hostap: add channel switch ability to AP & GO (INTERNAL)

Add channel switch command and handle channel switch
request/complete events.

New hostapd_eid_csa() which builds the channel switch
announcement IE. Add this CSA to the beacon frame prior
performing a channel switch and remove it once it's
completed.

New EVENT_REQ_CH_SW which indicates that the driver
has requested to perform a channel switch.

Signed-hostap: Victor Goldenshtein <victorg@ti.com>

9 files changed, 150 insertions, 3 deletions

diff --git a/src/ap/beacon.c b/src/ap/beacon.c
index a1bb067..72c3ead 100644
--- a/src/ap/beacon.c
+++ b/src/ap/beacon.c
@@ -33,6 +33,7 @@
 #include "p2p_hostapd.h"
 #include "ap_drv_ops.h"
 #include "beacon.h"
+#include "hw_features.h"
 
 
 #ifdef NEED_AP_MLME
@@ -171,6 +172,27 @@ static u8 * hostapd_eid_country(struct hostapd_data *hapd, u8 *eid,
 	return pos;
 }
 
+static u8 *hostapd_eid_csa(struct hostapd_data *hapd, u8 *eid)
+{
+	int current_ch_flag = 0;
+
+	if (!hapd->next_channel)
+		return eid;
+
+	current_ch_flag = hostapd_hw_get_channel_flag(hapd,
+						      hapd->iconf->channel);
+
+	*eid++ = WLAN_EID_CHANNEL_SWITCH;
+	*eid++ = 3; /* IE length */
+	/* STAs should cease transmit if the switch is due to radar */
+	*eid++ = (current_ch_flag & HOSTAPD_CHAN_RADAR) ? 1 : 0;
+	*eid++ = (u8)hapd->next_channel->chan;
+	*eid++ = (hapd->iconf->channel_switch_count > hapd->conf->dtim_period) ?
+		(u8)hapd->iconf->channel_switch_count :
+		hapd->conf->dtim_period * 2;
+	return eid;
+}
+
 
 static u8 * hostapd_eid_wpa(struct hostapd_data *hapd, u8 *eid, size_t len)
 {
@@ -573,6 +595,9 @@ void ieee802_11_set_beacon(struct hostapd_data *hapd)
 	tailpos = hostapd_eid_country(hapd, tailpos,
 				      tail + BEACON_TAIL_BUF_SIZE - tailpos);
 
+	/* Channel Switch Announcement */
+	tailpos = hostapd_eid_csa(hapd, tailpos);
+
 	/* ERP Information element */
 	tailpos = hostapd_eid_erp_info(hapd, tailpos);
 
diff --git a/src/ap/drv_callbacks.c b/src/ap/drv_callbacks.c
index f80a08c..7e478a5 100644
--- a/src/ap/drv_callbacks.c
+++ b/src/ap/drv_callbacks.c
@@ -27,6 +27,7 @@
 #include "ap_drv_ops.h"
 #include "ap_config.h"
 #include "hw_features.h"
+#include "beacon.h"
 
 
 int hostapd_notif_assoc(struct hostapd_data *hapd, const u8 *addr,
@@ -286,8 +287,6 @@ void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
 		       HOSTAPD_LEVEL_INFO, "driver had channel switch: "
 		       "freq=%d, ht=%d, offset=%d", freq, ht, offset);
 
-	hapd->iface->freq = freq;
-
 	channel = hostapd_hw_get_channel(hapd, freq);
 	if (!channel) {
 		hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
@@ -299,6 +298,30 @@ void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
 	hapd->iconf->channel = channel;
 	hapd->iconf->ieee80211n = ht;
 	hapd->iconf->secondary_channel = offset;
+
+
+	if (hapd->iface->freq == freq)
+	        return;
+
+	hapd->iface->freq = freq;
+
+	if (hostapd_set_freq(hapd, hapd->iconf->hw_mode, freq,
+			     hapd->iconf->channel,
+			     hapd->iconf->ieee80211n,
+			     hapd->iconf->secondary_channel)) {
+		hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
+			       HOSTAPD_LEVEL_WARNING,
+			       "failed to update the freq !");
+		return;
+	}
+
+	hapd->next_channel = NULL;
+
+	/* update the DS IE */
+	ieee802_11_set_beacon(hapd);
+
+	wpa_printf(MSG_DEBUG, "AP/GO moved to channel %d", channel);
+
 #endif /* NEED_AP_MLME */
 }
 
@@ -627,6 +650,12 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 					data->ch_switch.ht_enabled,
 					data->ch_switch.ch_offset);
 		break;
+	case EVENT_REQ_CH_SW:
+		if (!data)
+			break;
+		ieee802_11_start_channel_switch(hapd, data->ch_switch.freq,
+						FALSE);
+		break;
 	default:
 		wpa_printf(MSG_DEBUG, "Unknown event %d", event);
 		break;
diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index 3406cd1..4e06808 100644
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -1106,3 +1106,34 @@ void hostapd_new_assoc_sta(struct hostapd_data *hapd, struct sta_info *sta,
 	eloop_register_timeout(hapd->conf->ap_max_inactivity, 0,
 			       ap_handle_timer, hapd, sta);
 }
+
+struct
+hostapd_channel_data *hostapd_get_valid_channel(struct hostapd_data *hapd,
+						int req_freq)
+{
+	struct hostapd_hw_modes *mode;
+	struct hostapd_channel_data *chan;
+	int i, channel_idx = 0;
+
+	wpa_printf(MSG_DEBUG, "Selecting next channel");
+
+	if (hapd->iface->current_mode == NULL)
+		return NULL;
+
+	mode = hapd->iface->current_mode;
+
+	for (i = 0; i < mode->num_channels; i++) {
+		chan = &mode->channels[i];
+
+		if (chan->flag & (HOSTAPD_CHAN_DISABLED | HOSTAPD_CHAN_RADAR))
+			continue;
+		channel_idx++;
+
+		/* request specific channel */
+		if (req_freq && (req_freq == chan->freq))
+			return chan;
+	}
+
+	wpa_printf(MSG_WARNING, "Could't get requested channel");
+	return NULL;
+}
diff --git a/src/ap/hostapd.h b/src/ap/hostapd.h
index 0465844..feea42d 100644
--- a/src/ap/hostapd.h
+++ b/src/ap/hostapd.h
@@ -162,6 +162,8 @@ struct hostapd_data {
 	void (*setup_complete_cb)(void *ctx);
 	void *setup_complete_cb_ctx;
 
+	struct hostapd_channel_data *next_channel;
+
 #ifdef CONFIG_P2P
 	struct p2p_data *p2p;
 	struct p2p_group *p2p_group;
@@ -271,6 +273,9 @@ void hostapd_interface_deinit(struct hostapd_iface *iface);
 void hostapd_interface_free(struct hostapd_iface *iface);
 void hostapd_new_assoc_sta(struct hostapd_data *hapd, struct sta_info *sta,
 			   int reassoc);
+struct
+hostapd_channel_data *hostapd_get_valid_channel(struct hostapd_data *hapd,
+						int req_freq);
 
 /* utils.c */
 int hostapd_register_probereq_cb(struct hostapd_data *hapd,
diff --git a/src/ap/hw_features.c b/src/ap/hw_features.c
index 0900e78..930d35b 100644
--- a/src/ap/hw_features.c
+++ b/src/ap/hw_features.c
@@ -796,3 +796,21 @@ int hostapd_hw_get_channel(struct hostapd_data *hapd, int freq)
 
 	return 0;
 }
+
+
+int hostapd_hw_get_channel_flag(struct hostapd_data *hapd, int chan)
+{
+	int i;
+
+	if (!hapd->iface->current_mode)
+		return 0;
+
+	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
+		struct hostapd_channel_data *ch =
+			&hapd->iface->current_mode->channels[i];
+		if (ch->chan == chan)
+			return ch->flag;
+	}
+
+	return 0;
+}
diff --git a/src/ap/hw_features.h b/src/ap/hw_features.h
index abadcd1..b8e287b 100644
--- a/src/ap/hw_features.h
+++ b/src/ap/hw_features.h
@@ -28,6 +28,7 @@ int hostapd_hw_get_channel(struct hostapd_data *hapd, int freq);
 int hostapd_check_ht_capab(struct hostapd_iface *iface);
 int hostapd_prepare_rates(struct hostapd_iface *iface,
 			  struct hostapd_hw_modes *mode);
+int hostapd_hw_get_channel_flag(struct hostapd_data *hapd, int chan);
 #else /* NEED_AP_MLME */
 static inline void
 hostapd_free_hw_features(struct hostapd_hw_modes *hw_features,
diff --git a/src/ap/ieee802_11.c b/src/ap/ieee802_11.c
index ed1661a..0b23561 100644
--- a/src/ap/ieee802_11.c
+++ b/src/ap/ieee802_11.c
@@ -1889,4 +1889,34 @@ void ieee802_11_rx_from_unknown(struct hostapd_data *hapd, const u8 *src,
 }
 
 
+int ieee802_11_start_channel_switch(struct hostapd_data *hapd,
+				    int freq, u8 radar_detected)
+{
+	struct hostapd_channel_data *next_channel;
+
+	next_channel = hostapd_get_valid_channel(hapd, freq);
+	if (!next_channel)
+		return -1;
+
+	hapd->next_channel = next_channel;
+	u8 radar_on_next_channel =
+		(next_channel->flag & HOSTAPD_CHAN_RADAR) ? 1 : 0;
+	wpa_printf(MSG_INFO, "switching to %sch. #%d, freq %d",
+		   radar_on_next_channel ? "(DFS) " : "",
+		   next_channel->chan, next_channel->freq);
+
+	/* Add CSA */
+	ieee802_11_set_beacon(hapd);
+
+	if (hostapd_channel_switch(hapd, next_channel->freq,
+				   next_channel->flag,
+				   radar_detected,
+				   radar_on_next_channel)) {
+		wpa_printf(MSG_ERROR, "Channel switch failed");
+		return -1;
+	}
+	return 0;
+}
+
+
 #endif /* CONFIG_NATIVE_WINDOWS */
diff --git a/src/drivers/driver.h b/src/drivers/driver.h
index b25b4b9..6446593 100644
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -3060,7 +3060,12 @@ enum wpa_event_type {
 	 *
 	 * Described in wpa_event_data.ch_switch
 	 * */
-	EVENT_CH_SWITCH
+	EVENT_CH_SWITCH,
+
+	/**
+	 * EVENT_REQ_CH_SW - a request to perform a channel switch for GO/AP
+	 */
+	EVENT_REQ_CH_SW
 };
 
 
@@ -3723,6 +3728,8 @@ static inline void drv_event_eapol_rx(void *ctx, const u8 *src, const u8 *data,
 
 /* driver_common.c */
 void wpa_scan_results_free(struct wpa_scan_results *res);
+int ieee802_11_start_channel_switch(struct hostapd_data *hapd,
+				    int freq, u8 radar_detected);
 
 /* Convert wpa_event_type to a string for logging */
 const char * event_to_string(enum wpa_event_type event);
diff --git a/src/drivers/driver_common.c b/src/drivers/driver_common.c
index 5e4dc89..a0ada97 100644
--- a/src/drivers/driver_common.c
+++ b/src/drivers/driver_common.c
@@ -82,6 +82,7 @@ const char * event_to_string(enum wpa_event_type event)
 	E2S(ROAMING_ENABLED);
 	E2S(ROAMING_DISABLED);
 	E2S(START_ROAMING);
+	E2S(REQ_CH_SW);
 	}
 
 	return "UNKNOWN";