hostapd: Add WDS (4-address frame) mode with per-station interfaces

This mode allows associated stations to use 4-address frames to allow
layer 2 bridging to be used. At least for the time being, this is only
supported with driver=nl80211.

hostapd/config.c

@@ -1534,6 +1534,8 @@ struct hostapd_config * hostapd_config_read(const char *fname)
 					   line, pos);
 				errors++;
 			}
+		} else if (os_strcmp(buf, "wds_sta") == 0) {
+			bss->wds_sta = atoi(pos);
 		} else if (os_strcmp(buf, "ap_max_inactivity") == 0) {
 			bss->ap_max_inactivity = atoi(pos);
 		} else if (os_strcmp(buf, "country_code") == 0) {

hostapd/config.h

@@ -194,6 +194,7 @@ struct hostapd_bss_config {
 	int num_accept_mac;
 	struct mac_acl_entry *deny_mac;
 	int num_deny_mac;
+	int wds_sta;
 
 	int auth_algs; /* bitfield of allowed IEEE 802.11 authentication
 			* algorithms, WPA_AUTH_ALG_{OPEN,SHARED,LEAP} */

hostapd/driver_i.h

@@ -399,6 +399,15 @@ hostapd_set_sta_vlan(const char *ifname, struct hostapd_data *hapd,
 	return hapd->driver->set_sta_vlan(hapd->drv_priv, addr, ifname, vlan_id);
 }
 
+static inline int
+hostapd_set_wds_sta(struct hostapd_data *hapd, const u8 *addr, int aid,
+		    int val)
+{
+	if (hapd->driver == NULL || hapd->driver->set_wds_sta == NULL)
+		return 0;
+	return hapd->driver->set_wds_sta(hapd->drv_priv, addr, aid, val);
+}
+
 static inline int
 hostapd_driver_commit(struct hostapd_data *hapd)
 {

hostapd/drv_callbacks.c

@@ -299,6 +299,7 @@ static const u8 * get_hdr_bssid(const struct ieee80211_hdr *hdr, size_t len)
 		if (len < 24)
 			return NULL;
 		switch (fc & (WLAN_FC_FROMDS | WLAN_FC_TODS)) {
+		case WLAN_FC_FROMDS | WLAN_FC_TODS:
 		case WLAN_FC_TODS:
 			return hdr->addr1;
 		case WLAN_FC_FROMDS:
@@ -344,11 +345,14 @@ static void hostapd_rx_from_unknown_sta(struct hostapd_data *hapd,
 					const struct ieee80211_hdr *hdr,
 					size_t len)
 {
+	u16 fc = le_to_host16(hdr->frame_control);
 	hapd = get_hapd_bssid(hapd->iface, get_hdr_bssid(hdr, len));
 	if (hapd == NULL || hapd == HAPD_BROADCAST)
 		return;
 
-	ieee802_11_rx_from_unknown(hapd, hdr->addr2);
+	ieee802_11_rx_from_unknown(hapd, hdr->addr2,
+				   (fc & (WLAN_FC_TODS | WLAN_FC_FROMDS)) ==
+				   (WLAN_FC_TODS | WLAN_FC_FROMDS));
 }
 
 

hostapd/dump_state.c

@@ -106,7 +106,7 @@ static void hostapd_dump_state(struct hostapd_data *hapd)
 		fprintf(f, "\nSTA=" MACSTR "\n", MAC2STR(sta->addr));
 
 		fprintf(f,
-			"  AID=%d flags=0x%x %s%s%s%s%s%s%s%s%s%s%s%s%s%s\n"
+			"  AID=%d flags=0x%x %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n"
 			"  capability=0x%x listen_interval=%d\n",
 			sta->aid,
 			sta->flags,
@@ -126,6 +126,7 @@ static void hostapd_dump_state(struct hostapd_data *hapd)
 			(sta->flags & WLAN_STA_MFP ? "[MFP]" : ""),
 			(sta->flags & WLAN_STA_WPS ? "[WPS]" : ""),
 			(sta->flags & WLAN_STA_MAYBE_WPS ? "[MAYBE_WPS]" : ""),
+			(sta->flags & WLAN_STA_WDS ? "[WDS]" : ""),
 			(sta->flags & WLAN_STA_NONERP ? "[NonERP]" : ""),
 			sta->capability,
 			sta->listen_interval);

hostapd/hostapd.conf

@@ -346,6 +346,12 @@ wmm_ac_vo_acm=0
 # remain asleep). Default: 65535 (no limit apart from field size)
 #max_listen_interval=100
 
+# WDS (4-address frame) mode with per-station virtual interfaces
+# (only supported with driver=nl80211)
+# This mode allows associated stations to use 4-address frames to allow layer 2
+# bridging to be used.
+#wds_sta=1
+
 ##### IEEE 802.11n related configuration ######################################
 
 # ieee80211n: Whether IEEE 802.11n (HT) is enabled

hostapd/ieee802_11.c

@@ -1689,13 +1689,22 @@ void hostapd_tx_status(struct hostapd_data *hapd, const u8 *addr,
 }
 
 
-void ieee802_11_rx_from_unknown(struct hostapd_data *hapd, const u8 *src)
+void ieee802_11_rx_from_unknown(struct hostapd_data *hapd, const u8 *src,
+				int wds)
 {
 	struct sta_info *sta;
 
 	sta = ap_get_sta(hapd, src);
-	if (sta && (sta->flags & WLAN_STA_ASSOC))
+	if (sta && (sta->flags & WLAN_STA_ASSOC)) {
+		if (wds && !(sta->flags & WLAN_STA_WDS)) {
+			wpa_printf(MSG_DEBUG, "Enable 4-address WDS mode for "
+				   "STA " MACSTR " (aid %u)",
+				   MAC2STR(sta->addr), sta->aid);
+			sta->flags |= WLAN_STA_WDS;
+			hostapd_set_wds_sta(hapd, sta->addr, sta->aid, 1);
+		}
 		return;
+	}
 
 	wpa_printf(MSG_DEBUG, "Data/PS-poll frame from not associated STA "
 		   MACSTR, MAC2STR(src));

hostapd/ieee802_11.h

@@ -65,6 +65,7 @@ u16 copy_sta_ht_capab(struct sta_info *sta, const u8 *ht_capab,
 void update_ht_state(struct hostapd_data *hapd, struct sta_info *sta);
 void hostapd_tx_status(struct hostapd_data *hapd, const u8 *addr,
 		       const u8 *buf, size_t len, int ack);
-void ieee802_11_rx_from_unknown(struct hostapd_data *hapd, const u8 *src);
+void ieee802_11_rx_from_unknown(struct hostapd_data *hapd, const u8 *src,
+				int wds);
 
 #endif /* IEEE802_11_H */

hostapd/sta_info.c

@@ -120,6 +120,7 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
 
 	accounting_sta_stop(hapd, sta);
 
+	hostapd_set_wds_sta(hapd, sta->addr, sta->aid, 0);
 	if (!ap_sta_in_other_bss(hapd, sta, WLAN_STA_ASSOC) &&
 	    !(sta->flags & WLAN_STA_PREAUTH))
 		hostapd_sta_remove(hapd, sta->addr);

hostapd/sta_info.h

@@ -30,6 +30,7 @@
 #define WLAN_STA_HT BIT(11)
 #define WLAN_STA_WPS BIT(12)
 #define WLAN_STA_MAYBE_WPS BIT(13)
+#define WLAN_STA_WDS BIT(14)
 #define WLAN_STA_NONERP BIT(31)
 
 /* Maximum number of supported rates (from both Supported Rates and Extended

src/drivers/driver.h

@@ -1527,6 +1527,16 @@ struct wpa_driver_ops {
 	 * Returns: 0 on success, -1 on failure
 	 */
 	int (*set_supp_port)(void *priv, int authorized);
+
+	/**
+	 * set_wds_sta - Bind a station into a 4-address WDS (AP only)
+	 * @priv: Private driver interface data
+	 * @addr: MAC address of the associated station
+	 * @aid: Association ID
+	 * @val: 1 = bind to 4-address WDS; 0 = unbind
+	 * Returns: 0 on success, -1 on failure
+	 */
+	int (*set_wds_sta)(void *priv, const u8 *addr, int aid, int val);
 };
 
 /**

src/drivers/driver_ndis.c

@@ -3244,5 +3244,6 @@ const struct wpa_driver_ops wpa_driver_ndis_ops = {
 	NULL /* set_ht_params */,
 	NULL /* set_wps_beacon_ie */,
 	NULL /* set_wps_probe_resp_ie */,
-	NULL /* set_supp_port */
+	NULL /* set_supp_port */,
+	NULL /* set_wds_sta */
 };

src/drivers/driver_nl80211.c

@@ -128,6 +128,9 @@ static void del_ifidx(struct wpa_driver_nl80211_data *drv, int ifidx);
 static struct i802_bss * get_bss(struct wpa_driver_nl80211_data *drv,
 				 int ifindex);
 static int i802_set_freq(void *priv, struct hostapd_freq_params *freq);
+static int wpa_driver_nl80211_if_remove(void *priv,
+					enum wpa_driver_if_type type,
+					const char *ifname);
 #endif /* HOSTAPD */
 
 
@@ -2553,7 +2556,7 @@ static void nl80211_remove_iface(struct wpa_driver_nl80211_data *drv,
 static int nl80211_create_iface_once(struct wpa_driver_nl80211_data *drv,
 				     const char *ifname,
 				     enum nl80211_iftype iftype,
-				     const u8 *addr)
+				     const u8 *addr, int wds)
 {
 	struct nl_msg *msg, *flags = NULL;
 	int ifidx;
@@ -2584,6 +2587,8 @@ static int nl80211_create_iface_once(struct wpa_driver_nl80211_data *drv,
 
 		if (err)
 			goto nla_put_failure;
+	} else if (wds) {
+		NLA_PUT_U8(msg, NL80211_ATTR_4ADDR, wds);
 	}
 
 	ret = send_and_recv_msgs(drv, msg, NULL, NULL);
@@ -2616,11 +2621,11 @@ static int nl80211_create_iface_once(struct wpa_driver_nl80211_data *drv,
 
 static int nl80211_create_iface(struct wpa_driver_nl80211_data *drv,
 				const char *ifname, enum nl80211_iftype iftype,
-				const u8 *addr)
+				const u8 *addr, int wds)
 {
 	int ret;
 
-	ret = nl80211_create_iface_once(drv, ifname, iftype, addr);
+	ret = nl80211_create_iface_once(drv, ifname, iftype, addr, wds);
 
 	/* if error occured and interface exists already */
 	if (ret == -ENFILE && if_nametoindex(ifname)) {
@@ -2630,7 +2635,8 @@ static int nl80211_create_iface(struct wpa_driver_nl80211_data *drv,
 		nl80211_remove_iface(drv, if_nametoindex(ifname));
 
 		/* Try to create the interface again */
-		ret = nl80211_create_iface_once(drv, ifname, iftype, addr);
+		ret = nl80211_create_iface_once(drv, ifname, iftype, addr,
+						wds);
 	}
 
 	return ret;
@@ -2817,7 +2823,7 @@ static struct sock_filter msock_filter_insns[] = {
 
 #if 0
 	/*
-	 * drop non-data frames, WDS frames
+	 * drop non-data frames
 	 */
 	/* load the lower byte of the frame control field */
 	BPF_STMT(BPF_LD   | BPF_B | BPF_IND, 0),
@@ -2825,13 +2831,13 @@ static struct sock_filter msock_filter_insns[] = {
 	BPF_STMT(BPF_ALU  | BPF_AND | BPF_K, 0x0c),
 	/* drop non-data frames */
 	BPF_JUMP(BPF_JMP  | BPF_JEQ | BPF_K, 8, 0, FAIL),
+#endif
 	/* load the upper byte of the frame control field */
-	BPF_STMT(BPF_LD   | BPF_B | BPF_IND, 0),
+	BPF_STMT(BPF_LD   | BPF_B | BPF_IND, 1),
 	/* mask off toDS/fromDS */
 	BPF_STMT(BPF_ALU  | BPF_AND | BPF_K, 0x03),
-	/* drop WDS frames */
-	BPF_JUMP(BPF_JMP  | BPF_JEQ | BPF_K, 3, FAIL, 0),
-#endif
+	/* accept WDS frames */
+	BPF_JUMP(BPF_JMP  | BPF_JEQ | BPF_K, 3, PASS, 0),
 
 	/*
 	 * add header length to index
@@ -2937,7 +2943,8 @@ nl80211_create_monitor_interface(struct wpa_driver_nl80211_data *drv)
 	buf[IFNAMSIZ - 1] = '\0';
 
 	drv->monitor_ifidx =
-		nl80211_create_iface(drv, buf, NL80211_IFTYPE_MONITOR, NULL);
+		nl80211_create_iface(drv, buf, NL80211_IFTYPE_MONITOR, NULL,
+				     0);
 
 	if (drv->monitor_ifidx < 0)
 		return -1;
@@ -4065,6 +4072,26 @@ static int i802_set_sta_vlan(void *priv, const u8 *addr,
 }
 
 
+static int i802_set_wds_sta(void *priv, const u8 *addr, int aid, int val)
+{
+	struct wpa_driver_nl80211_data *drv = priv;
+	char name[16];
+
+	os_snprintf(name, sizeof(name), "%s.sta%d", drv->ifname, aid);
+	if (val) {
+		if (nl80211_create_iface(priv, name, NL80211_IFTYPE_AP_VLAN,
+					 NULL, 1) < 0)
+			return -1;
+		hostapd_set_iface_flags(drv, name, 1);
+		return i802_set_sta_vlan(priv, addr, name, 0);
+	} else {
+		i802_set_sta_vlan(priv, addr, drv->ifname, 0);
+		return wpa_driver_nl80211_if_remove(priv, WPA_IF_AP_VLAN,
+						    name);
+	}
+}
+
+
 static void handle_eapol(int sock, void *eloop_ctx, void *sock_ctx)
 {
 	struct wpa_driver_nl80211_data *drv = eloop_ctx;
@@ -4262,7 +4289,8 @@ static int wpa_driver_nl80211_if_add(const char *iface, void *priv,
 #endif /* HOSTAPD */
 
 	ifidx = nl80211_create_iface(drv, ifname,
-				     wpa_driver_nl80211_if_type(type), addr);
+				     wpa_driver_nl80211_if_type(type), addr,
+				     0);
 	if (ifidx < 0) {
 #ifdef HOSTAPD
 		os_free(bss);
@@ -4363,5 +4391,6 @@ const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 	.set_short_slot_time = i802_set_short_slot_time,
 	.set_tx_queue_params = i802_set_tx_queue_params,
 	.set_sta_vlan = i802_set_sta_vlan,
+	.set_wds_sta = i802_set_wds_sta,
 #endif /* HOSTAPD */
 };

wpa_supplicant/ap.c

@@ -507,7 +507,10 @@ void ap_rx_from_unknown_sta(void *ctx, const struct ieee80211_hdr *hdr,
 {
 #ifdef NEED_AP_MLME
 	struct wpa_supplicant *wpa_s = ctx;
-	ieee802_11_rx_from_unknown(wpa_s->ap_iface->bss[0], hdr->addr2);
+	u16 fc = le_to_host16(hdr->frame_control);
+	ieee802_11_rx_from_unknown(wpa_s->ap_iface->bss[0], hdr->addr2,
+				   (fc & (WLAN_FC_TODS | WLAN_FC_FROMDS)) ==
+				   (WLAN_FC_TODS | WLAN_FC_FROMDS));
 #endif /* NEED_AP_MLME */
 }