P2P: Adding option to manage device drivers creating random MAC addresses

Add option 2 to the p2p_device_random_mac_addr configuration option to
support device drivers which use by default random MAC adresses when
creating a new P2P Device interface (for instance, the BCM2711 80211
wireless device driver included in Raspberry Pi 4 Model B). In such
case, this option allows to create the P2P Device interface correctly
when using P2P permanent groups, enabling wpa_supplicant to reuse the
same MAC address when re-invoking a P2P permanent group.

update_config=1 is required.

Signed-off-by: Ircama <amacri@tiscali.it>

src/drivers/driver_nl80211.c

@@ -5261,6 +5261,10 @@ static int nl80211_create_iface_once(struct wpa_driver_nl80211_data *drv,
 	if (nla_put_flag(msg, NL80211_ATTR_IFACE_SOCKET_OWNER))
 		goto fail;
 
+	if ((addr && iftype == NL80211_IFTYPE_P2P_DEVICE) &&
+	    nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, addr))
+		goto fail;
+
 	ret = send_and_recv_msgs(drv, msg, handler, arg, NULL, NULL);
 	msg = NULL;
 	if (ret) {

wpa_supplicant/config.h

@@ -1554,9 +1554,31 @@ struct wpa_config {
 	/**
 	 * p2p_device_random_mac_addr - P2P Device MAC address policy default
 	 *
-	 * 0 = use permanent MAC address
+	 * 0 = use permanent MAC address (the one set by default by the device
+	 *     driver). Notice that, if the device driver is configured to
+	 *     always use random MAC addresses, this flag breaks reinvoking a
+	 *     persistent group, so flags 1 or 2 should be used instead with
+	 *     such drivers if persistent groups are used.
 	 * 1 = use random MAC address on creating the interface if there is no
-	 * persistent groups.
+	 *     persistent group. Besides, if a persistent group is created,
+	 *     p2p_device_persistent_mac_addr is set to the MAC address of the
+	 *     P2P Device interface, so that this address will be subsequently
+	 *     used to change the MAC address of the P2P Device interface. With
+	 *     no persistent group, the random MAC address is created by
+	 *     wpa_supplicant, changing the one set by the device driver.
+	 *     The device driver shall support SIOCGIFFLAGS/SIOCSIFFLAGS ioctl
+	 *     interface control operations.
+	 * 2 = this flag should be used when the device driver uses random MAC
+	 *     addresses by default when a P2P Device interface is created.
+	 *     If p2p_device_persistent_mac_addr is set, use this MAC address
+	 *     on creating the P2P Device interface. If not set, use the
+	 *     default method adopted by the device driver (e.g., random MAC
+	 *     address). Besides, if a persistent group is created,
+	 *     p2p_device_persistent_mac_addr is set to the MAC address of the
+	 *     P2P Device interface, so that this address will be subsequently
+	 *     used in place of the default address set by the device driver.
+	 *     (This option does not need support of SIOCGIFFLAGS/SIOCSIFFLAGS
+	 *     ioctl interface control operations and uses NL80211_ATTR_MAC).
 	 *
 	 * By default, permanent MAC address is used.
 	 */

wpa_supplicant/p2p_supplicant.c

@@ -3980,6 +3980,7 @@ int wpas_p2p_add_p2pdev_interface(struct wpa_supplicant *wpa_s,
 	char ifname[100];
 	char force_name[100];
 	int ret;
+	const u8 *if_addr = NULL;
 
 	ret = os_snprintf(ifname, sizeof(ifname), P2P_MGMT_DEVICE_PREFIX "%s",
 			  wpa_s->ifname);
@@ -3991,7 +3992,12 @@ int wpas_p2p_add_p2pdev_interface(struct wpa_supplicant *wpa_s,
 	ifname[IFNAMSIZ - 1] = '\0';
 	force_name[0] = '\0';
 	wpa_s->pending_interface_type = WPA_IF_P2P_DEVICE;
-	ret = wpa_drv_if_add(wpa_s, WPA_IF_P2P_DEVICE, ifname, NULL, NULL,
+
+	if (wpa_s->conf->p2p_device_random_mac_addr == 2 &&
+	    !is_zero_ether_addr(wpa_s->conf->p2p_device_persistent_mac_addr))
+		if_addr = wpa_s->conf->p2p_device_persistent_mac_addr;
+
+	ret = wpa_drv_if_add(wpa_s, WPA_IF_P2P_DEVICE, ifname, if_addr, NULL,
 			     force_name, wpa_s->pending_interface_addr, NULL);
 	if (ret < 0) {
 		wpa_printf(MSG_DEBUG, "P2P: Failed to create P2P Device interface");
@@ -4568,6 +4574,16 @@ int wpas_p2p_mac_setup(struct wpa_supplicant *wpa_s)
 	if (wpa_s->conf->p2p_device_random_mac_addr == 0)
 		return 0;
 
+	if (wpa_s->conf->p2p_device_random_mac_addr == 2) {
+		if (is_zero_ether_addr(
+			    wpa_s->conf->p2p_device_persistent_mac_addr) &&
+		    !is_zero_ether_addr(wpa_s->own_addr)) {
+			os_memcpy(wpa_s->conf->p2p_device_persistent_mac_addr,
+				  wpa_s->own_addr, ETH_ALEN);
+		}
+		return 0;
+	}
+
 	if (!wpa_s->conf->ssid) {
 		if (random_mac_addr(addr) < 0) {
 			wpa_msg(wpa_s, MSG_INFO,