net: config: Wait network interface to come up

Before we try to set IP addresses to the network interface,
make sure that the interface is up.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>

subsys/net/lib/config/init.c

@@ -34,6 +34,10 @@ extern int net_init_clock_via_sntp(void);
 static K_SEM_DEFINE(waiter, 0, 1);
 static struct k_sem counter;
 
+#if defined(CONFIG_NET_NATIVE)
+static struct net_mgmt_event_callback mgmt_iface_cb;
+#endif
+
 #if defined(CONFIG_NET_DHCPV4) && defined(CONFIG_NET_NATIVE_IPV4)
 static struct net_mgmt_event_callback mgmt4_cb;
 
@@ -282,12 +286,50 @@ static void setup_ipv6(struct net_if *iface, u32_t flags)
 #define setup_ipv6(...)
 #endif /* CONFIG_NET_IPV6 */
 
+#if defined(CONFIG_NET_NATIVE)
+static void iface_up_handler(struct net_mgmt_event_callback *cb,
+			     u32_t mgmt_event, struct net_if *iface)
+{
+	if (mgmt_event == NET_EVENT_IF_UP) {
+		NET_INFO("Interface %p coming up", iface);
+
+		k_sem_reset(&counter);
+		k_sem_give(&waiter);
+	}
+}
+
+static bool check_interface(struct net_if *iface)
+{
+	if (net_if_is_up(iface)) {
+		k_sem_reset(&counter);
+		k_sem_give(&waiter);
+		return true;
+	}
+
+	NET_INFO("Waiting interface %p to be up...", iface);
+
+	net_mgmt_init_event_callback(&mgmt_iface_cb, iface_up_handler,
+				     NET_EVENT_IF_UP);
+	net_mgmt_add_event_callback(&mgmt_iface_cb);
+
+	return false;
+}
+#else
+static void check_interface(struct net_if *iface)
+{
+	k_sem_reset(&counter);
+	k_sem_give(&waiter);
+
+	return true;
+}
+#endif
+
 int net_config_init(const char *app_info, u32_t flags, s32_t timeout)
 {
 #define LOOP_DIVIDER 10
 	struct net_if *iface = net_if_get_default();
 	int loop = timeout / LOOP_DIVIDER;
-	int count = 0;
+	int count, need = 0;
 
 	if (app_info) {
 		NET_INFO("%s", log_strdup(app_info));
@@ -298,30 +340,56 @@ int net_config_init(const char *app_info, u32_t flags, s32_t timeout)
 		return -ENODEV;
 	}
 
-	if (flags & NET_CONFIG_NEED_IPV6) {
-		count++;
+	if (timeout < 0) {
+		count = -1;
+	} else if (timeout == 0) {
+		count = 0;
+	} else {
+		count = timeout / 1000 + 1;
 	}
 
-	if (flags & NET_CONFIG_NEED_IPV4) {
-		count++;
-	}
+	/* First make sure that network interface is up */
+	if (check_interface(iface) == false) {
+		k_sem_init(&counter, 1, UINT_MAX);
 
-	k_sem_init(&counter, count, UINT_MAX);
+		while (count--) {
+			if (!k_sem_count_get(&counter)) {
+				break;
+			}
 
-	setup_ipv4(iface);
+			if (k_sem_take(&waiter, loop)) {
+				if (!k_sem_count_get(&counter)) {
+					break;
+				}
+			}
+		}
 
-	setup_dhcpv4(iface);
+		/* If the above while() loop timeouted, reset the count so that
+		 * the while() loop below will not wait more.
+		 */
+		if (timeout > 0 && count < 0) {
+			count = 0;
+		}
+
+#if defined(CONFIG_NET_NATIVE)
+		net_mgmt_del_event_callback(&mgmt_iface_cb);
+#endif
+	}
 
+	setup_ipv4(iface);
+	setup_dhcpv4(iface);
 	setup_ipv6(iface, flags);
 
-	if (timeout < 0) {
-		count = -1;
-	} else if (timeout == 0) {
-		count = 0;
-	} else {
-		count = timeout / 1000 + 1;
+	if (flags & NET_CONFIG_NEED_IPV6) {
+		need++;
+	}
+
+	if (flags & NET_CONFIG_NEED_IPV4) {
+		need++;
 	}
 
+	k_sem_init(&counter, need, UINT_MAX);
+
 	/* Loop here until we are ready to continue. As we might need
 	 * to wait multiple events, sleep smaller amounts of data.
 	 */