P2P: Add support for automatic channel selection at GO

The driver wrapper may now indicate the preferred channel (e.g., based
on scan results) on both 2.4 GHz and 5 GHz bands (and an overall best
frequency). When setting up a GO, this preference information is used
to select the operating channel if configuration does not include
hardcoded channel. Similarly, this information can be used during
GO Negotiation to indicate preference for a specific channel based
on current channel conditions.

p2p_group_add command can now use special values (freq=2 and freq=5)
to indicate that the GO is to be started on the specified band.

src/drivers/driver.h

@@ -2229,7 +2229,16 @@ enum wpa_event_type {
 	 * resource conflicts could also trigger this for station mode
 	 * interfaces.
 	 */
-	EVENT_INTERFACE_UNAVAILABLE
+	EVENT_INTERFACE_UNAVAILABLE,
+
+	/**
+	 * EVENT_BEST_CHANNEL
+	 *
+	 * Driver generates this event whenever it detects a better channel
+	 * (e.g., based on RSSI or channel use). This information can be used
+	 * to improve channel selection for a new AP/P2P group.
+	 */
+	EVENT_BEST_CHANNEL
 };
 
 
@@ -2649,6 +2658,20 @@ union wpa_event_data {
 		int current_noise;
 		int current_txrate;
 	} signal_change;
+
+	/**
+	 * struct best_channel - Data for EVENT_BEST_CHANNEL events
+	 * @freq_24: Best 2.4 GHz band channel frequency in MHz
+	 * @freq_5: Best 5 GHz band channel frequency in MHz
+	 * @freq_overall: Best channel frequency in MHz
+	 *
+	 * 0 can be used to indicate no preference in either band.
+	 */
+	struct best_channel {
+		int freq_24;
+		int freq_5;
+		int freq_overall;
+	} best_chan;
 };
 
 /**

src/p2p/p2p.c

@@ -853,14 +853,52 @@ static int p2p_prepare_channel(struct p2p_data *p2p, unsigned int force_freq)
 		p2p->channels.reg_class[0].reg_class = p2p->op_reg_class;
 		p2p->channels.reg_class[0].channel[0] = p2p->op_channel;
 	} else {
-		p2p->op_reg_class = p2p->cfg->op_reg_class;
-		p2p->op_channel = p2p->cfg->op_channel;
+		u8 op_reg_class, op_channel;
+
+		if (!p2p->cfg->cfg_op_channel && p2p->best_freq_overall > 0 &&
+		    p2p_supported_freq(p2p, p2p->best_freq_overall) &&
+		    p2p_freq_to_channel(p2p->cfg->country,
+					p2p->best_freq_overall,
+					&op_reg_class, &op_channel) == 0) {
+			wpa_msg(p2p->cfg->msg_ctx, MSG_DEBUG,
+				"P2P: Select best overall channel as "
+				"operating channel preference");
+			p2p->op_reg_class = op_reg_class;
+			p2p->op_channel = op_channel;
+		} else if (!p2p->cfg->cfg_op_channel && p2p->best_freq_5 > 0 &&
+			   p2p_supported_freq(p2p, p2p->best_freq_5) &&
+			   p2p_freq_to_channel(p2p->cfg->country,
+					       p2p->best_freq_5,
+					       &op_reg_class, &op_channel) ==
+			   0) {
+			wpa_msg(p2p->cfg->msg_ctx, MSG_DEBUG,
+				"P2P: Select best 5 GHz channel as "
+				"operating channel preference");
+			p2p->op_reg_class = op_reg_class;
+			p2p->op_channel = op_channel;
+		} else if (!p2p->cfg->cfg_op_channel &&
+			   p2p->best_freq_24 > 0 &&
+			   p2p_supported_freq(p2p, p2p->best_freq_24) &&
+			   p2p_freq_to_channel(p2p->cfg->country,
+					       p2p->best_freq_24,
+					       &op_reg_class, &op_channel) ==
+			   0) {
+			wpa_msg(p2p->cfg->msg_ctx, MSG_DEBUG,
+				"P2P: Select best 2.4 GHz channel as "
+				"operating channel preference");
+			p2p->op_reg_class = op_reg_class;
+			p2p->op_channel = op_channel;
+		} else {
+			p2p->op_reg_class = p2p->cfg->op_reg_class;
+			p2p->op_channel = p2p->cfg->op_channel;
+		}
+
 		os_memcpy(&p2p->channels, &p2p->cfg->channels,
 			  sizeof(struct p2p_channels));
 	}
 	wpa_msg(p2p->cfg->msg_ctx, MSG_DEBUG,
 		"P2P: Own preference for operation channel: "
-		"Regulatory Class %u Channel %u%s",
+		"Operating Class %u Channel %u%s",
 		p2p->op_reg_class, p2p->op_channel,
 		force_freq ? " (forced)" : "");
 
@@ -3133,3 +3171,14 @@ int p2p_send_action(struct p2p_data *p2p, unsigned int freq, const u8 *dst,
 	return p2p->cfg->send_action(p2p->cfg->cb_ctx, freq, dst, src, bssid,
 				     buf, len, wait_time);
 }
+
+
+void p2p_set_best_channels(struct p2p_data *p2p, int freq_24, int freq_5,
+			   int freq_overall)
+{
+	wpa_msg(p2p->cfg->msg_ctx, MSG_DEBUG, "P2P: Best channel: 2.4 GHz: %d,"
+		"  5 GHz: %d,  overall: %d", freq_24, freq_5, freq_overall);
+	p2p->best_freq_24 = freq_24;
+	p2p->best_freq_5 = freq_5;
+	p2p->best_freq_overall = freq_overall;
+}

src/p2p/p2p.h

@@ -170,6 +170,11 @@ struct p2p_config {
 	 */
 	u8 op_channel;
 
+	/**
+	 * cfg_op_channel - Whether op_channel is hardcoded in configuration
+	 */
+	u8 cfg_op_channel;
+
 	/**
 	 * channels - Own supported regulatory classes and channels
 	 *
@@ -1294,4 +1299,14 @@ int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq);
 
 void p2p_update_channel_list(struct p2p_data *p2p, struct p2p_channels *chan);
 
+/**
+ * p2p_set_best_channels - Update best channel information
+ * @p2p: P2P module context from p2p_init()
+ * @freq_24: Frequency (MHz) of best channel in 2.4 GHz band
+ * @freq_5: Frequency (MHz) of best channel in 5 GHz band
+ * @freq_overall: Frequency (MHz) of best channel overall
+ */
+void p2p_set_best_channels(struct p2p_data *p2p, int freq_24, int freq_5,
+			   int freq_overall);
+
 #endif /* P2P_H */

src/p2p/p2p_i.h

@@ -383,6 +383,10 @@ struct p2p_data {
 	u8 peer_filter[ETH_ALEN];
 
 	int cross_connect;
+
+	int best_freq_24;
+	int best_freq_5;
+	int best_freq_overall;
 };
 
 /**

wpa_supplicant/events.c

@@ -1874,6 +1874,19 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 	case EVENT_INTERFACE_UNAVAILABLE:
 #ifdef CONFIG_P2P
 		wpas_p2p_interface_unavailable(wpa_s);
+#endif /* CONFIG_P2P */
+		break;
+	case EVENT_BEST_CHANNEL:
+		wpa_printf(MSG_DEBUG, "Best channel event received (%d %d %d)",
+			   data->best_chan.freq_24, data->best_chan.freq_5,
+			   data->best_chan.freq_overall);
+		wpa_s->best_24_freq = data->best_chan.freq_24;
+		wpa_s->best_5_freq = data->best_chan.freq_5;
+		wpa_s->best_overall_freq = data->best_chan.freq_overall;
+#ifdef CONFIG_P2P
+		wpas_p2p_update_best_channels(wpa_s, data->best_chan.freq_24,
+					      data->best_chan.freq_5,
+					      data->best_chan.freq_overall);
 #endif /* CONFIG_P2P */
 		break;
 	default:

wpa_supplicant/p2p_supplicant.c

@@ -2203,23 +2203,28 @@ int wpas_p2p_init(struct wpa_global *global, struct wpa_supplicant *wpa_s)
 		os_get_random((u8 *) &r, sizeof(r));
 		p2p.channel = 1 + (r % 3) * 5;
 	}
+	wpa_printf(MSG_DEBUG, "P2P: Own listen channel: %d", p2p.channel);
 
 	if (wpa_s->conf->p2p_oper_reg_class &&
 	    wpa_s->conf->p2p_oper_channel) {
 		p2p.op_reg_class = wpa_s->conf->p2p_oper_reg_class;
 		p2p.op_channel = wpa_s->conf->p2p_oper_channel;
+		p2p.cfg_op_channel = 1;
+		wpa_printf(MSG_DEBUG, "P2P: Configured operating channel: "
+			   "%d:%d", p2p.op_reg_class, p2p.op_channel);
+
 	} else {
 		p2p.op_reg_class = 81;
 		/*
-		 * For initial tests, pick the operation channel randomly.
-		 * TODO: Use scan results (etc.) to select the best channel.
+		 * Use random operation channel from (1, 6, 11) if no other
+		 * preference is indicated.
 		 */
 		os_get_random((u8 *) &r, sizeof(r));
-		p2p.op_channel = 1 + r % 11;
+		p2p.op_channel = 1 + (r % 3) * 5;
+		p2p.cfg_op_channel = 0;
+		wpa_printf(MSG_DEBUG, "P2P: Random operating channel: "
+			   "%d:%d", p2p.op_reg_class, p2p.op_channel);
 	}
-	wpa_printf(MSG_DEBUG, "P2P: Own listen channel: %d  "
-		   "Own preferred operation channel: %d",
-		   p2p.channel, p2p.op_channel);
 	if (wpa_s->conf->country[0] && wpa_s->conf->country[1]) {
 		os_memcpy(p2p.country, wpa_s->conf->country, 2);
 		p2p.country[2] = 0x04;
@@ -2865,16 +2870,48 @@ static void wpas_p2p_init_go_params(struct wpa_supplicant *wpa_s,
 
 	os_memset(params, 0, sizeof(*params));
 	params->role_go = 1;
-	params->freq = 2412;
-	if (freq)
+	if (freq) {
+		wpa_printf(MSG_DEBUG, "P2P: Set GO freq based on forced "
+			   "frequency %d MHz", freq);
 		params->freq = freq;
-	else if (wpa_s->conf->p2p_oper_reg_class == 81 &&
-		 wpa_s->conf->p2p_oper_channel >= 1 &&
-		 wpa_s->conf->p2p_oper_channel <= 11)
+	} else if (wpa_s->conf->p2p_oper_reg_class == 81 &&
+		   wpa_s->conf->p2p_oper_channel >= 1 &&
+		   wpa_s->conf->p2p_oper_channel <= 11) {
 		params->freq = 2407 + 5 * wpa_s->conf->p2p_oper_channel;
-	else if (wpa_s->conf->p2p_oper_reg_class == 115 ||
-		 wpa_s->conf->p2p_oper_reg_class == 118)
+		wpa_printf(MSG_DEBUG, "P2P: Set GO freq based on configured "
+			   "frequency %d MHz", params->freq);
+	} else if (wpa_s->conf->p2p_oper_reg_class == 115 ||
+		   wpa_s->conf->p2p_oper_reg_class == 118) {
 		params->freq = 5000 + 5 * wpa_s->conf->p2p_oper_channel;
+		wpa_printf(MSG_DEBUG, "P2P: Set GO freq based on configured "
+			   "frequency %d MHz", params->freq);
+	} else if (wpa_s->conf->p2p_oper_channel == 0 &&
+		   wpa_s->best_overall_freq > 0 &&
+		   p2p_supported_freq(wpa_s->global->p2p,
+				      wpa_s->best_overall_freq)) {
+		params->freq = wpa_s->best_overall_freq;
+		wpa_printf(MSG_DEBUG, "P2P: Set GO freq based on best overall "
+			   "channel %d MHz", params->freq);
+	} else if (wpa_s->conf->p2p_oper_channel == 0 &&
+		   wpa_s->best_24_freq > 0 &&
+		   p2p_supported_freq(wpa_s->global->p2p,
+				      wpa_s->best_24_freq)) {
+		params->freq = wpa_s->best_24_freq;
+		wpa_printf(MSG_DEBUG, "P2P: Set GO freq based on best 2.4 GHz "
+			   "channel %d MHz", params->freq);
+	} else if (wpa_s->conf->p2p_oper_channel == 0 &&
+		   wpa_s->best_5_freq > 0 &&
+		   p2p_supported_freq(wpa_s->global->p2p,
+				      wpa_s->best_5_freq)) {
+		params->freq = wpa_s->best_5_freq;
+		wpa_printf(MSG_DEBUG, "P2P: Set GO freq based on best 5 GHz "
+			   "channel %d MHz", params->freq);
+	} else {
+		params->freq = 2412;
+		wpa_printf(MSG_DEBUG, "P2P: Set GO freq %d MHz (no preference "
+			   "known)", params->freq);
+	}
+
 	if (wpa_s->current_ssid && wpa_drv_get_bssid(wpa_s, bssid) == 0 &&
 	    wpa_s->assoc_freq && !freq) {
 		wpa_printf(MSG_DEBUG, "P2P: Force GO on the channel we are "
@@ -2927,6 +2964,46 @@ int wpas_p2p_group_add(struct wpa_supplicant *wpa_s, int persistent_group,
 		       int freq)
 {
 	struct p2p_go_neg_results params;
+	unsigned int r;
+
+	if (freq == 2) {
+		wpa_printf(MSG_DEBUG, "P2P: Request to start GO on 2.4 GHz "
+			   "band");
+		if (wpa_s->best_24_freq > 0 &&
+		    p2p_supported_freq(wpa_s->global->p2p,
+				       wpa_s->best_24_freq)) {
+			freq = wpa_s->best_24_freq;
+			wpa_printf(MSG_DEBUG, "P2P: Use best 2.4 GHz band "
+				   "channel: %d MHz", freq);
+		} else {
+			os_get_random((u8 *) &r, sizeof(r));
+			freq = 2412 + (r % 3) * 25;
+			wpa_printf(MSG_DEBUG, "P2P: Use random 2.4 GHz band "
+				   "channel: %d MHz", freq);
+		}
+	}
+
+	if (freq == 5) {
+		wpa_printf(MSG_DEBUG, "P2P: Request to start GO on 5 GHz "
+			   "band");
+		if (wpa_s->best_5_freq > 0 &&
+		    p2p_supported_freq(wpa_s->global->p2p,
+				       wpa_s->best_5_freq)) {
+			freq = wpa_s->best_5_freq;
+			wpa_printf(MSG_DEBUG, "P2P: Use best 5 GHz band "
+				   "channel: %d MHz", freq);
+		} else {
+			os_get_random((u8 *) &r, sizeof(r));
+			freq = 5180 + (r % 4) * 20;
+			if (!p2p_supported_freq(wpa_s->global->p2p, freq)) {
+				wpa_printf(MSG_DEBUG, "P2P: Could not select "
+					   "5 GHz channel for P2P group");
+				return -1;
+			}
+			wpa_printf(MSG_DEBUG, "P2P: Use random 5 GHz band "
+				   "channel: %d MHz", freq);
+		}
+	}
 
 	if (freq > 0 && !p2p_supported_freq(wpa_s->global->p2p, freq)) {
 		wpa_printf(MSG_DEBUG, "P2P: The forced channel for GO "
@@ -3790,3 +3867,13 @@ void wpas_p2p_interface_unavailable(struct wpa_supplicant *wpa_s)
 	wpa_s->removal_reason = P2P_GROUP_REMOVAL_UNAVAILABLE;
 	wpas_p2p_group_delete(wpa_s);
 }
+
+
+void wpas_p2p_update_best_channels(struct wpa_supplicant *wpa_s,
+				   int freq_24, int freq_5, int freq_overall)
+{
+	struct p2p_data *p2p = wpa_s->global->p2p;
+	if (p2p == NULL || (wpa_s->drv_flags & WPA_DRIVER_FLAGS_P2P_MGMT))
+		return;
+	p2p_set_best_channels(p2p, freq_24, freq_5, freq_overall);
+}

wpa_supplicant/p2p_supplicant.h

@@ -118,5 +118,7 @@ int wpas_p2p_notif_pbc_overlap(struct wpa_supplicant *wpa_s);
 void wpas_p2p_update_channel_list(struct wpa_supplicant *wpa_s);
 int wpas_p2p_cancel(struct wpa_supplicant *wpa_s);
 void wpas_p2p_interface_unavailable(struct wpa_supplicant *wpa_s);
+void wpas_p2p_update_best_channels(struct wpa_supplicant *wpa_s,
+				   int freq_24, int freq_5, int freq_overall);
 
 #endif /* P2P_SUPPLICANT_H */

wpa_supplicant/wpa_supplicant_i.h

@@ -534,6 +534,11 @@ struct wpa_supplicant {
 	unsigned int wps_freq;
 	int wps_fragment_size;
 	int auto_reconnect_disabled;
+
+	 /* Channel preferences for AP/P2P GO use */
+	int best_24_freq;
+	int best_5_freq;
+	int best_overall_freq;
 };