf, ideal_bw320_offset);
 }
 
 
@@ -1088,12 +1015,19 @@ acs_find_ideal_chan(struct hostapd_iface *iface)
 		goto bw_selected;
 	}
 
+	/* TODO: HT40- support */
+
+	if (iface->conf->ieee80211n &&
+	    iface->conf->secondary_channel == -1) {
+		wpa_printf(MSG_ERROR, "ACS: HT40- is not supported yet. Please try HT40+");
+		return NULL;
+	}
+
 	if (iface->conf->ieee80211n &&
 	    iface->conf->secondary_channel)
 		n_chans = 2;
 
-	if (iface->conf->ieee80211ac || iface->conf->ieee80211ax ||
-	    iface->conf->ieee80211be) {
+	if (iface->conf->ieee80211ac || iface->conf->ieee80211ax) {
 		switch (hostapd_get_oper_chwidth(iface->conf)) {
 		case CONF_OPER_CHWIDTH_80MHZ:
 			n_chans = 4;
@@ -1101,9 +1035,6 @@ acs_find_ideal_chan(struct hostapd_iface *iface)
 		case CONF_OPER_CHWIDTH_160MHZ:
 			n_chans = 8;
 			break;
-		case CONF_OPER_CHWIDTH_320MHZ:
-			n_chans = 16;
-			break;
 		default:
 			break;
 		}
@@ -1153,8 +1084,7 @@ static void acs_adjust_secondary(struct hostapd_iface *iface)
 	    acs_find_mode(iface, iface->freq) != HOSTAPD_MODE_IEEE80211A)
 		return;
 
-	wpa_printf(MSG_DEBUG,
-		   "ACS: Adjusting HT/VHT/HE/EHT secondary frequency");
+	wpa_printf(MSG_DEBUG, "ACS: Adjusting HT/VHT/HE secondary frequency");
 
 	for (i = 0; bw_desc[ACS_BW40][i].first != -1; i++) {
 		if (iface->freq == bw_desc[ACS_BW40][i].first)
@@ -1169,7 +1099,7 @@ static void acs_adjust_center_freq(struct hostapd_iface *iface)
 {
 	int center;
 
-	wpa_printf(MSG_DEBUG, "ACS: Adjusting center frequency");
+	wpa_printf(MSG_DEBUG, "ACS: Adjusting VHT center frequency");
 
 	switch (hostapd_get_oper_chwidth(iface->conf)) {
 	case CONF_OPER_CHWIDTH_USE_HT:
@@ -1187,29 +1117,12 @@ static void acs_adjust_center_freq(struct hostapd_iface *iface)
 		break;
 	case CONF_OPER_CHWIDTH_160MHZ:
 		center = acs_get_bw_center_chan(iface->freq, ACS_BW160);
-		break;
-	case CONF_OPER_CHWIDTH_320MHZ:
-		switch (hostapd_get_bw320_offset(iface->conf)) {
-		case 1:
-			center = acs_get_bw_center_chan(iface->freq,
-							ACS_BW320_1);
-			break;
-		case 2:
-			center = acs_get_bw_center_chan(iface->freq,
-							ACS_BW320_2);
-			break;
-		default:
-			wpa_printf(MSG_INFO,
-				   "ACS: BW320 offset is not selected");
-			return;
-		}
-
 		break;
 	default:
 		/* TODO: How can this be calculated? Adjust
 		 * acs_find_ideal_chan() */
 		wpa_printf(MSG_INFO,
-			   "ACS: Only VHT20/40/80/160/320 is supported now");
+			   "ACS: Only VHT20/40/80/160 is supported now");
 		return;
 	}
 
@@ -1272,8 +1185,7 @@ static void acs_study(struct hostapd_iface *iface)
 	iface->conf->punct_bitmap = ideal_chan->punct_bitmap;
 #endif /* CONFIG_IEEE80211BE */
 
-	if (iface->conf->ieee80211ac || iface->conf->ieee80211ax ||
-	    iface->conf->ieee80211be) {
+	if (iface->conf->ieee80211ac || iface->conf->ieee80211ax) {
 		acs_adjust_secondary(iface);
 		acs_adjust_center_freq(iface);
 	}
diff --git a/tests/hwsim/test_ap_acs.py b/tests/hwsim/test_ap_acs.py
index 001a5d4fd..e1359b6eb 100644
--- a/tests/hwsim/test_ap_acs.py
+++ b/tests/hwsim/test_ap_acs.py
@@ -205,20 +205,11 @@ def test_ap_acs_40mhz_minus(dev, apdev):
     params['acs_num_scans'] = '1'
     params['chanlist'] = '1 11'
     hapd = hostapd.add_ap(apdev[0], params, wait_enabled=False)
-    wait_acs(hapd)
-
-    freq = hapd.get_status_field("freq")
-    if int(freq) < 2400:
-        raise Exception("Unexpected frequency")
-    sec = hapd.get_status_field("secondary_channel")
-    if int(sec) != -1:
-        raise Exception("Unexpected secondary_channel: " + sec)
-
-    dev[0].connect("test-acs", psk="12345678", scan_freq=freq)
-    sig = dev[0].request("SIGNAL_POLL").splitlines()
-    logger.info("SIGNAL_POLL: " + str(sig))
-    if "WIDTH=40 MHz" not in sig:
-        raise Exception("Station did not report 40 MHz bandwidth")
+    ev = hapd.wait_event(["AP-ENABLED", "AP-DISABLED"], timeout=10)
+    if not ev:
+        raise Exception("ACS start timed out")
+    # HT40- is not currently supported in hostapd ACS, so do not try to connect
+    # or verify that this operation succeeded.
 
 def test_ap_acs_5ghz(dev, apdev):
     """Automatic channel selection on 5 GHz"""
-- 
2.39.2