From b6d7a8bc9822667cb851bec465c3ad7cd6714e90 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Fri, 4 Nov 2011 01:47:13 +0100
Subject: [PATCH] add a hotplug op for preparing an interface bridge so that
 it's ready when an external process adds interfaces

---
 bridge.c | 21 ++++++++++++++++++---
 device.h |  1 +
 ubus.c   | 22 ++++++++++++++++++++++
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/bridge.c b/bridge.c
index 5ff7081..5337e3a 100644
--- a/bridge.c
+++ b/bridge.c
@@ -65,6 +65,7 @@ struct bridge_state {
 	struct bridge_config config;
 	struct blob_attr *ifnames;
 	bool active;
+	bool force_active;
 
 	struct list_head members;
 	int n_present;
@@ -131,6 +132,7 @@ bridge_remove_member(struct bridge_member *bm)
 	if (bst->dev.active)
 		bridge_disable_member(bm);
 
+	bst->force_active = false;
 	if (bst->n_present == 0)
 		device_set_present(&bst->dev, false);
 }
@@ -190,7 +192,7 @@ bridge_set_up(struct bridge_state *bst)
 	struct bridge_member *bm;
 	int ret;
 
-	if (!bst->n_present)
+	if (!bst->force_active && !bst->n_present)
 		return -ENOENT;
 
 	ret = system_bridge_addbr(&bst->dev, &bst->config);
@@ -200,7 +202,7 @@ bridge_set_up(struct bridge_state *bst)
 	list_for_each_entry(bm, &bst->members, list)
 		bridge_enable_member(bm);
 
-	if (!bst->n_present) {
+	if (!bst->force_active && !bst->n_present) {
 		/* initialization of all member interfaces failed */
 		system_bridge_delbr(&bst->dev);
 		device_set_present(&bst->dev, false);
@@ -289,10 +291,23 @@ bridge_hotplug_del(struct device *dev, struct device *member)
 		return 0;
 	}
 
-	return -ENOENT;
+	return UBUS_STATUS_NOT_FOUND;
+}
+
+static int
+bridge_hotplug_prepare(struct device *dev)
+{
+	struct bridge_state *bst;
+
+	bst = container_of(dev, struct bridge_state, dev);
+	bst->force_active = true;
+	device_set_present(&bst->dev, true);
+
+	return 0;
 }
 
 static const struct device_hotplug_ops bridge_ops = {
+	.prepare = bridge_hotplug_prepare,
 	.add = bridge_hotplug_add,
 	.del = bridge_hotplug_del
 };
diff --git a/device.h b/device.h
index a3728f3..0d9e6f4 100644
--- a/device.h
+++ b/device.h
@@ -111,6 +111,7 @@ struct device {
 };
 
 struct device_hotplug_ops {
+	int (*prepare)(struct device *dev);
 	int (*add)(struct device *main, struct device *member);
 	int (*del)(struct device *main, struct device *member);
 };
diff --git a/ubus.c b/ubus.c
index ce82a52..af5ba68 100644
--- a/ubus.c
+++ b/ubus.c
@@ -380,10 +380,32 @@ netifd_iface_remove(struct ubus_context *ctx, struct ubus_object *obj,
 	return 0;
 }
 
+static int
+netifd_handle_iface_prepare(struct ubus_context *ctx, struct ubus_object *obj,
+			    struct ubus_request_data *req, const char *method,
+			    struct blob_attr *msg)
+{
+	struct interface *iface;
+	struct device *dev;
+	const struct device_hotplug_ops *ops;
+
+	iface = container_of(obj, struct interface, ubus);
+	dev = iface->main_dev.dev;
+	if (!dev)
+		return 0;
+
+	ops = dev->hotplug_ops;
+	if (!ops)
+		return 0;
+
+	return ops->prepare(dev);
+}
+
 static struct ubus_method iface_object_methods[] = {
 	{ .name = "up", .handler = netifd_handle_up },
 	{ .name = "down", .handler = netifd_handle_down },
 	{ .name = "status", .handler = netifd_handle_status },
+	{ .name = "prepare", .handler = netifd_handle_iface_prepare },
 	UBUS_METHOD("add_device", netifd_iface_handle_device, dev_policy ),
 	UBUS_METHOD("remove_device", netifd_iface_handle_device, dev_policy ),
 	{ .name = "notify_proto", .handler = netifd_iface_notify_proto },
-- 
2.25.1