Remove VLAN interface on STA free

Currently, vlan_remove_dynamic() is only called when the station VLAN ID
is changed (ap_sta_bind_vlan), but not when the station is freed. So
dynamic VLAN interfaces are not removed actually except within 1x
reauthentification VLAN ID change, although most of the code is already
there.

This patch fixes this by calling vlan_remove_dynamic() in ap_free_sta().

It cannot just use sta->vlan_id for this, as this might have been
changed without calling ap_sta_bind_vlan() (ap/ieee802_11.c:handle_auth
fetches from RADIUS cache for WPA-PSK), thus reference counting might
not have been updated. Additionally, reference counting might get wrong
due to old_vlanid = 0 being passed unconditionally, thus increasing the
reference counter multiple times.

So tracking the currently assigned (i.e., dynamic_vlan counter
increased) VLAN is done in a new variable sta->vlan_id_bound. Therefore,
the old_vlan_id argument of ap_sta_bind_vlan() is no longer needed and
setting the VLAN for the sta in driver happens unconditionally.

Additionally, vlan->dynamic_vlan is only incremented when it actually
is a dynamic VLAN.

Signed-off-by: Michael Braun <michael-dev@fami-braun.de>

src/ap/ieee802_11.c

@@ -2473,11 +2473,11 @@ static void handle_assoc_cb(struct hostapd_data *hapd,
 		 * so bind it to the selected VLAN interface now, since the
 		 * interface selection is not going to change anymore.
 		 */
-		if (ap_sta_bind_vlan(hapd, sta, 0) < 0)
+		if (ap_sta_bind_vlan(hapd, sta) < 0)
 			return;
 	} else if (sta->vlan_id) {
 		/* VLAN ID already set (e.g., by PMKSA caching), so bind STA */
-		if (ap_sta_bind_vlan(hapd, sta, 0) < 0)
+		if (ap_sta_bind_vlan(hapd, sta) < 0)
 			return;
 	}
 

src/ap/ieee802_1x.c

@@ -1108,8 +1108,6 @@ void ieee802_1x_new_station(struct hostapd_data *hapd, struct sta_info *sta)
 
 	pmksa = wpa_auth_sta_get_pmksa(sta->wpa_sm);
 	if (pmksa) {
-		int old_vlanid;
-
 		hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE8021X,
 			       HOSTAPD_LEVEL_DEBUG,
 			       "PMK from PMKSA cache - skip IEEE 802.1X/EAP");
@@ -1123,11 +1121,8 @@ void ieee802_1x_new_station(struct hostapd_data *hapd, struct sta_info *sta)
 		sta->eapol_sm->authFail = FALSE;
 		if (sta->eapol_sm->eap)
 			eap_sm_notify_cached(sta->eapol_sm->eap);
-		old_vlanid = sta->vlan_id;
 		pmksa_cache_to_eapol_data(pmksa, sta->eapol_sm);
-		if (sta->ssid->dynamic_vlan == DYNAMIC_VLAN_DISABLED)
-			sta->vlan_id = 0;
-		ap_sta_bind_vlan(hapd, sta, old_vlanid);
+		ap_sta_bind_vlan(hapd, sta);
 	} else {
 		if (reassoc) {
 			/*
@@ -1590,7 +1585,7 @@ ieee802_1x_receive_auth(struct radius_msg *msg, struct radius_msg *req,
 	struct hostapd_data *hapd = data;
 	struct sta_info *sta;
 	u32 session_timeout = 0, termination_action, acct_interim_interval;
-	int session_timeout_set, old_vlanid = 0, vlan_id = 0;
+	int session_timeout_set, vlan_id = 0;
 	struct eapol_state_machine *sm;
 	int override_eapReq = 0;
 	struct radius_hdr *hdr = radius_msg_get_hdr(msg);
@@ -1687,10 +1682,9 @@ ieee802_1x_receive_auth(struct radius_msg *msg, struct radius_msg *req,
 		}
 #endif /* CONFIG_NO_VLAN */
 
-		old_vlanid = sta->vlan_id;
 		sta->vlan_id = vlan_id;
 		if ((sta->flags & WLAN_STA_ASSOC) &&
-		    ap_sta_bind_vlan(hapd, sta, old_vlanid) < 0)
+		    ap_sta_bind_vlan(hapd, sta) < 0)
 			break;
 
 		sta->session_timeout_set = !!session_timeout_set;

src/ap/sta_info.c

@@ -171,6 +171,19 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
 	    !(sta->flags & WLAN_STA_PREAUTH))
 		hostapd_drv_sta_remove(hapd, sta->addr);
 
+#ifndef CONFIG_NO_VLAN
+	if (sta->vlan_id_bound) {
+		/*
+		 * Need to remove the STA entry before potentially removing the
+		 * VLAN.
+		 */
+		if (hapd->iface->driver_ap_teardown &&
+		    !(sta->flags & WLAN_STA_PREAUTH))
+			hostapd_drv_sta_remove(hapd, sta->addr);
+		vlan_remove_dynamic(hapd, sta->vlan_id_bound);
+	}
+#endif /* CONFIG_NO_VLAN */
+
 	ap_sta_hash_del(hapd, sta);
 	ap_sta_list_del(hapd, sta);
 
@@ -768,20 +781,13 @@ int ap_sta_wps_cancel(struct hostapd_data *hapd,
 #endif /* CONFIG_WPS */
 
 
-int ap_sta_bind_vlan(struct hostapd_data *hapd, struct sta_info *sta,
-		     int old_vlanid)
+int ap_sta_bind_vlan(struct hostapd_data *hapd, struct sta_info *sta)
 {
 #ifndef CONFIG_NO_VLAN
 	const char *iface;
 	struct hostapd_vlan *vlan = NULL;
 	int ret;
-
-	/*
-	 * Do not proceed furthur if the vlan id remains same. We do not want
-	 * duplicate dynamic vlan entries.
-	 */
-	if (sta->vlan_id == old_vlanid)
-		return 0;
+	int old_vlanid = sta->vlan_id_bound;
 
 	iface = hapd->conf->iface;
 	if (sta->ssid->vlan[0])
@@ -805,6 +811,14 @@ int ap_sta_bind_vlan(struct hostapd_data *hapd, struct sta_info *sta,
 			iface = vlan->ifname;
 	}
 
+	/*
+	 * Do not increment ref counters if the VLAN ID remains same, but do
+	 * not skip hostapd_drv_set_sta_vlan() as hostapd_drv_sta_remove() might
+	 * have been called before.
+	 */
+	if (sta->vlan_id == old_vlanid)
+		goto skip_counting;
+
 	if (sta->vlan_id > 0 && vlan == NULL) {
 		hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211,
 			       HOSTAPD_LEVEL_DEBUG, "could not find VLAN for "
@@ -838,7 +852,7 @@ int ap_sta_bind_vlan(struct hostapd_data *hapd, struct sta_info *sta,
 			       HOSTAPD_LEVEL_DEBUG, "added new dynamic VLAN "
 			       "interface '%s'", iface);
 	} else if (vlan && vlan->vlan_id == sta->vlan_id) {
-		if (sta->vlan_id > 0) {
+		if (vlan->dynamic_vlan > 0) {
 			vlan->dynamic_vlan++;
 			hostapd_logger(hapd, sta->addr,
 				       HOSTAPD_MODULE_IEEE80211,
@@ -862,6 +876,10 @@ int ap_sta_bind_vlan(struct hostapd_data *hapd, struct sta_info *sta,
 		}
 	}
 
+	/* ref counters have been increased, so mark the station */
+	sta->vlan_id_bound = sta->vlan_id;
+
+skip_counting:
 	hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211,
 		       HOSTAPD_LEVEL_DEBUG, "binding station to interface "
 		       "'%s'", iface);
@@ -876,10 +894,10 @@ int ap_sta_bind_vlan(struct hostapd_data *hapd, struct sta_info *sta,
 			       "entry to vlan_id=%d", sta->vlan_id);
 	}
 
-done:
 	/* During 1x reauth, if the vlan id changes, then remove the old id. */
-	if (old_vlanid > 0)
+	if (old_vlanid > 0 && old_vlanid != sta->vlan_id)
 		vlan_remove_dynamic(hapd, old_vlanid);
+done:
 
 	return ret;
 #else /* CONFIG_NO_VLAN */

src/ap/sta_info.h

@@ -121,6 +121,7 @@ struct sta_info {
 	struct hostapd_ssid *ssid_probe; /* SSID selection based on ProbeReq */
 
 	int vlan_id; /* 0: none, >0: VID */
+	int vlan_id_bound; /* updated by ap_sta_bind_vlan() */
 	 /* PSKs from RADIUS authentication server */
 	struct hostapd_sta_wpa_psk_short *psk;
 
@@ -218,8 +219,7 @@ void ap_sta_deauthenticate(struct hostapd_data *hapd, struct sta_info *sta,
 int ap_sta_wps_cancel(struct hostapd_data *hapd,
 		      struct sta_info *sta, void *ctx);
 #endif /* CONFIG_WPS */
-int ap_sta_bind_vlan(struct hostapd_data *hapd, struct sta_info *sta,
-		     int old_vlanid);
+int ap_sta_bind_vlan(struct hostapd_data *hapd, struct sta_info *sta);
 void ap_sta_start_sa_query(struct hostapd_data *hapd, struct sta_info *sta);
 void ap_sta_stop_sa_query(struct hostapd_data *hapd, struct sta_info *sta);
 int ap_check_sa_query_timeout(struct hostapd_data *hapd, struct sta_info *sta);