br_notify.c

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/*
 *  Device event handling
 *  Linux ethernet bridge
 *
 *  Authors:
 *  Lennert Buytenhek       <[email protected]>
 *
 *  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;
}