P2P: DFS offload for the autonomous GO

Enhance the P2P_GROUP_ADD command to support DFS channel with 80 and 160
MHz bandwidth to be used for autonomous GO when using offloaded DFS.

For example, 'P2P_GROUP_ADD freq=5500 max_oper_chwidth=80 ht40 vht'

- Previous behavior: AP fallback to channel 100 using 20 MHz with
  "No VHT higher bandwidth support for the selected channel 100"
- Enhanced behavior: AP starts on channel 100 using 80 MHz with
  "VHT center channel 106 for 80 or 80+80 MHz bandwidth"

This functionality is on top of the driver's capability to offload DFS,
which is advertized through WPA_DRIVER_FLAGS_DFS_OFFLOAD.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

src/common/ieee802_11_common.c

@@ -1531,6 +1531,16 @@ int ieee80211_is_dfs(int freq, const struct hostapd_hw_modes *modes,
 }
 
 
+/*
+ * 802.11-2020: Table E-4 - Global operating classes
+ * DFS_50_100_Behavior: 118, 119, 120, 121, 122, 123
+ */
+int is_dfs_global_op_class(u8 op_class)
+{
+    return (op_class >= 118) && (op_class <= 123);
+}
+
+
 static int is_11b(u8 rate)
 {
 	return rate == 0x02 || rate == 0x04 || rate == 0x0b || rate == 0x16;

src/common/ieee802_11_common.h

@@ -218,6 +218,7 @@ int ieee80211_chaninfo_to_channel(unsigned int freq, enum chan_width chanwidth,
 				  int sec_channel, u8 *op_class, u8 *channel);
 int ieee80211_is_dfs(int freq, const struct hostapd_hw_modes *modes,
 		     u16 num_modes);
+int is_dfs_global_op_class(u8 op_class);
 enum phy_type ieee80211_get_phy_type(int freq, int ht, int vht);
 
 int supp_rates_11b_only(struct ieee802_11_elems *elems);

wpa_supplicant/ctrl_iface.c

@@ -6931,6 +6931,10 @@ static int p2p_ctrl_group_add(struct wpa_supplicant *wpa_s, char *cmd)
 	if (allow_6ghz && chwidth == 40)
 		max_oper_chwidth = CHANWIDTH_40MHZ_6GHZ;
 
+	/* Allow DFS to be used for Autonomous GO */
+	wpa_s->p2p_go_allow_dfs = !!(wpa_s->drv_flags &
+				     WPA_DRIVER_FLAGS_DFS_OFFLOAD);
+
 	if (group_id >= 0)
 		return p2p_ctrl_group_add_persistent(wpa_s, group_id,
 						     freq, freq2, ht40, vht,

wpa_supplicant/p2p_supplicant.c

@@ -1038,6 +1038,7 @@ static int wpas_p2p_group_delete(struct wpa_supplicant *wpa_s,
 	wpa_s->p2p_group_common_freqs = NULL;
 	wpa_s->p2p_group_common_freqs_num = 0;
 	wpa_s->p2p_go_do_acs = 0;
+	wpa_s->p2p_go_allow_dfs = 0;
 
 	wpa_s->waiting_presence_resp = 0;
 
@@ -3585,12 +3586,12 @@ static enum chan_allowed has_channel(struct wpa_global *global,
 		if ((unsigned int) mode->channels[i].freq == freq) {
 			if (flags)
 				*flags = mode->channels[i].flag;
-			if (mode->channels[i].flag &
+			if (mode->channels[i].flag & HOSTAPD_CHAN_DISABLED)
-			    (HOSTAPD_CHAN_DISABLED |
-			     HOSTAPD_CHAN_RADAR))
 				return NOT_ALLOWED;
 			if (mode->channels[i].flag & HOSTAPD_CHAN_NO_IR)
 				return NO_IR;
+			if (mode->channels[i].flag & HOSTAPD_CHAN_RADAR)
+				return RADAR;
 			return ALLOWED;
 		}
 	}
@@ -3650,7 +3651,8 @@ static enum chan_allowed wpas_p2p_verify_80mhz(struct wpa_supplicant *wpa_s,
 						chans, num_chans);
 	if (!center_chan)
 		return NOT_ALLOWED;
-	if (!is_6ghz && center_chan >= 58 && center_chan <= 138)
+	if (!wpa_s->p2p_go_allow_dfs &&
+	    !is_6ghz && center_chan >= 58 && center_chan <= 138)
 		return NOT_ALLOWED; /* Do not allow DFS channels for P2P */
 
 	/* check all the channels are available */
@@ -3661,6 +3663,8 @@ static enum chan_allowed wpas_p2p_verify_80mhz(struct wpa_supplicant *wpa_s,
 				  &flags);
 		if (res == NOT_ALLOWED)
 			return NOT_ALLOWED;
+		if (res == RADAR)
+			ret = RADAR;
 		if (res == NO_IR)
 			ret = NO_IR;
 		if (!is_6ghz) {
@@ -3742,6 +3746,8 @@ static enum chan_allowed wpas_p2p_verify_160mhz(struct wpa_supplicant *wpa_s,
 		if (res == NOT_ALLOWED)
 			return NOT_ALLOWED;
 
+		if (res == RADAR)
+			ret = RADAR;
 		if (res == NO_IR)
 			ret = NO_IR;
 
@@ -3828,6 +3834,8 @@ static enum chan_allowed wpas_p2p_verify_channel(struct wpa_supplicant *wpa_s,
 		return NOT_ALLOWED;
 	if (res == NO_IR || res2 == NO_IR)
 		return NO_IR;
+	if (res == RADAR || res2 == RADAR)
+		return RADAR;
 	return res;
 }
 
@@ -3936,7 +3944,11 @@ int wpas_p2p_get_sec_channel_offset_40mhz(struct wpa_supplicant *wpa_s,
 		u16 ch;
 		int chan = channel;
 
-		if (o->p2p == NO_P2P_SUPP ||
+		/* Allow DFS channels marked as NO_P2P_SUPP to be used with
+		 * driver offloaded DFS. */
+		if ((o->p2p == NO_P2P_SUPP &&
+		     (!is_dfs_global_op_class(o->op_class) ||
+		      !wpa_s->p2p_go_allow_dfs)) ||
 		    (is_6ghz_op_class(o->op_class) &&
 		     wpa_s->conf->p2p_6ghz_disable))
 			continue;
@@ -3959,6 +3971,11 @@ int wpas_p2p_get_sec_channel_offset_40mhz(struct wpa_supplicant *wpa_s,
 					return get_6ghz_sec_channel(channel);
 				return (o->bw == BW40MINUS) ? -1 : 1;
 			}
+			if (ret == RADAR && wpa_s->p2p_go_allow_dfs) {
+				/* Allow RADAR channels used for driver
+				 * offloaded DFS */
+				return (o->bw == BW40MINUS) ? -1 : 1;
+			}
 		}
 	}
 	return 0;
@@ -3971,8 +3988,10 @@ int wpas_p2p_get_vht80_center(struct wpa_supplicant *wpa_s,
 {
 	const u8 *chans;
 	size_t num_chans;
+	enum chan_allowed ret;
 
-	if (!wpas_p2p_verify_channel(wpa_s, mode, op_class, channel, BW80))
+	ret = wpas_p2p_verify_channel(wpa_s, mode, op_class, channel, BW80);
+	if (!(ret == ALLOWED || (ret == RADAR && wpa_s->p2p_go_allow_dfs)))
 		return 0;
 
 	if (is_6ghz_op_class(op_class)) {
@@ -3993,8 +4012,10 @@ int wpas_p2p_get_vht160_center(struct wpa_supplicant *wpa_s,
 {
 	const u8 *chans;
 	size_t num_chans;
+	enum chan_allowed ret;
 
-	if (!wpas_p2p_verify_channel(wpa_s, mode, op_class, channel, BW160))
+	ret = wpas_p2p_verify_channel(wpa_s, mode, op_class, channel, BW160);
+	if (!(ret == ALLOWED || (ret == RADAR && wpa_s->p2p_go_allow_dfs)))
 		return 0;
 	if (is_6ghz_op_class(op_class)) {
 		chans = center_channels_6ghz_160mhz;
@@ -6766,6 +6787,11 @@ wpas_p2p_get_group_iface(struct wpa_supplicant *wpa_s, int addr_allocated,
 		wpa_s->p2p_go_do_acs = 0;
 	}
 
+	if (go && wpa_s->p2p_go_allow_dfs) {
+		group_wpa_s->p2p_go_allow_dfs = wpa_s->p2p_go_allow_dfs;
+		wpa_s->p2p_go_allow_dfs = 0;
+	}
+
 	wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Use separate group interface %s",
 		group_wpa_s->ifname);
 	group_wpa_s->p2p_first_connection_timeout = 0;

wpa_supplicant/wpa_supplicant_i.h

@@ -1125,6 +1125,7 @@ struct wpa_supplicant {
 	unsigned int p2p_disable_ip_addr_req:1;
 	unsigned int p2ps_method_config_any:1;
 	unsigned int p2p_cli_probe:1;
+	unsigned int p2p_go_allow_dfs:1;
 	enum hostapd_hw_mode p2p_go_acs_band;
 	int p2p_persistent_go_freq;
 	int p2p_persistent_id;
@@ -1675,7 +1676,7 @@ void wpas_update_mbo_connect_params(struct wpa_supplicant *wpa_s);
 
 /* op_classes.c */
 enum chan_allowed {
-	NOT_ALLOWED, NO_IR, ALLOWED
+	NOT_ALLOWED, NO_IR, RADAR, ALLOWED
 };
 
 enum chan_allowed verify_channel(struct hostapd_hw_modes *mode, u8 op_class,