AP: Handle 6 GHz AP state machine with NO_IR flags

AP cannot come up in channels that are marked as NO_IR. If AP moves to
HAPD_IFACE_DISABLED state, it will deinitialize the nl80211 driver
interface and sockets.

Hence, introduce a new state called HAPD_IFACE_NO_IR, for 6 GHz APs to
handle NO_IR scenarios, such as AFC, where the channels not allowed by
AFC will have HOSTAPD_CHAN_NO_IR flag set. In this state, AP is still
kept in a non-operational state (stopped) without deinitializing the
nl80211 driver interface. wiphy reg change event can then update the
channels and bring up the AP in a valid channel.

Signed-off-by: Pooventhiran G <quic_pooventh@quicinc.com>

src/ap/acs.c

@@ -1353,12 +1353,20 @@ static int acs_request_scan(struct hostapd_iface *iface)
 
 enum hostapd_chan_status acs_init(struct hostapd_iface *iface)
 {
+	int err;
+
 	wpa_printf(MSG_INFO, "ACS: Automatic channel selection started, this may take a bit");
 
 	if (iface->drv_flags & WPA_DRIVER_FLAGS_ACS_OFFLOAD) {
 		wpa_printf(MSG_INFO, "ACS: Offloading to driver");
-		if (hostapd_drv_do_acs(iface->bss[0]))
+
+		err = hostapd_drv_do_acs(iface->bss[0]);
+		if (err) {
+			if (err == 1)
+				return HOSTAPD_CHAN_INVALID_NO_IR;
 			return HOSTAPD_CHAN_INVALID;
+		}
+
 		return HOSTAPD_CHAN_ACS;
 	}
 

src/ap/ap_drv_ops.c

@@ -646,8 +646,8 @@ struct hostapd_hw_modes *
 hostapd_get_hw_feature_data(struct hostapd_data *hapd, u16 *num_modes,
 			    u16 *flags, u8 *dfs_domain)
 {
-	if (hapd->driver == NULL ||
+	if (!hapd->driver || !hapd->driver->get_hw_feature_data ||
-	    hapd->driver->get_hw_feature_data == NULL)
+	    !hapd->drv_priv)
 		return NULL;
 	return hapd->driver->get_hw_feature_data(hapd->drv_priv, num_modes,
 						 flags, dfs_domain);
@@ -889,6 +889,7 @@ void hostapd_get_hw_mode_any_channels(struct hostapd_data *hapd,
 				      int **freq_list)
 {
 	int i;
+	bool is_no_ir = false;
 
 	for (i = 0; i < mode->num_channels; i++) {
 		struct hostapd_channel_data *chan = &mode->channels[i];
@@ -917,7 +918,12 @@ void hostapd_get_hw_mode_any_channels(struct hostapd_data *hapd,
 		      (chan->flag & HOSTAPD_CHAN_RADAR)) &&
 		    !(chan->max_tx_power < hapd->iface->conf->min_tx_power))
 			int_array_add_unique(freq_list, chan->freq);
+		else if ((chan->flag & HOSTAPD_CHAN_NO_IR) &&
+			 is_6ghz_freq(chan->freq))
+			is_no_ir = true;
 	}
+
+	hapd->iface->is_no_ir = is_no_ir;
 }
 
 
@@ -935,6 +941,11 @@ void hostapd_get_ext_capa(struct hostapd_iface *iface)
 }
 
 
+/**
+ * hostapd_drv_do_acs - Start automatic channel selection
+ * @hapd: BSS data for the device initiating ACS
+ * Returns: 0 on success, -1 on failure, 1 on failure due to NO_IR (AFC)
+ */
 int hostapd_drv_do_acs(struct hostapd_data *hapd)
 {
 	struct drv_acs_params params;
@@ -972,6 +983,12 @@ int hostapd_drv_do_acs(struct hostapd_data *hapd)
 						 false, &freq_list);
 	}
 
+	if (!freq_list && hapd->iface->is_no_ir) {
+		wpa_printf(MSG_ERROR,
+			   "NO_IR: Interface freq_list is empty. Failing do_acs.");
+		return 1;
+	}
+
 	params.freq_list = freq_list;
 	params.edmg_enabled = hapd->iface->conf->enable_edmg;
 

src/ap/hostapd.c

@@ -1607,6 +1607,125 @@ static int start_ctrl_iface(struct hostapd_iface *iface)
 }
 
 
+/* When NO_IR flag is set and AP is stopped, clean up BSS parameters without
+ * deinitializing the driver and the control interfaces. A subsequent
+ * REG_CHANGE event can bring the AP back up.
+ */
+static void hostapd_no_ir_cleanup(struct hostapd_data *bss)
+{
+	hostapd_bss_deinit_no_free(bss);
+	hostapd_free_hapd_data(bss);
+	hostapd_cleanup_iface_partial(bss->iface);
+}
+
+
+static int hostapd_no_ir_channel_list_updated(struct hostapd_iface *iface,
+					      void *ctx)
+{
+	bool all_no_ir, is_6ghz;
+	int i, j;
+	struct hostapd_hw_modes *mode = NULL;
+
+	if (hostapd_get_hw_features(iface))
+		return 0;
+
+	all_no_ir = true;
+	is_6ghz = false;
+
+	for (i = 0; i < iface->num_hw_features; i++) {
+		mode = &iface->hw_features[i];
+
+		if (mode->mode == iface->conf->hw_mode) {
+			if (iface->freq > 0 &&
+			    !hw_mode_get_channel(mode, iface->freq, NULL)) {
+				mode = NULL;
+				continue;
+			}
+
+			for (j = 0; j < mode->num_channels; j++) {
+				if (!(mode->channels[j].flag &
+				      HOSTAPD_CHAN_NO_IR))
+					all_no_ir = false;
+
+				if (is_6ghz_freq(mode->channels[j].freq))
+					is_6ghz = true;
+			}
+			break;
+		}
+	}
+
+	if (!mode || !is_6ghz)
+		return 0;
+	iface->current_mode = mode;
+
+	if (iface->state == HAPD_IFACE_ENABLED) {
+		if (!all_no_ir) {
+			struct hostapd_channel_data *chan;
+
+			chan = hw_get_channel_freq(iface->current_mode->mode,
+						   iface->freq, NULL,
+						   iface->hw_features,
+						   iface->num_hw_features);
+
+			if (!chan) {
+				wpa_printf(MSG_ERROR,
+					   "NO_IR: Could not derive chan from freq");
+				return 0;
+			}
+
+			if (!(chan->flag & HOSTAPD_CHAN_NO_IR))
+				return 0;
+			wpa_printf(MSG_DEBUG,
+				   "NO_IR: The current channel has NO_IR flag now, stop AP.");
+		} else {
+			wpa_printf(MSG_DEBUG,
+				   "NO_IR: All chan in new chanlist are NO_IR, stop AP.");
+		}
+
+		hostapd_set_state(iface, HAPD_IFACE_NO_IR);
+		iface->is_no_ir = true;
+		hostapd_drv_stop_ap(iface->bss[0]);
+		hostapd_no_ir_cleanup(iface->bss[0]);
+		wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, AP_EVENT_NO_IR);
+	} else if (iface->state == HAPD_IFACE_NO_IR) {
+		if (all_no_ir) {
+			wpa_printf(MSG_DEBUG,
+				   "NO_IR: AP in NO_IR and all chan in the new chanlist are NO_IR. Ignore");
+			return 0;
+		}
+
+		if (!iface->conf->acs) {
+			struct hostapd_channel_data *chan;
+
+			chan = hw_get_channel_freq(iface->current_mode->mode,
+						   iface->freq, NULL,
+						   iface->hw_features,
+						   iface->num_hw_features);
+			if (!chan) {
+				wpa_printf(MSG_ERROR,
+					   "NO_IR: Could not derive chan from freq");
+				return 0;
+			}
+
+			/* If the last operating channel is NO_IR, trigger ACS.
+			 */
+			if (chan->flag & HOSTAPD_CHAN_NO_IR) {
+				iface->freq = 0;
+				iface->conf->channel = 0;
+				if (acs_init(iface) != HOSTAPD_CHAN_ACS)
+					wpa_printf(MSG_ERROR,
+						   "NO_IR: Could not start ACS");
+				return 0;
+			}
+		}
+
+		setup_interface2(iface);
+	}
+
+	return 0;
+}
+
+
 static void channel_list_update_timeout(void *eloop_ctx, void *timeout_ctx)
 {
 	struct hostapd_iface *iface = eloop_ctx;
@@ -1627,6 +1746,13 @@ static void channel_list_update_timeout(void *eloop_ctx, void *timeout_ctx)
 
 void hostapd_channel_list_updated(struct hostapd_iface *iface, int initiator)
 {
+	if (initiator == REGDOM_SET_BY_DRIVER) {
+		hostapd_for_each_interface(iface->interfaces,
+					   hostapd_no_ir_channel_list_updated,
+					   NULL);
+		return;
+	}
+
 	if (!iface->wait_channel_update || initiator != REGDOM_SET_BY_USER)
 		return;
 
@@ -1776,6 +1902,7 @@ static void hostapd_set_6ghz_sec_chan(struct hostapd_iface *iface)
 static int setup_interface2(struct hostapd_iface *iface)
 {
 	iface->wait_channel_update = 0;
+	iface->is_no_ir = false;
 
 	if (hostapd_get_hw_features(iface)) {
 		/* Not all drivers support this yet, so continue without hw
@@ -1831,6 +1958,14 @@ static int setup_interface2(struct hostapd_iface *iface)
 	return hostapd_setup_interface_complete(iface, 0);
 
 fail:
+	if (iface->is_no_ir) {
+		/* If AP is in NO_IR state, it can be reenabled by the driver
+		 * regulatory update and EVENT_CHANNEL_LIST_CHANGED. */
+		hostapd_set_state(iface, HAPD_IFACE_NO_IR);
+		wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, AP_EVENT_NO_IR);
+		return 0;
+	}
+
 	hostapd_set_state(iface, HAPD_IFACE_DISABLED);
 	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, AP_EVENT_DISABLED);
 	if (iface->interfaces && iface->interfaces->terminate_on_error)
@@ -2321,6 +2456,13 @@ dfs_offload:
 
 fail:
 	wpa_printf(MSG_ERROR, "Interface initialization failed");
+
+	if (iface->is_no_ir) {
+		hostapd_set_state(iface, HAPD_IFACE_NO_IR);
+		wpa_msg(hapd->msg_ctx, MSG_INFO, AP_EVENT_NO_IR);
+		return 0;
+	}
+
 	hostapd_set_state(iface, HAPD_IFACE_DISABLED);
 	wpa_msg(hapd->msg_ctx, MSG_INFO, AP_EVENT_DISABLED);
 #ifdef CONFIG_FST
@@ -2366,8 +2508,15 @@ int hostapd_setup_interface_complete(struct hostapd_iface *iface, int err)
 
 	if (err) {
 		wpa_printf(MSG_ERROR, "Interface initialization failed");
-		hostapd_set_state(iface, HAPD_IFACE_DISABLED);
 		iface->need_to_start_in_sync = 0;
+
+		if (iface->is_no_ir) {
+			hostapd_set_state(iface, HAPD_IFACE_NO_IR);
+			wpa_msg(hapd->msg_ctx, MSG_INFO, AP_EVENT_NO_IR);
+			return 0;
+		}
+
+		hostapd_set_state(iface, HAPD_IFACE_DISABLED);
 		wpa_msg(hapd->msg_ctx, MSG_INFO, AP_EVENT_DISABLED);
 		if (interfaces && interfaces->terminate_on_error)
 			eloop_terminate();
@@ -2536,6 +2685,7 @@ void hostapd_interface_deinit(struct hostapd_iface *iface)
 
 	eloop_cancel_timeout(channel_list_update_timeout, iface, NULL);
 	iface->wait_channel_update = 0;
+	iface->is_no_ir = false;
 
 #ifdef CONFIG_FST
 	if (iface->fst) {
@@ -3421,6 +3571,8 @@ const char * hostapd_state_text(enum hostapd_iface_state s)
 		return "DFS";
 	case HAPD_IFACE_ENABLED:
 		return "ENABLED";
+	case HAPD_IFACE_NO_IR:
+		return "NO_IR";
 	}
 
 	return "UNKNOWN";

src/ap/hostapd.h

@@ -99,6 +99,7 @@ enum hostapd_chan_status {
 	HOSTAPD_CHAN_VALID = 0, /* channel is ready */
 	HOSTAPD_CHAN_INVALID = 1, /* no usable channel found */
 	HOSTAPD_CHAN_ACS = 2, /* ACS work being performed */
+	HOSTAPD_CHAN_INVALID_NO_IR = 3, /* channel invalid due to AFC NO IR */
 };
 
 struct hostapd_probereq_cb {
@@ -491,6 +492,7 @@ struct hostapd_iface {
 		HAPD_IFACE_ACS,
 		HAPD_IFACE_HT_SCAN,
 		HAPD_IFACE_DFS,
+		HAPD_IFACE_NO_IR,
 		HAPD_IFACE_ENABLED
 	} state;
 
@@ -650,6 +652,9 @@ struct hostapd_iface {
 
 	int (*enable_iface_cb)(struct hostapd_iface *iface);
 	int (*disable_iface_cb)(struct hostapd_iface *iface);
+
+	/* Configured freq of interface is NO_IR */
+	bool is_no_ir;
 };
 
 /* hostapd.c */

src/ap/hw_features.c

@@ -794,6 +794,11 @@ int hostapd_check_he_6ghz_capab(struct hostapd_iface *iface)
 }
 
 
+/* Returns:
+ * 1 = usable
+ * 0 = not usable
+ * -1 = not currently usable due to 6 GHz NO-IR
+ */
 static int hostapd_is_usable_chan(struct hostapd_iface *iface,
 				  int frequency, int primary)
 {
@@ -817,6 +822,10 @@ static int hostapd_is_usable_chan(struct hostapd_iface *iface,
 		   chan->flag,
 		   chan->flag & HOSTAPD_CHAN_NO_IR ? " NO-IR" : "",
 		   chan->flag & HOSTAPD_CHAN_RADAR ? " RADAR" : "");
+
+	if (is_6ghz_freq(chan->freq) && (chan->flag & HOSTAPD_CHAN_NO_IR))
+		return -1;
+
 	return 0;
 }
 
@@ -826,6 +835,7 @@ static int hostapd_is_usable_edmg(struct hostapd_iface *iface)
 	int i, contiguous = 0;
 	int num_of_enabled = 0;
 	int max_contiguous = 0;
+	int err;
 	struct ieee80211_edmg_config edmg;
 	struct hostapd_channel_data *pri_chan;
 
@@ -865,8 +875,9 @@ static int hostapd_is_usable_edmg(struct hostapd_iface *iface)
 		if (num_of_enabled > 4)
 			return 0;
 
-		if (!hostapd_is_usable_chan(iface, freq, 1))
+		err = hostapd_is_usable_chan(iface, freq, 1);
-			return 0;
+		if (err <= 0)
+			return err;
 
 		if (contiguous > max_contiguous)
 			max_contiguous = contiguous;
@@ -942,10 +953,16 @@ static bool hostapd_is_usable_punct_bitmap(struct hostapd_iface *iface)
 }
 
 
+/* Returns:
+ * 1 = usable
+ * 0 = not usable
+ * -1 = not currently usable due to 6 GHz NO-IR
+ */
 static int hostapd_is_usable_chans(struct hostapd_iface *iface)
 {
 	int secondary_freq;
 	struct hostapd_channel_data *pri_chan;
+	int err;
 
 	if (!iface->current_mode)
 		return 0;
@@ -957,12 +974,15 @@ static int hostapd_is_usable_chans(struct hostapd_iface *iface)
 		wpa_printf(MSG_ERROR, "Primary frequency not present");
 		return 0;
 	}
-	if (!hostapd_is_usable_chan(iface, pri_chan->freq, 1)) {
+
+	err = hostapd_is_usable_chan(iface, pri_chan->freq, 1);
+	if (err <= 0) {
 		wpa_printf(MSG_ERROR, "Primary frequency not allowed");
-		return 0;
+		return err;
 	}
-	if (!hostapd_is_usable_edmg(iface))
+	err = hostapd_is_usable_edmg(iface);
-		return 0;
+	if (err <= 0)
+		return err;
 
 	if (!hostapd_is_usable_punct_bitmap(iface))
 		return 0;
@@ -970,8 +990,9 @@ static int hostapd_is_usable_chans(struct hostapd_iface *iface)
 	if (!iface->conf->secondary_channel)
 		return 1;
 
-	if (hostapd_is_usable_chan(iface, iface->freq +
+	err = hostapd_is_usable_chan(iface, iface->freq +
-				   iface->conf->secondary_channel * 20, 0)) {
+				     iface->conf->secondary_channel * 20, 0);
+	if (err > 0) {
 		if (iface->conf->secondary_channel == 1 &&
 		    (pri_chan->allowed_bw & HOSTAPD_CHAN_WIDTH_40P))
 			return 1;
@@ -980,24 +1001,24 @@ static int hostapd_is_usable_chans(struct hostapd_iface *iface)
 			return 1;
 	}
 	if (!iface->conf->ht40_plus_minus_allowed)
-		return 0;
+		return err;
 
 	/* Both HT40+ and HT40- are set, pick a valid secondary channel */
 	secondary_freq = iface->freq + 20;
-	if (hostapd_is_usable_chan(iface, secondary_freq, 0) &&
+	err = hostapd_is_usable_chan(iface, secondary_freq, 0);
-	    (pri_chan->allowed_bw & HOSTAPD_CHAN_WIDTH_40P)) {
+	if (err > 0 && (pri_chan->allowed_bw & HOSTAPD_CHAN_WIDTH_40P)) {
 		iface->conf->secondary_channel = 1;
 		return 1;
 	}
 
 	secondary_freq = iface->freq - 20;
-	if (hostapd_is_usable_chan(iface, secondary_freq, 0) &&
+	err = hostapd_is_usable_chan(iface, secondary_freq, 0);
-	    (pri_chan->allowed_bw & HOSTAPD_CHAN_WIDTH_40M)) {
+	if (err > 0 && (pri_chan->allowed_bw & HOSTAPD_CHAN_WIDTH_40M)) {
 		iface->conf->secondary_channel = -1;
 		return 1;
 	}
 
-	return 0;
+	return err;
 }
 
 
@@ -1058,11 +1079,17 @@ static enum hostapd_chan_status
 hostapd_check_chans(struct hostapd_iface *iface)
 {
 	if (iface->freq) {
+		int err;
+
 		hostapd_determine_mode(iface);
-		if (hostapd_is_usable_chans(iface))
+
-			return HOSTAPD_CHAN_VALID;
+		err = hostapd_is_usable_chans(iface);
-		else
+		if (err <= 0) {
+			if (!err)
 				return HOSTAPD_CHAN_INVALID;
+			return HOSTAPD_CHAN_INVALID_NO_IR;
+		}
+		return HOSTAPD_CHAN_VALID;
 	}
 
 	/*
@@ -1073,6 +1100,8 @@ hostapd_check_chans(struct hostapd_iface *iface)
 	switch (acs_init(iface)) {
 	case HOSTAPD_CHAN_ACS:
 		return HOSTAPD_CHAN_ACS;
+	case HOSTAPD_CHAN_INVALID_NO_IR:
+		return HOSTAPD_CHAN_INVALID_NO_IR;
 	case HOSTAPD_CHAN_VALID:
 	case HOSTAPD_CHAN_INVALID:
 	default:
@@ -1112,6 +1141,7 @@ int hostapd_acs_completed(struct hostapd_iface *iface, int err)
 
 	switch (hostapd_check_chans(iface)) {
 	case HOSTAPD_CHAN_VALID:
+		iface->is_no_ir = false;
 		wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO,
 			ACS_EVENT_COMPLETED "freq=%d channel=%d",
 			iface->freq, iface->conf->channel);
@@ -1121,6 +1151,9 @@ int hostapd_acs_completed(struct hostapd_iface *iface, int err)
 		wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, ACS_EVENT_FAILED);
 		hostapd_notify_bad_chans(iface);
 		goto out;
+	case HOSTAPD_CHAN_INVALID_NO_IR:
+		iface->is_no_ir = true;
+		/* fall through */
 	case HOSTAPD_CHAN_INVALID:
 	default:
 		wpa_printf(MSG_ERROR, "ACS picked unusable channels");
@@ -1206,9 +1239,13 @@ int hostapd_select_hw_mode(struct hostapd_iface *iface)
 
 	switch (hostapd_check_chans(iface)) {
 	case HOSTAPD_CHAN_VALID:
+		iface->is_no_ir = false;
 		return 0;
 	case HOSTAPD_CHAN_ACS: /* ACS will run and later complete */
 		return 1;
+	case HOSTAPD_CHAN_INVALID_NO_IR:
+		iface->is_no_ir = true;
+		/* fall through */
 	case HOSTAPD_CHAN_INVALID:
 	default:
 		hostapd_notify_bad_chans(iface);

src/common/wpa_ctrl.h

@@ -359,6 +359,7 @@ extern "C" {
 
 #define AP_EVENT_ENABLED "AP-ENABLED "
 #define AP_EVENT_DISABLED "AP-DISABLED "
+#define AP_EVENT_NO_IR "AP-NO_IR"
 
 #define INTERFACE_ENABLED "INTERFACE-ENABLED "
 #define INTERFACE_DISABLED "INTERFACE-DISABLED "