ASR_BASE

Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/package/kernel/asr-wl/asr-hostapd/asr-hostapd-2023-06-22/src/ap/dfs.c b/package/kernel/asr-wl/asr-hostapd/asr-hostapd-2023-06-22/src/ap/dfs.c
new file mode 100644
index 0000000..d1786ee
--- /dev/null
+++ b/package/kernel/asr-wl/asr-hostapd/asr-hostapd-2023-06-22/src/ap/dfs.c
@@ -0,0 +1,1669 @@
+/*
+ * DFS - Dynamic Frequency Selection
+ * Copyright (c) 2002-2013, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2013-2017, Qualcomm Atheros, Inc.
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "utils/includes.h"
+
+#include "utils/common.h"
+#include "common/ieee802_11_defs.h"
+#include "common/hw_features_common.h"
+#include "common/wpa_ctrl.h"
+#include "hostapd.h"
+#include "ap_drv_ops.h"
+#include "drivers/driver.h"
+#include "dfs.h"
+#include "crypto/crypto.h"
+
+
+enum dfs_channel_type {
+	DFS_ANY_CHANNEL,
+	DFS_AVAILABLE, /* non-radar or radar-available */
+	DFS_NO_CAC_YET, /* radar-not-yet-available */
+};
+
+static struct hostapd_channel_data *
+dfs_downgrade_bandwidth(struct hostapd_iface *iface, int *secondary_channel,
+			u8 *oper_centr_freq_seg0_idx,
+			u8 *oper_centr_freq_seg1_idx,
+			enum dfs_channel_type *channel_type);
+
+
+static bool dfs_use_radar_background(struct hostapd_iface *iface)
+{
+	return (iface->drv_flags2 & WPA_DRIVER_RADAR_BACKGROUND) &&
+		iface->conf->enable_background_radar;
+}
+
+
+static int dfs_get_used_n_chans(struct hostapd_iface *iface, int *seg1)
+{
+	int n_chans = 1;
+
+	*seg1 = 0;
+
+	if (iface->conf->ieee80211n && iface->conf->secondary_channel)
+		n_chans = 2;
+
+	if (iface->conf->ieee80211ac || iface->conf->ieee80211ax) {
+		switch (hostapd_get_oper_chwidth(iface->conf)) {
+		case CONF_OPER_CHWIDTH_USE_HT:
+			break;
+		case CONF_OPER_CHWIDTH_80MHZ:
+			n_chans = 4;
+			break;
+		case CONF_OPER_CHWIDTH_160MHZ:
+			n_chans = 8;
+			break;
+		case CONF_OPER_CHWIDTH_80P80MHZ:
+			n_chans = 4;
+			*seg1 = 4;
+			break;
+		default:
+			break;
+		}
+	}
+
+	return n_chans;
+}
+
+
+/* dfs_channel_available: select new channel according to type parameter */
+static int dfs_channel_available(struct hostapd_channel_data *chan,
+				 enum dfs_channel_type type)
+{
+	if (type == DFS_NO_CAC_YET) {
+		/* Select only radar channel where CAC has not been
+		 * performed yet
+		 */
+		if ((chan->flag & HOSTAPD_CHAN_RADAR) &&
+		    (chan->flag & HOSTAPD_CHAN_DFS_MASK) ==
+		     HOSTAPD_CHAN_DFS_USABLE)
+			return 1;
+		return 0;
+	}
+
+	/*
+	 * When radar detection happens, CSA is performed. However, there's no
+	 * time for CAC, so radar channels must be skipped when finding a new
+	 * channel for CSA, unless they are available for immediate use.
+	 */
+	if (type == DFS_AVAILABLE && (chan->flag & HOSTAPD_CHAN_RADAR) &&
+	    ((chan->flag & HOSTAPD_CHAN_DFS_MASK) !=
+	     HOSTAPD_CHAN_DFS_AVAILABLE))
+		return 0;
+
+	if (chan->flag & HOSTAPD_CHAN_DISABLED)
+		return 0;
+	if ((chan->flag & HOSTAPD_CHAN_RADAR) &&
+	    ((chan->flag & HOSTAPD_CHAN_DFS_MASK) ==
+	     HOSTAPD_CHAN_DFS_UNAVAILABLE))
+		return 0;
+	return 1;
+}
+
+
+static int dfs_is_chan_allowed(struct hostapd_channel_data *chan, int n_chans)
+{
+	/*
+	 * The tables contain first valid channel number based on channel width.
+	 * We will also choose this first channel as the control one.
+	 */
+	int allowed_40[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149, 157,
+			     165, 173, 184, 192 };
+	/*
+	 * VHT80, valid channels based on center frequency:
+	 * 42, 58, 106, 122, 138, 155, 171
+	 */
+	int allowed_80[] = { 36, 52, 100, 116, 132, 149, 165 };
+	/*
+	 * VHT160 valid channels based on center frequency:
+	 * 50, 114, 163
+	 */
+	int allowed_160[] = { 36, 100, 149 };
+	int *allowed = allowed_40;
+	unsigned int i, allowed_no = 0;
+
+	switch (n_chans) {
+	case 2:
+		allowed = allowed_40;
+		allowed_no = ARRAY_SIZE(allowed_40);
+		break;
+	case 4:
+		allowed = allowed_80;
+		allowed_no = ARRAY_SIZE(allowed_80);
+		break;
+	case 8:
+		allowed = allowed_160;
+		allowed_no = ARRAY_SIZE(allowed_160);
+		break;
+	default:
+		wpa_printf(MSG_DEBUG, "Unknown width for %d channels", n_chans);
+		break;
+	}
+
+	for (i = 0; i < allowed_no; i++) {
+		if (chan->chan == allowed[i])
+			return 1;
+	}
+
+	return 0;
+}
+
+
+static struct hostapd_channel_data *
+dfs_get_chan_data(struct hostapd_hw_modes *mode, int freq, int first_chan_idx)
+{
+	int i;
+
+	for (i = first_chan_idx; i < mode->num_channels; i++) {
+		if (mode->channels[i].freq == freq)
+			return &mode->channels[i];
+	}
+
+	return NULL;
+}
+
+
+static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
+				    int first_chan_idx, int num_chans,
+				    enum dfs_channel_type type)
+{
+	struct hostapd_channel_data *first_chan, *chan;
+	int i;
+	u32 bw = num_chan_to_bw(num_chans);
+
+	if (first_chan_idx + num_chans > mode->num_channels) {
+		wpa_printf(MSG_DEBUG,
+			   "DFS: some channels in range not defined");
+		return 0;
+	}
+
+	first_chan = &mode->channels[first_chan_idx];
+
+	/* hostapd DFS implementation assumes the first channel as primary.
+	 * If it's not allowed to use the first channel as primary, decline the
+	 * whole channel range. */
+	if (!chan_pri_allowed(first_chan)) {
+		wpa_printf(MSG_DEBUG, "DFS: primary chanenl not allowed");
+		return 0;
+	}
+
+	for (i = 0; i < num_chans; i++) {
+		chan = dfs_get_chan_data(mode, first_chan->freq + i * 20,
+					 first_chan_idx);
+		if (!chan) {
+			wpa_printf(MSG_DEBUG, "DFS: no channel data for %d",
+				   first_chan->freq + i * 20);
+			return 0;
+		}
+
+		/* HT 40 MHz secondary channel availability checked only for
+		 * primary channel */
+		if (!chan_bw_allowed(chan, bw, 1, !i)) {
+			wpa_printf(MSG_DEBUG, "DFS: bw now allowed for %d",
+				   first_chan->freq + i * 20);
+			return 0;
+		}
+
+		if (!dfs_channel_available(chan, type)) {
+			wpa_printf(MSG_DEBUG, "DFS: channel not available %d",
+				   first_chan->freq + i * 20);
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
+
+static int is_in_chanlist(struct hostapd_iface *iface,
+			  struct hostapd_channel_data *chan)
+{
+	if (!iface->conf->acs_ch_list.num)
+		return 1;
+
+	return freq_range_list_includes(&iface->conf->acs_ch_list, chan->chan);
+}
+
+
+/*
+ * The function assumes HT40+ operation.
+ * Make sure to adjust the following variables after calling this:
+ *  - hapd->secondary_channel
+ *  - hapd->vht/he_oper_centr_freq_seg0_idx
+ *  - hapd->vht/he_oper_centr_freq_seg1_idx
+ */
+static int dfs_find_channel(struct hostapd_iface *iface,
+			    struct hostapd_channel_data **ret_chan,
+			    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;
+
+	mode = iface->current_mode;
+	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++) {
+		chan = &mode->channels[i];
+
+		/* Skip HT40/VHT incompatible channels */
+		if (iface->conf->ieee80211n &&
+		    iface->conf->secondary_channel &&
+		    (!dfs_is_chan_allowed(chan, n_chans) ||
+		     !(chan->allowed_bw & HOSTAPD_CHAN_WIDTH_40P))) {
+			wpa_printf(MSG_DEBUG,
+				   "DFS: channel %d (%d) is incompatible",
+				   chan->freq, chan->chan);
+			continue;
+		}
+
+		/* Skip incompatible chandefs */
+		if (!dfs_chan_range_available(mode, i, n_chans, type)) {
+			wpa_printf(MSG_DEBUG,
+				   "DFS: range not available for %d (%d)",
+				   chan->freq, chan->chan);
+			continue;
+		}
+
+		if (!is_in_chanlist(iface, chan)) {
+			wpa_printf(MSG_DEBUG,
+				   "DFS: channel %d (%d) not in chanlist",
+				   chan->freq, chan->chan);
+			continue;
+		}
+
+		if (chan->max_tx_power < iface->conf->min_tx_power)
+			continue;
+
+		if ((chan->flag & HOSTAPD_CHAN_INDOOR_ONLY) &&
+		    iface->conf->country[2] == 0x4f)
+			continue;
+
+		if (ret_chan && idx == channel_idx) {
+			wpa_printf(MSG_DEBUG, "Selected channel %d (%d)",
+				   chan->freq, chan->chan);
+			*ret_chan = chan;
+			return idx;
+		}
+		wpa_printf(MSG_DEBUG, "Adding channel %d (%d)",
+			   chan->freq, chan->chan);
+		channel_idx++;
+	}
+	return channel_idx;
+}
+
+
+static void dfs_adjust_center_freq(struct hostapd_iface *iface,
+				   struct hostapd_channel_data *chan,
+				   int secondary_channel,
+				   int sec_chan_idx_80p80,
+				   u8 *oper_centr_freq_seg0_idx,
+				   u8 *oper_centr_freq_seg1_idx)
+{
+	if (!iface->conf->ieee80211ac && !iface->conf->ieee80211ax)
+		return;
+
+	if (!chan)
+		return;
+
+	*oper_centr_freq_seg1_idx = 0;
+
+	switch (hostapd_get_oper_chwidth(iface->conf)) {
+	case CONF_OPER_CHWIDTH_USE_HT:
+		if (secondary_channel == 1)
+			*oper_centr_freq_seg0_idx = chan->chan + 2;
+		else if (secondary_channel == -1)
+			*oper_centr_freq_seg0_idx = chan->chan - 2;
+		else
+			*oper_centr_freq_seg0_idx = chan->chan;
+		break;
+	case CONF_OPER_CHWIDTH_80MHZ:
+		*oper_centr_freq_seg0_idx = chan->chan + 6;
+		break;
+	case CONF_OPER_CHWIDTH_160MHZ:
+		*oper_centr_freq_seg0_idx = chan->chan + 14;
+		break;
+	case CONF_OPER_CHWIDTH_80P80MHZ:
+		*oper_centr_freq_seg0_idx = chan->chan + 6;
+		*oper_centr_freq_seg1_idx = sec_chan_idx_80p80 + 6;
+		break;
+
+	default:
+		wpa_printf(MSG_INFO,
+			   "DFS: Unsupported channel width configuration");
+		*oper_centr_freq_seg0_idx = 0;
+		break;
+	}
+
+	wpa_printf(MSG_DEBUG, "DFS adjusting VHT center frequency: %d, %d",
+		   *oper_centr_freq_seg0_idx,
+		   *oper_centr_freq_seg1_idx);
+}
+
+
+/* Return start channel idx we will use for mode->channels[idx] */
+static int dfs_get_start_chan_idx(struct hostapd_iface *iface, int *seg1_start)
+{
+	struct hostapd_hw_modes *mode;
+	struct hostapd_channel_data *chan;
+	int channel_no = iface->conf->channel;
+	int res = -1, i;
+	int chan_seg1 = -1;
+
+	*seg1_start = -1;
+
+	/* HT40- */
+	if (iface->conf->ieee80211n && iface->conf->secondary_channel == -1)
+		channel_no -= 4;
+
+	/* VHT/HE */
+	if (iface->conf->ieee80211ac || iface->conf->ieee80211ax) {
+		switch (hostapd_get_oper_chwidth(iface->conf)) {
+		case CONF_OPER_CHWIDTH_USE_HT:
+			break;
+		case CONF_OPER_CHWIDTH_80MHZ:
+			channel_no = hostapd_get_oper_centr_freq_seg0_idx(
+				iface->conf) - 6;
+			break;
+		case CONF_OPER_CHWIDTH_160MHZ:
+			channel_no = hostapd_get_oper_centr_freq_seg0_idx(
+				iface->conf) - 14;
+			break;
+		case CONF_OPER_CHWIDTH_80P80MHZ:
+			channel_no = hostapd_get_oper_centr_freq_seg0_idx(
+				iface->conf) - 6;
+			chan_seg1 = hostapd_get_oper_centr_freq_seg1_idx(
+				iface->conf) - 6;
+			break;
+		default:
+			wpa_printf(MSG_INFO,
+				   "DFS only VHT20/40/80/160/80+80 is supported now");
+			channel_no = -1;
+			break;
+		}
+	}
+
+	/* Get idx */
+	mode = iface->current_mode;
+	for (i = 0; i < mode->num_channels; i++) {
+		chan = &mode->channels[i];
+		if (chan->chan == channel_no) {
+			res = i;
+			break;
+		}
+	}
+
+	if (res != -1 && chan_seg1 > -1) {
+		int found = 0;
+
+		/* Get idx for seg1 */
+		mode = iface->current_mode;
+		for (i = 0; i < mode->num_channels; i++) {
+			chan = &mode->channels[i];
+			if (chan->chan == chan_seg1) {
+				*seg1_start = i;
+				found = 1;
+				break;
+			}
+		}
+		if (!found)
+			res = -1;
+	}
+
+	if (res == -1) {
+		wpa_printf(MSG_DEBUG,
+			   "DFS chan_idx seems wrong; num-ch: %d ch-no: %d conf-ch-no: %d 11n: %d sec-ch: %d vht-oper-width: %d",
+			   mode->num_channels, channel_no, iface->conf->channel,
+			   iface->conf->ieee80211n,
+			   iface->conf->secondary_channel,
+			   hostapd_get_oper_chwidth(iface->conf));
+
+		for (i = 0; i < mode->num_channels; i++) {
+			wpa_printf(MSG_DEBUG, "Available channel: %d",
+				   mode->channels[i].chan);
+		}
+	}
+
+	return res;
+}
+
+
+/* At least one channel have radar flag */
+static int dfs_check_chans_radar(struct hostapd_iface *iface,
+				 int start_chan_idx, int n_chans)
+{
+	struct hostapd_channel_data *channel;
+	struct hostapd_hw_modes *mode;
+	int i, res = 0;
+
+	mode = iface->current_mode;
+
+	for (i = 0; i < n_chans; i++) {
+		if (start_chan_idx + i >= mode->num_channels)
+			break;
+		channel = &mode->channels[start_chan_idx + i];
+		if (channel->flag & HOSTAPD_CHAN_RADAR)
+			res++;
+	}
+
+	return res;
+}
+
+
+/* All channels available */
+static int dfs_check_chans_available(struct hostapd_iface *iface,
+				     int start_chan_idx, int n_chans)
+{
+	struct hostapd_channel_data *channel;
+	struct hostapd_hw_modes *mode;
+	int i;
+
+	mode = iface->current_mode;
+
+	for (i = 0; i < n_chans; i++) {
+		channel = &mode->channels[start_chan_idx + i];
+
+		if (channel->flag & HOSTAPD_CHAN_DISABLED)
+			break;
+
+		if (!(channel->flag & HOSTAPD_CHAN_RADAR))
+			continue;
+
+		if ((channel->flag & HOSTAPD_CHAN_DFS_MASK) !=
+		    HOSTAPD_CHAN_DFS_AVAILABLE)
+			break;
+	}
+
+	return i == n_chans;
+}
+
+
+/* At least one channel unavailable */
+static int dfs_check_chans_unavailable(struct hostapd_iface *iface,
+				       int start_chan_idx,
+				       int n_chans)
+{
+	struct hostapd_channel_data *channel;
+	struct hostapd_hw_modes *mode;
+	int i, res = 0;
+
+	mode = iface->current_mode;
+
+	for (i = 0; i < n_chans; i++) {
+		channel = &mode->channels[start_chan_idx + i];
+		if (channel->flag & HOSTAPD_CHAN_DISABLED)
+			res++;
+		if ((channel->flag & HOSTAPD_CHAN_DFS_MASK) ==
+		    HOSTAPD_CHAN_DFS_UNAVAILABLE)
+			res++;
+	}
+
+	return res;
+}
+
+
+static struct hostapd_channel_data *
+dfs_get_valid_channel(struct hostapd_iface *iface,
+		      int *secondary_channel,
+		      u8 *oper_centr_freq_seg0_idx,
+		      u8 *oper_centr_freq_seg1_idx,
+		      enum dfs_channel_type type)
+{
+	struct hostapd_hw_modes *mode;
+	struct hostapd_channel_data *chan = NULL;
+	struct hostapd_channel_data *chan2 = NULL;
+	int num_available_chandefs;
+	int chan_idx, chan_idx2;
+	int sec_chan_idx_80p80 = -1;
+	bool is_mesh = false;
+	int i;
+	u32 _rand;
+
+#ifdef CONFIG_MESH
+	is_mesh = iface->mconf;
+#endif
+
+	wpa_printf(MSG_DEBUG, "DFS: Selecting random channel");
+	*secondary_channel = 0;
+	*oper_centr_freq_seg0_idx = 0;
+	*oper_centr_freq_seg1_idx = 0;
+
+	if (iface->current_mode == NULL)
+		return NULL;
+
+	mode = iface->current_mode;
+	if (mode->mode != HOSTAPD_MODE_IEEE80211A)
+		return NULL;
+
+	/* Get the count first */
+	num_available_chandefs = dfs_find_channel(iface, NULL, 0, type);
+	wpa_printf(MSG_DEBUG, "DFS: num_available_chandefs=%d",
+		   num_available_chandefs);
+	if (num_available_chandefs == 0)
+		return NULL;
+
+	/* try to use deterministic channel in mesh, so that both sides
+	 * have a chance to switch to the same channel */
+	if (is_mesh) {
+#ifdef CONFIG_MESH
+		u64 hash[4];
+		const u8 *meshid[1] = { &iface->mconf->meshid[0] };
+		const size_t meshid_len = iface->mconf->meshid_len;
+
+		sha256_vector(1, meshid, &meshid_len, (u8 *)&hash[0]);
+		_rand = hash[0] + hash[1] + hash[2] + hash[3];
+#endif
+	} else if (os_get_random((u8 *) &_rand, sizeof(_rand)) < 0)
+		return NULL;
+
+	chan_idx = _rand % num_available_chandefs;
+	dfs_find_channel(iface, &chan, chan_idx, type);
+	if (!chan) {
+		wpa_printf(MSG_DEBUG, "DFS: no random channel found");
+		return NULL;
+	}
+	wpa_printf(MSG_DEBUG, "DFS: got random channel %d (%d)",
+		   chan->freq, chan->chan);
+
+	/* dfs_find_channel() calculations assume HT40+ */
+	if (iface->conf->secondary_channel)
+		*secondary_channel = 1;
+	else
+		*secondary_channel = 0;
+
+	/* Get secondary channel for HT80P80 */
+	if (hostapd_get_oper_chwidth(iface->conf) ==
+	    CONF_OPER_CHWIDTH_80P80MHZ) {
+		if (num_available_chandefs <= 1) {
+			wpa_printf(MSG_ERROR,
+				   "only 1 valid chan, can't support 80+80");
+			return NULL;
+		}
+
+		/*
+		 * Loop all channels except channel1 to find a valid channel2
+		 * that is not adjacent to channel1.
+		 */
+		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);
+			if (chan2 && abs(chan2->chan - chan->chan) > 12) {
+				/* two channels are not adjacent */
+				sec_chan_idx_80p80 = chan2->chan;
+				wpa_printf(MSG_DEBUG,
+					   "DFS: got second chan: %d (%d)",
+					   chan2->freq, chan2->chan);
+				break;
+			}
+		}
+
+		/* Check if we got a valid secondary channel which is not
+		 * adjacent to the first channel.
+		 */
+		if (sec_chan_idx_80p80 == -1) {
+			wpa_printf(MSG_INFO,
+				   "DFS: failed to get chan2 for 80+80");
+			return NULL;
+		}
+	}
+
+	dfs_adjust_center_freq(iface, chan,
+			       *secondary_channel,
+			       sec_chan_idx_80p80,
+			       oper_centr_freq_seg0_idx,
+			       oper_centr_freq_seg1_idx);
+
+	return chan;
+}
+
+
+static int dfs_set_valid_channel(struct hostapd_iface *iface, int skip_radar)
+{
+	struct hostapd_channel_data *channel;
+	u8 cf1 = 0, cf2 = 0;
+	int sec = 0;
+
+	channel = dfs_get_valid_channel(iface, &sec, &cf1, &cf2,
+					skip_radar ? DFS_AVAILABLE :
+					DFS_ANY_CHANNEL);
+	if (!channel) {
+		wpa_printf(MSG_ERROR, "could not get valid channel");
+		return -1;
+	}
+
+	iface->freq = channel->freq;
+	iface->conf->channel = channel->chan;
+	iface->conf->secondary_channel = sec;
+	hostapd_set_oper_centr_freq_seg0_idx(iface->conf, cf1);
+	hostapd_set_oper_centr_freq_seg1_idx(iface->conf, cf2);
+
+	return 0;
+}
+
+
+static int set_dfs_state_freq(struct hostapd_iface *iface, int freq, u32 state)
+{
+	struct hostapd_hw_modes *mode;
+	struct hostapd_channel_data *chan = NULL;
+	int i;
+
+	mode = iface->current_mode;
+	if (mode == NULL)
+		return 0;
+
+	wpa_printf(MSG_DEBUG, "set_dfs_state 0x%X for %d MHz", state, freq);
+	for (i = 0; i < iface->current_mode->num_channels; i++) {
+		chan = &iface->current_mode->channels[i];
+		if (chan->freq == freq) {
+			if (chan->flag & HOSTAPD_CHAN_RADAR) {
+				chan->flag &= ~HOSTAPD_CHAN_DFS_MASK;
+				chan->flag |= state;
+				return 1; /* Channel found */
+			}
+		}
+	}
+	wpa_printf(MSG_WARNING, "Can't set DFS state for freq %d MHz", freq);
+	return 0;
+}
+
+
+static int set_dfs_state(struct hostapd_iface *iface, int freq, int ht_enabled,
+			 int chan_offset, int chan_width, int cf1,
+			 int cf2, u32 state)
+{
+	int n_chans = 1, i;
+	struct hostapd_hw_modes *mode;
+	int frequency = freq;
+	int frequency2 = 0;
+	int ret = 0;
+
+	mode = iface->current_mode;
+	if (mode == NULL)
+		return 0;
+
+	if (mode->mode != HOSTAPD_MODE_IEEE80211A) {
+		wpa_printf(MSG_WARNING, "current_mode != IEEE80211A");
+		return 0;
+	}
+
+	/* Seems cf1 and chan_width is enough here */
+	switch (chan_width) {
+	case CHAN_WIDTH_20_NOHT:
+	case CHAN_WIDTH_20:
+		n_chans = 1;
+		if (frequency == 0)
+			frequency = cf1;
+		break;
+	case CHAN_WIDTH_40:
+		n_chans = 2;
+		frequency = cf1 - 10;
+		break;
+	case CHAN_WIDTH_80:
+		n_chans = 4;
+		frequency = cf1 - 30;
+		break;
+	case CHAN_WIDTH_80P80:
+		n_chans = 4;
+		frequency = cf1 - 30;
+		frequency2 = cf2 - 30;
+		break;
+	case CHAN_WIDTH_160:
+		n_chans = 8;
+		frequency = cf1 - 70;
+		break;
+	default:
+		wpa_printf(MSG_INFO, "DFS chan_width %d not supported",
+			   chan_width);
+		break;
+	}
+
+	wpa_printf(MSG_DEBUG, "DFS freq: %dMHz, n_chans: %d", frequency,
+		   n_chans);
+	for (i = 0; i < n_chans; i++) {
+		ret += set_dfs_state_freq(iface, frequency, state);
+		frequency = frequency + 20;
+
+		if (chan_width == CHAN_WIDTH_80P80) {
+			ret += set_dfs_state_freq(iface, frequency2, state);
+			frequency2 = frequency2 + 20;
+		}
+	}
+
+	return ret;
+}
+
+
+static int dfs_are_channels_overlapped(struct hostapd_iface *iface, int freq,
+				       int chan_width, int cf1, int cf2)
+{
+	int start_chan_idx, start_chan_idx1;
+	struct hostapd_hw_modes *mode;
+	struct hostapd_channel_data *chan;
+	int n_chans, n_chans1, i, j, frequency = freq, radar_n_chans = 1;
+	u8 radar_chan;
+	int res = 0;
+
+	/* Our configuration */
+	mode = iface->current_mode;
+	start_chan_idx = dfs_get_start_chan_idx(iface, &start_chan_idx1);
+	n_chans = dfs_get_used_n_chans(iface, &n_chans1);
+
+	/* Check we are on DFS channel(s) */
+	if (!dfs_check_chans_radar(iface, start_chan_idx, n_chans))
+		return 0;
+
+	/* Reported via radar event */
+	switch (chan_width) {
+	case CHAN_WIDTH_20_NOHT:
+	case CHAN_WIDTH_20:
+		radar_n_chans = 1;
+		if (frequency == 0)
+			frequency = cf1;
+		break;
+	case CHAN_WIDTH_40:
+		radar_n_chans = 2;
+		frequency = cf1 - 10;
+		break;
+	case CHAN_WIDTH_80:
+		radar_n_chans = 4;
+		frequency = cf1 - 30;
+		break;
+	case CHAN_WIDTH_160:
+		radar_n_chans = 8;
+		frequency = cf1 - 70;
+		break;
+	default:
+		wpa_printf(MSG_INFO, "DFS chan_width %d not supported",
+			   chan_width);
+		break;
+	}
+
+	ieee80211_freq_to_chan(frequency, &radar_chan);
+
+	for (i = 0; i < n_chans; i++) {
+		chan = &mode->channels[start_chan_idx + i];
+		if (!(chan->flag & HOSTAPD_CHAN_RADAR))
+			continue;
+		for (j = 0; j < radar_n_chans; j++) {
+			wpa_printf(MSG_DEBUG, "checking our: %d, radar: %d",
+				   chan->chan, radar_chan + j * 4);
+			if (chan->chan == radar_chan + j * 4)
+				res++;
+		}
+	}
+
+	wpa_printf(MSG_DEBUG, "overlapped: %d", res);
+
+	return res;
+}
+
+
+static unsigned int dfs_get_cac_time(struct hostapd_iface *iface,
+				     int start_chan_idx, int n_chans)
+{
+	struct hostapd_channel_data *channel;
+	struct hostapd_hw_modes *mode;
+	int i;
+	unsigned int cac_time_ms = 0;
+#ifdef CONFIG_DFS_CAC_TIMER
+	/* Yewei, add dfs cac timer in seconds,, 20240118 */
+	if (iface->conf->dfs_cac_s) {
+		cac_time_ms = iface->conf->dfs_cac_s * 1000;
+		return cac_time_ms;
+	}
+#endif /* CONFIG_DFS_CAC_TIMER */
+	mode = iface->current_mode;
+
+	for (i = 0; i < n_chans; i++) {
+		if (start_chan_idx + i >= mode->num_channels)
+			break;
+		channel = &mode->channels[start_chan_idx + i];
+		if (!(channel->flag & HOSTAPD_CHAN_RADAR))
+			continue;
+		if (channel->dfs_cac_ms > cac_time_ms)
+			cac_time_ms = channel->dfs_cac_ms;
+	}
+
+	return cac_time_ms;
+}
+
+
+/*
+ * Main DFS handler
+ * 1 - continue channel/ap setup
+ * 0 - channel/ap setup will be continued after CAC
+ * -1 - hit critical error
+ */
+int hostapd_handle_dfs(struct hostapd_iface *iface)
+{
+	int res, n_chans, n_chans1, start_chan_idx, start_chan_idx1;
+	int skip_radar = 0;
+
+	if (is_6ghz_freq(iface->freq))
+		return 1;
+
+	if (!iface->current_mode) {
+		/*
+		 * This can happen with drivers that do not provide mode
+		 * information and as such, cannot really use hostapd for DFS.
+		 */
+		wpa_printf(MSG_DEBUG,
+			   "DFS: No current_mode information - assume no need to perform DFS operations by hostapd");
+		return 1;
+	}
+
+	iface->cac_started = 0;
+
+	do {
+		/* Get start (first) channel for current configuration */
+		start_chan_idx = dfs_get_start_chan_idx(iface,
+							&start_chan_idx1);
+		if (start_chan_idx == -1)
+			return -1;
+
+		/* Get number of used channels, depend on width */
+		n_chans = dfs_get_used_n_chans(iface, &n_chans1);
+
+		/* Setup CAC time */
+		iface->dfs_cac_ms = dfs_get_cac_time(iface, start_chan_idx,
+						     n_chans);
+
+		/* Check if any of configured channels require DFS */
+		res = dfs_check_chans_radar(iface, start_chan_idx, n_chans);
+		wpa_printf(MSG_DEBUG,
+			   "DFS %d channels required radar detection",
+			   res);
+		if (!res)
+			return 1;
+
+		/* Check if all channels are DFS available */
+		res = dfs_check_chans_available(iface, start_chan_idx, n_chans);
+		wpa_printf(MSG_DEBUG,
+			   "DFS all channels available, (SKIP CAC): %s",
+			   res ? "yes" : "no");
+		if (res)
+			return 1;
+
+		/* Check if any of configured channels is unavailable */
+		res = dfs_check_chans_unavailable(iface, start_chan_idx,
+						  n_chans);
+		wpa_printf(MSG_DEBUG, "DFS %d chans unavailable - choose other channel: %s",
+			   res, res ? "yes": "no");
+		if (res) {
+			if (dfs_set_valid_channel(iface, skip_radar) < 0) {
+				hostapd_set_state(iface, HAPD_IFACE_DFS);
+				return 0;
+			}
+		}
+	} while (res);
+
+	/* Finally start CAC */
+	hostapd_set_state(iface, HAPD_IFACE_DFS);
+	wpa_printf(MSG_DEBUG, "DFS start CAC on %d MHz%s", iface->freq,
+		   dfs_use_radar_background(iface) ? " (background)" : "");
+	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_CAC_START
+		"freq=%d chan=%d sec_chan=%d, width=%d, seg0=%d, seg1=%d, cac_time=%ds",
+		iface->freq,
+		iface->conf->channel, iface->conf->secondary_channel,
+		hostapd_get_oper_chwidth(iface->conf),
+		hostapd_get_oper_centr_freq_seg0_idx(iface->conf),
+		hostapd_get_oper_centr_freq_seg1_idx(iface->conf),
+		iface->dfs_cac_ms / 1000);
+
+	res = hostapd_start_dfs_cac(
+		iface, iface->conf->hw_mode, iface->freq, iface->conf->channel,
+		iface->conf->ieee80211n, iface->conf->ieee80211ac,
+		iface->conf->ieee80211ax, iface->conf->ieee80211be,
+		iface->conf->secondary_channel,
+		hostapd_get_oper_chwidth(iface->conf),
+		hostapd_get_oper_centr_freq_seg0_idx(iface->conf),
+		hostapd_get_oper_centr_freq_seg1_idx(iface->conf),
+		dfs_use_radar_background(iface));
+
+	if (res) {
+		wpa_printf(MSG_ERROR, "DFS start_dfs_cac() failed, %d", res);
+		return -1;
+	}
+
+	if (dfs_use_radar_background(iface)) {
+		/* Cache background radar parameters. */
+		iface->radar_background.channel = iface->conf->channel;
+		iface->radar_background.secondary_channel =
+			iface->conf->secondary_channel;
+		iface->radar_background.freq = iface->freq;
+		iface->radar_background.centr_freq_seg0_idx =
+			hostapd_get_oper_centr_freq_seg0_idx(iface->conf);
+		iface->radar_background.centr_freq_seg1_idx =
+			hostapd_get_oper_centr_freq_seg1_idx(iface->conf);
+
+		/*
+		 * Let's select a random channel according to the
+		 * regulations and perform CAC on dedicated radar chain.
+		 */
+		res = dfs_set_valid_channel(iface, 1);
+		if (res < 0)
+			return res;
+
+		iface->radar_background.temp_ch = 1;
+		return 1;
+	}
+
+	return 0;
+}
+
+
+int hostapd_is_dfs_chan_available(struct hostapd_iface *iface)
+{
+	int n_chans, n_chans1, start_chan_idx, start_chan_idx1;
+
+	/* Get the start (first) channel for current configuration */
+	start_chan_idx = dfs_get_start_chan_idx(iface, &start_chan_idx1);
+	if (start_chan_idx < 0)
+		return 0;
+
+	/* Get the number of used channels, depending on width */
+	n_chans = dfs_get_used_n_chans(iface, &n_chans1);
+
+	/* Check if all channels are DFS available */
+	return dfs_check_chans_available(iface, start_chan_idx, n_chans);
+}
+
+
+static int hostapd_dfs_request_channel_switch(struct hostapd_iface *iface,
+					      int channel, int freq,
+					      int secondary_channel,
+					      u8 current_vht_oper_chwidth,
+					      u8 oper_centr_freq_seg0_idx,
+					      u8 oper_centr_freq_seg1_idx)
+{
+	struct hostapd_hw_modes *cmode = iface->current_mode;
+	int ieee80211_mode = IEEE80211_MODE_AP, err;
+	struct csa_settings csa_settings;
+	u8 new_vht_oper_chwidth;
+	unsigned int i;
+
+	wpa_printf(MSG_DEBUG, "DFS will switch to a new channel %d", channel);
+	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_NEW_CHANNEL
+		"freq=%d chan=%d sec_chan=%d", freq, channel,
+		secondary_channel);
+
+	new_vht_oper_chwidth = hostapd_get_oper_chwidth(iface->conf);
+	hostapd_set_oper_chwidth(iface->conf, current_vht_oper_chwidth);
+
+	/* Setup CSA request */
+	os_memset(&csa_settings, 0, sizeof(csa_settings));
+	csa_settings.cs_count = 5;
+	csa_settings.block_tx = 1;
+#ifdef CONFIG_MESH
+	if (iface->mconf)
+		ieee80211_mode = IEEE80211_MODE_MESH;
+#endif /* CONFIG_MESH */
+	err = hostapd_set_freq_params(&csa_settings.freq_params,
+				      iface->conf->hw_mode,
+				      freq, channel,
+				      iface->conf->enable_edmg,
+				      iface->conf->edmg_channel,
+				      iface->conf->ieee80211n,
+				      iface->conf->ieee80211ac,
+				      iface->conf->ieee80211ax,
+				      iface->conf->ieee80211be,
+				      secondary_channel,
+				      new_vht_oper_chwidth,
+				      oper_centr_freq_seg0_idx,
+				      oper_centr_freq_seg1_idx,
+				      cmode->vht_capab,
+				      &cmode->he_capab[ieee80211_mode],
+				      &cmode->eht_capab[ieee80211_mode]);
+
+	if (err) {
+		wpa_printf(MSG_ERROR,
+			   "DFS failed to calculate CSA freq params");
+		hostapd_disable_iface(iface);
+		return err;
+	}
+
+	for (i = 0; i < iface->num_bss; i++) {
+		err = hostapd_switch_channel(iface->bss[i], &csa_settings);
+		if (err)
+			break;
+	}
+
+	if (err) {
+		wpa_printf(MSG_WARNING,
+			   "DFS failed to schedule CSA (%d) - trying fallback",
+			   err);
+		iface->freq = freq;
+		iface->conf->channel = channel;
+		iface->conf->secondary_channel = secondary_channel;
+		hostapd_set_oper_chwidth(iface->conf, new_vht_oper_chwidth);
+		hostapd_set_oper_centr_freq_seg0_idx(iface->conf,
+						     oper_centr_freq_seg0_idx);
+		hostapd_set_oper_centr_freq_seg1_idx(iface->conf,
+						     oper_centr_freq_seg1_idx);
+
+		hostapd_disable_iface(iface);
+		hostapd_enable_iface(iface);
+
+		return 0;
+	}
+
+	/* Channel configuration will be updated once CSA completes and
+	 * ch_switch_notify event is received */
+	wpa_printf(MSG_DEBUG, "DFS waiting channel switch event");
+
+	return 0;
+}
+
+
+static void hostpad_dfs_update_background_chain(struct hostapd_iface *iface)
+{
+	int sec = 0;
+	enum dfs_channel_type channel_type = DFS_NO_CAC_YET;
+	struct hostapd_channel_data *channel;
+	u8 oper_centr_freq_seg0_idx = 0;
+	u8 oper_centr_freq_seg1_idx = 0;
+
+	/*
+	 * Allow selection of DFS channel in ETSI to comply with
+	 * uniform spreading.
+	 */
+	if (iface->dfs_domain == HOSTAPD_DFS_REGION_ETSI)
+		channel_type = DFS_ANY_CHANNEL;
+
+	channel = dfs_get_valid_channel(iface, &sec, &oper_centr_freq_seg0_idx,
+					&oper_centr_freq_seg1_idx,
+					channel_type);
+	if (!channel ||
+	    channel->chan == iface->conf->channel ||
+	    channel->chan == iface->radar_background.channel)
+		channel = dfs_downgrade_bandwidth(iface, &sec,
+						  &oper_centr_freq_seg0_idx,
+						  &oper_centr_freq_seg1_idx,
+						  &channel_type);
+	if (!channel ||
+	    hostapd_start_dfs_cac(iface, iface->conf->hw_mode,
+				  channel->freq, channel->chan,
+				  iface->conf->ieee80211n,
+				  iface->conf->ieee80211ac,
+				  iface->conf->ieee80211ax,
+				  iface->conf->ieee80211be,
+				  sec, hostapd_get_oper_chwidth(iface->conf),
+				  oper_centr_freq_seg0_idx,
+				  oper_centr_freq_seg1_idx, true)) {
+		wpa_printf(MSG_ERROR, "DFS failed to start CAC offchannel");
+		iface->radar_background.channel = -1;
+		return;
+	}
+
+	iface->radar_background.channel = channel->chan;
+	iface->radar_background.freq = channel->freq;
+	iface->radar_background.secondary_channel = sec;
+	iface->radar_background.centr_freq_seg0_idx = oper_centr_freq_seg0_idx;
+	iface->radar_background.centr_freq_seg1_idx = oper_centr_freq_seg1_idx;
+
+	wpa_printf(MSG_DEBUG,
+		   "%s: setting background chain to chan %d (%d MHz)",
+		   __func__, channel->chan, channel->freq);
+}
+
+
+static bool
+hostapd_dfs_is_background_event(struct hostapd_iface *iface, int freq)
+{
+	return dfs_use_radar_background(iface) &&
+		iface->radar_background.channel != -1 &&
+		iface->radar_background.freq == freq;
+}
+
+
+static int
+hostapd_dfs_start_channel_switch_background(struct hostapd_iface *iface)
+{
+	u8 current_vht_oper_chwidth = hostapd_get_oper_chwidth(iface->conf);
+
+	iface->conf->channel = iface->radar_background.channel;
+	iface->freq = iface->radar_background.freq;
+	iface->conf->secondary_channel =
+		iface->radar_background.secondary_channel;
+	hostapd_set_oper_centr_freq_seg0_idx(
+		iface->conf, iface->radar_background.centr_freq_seg0_idx);
+	hostapd_set_oper_centr_freq_seg1_idx(
+		iface->conf, iface->radar_background.centr_freq_seg1_idx);
+
+	hostpad_dfs_update_background_chain(iface);
+
+	return hostapd_dfs_request_channel_switch(
+		iface, iface->conf->channel, iface->freq,
+		iface->conf->secondary_channel, current_vht_oper_chwidth,
+		hostapd_get_oper_centr_freq_seg0_idx(iface->conf),
+		hostapd_get_oper_centr_freq_seg1_idx(iface->conf));
+}
+
+
+int hostapd_dfs_complete_cac(struct hostapd_iface *iface, int success, int freq,
+			     int ht_enabled, int chan_offset, int chan_width,
+			     int cf1, int cf2)
+{
+	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_CAC_COMPLETED
+		"success=%d freq=%d ht_enabled=%d chan_offset=%d chan_width=%d cf1=%d cf2=%d",
+		success, freq, ht_enabled, chan_offset, chan_width, cf1, cf2);
+
+	if (success) {
+		/* Complete iface/ap configuration */
+		if (iface->drv_flags & WPA_DRIVER_FLAGS_DFS_OFFLOAD) {
+			/* Complete AP configuration for the first bring up. */
+			if (iface->state != HAPD_IFACE_ENABLED)
+				hostapd_setup_interface_complete(iface, 0);
+			else
+				iface->cac_started = 0;
+		} else {
+			set_dfs_state(iface, freq, ht_enabled, chan_offset,
+				      chan_width, cf1, cf2,
+				      HOSTAPD_CHAN_DFS_AVAILABLE);
+
+			/*
+			 * Radar event from background chain for the selected
+			 * channel. Perform CSA, move the main chain to the
+			 * selected channel and configure the background chain
+			 * to a new DFS channel.
+			 */
+			if (hostapd_dfs_is_background_event(iface, freq)) {
+				iface->radar_background.cac_started = 0;
+				if (!iface->radar_background.temp_ch)
+					return 0;
+
+				iface->radar_background.temp_ch = 0;
+				return hostapd_dfs_start_channel_switch_background(iface);
+			}
+
+			/*
+			 * Just mark the channel available when CAC completion
+			 * event is received in enabled state. CAC result could
+			 * have been propagated from another radio having the
+			 * same regulatory configuration. When CAC completion is
+			 * received during non-HAPD_IFACE_ENABLED state, make
+			 * sure the configured channel is available because this
+			 * CAC completion event could have been propagated from
+			 * another radio.
+			 */
+			if (iface->state != HAPD_IFACE_ENABLED &&
+			    hostapd_is_dfs_chan_available(iface)) {
+				hostapd_setup_interface_complete(iface, 0);
+				iface->cac_started = 0;
+			}
+		}
+	} else if (hostapd_dfs_is_background_event(iface, freq)) {
+		iface->radar_background.cac_started = 0;
+		hostpad_dfs_update_background_chain(iface);
+	}
+
+	return 0;
+}
+
+
+int hostapd_dfs_pre_cac_expired(struct hostapd_iface *iface, int freq,
+				int ht_enabled, int chan_offset, int chan_width,
+				int cf1, int cf2)
+{
+	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_PRE_CAC_EXPIRED
+		"freq=%d ht_enabled=%d chan_offset=%d chan_width=%d cf1=%d cf2=%d",
+		freq, ht_enabled, chan_offset, chan_width, cf1, cf2);
+
+	hostapd_ubus_notify_radar_detected(iface, freq, chan_width, cf1, cf2);
+
+	/* Proceed only if DFS is not offloaded to the driver */
+	if (iface->drv_flags & WPA_DRIVER_FLAGS_DFS_OFFLOAD)
+		return 0;
+
+	set_dfs_state(iface, freq, ht_enabled, chan_offset, chan_width,
+		      cf1, cf2, HOSTAPD_CHAN_DFS_USABLE);
+
+	return 0;
+}
+
+
+static struct hostapd_channel_data *
+dfs_downgrade_bandwidth(struct hostapd_iface *iface, int *secondary_channel,
+			u8 *oper_centr_freq_seg0_idx,
+			u8 *oper_centr_freq_seg1_idx,
+			enum dfs_channel_type *channel_type)
+{
+	struct hostapd_channel_data *channel;
+
+	for (;;) {
+		channel = dfs_get_valid_channel(iface, secondary_channel,
+						oper_centr_freq_seg0_idx,
+						oper_centr_freq_seg1_idx,
+						*channel_type);
+		if (channel) {
+			wpa_printf(MSG_DEBUG, "DFS: Selected channel: %d",
+				   channel->chan);
+			return channel;
+		}
+
+		if (*channel_type != DFS_ANY_CHANNEL) {
+			*channel_type = DFS_ANY_CHANNEL;
+		} else {
+			int oper_chwidth;
+
+			oper_chwidth = hostapd_get_oper_chwidth(iface->conf);
+			if (oper_chwidth == CONF_OPER_CHWIDTH_USE_HT)
+				break;
+			*channel_type = DFS_AVAILABLE;
+			hostapd_set_oper_chwidth(iface->conf, oper_chwidth - 1);
+		}
+	}
+
+	wpa_printf(MSG_INFO,
+		   "%s: no DFS channels left, waiting for NOP to finish",
+		   __func__);
+	return NULL;
+}
+
+
+static int hostapd_dfs_start_channel_switch_cac(struct hostapd_iface *iface)
+{
+	struct hostapd_channel_data *channel;
+	int secondary_channel;
+	u8 oper_centr_freq_seg0_idx = 0;
+	u8 oper_centr_freq_seg1_idx = 0;
+	enum dfs_channel_type channel_type = DFS_ANY_CHANNEL;
+	int err = 1;
+
+	/* Radar detected during active CAC */
+	iface->cac_started = 0;
+	channel = dfs_get_valid_channel(iface, &secondary_channel,
+					&oper_centr_freq_seg0_idx,
+					&oper_centr_freq_seg1_idx,
+					channel_type);
+
+	if (!channel) {
+		channel = dfs_downgrade_bandwidth(iface, &secondary_channel,
+						  &oper_centr_freq_seg0_idx,
+						  &oper_centr_freq_seg1_idx,
+						  &channel_type);
+		if (!channel) {
+			wpa_printf(MSG_ERROR, "No valid channel available");
+			return err;
+		}
+	}
+
+	wpa_printf(MSG_DEBUG, "DFS will switch to a new channel %d",
+		   channel->chan);
+	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_NEW_CHANNEL
+		"freq=%d chan=%d sec_chan=%d", channel->freq,
+		channel->chan, secondary_channel);
+
+	iface->freq = channel->freq;
+	iface->conf->channel = channel->chan;
+	iface->conf->secondary_channel = secondary_channel;
+	hostapd_set_oper_centr_freq_seg0_idx(iface->conf,
+					     oper_centr_freq_seg0_idx);
+	hostapd_set_oper_centr_freq_seg1_idx(iface->conf,
+					     oper_centr_freq_seg1_idx);
+	err = 0;
+
+	hostapd_setup_interface_complete(iface, err);
+	return err;
+}
+
+
+static int
+hostapd_dfs_background_start_channel_switch(struct hostapd_iface *iface,
+					    int freq)
+{
+	if (!dfs_use_radar_background(iface))
+		return -1; /* Background radar chain not supported. */
+
+	wpa_printf(MSG_DEBUG,
+		   "%s called (background CAC active: %s, CSA active: %s)",
+		   __func__, iface->radar_background.cac_started ? "yes" : "no",
+		   hostapd_csa_in_progress(iface) ? "yes" : "no");
+
+	/* Check if CSA in progress */
+	if (hostapd_csa_in_progress(iface))
+		return 0;
+
+	if (hostapd_dfs_is_background_event(iface, freq)) {
+		/*
+		 * Radar pattern is reported on the background chain.
+		 * Just select a new random channel according to the
+		 * regulations for monitoring.
+		 */
+		hostpad_dfs_update_background_chain(iface);
+		return 0;
+	}
+
+	/*
+	 * If background radar detection is supported and the radar channel
+	 * monitored by the background chain is available switch to it without
+	 * waiting for the CAC.
+	 */
+	if (iface->radar_background.channel == -1)
+		return -1; /* Background radar chain not available. */
+
+	if (iface->radar_background.cac_started) {
+		/*
+		 * Background channel not available yet. Perform CAC on the
+		 * main chain.
+		 */
+		iface->radar_background.temp_ch = 1;
+		return -1;
+	}
+
+	return hostapd_dfs_start_channel_switch_background(iface);
+}
+
+
+static int hostapd_dfs_start_channel_switch(struct hostapd_iface *iface)
+{
+	struct hostapd_channel_data *channel;
+	int secondary_channel;
+	u8 oper_centr_freq_seg0_idx;
+	u8 oper_centr_freq_seg1_idx;
+	enum dfs_channel_type channel_type = DFS_AVAILABLE;
+	u8 current_vht_oper_chwidth = hostapd_get_oper_chwidth(iface->conf);
+
+	wpa_printf(MSG_DEBUG, "%s called (CAC active: %s, CSA active: %s)",
+		   __func__, iface->cac_started ? "yes" : "no",
+		   hostapd_csa_in_progress(iface) ? "yes" : "no");
+
+	/* Check if CSA in progress */
+	if (hostapd_csa_in_progress(iface))
+		return 0;
+
+	/* Check if active CAC */
+	if (iface->cac_started)
+		return hostapd_dfs_start_channel_switch_cac(iface);
+
+	/*
+	 * Allow selection of DFS channel in ETSI to comply with
+	 * uniform spreading.
+	 */
+	if (iface->dfs_domain == HOSTAPD_DFS_REGION_ETSI)
+		channel_type = DFS_ANY_CHANNEL;
+
+	/* Perform channel switch/CSA */
+	channel = dfs_get_valid_channel(iface, &secondary_channel,
+					&oper_centr_freq_seg0_idx,
+					&oper_centr_freq_seg1_idx,
+					channel_type);
+
+	if (!channel) {
+		/*
+		 * If there is no channel to switch immediately to, check if
+		 * there is another channel where we can switch even if it
+		 * requires to perform a CAC first.
+		 */
+		channel_type = DFS_ANY_CHANNEL;
+		channel = dfs_downgrade_bandwidth(iface, &secondary_channel,
+						  &oper_centr_freq_seg0_idx,
+						  &oper_centr_freq_seg1_idx,
+						  &channel_type);
+		if (!channel) {
+			/*
+			 * Toggle interface state to enter DFS state
+			 * until NOP is finished.
+			 */
+			hostapd_disable_iface(iface);
+			hostapd_enable_iface(iface);
+			return 0;
+		}
+
+		if (channel_type == DFS_ANY_CHANNEL) {
+			iface->freq = channel->freq;
+			iface->conf->channel = channel->chan;
+			iface->conf->secondary_channel = secondary_channel;
+			hostapd_set_oper_centr_freq_seg0_idx(
+				iface->conf, oper_centr_freq_seg0_idx);
+			hostapd_set_oper_centr_freq_seg1_idx(
+				iface->conf, oper_centr_freq_seg1_idx);
+
+			hostapd_disable_iface(iface);
+			hostapd_enable_iface(iface);
+			return 0;
+		}
+	}
+
+	return hostapd_dfs_request_channel_switch(iface, channel->chan,
+						  channel->freq,
+						  secondary_channel,
+						  current_vht_oper_chwidth,
+						  oper_centr_freq_seg0_idx,
+						  oper_centr_freq_seg1_idx);
+}
+
+
+int hostapd_dfs_radar_detected(struct hostapd_iface *iface, int freq,
+			       int ht_enabled, int chan_offset, int chan_width,
+			       int cf1, int cf2)
+{
+	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_RADAR_DETECTED
+		"freq=%d ht_enabled=%d chan_offset=%d chan_width=%d cf1=%d cf2=%d",
+		freq, ht_enabled, chan_offset, chan_width, cf1, cf2);
+
+	/* Proceed only if DFS is not offloaded to the driver */
+	if (iface->drv_flags & WPA_DRIVER_FLAGS_DFS_OFFLOAD)
+		return 0;
+
+	if (!iface->conf->ieee80211h)
+		return 0;
+
+	/* mark radar frequency as invalid */
+	if (!set_dfs_state(iface, freq, ht_enabled, chan_offset, chan_width,
+			   cf1, cf2, HOSTAPD_CHAN_DFS_UNAVAILABLE))
+		return 0;
+
+	if (!hostapd_dfs_is_background_event(iface, freq)) {
+		/* Skip if reported radar event not overlapped our channels */
+		if (!dfs_are_channels_overlapped(iface, freq, chan_width,
+						 cf1, cf2))
+			return 0;
+	}
+
+	if (hostapd_dfs_background_start_channel_switch(iface, freq)) {
+		/* Radar detected while operating, switch the channel. */
+		return hostapd_dfs_start_channel_switch(iface);
+	}
+
+	return 0;
+}
+
+
+int hostapd_dfs_nop_finished(struct hostapd_iface *iface, int freq,
+			     int ht_enabled, int chan_offset, int chan_width,
+			     int cf1, int cf2)
+{
+	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_NOP_FINISHED
+		"freq=%d ht_enabled=%d chan_offset=%d chan_width=%d cf1=%d cf2=%d",
+		freq, ht_enabled, chan_offset, chan_width, cf1, cf2);
+
+	/* Proceed only if DFS is not offloaded to the driver */
+	if (iface->drv_flags & WPA_DRIVER_FLAGS_DFS_OFFLOAD)
+		return 0;
+
+	/* TODO add correct implementation here */
+	set_dfs_state(iface, freq, ht_enabled, chan_offset, chan_width,
+		      cf1, cf2, HOSTAPD_CHAN_DFS_USABLE);
+
+	if (iface->state == HAPD_IFACE_DFS && !iface->cac_started) {
+		/* Handle cases where all channels were initially unavailable */
+		hostapd_handle_dfs(iface);
+	} else if (dfs_use_radar_background(iface) &&
+		   iface->radar_background.channel == -1) {
+		/* Reset radar background chain if disabled */
+		hostpad_dfs_update_background_chain(iface);
+	}
+
+	return 0;
+}
+
+
+int hostapd_is_dfs_required(struct hostapd_iface *iface)
+{
+	int n_chans, n_chans1, start_chan_idx, start_chan_idx1, res;
+
+	if ((!(iface->drv_flags & WPA_DRIVER_FLAGS_DFS_OFFLOAD) &&
+	     !iface->conf->ieee80211h) ||
+	    !iface->current_mode ||
+	    iface->current_mode->mode != HOSTAPD_MODE_IEEE80211A)
+		return 0;
+
+	/* Get start (first) channel for current configuration */
+	start_chan_idx = dfs_get_start_chan_idx(iface, &start_chan_idx1);
+	if (start_chan_idx == -1)
+		return -1;
+
+	/* Get number of used channels, depend on width */
+	n_chans = dfs_get_used_n_chans(iface, &n_chans1);
+
+	/* Check if any of configured channels require DFS */
+	res = dfs_check_chans_radar(iface, start_chan_idx, n_chans);
+	if (res)
+		return res;
+	if (start_chan_idx1 >= 0 && n_chans1 > 0)
+		res = dfs_check_chans_radar(iface, start_chan_idx1, n_chans1);
+	return res;
+}
+
+
+int hostapd_dfs_start_cac(struct hostapd_iface *iface, int freq,
+			  int ht_enabled, int chan_offset, int chan_width,
+			  int cf1, int cf2)
+{
+	if (hostapd_dfs_is_background_event(iface, freq)) {
+		iface->radar_background.cac_started = 1;
+	} else {
+		/* This is called when the driver indicates that an offloaded
+		 * DFS has started CAC. */
+		hostapd_set_state(iface, HAPD_IFACE_DFS);
+		iface->cac_started = 1;
+	}
+	/* TODO: How to check CAC time for ETSI weather channels? */
+#ifdef CONFIG_DFS_CAC_TIMER
+	/* Yewei, add dfs cac timer in seconds, 20240118 */
+	if (iface->conf->dfs_cac_s) {
+		iface->dfs_cac_ms = iface->conf->dfs_cac_s * 1000;
+	}
+	else
+#endif /* CONFIG_DFS_CAC_TIMER */
+	{
+		iface->dfs_cac_ms = 60000;
+	}
+	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_CAC_START
+		"freq=%d chan=%d chan_offset=%d width=%d seg0=%d "
+		"seg1=%d cac_time=%ds%s",
+		freq, (freq - 5000) / 5, chan_offset, chan_width, cf1, cf2,
+		iface->dfs_cac_ms / 1000,
+		hostapd_dfs_is_background_event(iface, freq) ?
+		" (background)" : "");
+
+	os_get_reltime(&iface->dfs_cac_start);
+	return 0;
+}
+
+
+/*
+ * Main DFS handler for offloaded case.
+ * 2 - continue channel/AP setup for non-DFS channel
+ * 1 - continue channel/AP setup for DFS channel
+ * 0 - channel/AP setup will be continued after CAC
+ * -1 - hit critical error
+ */
+int hostapd_handle_dfs_offload(struct hostapd_iface *iface)
+{
+	int dfs_res;
+
+	wpa_printf(MSG_DEBUG, "%s: iface->cac_started: %d",
+		   __func__, iface->cac_started);
+
+	/*
+	 * If DFS has already been started, then we are being called from a
+	 * callback to continue AP/channel setup. Reset the CAC start flag and
+	 * return.
+	 */
+	if (iface->cac_started) {
+		wpa_printf(MSG_DEBUG, "%s: iface->cac_started: %d",
+			   __func__, iface->cac_started);
+		iface->cac_started = 0;
+		return 1;
+	}
+
+	dfs_res = hostapd_is_dfs_required(iface);
+	if (dfs_res > 0) {
+		wpa_printf(MSG_DEBUG,
+			   "%s: freq %d MHz requires DFS for %d chans",
+			   __func__, iface->freq, dfs_res);
+		return 0;
+	}
+
+	wpa_printf(MSG_DEBUG,
+		   "%s: freq %d MHz does not require DFS. Continue channel/AP setup",
+		   __func__, iface->freq);
+	return 2;
+}
+
+
+int hostapd_is_dfs_overlap(struct hostapd_iface *iface, enum chan_width width,
+			   int center_freq)
+{
+	struct hostapd_channel_data *chan;
+	struct hostapd_hw_modes *mode = iface->current_mode;
+	int half_width;
+	int res = 0;
+	int i;
+
+	if (!iface->conf->ieee80211h || !mode ||
+	    mode->mode != HOSTAPD_MODE_IEEE80211A)
+		return 0;
+
+	switch (width) {
+	case CHAN_WIDTH_20_NOHT:
+	case CHAN_WIDTH_20:
+		half_width = 10;
+		break;
+	case CHAN_WIDTH_40:
+		half_width = 20;
+		break;
+	case CHAN_WIDTH_80:
+	case CHAN_WIDTH_80P80:
+		half_width = 40;
+		break;
+	case CHAN_WIDTH_160:
+		half_width = 80;
+		break;
+	default:
+		wpa_printf(MSG_WARNING, "DFS chanwidth %d not supported",
+			   width);
+		return 0;
+	}
+
+	for (i = 0; i < mode->num_channels; i++) {
+		chan = &mode->channels[i];
+
+		if (!(chan->flag & HOSTAPD_CHAN_RADAR))
+			continue;
+
+		if ((chan->flag & HOSTAPD_CHAN_DFS_MASK) ==
+		    HOSTAPD_CHAN_DFS_AVAILABLE)
+			continue;
+
+		if (center_freq - chan->freq < half_width &&
+		    chan->freq - center_freq < half_width)
+			res++;
+	}
+
+	wpa_printf(MSG_DEBUG, "DFS CAC required: (%d, %d): in range: %s",
+		   center_freq - half_width, center_freq + half_width,
+		   res ? "yes" : "no");
+
+	return res;
+}