// SPDX-License-Identifier: GPL-2.0
/* Copyright 2011-2014 Autronica Fire and Security AS
 *
 * Author(s):
 *      2011-2014 Arvid Brodin, arvid.brodin@alten.se
 *
 * Event handling for HSR and PRP devices.
 */

#include <linux/netdevice.h>
#include <net/rtnetlink.h>
#include <linux/rculist.h>
#include <linux/timer.h>
#include <linux/etherdevice.h>
#include "hsr_main.h"
#include "hsr_device.h"
#include "hsr_netlink.h"
#include "hsr_framereg.h"
#include "hsr_slave.h"

static bool hsr_slave_empty(struct hsr_priv *hsr)
{
        struct hsr_port *port;

        hsr_for_each_port_rtnl(hsr, port)
                if (port->type != HSR_PT_MASTER)
                        return false;
        return true;
}

static int hsr_netdev_notify(struct notifier_block *nb, unsigned long event,
                             void *ptr)
{
        struct hsr_port *port, *master;
        struct net_device *dev;
        struct hsr_priv *hsr;
        LIST_HEAD(list_kill);
        int mtu_max;
        int res;

        dev = netdev_notifier_info_to_dev(ptr);
        port = hsr_port_get_rtnl(dev);
        if (!port) {
                if (!is_hsr_master(dev))
                        return NOTIFY_DONE;     /* Not an HSR device */
                hsr = netdev_priv(dev);
                port = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
                if (!port) {
                        /* Resend of notification concerning removed device? */
                        return NOTIFY_DONE;
                }
        } else {
                hsr = port->hsr;
        }

        switch (event) {
        case NETDEV_UP:         /* Administrative state DOWN */
        case NETDEV_DOWN:       /* Administrative state UP */
        case NETDEV_CHANGE:     /* Link (carrier) state changes */
                hsr_check_carrier_and_operstate(hsr);
                break;
        case NETDEV_CHANGENAME:
                if (is_hsr_master(dev))
                        hsr_debugfs_rename(dev);
                break;
        case NETDEV_CHANGEADDR:
                if (port->type == HSR_PT_MASTER) {
                        /* This should not happen since there's no
                         * ndo_set_mac_address() for HSR devices - i.e. not
                         * supported.
                         */
                        break;
                }

                master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);

                if (port->type == HSR_PT_SLAVE_A) {
                        eth_hw_addr_set(master->dev, dev->dev_addr);
                        call_netdevice_notifiers(NETDEV_CHANGEADDR,
                                                 master->dev);

                        if (hsr->prot_version == PRP_V1) {
                                port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
                                if (port) {
                                        eth_hw_addr_set(port->dev, dev->dev_addr);
                                        call_netdevice_notifiers(NETDEV_CHANGEADDR,
                                                                 port->dev);
                                }
                        }
                }

                /* Make sure we recognize frames from ourselves in hsr_rcv() */
                port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
                res = hsr_create_self_node(hsr,
                                           master->dev->dev_addr,
                                           port ?
                                                port->dev->dev_addr :
                                                master->dev->dev_addr);
                if (res)
                        netdev_warn(master->dev,
                                    "Could not update HSR node address.\n");
                break;
        case NETDEV_CHANGEMTU:
                if (port->type == HSR_PT_MASTER)
                        break; /* Handled in ndo_change_mtu() */
                mtu_max = hsr_get_max_mtu(port->hsr);
                master = hsr_port_get_hsr(port->hsr, HSR_PT_MASTER);
                WRITE_ONCE(master->dev->mtu, mtu_max);
                break;
        case NETDEV_UNREGISTER:
                if (!is_hsr_master(dev)) {
                        master = hsr_port_get_hsr(port->hsr, HSR_PT_MASTER);
                        hsr_del_port(port);
                        if (hsr_slave_empty(master->hsr)) {
                                const struct rtnl_link_ops *ops;

                                ops = master->dev->rtnl_link_ops;
                                ops->dellink(master->dev, &list_kill);
                                unregister_netdevice_many(&list_kill);
                        }
                }
                break;
        case NETDEV_PRE_TYPE_CHANGE:
                /* HSR works only on Ethernet devices. Refuse slave to change
                 * its type.
                 */
                return NOTIFY_BAD;
        }

        return NOTIFY_DONE;
}

struct hsr_port *hsr_port_get_hsr(struct hsr_priv *hsr, enum hsr_port_type pt)
{
        struct hsr_port *port;

        hsr_for_each_port_rtnl(hsr, port)
                if (port->type == pt)
                        return port;
        return NULL;
}

int hsr_get_version(struct net_device *dev, enum hsr_version *ver)
{
        struct hsr_priv *hsr;

        hsr = netdev_priv(dev);
        *ver = hsr->prot_version;

        return 0;
}
EXPORT_SYMBOL(hsr_get_version);

static struct notifier_block hsr_nb = {
        .notifier_call = hsr_netdev_notify,     /* Slave event notifications */
};

static int __init hsr_init(void)
{
        int err;

        BUILD_BUG_ON(sizeof(struct hsr_tag) != HSR_HLEN);

        err = register_netdevice_notifier(&hsr_nb);
        if (err)
                return err;

        err = hsr_netlink_init();
        if (err) {
                unregister_netdevice_notifier(&hsr_nb);
                return err;
        }

        return 0;
}

static void __exit hsr_exit(void)
{
        hsr_netlink_exit();
        hsr_debugfs_remove_root();
        unregister_netdevice_notifier(&hsr_nb);
}

module_init(hsr_init);
module_exit(hsr_exit);
MODULE_DESCRIPTION("High-availability Seamless Redundancy (HSR) driver");
MODULE_LICENSE("GPL");