P2P: Implement P2P_GO_FREQ_MOVE_SCM_ECSA policy

Add new GO frequency move policy. The P2P_GO_FREQ_MOVE_SCM_ECSA prefers
SCM if all the clients advertise eCSA support and the candidate
frequency is one of the group common frequencies.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>

src/ap/ieee802_11.c

@@ -1327,6 +1327,9 @@ static u16 check_ext_capab(struct hostapd_data *hapd, struct sta_info *sta,
 	}
 #endif /* CONFIG_INTERWORKING */
 
+	if (ext_capab_ie_len > 0)
+		sta->ecsa_supported = !!(ext_capab_ie[0] & BIT(2));
+
 	return WLAN_STATUS_SUCCESS;
 }
 

src/ap/sta_info.h

@@ -86,6 +86,7 @@ struct sta_info {
 	unsigned int hs20_deauth_requested:1;
 	unsigned int session_timeout_set:1;
 	unsigned int radius_das_match:1;
+	unsigned int ecsa_supported:1;
 
 	u16 auth_alg;
 

wpa_supplicant/config.h

@@ -761,12 +761,17 @@ struct wpa_config {
 	 * frequency list of the local device and the peer device.
 	 *
 	 * @P2P_GO_FREQ_MOVE_STAY: Prefer to stay on the current frequency.
+	 *
+	 * @P2P_GO_FREQ_MOVE_SCM_ECSA: Same as
+	 * P2P_GO_FREQ_MOVE_SCM_PEER_SUPPORTS but a transition is possible only
+	 * if all the group members advertise eCSA support.
 	 */
 	enum {
 		P2P_GO_FREQ_MOVE_SCM = 0,
 		P2P_GO_FREQ_MOVE_SCM_PEER_SUPPORTS = 1,
 		P2P_GO_FREQ_MOVE_STAY = 2,
-		P2P_GO_FREQ_MOVE_MAX = P2P_GO_FREQ_MOVE_STAY,
+		P2P_GO_FREQ_MOVE_SCM_ECSA = 3,
+		P2P_GO_FREQ_MOVE_MAX = P2P_GO_FREQ_MOVE_SCM_ECSA,
 	} p2p_go_freq_change_policy;
 
 #define DEFAULT_P2P_GO_FREQ_MOVE P2P_GO_FREQ_MOVE_STAY

wpa_supplicant/p2p_supplicant.c

@@ -2692,6 +2692,29 @@ static int wpas_p2p_go_is_peer_freq(struct wpa_supplicant *wpa_s, int freq)
 }
 
 
+static int wpas_sta_check_ecsa(struct hostapd_data *hapd,
+			       struct sta_info *sta, void *ctx)
+{
+	int *ecsa_support = ctx;
+
+	*ecsa_support &= sta->ecsa_supported;
+
+	return 0;
+}
+
+
+/* Check if all the peers support eCSA */
+static int wpas_p2p_go_clients_support_ecsa(struct wpa_supplicant *wpa_s)
+{
+	int ecsa_support = 1;
+
+	ap_for_each_sta(wpa_s->ap_iface->bss[0], wpas_sta_check_ecsa,
+			&ecsa_support);
+
+	return ecsa_support;
+}
+
+
 /**
  * Pick the best frequency to use from all the currently used frequencies.
  */
@@ -8750,6 +8773,25 @@ static void wpas_p2p_consider_moving_one_go(struct wpa_supplicant *wpa_s,
 			   P2P_GO_FREQ_MOVE_SCM_PEER_SUPPORTS &&
 			   wpas_p2p_go_is_peer_freq(wpa_s, freqs[i].freq)) {
 			policy_move = 1;
+		} else if ((wpa_s->conf->p2p_go_freq_change_policy ==
+			    P2P_GO_FREQ_MOVE_SCM_ECSA) &&
+			   wpas_p2p_go_is_peer_freq(wpa_s, freqs[i].freq)) {
+			if (!p2p_get_group_num_members(wpa_s->p2p_group)) {
+				policy_move = 1;
+			} else if ((wpa_s->drv_flags &
+				    WPA_DRIVER_FLAGS_AP_CSA) &&
+				   wpas_p2p_go_clients_support_ecsa(wpa_s)) {
+				u8 chan;
+
+				/*
+				 * We do not support CSA between bands, so move
+				 * GO only within the same band.
+				 */
+				if (wpa_s->ap_iface->current_mode->mode ==
+				    ieee80211_freq_to_chan(freqs[i].freq,
+							   &chan))
+					policy_move = 1;
+			}
 		}
 	}