br_multicast.c

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/*
 * Bridge multicast support.
 *
 * Copyright (c) 2010 Herbert Xu <[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/err.h>
#include <linux/if_ether.h>
#include <linux/igmp.h>
#include <linux/jhash.h>
#include <linux/kernel.h>
#include <linux/log2.h>
#include <linux/netdevice.h>
#include <linux/netfilter_bridge.h>
#include <linux/random.h>
#include <linux/rculist.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <net/ip.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/mld.h>
#include <net/addrconf.h>
#include <net/ip6_checksum.h>
#endif

#include "br_private.h"

#define mlock_dereference(X, br) \
    rcu_dereference_protected(X, lockdep_is_held(&br->multicast_lock))

static void br_multicast_start_querier(struct net_bridge *br);

#if IS_ENABLED(CONFIG_IPV6)
static inline int ipv6_is_transient_multicast(const struct in6_addr *addr)
{
    if (ipv6_addr_is_multicast(addr) && IPV6_ADDR_MC_FLAG_TRANSIENT(addr))
        return 1;
    return 0;
}
#endif

static inline int br_ip_equal(const struct br_ip *a, const struct br_ip *b)
{
    if (a->proto != b->proto)
        return 0;
    switch (a->proto) {
    case htons(ETH_P_IP):
        return a->u.ip4 == b->u.ip4;
#if IS_ENABLED(CONFIG_IPV6)
    case htons(ETH_P_IPV6):
        return ipv6_addr_equal(&a->u.ip6, &b->u.ip6);
#endif
    }
    return 0;
}

static inline int __br_ip4_hash(struct net_bridge_mdb_htable *mdb, __be32 ip)
{
    return jhash_1word(mdb->secret, (__force u32)ip) & (mdb->max - 1);
}

#if IS_ENABLED(CONFIG_IPV6)
static inline int __br_ip6_hash(struct net_bridge_mdb_htable *mdb,
                const struct in6_addr *ip)
{
    return jhash2((__force u32 *)ip->s6_addr32, 4, mdb->secret) & (mdb->max - 1);
}
#endif

static inline int br_ip_hash(struct net_bridge_mdb_htable *mdb,
                 struct br_ip *ip)
{
    switch (ip->proto) {
    case htons(ETH_P_IP):
        return __br_ip4_hash(mdb, ip->u.ip4);
#if IS_ENABLED(CONFIG_IPV6)
    case htons(ETH_P_IPV6):
        return __br_ip6_hash(mdb, &ip->u.ip6);
#endif
    }
    return 0;
}

static struct net_bridge_mdb_entry *__br_mdb_ip_get(
    struct net_bridge_mdb_htable *mdb, struct br_ip *dst, int hash)
{
    struct net_bridge_mdb_entry *mp;
    struct hlist_node *p;

    hlist_for_each_entry_rcu(mp, p, &mdb->mhash[hash], hlist[mdb->ver]) {
        if (br_ip_equal(&mp->addr, dst))
            return mp;
    }

    return NULL;
}

static struct net_bridge_mdb_entry *br_mdb_ip_get(
    struct net_bridge_mdb_htable *mdb, struct br_ip *dst)
{
    if (!mdb)
        return NULL;

    return __br_mdb_ip_get(mdb, dst, br_ip_hash(mdb, dst));
}

static struct net_bridge_mdb_entry *br_mdb_ip4_get(
    struct net_bridge_mdb_htable *mdb, __be32 dst)
{
    struct br_ip br_dst;

    br_dst.u.ip4 = dst;
    br_dst.proto = htons(ETH_P_IP);

    return br_mdb_ip_get(mdb, &br_dst);
}

#if IS_ENABLED(CONFIG_IPV6)
static struct net_bridge_mdb_entry *br_mdb_ip6_get(
    struct net_bridge_mdb_htable *mdb, const struct in6_addr *dst)
{
    struct br_ip br_dst;

    br_dst.u.ip6 = *dst;
    br_dst.proto = htons(ETH_P_IPV6);

    return br_mdb_ip_get(mdb, &br_dst);
}
#endif

struct net_bridge_mdb_entry *br_mdb_get(struct net_bridge *br,
                    struct sk_buff *skb)
{
    struct net_bridge_mdb_htable *mdb = rcu_dereference(br->mdb);
    struct br_ip ip;

    if (br->multicast_disabled)
        return NULL;

    if (BR_INPUT_SKB_CB(skb)->igmp)
        return NULL;

    ip.proto = skb->protocol;

    switch (skb->protocol) {
    case htons(ETH_P_IP):
        ip.u.ip4 = ip_hdr(skb)->daddr;
        break;
#if IS_ENABLED(CONFIG_IPV6)
    case htons(ETH_P_IPV6):
        ip.u.ip6 = ipv6_hdr(skb)->daddr;
        break;
#endif
    default:
        return NULL;
    }

    return br_mdb_ip_get(mdb, &ip);
}

static void br_mdb_free(struct rcu_head *head)
{
    struct net_bridge_mdb_htable *mdb =
        container_of(head, struct net_bridge_mdb_htable, rcu);
    struct net_bridge_mdb_htable *old = mdb->old;

    mdb->old = NULL;
    kfree(old->mhash);
    kfree(old);
}

static int br_mdb_copy(struct net_bridge_mdb_htable *new,
               struct net_bridge_mdb_htable *old,
               int elasticity)
{
    struct net_bridge_mdb_entry *mp;
    struct hlist_node *p;
    int maxlen;
    int len;
    int i;

    for (i = 0; i < old->max; i++)
        hlist_for_each_entry(mp, p, &old->mhash[i], hlist[old->ver])
            hlist_add_head(&mp->hlist[new->ver],
                       &new->mhash[br_ip_hash(new, &mp->addr)]);

    if (!elasticity)
        return 0;

    maxlen = 0;
    for (i = 0; i < new->max; i++) {
        len = 0;
        hlist_for_each_entry(mp, p, &new->mhash[i], hlist[new->ver])
            len++;
        if (len > maxlen)
            maxlen = len;
    }

    return maxlen > elasticity ? -EINVAL : 0;
}

static void br_multicast_free_pg(struct rcu_head *head)
{
    struct net_bridge_port_group *p =
        container_of(head, struct net_bridge_port_group, rcu);

    kfree(p);
}

static void br_multicast_free_group(struct rcu_head *head)
{
    struct net_bridge_mdb_entry *mp =
        container_of(head, struct net_bridge_mdb_entry, rcu);

    kfree(mp);
}

static void br_multicast_group_expired(unsigned long data)
{
    struct net_bridge_mdb_entry *mp = (void *)data;
    struct net_bridge *br = mp->br;
    struct net_bridge_mdb_htable *mdb;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev) || timer_pending(&mp->timer))
        goto out;

    mp->mglist = false;

    if (mp->ports)
        goto out;

    mdb = mlock_dereference(br->mdb, br);

    hlist_del_rcu(&mp->hlist[mdb->ver]);
    mdb->size--;

    call_rcu_bh(&mp->rcu, br_multicast_free_group);

out:
    spin_unlock(&br->multicast_lock);
}

static void br_multicast_del_pg(struct net_bridge *br,
                struct net_bridge_port_group *pg)
{
    struct net_bridge_mdb_htable *mdb;
    struct net_bridge_mdb_entry *mp;
    struct net_bridge_port_group *p;
    struct net_bridge_port_group __rcu **pp;

    mdb = mlock_dereference(br->mdb, br);

    mp = br_mdb_ip_get(mdb, &pg->addr);
    if (WARN_ON(!mp))
        return;

    for (pp = &mp->ports;
         (p = mlock_dereference(*pp, br)) != NULL;
         pp = &p->next) {
        if (p != pg)
            continue;

        rcu_assign_pointer(*pp, p->next);
        hlist_del_init(&p->mglist);
        del_timer(&p->timer);
        call_rcu_bh(&p->rcu, br_multicast_free_pg);

        if (!mp->ports && !mp->mglist &&
            netif_running(br->dev))
            mod_timer(&mp->timer, jiffies);

        return;
    }

    WARN_ON(1);
}

static void br_multicast_port_group_expired(unsigned long data)
{
    struct net_bridge_port_group *pg = (void *)data;
    struct net_bridge *br = pg->port->br;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev) || timer_pending(&pg->timer) ||
        hlist_unhashed(&pg->mglist))
        goto out;

    br_multicast_del_pg(br, pg);

out:
    spin_unlock(&br->multicast_lock);
}

static int br_mdb_rehash(struct net_bridge_mdb_htable __rcu **mdbp, int max,
             int elasticity)
{
    struct net_bridge_mdb_htable *old = rcu_dereference_protected(*mdbp, 1);
    struct net_bridge_mdb_htable *mdb;
    int err;

    mdb = kmalloc(sizeof(*mdb), GFP_ATOMIC);
    if (!mdb)
        return -ENOMEM;

    mdb->max = max;
    mdb->old = old;

    mdb->mhash = kzalloc(max * sizeof(*mdb->mhash), GFP_ATOMIC);
    if (!mdb->mhash) {
        kfree(mdb);
        return -ENOMEM;
    }

    mdb->size = old ? old->size : 0;
    mdb->ver = old ? old->ver ^ 1 : 0;

    if (!old || elasticity)
        get_random_bytes(&mdb->secret, sizeof(mdb->secret));
    else
        mdb->secret = old->secret;

    if (!old)
        goto out;

    err = br_mdb_copy(mdb, old, elasticity);
    if (err) {
        kfree(mdb->mhash);
        kfree(mdb);
        return err;
    }

    call_rcu_bh(&mdb->rcu, br_mdb_free);

out:
    rcu_assign_pointer(*mdbp, mdb);

    return 0;
}

static struct sk_buff *br_ip4_multicast_alloc_query(struct net_bridge *br,
                            __be32 group)
{
    struct sk_buff *skb;
    struct igmphdr *ih;
    struct ethhdr *eth;
    struct iphdr *iph;

    skb = netdev_alloc_skb_ip_align(br->dev, sizeof(*eth) + sizeof(*iph) +
                         sizeof(*ih) + 4);
    if (!skb)
        goto out;

    skb->protocol = htons(ETH_P_IP);

    skb_reset_mac_header(skb);
    eth = eth_hdr(skb);

    memcpy(eth->h_source, br->dev->dev_addr, 6);
    eth->h_dest[0] = 1;
    eth->h_dest[1] = 0;
    eth->h_dest[2] = 0x5e;
    eth->h_dest[3] = 0;
    eth->h_dest[4] = 0;
    eth->h_dest[5] = 1;
    eth->h_proto = htons(ETH_P_IP);
    skb_put(skb, sizeof(*eth));

    skb_set_network_header(skb, skb->len);
    iph = ip_hdr(skb);

    iph->version = 4;
    iph->ihl = 6;
    iph->tos = 0xc0;
    iph->tot_len = htons(sizeof(*iph) + sizeof(*ih) + 4);
    iph->id = 0;
    iph->frag_off = htons(IP_DF);
    iph->ttl = 1;
    iph->protocol = IPPROTO_IGMP;
    iph->saddr = 0;
    iph->daddr = htonl(INADDR_ALLHOSTS_GROUP);
    ((u8 *)&iph[1])[0] = IPOPT_RA;
    ((u8 *)&iph[1])[1] = 4;
    ((u8 *)&iph[1])[2] = 0;
    ((u8 *)&iph[1])[3] = 0;
    ip_send_check(iph);
    skb_put(skb, 24);

    skb_set_transport_header(skb, skb->len);
    ih = igmp_hdr(skb);
    ih->type = IGMP_HOST_MEMBERSHIP_QUERY;
    ih->code = (group ? br->multicast_last_member_interval :
                br->multicast_query_response_interval) /
           (HZ / IGMP_TIMER_SCALE);
    ih->group = group;
    ih->csum = 0;
    ih->csum = ip_compute_csum((void *)ih, sizeof(struct igmphdr));
    skb_put(skb, sizeof(*ih));

    __skb_pull(skb, sizeof(*eth));

out:
    return skb;
}

#if IS_ENABLED(CONFIG_IPV6)
static struct sk_buff *br_ip6_multicast_alloc_query(struct net_bridge *br,
                            const struct in6_addr *group)
{
    struct sk_buff *skb;
    struct ipv6hdr *ip6h;
    struct mld_msg *mldq;
    struct ethhdr *eth;
    u8 *hopopt;
    unsigned long interval;

    skb = netdev_alloc_skb_ip_align(br->dev, sizeof(*eth) + sizeof(*ip6h) +
                         8 + sizeof(*mldq));
    if (!skb)
        goto out;

    skb->protocol = htons(ETH_P_IPV6);

    /* Ethernet header */
    skb_reset_mac_header(skb);
    eth = eth_hdr(skb);

    memcpy(eth->h_source, br->dev->dev_addr, 6);
    eth->h_proto = htons(ETH_P_IPV6);
    skb_put(skb, sizeof(*eth));

    /* IPv6 header + HbH option */
    skb_set_network_header(skb, skb->len);
    ip6h = ipv6_hdr(skb);

    *(__force __be32 *)ip6h = htonl(0x60000000);
    ip6h->payload_len = htons(8 + sizeof(*mldq));
    ip6h->nexthdr = IPPROTO_HOPOPTS;
    ip6h->hop_limit = 1;
    ipv6_addr_set(&ip6h->daddr, htonl(0xff020000), 0, 0, htonl(1));
    if (ipv6_dev_get_saddr(dev_net(br->dev), br->dev, &ip6h->daddr, 0,
                   &ip6h->saddr)) {
        kfree_skb(skb);
        return NULL;
    }
    ipv6_eth_mc_map(&ip6h->daddr, eth->h_dest);

    hopopt = (u8 *)(ip6h + 1);
    hopopt[0] = IPPROTO_ICMPV6;     /* next hdr */
    hopopt[1] = 0;              /* length of HbH */
    hopopt[2] = IPV6_TLV_ROUTERALERT;   /* Router Alert */
    hopopt[3] = 2;              /* Length of RA Option */
    hopopt[4] = 0;              /* Type = 0x0000 (MLD) */
    hopopt[5] = 0;
    hopopt[6] = IPV6_TLV_PAD1;      /* Pad1 */
    hopopt[7] = IPV6_TLV_PAD1;      /* Pad1 */

    skb_put(skb, sizeof(*ip6h) + 8);

    /* ICMPv6 */
    skb_set_transport_header(skb, skb->len);
    mldq = (struct mld_msg *) icmp6_hdr(skb);

    interval = ipv6_addr_any(group) ? br->multicast_last_member_interval :
                      br->multicast_query_response_interval;

    mldq->mld_type = ICMPV6_MGM_QUERY;
    mldq->mld_code = 0;
    mldq->mld_cksum = 0;
    mldq->mld_maxdelay = htons((u16)jiffies_to_msecs(interval));
    mldq->mld_reserved = 0;
    mldq->mld_mca = *group;

    /* checksum */
    mldq->mld_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
                      sizeof(*mldq), IPPROTO_ICMPV6,
                      csum_partial(mldq,
                               sizeof(*mldq), 0));
    skb_put(skb, sizeof(*mldq));

    __skb_pull(skb, sizeof(*eth));

out:
    return skb;
}
#endif

static struct sk_buff *br_multicast_alloc_query(struct net_bridge *br,
                        struct br_ip *addr)
{
    switch (addr->proto) {
    case htons(ETH_P_IP):
        return br_ip4_multicast_alloc_query(br, addr->u.ip4);
#if IS_ENABLED(CONFIG_IPV6)
    case htons(ETH_P_IPV6):
        return br_ip6_multicast_alloc_query(br, &addr->u.ip6);
#endif
    }
    return NULL;
}

static struct net_bridge_mdb_entry *br_multicast_get_group(
    struct net_bridge *br, struct net_bridge_port *port,
    struct br_ip *group, int hash)
{
    struct net_bridge_mdb_htable *mdb;
    struct net_bridge_mdb_entry *mp;
    struct hlist_node *p;
    unsigned int count = 0;
    unsigned int max;
    int elasticity;
    int err;

    mdb = rcu_dereference_protected(br->mdb, 1);
    hlist_for_each_entry(mp, p, &mdb->mhash[hash], hlist[mdb->ver]) {
        count++;
        if (unlikely(br_ip_equal(group, &mp->addr)))
            return mp;
    }

    elasticity = 0;
    max = mdb->max;

    if (unlikely(count > br->hash_elasticity && count)) {
        if (net_ratelimit())
            br_info(br, "Multicast hash table "
                "chain limit reached: %s\n",
                port ? port->dev->name : br->dev->name);

        elasticity = br->hash_elasticity;
    }

    if (mdb->size >= max) {
        max *= 2;
        if (unlikely(max > br->hash_max)) {
            br_warn(br, "Multicast hash table maximum of %d "
                "reached, disabling snooping: %s\n",
                br->hash_max,
                port ? port->dev->name : br->dev->name);
            err = -E2BIG;
disable:
            br->multicast_disabled = 1;
            goto err;
        }
    }

    if (max > mdb->max || elasticity) {
        if (mdb->old) {
            if (net_ratelimit())
                br_info(br, "Multicast hash table "
                    "on fire: %s\n",
                    port ? port->dev->name : br->dev->name);
            err = -EEXIST;
            goto err;
        }

        err = br_mdb_rehash(&br->mdb, max, elasticity);
        if (err) {
            br_warn(br, "Cannot rehash multicast "
                "hash table, disabling snooping: %s, %d, %d\n",
                port ? port->dev->name : br->dev->name,
                mdb->size, err);
            goto disable;
        }

        err = -EAGAIN;
        goto err;
    }

    return NULL;

err:
    mp = ERR_PTR(err);
    return mp;
}

static struct net_bridge_mdb_entry *br_multicast_new_group(
    struct net_bridge *br, struct net_bridge_port *port,
    struct br_ip *group)
{
    struct net_bridge_mdb_htable *mdb;
    struct net_bridge_mdb_entry *mp;
    int hash;
    int err;

    mdb = rcu_dereference_protected(br->mdb, 1);
    if (!mdb) {
        err = br_mdb_rehash(&br->mdb, BR_HASH_SIZE, 0);
        if (err)
            return ERR_PTR(err);
        goto rehash;
    }

    hash = br_ip_hash(mdb, group);
    mp = br_multicast_get_group(br, port, group, hash);
    switch (PTR_ERR(mp)) {
    case 0:
        break;

    case -EAGAIN:
rehash:
        mdb = rcu_dereference_protected(br->mdb, 1);
        hash = br_ip_hash(mdb, group);
        break;

    default:
        goto out;
    }

    mp = kzalloc(sizeof(*mp), GFP_ATOMIC);
    if (unlikely(!mp))
        return ERR_PTR(-ENOMEM);

    mp->br = br;
    mp->addr = *group;
    setup_timer(&mp->timer, br_multicast_group_expired,
            (unsigned long)mp);

    hlist_add_head_rcu(&mp->hlist[mdb->ver], &mdb->mhash[hash]);
    mdb->size++;

out:
    return mp;
}

static int br_multicast_add_group(struct net_bridge *br,
                  struct net_bridge_port *port,
                  struct br_ip *group)
{
    struct net_bridge_mdb_entry *mp;
    struct net_bridge_port_group *p;
    struct net_bridge_port_group __rcu **pp;
    unsigned long now = jiffies;
    int err;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev) ||
        (port && port->state == BR_STATE_DISABLED))
        goto out;

    mp = br_multicast_new_group(br, port, group);
    err = PTR_ERR(mp);
    if (IS_ERR(mp))
        goto err;

    if (!port) {
        mp->mglist = true;
        mod_timer(&mp->timer, now + br->multicast_membership_interval);
        goto out;
    }

    for (pp = &mp->ports;
         (p = mlock_dereference(*pp, br)) != NULL;
         pp = &p->next) {
        if (p->port == port)
            goto found;
        if ((unsigned long)p->port < (unsigned long)port)
            break;
    }

    p = kzalloc(sizeof(*p), GFP_ATOMIC);
    err = -ENOMEM;
    if (unlikely(!p))
        goto err;

    p->addr = *group;
    p->port = port;
    p->next = *pp;
    hlist_add_head(&p->mglist, &port->mglist);
    setup_timer(&p->timer, br_multicast_port_group_expired,
            (unsigned long)p);

    rcu_assign_pointer(*pp, p);

found:
    mod_timer(&p->timer, now + br->multicast_membership_interval);
out:
    err = 0;

err:
    spin_unlock(&br->multicast_lock);
    return err;
}

static int br_ip4_multicast_add_group(struct net_bridge *br,
                      struct net_bridge_port *port,
                      __be32 group)
{
    struct br_ip br_group;

    if (ipv4_is_local_multicast(group))
        return 0;

    br_group.u.ip4 = group;
    br_group.proto = htons(ETH_P_IP);

    return br_multicast_add_group(br, port, &br_group);
}

#if IS_ENABLED(CONFIG_IPV6)
static int br_ip6_multicast_add_group(struct net_bridge *br,
                      struct net_bridge_port *port,
                      const struct in6_addr *group)
{
    struct br_ip br_group;

    if (!ipv6_is_transient_multicast(group))
        return 0;

    br_group.u.ip6 = *group;
    br_group.proto = htons(ETH_P_IPV6);

    return br_multicast_add_group(br, port, &br_group);
}
#endif

static void br_multicast_router_expired(unsigned long data)
{
    struct net_bridge_port *port = (void *)data;
    struct net_bridge *br = port->br;

    spin_lock(&br->multicast_lock);
    if (port->multicast_router != 1 ||
        timer_pending(&port->multicast_router_timer) ||
        hlist_unhashed(&port->rlist))
        goto out;

    hlist_del_init_rcu(&port->rlist);

out:
    spin_unlock(&br->multicast_lock);
}

static void br_multicast_local_router_expired(unsigned long data)
{
}

static void br_multicast_querier_expired(unsigned long data)
{
    struct net_bridge *br = (void *)data;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev) || br->multicast_disabled)
        goto out;

    br_multicast_start_querier(br);

out:
    spin_unlock(&br->multicast_lock);
}

static void __br_multicast_send_query(struct net_bridge *br,
                      struct net_bridge_port *port,
                      struct br_ip *ip)
{
    struct sk_buff *skb;

    skb = br_multicast_alloc_query(br, ip);
    if (!skb)
        return;

    if (port) {
        __skb_push(skb, sizeof(struct ethhdr));
        skb->dev = port->dev;
        NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
            dev_queue_xmit);
    } else
        netif_rx(skb);
}

static void br_multicast_send_query(struct net_bridge *br,
                    struct net_bridge_port *port, u32 sent)
{
    unsigned long time;
    struct br_ip br_group;

    if (!netif_running(br->dev) || br->multicast_disabled ||
        !br->multicast_querier ||
        timer_pending(&br->multicast_querier_timer))
        return;

    memset(&br_group.u, 0, sizeof(br_group.u));

    br_group.proto = htons(ETH_P_IP);
    __br_multicast_send_query(br, port, &br_group);

#if IS_ENABLED(CONFIG_IPV6)
    br_group.proto = htons(ETH_P_IPV6);
    __br_multicast_send_query(br, port, &br_group);
#endif

    time = jiffies;
    time += sent < br->multicast_startup_query_count ?
        br->multicast_startup_query_interval :
        br->multicast_query_interval;
    mod_timer(port ? &port->multicast_query_timer :
             &br->multicast_query_timer, time);
}

static void br_multicast_port_query_expired(unsigned long data)
{
    struct net_bridge_port *port = (void *)data;
    struct net_bridge *br = port->br;

    spin_lock(&br->multicast_lock);
    if (port->state == BR_STATE_DISABLED ||
        port->state == BR_STATE_BLOCKING)
        goto out;

    if (port->multicast_startup_queries_sent <
        br->multicast_startup_query_count)
        port->multicast_startup_queries_sent++;

    br_multicast_send_query(port->br, port,
                port->multicast_startup_queries_sent);

out:
    spin_unlock(&br->multicast_lock);
}

void br_multicast_add_port(struct net_bridge_port *port)
{
    port->multicast_router = 1;

    setup_timer(&port->multicast_router_timer, br_multicast_router_expired,
            (unsigned long)port);
    setup_timer(&port->multicast_query_timer,
            br_multicast_port_query_expired, (unsigned long)port);
}

void br_multicast_del_port(struct net_bridge_port *port)
{
    del_timer_sync(&port->multicast_router_timer);
}

static void __br_multicast_enable_port(struct net_bridge_port *port)
{
    port->multicast_startup_queries_sent = 0;

    if (try_to_del_timer_sync(&port->multicast_query_timer) >= 0 ||
        del_timer(&port->multicast_query_timer))
        mod_timer(&port->multicast_query_timer, jiffies);
}

void br_multicast_enable_port(struct net_bridge_port *port)
{
    struct net_bridge *br = port->br;

    spin_lock(&br->multicast_lock);
    if (br->multicast_disabled || !netif_running(br->dev))
        goto out;

    __br_multicast_enable_port(port);

out:
    spin_unlock(&br->multicast_lock);
}

void br_multicast_disable_port(struct net_bridge_port *port)
{
    struct net_bridge *br = port->br;
    struct net_bridge_port_group *pg;
    struct hlist_node *p, *n;

    spin_lock(&br->multicast_lock);
    hlist_for_each_entry_safe(pg, p, n, &port->mglist, mglist)
        br_multicast_del_pg(br, pg);

    if (!hlist_unhashed(&port->rlist))
        hlist_del_init_rcu(&port->rlist);
    del_timer(&port->multicast_router_timer);
    del_timer(&port->multicast_query_timer);
    spin_unlock(&br->multicast_lock);
}

static int br_ip4_multicast_igmp3_report(struct net_bridge *br,
                     struct net_bridge_port *port,
                     struct sk_buff *skb)
{
    struct igmpv3_report *ih;
    struct igmpv3_grec *grec;
    int i;
    int len;
    int num;
    int type;
    int err = 0;
    __be32 group;

    if (!pskb_may_pull(skb, sizeof(*ih)))
        return -EINVAL;

    ih = igmpv3_report_hdr(skb);
    num = ntohs(ih->ngrec);
    len = sizeof(*ih);

    for (i = 0; i < num; i++) {
        len += sizeof(*grec);
        if (!pskb_may_pull(skb, len))
            return -EINVAL;

        grec = (void *)(skb->data + len - sizeof(*grec));
        group = grec->grec_mca;
        type = grec->grec_type;

        len += ntohs(grec->grec_nsrcs) * 4;
        if (!pskb_may_pull(skb, len))
            return -EINVAL;

        /* We treat this as an IGMPv2 report for now. */
        switch (type) {
        case IGMPV3_MODE_IS_INCLUDE:
        case IGMPV3_MODE_IS_EXCLUDE:
        case IGMPV3_CHANGE_TO_INCLUDE:
        case IGMPV3_CHANGE_TO_EXCLUDE:
        case IGMPV3_ALLOW_NEW_SOURCES:
        case IGMPV3_BLOCK_OLD_SOURCES:
            break;

        default:
            continue;
        }

        err = br_ip4_multicast_add_group(br, port, group);
        if (err)
            break;
    }

    return err;
}

#if IS_ENABLED(CONFIG_IPV6)
static int br_ip6_multicast_mld2_report(struct net_bridge *br,
                    struct net_bridge_port *port,
                    struct sk_buff *skb)
{
    struct icmp6hdr *icmp6h;
    struct mld2_grec *grec;
    int i;
    int len;
    int num;
    int err = 0;

    if (!pskb_may_pull(skb, sizeof(*icmp6h)))
        return -EINVAL;

    icmp6h = icmp6_hdr(skb);
    num = ntohs(icmp6h->icmp6_dataun.un_data16[1]);
    len = sizeof(*icmp6h);

    for (i = 0; i < num; i++) {
        __be16 *nsrcs, _nsrcs;

        nsrcs = skb_header_pointer(skb,
                       len + offsetof(struct mld2_grec,
                              grec_nsrcs),
                       sizeof(_nsrcs), &_nsrcs);
        if (!nsrcs)
            return -EINVAL;

        if (!pskb_may_pull(skb,
                   len + sizeof(*grec) +
                   sizeof(struct in6_addr) * ntohs(*nsrcs)))
            return -EINVAL;

        grec = (struct mld2_grec *)(skb->data + len);
        len += sizeof(*grec) +
               sizeof(struct in6_addr) * ntohs(*nsrcs);

        /* We treat these as MLDv1 reports for now. */
        switch (grec->grec_type) {
        case MLD2_MODE_IS_INCLUDE:
        case MLD2_MODE_IS_EXCLUDE:
        case MLD2_CHANGE_TO_INCLUDE:
        case MLD2_CHANGE_TO_EXCLUDE:
        case MLD2_ALLOW_NEW_SOURCES:
        case MLD2_BLOCK_OLD_SOURCES:
            break;

        default:
            continue;
        }

        err = br_ip6_multicast_add_group(br, port, &grec->grec_mca);
        if (!err)
            break;
    }

    return err;
}
#endif

/*
 * Add port to rotuer_list
 *  list is maintained ordered by pointer value
 *  and locked by br->multicast_lock and RCU
 */
static void br_multicast_add_router(struct net_bridge *br,
                    struct net_bridge_port *port)
{
    struct net_bridge_port *p;
    struct hlist_node *n, *slot = NULL;

    hlist_for_each_entry(p, n, &br->router_list, rlist) {
        if ((unsigned long) port >= (unsigned long) p)
            break;
        slot = n;
    }

    if (slot)
        hlist_add_after_rcu(slot, &port->rlist);
    else
        hlist_add_head_rcu(&port->rlist, &br->router_list);
}

static void br_multicast_mark_router(struct net_bridge *br,
                     struct net_bridge_port *port)
{
    unsigned long now = jiffies;

    if (!port) {
        if (br->multicast_router == 1)
            mod_timer(&br->multicast_router_timer,
                  now + br->multicast_querier_interval);
        return;
    }

    if (port->multicast_router != 1)
        return;

    if (!hlist_unhashed(&port->rlist))
        goto timer;

    br_multicast_add_router(br, port);

timer:
    mod_timer(&port->multicast_router_timer,
          now + br->multicast_querier_interval);
}

static void br_multicast_query_received(struct net_bridge *br,
                    struct net_bridge_port *port,
                    int saddr)
{
    if (saddr)
        mod_timer(&br->multicast_querier_timer,
              jiffies + br->multicast_querier_interval);
    else if (timer_pending(&br->multicast_querier_timer))
        return;

    br_multicast_mark_router(br, port);
}

static int br_ip4_multicast_query(struct net_bridge *br,
                  struct net_bridge_port *port,
                  struct sk_buff *skb)
{
    const struct iphdr *iph = ip_hdr(skb);
    struct igmphdr *ih = igmp_hdr(skb);
    struct net_bridge_mdb_entry *mp;
    struct igmpv3_query *ih3;
    struct net_bridge_port_group *p;
    struct net_bridge_port_group __rcu **pp;
    unsigned long max_delay;
    unsigned long now = jiffies;
    __be32 group;
    int err = 0;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev) ||
        (port && port->state == BR_STATE_DISABLED))
        goto out;

    br_multicast_query_received(br, port, !!iph->saddr);

    group = ih->group;

    if (skb->len == sizeof(*ih)) {
        max_delay = ih->code * (HZ / IGMP_TIMER_SCALE);

        if (!max_delay) {
            max_delay = 10 * HZ;
            group = 0;
        }
    } else {
        if (!pskb_may_pull(skb, sizeof(struct igmpv3_query))) {
            err = -EINVAL;
            goto out;
        }

        ih3 = igmpv3_query_hdr(skb);
        if (ih3->nsrcs)
            goto out;

        max_delay = ih3->code ?
                IGMPV3_MRC(ih3->code) * (HZ / IGMP_TIMER_SCALE) : 1;
    }

    if (!group)
        goto out;

    mp = br_mdb_ip4_get(mlock_dereference(br->mdb, br), group);
    if (!mp)
        goto out;

    max_delay *= br->multicast_last_member_count;

    if (mp->mglist &&
        (timer_pending(&mp->timer) ?
         time_after(mp->timer.expires, now + max_delay) :
         try_to_del_timer_sync(&mp->timer) >= 0))
        mod_timer(&mp->timer, now + max_delay);

    for (pp = &mp->ports;
         (p = mlock_dereference(*pp, br)) != NULL;
         pp = &p->next) {
        if (timer_pending(&p->timer) ?
            time_after(p->timer.expires, now + max_delay) :
            try_to_del_timer_sync(&p->timer) >= 0)
            mod_timer(&p->timer, now + max_delay);
    }

out:
    spin_unlock(&br->multicast_lock);
    return err;
}

#if IS_ENABLED(CONFIG_IPV6)
static int br_ip6_multicast_query(struct net_bridge *br,
                  struct net_bridge_port *port,
                  struct sk_buff *skb)
{
    const struct ipv6hdr *ip6h = ipv6_hdr(skb);
    struct mld_msg *mld = (struct mld_msg *) icmp6_hdr(skb);
    struct net_bridge_mdb_entry *mp;
    struct mld2_query *mld2q;
    struct net_bridge_port_group *p;
    struct net_bridge_port_group __rcu **pp;
    unsigned long max_delay;
    unsigned long now = jiffies;
    const struct in6_addr *group = NULL;
    int err = 0;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev) ||
        (port && port->state == BR_STATE_DISABLED))
        goto out;

    br_multicast_query_received(br, port, !ipv6_addr_any(&ip6h->saddr));

    if (skb->len == sizeof(*mld)) {
        if (!pskb_may_pull(skb, sizeof(*mld))) {
            err = -EINVAL;
            goto out;
        }
        mld = (struct mld_msg *) icmp6_hdr(skb);
        max_delay = msecs_to_jiffies(ntohs(mld->mld_maxdelay));
        if (max_delay)
            group = &mld->mld_mca;
    } else if (skb->len >= sizeof(*mld2q)) {
        if (!pskb_may_pull(skb, sizeof(*mld2q))) {
            err = -EINVAL;
            goto out;
        }
        mld2q = (struct mld2_query *)icmp6_hdr(skb);
        if (!mld2q->mld2q_nsrcs)
            group = &mld2q->mld2q_mca;
        max_delay = mld2q->mld2q_mrc ? MLDV2_MRC(mld2q->mld2q_mrc) : 1;
    }

    if (!group)
        goto out;

    mp = br_mdb_ip6_get(mlock_dereference(br->mdb, br), group);
    if (!mp)
        goto out;

    max_delay *= br->multicast_last_member_count;
    if (mp->mglist &&
        (timer_pending(&mp->timer) ?
         time_after(mp->timer.expires, now + max_delay) :
         try_to_del_timer_sync(&mp->timer) >= 0))
        mod_timer(&mp->timer, now + max_delay);

    for (pp = &mp->ports;
         (p = mlock_dereference(*pp, br)) != NULL;
         pp = &p->next) {
        if (timer_pending(&p->timer) ?
            time_after(p->timer.expires, now + max_delay) :
            try_to_del_timer_sync(&p->timer) >= 0)
            mod_timer(&p->timer, now + max_delay);
    }

out:
    spin_unlock(&br->multicast_lock);
    return err;
}
#endif

static void br_multicast_leave_group(struct net_bridge *br,
                     struct net_bridge_port *port,
                     struct br_ip *group)
{
    struct net_bridge_mdb_htable *mdb;
    struct net_bridge_mdb_entry *mp;
    struct net_bridge_port_group *p;
    unsigned long now;
    unsigned long time;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev) ||
        (port && port->state == BR_STATE_DISABLED) ||
        timer_pending(&br->multicast_querier_timer))
        goto out;

    mdb = mlock_dereference(br->mdb, br);
    mp = br_mdb_ip_get(mdb, group);
    if (!mp)
        goto out;

    now = jiffies;
    time = now + br->multicast_last_member_count *
             br->multicast_last_member_interval;

    if (!port) {
        if (mp->mglist &&
            (timer_pending(&mp->timer) ?
             time_after(mp->timer.expires, time) :
             try_to_del_timer_sync(&mp->timer) >= 0)) {
            mod_timer(&mp->timer, time);
        }

        goto out;
    }

    for (p = mlock_dereference(mp->ports, br);
         p != NULL;
         p = mlock_dereference(p->next, br)) {
        if (p->port != port)
            continue;

        if (!hlist_unhashed(&p->mglist) &&
            (timer_pending(&p->timer) ?
             time_after(p->timer.expires, time) :
             try_to_del_timer_sync(&p->timer) >= 0)) {
            mod_timer(&p->timer, time);
        }

        break;
    }

out:
    spin_unlock(&br->multicast_lock);
}

static void br_ip4_multicast_leave_group(struct net_bridge *br,
                     struct net_bridge_port *port,
                     __be32 group)
{
    struct br_ip br_group;

    if (ipv4_is_local_multicast(group))
        return;

    br_group.u.ip4 = group;
    br_group.proto = htons(ETH_P_IP);

    br_multicast_leave_group(br, port, &br_group);
}

#if IS_ENABLED(CONFIG_IPV6)
static void br_ip6_multicast_leave_group(struct net_bridge *br,
                     struct net_bridge_port *port,
                     const struct in6_addr *group)
{
    struct br_ip br_group;

    if (!ipv6_is_transient_multicast(group))
        return;

    br_group.u.ip6 = *group;
    br_group.proto = htons(ETH_P_IPV6);

    br_multicast_leave_group(br, port, &br_group);
}
#endif

static int br_multicast_ipv4_rcv(struct net_bridge *br,
                 struct net_bridge_port *port,
                 struct sk_buff *skb)
{
    struct sk_buff *skb2 = skb;
    const struct iphdr *iph;
    struct igmphdr *ih;
    unsigned int len;
    unsigned int offset;
    int err;

    /* We treat OOM as packet loss for now. */
    if (!pskb_may_pull(skb, sizeof(*iph)))
        return -EINVAL;

    iph = ip_hdr(skb);

    if (iph->ihl < 5 || iph->version != 4)
        return -EINVAL;

    if (!pskb_may_pull(skb, ip_hdrlen(skb)))
        return -EINVAL;

    iph = ip_hdr(skb);

    if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
        return -EINVAL;

    if (iph->protocol != IPPROTO_IGMP) {
        if ((iph->daddr & IGMP_LOCAL_GROUP_MASK) != IGMP_LOCAL_GROUP)
            BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
        return 0;
    }

    len = ntohs(iph->tot_len);
    if (skb->len < len || len < ip_hdrlen(skb))
        return -EINVAL;

    if (skb->len > len) {
        skb2 = skb_clone(skb, GFP_ATOMIC);
        if (!skb2)
            return -ENOMEM;

        err = pskb_trim_rcsum(skb2, len);
        if (err)
            goto err_out;
    }

    len -= ip_hdrlen(skb2);
    offset = skb_network_offset(skb2) + ip_hdrlen(skb2);
    __skb_pull(skb2, offset);
    skb_reset_transport_header(skb2);

    err = -EINVAL;
    if (!pskb_may_pull(skb2, sizeof(*ih)))
        goto out;

    switch (skb2->ip_summed) {
    case CHECKSUM_COMPLETE:
        if (!csum_fold(skb2->csum))
            break;
        /* fall through */
    case CHECKSUM_NONE:
        skb2->csum = 0;
        if (skb_checksum_complete(skb2))
            goto out;
    }

    err = 0;

    BR_INPUT_SKB_CB(skb)->igmp = 1;
    ih = igmp_hdr(skb2);

    switch (ih->type) {
    case IGMP_HOST_MEMBERSHIP_REPORT:
    case IGMPV2_HOST_MEMBERSHIP_REPORT:
        BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
        err = br_ip4_multicast_add_group(br, port, ih->group);
        break;
    case IGMPV3_HOST_MEMBERSHIP_REPORT:
        err = br_ip4_multicast_igmp3_report(br, port, skb2);
        break;
    case IGMP_HOST_MEMBERSHIP_QUERY:
        err = br_ip4_multicast_query(br, port, skb2);
        break;
    case IGMP_HOST_LEAVE_MESSAGE:
        br_ip4_multicast_leave_group(br, port, ih->group);
        break;
    }

out:
    __skb_push(skb2, offset);
err_out:
    if (skb2 != skb)
        kfree_skb(skb2);
    return err;
}

#if IS_ENABLED(CONFIG_IPV6)
static int br_multicast_ipv6_rcv(struct net_bridge *br,
                 struct net_bridge_port *port,
                 struct sk_buff *skb)
{
    struct sk_buff *skb2;
    const struct ipv6hdr *ip6h;
    u8 icmp6_type;
    u8 nexthdr;
    __be16 frag_off;
    unsigned int len;
    int offset;
    int err;

    if (!pskb_may_pull(skb, sizeof(*ip6h)))
        return -EINVAL;

    ip6h = ipv6_hdr(skb);

    /*
     * We're interested in MLD messages only.
     *  - Version is 6
     *  - MLD has always Router Alert hop-by-hop option
     *  - But we do not support jumbrograms.
     */
    if (ip6h->version != 6 ||
        ip6h->nexthdr != IPPROTO_HOPOPTS ||
        ip6h->payload_len == 0)
        return 0;

    len = ntohs(ip6h->payload_len) + sizeof(*ip6h);
    if (skb->len < len)
        return -EINVAL;

    nexthdr = ip6h->nexthdr;
    offset = ipv6_skip_exthdr(skb, sizeof(*ip6h), &nexthdr, &frag_off);

    if (offset < 0 || nexthdr != IPPROTO_ICMPV6)
        return 0;

    /* Okay, we found ICMPv6 header */
    skb2 = skb_clone(skb, GFP_ATOMIC);
    if (!skb2)
        return -ENOMEM;

    err = -EINVAL;
    if (!pskb_may_pull(skb2, offset + sizeof(struct icmp6hdr)))
        goto out;

    len -= offset - skb_network_offset(skb2);

    __skb_pull(skb2, offset);
    skb_reset_transport_header(skb2);
    skb_postpull_rcsum(skb2, skb_network_header(skb2),
               skb_network_header_len(skb2));

    icmp6_type = icmp6_hdr(skb2)->icmp6_type;

    switch (icmp6_type) {
    case ICMPV6_MGM_QUERY:
    case ICMPV6_MGM_REPORT:
    case ICMPV6_MGM_REDUCTION:
    case ICMPV6_MLD2_REPORT:
        break;
    default:
        err = 0;
        goto out;
    }

    /* Okay, we found MLD message. Check further. */
    if (skb2->len > len) {
        err = pskb_trim_rcsum(skb2, len);
        if (err)
            goto out;
        err = -EINVAL;
    }

    ip6h = ipv6_hdr(skb2);

    switch (skb2->ip_summed) {
    case CHECKSUM_COMPLETE:
        if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, skb2->len,
                    IPPROTO_ICMPV6, skb2->csum))
            break;
        /*FALLTHROUGH*/
    case CHECKSUM_NONE:
        skb2->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr,
                            &ip6h->daddr,
                            skb2->len,
                            IPPROTO_ICMPV6, 0));
        if (__skb_checksum_complete(skb2))
            goto out;
    }

    err = 0;

    BR_INPUT_SKB_CB(skb)->igmp = 1;

    switch (icmp6_type) {
    case ICMPV6_MGM_REPORT:
        {
        struct mld_msg *mld;
        if (!pskb_may_pull(skb2, sizeof(*mld))) {
            err = -EINVAL;
            goto out;
        }
        mld = (struct mld_msg *)skb_transport_header(skb2);
        BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
        err = br_ip6_multicast_add_group(br, port, &mld->mld_mca);
        break;
        }
    case ICMPV6_MLD2_REPORT:
        err = br_ip6_multicast_mld2_report(br, port, skb2);
        break;
    case ICMPV6_MGM_QUERY:
        err = br_ip6_multicast_query(br, port, skb2);
        break;
    case ICMPV6_MGM_REDUCTION:
        {
        struct mld_msg *mld;
        if (!pskb_may_pull(skb2, sizeof(*mld))) {
            err = -EINVAL;
            goto out;
        }
        mld = (struct mld_msg *)skb_transport_header(skb2);
        br_ip6_multicast_leave_group(br, port, &mld->mld_mca);
        }
    }

out:
    kfree_skb(skb2);
    return err;
}
#endif

int br_multicast_rcv(struct net_bridge *br, struct net_bridge_port *port,
             struct sk_buff *skb)
{
    BR_INPUT_SKB_CB(skb)->igmp = 0;
    BR_INPUT_SKB_CB(skb)->mrouters_only = 0;

    if (br->multicast_disabled)
        return 0;

    switch (skb->protocol) {
    case htons(ETH_P_IP):
        return br_multicast_ipv4_rcv(br, port, skb);
#if IS_ENABLED(CONFIG_IPV6)
    case htons(ETH_P_IPV6):
        return br_multicast_ipv6_rcv(br, port, skb);
#endif
    }

    return 0;
}

static void br_multicast_query_expired(unsigned long data)
{
    struct net_bridge *br = (void *)data;

    spin_lock(&br->multicast_lock);
    if (br->multicast_startup_queries_sent <
        br->multicast_startup_query_count)
        br->multicast_startup_queries_sent++;

    br_multicast_send_query(br, NULL, br->multicast_startup_queries_sent);

    spin_unlock(&br->multicast_lock);
}

void br_multicast_init(struct net_bridge *br)
{
    br->hash_elasticity = 4;
    br->hash_max = 512;

    br->multicast_router = 1;
    br->multicast_querier = 0;
    br->multicast_last_member_count = 2;
    br->multicast_startup_query_count = 2;

    br->multicast_last_member_interval = HZ;
    br->multicast_query_response_interval = 10 * HZ;
    br->multicast_startup_query_interval = 125 * HZ / 4;
    br->multicast_query_interval = 125 * HZ;
    br->multicast_querier_interval = 255 * HZ;
    br->multicast_membership_interval = 260 * HZ;

    spin_lock_init(&br->multicast_lock);
    setup_timer(&br->multicast_router_timer,
            br_multicast_local_router_expired, 0);
    setup_timer(&br->multicast_querier_timer,
            br_multicast_querier_expired, (unsigned long)br);
    setup_timer(&br->multicast_query_timer, br_multicast_query_expired,
            (unsigned long)br);
}

void br_multicast_open(struct net_bridge *br)
{
    br->multicast_startup_queries_sent = 0;

    if (br->multicast_disabled)
        return;

    mod_timer(&br->multicast_query_timer, jiffies);
}

void br_multicast_stop(struct net_bridge *br)
{
    struct net_bridge_mdb_htable *mdb;
    struct net_bridge_mdb_entry *mp;
    struct hlist_node *p, *n;
    u32 ver;
    int i;

    del_timer_sync(&br->multicast_router_timer);
    del_timer_sync(&br->multicast_querier_timer);
    del_timer_sync(&br->multicast_query_timer);

    spin_lock_bh(&br->multicast_lock);
    mdb = mlock_dereference(br->mdb, br);
    if (!mdb)
        goto out;

    br->mdb = NULL;

    ver = mdb->ver;
    for (i = 0; i < mdb->max; i++) {
        hlist_for_each_entry_safe(mp, p, n, &mdb->mhash[i],
                      hlist[ver]) {
            del_timer(&mp->timer);
            call_rcu_bh(&mp->rcu, br_multicast_free_group);
        }
    }

    if (mdb->old) {
        spin_unlock_bh(&br->multicast_lock);
        rcu_barrier_bh();
        spin_lock_bh(&br->multicast_lock);
        WARN_ON(mdb->old);
    }

    mdb->old = mdb;
    call_rcu_bh(&mdb->rcu, br_mdb_free);

out:
    spin_unlock_bh(&br->multicast_lock);
}

int br_multicast_set_router(struct net_bridge *br, unsigned long val)
{
    int err = -ENOENT;

    spin_lock_bh(&br->multicast_lock);
    if (!netif_running(br->dev))
        goto unlock;

    switch (val) {
    case 0:
    case 2:
        del_timer(&br->multicast_router_timer);
        /* fall through */
    case 1:
        br->multicast_router = val;
        err = 0;
        break;

    default:
        err = -EINVAL;
        break;
    }

unlock:
    spin_unlock_bh(&br->multicast_lock);

    return err;
}

int br_multicast_set_port_router(struct net_bridge_port *p, unsigned long val)
{
    struct net_bridge *br = p->br;
    int err = -ENOENT;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev) || p->state == BR_STATE_DISABLED)
        goto unlock;

    switch (val) {
    case 0:
    case 1:
    case 2:
        p->multicast_router = val;
        err = 0;

        if (val < 2 && !hlist_unhashed(&p->rlist))
            hlist_del_init_rcu(&p->rlist);

        if (val == 1)
            break;

        del_timer(&p->multicast_router_timer);

        if (val == 0)
            break;

        br_multicast_add_router(br, p);
        break;

    default:
        err = -EINVAL;
        break;
    }

unlock:
    spin_unlock(&br->multicast_lock);

    return err;
}

static void br_multicast_start_querier(struct net_bridge *br)
{
    struct net_bridge_port *port;

    br_multicast_open(br);

    list_for_each_entry(port, &br->port_list, list) {
        if (port->state == BR_STATE_DISABLED ||
            port->state == BR_STATE_BLOCKING)
            continue;

        __br_multicast_enable_port(port);
    }
}

int br_multicast_toggle(struct net_bridge *br, unsigned long val)
{
    int err = 0;
    struct net_bridge_mdb_htable *mdb;

    spin_lock_bh(&br->multicast_lock);
    if (br->multicast_disabled == !val)
        goto unlock;

    br->multicast_disabled = !val;
    if (br->multicast_disabled)
        goto unlock;

    if (!netif_running(br->dev))
        goto unlock;

    mdb = mlock_dereference(br->mdb, br);
    if (mdb) {
        if (mdb->old) {
            err = -EEXIST;
rollback:
            br->multicast_disabled = !!val;
            goto unlock;
        }

        err = br_mdb_rehash(&br->mdb, mdb->max,
                    br->hash_elasticity);
        if (err)
            goto rollback;
    }

    br_multicast_start_querier(br);

unlock:
    spin_unlock_bh(&br->multicast_lock);

    return err;
}

int br_multicast_set_querier(struct net_bridge *br, unsigned long val)
{
    val = !!val;

    spin_lock_bh(&br->multicast_lock);
    if (br->multicast_querier == val)
        goto unlock;

    br->multicast_querier = val;
    if (val)
        br_multicast_start_querier(br);

unlock:
    spin_unlock_bh(&br->multicast_lock);

    return 0;
}

int br_multicast_set_hash_max(struct net_bridge *br, unsigned long val)
{
    int err = -ENOENT;
    u32 old;
    struct net_bridge_mdb_htable *mdb;

    spin_lock(&br->multicast_lock);
    if (!netif_running(br->dev))
        goto unlock;

    err = -EINVAL;
    if (!is_power_of_2(val))
        goto unlock;

    mdb = mlock_dereference(br->mdb, br);
    if (mdb && val < mdb->size)
        goto unlock;

    err = 0;

    old = br->hash_max;
    br->hash_max = val;

    if (mdb) {
        if (mdb->old) {
            err = -EEXIST;
rollback:
            br->hash_max = old;
            goto unlock;
        }

        err = br_mdb_rehash(&br->mdb, br->hash_max,
                    br->hash_elasticity);
        if (err)
            goto rollback;
    }

unlock:
    spin_unlock(&br->multicast_lock);

    return err;
}