AP: Allow starting multiple interfaces within single MLD

Add support for including multiple hostapd interfaces in the same AP
MLD, i.e., all using the same underlying driver network interface.

To do so, when a new hostapd interface is added, if there is already
another interface using the same underlying network interface, associate
the new interface with the same private data object, instead of creating
a new one.

As some of the BSSs are non-first BSSs, meaning that they reuse the
drv_priv of the initial BSS, make sure not to double free it.

Currently multiple BSS entries are not supported so always use bss[0]
for MLD.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Ilan Peer <ilan.peer@intel.com>

hostapd/main.c

@@ -164,6 +164,59 @@ static int hostapd_driver_init(struct hostapd_iface *iface)
 		return -1;
 	}
 
+#ifdef CONFIG_IEEE80211BE
+	for (i = 0; conf->mld_ap && i < iface->interfaces->count; i++) {
+		struct hostapd_iface *h = iface->interfaces->iface[i];
+		struct hostapd_data *h_hapd = h->bss[0];
+		struct hostapd_bss_config *hconf = h_hapd->conf;
+
+		if (h == iface) {
+			wpa_printf(MSG_DEBUG, "MLD: Skip own interface");
+			continue;
+		}
+
+		if (!hconf->mld_ap || hconf->mld_id != conf->mld_id) {
+			wpa_printf(MSG_DEBUG,
+				   "MLD: Skip non matching mld_id");
+			continue;
+		}
+
+		wpa_printf(MSG_DEBUG, "MLD: Found matching MLD interface");
+		if (!h_hapd->drv_priv) {
+			wpa_printf(MSG_DEBUG,
+				   "MLD: Matching MLD BSS not initialized yet");
+			continue;
+		}
+
+		hapd->drv_priv = h_hapd->drv_priv;
+
+		/*
+		 * All interfaces participating in the AP MLD would have
+		 * the same MLD address, which is the interface hardware
+		 * address, while the interface address would be
+		 * derived from the original interface address if BSSID
+		 * is not configured, and otherwise it would be the
+		 * configured BSSID.
+		 */
+		os_memcpy(hapd->mld_addr, h_hapd->mld_addr, ETH_ALEN);
+		if (is_zero_ether_addr(b)) {
+			os_memcpy(hapd->own_addr, h_hapd->mld_addr, ETH_ALEN);
+			random_mac_addr_keep_oui(hapd->own_addr);
+		} else {
+			os_memcpy(hapd->own_addr, b, ETH_ALEN);
+		}
+
+		/*
+		 * Mark the interface as a secondary interface, as this
+		 * is needed for the de-initialization flow
+		 */
+		hapd->mld_first_bss = h_hapd;
+		hapd->mld_link_id = hapd->mld_first_bss->mld_next_link_id++;
+
+		goto setup_mld;
+	}
+#endif /* CONFIG_IEEE80211BE */
+
 	/* Initialize the driver interface */
 	if (!(b[0] | b[1] | b[2] | b[3] | b[4] | b[5]))
 		b = NULL;
@@ -214,6 +267,22 @@ static int hostapd_driver_init(struct hostapd_iface *iface)
 		return -1;
 	}
 
+#ifdef CONFIG_IEEE80211BE
+	/*
+	 * This is the first interface added to the AP MLD, so have the
+	 * interface hardware address be the MLD address and set a link address
+	 * to this interface.
+	 */
+	if (hapd->conf->mld_ap) {
+		os_memcpy(hapd->mld_addr, hapd->own_addr, ETH_ALEN);
+		random_mac_addr_keep_oui(hapd->own_addr);
+		hapd->mld_next_link_id = 0;
+		hapd->mld_link_id = hapd->mld_next_link_id++;
+	}
+
+setup_mld:
+#endif /* CONFIG_IEEE80211BE */
+
 	if (hapd->driver->get_capa &&
 	    hapd->driver->get_capa(hapd->drv_priv, &capa) == 0) {
 		struct wowlan_triggers *triggs;
@@ -248,6 +317,25 @@ static int hostapd_driver_init(struct hostapd_iface *iface)
 		iface->ema_max_periodicity = capa.ema_max_periodicity;
 	}
 
+#ifdef CONFIG_IEEE80211BE
+	if (hapd->conf->mld_ap) {
+		if (!(iface->drv_flags2 & WPA_DRIVER_FLAGS2_MLO)) {
+			wpa_printf(MSG_INFO,
+				   "MLD: Not supported by the driver");
+			return -1;
+		}
+
+		wpa_printf(MSG_DEBUG,
+			   "MLD: Set link_id=%u, mld_addr=" MACSTR
+			   ", own_addr=" MACSTR,
+			   hapd->mld_link_id, MAC2STR(hapd->mld_addr),
+			   MAC2STR(hapd->own_addr));
+
+		hostapd_drv_link_add(hapd, hapd->mld_link_id,
+				     hapd->own_addr);
+	}
+#endif /* CONFIG_IEEE80211BE */
+
 	return 0;
 }
 

src/ap/ap_drv_ops.h

@@ -441,4 +441,16 @@ hostapd_drv_register_frame(struct hostapd_data *hapd, u16 type,
 }
 #endif /* CONFIG_TESTING_OPTIONS */
 
+#ifdef CONFIG_IEEE80211BE
+static inline int hostapd_drv_link_add(struct hostapd_data *hapd,
+				       u8 link_id, const u8 *addr)
+{
+	if (!hapd->driver || !hapd->drv_priv || !hapd->driver->link_add)
+		return -1;
+
+	return hapd->driver->link_add(hapd->drv_priv, link_id, addr);
+
+}
+#endif /* CONFIG_IEEE80211BE */
+
 #endif /* AP_DRV_OPS */

src/ap/hostapd.c

@@ -393,6 +393,25 @@ static int hostapd_broadcast_wep_set(struct hostapd_data *hapd)
 #endif /* CONFIG_WEP */
 
 
+static void hostapd_clear_drv_priv(struct hostapd_data *hapd)
+{
+	unsigned int i;
+
+	for (i = 0; i < hapd->iface->interfaces->count; i++) {
+		struct hostapd_iface *iface = hapd->iface->interfaces->iface[i];
+
+		if (hapd->iface == iface)
+			continue;
+
+		if (iface->bss && iface->bss[0] &&
+		    iface->bss[0]->mld_first_bss == hapd)
+			iface->bss[0]->drv_priv = NULL;
+	}
+
+	hapd->drv_priv = NULL;
+}
+
+
 void hostapd_free_hapd_data(struct hostapd_data *hapd)
 {
 	os_free(hapd->probereq_cb);
@@ -449,7 +468,7 @@ void hostapd_free_hapd_data(struct hostapd_data *hapd)
 			 * driver wrapper may have removed its internal instance
 			 * and hapd->drv_priv is not valid anymore.
 			 */
-			hapd->drv_priv = NULL;
+			hostapd_clear_drv_priv(hapd);
 		}
 	}
 
@@ -2950,8 +2969,9 @@ void hostapd_interface_deinit_free(struct hostapd_iface *iface)
 	wpa_printf(MSG_DEBUG, "%s: driver=%p drv_priv=%p -> hapd_deinit",
 		   __func__, driver, drv_priv);
 	if (driver && driver->hapd_deinit && drv_priv) {
-		driver->hapd_deinit(drv_priv);
+		if (!iface->bss[0]->mld_first_bss)
-		iface->bss[0]->drv_priv = NULL;
+			driver->hapd_deinit(drv_priv);
+		hostapd_clear_drv_priv(iface->bss[0]);
 	}
 	hostapd_interface_free(iface);
 }
@@ -2966,13 +2986,14 @@ static void hostapd_deinit_driver(const struct wpa_driver_ops *driver,
 	wpa_printf(MSG_DEBUG, "%s: driver=%p drv_priv=%p -> hapd_deinit",
 		   __func__, driver, drv_priv);
 	if (driver && driver->hapd_deinit && drv_priv) {
-		driver->hapd_deinit(drv_priv);
+		if (!hapd_iface->bss[0]->mld_first_bss)
+			driver->hapd_deinit(drv_priv);
 		for (j = 0; j < hapd_iface->num_bss; j++) {
 			wpa_printf(MSG_DEBUG, "%s:bss[%d]->drv_priv=%p",
 				   __func__, (int) j,
 				   hapd_iface->bss[j]->drv_priv);
 			if (hapd_iface->bss[j]->drv_priv == drv_priv) {
-				hapd_iface->bss[j]->drv_priv = NULL;
+				hostapd_clear_drv_priv(hapd_iface->bss[j]);
 				hapd_iface->extended_capa = NULL;
 				hapd_iface->extended_capa_mask = NULL;
 				hapd_iface->extended_capa_len = 0;
@@ -3313,8 +3334,14 @@ int hostapd_add_iface(struct hapd_interfaces *interfaces, char *buf)
 		conf_file = ptr + 7;
 
 	for (i = 0; i < interfaces->count; i++) {
+		bool mld_ap = false;
+
+#ifdef CONFIG_IEEE80211BE
+		mld_ap = interfaces->iface[i]->conf->bss[0]->mld_ap;
+#endif /* CONFIG_IEEE80211BE */
+
 		if (!os_strcmp(interfaces->iface[i]->conf->bss[0]->iface,
-			       buf)) {
+			       buf) && !mld_ap) {
 			wpa_printf(MSG_INFO, "Cannot add interface - it "
 				   "already exists");
 			return -1;

src/ap/hostapd.h

@@ -175,6 +175,12 @@ struct hostapd_data {
 	unsigned int reenable_beacon:1;
 
 	u8 own_addr[ETH_ALEN];
+	u8 mld_addr[ETH_ALEN];
+	u8 mld_link_id;
+	/* Used for mld_link_id assignment - valid on the first MLD BSS only */
+	u8 mld_next_link_id;
+
+	struct hostapd_data *mld_first_bss;
 
 	int num_sta; /* number of entries in sta_list */
 	struct sta_info *sta_list; /* STA info list head */