recipes-wifi/hostapd/files/patches/mtk-0048-hostapd-mtk-add-support-for-channel-switching-with-c.patch

From 5d4d4397d0628a1aa83f83163e97ff34a0a5de43 Mon Sep 17 00:00:00 2001
From: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
Date: Thu, 16 Nov 2023 13:18:48 +0800
Subject: [PATCH] hostapd: mtk: add support for channel switching with csa sent
 when background radar is enabled

Signed-off-by: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
---
 hostapd/ctrl_iface.c   |  84 +++++++++++++++++-----
 src/ap/ctrl_iface_ap.c |   5 +-
 src/ap/dfs.c           | 156 +++++++++++++++++++++++++++++++++++------
 src/ap/dfs.h           |   9 ++-
 src/ap/hostapd.c       |   8 ++-
 5 files changed, 221 insertions(+), 41 deletions(-)

diff --git a/hostapd/ctrl_iface.c b/hostapd/ctrl_iface.c
index 96b593a..445cb34 100644
--- a/hostapd/ctrl_iface.c
+++ b/hostapd/ctrl_iface.c
@@ -2742,11 +2742,12 @@ static int hostapd_ctrl_iface_chan_switch(struct hostapd_iface *iface,
 					  char *pos)
 {
 #ifdef NEED_AP_MLME
-	struct csa_settings settings;
+	struct csa_settings settings, background_settings;
 	int ret;
-	int dfs_range = 0;
+	int freq, state;
 	unsigned int i;
-	int bandwidth;
+	int bandwidth, oper_chwidth;
+	bool background_radar, bw_changed, cac_required = false;
 
 	ret = hostapd_parse_csa_settings(pos, &settings);
 	if (ret)
@@ -2762,21 +2763,28 @@ static int hostapd_ctrl_iface_chan_switch(struct hostapd_iface *iface,
 	switch (settings.freq_params.bandwidth) {
 	case 40:
 		bandwidth = CHAN_WIDTH_40;
+		oper_chwidth = CONF_OPER_CHWIDTH_USE_HT;
 		break;
 	case 80:
-		if (settings.freq_params.center_freq2)
+		if (settings.freq_params.center_freq2) {
 			bandwidth = CHAN_WIDTH_80P80;
-		else
+			oper_chwidth = CONF_OPER_CHWIDTH_80P80MHZ;
+		} else {
 			bandwidth = CHAN_WIDTH_80;
+			oper_chwidth = CONF_OPER_CHWIDTH_80MHZ;
+		}
 		break;
 	case 160:
 		bandwidth = CHAN_WIDTH_160;
+		oper_chwidth = CONF_OPER_CHWIDTH_160MHZ;
 		break;
 	case 320:
 		bandwidth = CHAN_WIDTH_320;
+		oper_chwidth = CONF_OPER_CHWIDTH_320MHZ;
 		break;
 	default:
 		bandwidth = CHAN_WIDTH_20;
+		oper_chwidth = CONF_OPER_CHWIDTH_USE_HT;
 		break;
 	}
 
@@ -2797,19 +2805,29 @@ static int hostapd_ctrl_iface_chan_switch(struct hostapd_iface *iface,
 	}
 
 	if (settings.freq_params.center_freq1)
-		dfs_range += hostapd_is_dfs_overlap(
-			iface, bandwidth, settings.freq_params.center_freq1);
+		freq = settings.freq_params.center_freq1;
 	else
-		dfs_range += hostapd_is_dfs_overlap(
-			iface, bandwidth, settings.freq_params.freq);
-
-	if (settings.freq_params.center_freq2)
-		dfs_range += hostapd_is_dfs_overlap(
-			iface, bandwidth, settings.freq_params.center_freq2);
-
-	if (dfs_range) {
-		settings.cs_count = 5;
-		settings.block_tx = 1;
+		freq = settings.freq_params.freq;
+
+	bw_changed = oper_chwidth != hostapd_get_oper_chwidth(iface->conf);
+	state = hostapd_dfs_get_target_state(iface, bandwidth, freq,
+					     settings.freq_params.center_freq2);
+	switch (state) {
+	case HOSTAPD_CHAN_DFS_USABLE:
+		cac_required = true;
+		/* fallthrough */
+	case HOSTAPD_CHAN_DFS_AVAILABLE:
+		background_radar = hostapd_dfs_handle_csa(iface, &settings,
+							  &background_settings,
+							  cac_required,
+							  bw_changed);
+		break;
+	case HOSTAPD_CHAN_DFS_UNAVAILABLE:
+		wpa_printf(MSG_INFO,
+			   "chanswitch: target channel is UNAVAILABLE, so stop switching");
+		return -1;
+	default:
+		break;
 	}
 
 	for (i = 0; i < iface->num_bss; i++) {
@@ -2825,6 +2843,38 @@ static int hostapd_ctrl_iface_chan_switch(struct hostapd_iface *iface,
 			return ret;
 		}
 	}
+	/* Clear the CAC flag once all BSSes are switched to the new channel */
+	iface->cac_started = 0;
+
+	if (background_radar) {
+		u8 seg0, seg1;
+
+		ieee80211_freq_to_chan(background_settings.freq_params.center_freq1, &seg0);
+		ieee80211_freq_to_chan(background_settings.freq_params.center_freq2, &seg1);
+		ret = hostapd_start_dfs_cac(iface, iface->conf->hw_mode,
+					    background_settings.freq_params.freq,
+					    background_settings.freq_params.channel,
+					    background_settings.freq_params.ht_enabled,
+					    background_settings.freq_params.vht_enabled,
+					    background_settings.freq_params.he_enabled,
+					    background_settings.freq_params.eht_enabled,
+					    background_settings.freq_params.sec_channel_offset,
+					    oper_chwidth, seg0, seg1, true);
+		if (ret) {
+			wpa_printf(MSG_ERROR, "Background radar start dfs cac failed, %d",
+				   ret);
+			iface->radar_background.channel = -1;
+			return -1;
+		}
+
+		/* Cache background radar parameters. */
+		iface->radar_background.channel = background_settings.freq_params.channel;
+		iface->radar_background.secondary_channel =
+			background_settings.freq_params.sec_channel_offset;
+		iface->radar_background.freq = background_settings.freq_params.freq;
+		iface->radar_background.centr_freq_seg0_idx = seg0;
+		iface->radar_background.centr_freq_seg1_idx = seg1;
+	}
 
 	return 0;
 #else /* NEED_AP_MLME */
diff --git a/src/ap/ctrl_iface_ap.c b/src/ap/ctrl_iface_ap.c
index 86e8729..005c9fa 100644
--- a/src/ap/ctrl_iface_ap.c
+++ b/src/ap/ctrl_iface_ap.c
@@ -907,6 +907,7 @@ int hostapd_parse_csa_settings(const char *pos,
 			       struct csa_settings *settings)
 {
 	char *end;
+	int ret;
 
 	os_memset(settings, 0, sizeof(*settings));
 	settings->cs_count = strtol(pos, &end, 10);
@@ -916,7 +917,9 @@ int hostapd_parse_csa_settings(const char *pos,
 	}
 
 	settings->freq_params.freq = atoi(end);
-	if (settings->freq_params.freq == 0) {
+	ret = ieee80211_freq_to_chan(settings->freq_params.freq,
+				     &settings->freq_params.channel);
+	if (ret == NUM_HOSTAPD_MODES) {
 		wpa_printf(MSG_ERROR, "chanswitch: invalid freq provided");
 		return -1;
 	}
diff --git a/src/ap/dfs.c b/src/ap/dfs.c
index d490032..26ce229 100644
--- a/src/ap/dfs.c
+++ b/src/ap/dfs.c
@@ -248,14 +248,15 @@ static int is_in_chanlist(struct hostapd_iface *iface,
  */
 static int dfs_find_channel(struct hostapd_iface *iface,
 			    struct hostapd_channel_data **ret_chan,
-			    int idx, enum dfs_channel_type type)
+			    int n_chans, int idx, enum dfs_channel_type type)
 {
 	struct hostapd_hw_modes *mode;
 	struct hostapd_channel_data *chan;
-	int i, channel_idx = 0, n_chans, n_chans1;
+	int i, channel_idx = 0, n_chans1;
 
 	mode = iface->current_mode;
-	n_chans = dfs_get_used_n_chans(iface, &n_chans1);
+	if (!n_chans)
+		n_chans = dfs_get_used_n_chans(iface, &n_chans1);
 
 	wpa_printf(MSG_DEBUG, "DFS new chan checking %d channels", n_chans);
 	for (i = 0; i < mode->num_channels; i++) {
@@ -548,7 +549,7 @@ dfs_get_valid_channel(struct hostapd_iface *iface,
 		return NULL;
 
 	/* Get the count first */
-	num_available_chandefs = dfs_find_channel(iface, NULL, 0, type);
+	num_available_chandefs = dfs_find_channel(iface, NULL, 0, 0, type);
 	wpa_printf(MSG_DEBUG, "DFS: num_available_chandefs=%d",
 		   num_available_chandefs);
 	if (num_available_chandefs == 0)
@@ -569,7 +570,7 @@ dfs_get_valid_channel(struct hostapd_iface *iface,
 		return NULL;
 
 	chan_idx = _rand % num_available_chandefs;
-	dfs_find_channel(iface, &chan, chan_idx, type);
+	dfs_find_channel(iface, &chan, 0, chan_idx, type);
 	if (!chan) {
 		wpa_printf(MSG_DEBUG, "DFS: no random channel found");
 		return NULL;
@@ -599,7 +600,7 @@ dfs_get_valid_channel(struct hostapd_iface *iface,
 		for (i = 0; i < num_available_chandefs - 1; i++) {
 			/* start from chan_idx + 1, end when chan_idx - 1 */
 			chan_idx2 = (chan_idx + 1 + i) % num_available_chandefs;
-			dfs_find_channel(iface, &chan2, chan_idx2, type);
+			dfs_find_channel(iface, &chan2, 0, chan_idx2, type);
 			if (chan2 && abs(chan2->chan - chan->chan) > 12) {
 				/* two channels are not adjacent */
 				sec_chan_idx_80p80 = chan2->chan;
@@ -1304,6 +1305,9 @@ int hostapd_dfs_pre_cac_expired(struct hostapd_iface *iface, int freq,
 	set_dfs_state(iface, freq, ht_enabled, chan_offset, chan_width,
 		      cf1, cf2, HOSTAPD_CHAN_DFS_USABLE);
 
+	if (dfs_use_radar_background(iface) && iface->radar_background.channel == -1)
+		hostpad_dfs_update_background_chain(iface);
+
 	return 0;
 }
 
@@ -1717,14 +1721,15 @@ int hostapd_handle_dfs_offload(struct hostapd_iface *iface)
 }
 
 
-int hostapd_is_dfs_overlap(struct hostapd_iface *iface, enum chan_width width,
-			   int center_freq)
+int hostapd_dfs_get_target_state(struct hostapd_iface *iface, enum chan_width width,
+				 int center_freq, int center_freq2)
 {
 	struct hostapd_channel_data *chan;
 	struct hostapd_hw_modes *mode = iface->current_mode;
-	int half_width;
-	int res = 0;
+	int half_width, chan_state, state = 0;
+	int upper, lower;
 	int i;
+	bool in_range;
 
 	if (!iface->conf->ieee80211h || !mode ||
 	    mode->mode != HOSTAPD_MODE_IEEE80211A)
@@ -1757,18 +1762,129 @@ int hostapd_is_dfs_overlap(struct hostapd_iface *iface, enum chan_width width,
 		if (!(chan->flag & HOSTAPD_CHAN_RADAR))
 			continue;
 
-		if ((chan->flag & HOSTAPD_CHAN_DFS_MASK) ==
-		    HOSTAPD_CHAN_DFS_AVAILABLE)
-			continue;
+		upper = chan->freq + half_width;
+		lower = chan->freq - half_width;
+		in_range = (lower < center_freq && center_freq < upper) ||
+			   (center_freq2 && (lower < center_freq2 && center_freq2 < upper));
+		if (in_range) {
+			chan_state = chan->flag & HOSTAPD_CHAN_DFS_MASK;
+			switch (chan_state) {
+			case HOSTAPD_CHAN_DFS_USABLE:
+				state = HOSTAPD_CHAN_DFS_USABLE;
+				break;
+			case HOSTAPD_CHAN_DFS_AVAILABLE:
+				if (state != HOSTAPD_CHAN_DFS_USABLE)
+					state = HOSTAPD_CHAN_DFS_AVAILABLE;
+				break;
+			case HOSTAPD_CHAN_DFS_UNKNOWN:
+				wpa_printf(MSG_WARNING, "chan %d DFS state: UNKNOWN",
+					   chan->freq);
+				/* fallthrough */
+			case HOSTAPD_CHAN_DFS_UNAVAILABLE:
+			default:
+				return HOSTAPD_CHAN_DFS_UNAVAILABLE;
+			}
+		}
+	}
 
-		if (center_freq - chan->freq < half_width &&
-		    chan->freq - center_freq < half_width)
-			res++;
+	wpa_printf(MSG_DEBUG, "freq range (%d, %d) has DFS state %d",
+		   center_freq - half_width, center_freq + half_width, state);
+
+	return state;
+}
+
+
+static struct hostapd_channel_data *
+dfs_get_csa_channel(struct hostapd_iface *iface,
+		    int n_chans, int cur_center,
+		    enum dfs_channel_type type)
+{
+	struct hostapd_channel_data *chan;
+	int avail_chan_num;
+	u32 _rand, idx;
+
+	if (os_get_random((u8 *)&_rand, sizeof(_rand)) < 0)
+		return NULL;
+
+	avail_chan_num = dfs_find_channel(iface, NULL, n_chans, 0, type);
+	if (!avail_chan_num)
+		return NULL;
+
+	idx = _rand % avail_chan_num;
+	dfs_find_channel(iface, &chan, n_chans, idx, type);
+	if (cur_center == chan->freq + (n_chans - 1) * 10) {
+		if (avail_chan_num == 1)
+			return NULL;
+
+		/* Get the next channel if the found channel is same as current channel */
+		idx = (idx + 1) % avail_chan_num;
+		dfs_find_channel(iface, &chan, n_chans, idx, type);
 	}
 
-	wpa_printf(MSG_DEBUG, "DFS CAC required: (%d, %d): in range: %s",
-		   center_freq - half_width, center_freq + half_width,
-		   res ? "yes" : "no");
+	return chan;
+}
 
-	return res;
+
+/*
+ * DFS handler for CSA
+ * 1  - update background radar with the filled setting
+ * 0  - background radar is not enabled / background radar remain at the same channel /
+ *	disable background radar
+ */
+int hostapd_dfs_handle_csa(struct hostapd_iface *iface,
+			   struct csa_settings *settings,
+			   struct csa_settings *background_settings,
+			   bool cac_required, bool bw_changed)
+{
+	struct hostapd_channel_data *chan;
+	struct hostapd_freq_params *freq_params = &settings->freq_params;
+	int center = settings->freq_params.center_freq1;
+	int background_center = 5000 + iface->radar_background.centr_freq_seg0_idx * 5;
+	int n_chans = settings->freq_params.bandwidth / 20;
+	bool update_background = false;
+
+	if (!dfs_use_radar_background(iface)) {
+		settings->cs_count = 5;
+		settings->block_tx = cac_required;
+		return 0;
+	}
+
+	if (!cac_required) {
+		if (!bw_changed && center != background_center)
+			return 0;
+		/* Update background radar due to bw change or channel overlapping */
+		update_background = true;
+	} else {
+		/*
+		* Get available channel for main channel.
+		* If no available channel for main channel, then perform
+		* the CAC of target channel on the main channel, and select
+		* an usable channel for background radar.
+		*/
+		iface->radar_background.temp_ch = 1;
+		chan = dfs_get_csa_channel(iface, n_chans, 0, DFS_AVAILABLE);
+		if (!chan)
+			update_background = true;
+	}
+
+	if (update_background) {
+		chan = dfs_get_csa_channel(iface, n_chans, center, DFS_NO_CAC_YET);
+		if (!chan)
+			goto bkg_disable;
+		freq_params = &background_settings->freq_params;
+		iface->radar_background.temp_ch = 0;
+	}
+
+	memcpy(background_settings, settings, sizeof(*settings));
+	freq_params->freq = chan->freq;
+	freq_params->channel = chan->chan;
+	freq_params->sec_channel_offset = 1;
+	freq_params->center_freq1 = chan->freq + (n_chans - 1) * 10;
+	freq_params->center_freq2 = 0;
+
+	return 1;
+
+bkg_disable:
+	iface->radar_background.channel = -1;
+	return 0;
 }
diff --git a/src/ap/dfs.h b/src/ap/dfs.h
index 1a0791f..0a7c25d 100644
--- a/src/ap/dfs.h
+++ b/src/ap/dfs.h
@@ -33,7 +33,12 @@ int hostapd_dfs_start_cac(struct hostapd_iface *iface, int freq,
 			  int ht_enabled, int chan_offset, int chan_width,
 			  int cf1, int cf2);
 int hostapd_handle_dfs_offload(struct hostapd_iface *iface);
-int hostapd_is_dfs_overlap(struct hostapd_iface *iface, enum chan_width width,
-			   int center_freq);
+int hostapd_dfs_get_target_state(struct hostapd_iface *iface, enum chan_width width,
+				 int center_freq, int center_freq2);
+int hostapd_dfs_handle_csa(struct hostapd_iface *iface,
+			   struct csa_settings *settings,
+			   struct csa_settings *background_settings,
+			   bool cac_required, bool bw_changed);
+
 
 #endif /* DFS_H */
diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index 250c168..d983902 100644
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -3708,7 +3708,13 @@ static int hostapd_fill_csa_settings(struct hostapd_data *hapd,
 	u8 chan, bandwidth;
 
 	os_memset(&old_freq, 0, sizeof(old_freq));
-	if (!iface || !iface->freq || hapd->csa_in_progress)
+	if (!iface || !iface->freq)
+		return -1;
+
+	/* Allow another channel switch if the previous
+	 * channel switch is waiting for post-CSA radar detection
+	 */
+	if (hapd->csa_in_progress && !iface->cac_started)
 		return -1;
 
 	switch (settings->freq_params.bandwidth) {
-- 
2.18.0