nl80211: Add preliminary code for testing separate P2P group interface

driver_param=use_p2p_group_interface=1 can now be used to test
nl80211-drivers with separate P2P group interface. In other words,
the main interface (e.g., wlan0) is reserved for P2P management
operations and non-P2P connections and a new group interface (e.g.,
p2p-wlan0-0) is created for the P2P group.

This implementation is very minimal, i.e., it only support address
allocation for a single P2P group interface (if the driver does not
handle this internally). In addition, not all functionality has yet
been tested, so for now, this is disabled by default and needs that
special driver_param to enable.

src/drivers/driver_nl80211.c

@@ -5449,8 +5449,44 @@ static int wpa_driver_nl80211_if_add(void *priv, enum wpa_driver_if_type type,
 	}
 
 	if (!addr &&
-	    linux_get_ifhwaddr(drv->ioctl_sock, bss->ifname, if_addr) < 0)
+	    linux_get_ifhwaddr(drv->ioctl_sock, bss->ifname, if_addr) < 0) {
+		nl80211_remove_iface(drv, ifidx);
 		return -1;
+	}
+
+#ifdef CONFIG_P2P
+	if (!addr &&
+	    (type == WPA_IF_P2P_CLIENT || type == WPA_IF_P2P_GROUP ||
+	     type == WPA_IF_P2P_GO)) {
+		/* Enforce unique P2P Interface Address */
+		u8 new_addr[ETH_ALEN], own_addr[ETH_ALEN];
+
+		if (linux_get_ifhwaddr(drv->ioctl_sock, bss->ifname, own_addr)
+		    < 0 ||
+		    linux_get_ifhwaddr(drv->ioctl_sock, ifname, new_addr) < 0)
+		{
+			nl80211_remove_iface(drv, ifidx);
+			return -1;
+		}
+		if (os_memcmp(own_addr, new_addr, ETH_ALEN) == 0) {
+			wpa_printf(MSG_DEBUG, "nl80211: Allocate new address "
+				   "for P2P group interface");
+			/* TODO: more complete implementation to handle
+			 * multiple groups etc.. */
+			if (own_addr[0] & 0x02) {
+				nl80211_remove_iface(drv, ifidx);
+				return -1;
+			}
+			new_addr[0] |= 0x02;
+			if (linux_set_ifhwaddr(drv->ioctl_sock, ifname,
+					       new_addr) < 0) {
+				nl80211_remove_iface(drv, ifidx);
+				return -1;
+			}
+			os_memcpy(if_addr, new_addr, ETH_ALEN);
+		}
+	}
+#endif /* CONFIG_P2P */
 
 #ifdef HOSTAPD
 	if (type == WPA_IF_AP_BSS) {
@@ -5951,6 +5987,28 @@ static int nl80211_set_intra_bss(void *priv, int enabled)
 }
 
 
+static int nl80211_set_param(void *priv, const char *param)
+{
+	struct i802_bss *bss = priv;
+	struct wpa_driver_nl80211_data *drv = bss->drv;
+
+	wpa_printf(MSG_DEBUG, "nl80211: driver param='%s'", param);
+	if (param == NULL)
+		return 0;
+
+#ifdef CONFIG_P2P
+	if (os_strstr(param, "use_p2p_group_interface=1")) {
+		wpa_printf(MSG_DEBUG, "nl80211: Use separate P2P group "
+			   "interface");
+		drv->capa.flags |= WPA_DRIVER_FLAGS_P2P_CONCURRENT;
+		drv->capa.flags |= WPA_DRIVER_FLAGS_P2P_MGMT_AND_NON_P2P;
+	}
+#endif /* CONFIG_P2P */
+
+	return 0;
+}
+
+
 const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 	.name = "nl80211",
 	.desc = "Linux nl80211/cfg80211",
@@ -6011,4 +6069,5 @@ const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 	.signal_monitor = nl80211_signal_monitor,
 	.send_frame = nl80211_send_frame,
 	.set_intra_bss = nl80211_set_intra_bss,
+	.set_param = nl80211_set_param,
 };