// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      Generic parts
 *      Linux ethernet bridge
 *
 *      Authors:
 *      Lennert Buytenhek               <buytenh@gnu.org>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/llc.h>
#include <net/llc.h>
#include <net/stp.h>
#include <net/switchdev.h>

#include "br_private.h"

/*
 * 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 netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
        struct netdev_notifier_pre_changeaddr_info *prechaddr_info;
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
        struct net_bridge_port *p;
        struct net_bridge *br;
        bool notified = false;
        bool changed_addr;
        int err;

        if (netif_is_bridge_master(dev)) {
                struct net_bridge *br = netdev_priv(dev);

                if (event == NETDEV_REGISTER)
                        br_fdb_change_mac_address(br, dev->dev_addr);

                err = br_vlan_bridge_event(dev, event, ptr);
                if (err)
                        return notifier_from_errno(err);

                if (event == NETDEV_REGISTER) {
                        /* register of bridge completed, add sysfs entries */
                        err = br_sysfs_addbr(dev);
                        if (err)
                                return notifier_from_errno(err);

                        return NOTIFY_DONE;
                }
        }

        if (is_vlan_dev(dev)) {
                struct net_device *real_dev = vlan_dev_real_dev(dev);

                if (netif_is_bridge_master(real_dev))
                        br_vlan_vlan_upper_event(real_dev, dev, event);
        }

        /* 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:
                br_mtu_auto_adjust(br);
                break;

        case NETDEV_PRE_CHANGEADDR:
                if (br->dev->addr_assign_type == NET_ADDR_SET)
                        break;
                prechaddr_info = ptr;
                err = netif_pre_changeaddr_notify(br->dev,
                                                  prechaddr_info->dev_addr,
                                                  extack);
                if (err)
                        return notifier_from_errno(err);
                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, &notified);
                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);
                        notified = true;
                }
                spin_unlock_bh(&br->lock);
                break;

        case NETDEV_UP:
                if (netif_running(br->dev) && netif_oper_up(dev)) {
                        spin_lock_bh(&br->lock);
                        br_stp_enable_port(p);
                        notified = true;
                        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 underlying device to change its type. */
                return NOTIFY_BAD;

        case NETDEV_RESEND_IGMP:
                /* Propagate to master device */
                call_netdevice_notifiers(event, br->dev);
                break;
        }

        if (event != NETDEV_UNREGISTER)
                br_vlan_port_event(p, event);

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

        return NOTIFY_DONE;
}

static struct notifier_block br_device_notifier = {
        .notifier_call = br_device_event
};

/* called with RTNL or RCU */
static int br_switchdev_event(struct notifier_block *unused,
                              unsigned long event, void *ptr)
{
        struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
        struct net_bridge_port *p;
        struct net_bridge *br;
        struct switchdev_notifier_fdb_info *fdb_info;
        int err = NOTIFY_DONE;

        p = br_port_get_rtnl_rcu(dev);
        if (!p)
                goto out;

        br = p->br;

        switch (event) {
        case SWITCHDEV_FDB_ADD_TO_BRIDGE:
                fdb_info = ptr;
                err = br_fdb_external_learn_add(br, p, fdb_info->addr,
                                                fdb_info->vid,
                                                fdb_info->locked, false);
                if (err) {
                        err = notifier_from_errno(err);
                        break;
                }
                br_fdb_offloaded_set(br, p, fdb_info->addr,
                                     fdb_info->vid, fdb_info->offloaded);
                break;
        case SWITCHDEV_FDB_DEL_TO_BRIDGE:
                fdb_info = ptr;
                err = br_fdb_external_learn_del(br, p, fdb_info->addr,
                                                fdb_info->vid, false);
                if (err)
                        err = notifier_from_errno(err);
                break;
        case SWITCHDEV_FDB_OFFLOADED:
                fdb_info = ptr;
                br_fdb_offloaded_set(br, p, fdb_info->addr,
                                     fdb_info->vid, fdb_info->offloaded);
                break;
        case SWITCHDEV_FDB_FLUSH_TO_BRIDGE:
                fdb_info = ptr;
                /* Don't delete static entries */
                br_fdb_delete_by_port(br, p, fdb_info->vid, 0);
                break;
        }

out:
        return err;
}

static struct notifier_block br_switchdev_notifier = {
        .notifier_call = br_switchdev_event,
};

/* called under rtnl_mutex */
static int br_switchdev_blocking_event(struct notifier_block *nb,
                                       unsigned long event, void *ptr)
{
        struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
        struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
        struct switchdev_notifier_brport_info *brport_info;
        const struct switchdev_brport *b;
        struct net_bridge_port *p;
        int err = NOTIFY_DONE;

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

        switch (event) {
        case SWITCHDEV_BRPORT_OFFLOADED:
                brport_info = ptr;
                b = &brport_info->brport;

                err = br_switchdev_port_offload(p, b->dev, b->ctx,
                                                b->atomic_nb, b->blocking_nb,
                                                b->tx_fwd_offload, extack);
                err = notifier_from_errno(err);
                break;
        case SWITCHDEV_BRPORT_UNOFFLOADED:
                brport_info = ptr;
                b = &brport_info->brport;

                br_switchdev_port_unoffload(p, b->ctx, b->atomic_nb,
                                            b->blocking_nb);
                break;
        case SWITCHDEV_BRPORT_REPLAY:
                brport_info = ptr;
                b = &brport_info->brport;

                err = br_switchdev_port_replay(p, b->dev, b->ctx, b->atomic_nb,
                                               b->blocking_nb, extack);
                err = notifier_from_errno(err);
                break;
        }

out:
        return err;
}

static struct notifier_block br_switchdev_blocking_notifier = {
        .notifier_call = br_switchdev_blocking_event,
};

static int
br_toggle_fdb_local_vlan_0(struct net_bridge *br, bool on,
                           struct netlink_ext_ack *extack)
{
        int err;

        if (br_opt_get(br, BROPT_FDB_LOCAL_VLAN_0) == on)
                return 0;

        err = br_fdb_toggle_local_vlan_0(br, on, extack);
        if (err)
                return err;

        br_opt_toggle(br, BROPT_FDB_LOCAL_VLAN_0, on);
        return 0;
}

/* br_boolopt_toggle - change user-controlled boolean option
 *
 * @br: bridge device
 * @opt: id of the option to change
 * @on: new option value
 * @extack: extack for error messages
 *
 * Changes the value of the respective boolean option to @on taking care of
 * any internal option value mapping and configuration.
 */
int br_boolopt_toggle(struct net_bridge *br, enum br_boolopt_id opt, bool on,
                      struct netlink_ext_ack *extack)
{
        int err = 0;

        switch (opt) {
        case BR_BOOLOPT_NO_LL_LEARN:
                br_opt_toggle(br, BROPT_NO_LL_LEARN, on);
                break;
        case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
                err = br_multicast_toggle_vlan_snooping(br, on, extack);
                break;
        case BR_BOOLOPT_MST_ENABLE:
                err = br_mst_set_enabled(br, on, extack);
                break;
        case BR_BOOLOPT_MDB_OFFLOAD_FAIL_NOTIFICATION:
                br_opt_toggle(br, BROPT_MDB_OFFLOAD_FAIL_NOTIFICATION, on);
                break;
        case BR_BOOLOPT_FDB_LOCAL_VLAN_0:
                err = br_toggle_fdb_local_vlan_0(br, on, extack);
                break;
        default:
                /* shouldn't be called with unsupported options */
                WARN_ON(1);
                break;
        }

        return err;
}

int br_boolopt_get(const struct net_bridge *br, enum br_boolopt_id opt)
{
        switch (opt) {
        case BR_BOOLOPT_NO_LL_LEARN:
                return br_opt_get(br, BROPT_NO_LL_LEARN);
        case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
                return br_opt_get(br, BROPT_MCAST_VLAN_SNOOPING_ENABLED);
        case BR_BOOLOPT_MST_ENABLE:
                return br_opt_get(br, BROPT_MST_ENABLED);
        case BR_BOOLOPT_MDB_OFFLOAD_FAIL_NOTIFICATION:
                return br_opt_get(br, BROPT_MDB_OFFLOAD_FAIL_NOTIFICATION);
        case BR_BOOLOPT_FDB_LOCAL_VLAN_0:
                return br_opt_get(br, BROPT_FDB_LOCAL_VLAN_0);
        default:
                /* shouldn't be called with unsupported options */
                WARN_ON(1);
                break;
        }

        return 0;
}

int br_boolopt_multi_toggle(struct net_bridge *br,
                            struct br_boolopt_multi *bm,
                            struct netlink_ext_ack *extack)
{
        unsigned long bitmap = bm->optmask;
        int err = 0;
        int opt_id;

        opt_id = find_next_bit(&bitmap, BITS_PER_LONG, BR_BOOLOPT_MAX);
        if (opt_id != BITS_PER_LONG) {
                NL_SET_ERR_MSG_FMT_MOD(extack, "Unknown boolean option %d",
                                       opt_id);
                return -EINVAL;
        }

        for_each_set_bit(opt_id, &bitmap, BR_BOOLOPT_MAX) {
                bool on = !!(bm->optval & BIT(opt_id));

                err = br_boolopt_toggle(br, opt_id, on, extack);
                if (err) {
                        br_debug(br, "boolopt multi-toggle error: option: %d current: %d new: %d error: %d\n",
                                 opt_id, br_boolopt_get(br, opt_id), on, err);
                        break;
                }
        }

        return err;
}

void br_boolopt_multi_get(const struct net_bridge *br,
                          struct br_boolopt_multi *bm)
{
        u32 optval = 0;
        int opt_id;

        for (opt_id = 0; opt_id < BR_BOOLOPT_MAX; opt_id++)
                optval |= (br_boolopt_get(br, opt_id) << opt_id);

        bm->optval = optval;
        bm->optmask = GENMASK((BR_BOOLOPT_MAX - 1), 0);
}

/* private bridge options, controlled by the kernel */
void br_opt_toggle(struct net_bridge *br, enum net_bridge_opts opt, bool on)
{
        bool cur = !!br_opt_get(br, opt);

        br_debug(br, "toggle option: %d state: %d -> %d\n",
                 opt, cur, on);

        if (cur == on)
                return;

        if (on)
                set_bit(opt, &br->options);
        else
                clear_bit(opt, &br->options);
}

static void __net_exit br_net_exit_rtnl(struct net *net,
                                        struct list_head *dev_to_kill)
{
        struct net_device *dev;

        ASSERT_RTNL_NET(net);

        for_each_netdev(net, dev)
                if (netif_is_bridge_master(dev))
                        br_dev_delete(dev, dev_to_kill);
}

static struct pernet_operations br_net_ops = {
        .exit_rtnl = br_net_exit_rtnl,
};

static const struct stp_proto br_stp_proto = {
        .rcv    = br_stp_rcv,
};

static int __init br_init(void)
{
        int err;

        BUILD_BUG_ON(sizeof(struct br_input_skb_cb) > sizeof_field(struct sk_buff, cb));

        err = stp_proto_register(&br_stp_proto);
        if (err < 0) {
                pr_err("bridge: can't register sap for STP\n");
                return err;
        }

        err = br_fdb_init();
        if (err)
                goto err_out;

        err = register_pernet_subsys(&br_net_ops);
        if (err)
                goto err_out1;

        err = br_nf_core_init();
        if (err)
                goto err_out2;

        err = register_netdevice_notifier(&br_device_notifier);
        if (err)
                goto err_out3;

        err = register_switchdev_notifier(&br_switchdev_notifier);
        if (err)
                goto err_out4;

        err = register_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
        if (err)
                goto err_out5;

        err = br_netlink_init();
        if (err)
                goto err_out6;

        brioctl_set(br_ioctl_stub);

#if IS_ENABLED(CONFIG_ATM_LANE)
        br_fdb_test_addr_hook = br_fdb_test_addr;
#endif

#if IS_MODULE(CONFIG_BRIDGE_NETFILTER)
        pr_info("bridge: filtering via arp/ip/ip6tables is no longer available "
                "by default. Update your scripts to load br_netfilter if you "
                "need this.\n");
#endif

        return 0;

err_out6:
        unregister_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
err_out5:
        unregister_switchdev_notifier(&br_switchdev_notifier);
err_out4:
        unregister_netdevice_notifier(&br_device_notifier);
err_out3:
        br_nf_core_fini();
err_out2:
        unregister_pernet_subsys(&br_net_ops);
err_out1:
        br_fdb_fini();
err_out:
        stp_proto_unregister(&br_stp_proto);
        return err;
}

static void __exit br_deinit(void)
{
        stp_proto_unregister(&br_stp_proto);
        br_netlink_fini();
        unregister_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
        unregister_switchdev_notifier(&br_switchdev_notifier);
        unregister_netdevice_notifier(&br_device_notifier);
        brioctl_set(NULL);
        unregister_pernet_subsys(&br_net_ops);

        rcu_barrier(); /* Wait for completion of call_rcu()'s */

        br_nf_core_fini();
#if IS_ENABLED(CONFIG_ATM_LANE)
        br_fdb_test_addr_hook = NULL;
#endif
        br_fdb_fini();
}

module_init(br_init)
module_exit(br_deinit)
MODULE_LICENSE("GPL");
MODULE_VERSION(BR_VERSION);
MODULE_ALIAS_RTNL_LINK("bridge");
MODULE_DESCRIPTION("Ethernet bridge driver");
MODULE_IMPORT_NS("NETDEV_INTERNAL");