hostapd: Fix interface selection for the nl80211 driver

This patch allows the nl80211 driver to create its own per-bss context
and pass it to the drv_priv pointer of the hostapd bss state.
With this and the following patch, stations can associate to and switch
between multiple BSS interfaces of a single wiphy.
This obsoletes a few instances of passing ifname to a callback, those
can be removed in a separate patch.
It might also be useful to move more fields from the driver data to the
per-bss data structure in the future.

src/ap/ap_drv_ops.c

@@ -242,7 +242,7 @@ static int hostapd_set_beacon(const char *ifname, struct hostapd_data *hapd,
 
 static int hostapd_vlan_if_add(struct hostapd_data *hapd, const char *ifname)
 {
-	return hostapd_if_add(hapd, WPA_IF_AP_VLAN, ifname, NULL, NULL);
+	return hostapd_if_add(hapd, WPA_IF_AP_VLAN, ifname, NULL, NULL, NULL);
 }
 
 static int hostapd_vlan_if_remove(struct hostapd_data *hapd,
@@ -407,12 +407,13 @@ int hostapd_set_ssid(struct hostapd_data *hapd, const u8 *buf, size_t len)
 
 
 int hostapd_if_add(struct hostapd_data *hapd, enum wpa_driver_if_type type,
-		   const char *ifname, const u8 *addr, void *bss_ctx)
+		   const char *ifname, const u8 *addr, void *bss_ctx,
+		   void **drv_priv)
 {
 	if (hapd->driver == NULL || hapd->driver->if_add == NULL)
 		return -1;
 	return hapd->driver->if_add(hapd->conf->iface, hapd->drv_priv, type,
-				    ifname, addr, bss_ctx);
+				    ifname, addr, bss_ctx, drv_priv);
 }
 
 

src/ap/ap_drv_ops.h

@@ -26,7 +26,8 @@ int hostapd_set_generic_elem(struct hostapd_data *hapd, const u8 *elem,
 int hostapd_get_ssid(struct hostapd_data *hapd, u8 *buf, size_t len);
 int hostapd_set_ssid(struct hostapd_data *hapd, const u8 *buf, size_t len);
 int hostapd_if_add(struct hostapd_data *hapd, enum wpa_driver_if_type type,
-		   const char *ifname, const u8 *addr, void *bss_ctx);
+		   const char *ifname, const u8 *addr, void *bss_ctx,
+		   void **drv_priv);
 int hostapd_if_remove(struct hostapd_data *hapd, enum wpa_driver_if_type type,
 		      const char *ifname);
 int hostapd_set_ieee8021x(struct hostapd_data *hapd,

src/ap/hostapd.c

@@ -484,7 +484,8 @@ static int hostapd_setup_bss(struct hostapd_data *hapd, int first)
 
 		hapd->interface_added = 1;
 		if (hostapd_if_add(hapd->iface->bss[0], WPA_IF_AP_BSS,
-				   hapd->conf->iface, hapd->own_addr, hapd)) {
+				   hapd->conf->iface, hapd->own_addr, hapd,
+				   &hapd->drv_priv)) {
 			wpa_printf(MSG_ERROR, "Failed to add BSS (BSSID="
 				   MACSTR ")", MAC2STR(hapd->own_addr));
 			return -1;

src/drivers/driver.h

@@ -1497,11 +1497,13 @@ struct wpa_driver_ops {
 	 * @addr: Local address to use for the interface or %NULL to use the
 	 *	parent interface address
 	 * @bss_ctx: BSS context for %WPA_IF_AP_BSS interfaces
+	 * @drv_priv: Pointer for overwriting the driver context or %NULL if
+	 *	not allowed (applies only to %WPA_IF_AP_BSS type)
 	 * Returns: 0 on success, -1 on failure
 	 */
 	int (*if_add)(const char *iface, void *priv,
 		      enum wpa_driver_if_type type, const char *ifname,
-		      const u8 *addr, void *bss_ctx);
+		      const u8 *addr, void *bss_ctx, void **drv_priv);
 
 	/**
 	 * if_remove - Remove a virtual interface

src/drivers/driver_test.c

@@ -1030,7 +1030,7 @@ static int test_driver_bss_remove(void *priv, const char *ifname)
 
 static int test_driver_if_add(const char *iface, void *priv,
 			      enum wpa_driver_if_type type, const char *ifname,
-			      const u8 *addr, void *bss_ctx)
+			      const u8 *addr, void *bss_ctx, void **drv_priv)
 {
 	wpa_printf(MSG_DEBUG, "%s(iface=%s type=%d ifname=%s bss_ctx=%p)",
 		   __func__, iface, type, ifname, bss_ctx);