Add alloc_interface_addr() drv op option for specifying ifname

Some drivers may need to use a specific ifname for the virtual
interface, so allow them to do this with a new parameter passed
to the alloc_interface_addr() handler.

src/drivers/driver.h

@@ -1624,6 +1624,7 @@ struct wpa_driver_ops {
 	 * alloc_interface_addr - Allocate a virtual interface address
 	 * @priv: Private driver interface data
 	 * @addr: Buffer for returning the address
+	 * @ifname: Buffer for returning interface name (if needed)
 	 * Returns: 0 on success, -1 on failure
 	 *
 	 * This command pre-allocates an interface address for a new virtual
@@ -1631,12 +1632,15 @@ struct wpa_driver_ops {
 	 * the interface mode (e.g., AP vs. station) is not yet known, but the
 	 * address of the virtual interface is already needed. This helps with
 	 * drivers that cannot change interface mode without destroying and
-	 * re-creating the interface.
+	 * re-creating the interface. If the driver requires a specific
+	 * interface name to be used, the ifname buffer (up to IFNAMSIZ
+	 * characters) will be used to indicate which name must be used for
+	 * this virtual interface.
 	 *
-	 * The allocated address can be used in a bss_add() call to request a
+	 * The allocated address can be used in a if_add() call to request a
 	 * specific bssid.
 	 */
-	int (*alloc_interface_addr)(void *priv, u8 *addr);
+	int (*alloc_interface_addr)(void *priv, u8 *addr, char *ifname);
 
 	/**
 	 * release_interface_addr - Release a virtual interface address
@@ -1645,7 +1649,7 @@ struct wpa_driver_ops {
 	 *
 	 * This command is used to release a virtual interface address that was
 	 * allocated with alloc_interface_addr(), but has not yet been used
-	 * with bss_add() to actually create the interface. This allows the
+	 * with if_add() to actually create the interface. This allows the
 	 * driver to release the pending allocation for a new interface.
 	 */
 	void (*release_interface_addr)(void *priv, const u8 *addr);

src/drivers/driver_nl80211.c

@@ -4705,10 +4705,14 @@ static int wpa_driver_nl80211_probe_req_report(void *priv, int report)
 }
 
 
-static int wpa_driver_nl80211_alloc_interface_addr(void *priv, u8 *addr)
+static int wpa_driver_nl80211_alloc_interface_addr(void *priv, u8 *addr,
+						   char *ifname)
 {
 	struct wpa_driver_nl80211_data *drv = priv;
 
+	if (ifname)
+		ifname[0] = '\0';
+
 	if (linux_get_ifhwaddr(drv->ioctl_sock, drv->ifname, addr) < 0)
 		return -1;
 

src/drivers/driver_test.c

@@ -2632,9 +2632,14 @@ static int wpa_driver_test_send_action(void *priv, unsigned int freq,
 }
 
 
-static int wpa_driver_test_alloc_interface_addr(void *priv, u8 *addr)
+static int wpa_driver_test_alloc_interface_addr(void *priv, u8 *addr,
+						char *ifname)
 {
 	struct wpa_driver_test_data *drv = priv;
+
+	if (ifname)
+		ifname[0] = '\0';
+
 	drv->alloc_iface_idx++;
 	addr[0] = 0x02; /* locally administered */
 	sha1_prf(drv->own_addr, ETH_ALEN, "hostapd test addr generation",

wpa_supplicant/driver_i.h

@@ -397,11 +397,11 @@ static inline int wpa_drv_send_action(struct wpa_supplicant *wpa_s,
 }
 
 static inline int wpa_drv_alloc_interface_addr(struct wpa_supplicant *wpa_s,
-					       u8 *addr)
+					       u8 *addr, char *ifname)
 {
 	if (wpa_s->driver->alloc_interface_addr)
 		return wpa_s->driver->alloc_interface_addr(wpa_s->drv_priv,
-							   addr);
+							   addr, ifname);
 	return -1;
 }