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

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <linux/spinlock.h>
#include <linux/times.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/jhash.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <asm/unaligned.h>
#include <linux/if_vlan.h>
#include <net/switchdev.h>
#include <trace/events/bridge.h>
#include "br_private.h"

static const struct rhashtable_params br_fdb_rht_params = {
        .head_offset = offsetof(struct net_bridge_fdb_entry, rhnode),
        .key_offset = offsetof(struct net_bridge_fdb_entry, key),
        .key_len = sizeof(struct net_bridge_fdb_key),
        .automatic_shrinking = true,
};

static struct kmem_cache *br_fdb_cache __read_mostly;
static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
                      const unsigned char *addr, u16 vid);
static void fdb_notify(struct net_bridge *br,
                       const struct net_bridge_fdb_entry *, int, bool);

int __init br_fdb_init(void)
{
        br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
                                         sizeof(struct net_bridge_fdb_entry),
                                         0,
                                         SLAB_HWCACHE_ALIGN, NULL);
        if (!br_fdb_cache)
                return -ENOMEM;

        return 0;
}

void br_fdb_fini(void)
{
        kmem_cache_destroy(br_fdb_cache);
}

int br_fdb_hash_init(struct net_bridge *br)
{
        return rhashtable_init(&br->fdb_hash_tbl, &br_fdb_rht_params);
}

void br_fdb_hash_fini(struct net_bridge *br)
{
        rhashtable_destroy(&br->fdb_hash_tbl);
}

/* if topology_changing then use forward_delay (default 15 sec)
 * otherwise keep longer (default 5 minutes)
 */
static inline unsigned long hold_time(const struct net_bridge *br)
{
        return br->topology_change ? br->forward_delay : br->ageing_time;
}

static inline int has_expired(const struct net_bridge *br,
                                  const struct net_bridge_fdb_entry *fdb)
{
        return !test_bit(BR_FDB_STATIC, &fdb->flags) &&
               !test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags) &&
               time_before_eq(fdb->updated + hold_time(br), jiffies);
}

static void fdb_rcu_free(struct rcu_head *head)
{
        struct net_bridge_fdb_entry *ent
                = container_of(head, struct net_bridge_fdb_entry, rcu);
        kmem_cache_free(br_fdb_cache, ent);
}

static struct net_bridge_fdb_entry *fdb_find_rcu(struct rhashtable *tbl,
                                                 const unsigned char *addr,
                                                 __u16 vid)
{
        struct net_bridge_fdb_key key;

        WARN_ON_ONCE(!rcu_read_lock_held());

        key.vlan_id = vid;
        memcpy(key.addr.addr, addr, sizeof(key.addr.addr));

        return rhashtable_lookup(tbl, &key, br_fdb_rht_params);
}

/* requires bridge hash_lock */
static struct net_bridge_fdb_entry *br_fdb_find(struct net_bridge *br,
                                                const unsigned char *addr,
                                                __u16 vid)
{
        struct net_bridge_fdb_entry *fdb;

        lockdep_assert_held_once(&br->hash_lock);

        rcu_read_lock();
        fdb = fdb_find_rcu(&br->fdb_hash_tbl, addr, vid);
        rcu_read_unlock();

        return fdb;
}

struct net_device *br_fdb_find_port(const struct net_device *br_dev,
                                    const unsigned char *addr,
                                    __u16 vid)
{
        struct net_bridge_fdb_entry *f;
        struct net_device *dev = NULL;
        struct net_bridge *br;

        ASSERT_RTNL();

        if (!netif_is_bridge_master(br_dev))
                return NULL;

        br = netdev_priv(br_dev);
        rcu_read_lock();
        f = br_fdb_find_rcu(br, addr, vid);
        if (f && f->dst)
                dev = f->dst->dev;
        rcu_read_unlock();

        return dev;
}
EXPORT_SYMBOL_GPL(br_fdb_find_port);

struct net_bridge_fdb_entry *br_fdb_find_rcu(struct net_bridge *br,
                                             const unsigned char *addr,
                                             __u16 vid)
{
        return fdb_find_rcu(&br->fdb_hash_tbl, addr, vid);
}

/* When a static FDB entry is added, the mac address from the entry is
 * added to the bridge private HW address list and all required ports
 * are then updated with the new information.
 * Called under RTNL.
 */
static void fdb_add_hw_addr(struct net_bridge *br, const unsigned char *addr)
{
        int err;
        struct net_bridge_port *p;

        ASSERT_RTNL();

        list_for_each_entry(p, &br->port_list, list) {
                if (!br_promisc_port(p)) {
                        err = dev_uc_add(p->dev, addr);
                        if (err)
                                goto undo;
                }
        }

        return;
undo:
        list_for_each_entry_continue_reverse(p, &br->port_list, list) {
                if (!br_promisc_port(p))
                        dev_uc_del(p->dev, addr);
        }
}

/* When a static FDB entry is deleted, the HW address from that entry is
 * also removed from the bridge private HW address list and updates all
 * the ports with needed information.
 * Called under RTNL.
 */
static void fdb_del_hw_addr(struct net_bridge *br, const unsigned char *addr)
{
        struct net_bridge_port *p;

        ASSERT_RTNL();

        list_for_each_entry(p, &br->port_list, list) {
                if (!br_promisc_port(p))
                        dev_uc_del(p->dev, addr);
        }
}

static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f,
                       bool swdev_notify)
{
        trace_fdb_delete(br, f);

        if (test_bit(BR_FDB_STATIC, &f->flags))
                fdb_del_hw_addr(br, f->key.addr.addr);

        hlist_del_init_rcu(&f->fdb_node);
        rhashtable_remove_fast(&br->fdb_hash_tbl, &f->rhnode,
                               br_fdb_rht_params);
        fdb_notify(br, f, RTM_DELNEIGH, swdev_notify);
        call_rcu(&f->rcu, fdb_rcu_free);
}

/* Delete a local entry if no other port had the same address. */
static void fdb_delete_local(struct net_bridge *br,
                             const struct net_bridge_port *p,
                             struct net_bridge_fdb_entry *f)
{
        const unsigned char *addr = f->key.addr.addr;
        struct net_bridge_vlan_group *vg;
        const struct net_bridge_vlan *v;
        struct net_bridge_port *op;
        u16 vid = f->key.vlan_id;

        /* Maybe another port has same hw addr? */
        list_for_each_entry(op, &br->port_list, list) {
                vg = nbp_vlan_group(op);
                if (op != p && ether_addr_equal(op->dev->dev_addr, addr) &&
                    (!vid || br_vlan_find(vg, vid))) {
                        f->dst = op;
                        clear_bit(BR_FDB_ADDED_BY_USER, &f->flags);
                        return;
                }
        }

        vg = br_vlan_group(br);
        v = br_vlan_find(vg, vid);
        /* Maybe bridge device has same hw addr? */
        if (p && ether_addr_equal(br->dev->dev_addr, addr) &&
            (!vid || (v && br_vlan_should_use(v)))) {
                f->dst = NULL;
                clear_bit(BR_FDB_ADDED_BY_USER, &f->flags);
                return;
        }

        fdb_delete(br, f, true);
}

void br_fdb_find_delete_local(struct net_bridge *br,
                              const struct net_bridge_port *p,
                              const unsigned char *addr, u16 vid)
{
        struct net_bridge_fdb_entry *f;

        spin_lock_bh(&br->hash_lock);
        f = br_fdb_find(br, addr, vid);
        if (f && test_bit(BR_FDB_LOCAL, &f->flags) &&
            !test_bit(BR_FDB_ADDED_BY_USER, &f->flags) && f->dst == p)
                fdb_delete_local(br, p, f);
        spin_unlock_bh(&br->hash_lock);
}

void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
{
        struct net_bridge_vlan_group *vg;
        struct net_bridge_fdb_entry *f;
        struct net_bridge *br = p->br;
        struct net_bridge_vlan *v;

        spin_lock_bh(&br->hash_lock);
        vg = nbp_vlan_group(p);
        hlist_for_each_entry(f, &br->fdb_list, fdb_node) {
                if (f->dst == p && test_bit(BR_FDB_LOCAL, &f->flags) &&
                    !test_bit(BR_FDB_ADDED_BY_USER, &f->flags)) {
                        /* delete old one */
                        fdb_delete_local(br, p, f);

                        /* if this port has no vlan information
                         * configured, we can safely be done at
                         * this point.
                         */
                        if (!vg || !vg->num_vlans)
                                goto insert;
                }
        }

insert:
        /* insert new address,  may fail if invalid address or dup. */
        fdb_insert(br, p, newaddr, 0);

        if (!vg || !vg->num_vlans)
                goto done;

        /* Now add entries for every VLAN configured on the port.
         * This function runs under RTNL so the bitmap will not change
         * from under us.
         */
        list_for_each_entry(v, &vg->vlan_list, vlist)
                fdb_insert(br, p, newaddr, v->vid);

done:
        spin_unlock_bh(&br->hash_lock);
}

void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
{
        struct net_bridge_vlan_group *vg;
        struct net_bridge_fdb_entry *f;
        struct net_bridge_vlan *v;

        spin_lock_bh(&br->hash_lock);

        /* If old entry was unassociated with any port, then delete it. */
        f = br_fdb_find(br, br->dev->dev_addr, 0);
        if (f && test_bit(BR_FDB_LOCAL, &f->flags) &&
            !f->dst && !test_bit(BR_FDB_ADDED_BY_USER, &f->flags))
                fdb_delete_local(br, NULL, f);

        fdb_insert(br, NULL, newaddr, 0);
        vg = br_vlan_group(br);
        if (!vg || !vg->num_vlans)
                goto out;
        /* Now remove and add entries for every VLAN configured on the
         * bridge.  This function runs under RTNL so the bitmap will not
         * change from under us.
         */
        list_for_each_entry(v, &vg->vlan_list, vlist) {
                if (!br_vlan_should_use(v))
                        continue;
                f = br_fdb_find(br, br->dev->dev_addr, v->vid);
                if (f && test_bit(BR_FDB_LOCAL, &f->flags) &&
                    !f->dst && !test_bit(BR_FDB_ADDED_BY_USER, &f->flags))
                        fdb_delete_local(br, NULL, f);
                fdb_insert(br, NULL, newaddr, v->vid);
        }
out:
        spin_unlock_bh(&br->hash_lock);
}

void br_fdb_cleanup(struct work_struct *work)
{
        struct net_bridge *br = container_of(work, struct net_bridge,
                                             gc_work.work);
        struct net_bridge_fdb_entry *f = NULL;
        unsigned long delay = hold_time(br);
        unsigned long work_delay = delay;
        unsigned long now = jiffies;

        /* this part is tricky, in order to avoid blocking learning and
         * consequently forwarding, we rely on rcu to delete objects with
         * delayed freeing allowing us to continue traversing
         */
        rcu_read_lock();
        hlist_for_each_entry_rcu(f, &br->fdb_list, fdb_node) {
                unsigned long this_timer;

                if (test_bit(BR_FDB_STATIC, &f->flags) ||
                    test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &f->flags))
                        continue;
                this_timer = f->updated + delay;
                if (time_after(this_timer, now)) {
                        work_delay = min(work_delay, this_timer - now);
                } else {
                        spin_lock_bh(&br->hash_lock);
                        if (!hlist_unhashed(&f->fdb_node))
                                fdb_delete(br, f, true);
                        spin_unlock_bh(&br->hash_lock);
                }
        }
        rcu_read_unlock();

        /* Cleanup minimum 10 milliseconds apart */
        work_delay = max_t(unsigned long, work_delay, msecs_to_jiffies(10));
        mod_delayed_work(system_long_wq, &br->gc_work, work_delay);
}

/* Completely flush all dynamic entries in forwarding database.*/
void br_fdb_flush(struct net_bridge *br)
{
        struct net_bridge_fdb_entry *f;
        struct hlist_node *tmp;

        spin_lock_bh(&br->hash_lock);
        hlist_for_each_entry_safe(f, tmp, &br->fdb_list, fdb_node) {
                if (!test_bit(BR_FDB_STATIC, &f->flags))
                        fdb_delete(br, f, true);
        }
        spin_unlock_bh(&br->hash_lock);
}

/* Flush all entries referring to a specific port.
 * if do_all is set also flush static entries
 * if vid is set delete all entries that match the vlan_id
 */
void br_fdb_delete_by_port(struct net_bridge *br,
                           const struct net_bridge_port *p,
                           u16 vid,
                           int do_all)
{
        struct net_bridge_fdb_entry *f;
        struct hlist_node *tmp;

        spin_lock_bh(&br->hash_lock);
        hlist_for_each_entry_safe(f, tmp, &br->fdb_list, fdb_node) {
                if (f->dst != p)
                        continue;

                if (!do_all)
                        if (test_bit(BR_FDB_STATIC, &f->flags) ||
                            (vid && f->key.vlan_id != vid))
                                continue;

                if (test_bit(BR_FDB_LOCAL, &f->flags))
                        fdb_delete_local(br, p, f);
                else
                        fdb_delete(br, f, true);
        }
        spin_unlock_bh(&br->hash_lock);
}

#if IS_ENABLED(CONFIG_ATM_LANE)
/* Interface used by ATM LANE hook to test
 * if an addr is on some other bridge port */
int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
{
        struct net_bridge_fdb_entry *fdb;
        struct net_bridge_port *port;
        int ret;

        rcu_read_lock();
        port = br_port_get_rcu(dev);
        if (!port)
                ret = 0;
        else {
                fdb = br_fdb_find_rcu(port->br, addr, 0);
                ret = fdb && fdb->dst && fdb->dst->dev != dev &&
                        fdb->dst->state == BR_STATE_FORWARDING;
        }
        rcu_read_unlock();

        return ret;
}
#endif /* CONFIG_ATM_LANE */

/*
 * Fill buffer with forwarding table records in
 * the API format.
 */
int br_fdb_fillbuf(struct net_bridge *br, void *buf,
                   unsigned long maxnum, unsigned long skip)
{
        struct net_bridge_fdb_entry *f;
        struct __fdb_entry *fe = buf;
        int num = 0;

        memset(buf, 0, maxnum*sizeof(struct __fdb_entry));

        rcu_read_lock();
        hlist_for_each_entry_rcu(f, &br->fdb_list, fdb_node) {
                if (num >= maxnum)
                        break;

                if (has_expired(br, f))
                        continue;

                /* ignore pseudo entry for local MAC address */
                if (!f->dst)
                        continue;

                if (skip) {
                        --skip;
                        continue;
                }

                /* convert from internal format to API */
                memcpy(fe->mac_addr, f->key.addr.addr, ETH_ALEN);

                /* due to ABI compat need to split into hi/lo */
                fe->port_no = f->dst->port_no;
                fe->port_hi = f->dst->port_no >> 8;

                fe->is_local = test_bit(BR_FDB_LOCAL, &f->flags);
                if (!test_bit(BR_FDB_STATIC, &f->flags))
                        fe->ageing_timer_value = jiffies_delta_to_clock_t(jiffies - f->updated);
                ++fe;
                ++num;
        }
        rcu_read_unlock();

        return num;
}

static struct net_bridge_fdb_entry *fdb_create(struct net_bridge *br,
                                               struct net_bridge_port *source,
                                               const unsigned char *addr,
                                               __u16 vid,
                                               unsigned long flags)
{
        struct net_bridge_fdb_entry *fdb;

        fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
        if (fdb) {
                memcpy(fdb->key.addr.addr, addr, ETH_ALEN);
                fdb->dst = source;
                fdb->key.vlan_id = vid;
                fdb->flags = flags;
                fdb->updated = fdb->used = jiffies;
                if (rhashtable_lookup_insert_fast(&br->fdb_hash_tbl,
                                                  &fdb->rhnode,
                                                  br_fdb_rht_params)) {
                        kmem_cache_free(br_fdb_cache, fdb);
                        fdb = NULL;
                } else {
                        hlist_add_head_rcu(&fdb->fdb_node, &br->fdb_list);
                }
        }
        return fdb;
}

static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
                  const unsigned char *addr, u16 vid)
{
        struct net_bridge_fdb_entry *fdb;

        if (!is_valid_ether_addr(addr))
                return -EINVAL;

        fdb = br_fdb_find(br, addr, vid);
        if (fdb) {
                /* it is okay to have multiple ports with same
                 * address, just use the first one.
                 */
                if (test_bit(BR_FDB_LOCAL, &fdb->flags))
                        return 0;
                br_warn(br, "adding interface %s with same address as a received packet (addr:%pM, vlan:%u)\n",
                       source ? source->dev->name : br->dev->name, addr, vid);
                fdb_delete(br, fdb, true);
        }

        fdb = fdb_create(br, source, addr, vid,
                         BIT(BR_FDB_LOCAL) | BIT(BR_FDB_STATIC));
        if (!fdb)
                return -ENOMEM;

        fdb_add_hw_addr(br, addr);
        fdb_notify(br, fdb, RTM_NEWNEIGH, true);
        return 0;
}

/* Add entry for local address of interface */
int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
                  const unsigned char *addr, u16 vid)
{
        int ret;

        spin_lock_bh(&br->hash_lock);
        ret = fdb_insert(br, source, addr, vid);
        spin_unlock_bh(&br->hash_lock);
        return ret;
}

void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
                   const unsigned char *addr, u16 vid, unsigned long flags)
{
        struct net_bridge_fdb_entry *fdb;
        bool fdb_modified = false;

        /* some users want to always flood. */
        if (hold_time(br) == 0)
                return;

        fdb = fdb_find_rcu(&br->fdb_hash_tbl, addr, vid);
        if (likely(fdb)) {
                /* attempt to update an entry for a local interface */
                if (unlikely(test_bit(BR_FDB_LOCAL, &fdb->flags))) {
                        if (net_ratelimit())
                                br_warn(br, "received packet on %s with own address as source address (addr:%pM, vlan:%u)\n",
                                        source->dev->name, addr, vid);
                } else {
                        unsigned long now = jiffies;

                        /* fastpath: update of existing entry */
                        if (unlikely(source != fdb->dst &&
                                     !test_bit(BR_FDB_STICKY, &fdb->flags))) {
                                fdb->dst = source;
                                fdb_modified = true;
                                /* Take over HW learned entry */
                                if (unlikely(test_bit(BR_FDB_ADDED_BY_EXT_LEARN,
                                                      &fdb->flags)))
                                        clear_bit(BR_FDB_ADDED_BY_EXT_LEARN,
                                                  &fdb->flags);
                        }
                        if (now != fdb->updated)
                                fdb->updated = now;
                        if (unlikely(test_bit(BR_FDB_ADDED_BY_USER, &flags)))
                                set_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);
                        if (unlikely(fdb_modified)) {
                                trace_br_fdb_update(br, source, addr, vid, flags);
                                fdb_notify(br, fdb, RTM_NEWNEIGH, true);
                        }
                }
        } else {
                spin_lock(&br->hash_lock);
                fdb = fdb_create(br, source, addr, vid, flags);
                if (fdb) {
                        trace_br_fdb_update(br, source, addr, vid, flags);
                        fdb_notify(br, fdb, RTM_NEWNEIGH, true);
                }
                /* else  we lose race and someone else inserts
                 * it first, don't bother updating
                 */
                spin_unlock(&br->hash_lock);
        }
}

static int fdb_to_nud(const struct net_bridge *br,
                      const struct net_bridge_fdb_entry *fdb)
{
        if (test_bit(BR_FDB_LOCAL, &fdb->flags))
                return NUD_PERMANENT;
        else if (test_bit(BR_FDB_STATIC, &fdb->flags))
                return NUD_NOARP;
        else if (has_expired(br, fdb))
                return NUD_STALE;
        else
                return NUD_REACHABLE;
}

static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
                         const struct net_bridge_fdb_entry *fdb,
                         u32 portid, u32 seq, int type, unsigned int flags)
{
        unsigned long now = jiffies;
        struct nda_cacheinfo ci;
        struct nlmsghdr *nlh;
        struct ndmsg *ndm;

        nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
        if (nlh == NULL)
                return -EMSGSIZE;

        ndm = nlmsg_data(nlh);
        ndm->ndm_family  = AF_BRIDGE;
        ndm->ndm_pad1    = 0;
        ndm->ndm_pad2    = 0;
        ndm->ndm_flags   = 0;
        ndm->ndm_type    = 0;
        ndm->ndm_ifindex = fdb->dst ? fdb->dst->dev->ifindex : br->dev->ifindex;
        ndm->ndm_state   = fdb_to_nud(br, fdb);

        if (test_bit(BR_FDB_OFFLOADED, &fdb->flags))
                ndm->ndm_flags |= NTF_OFFLOADED;
        if (test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags))
                ndm->ndm_flags |= NTF_EXT_LEARNED;
        if (test_bit(BR_FDB_STICKY, &fdb->flags))
                ndm->ndm_flags |= NTF_STICKY;

        if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->key.addr))
                goto nla_put_failure;
        if (nla_put_u32(skb, NDA_MASTER, br->dev->ifindex))
                goto nla_put_failure;
        ci.ndm_used      = jiffies_to_clock_t(now - fdb->used);
        ci.ndm_confirmed = 0;
        ci.ndm_updated   = jiffies_to_clock_t(now - fdb->updated);
        ci.ndm_refcnt    = 0;
        if (nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
                goto nla_put_failure;

        if (fdb->key.vlan_id && nla_put(skb, NDA_VLAN, sizeof(u16),
                                        &fdb->key.vlan_id))
                goto nla_put_failure;

        nlmsg_end(skb, nlh);
        return 0;

nla_put_failure:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

static inline size_t fdb_nlmsg_size(void)
{
        return NLMSG_ALIGN(sizeof(struct ndmsg))
                + nla_total_size(ETH_ALEN) /* NDA_LLADDR */
                + nla_total_size(sizeof(u32)) /* NDA_MASTER */
                + nla_total_size(sizeof(u16)) /* NDA_VLAN */
                + nla_total_size(sizeof(struct nda_cacheinfo));
}

static void fdb_notify(struct net_bridge *br,
                       const struct net_bridge_fdb_entry *fdb, int type,
                       bool swdev_notify)
{
        struct net *net = dev_net(br->dev);
        struct sk_buff *skb;
        int err = -ENOBUFS;

        if (swdev_notify)
                br_switchdev_fdb_notify(fdb, type);

        skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
        if (skb == NULL)
                goto errout;

        err = fdb_fill_info(skb, br, fdb, 0, 0, type, 0);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in fdb_nlmsg_size() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
        return;
errout:
        rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
}

/* Dump information about entries, in response to GETNEIGH */
int br_fdb_dump(struct sk_buff *skb,
                struct netlink_callback *cb,
                struct net_device *dev,
                struct net_device *filter_dev,
                int *idx)
{
        struct net_bridge *br = netdev_priv(dev);
        struct net_bridge_fdb_entry *f;
        int err = 0;

        if (!(dev->priv_flags & IFF_EBRIDGE))
                return err;

        if (!filter_dev) {
                err = ndo_dflt_fdb_dump(skb, cb, dev, NULL, idx);
                if (err < 0)
                        return err;
        }

        rcu_read_lock();
        hlist_for_each_entry_rcu(f, &br->fdb_list, fdb_node) {
                if (*idx < cb->args[2])
                        goto skip;
                if (filter_dev && (!f->dst || f->dst->dev != filter_dev)) {
                        if (filter_dev != dev)
                                goto skip;
                        /* !f->dst is a special case for bridge
                         * It means the MAC belongs to the bridge
                         * Therefore need a little more filtering
                         * we only want to dump the !f->dst case
                         */
                        if (f->dst)
                                goto skip;
                }
                if (!filter_dev && f->dst)
                        goto skip;

                err = fdb_fill_info(skb, br, f,
                                    NETLINK_CB(cb->skb).portid,
                                    cb->nlh->nlmsg_seq,
                                    RTM_NEWNEIGH,
                                    NLM_F_MULTI);
                if (err < 0)
                        break;
skip:
                *idx += 1;
        }
        rcu_read_unlock();

        return err;
}

int br_fdb_get(struct sk_buff *skb,
               struct nlattr *tb[],
               struct net_device *dev,
               const unsigned char *addr,
               u16 vid, u32 portid, u32 seq,
               struct netlink_ext_ack *extack)
{
        struct net_bridge *br = netdev_priv(dev);
        struct net_bridge_fdb_entry *f;
        int err = 0;

        rcu_read_lock();
        f = br_fdb_find_rcu(br, addr, vid);
        if (!f) {
                NL_SET_ERR_MSG(extack, "Fdb entry not found");
                err = -ENOENT;
                goto errout;
        }

        err = fdb_fill_info(skb, br, f, portid, seq,
                            RTM_NEWNEIGH, 0);
errout:
        rcu_read_unlock();
        return err;
}

/* Update (create or replace) forwarding database entry */
static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
                         const u8 *addr, u16 state, u16 flags, u16 vid,
                         u8 ndm_flags)
{
        bool is_sticky = !!(ndm_flags & NTF_STICKY);
        struct net_bridge_fdb_entry *fdb;
        bool modified = false;

        /* If the port cannot learn allow only local and static entries */
        if (source && !(state & NUD_PERMANENT) && !(state & NUD_NOARP) &&
            !(source->state == BR_STATE_LEARNING ||
              source->state == BR_STATE_FORWARDING))
                return -EPERM;

        if (!source && !(state & NUD_PERMANENT)) {
                pr_info("bridge: RTM_NEWNEIGH %s without NUD_PERMANENT\n",
                        br->dev->name);
                return -EINVAL;
        }

        if (is_sticky && (state & NUD_PERMANENT))
                return -EINVAL;

        fdb = br_fdb_find(br, addr, vid);
        if (fdb == NULL) {
                if (!(flags & NLM_F_CREATE))
                        return -ENOENT;

                fdb = fdb_create(br, source, addr, vid, 0);
                if (!fdb)
                        return -ENOMEM;

                modified = true;
        } else {
                if (flags & NLM_F_EXCL)
                        return -EEXIST;

                if (fdb->dst != source) {
                        fdb->dst = source;
                        modified = true;
                }
        }

        if (fdb_to_nud(br, fdb) != state) {
                if (state & NUD_PERMANENT) {
                        set_bit(BR_FDB_LOCAL, &fdb->flags);
                        if (!test_and_set_bit(BR_FDB_STATIC, &fdb->flags))
                                fdb_add_hw_addr(br, addr);
                } else if (state & NUD_NOARP) {
                        clear_bit(BR_FDB_LOCAL, &fdb->flags);
                        if (!test_and_set_bit(BR_FDB_STATIC, &fdb->flags))
                                fdb_add_hw_addr(br, addr);
                } else {
                        clear_bit(BR_FDB_LOCAL, &fdb->flags);
                        if (test_and_clear_bit(BR_FDB_STATIC, &fdb->flags))
                                fdb_del_hw_addr(br, addr);
                }

                modified = true;
        }

        if (is_sticky != test_bit(BR_FDB_STICKY, &fdb->flags)) {
                change_bit(BR_FDB_STICKY, &fdb->flags);
                modified = true;
        }

        set_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);

        fdb->used = jiffies;
        if (modified) {
                fdb->updated = jiffies;
                fdb_notify(br, fdb, RTM_NEWNEIGH, true);
        }

        return 0;
}

static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge *br,
                        struct net_bridge_port *p, const unsigned char *addr,
                        u16 nlh_flags, u16 vid)
{
        int err = 0;

        if (ndm->ndm_flags & NTF_USE) {
                if (!p) {
                        pr_info("bridge: RTM_NEWNEIGH %s with NTF_USE is not supported\n",
                                br->dev->name);
                        return -EINVAL;
                }
                if (!nbp_state_should_learn(p))
                        return 0;

                local_bh_disable();
                rcu_read_lock();
                br_fdb_update(br, p, addr, vid, BIT(BR_FDB_ADDED_BY_USER));
                rcu_read_unlock();
                local_bh_enable();
        } else if (ndm->ndm_flags & NTF_EXT_LEARNED) {
                err = br_fdb_external_learn_add(br, p, addr, vid, true);
        } else {
                spin_lock_bh(&br->hash_lock);
                err = fdb_add_entry(br, p, addr, ndm->ndm_state,
                                    nlh_flags, vid, ndm->ndm_flags);
                spin_unlock_bh(&br->hash_lock);
        }

        return err;
}

/* Add new permanent fdb entry with RTM_NEWNEIGH */
int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
               struct net_device *dev,
               const unsigned char *addr, u16 vid, u16 nlh_flags,
               struct netlink_ext_ack *extack)
{
        struct net_bridge_vlan_group *vg;
        struct net_bridge_port *p = NULL;
        struct net_bridge_vlan *v;
        struct net_bridge *br = NULL;
        int err = 0;

        trace_br_fdb_add(ndm, dev, addr, vid, nlh_flags);

        if (!(ndm->ndm_state & (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE))) {
                pr_info("bridge: RTM_NEWNEIGH with invalid state %#x\n", ndm->ndm_state);
                return -EINVAL;
        }

        if (is_zero_ether_addr(addr)) {
                pr_info("bridge: RTM_NEWNEIGH with invalid ether address\n");
                return -EINVAL;
        }

        if (dev->priv_flags & IFF_EBRIDGE) {
                br = netdev_priv(dev);
                vg = br_vlan_group(br);
        } else {
                p = br_port_get_rtnl(dev);
                if (!p) {
                        pr_info("bridge: RTM_NEWNEIGH %s not a bridge port\n",
                                dev->name);
                        return -EINVAL;
                }
                br = p->br;
                vg = nbp_vlan_group(p);
        }

        if (vid) {
                v = br_vlan_find(vg, vid);
                if (!v || !br_vlan_should_use(v)) {
                        pr_info("bridge: RTM_NEWNEIGH with unconfigured vlan %d on %s\n", vid, dev->name);
                        return -EINVAL;
                }

                /* VID was specified, so use it. */
                err = __br_fdb_add(ndm, br, p, addr, nlh_flags, vid);
        } else {
                err = __br_fdb_add(ndm, br, p, addr, nlh_flags, 0);
                if (err || !vg || !vg->num_vlans)
                        goto out;

                /* We have vlans configured on this port and user didn't
                 * specify a VLAN.  To be nice, add/update entry for every
                 * vlan on this port.
                 */
                list_for_each_entry(v, &vg->vlan_list, vlist) {
                        if (!br_vlan_should_use(v))
                                continue;
                        err = __br_fdb_add(ndm, br, p, addr, nlh_flags, v->vid);
                        if (err)
                                goto out;
                }
        }

out:
        return err;
}

static int fdb_delete_by_addr_and_port(struct net_bridge *br,
                                       const struct net_bridge_port *p,
                                       const u8 *addr, u16 vlan)
{
        struct net_bridge_fdb_entry *fdb;

        fdb = br_fdb_find(br, addr, vlan);
        if (!fdb || fdb->dst != p)
                return -ENOENT;

        fdb_delete(br, fdb, true);

        return 0;
}

static int __br_fdb_delete(struct net_bridge *br,
                           const struct net_bridge_port *p,
                           const unsigned char *addr, u16 vid)
{
        int err;

        spin_lock_bh(&br->hash_lock);
        err = fdb_delete_by_addr_and_port(br, p, addr, vid);
        spin_unlock_bh(&br->hash_lock);

        return err;
}

/* Remove neighbor entry with RTM_DELNEIGH */
int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
                  struct net_device *dev,
                  const unsigned char *addr, u16 vid)
{
        struct net_bridge_vlan_group *vg;
        struct net_bridge_port *p = NULL;
        struct net_bridge_vlan *v;
        struct net_bridge *br;
        int err;

        if (dev->priv_flags & IFF_EBRIDGE) {
                br = netdev_priv(dev);
                vg = br_vlan_group(br);
        } else {
                p = br_port_get_rtnl(dev);
                if (!p) {
                        pr_info("bridge: RTM_DELNEIGH %s not a bridge port\n",
                                dev->name);
                        return -EINVAL;
                }
                vg = nbp_vlan_group(p);
                br = p->br;
        }

        if (vid) {
                v = br_vlan_find(vg, vid);
                if (!v) {
                        pr_info("bridge: RTM_DELNEIGH with unconfigured vlan %d on %s\n", vid, dev->name);
                        return -EINVAL;
                }

                err = __br_fdb_delete(br, p, addr, vid);
        } else {
                err = -ENOENT;
                err &= __br_fdb_delete(br, p, addr, 0);
                if (!vg || !vg->num_vlans)
                        return err;

                list_for_each_entry(v, &vg->vlan_list, vlist) {
                        if (!br_vlan_should_use(v))
                                continue;
                        err &= __br_fdb_delete(br, p, addr, v->vid);
                }
        }

        return err;
}

int br_fdb_sync_static(struct net_bridge *br, struct net_bridge_port *p)
{
        struct net_bridge_fdb_entry *f, *tmp;
        int err = 0;

        ASSERT_RTNL();

        /* the key here is that static entries change only under rtnl */
        rcu_read_lock();
        hlist_for_each_entry_rcu(f, &br->fdb_list, fdb_node) {
                /* We only care for static entries */
                if (!test_bit(BR_FDB_STATIC, &f->flags))
                        continue;
                err = dev_uc_add(p->dev, f->key.addr.addr);
                if (err)
                        goto rollback;
        }
done:
        rcu_read_unlock();

        return err;

rollback:
        hlist_for_each_entry_rcu(tmp, &br->fdb_list, fdb_node) {
                /* We only care for static entries */
                if (!test_bit(BR_FDB_STATIC, &tmp->flags))
                        continue;
                if (tmp == f)
                        break;
                dev_uc_del(p->dev, tmp->key.addr.addr);
        }

        goto done;
}

void br_fdb_unsync_static(struct net_bridge *br, struct net_bridge_port *p)
{
        struct net_bridge_fdb_entry *f;

        ASSERT_RTNL();

        rcu_read_lock();
        hlist_for_each_entry_rcu(f, &br->fdb_list, fdb_node) {
                /* We only care for static entries */
                if (!test_bit(BR_FDB_STATIC, &f->flags))
                        continue;

                dev_uc_del(p->dev, f->key.addr.addr);
        }
        rcu_read_unlock();
}

int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
                              const unsigned char *addr, u16 vid,
                              bool swdev_notify)
{
        struct net_bridge_fdb_entry *fdb;
        bool modified = false;
        int err = 0;

        trace_br_fdb_external_learn_add(br, p, addr, vid);

        spin_lock_bh(&br->hash_lock);

        fdb = br_fdb_find(br, addr, vid);
        if (!fdb) {
                unsigned long flags = BIT(BR_FDB_ADDED_BY_EXT_LEARN);

                if (swdev_notify)
                        flags |= BIT(BR_FDB_ADDED_BY_USER);
                fdb = fdb_create(br, p, addr, vid, flags);
                if (!fdb) {
                        err = -ENOMEM;
                        goto err_unlock;
                }
                fdb_notify(br, fdb, RTM_NEWNEIGH, swdev_notify);
        } else {
                fdb->updated = jiffies;

                if (fdb->dst != p) {
                        fdb->dst = p;
                        modified = true;
                }

                if (test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags)) {
                        /* Refresh entry */
                        fdb->used = jiffies;
                } else if (!test_bit(BR_FDB_ADDED_BY_USER, &fdb->flags)) {
                        /* Take over SW learned entry */
                        set_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags);
                        modified = true;
                }

                if (swdev_notify)
                        set_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);

                if (modified)
                        fdb_notify(br, fdb, RTM_NEWNEIGH, swdev_notify);
        }

err_unlock:
        spin_unlock_bh(&br->hash_lock);

        return err;
}

int br_fdb_external_learn_del(struct net_bridge *br, struct net_bridge_port *p,
                              const unsigned char *addr, u16 vid,
                              bool swdev_notify)
{
        struct net_bridge_fdb_entry *fdb;
        int err = 0;

        spin_lock_bh(&br->hash_lock);

        fdb = br_fdb_find(br, addr, vid);
        if (fdb && test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags))
                fdb_delete(br, fdb, swdev_notify);
        else
                err = -ENOENT;

        spin_unlock_bh(&br->hash_lock);

        return err;
}

void br_fdb_offloaded_set(struct net_bridge *br, struct net_bridge_port *p,
                          const unsigned char *addr, u16 vid, bool offloaded)
{
        struct net_bridge_fdb_entry *fdb;

        spin_lock_bh(&br->hash_lock);

        fdb = br_fdb_find(br, addr, vid);
        if (fdb && offloaded != test_bit(BR_FDB_OFFLOADED, &fdb->flags))
                change_bit(BR_FDB_OFFLOADED, &fdb->flags);

        spin_unlock_bh(&br->hash_lock);
}

void br_fdb_clear_offload(const struct net_device *dev, u16 vid)
{
        struct net_bridge_fdb_entry *f;
        struct net_bridge_port *p;

        ASSERT_RTNL();

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

        spin_lock_bh(&p->br->hash_lock);
        hlist_for_each_entry(f, &p->br->fdb_list, fdb_node) {
                if (f->dst == p && f->key.vlan_id == vid)
                        clear_bit(BR_FDB_OFFLOADED, &f->flags);
        }
        spin_unlock_bh(&p->br->hash_lock);
}
EXPORT_SYMBOL_GPL(br_fdb_clear_offload);