3 files changed, 97 insertions, 5 deletions

diff --git a/interface.c b/interface.c
index d45f2d5..52d30fc 100644
--- a/interface.c
+++ b/interface.c
@@ -7,7 +7,53 @@
 
 LIST_HEAD(interfaces);
 
-static int interface_event(struct interface *iface, enum interface_event ev)
+static void
+clear_interface_errors(struct interface *iface)
+{
+	struct interface_error *error, *tmp;
+
+	list_for_each_entry_safe(error, tmp, &iface->errors, list) {
+		list_del(&error->list);
+		free(error);
+	}
+}
+
+void interface_add_error(struct interface *iface, const char *subsystem,
+			 const char *code, const char **data, int n_data)
+{
+	struct interface_error *error;
+	int i, len = 0;
+	int *datalen;
+	char *dest;
+
+	if (n_data) {
+		len = n_data * sizeof(char *);
+		datalen = alloca(len);
+		for (i = 0; i < n_data; i++) {
+			datalen[i] = strlen(data[i]) + 1;
+			len += datalen[i];
+		}
+	}
+
+	error = calloc(1, sizeof(*error) + sizeof(char *) + len);
+	if (!error)
+		return;
+
+	list_add_tail(&error->list, &iface->errors);
+	error->subsystem = subsystem;
+	error->code = code;
+
+	dest = (char *) &error->data[n_data + 1];
+	for (i = 0; i < n_data; i++) {
+		error->data[i] = dest;
+		memcpy(dest, data[i], datalen[i]);
+		dest += datalen[i];
+	}
+	error->data[n_data] = NULL;
+}
+
+static int
+interface_event(struct interface *iface, enum interface_event ev)
 {
 	if (!iface->state || !iface->state->event)
 		return 0;
@@ -35,6 +81,8 @@ __set_interface_up(struct interface *iface)
 static void
 __set_interface_down(struct interface *iface)
 {
+	clear_interface_errors(iface);
+
 	if (!iface->up)
 		return;
 
@@ -87,6 +135,8 @@ alloc_interface(const char *name)
 	iface->l3_iface = &iface->main_dev;
 	strncpy(iface->name, name, sizeof(iface->name) - 1);
 	list_add(&iface->list, &interfaces);
+	INIT_LIST_HEAD(&iface->errors);
+
 	netifd_ubus_add_interface(iface);
 
 	return iface;
@@ -148,6 +198,11 @@ set_interface_up(struct interface *iface)
 {
 	iface->autostart = true;
 
+	if (!iface->active) {
+		interface_add_error(iface, "interface", "NO_DEVICE", NULL, 0);
+		return -1;
+	}
+
 	if (iface->up || !iface->active)
 		return -1;
 
@@ -159,10 +214,6 @@ int
 set_interface_down(struct interface *iface)
 {
 	iface->autostart = false;
-
-	if (!iface->up)
-		return -1;
-
 	__set_interface_down(iface);
 
 	return 0;
diff --git a/interface.h b/interface.h
index 0fd70d7..b3a86f2 100644
--- a/interface.h
+++ b/interface.h
@@ -19,6 +19,14 @@ struct interface_proto_state {
 	void (*free)(struct interface *, struct interface_proto_state *);
 };
 
+struct interface_error {
+	struct list_head list;
+
+	const char *subsystem;
+	const char *code;
+	const char *data[];
+};
+
 /*
  * interface configuration
  */
@@ -45,6 +53,9 @@ struct interface {
 	/* primary protocol state */
 	struct interface_proto_state *state;
 
+	/* errors/warnings while trying to bring up the interface */
+	struct list_head errors;
+
 	struct ubus_object ubus;
 };
 
@@ -58,6 +69,9 @@ int set_interface_down(struct interface *iface);
 int interface_add_link(struct interface *iface, struct device *llif);
 void interface_remove_link(struct interface *iface, struct device *llif);
 
+void interface_add_error(struct interface *iface, const char *subsystem,
+			 const char *code, const char **data, int n_data);
+
 int interface_attach_bridge(struct interface *iface, struct uci_section *s);
 
 #endif
diff --git a/ubus.c b/ubus.c
index cdd1ff0..159d5f5 100644
--- a/ubus.c
+++ b/ubus.c
@@ -110,6 +110,30 @@ static int netifd_handle_down(struct ubus_context *ctx, struct ubus_object *obj,
 	return 0;
 }
 
+static void netifd_add_interface_errors(struct blob_buf *b, struct interface *iface)
+{
+	struct interface_error *error;
+	void *e, *e2, *e3;
+	int i;
+
+	e = blobmsg_open_array(b, "errors");
+	list_for_each_entry(error, &iface->errors, list) {
+		e2 = blobmsg_open_table(b, NULL);
+
+		blobmsg_add_string(b, "subsystem", error->subsystem);
+		blobmsg_add_string(b, "code", error->code);
+		if (error->data[0]) {
+			e3 = blobmsg_open_array(b, "data");
+			for (i = 0; error->data[i]; i++)
+				blobmsg_add_string(b, NULL, error->data[i]);
+			blobmsg_close_array(b, e3);
+		}
+
+		blobmsg_close_table(b, e2);
+	}
+	blobmsg_close_array(b, e);
+}
+
 static int netifd_handle_status(struct ubus_context *ctx, struct ubus_object *obj,
 				struct ubus_request_data *req, const char *method,
 				struct blob_attr *msg)
@@ -142,6 +166,9 @@ static int netifd_handle_status(struct ubus_context *ctx, struct ubus_object *ob
 		blobmsg_close_table(&b, devinfo);
 	}
 
+	if (!list_is_empty(&iface->errors))
+		netifd_add_interface_errors(&b, iface);
+
 	ubus_send_reply(ctx, req, b.head);
 
 	return 0;