/*
   *	Device event handling
   *	Linux ethernet bridge
   *
   *	Authors:
   *	Lennert Buytenhek		<buytenh@gnu.org>
   *

   *	This program is free software; you can redistribute it and/or
   *	modify it under the terms of the GNU General Public License
   *	as published by the Free Software Foundation; either version
   *	2 of the License, or (at your option) any later version.
   */
  
  #include <linux/kernel.h>

  #include <linux/rtnetlink.h>

  #include <net/net_namespace.h>

  
  #include "br_private.h"
  
  static int br_device_event(struct notifier_block *unused, unsigned long event, void *ptr);
  
  struct notifier_block br_device_notifier = {
  	.notifier_call = br_device_event
  };
  
  /*
   * Handle changes in state of network devices enslaved to a bridge.

   *

   * Note: don't care about up/down if bridge itself is down, because
   *     port state is checked when bridge is brought up.
   */
  static int br_device_event(struct notifier_block *unused, unsigned long event, void *ptr)
  {
  	struct net_device *dev = ptr;

  	struct net_bridge_port *p;

  	struct net_bridge *br;

  	bool changed_addr;

  	int err;

  	/* register of bridge completed, add sysfs entries */

  	if ((dev->priv_flags & IFF_EBRIDGE) && event == NETDEV_REGISTER) {

  		br_sysfs_addbr(dev);
  		return NOTIFY_DONE;
  	}

  	/* not a port of a bridge */

  	p = br_port_get_rtnl(dev);
  	if (!p)

  		return NOTIFY_DONE;
  
  	br = p->br;

  	switch (event) {
  	case NETDEV_CHANGEMTU:
  		dev_set_mtu(br->dev, br_min_mtu(br));
  		break;
  
  	case NETDEV_CHANGEADDR:

  		spin_lock_bh(&br->lock);

  		br_fdb_changeaddr(p, dev->dev_addr);

  		changed_addr = br_stp_recalculate_bridge_id(br);

  		spin_unlock_bh(&br->lock);

  
  		if (changed_addr)
  			call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);

  		break;

  	case NETDEV_CHANGE:

  		br_port_carrier_check(p);

  		break;

  	case NETDEV_FEAT_CHANGE:

  		netdev_update_features(br->dev);

  		break;

  	case NETDEV_DOWN:

  		spin_lock_bh(&br->lock);

  		if (br->dev->flags & IFF_UP)
  			br_stp_disable_port(p);

  		spin_unlock_bh(&br->lock);

  		break;
  
  	case NETDEV_UP:

  		if (netif_carrier_ok(dev) && (br->dev->flags & IFF_UP)) {
  			spin_lock_bh(&br->lock);

  			br_stp_enable_port(p);

  			spin_unlock_bh(&br->lock);
  		}

  		break;
  
  	case NETDEV_UNREGISTER:

  		br_del_if(br, dev);

  		break;

  	case NETDEV_CHANGENAME:
  		err = br_sysfs_renameif(p);
  		if (err)
  			return notifier_from_errno(err);
  		break;

  	case NETDEV_PRE_TYPE_CHANGE:
  		/* Forbid underlaying device to change its type. */
  		return NOTIFY_BAD;

  	}

  	/* Events that may cause spanning tree to refresh */
  	if (event == NETDEV_CHANGEADDR || event == NETDEV_UP ||
  	    event == NETDEV_CHANGE || event == NETDEV_DOWN)
  		br_ifinfo_notify(RTM_NEWLINK, p);

  	return NOTIFY_DONE;
  }