/*
 *      Multicast support for IPv6
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *
 *      Based on linux/ipv4/igmp.c and linux/ipv4/ip_sockglue.c
 *
 *      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.
 */

/* Changes:
 *
 *      yoshfuji        : fix format of router-alert option
 *      YOSHIFUJI Hideaki @USAGI:
 *              Fixed source address for MLD message based on
 *              <draft-ietf-magma-mld-source-05.txt>.
 *      YOSHIFUJI Hideaki @USAGI:
 *              - Ignore Queries for invalid addresses.
 *              - MLD for link-local addresses.
 *      David L Stevens <dlstevens@us.ibm.com>:
 *              - MLDv2 support
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/jiffies.h>
#include <linux/times.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/route.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/pkt_sched.h>
#include <net/mld.h>

#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>

#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/snmp.h>

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/if_inet6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/inet_common.h>

#include <net/ip6_checksum.h>

/* Ensure that we have struct in6_addr aligned on 32bit word. */
static int __mld2_query_bugs[] __attribute__((__unused__)) = {
        BUILD_BUG_ON_ZERO(offsetof(struct mld2_query, mld2q_srcs) % 4),
        BUILD_BUG_ON_ZERO(offsetof(struct mld2_report, mld2r_grec) % 4),
        BUILD_BUG_ON_ZERO(offsetof(struct mld2_grec, grec_mca) % 4)
};

static struct in6_addr mld2_all_mcr = MLD2_ALL_MCR_INIT;

static void igmp6_join_group(struct ifmcaddr6 *ma);
static void igmp6_leave_group(struct ifmcaddr6 *ma);
static void igmp6_timer_handler(struct timer_list *t);

static void mld_gq_timer_expire(struct timer_list *t);
static void mld_ifc_timer_expire(struct timer_list *t);
static void mld_ifc_event(struct inet6_dev *idev);
static void mld_add_delrec(struct inet6_dev *idev, struct ifmcaddr6 *pmc);
static void mld_del_delrec(struct inet6_dev *idev, struct ifmcaddr6 *pmc);
static void mld_clear_delrec(struct inet6_dev *idev);
static bool mld_in_v1_mode(const struct inet6_dev *idev);
static int sf_setstate(struct ifmcaddr6 *pmc);
static void sf_markstate(struct ifmcaddr6 *pmc);
static void ip6_mc_clear_src(struct ifmcaddr6 *pmc);
static int ip6_mc_del_src(struct inet6_dev *idev, const struct in6_addr *pmca,
                          int sfmode, int sfcount, const struct in6_addr *psfsrc,
                          int delta);
static int ip6_mc_add_src(struct inet6_dev *idev, const struct in6_addr *pmca,
                          int sfmode, int sfcount, const struct in6_addr *psfsrc,
                          int delta);
static int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
                            struct inet6_dev *idev);
static int __ipv6_dev_mc_inc(struct net_device *dev,
                             const struct in6_addr *addr, unsigned int mode);

#define MLD_QRV_DEFAULT         2
/* RFC3810, 9.2. Query Interval */
#define MLD_QI_DEFAULT          (125 * HZ)
/* RFC3810, 9.3. Query Response Interval */
#define MLD_QRI_DEFAULT         (10 * HZ)

/* RFC3810, 8.1 Query Version Distinctions */
#define MLD_V1_QUERY_LEN        24
#define MLD_V2_QUERY_LEN_MIN    28

#define IPV6_MLD_MAX_MSF        64

int sysctl_mld_max_msf __read_mostly = IPV6_MLD_MAX_MSF;
int sysctl_mld_qrv __read_mostly = MLD_QRV_DEFAULT;

/*
 *      socket join on multicast group
 */

#define for_each_pmc_rcu(np, pmc)                               \
        for (pmc = rcu_dereference(np->ipv6_mc_list);           \
             pmc != NULL;                                       \
             pmc = rcu_dereference(pmc->next))

static int unsolicited_report_interval(struct inet6_dev *idev)
{
        int iv;

        if (mld_in_v1_mode(idev))
                iv = idev->cnf.mldv1_unsolicited_report_interval;
        else
                iv = idev->cnf.mldv2_unsolicited_report_interval;

        return iv > 0 ? iv : 1;
}

static int __ipv6_sock_mc_join(struct sock *sk, int ifindex,
                               const struct in6_addr *addr, unsigned int mode)
{
        struct net_device *dev = NULL;
        struct ipv6_mc_socklist *mc_lst;
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct net *net = sock_net(sk);
        int err;

        ASSERT_RTNL();

        if (!ipv6_addr_is_multicast(addr))
                return -EINVAL;

        rcu_read_lock();
        for_each_pmc_rcu(np, mc_lst) {
                if ((ifindex == 0 || mc_lst->ifindex == ifindex) &&
                    ipv6_addr_equal(&mc_lst->addr, addr)) {
                        rcu_read_unlock();
                        return -EADDRINUSE;
                }
        }
        rcu_read_unlock();

        mc_lst = sock_kmalloc(sk, sizeof(struct ipv6_mc_socklist), GFP_KERNEL);

        if (!mc_lst)
                return -ENOMEM;

        mc_lst->next = NULL;
        mc_lst->addr = *addr;

        if (ifindex == 0) {
                struct rt6_info *rt;
                rt = rt6_lookup(net, addr, NULL, 0, NULL, 0);
                if (rt) {
                        dev = rt->dst.dev;
                        ip6_rt_put(rt);
                }
        } else
                dev = __dev_get_by_index(net, ifindex);

        if (!dev) {
                sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
                return -ENODEV;
        }

        mc_lst->ifindex = dev->ifindex;
        mc_lst->sfmode = mode;
        rwlock_init(&mc_lst->sflock);
        mc_lst->sflist = NULL;

        /*
         *      now add/increase the group membership on the device
         */

        err = __ipv6_dev_mc_inc(dev, addr, mode);

        if (err) {
                sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
                return err;
        }

        mc_lst->next = np->ipv6_mc_list;
        rcu_assign_pointer(np->ipv6_mc_list, mc_lst);

        return 0;
}

int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
{
        return __ipv6_sock_mc_join(sk, ifindex, addr, MCAST_EXCLUDE);
}
EXPORT_SYMBOL(ipv6_sock_mc_join);

int ipv6_sock_mc_join_ssm(struct sock *sk, int ifindex,
                          const struct in6_addr *addr, unsigned int mode)
{
        return __ipv6_sock_mc_join(sk, ifindex, addr, mode);
}

/*
 *      socket leave on multicast group
 */
int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct ipv6_mc_socklist *mc_lst;
        struct ipv6_mc_socklist __rcu **lnk;
        struct net *net = sock_net(sk);

        ASSERT_RTNL();

        if (!ipv6_addr_is_multicast(addr))
                return -EINVAL;

        for (lnk = &np->ipv6_mc_list;
             (mc_lst = rtnl_dereference(*lnk)) != NULL;
              lnk = &mc_lst->next) {
                if ((ifindex == 0 || mc_lst->ifindex == ifindex) &&
                    ipv6_addr_equal(&mc_lst->addr, addr)) {
                        struct net_device *dev;

                        *lnk = mc_lst->next;

                        dev = __dev_get_by_index(net, mc_lst->ifindex);
                        if (dev) {
                                struct inet6_dev *idev = __in6_dev_get(dev);

                                (void) ip6_mc_leave_src(sk, mc_lst, idev);
                                if (idev)
                                        __ipv6_dev_mc_dec(idev, &mc_lst->addr);
                        } else
                                (void) ip6_mc_leave_src(sk, mc_lst, NULL);

                        atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);
                        kfree_rcu(mc_lst, rcu);
                        return 0;
                }
        }

        return -EADDRNOTAVAIL;
}
EXPORT_SYMBOL(ipv6_sock_mc_drop);

/* called with rcu_read_lock() */
static struct inet6_dev *ip6_mc_find_dev_rcu(struct net *net,
                                             const struct in6_addr *group,
                                             int ifindex)
{
        struct net_device *dev = NULL;
        struct inet6_dev *idev = NULL;

        if (ifindex == 0) {
                struct rt6_info *rt = rt6_lookup(net, group, NULL, 0, NULL, 0);

                if (rt) {
                        dev = rt->dst.dev;
                        ip6_rt_put(rt);
                }
        } else
                dev = dev_get_by_index_rcu(net, ifindex);

        if (!dev)
                return NULL;
        idev = __in6_dev_get(dev);
        if (!idev)
                return NULL;
        read_lock_bh(&idev->lock);
        if (idev->dead) {
                read_unlock_bh(&idev->lock);
                return NULL;
        }
        return idev;
}

void __ipv6_sock_mc_close(struct sock *sk)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct ipv6_mc_socklist *mc_lst;
        struct net *net = sock_net(sk);

        ASSERT_RTNL();

        while ((mc_lst = rtnl_dereference(np->ipv6_mc_list)) != NULL) {
                struct net_device *dev;

                np->ipv6_mc_list = mc_lst->next;

                dev = __dev_get_by_index(net, mc_lst->ifindex);
                if (dev) {
                        struct inet6_dev *idev = __in6_dev_get(dev);

                        (void) ip6_mc_leave_src(sk, mc_lst, idev);
                        if (idev)
                                __ipv6_dev_mc_dec(idev, &mc_lst->addr);
                } else
                        (void) ip6_mc_leave_src(sk, mc_lst, NULL);

                atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);
                kfree_rcu(mc_lst, rcu);
        }
}

void ipv6_sock_mc_close(struct sock *sk)
{
        struct ipv6_pinfo *np = inet6_sk(sk);

        if (!rcu_access_pointer(np->ipv6_mc_list))
                return;
        rtnl_lock();
        __ipv6_sock_mc_close(sk);
        rtnl_unlock();
}

int ip6_mc_source(int add, int omode, struct sock *sk,
        struct group_source_req *pgsr)
{
        struct in6_addr *source, *group;
        struct ipv6_mc_socklist *pmc;
        struct inet6_dev *idev;
        struct ipv6_pinfo *inet6 = inet6_sk(sk);
        struct ip6_sf_socklist *psl;
        struct net *net = sock_net(sk);
        int i, j, rv;
        int leavegroup = 0;
        int pmclocked = 0;
        int err;

        source = &((struct sockaddr_in6 *)&pgsr->gsr_source)->sin6_addr;
        group = &((struct sockaddr_in6 *)&pgsr->gsr_group)->sin6_addr;

        if (!ipv6_addr_is_multicast(group))
                return -EINVAL;

        rcu_read_lock();
        idev = ip6_mc_find_dev_rcu(net, group, pgsr->gsr_interface);
        if (!idev) {
                rcu_read_unlock();
                return -ENODEV;
        }

        err = -EADDRNOTAVAIL;

        for_each_pmc_rcu(inet6, pmc) {
                if (pgsr->gsr_interface && pmc->ifindex != pgsr->gsr_interface)
                        continue;
                if (ipv6_addr_equal(&pmc->addr, group))
                        break;
        }
        if (!pmc) {             /* must have a prior join */
                err = -EINVAL;
                goto done;
        }
        /* if a source filter was set, must be the same mode as before */
        if (pmc->sflist) {
                if (pmc->sfmode != omode) {
                        err = -EINVAL;
                        goto done;
                }
        } else if (pmc->sfmode != omode) {
                /* allow mode switches for empty-set filters */
                ip6_mc_add_src(idev, group, omode, 0, NULL, 0);
                ip6_mc_del_src(idev, group, pmc->sfmode, 0, NULL, 0);
                pmc->sfmode = omode;
        }

        write_lock(&pmc->sflock);
        pmclocked = 1;

        psl = pmc->sflist;
        if (!add) {
                if (!psl)
                        goto done;      /* err = -EADDRNOTAVAIL */
                rv = !0;
                for (i = 0; i < psl->sl_count; i++) {
                        rv = !ipv6_addr_equal(&psl->sl_addr[i], source);
                        if (rv == 0)
                                break;
                }
                if (rv)         /* source not found */
                        goto done;      /* err = -EADDRNOTAVAIL */

                /* special case - (INCLUDE, empty) == LEAVE_GROUP */
                if (psl->sl_count == 1 && omode == MCAST_INCLUDE) {
                        leavegroup = 1;
                        goto done;
                }

                /* update the interface filter */
                ip6_mc_del_src(idev, group, omode, 1, source, 1);

                for (j = i+1; j < psl->sl_count; j++)
                        psl->sl_addr[j-1] = psl->sl_addr[j];
                psl->sl_count--;
                err = 0;
                goto done;
        }
        /* else, add a new source to the filter */

        if (psl && psl->sl_count >= sysctl_mld_max_msf) {
                err = -ENOBUFS;
                goto done;
        }
        if (!psl || psl->sl_count == psl->sl_max) {
                struct ip6_sf_socklist *newpsl;
                int count = IP6_SFBLOCK;

                if (psl)
                        count += psl->sl_max;
                newpsl = sock_kmalloc(sk, IP6_SFLSIZE(count), GFP_ATOMIC);
                if (!newpsl) {
                        err = -ENOBUFS;
                        goto done;
                }
                newpsl->sl_max = count;
                newpsl->sl_count = count - IP6_SFBLOCK;
                if (psl) {
                        for (i = 0; i < psl->sl_count; i++)
                                newpsl->sl_addr[i] = psl->sl_addr[i];
                        sock_kfree_s(sk, psl, IP6_SFLSIZE(psl->sl_max));
                }
                pmc->sflist = psl = newpsl;
        }
        rv = 1; /* > 0 for insert logic below if sl_count is 0 */
        for (i = 0; i < psl->sl_count; i++) {
                rv = !ipv6_addr_equal(&psl->sl_addr[i], source);
                if (rv == 0) /* There is an error in the address. */
                        goto done;
        }
        for (j = psl->sl_count-1; j >= i; j--)
                psl->sl_addr[j+1] = psl->sl_addr[j];
        psl->sl_addr[i] = *source;
        psl->sl_count++;
        err = 0;
        /* update the interface list */
        ip6_mc_add_src(idev, group, omode, 1, source, 1);
done:
        if (pmclocked)
                write_unlock(&pmc->sflock);
        read_unlock_bh(&idev->lock);
        rcu_read_unlock();
        if (leavegroup)
                err = ipv6_sock_mc_drop(sk, pgsr->gsr_interface, group);
        return err;
}

int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf)
{
        const struct in6_addr *group;
        struct ipv6_mc_socklist *pmc;
        struct inet6_dev *idev;
        struct ipv6_pinfo *inet6 = inet6_sk(sk);
        struct ip6_sf_socklist *newpsl, *psl;
        struct net *net = sock_net(sk);
        int leavegroup = 0;
        int i, err;

        group = &((struct sockaddr_in6 *)&gsf->gf_group)->sin6_addr;

        if (!ipv6_addr_is_multicast(group))
                return -EINVAL;
        if (gsf->gf_fmode != MCAST_INCLUDE &&
            gsf->gf_fmode != MCAST_EXCLUDE)
                return -EINVAL;

        rcu_read_lock();
        idev = ip6_mc_find_dev_rcu(net, group, gsf->gf_interface);

        if (!idev) {
                rcu_read_unlock();
                return -ENODEV;
        }

        err = 0;

        if (gsf->gf_fmode == MCAST_INCLUDE && gsf->gf_numsrc == 0) {
                leavegroup = 1;
                goto done;
        }

        for_each_pmc_rcu(inet6, pmc) {
                if (pmc->ifindex != gsf->gf_interface)
                        continue;
                if (ipv6_addr_equal(&pmc->addr, group))
                        break;
        }
        if (!pmc) {             /* must have a prior join */
                err = -EINVAL;
                goto done;
        }
        if (gsf->gf_numsrc) {
                newpsl = sock_kmalloc(sk, IP6_SFLSIZE(gsf->gf_numsrc),
                                                          GFP_ATOMIC);
                if (!newpsl) {
                        err = -ENOBUFS;
                        goto done;
                }
                newpsl->sl_max = newpsl->sl_count = gsf->gf_numsrc;
                for (i = 0; i < newpsl->sl_count; ++i) {
                        struct sockaddr_in6 *psin6;

                        psin6 = (struct sockaddr_in6 *)&gsf->gf_slist[i];
                        newpsl->sl_addr[i] = psin6->sin6_addr;
                }
                err = ip6_mc_add_src(idev, group, gsf->gf_fmode,
                        newpsl->sl_count, newpsl->sl_addr, 0);
                if (err) {
                        sock_kfree_s(sk, newpsl, IP6_SFLSIZE(newpsl->sl_max));
                        goto done;
                }
        } else {
                newpsl = NULL;
                (void) ip6_mc_add_src(idev, group, gsf->gf_fmode, 0, NULL, 0);
        }

        write_lock(&pmc->sflock);
        psl = pmc->sflist;
        if (psl) {
                (void) ip6_mc_del_src(idev, group, pmc->sfmode,
                        psl->sl_count, psl->sl_addr, 0);
                sock_kfree_s(sk, psl, IP6_SFLSIZE(psl->sl_max));
        } else
                (void) ip6_mc_del_src(idev, group, pmc->sfmode, 0, NULL, 0);
        pmc->sflist = newpsl;
        pmc->sfmode = gsf->gf_fmode;
        write_unlock(&pmc->sflock);
        err = 0;
done:
        read_unlock_bh(&idev->lock);
        rcu_read_unlock();
        if (leavegroup)
                err = ipv6_sock_mc_drop(sk, gsf->gf_interface, group);
        return err;
}

int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
        struct group_filter __user *optval, int __user *optlen)
{
        int err, i, count, copycount;
        const struct in6_addr *group;
        struct ipv6_mc_socklist *pmc;
        struct inet6_dev *idev;
        struct ipv6_pinfo *inet6 = inet6_sk(sk);
        struct ip6_sf_socklist *psl;
        struct net *net = sock_net(sk);

        group = &((struct sockaddr_in6 *)&gsf->gf_group)->sin6_addr;

        if (!ipv6_addr_is_multicast(group))
                return -EINVAL;

        rcu_read_lock();
        idev = ip6_mc_find_dev_rcu(net, group, gsf->gf_interface);

        if (!idev) {
                rcu_read_unlock();
                return -ENODEV;
        }

        err = -EADDRNOTAVAIL;
        /* changes to the ipv6_mc_list require the socket lock and
         * rtnl lock. We have the socket lock and rcu read lock,
         * so reading the list is safe.
         */

        for_each_pmc_rcu(inet6, pmc) {
                if (pmc->ifindex != gsf->gf_interface)
                        continue;
                if (ipv6_addr_equal(group, &pmc->addr))
                        break;
        }
        if (!pmc)               /* must have a prior join */
                goto done;
        gsf->gf_fmode = pmc->sfmode;
        psl = pmc->sflist;
        count = psl ? psl->sl_count : 0;
        read_unlock_bh(&idev->lock);
        rcu_read_unlock();

        copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
        gsf->gf_numsrc = count;
        if (put_user(GROUP_FILTER_SIZE(copycount), optlen) ||
            copy_to_user(optval, gsf, GROUP_FILTER_SIZE(0))) {
                return -EFAULT;
        }
        /* changes to psl require the socket lock, and a write lock
         * on pmc->sflock. We have the socket lock so reading here is safe.
         */
        for (i = 0; i < copycount; i++) {
                struct sockaddr_in6 *psin6;
                struct sockaddr_storage ss;

                psin6 = (struct sockaddr_in6 *)&ss;
                memset(&ss, 0, sizeof(ss));
                psin6->sin6_family = AF_INET6;
                psin6->sin6_addr = psl->sl_addr[i];
                if (copy_to_user(&optval->gf_slist[i], &ss, sizeof(ss)))
                        return -EFAULT;
        }
        return 0;
done:
        read_unlock_bh(&idev->lock);
        rcu_read_unlock();
        return err;
}

bool inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr,
                    const struct in6_addr *src_addr)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct ipv6_mc_socklist *mc;
        struct ip6_sf_socklist *psl;
        bool rv = true;

        rcu_read_lock();
        for_each_pmc_rcu(np, mc) {
                if (ipv6_addr_equal(&mc->addr, mc_addr))
                        break;
        }
        if (!mc) {
                rcu_read_unlock();
                return true;
        }
        read_lock(&mc->sflock);
        psl = mc->sflist;
        if (!psl) {
                rv = mc->sfmode == MCAST_EXCLUDE;
        } else {
                int i;

                for (i = 0; i < psl->sl_count; i++) {
                        if (ipv6_addr_equal(&psl->sl_addr[i], src_addr))
                                break;
                }
                if (mc->sfmode == MCAST_INCLUDE && i >= psl->sl_count)
                        rv = false;
                if (mc->sfmode == MCAST_EXCLUDE && i < psl->sl_count)
                        rv = false;
        }
        read_unlock(&mc->sflock);
        rcu_read_unlock();

        return rv;
}

static void igmp6_group_added(struct ifmcaddr6 *mc)
{
        struct net_device *dev = mc->idev->dev;
        char buf[MAX_ADDR_LEN];

        if (IPV6_ADDR_MC_SCOPE(&mc->mca_addr) <
            IPV6_ADDR_SCOPE_LINKLOCAL)
                return;

        spin_lock_bh(&mc->mca_lock);
        if (!(mc->mca_flags&MAF_LOADED)) {
                mc->mca_flags |= MAF_LOADED;
                if (ndisc_mc_map(&mc->mca_addr, buf, dev, 0) == 0)
                        dev_mc_add(dev, buf);
        }
        spin_unlock_bh(&mc->mca_lock);

        if (!(dev->flags & IFF_UP) || (mc->mca_flags & MAF_NOREPORT))
                return;

        if (mld_in_v1_mode(mc->idev)) {
                igmp6_join_group(mc);
                return;
        }
        /* else v2 */

        /* Based on RFC3810 6.1, for newly added INCLUDE SSM, we
         * should not send filter-mode change record as the mode
         * should be from IN() to IN(A).
         */
        if (mc->mca_sfmode == MCAST_EXCLUDE)
                mc->mca_crcount = mc->idev->mc_qrv;

        mld_ifc_event(mc->idev);
}

static void igmp6_group_dropped(struct ifmcaddr6 *mc)
{
        struct net_device *dev = mc->idev->dev;
        char buf[MAX_ADDR_LEN];

        if (IPV6_ADDR_MC_SCOPE(&mc->mca_addr) <
            IPV6_ADDR_SCOPE_LINKLOCAL)
                return;

        spin_lock_bh(&mc->mca_lock);
        if (mc->mca_flags&MAF_LOADED) {
                mc->mca_flags &= ~MAF_LOADED;
                if (ndisc_mc_map(&mc->mca_addr, buf, dev, 0) == 0)
                        dev_mc_del(dev, buf);
        }

        spin_unlock_bh(&mc->mca_lock);
        if (mc->mca_flags & MAF_NOREPORT)
                return;

        if (!mc->idev->dead)
                igmp6_leave_group(mc);

        spin_lock_bh(&mc->mca_lock);
        if (del_timer(&mc->mca_timer))
                refcount_dec(&mc->mca_refcnt);
        spin_unlock_bh(&mc->mca_lock);
}

/*
 * deleted ifmcaddr6 manipulation
 */
static void mld_add_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
{
        struct ifmcaddr6 *pmc;

        /* this is an "ifmcaddr6" for convenience; only the fields below
         * are actually used. In particular, the refcnt and users are not
         * used for management of the delete list. Using the same structure
         * for deleted items allows change reports to use common code with
         * non-deleted or query-response MCA's.
         */
        pmc = kzalloc(sizeof(*pmc), GFP_ATOMIC);
        if (!pmc)
                return;

        spin_lock_bh(&im->mca_lock);
        spin_lock_init(&pmc->mca_lock);
        pmc->idev = im->idev;
        in6_dev_hold(idev);
        pmc->mca_addr = im->mca_addr;
        pmc->mca_crcount = idev->mc_qrv;
        pmc->mca_sfmode = im->mca_sfmode;
        if (pmc->mca_sfmode == MCAST_INCLUDE) {
                struct ip6_sf_list *psf;

                pmc->mca_tomb = im->mca_tomb;
                pmc->mca_sources = im->mca_sources;
                im->mca_tomb = im->mca_sources = NULL;
                for (psf = pmc->mca_sources; psf; psf = psf->sf_next)
                        psf->sf_crcount = pmc->mca_crcount;
        }
        spin_unlock_bh(&im->mca_lock);

        spin_lock_bh(&idev->mc_lock);
        pmc->next = idev->mc_tomb;
        idev->mc_tomb = pmc;
        spin_unlock_bh(&idev->mc_lock);
}

static void mld_del_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
{
        struct ifmcaddr6 *pmc, *pmc_prev;
        struct ip6_sf_list *psf;
        struct in6_addr *pmca = &im->mca_addr;

        spin_lock_bh(&idev->mc_lock);
        pmc_prev = NULL;
        for (pmc = idev->mc_tomb; pmc; pmc = pmc->next) {
                if (ipv6_addr_equal(&pmc->mca_addr, pmca))
                        break;
                pmc_prev = pmc;
        }
        if (pmc) {
                if (pmc_prev)
                        pmc_prev->next = pmc->next;
                else
                        idev->mc_tomb = pmc->next;
        }
        spin_unlock_bh(&idev->mc_lock);

        spin_lock_bh(&im->mca_lock);
        if (pmc) {
                im->idev = pmc->idev;
                if (im->mca_sfmode == MCAST_INCLUDE) {
                        swap(im->mca_tomb, pmc->mca_tomb);
                        swap(im->mca_sources, pmc->mca_sources);
                        for (psf = im->mca_sources; psf; psf = psf->sf_next)
                                psf->sf_crcount = idev->mc_qrv;
                } else {
                        im->mca_crcount = idev->mc_qrv;
                }
                in6_dev_put(pmc->idev);
                ip6_mc_clear_src(pmc);
                kfree(pmc);
        }
        spin_unlock_bh(&im->mca_lock);
}

static void mld_clear_delrec(struct inet6_dev *idev)
{
        struct ifmcaddr6 *pmc, *nextpmc;

        spin_lock_bh(&idev->mc_lock);
        pmc = idev->mc_tomb;
        idev->mc_tomb = NULL;
        spin_unlock_bh(&idev->mc_lock);

        for (; pmc; pmc = nextpmc) {
                nextpmc = pmc->next;
                ip6_mc_clear_src(pmc);
                in6_dev_put(pmc->idev);
                kfree(pmc);
        }

        /* clear dead sources, too */
        read_lock_bh(&idev->lock);
        for (pmc = idev->mc_list; pmc; pmc = pmc->next) {
                struct ip6_sf_list *psf, *psf_next;

                spin_lock_bh(&pmc->mca_lock);
                psf = pmc->mca_tomb;
                pmc->mca_tomb = NULL;
                spin_unlock_bh(&pmc->mca_lock);
                for (; psf; psf = psf_next) {
                        psf_next = psf->sf_next;
                        kfree(psf);
                }
        }
        read_unlock_bh(&idev->lock);
}

static void mca_get(struct ifmcaddr6 *mc)
{
        refcount_inc(&mc->mca_refcnt);
}

static void ma_put(struct ifmcaddr6 *mc)
{
        if (refcount_dec_and_test(&mc->mca_refcnt)) {
                in6_dev_put(mc->idev);
                kfree(mc);
        }
}

static struct ifmcaddr6 *mca_alloc(struct inet6_dev *idev,
                                   const struct in6_addr *addr,
                                   unsigned int mode)
{
        struct ifmcaddr6 *mc;

        mc = kzalloc(sizeof(*mc), GFP_ATOMIC);
        if (!mc)
                return NULL;

        timer_setup(&mc->mca_timer, igmp6_timer_handler, 0);

        mc->mca_addr = *addr;
        mc->idev = idev; /* reference taken by caller */
        mc->mca_users = 1;
        /* mca_stamp should be updated upon changes */
        mc->mca_cstamp = mc->mca_tstamp = jiffies;
        refcount_set(&mc->mca_refcnt, 1);
        spin_lock_init(&mc->mca_lock);

        mc->mca_sfmode = mode;
        mc->mca_sfcount[mode] = 1;

        if (ipv6_addr_is_ll_all_nodes(&mc->mca_addr) ||
            IPV6_ADDR_MC_SCOPE(&mc->mca_addr) < IPV6_ADDR_SCOPE_LINKLOCAL)
                mc->mca_flags |= MAF_NOREPORT;

        return mc;
}

/*
 *      device multicast group inc (add if not found)
 */
static int __ipv6_dev_mc_inc(struct net_device *dev,
                             const struct in6_addr *addr, unsigned int mode)
{
        struct ifmcaddr6 *mc;
        struct inet6_dev *idev;

        ASSERT_RTNL();

        /* we need to take a reference on idev */
        idev = in6_dev_get(dev);

        if (!idev)
                return -EINVAL;

        write_lock_bh(&idev->lock);
        if (idev->dead) {
                write_unlock_bh(&idev->lock);
                in6_dev_put(idev);
                return -ENODEV;
        }

        for (mc = idev->mc_list; mc; mc = mc->next) {
                if (ipv6_addr_equal(&mc->mca_addr, addr)) {
                        mc->mca_users++;
                        write_unlock_bh(&idev->lock);
                        ip6_mc_add_src(idev, &mc->mca_addr, mode, 0, NULL, 0);
                        in6_dev_put(idev);
                        return 0;
                }
        }

        mc = mca_alloc(idev, addr, mode);
        if (!mc) {
                write_unlock_bh(&idev->lock);
                in6_dev_put(idev);
                return -ENOMEM;
        }

        mc->next = idev->mc_list;
        idev->mc_list = mc;

        /* Hold this for the code below before we unlock,
         * it is already exposed via idev->mc_list.
         */
        mca_get(mc);
        write_unlock_bh(&idev->lock);

        mld_del_delrec(idev, mc);
        igmp6_group_added(mc);
        ma_put(mc);
        return 0;
}

int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr)
{
        return __ipv6_dev_mc_inc(dev, addr, MCAST_EXCLUDE);
}

/*
 *      device multicast group del
 */
int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr)
{
        struct ifmcaddr6 *ma, **map;

        ASSERT_RTNL();

        write_lock_bh(&idev->lock);
        for (map = &idev->mc_list; (ma = *map) != NULL; map = &ma->next) {
                if (ipv6_addr_equal(&ma->mca_addr, addr)) {
                        if (--ma->mca_users == 0) {
                                *map = ma->next;
                                write_unlock_bh(&idev->lock);

                                igmp6_group_dropped(ma);
                                ip6_mc_clear_src(ma);

                                ma_put(ma);
                                return 0;
                        }
                        write_unlock_bh(&idev->lock);
                        return 0;
                }
        }
        write_unlock_bh(&idev->lock);

        return -ENOENT;
}

int ipv6_dev_mc_dec(struct net_device *dev, const struct in6_addr *addr)
{
        struct inet6_dev *idev;
        int err;

        ASSERT_RTNL();

        idev = __in6_dev_get(dev);
        if (!idev)
                err = -ENODEV;
        else
                err = __ipv6_dev_mc_dec(idev, addr);

        return err;
}

/*
 *      check if the interface/address pair is valid
 */
bool ipv6_chk_mcast_addr(struct net_device *dev, const struct in6_addr *group,
                         const struct in6_addr *src_addr)
{
        struct inet6_dev *idev;
        struct ifmcaddr6 *mc;
        bool rv = false;

        rcu_read_lock();
        idev = __in6_dev_get(dev);
        if (idev) {
                read_lock_bh(&idev->lock);
                for (mc = idev->mc_list; mc; mc = mc->next) {
                        if (ipv6_addr_equal(&mc->mca_addr, group))
                                break;
                }
                if (mc) {
                        if (src_addr && !ipv6_addr_any(src_addr)) {
                                struct ip6_sf_list *psf;

                                spin_lock_bh(&mc->mca_lock);
                                for (psf = mc->mca_sources; psf; psf = psf->sf_next) {
                                        if (ipv6_addr_equal(&psf->sf_addr, src_addr))
                                                break;
                                }
                                if (psf)
                                        rv = psf->sf_count[MCAST_INCLUDE] ||
                                                psf->sf_count[MCAST_EXCLUDE] !=
                                                mc->mca_sfcount[MCAST_EXCLUDE];
                                else
                                        rv = mc->mca_sfcount[MCAST_EXCLUDE] != 0;
                                spin_unlock_bh(&mc->mca_lock);
                        } else
                                rv = true; /* don't filter unspecified source */
                }
                read_unlock_bh(&idev->lock);
        }
        rcu_read_unlock();
        return rv;
}

static void mld_gq_start_timer(struct inet6_dev *idev)
{
        unsigned long tv = prandom_u32() % idev->mc_maxdelay;

        idev->mc_gq_running = 1;
        if (!mod_timer(&idev->mc_gq_timer, jiffies+tv+2))
                in6_dev_hold(idev);
}

static void mld_gq_stop_timer(struct inet6_dev *idev)
{
        idev->mc_gq_running = 0;
        if (del_timer(&idev->mc_gq_timer))
                __in6_dev_put(idev);
}

static void mld_ifc_start_timer(struct inet6_dev *idev, unsigned long delay)
{
        unsigned long tv = prandom_u32() % delay;

        if (!mod_timer(&idev->mc_ifc_timer, jiffies+tv+2))
                in6_dev_hold(idev);
}

static void mld_ifc_stop_timer(struct inet6_dev *idev)
{
        idev->mc_ifc_count = 0;
        if (del_timer(&idev->mc_ifc_timer))
                __in6_dev_put(idev);
}

static void mld_dad_start_timer(struct inet6_dev *idev, unsigned long delay)
{
        unsigned long tv = prandom_u32() % delay;

        if (!mod_timer(&idev->mc_dad_timer, jiffies+tv+2))
                in6_dev_hold(idev);
}

static void mld_dad_stop_timer(struct inet6_dev *idev)
{
        if (del_timer(&idev->mc_dad_timer))
                __in6_dev_put(idev);
}

/*
 *      IGMP handling (alias multicast ICMPv6 messages)
 */

static void igmp6_group_queried(struct ifmcaddr6 *ma, unsigned long resptime)
{
        unsigned long delay = resptime;

        /* Do not start timer for these addresses */
        if (ipv6_addr_is_ll_all_nodes(&ma->mca_addr) ||
            IPV6_ADDR_MC_SCOPE(&ma->mca_addr) < IPV6_ADDR_SCOPE_LINKLOCAL)
                return;

        if (del_timer(&ma->mca_timer)) {
                refcount_dec(&ma->mca_refcnt);
                delay = ma->mca_timer.expires - jiffies;
        }

        if (delay >= resptime)
                delay = prandom_u32() % resptime;

        ma->mca_timer.expires = jiffies + delay;
        if (!mod_timer(&ma->mca_timer, jiffies + delay))
                refcount_inc(&ma->mca_refcnt);
        ma->mca_flags |= MAF_TIMER_RUNNING;
}

/* mark EXCLUDE-mode sources */
static bool mld_xmarksources(struct ifmcaddr6 *pmc, int nsrcs,
                             const struct in6_addr *srcs)
{
        struct ip6_sf_list *psf;
        int i, scount;

        scount = 0;
        for (psf = pmc->mca_sources; psf; psf = psf->sf_next) {
                if (scount == nsrcs)
                        break;
                for (i = 0; i < nsrcs; i++) {
                        /* skip inactive filters */
                        if (psf->sf_count[MCAST_INCLUDE] ||
                            pmc->mca_sfcount[MCAST_EXCLUDE] !=
                            psf->sf_count[MCAST_EXCLUDE])
                                break;
                        if (ipv6_addr_equal(&srcs[i], &psf->sf_addr)) {
                                scount++;
                                break;
                        }
                }
        }
        pmc->mca_flags &= ~MAF_GSQUERY;
        if (scount == nsrcs)    /* all sources excluded */
                return false;
        return true;
}

static bool mld_marksources(struct ifmcaddr6 *pmc, int nsrcs,
                            const struct in6_addr *srcs)
{
        struct ip6_sf_list *psf;
        int i, scount;

        if (pmc->mca_sfmode == MCAST_EXCLUDE)
                return mld_xmarksources(pmc, nsrcs, srcs);

        /* mark INCLUDE-mode sources */

        scount = 0;
        for (psf = pmc->mca_sources; psf; psf = psf->sf_next) {
                if (scount == nsrcs)
                        break;
                for (i = 0; i < nsrcs; i++) {
                        if (ipv6_addr_equal(&srcs[i], &psf->sf_addr)) {
                                psf->sf_gsresp = 1;
                                scount++;
                                break;
                        }
                }
        }
        if (!scount) {
                pmc->mca_flags &= ~MAF_GSQUERY;
                return false;
        }
        pmc->mca_flags |= MAF_GSQUERY;
        return true;
}

static int mld_force_mld_version(const struct inet6_dev *idev)
{
        /* Normally, both are 0 here. If enforcement to a particular is
         * being used, individual device enforcement will have a lower
         * precedence over 'all' device (.../conf/all/force_mld_version).
         */

        if (dev_net(idev->dev)->ipv6.devconf_all->force_mld_version != 0)
                return dev_net(idev->dev)->ipv6.devconf_all->force_mld_version;
        else
                return idev->cnf.force_mld_version;
}

static bool mld_in_v2_mode_only(const struct inet6_dev *idev)
{
        return mld_force_mld_version(idev) == 2;
}

static bool mld_in_v1_mode_only(const struct inet6_dev *idev)
{
        return mld_force_mld_version(idev) == 1;
}

static bool mld_in_v1_mode(const struct inet6_dev *idev)
{
        if (mld_in_v2_mode_only(idev))
                return false;
        if (mld_in_v1_mode_only(idev))
                return true;
        if (idev->mc_v1_seen && time_before(jiffies, idev->mc_v1_seen))
                return true;

        return false;
}

static void mld_set_v1_mode(struct inet6_dev *idev)
{
        /* RFC3810, relevant sections:
         *  - 9.1. Robustness Variable
         *  - 9.2. Query Interval
         *  - 9.3. Query Response Interval
         *  - 9.12. Older Version Querier Present Timeout
         */
        unsigned long switchback;

        switchback = (idev->mc_qrv * idev->mc_qi) + idev->mc_qri;

        idev->mc_v1_seen = jiffies + switchback;
}

static void mld_update_qrv(struct inet6_dev *idev,
                           const struct mld2_query *mlh2)
{
        /* RFC3810, relevant sections:
         *  - 5.1.8. QRV (Querier's Robustness Variable)
         *  - 9.1. Robustness Variable
         */

        /* The value of the Robustness Variable MUST NOT be zero,
         * and SHOULD NOT be one. Catch this here if we ever run
         * into such a case in future.
         */
        const int min_qrv = min(MLD_QRV_DEFAULT, sysctl_mld_qrv);
        WARN_ON(idev->mc_qrv == 0);

        if (mlh2->mld2q_qrv > 0)
                idev->mc_qrv = mlh2->mld2q_qrv;

        if (unlikely(idev->mc_qrv < min_qrv)) {
                net_warn_ratelimited("IPv6: MLD: clamping QRV from %u to %u!\n",
                                     idev->mc_qrv, min_qrv);
                idev->mc_qrv = min_qrv;
        }
}

static void mld_update_qi(struct inet6_dev *idev,
                          const struct mld2_query *mlh2)
{
        /* RFC3810, relevant sections:
         *  - 5.1.9. QQIC (Querier's Query Interval Code)
         *  - 9.2. Query Interval
         *  - 9.12. Older Version Querier Present Timeout
         *    (the [Query Interval] in the last Query received)
         */
        unsigned long mc_qqi;

        if (mlh2->mld2q_qqic < 128) {
                mc_qqi = mlh2->mld2q_qqic;
        } else {
                unsigned long mc_man, mc_exp;

                mc_exp = MLDV2_QQIC_EXP(mlh2->mld2q_qqic);
                mc_man = MLDV2_QQIC_MAN(mlh2->mld2q_qqic);

                mc_qqi = (mc_man | 0x10) << (mc_exp + 3);
        }

        idev->mc_qi = mc_qqi * HZ;
}

static void mld_update_qri(struct inet6_dev *idev,
                           const struct mld2_query *mlh2)
{
        /* RFC3810, relevant sections:
         *  - 5.1.3. Maximum Response Code
         *  - 9.3. Query Response Interval
         */
        idev->mc_qri = msecs_to_jiffies(mldv2_mrc(mlh2));
}

static int mld_process_v1(struct inet6_dev *idev, struct mld_msg *mld,
                          unsigned long *max_delay, bool v1_query)
{
        unsigned long mldv1_md;

        /* Ignore v1 queries */
        if (mld_in_v2_mode_only(idev))
                return -EINVAL;

        mldv1_md = ntohs(mld->mld_maxdelay);

        /* When in MLDv1 fallback and a MLDv2 router start-up being
         * unaware of current MLDv1 operation, the MRC == MRD mapping
         * only works when the exponential algorithm is not being
         * used (as MLDv1 is unaware of such things).
         *
         * According to the RFC author, the MLDv2 implementations
         * he's aware of all use a MRC < 32768 on start up queries.
         *
         * Thus, should we *ever* encounter something else larger
         * than that, just assume the maximum possible within our
         * reach.
         */
        if (!v1_query)
                mldv1_md = min(mldv1_md, MLDV1_MRD_MAX_COMPAT);

        *max_delay = max(msecs_to_jiffies(mldv1_md), 1UL);

        /* MLDv1 router present: we need to go into v1 mode *only*
         * when an MLDv1 query is received as per section 9.12. of
         * RFC3810! And we know from RFC2710 section 3.7 that MLDv1
         * queries MUST be of exactly 24 octets.
         */
        if (v1_query)
                mld_set_v1_mode(idev);

        /* cancel MLDv2 report timer */
        mld_gq_stop_timer(idev);
        /* cancel the interface change timer */
        mld_ifc_stop_timer(idev);
        /* clear deleted report items */
        mld_clear_delrec(idev);

        return 0;
}

static int mld_process_v2(struct inet6_dev *idev, struct mld2_query *mld,
                          unsigned long *max_delay)
{
        *max_delay = max(msecs_to_jiffies(mldv2_mrc(mld)), 1UL);

        mld_update_qrv(idev, mld);
        mld_update_qi(idev, mld);
        mld_update_qri(idev, mld);

        idev->mc_maxdelay = *max_delay;

        return 0;
}

/* called with rcu_read_lock() */
int igmp6_event_query(struct sk_buff *skb)
{
        struct mld2_query *mlh2 = NULL;
        struct ifmcaddr6 *ma;
        const struct in6_addr *group;
        unsigned long max_delay;
        struct inet6_dev *idev;
        struct mld_msg *mld;
        int group_type;
        int mark = 0;
        int len, err;

        if (!pskb_may_pull(skb, sizeof(struct in6_addr)))
                return -EINVAL;

        /* compute payload length excluding extension headers */
        len = ntohs(ipv6_hdr(skb)->payload_len) + sizeof(struct ipv6hdr);
        len -= skb_network_header_len(skb);

        /* RFC3810 6.2
         * Upon reception of an MLD message that contains a Query, the node
         * checks if the source address of the message is a valid link-local
         * address, if the Hop Limit is set to 1, and if the Router Alert
         * option is present in the Hop-By-Hop Options header of the IPv6
         * packet.  If any of these checks fails, the packet is dropped.
         */
        if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL) ||
            ipv6_hdr(skb)->hop_limit != 1 ||
            !(IP6CB(skb)->flags & IP6SKB_ROUTERALERT) ||
            IP6CB(skb)->ra != htons(IPV6_OPT_ROUTERALERT_MLD))
                return -EINVAL;

        idev = __in6_dev_get(skb->dev);
        if (!idev)
                return 0;

        mld = (struct mld_msg *)icmp6_hdr(skb);
        group = &mld->mld_mca;
        group_type = ipv6_addr_type(group);

        if (group_type != IPV6_ADDR_ANY &&
            !(group_type&IPV6_ADDR_MULTICAST))
                return -EINVAL;

        if (len < MLD_V1_QUERY_LEN) {
                return -EINVAL;
        } else if (len == MLD_V1_QUERY_LEN || mld_in_v1_mode(idev)) {
                err = mld_process_v1(idev, mld, &max_delay,
                                     len == MLD_V1_QUERY_LEN);
                if (err < 0)
                        return err;
        } else if (len >= MLD_V2_QUERY_LEN_MIN) {
                int srcs_offset = sizeof(struct mld2_query) -
                                  sizeof(struct icmp6hdr);

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

                mlh2 = (struct mld2_query *)skb_transport_header(skb);

                err = mld_process_v2(idev, mlh2, &max_delay);
                if (err < 0)
                        return err;

                if (group_type == IPV6_ADDR_ANY) { /* general query */
                        if (mlh2->mld2q_nsrcs)
                                return -EINVAL; /* no sources allowed */

                        mld_gq_start_timer(idev);
                        return 0;
                }
                /* mark sources to include, if group & source-specific */
                if (mlh2->mld2q_nsrcs != 0) {
                        if (!pskb_may_pull(skb, srcs_offset +
                            ntohs(mlh2->mld2q_nsrcs) * sizeof(struct in6_addr)))
                                return -EINVAL;

                        mlh2 = (struct mld2_query *)skb_transport_header(skb);
                        mark = 1;
                }
        } else {
                return -EINVAL;
        }

        read_lock_bh(&idev->lock);
        if (group_type == IPV6_ADDR_ANY) {
                for (ma = idev->mc_list; ma; ma = ma->next) {
                        spin_lock_bh(&ma->mca_lock);
                        igmp6_group_queried(ma, max_delay);
                        spin_unlock_bh(&ma->mca_lock);
                }
        } else {
                for (ma = idev->mc_list; ma; ma = ma->next) {
                        if (!ipv6_addr_equal(group, &ma->mca_addr))
                                continue;
                        spin_lock_bh(&ma->mca_lock);
                        if (ma->mca_flags & MAF_TIMER_RUNNING) {
                                /* gsquery <- gsquery && mark */
                                if (!mark)
                                        ma->mca_flags &= ~MAF_GSQUERY;
                        } else {
                                /* gsquery <- mark */
                                if (mark)
                                        ma->mca_flags |= MAF_GSQUERY;
                                else
                                        ma->mca_flags &= ~MAF_GSQUERY;
                        }
                        if (!(ma->mca_flags & MAF_GSQUERY) ||
                            mld_marksources(ma, ntohs(mlh2->mld2q_nsrcs), mlh2->mld2q_srcs))
                                igmp6_group_queried(ma, max_delay);
                        spin_unlock_bh(&ma->mca_lock);
                        break;
                }
        }
        read_unlock_bh(&idev->lock);

        return 0;
}

/* called with rcu_read_lock() */
int igmp6_event_report(struct sk_buff *skb)
{
        struct ifmcaddr6 *ma;
        struct inet6_dev *idev;
        struct mld_msg *mld;
        int addr_type;

        /* Our own report looped back. Ignore it. */
        if (skb->pkt_type == PACKET_LOOPBACK)
                return 0;

        /* send our report if the MC router may not have heard this report */
        if (skb->pkt_type != PACKET_MULTICAST &&
            skb->pkt_type != PACKET_BROADCAST)
                return 0;

        if (!pskb_may_pull(skb, sizeof(*mld) - sizeof(struct icmp6hdr)))
                return -EINVAL;

        mld = (struct mld_msg *)icmp6_hdr(skb);

        /* Drop reports with not link local source */
        addr_type = ipv6_addr_type(&ipv6_hdr(skb)->saddr);
        if (addr_type != IPV6_ADDR_ANY &&
            !(addr_type&IPV6_ADDR_LINKLOCAL))
                return -EINVAL;

        idev = __in6_dev_get(skb->dev);
        if (!idev)
                return -ENODEV;

        /*
         *      Cancel the timer for this group
         */

        read_lock_bh(&idev->lock);
        for (ma = idev->mc_list; ma; ma = ma->next) {
                if (ipv6_addr_equal(&ma->mca_addr, &mld->mld_mca)) {
                        spin_lock(&ma->mca_lock);
                        if (del_timer(&ma->mca_timer))
                                refcount_dec(&ma->mca_refcnt);
                        ma->mca_flags &= ~(MAF_LAST_REPORTER|MAF_TIMER_RUNNING);
                        spin_unlock(&ma->mca_lock);
                        break;
                }
        }
        read_unlock_bh(&idev->lock);
        return 0;
}

static bool is_in(struct ifmcaddr6 *pmc, struct ip6_sf_list *psf, int type,
                  int gdeleted, int sdeleted)
{
        switch (type) {
        case MLD2_MODE_IS_INCLUDE:
        case MLD2_MODE_IS_EXCLUDE:
                if (gdeleted || sdeleted)
                        return false;
                if (!((pmc->mca_flags & MAF_GSQUERY) && !psf->sf_gsresp)) {
                        if (pmc->mca_sfmode == MCAST_INCLUDE)
                                return true;
                        /* don't include if this source is excluded
                         * in all filters
                         */
                        if (psf->sf_count[MCAST_INCLUDE])
                                return type == MLD2_MODE_IS_INCLUDE;
                        return pmc->mca_sfcount[MCAST_EXCLUDE] ==
                                psf->sf_count[MCAST_EXCLUDE];
                }
                return false;
        case MLD2_CHANGE_TO_INCLUDE:
                if (gdeleted || sdeleted)
                        return false;
                return psf->sf_count[MCAST_INCLUDE] != 0;
        case MLD2_CHANGE_TO_EXCLUDE:
                if (gdeleted || sdeleted)
                        return false;
                if (pmc->mca_sfcount[MCAST_EXCLUDE] == 0 ||
                    psf->sf_count[MCAST_INCLUDE])
                        return false;
                return pmc->mca_sfcount[MCAST_EXCLUDE] ==
                        psf->sf_count[MCAST_EXCLUDE];
        case MLD2_ALLOW_NEW_SOURCES:
                if (gdeleted || !psf->sf_crcount)
                        return false;
                return (pmc->mca_sfmode == MCAST_INCLUDE) ^ sdeleted;
        case MLD2_BLOCK_OLD_SOURCES:
                if (pmc->mca_sfmode == MCAST_INCLUDE)
                        return gdeleted || (psf->sf_crcount && sdeleted);
                return psf->sf_crcount && !gdeleted && !sdeleted;
        }
        return false;
}

static int
mld_scount(struct ifmcaddr6 *pmc, int type, int gdeleted, int sdeleted)
{
        struct ip6_sf_list *psf;
        int scount = 0;

        for (psf = pmc->mca_sources; psf; psf = psf->sf_next) {
                if (!is_in(pmc, psf, type, gdeleted, sdeleted))
                        continue;
                scount++;
        }
        return scount;
}

static void ip6_mc_hdr(struct sock *sk, struct sk_buff *skb,
                       struct net_device *dev,
                       const struct in6_addr *saddr,
                       const struct in6_addr *daddr,
                       int proto, int len)
{
        struct ipv6hdr *hdr;

        skb->protocol = htons(ETH_P_IPV6);
        skb->dev = dev;

        skb_reset_network_header(skb);
        skb_put(skb, sizeof(struct ipv6hdr));
        hdr = ipv6_hdr(skb);

        ip6_flow_hdr(hdr, 0, 0);

        hdr->payload_len = htons(len);
        hdr->nexthdr = proto;
        hdr->hop_limit = inet6_sk(sk)->hop_limit;

        hdr->saddr = *saddr;
        hdr->daddr = *daddr;
}

static struct sk_buff *mld_newpack(struct inet6_dev *idev, unsigned int mtu)
{
        struct net_device *dev = idev->dev;
        struct net *net = dev_net(dev);
        struct sock *sk = net->ipv6.igmp_sk;
        struct sk_buff *skb;
        struct mld2_report *pmr;
        struct in6_addr addr_buf;
        const struct in6_addr *saddr;
        int hlen = LL_RESERVED_SPACE(dev);
        int tlen = dev->needed_tailroom;
        unsigned int size = mtu + hlen + tlen;
        int err;
        u8 ra[8] = { IPPROTO_ICMPV6, 0,
                     IPV6_TLV_ROUTERALERT, 2, 0, 0,
                     IPV6_TLV_PADN, 0 };

        /* we assume size > sizeof(ra) here */
        /* limit our allocations to order-0 page */
        size = min_t(int, size, SKB_MAX_ORDER(0, 0));
        skb = sock_alloc_send_skb(sk, size, 1, &err);

        if (!skb)
                return NULL;

        skb->priority = TC_PRIO_CONTROL;
        skb_reserve(skb, hlen);
        skb_tailroom_reserve(skb, mtu, tlen);

        if (__ipv6_get_lladdr(idev, &addr_buf, IFA_F_TENTATIVE)) {
                /* <draft-ietf-magma-mld-source-05.txt>:
                 * use unspecified address as the source address
                 * when a valid link-local address is not available.
                 */
                saddr = &in6addr_any;
        } else
                saddr = &addr_buf;

        ip6_mc_hdr(sk, skb, dev, saddr, &mld2_all_mcr, NEXTHDR_HOP, 0);

        skb_put_data(skb, ra, sizeof(ra));

        skb_set_transport_header(skb, skb_tail_pointer(skb) - skb->data);
        skb_put(skb, sizeof(*pmr));
        pmr = (struct mld2_report *)skb_transport_header(skb);
        pmr->mld2r_type = ICMPV6_MLD2_REPORT;
        pmr->mld2r_resv1 = 0;
        pmr->mld2r_cksum = 0;
        pmr->mld2r_resv2 = 0;
        pmr->mld2r_ngrec = 0;
        return skb;
}

static void mld_sendpack(struct sk_buff *skb)
{
        struct ipv6hdr *pip6 = ipv6_hdr(skb);
        struct mld2_report *pmr =
                              (struct mld2_report *)skb_transport_header(skb);
        int payload_len, mldlen;
        struct inet6_dev *idev;
        struct net *net = dev_net(skb->dev);
        int err;
        struct flowi6 fl6;
        struct dst_entry *dst;

        rcu_read_lock();
        idev = __in6_dev_get(skb->dev);
        IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);

        payload_len = (skb_tail_pointer(skb) - skb_network_header(skb)) -
                sizeof(*pip6);
        mldlen = skb_tail_pointer(skb) - skb_transport_header(skb);
        pip6->payload_len = htons(payload_len);

        pmr->mld2r_cksum = csum_ipv6_magic(&pip6->saddr, &pip6->daddr, mldlen,
                                           IPPROTO_ICMPV6,
                                           csum_partial(skb_transport_header(skb),
                                                        mldlen, 0));

        icmpv6_flow_init(net->ipv6.igmp_sk, &fl6, ICMPV6_MLD2_REPORT,
                         &ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
                         skb->dev->ifindex);
        dst = icmp6_dst_alloc(skb->dev, &fl6);

        err = 0;
        if (IS_ERR(dst)) {
                err = PTR_ERR(dst);
                dst = NULL;
        }
        skb_dst_set(skb, dst);
        if (err)
                goto err_out;

        err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
                      net, net->ipv6.igmp_sk, skb, NULL, skb->dev,
                      dst_output);
out:
        if (!err) {
                ICMP6MSGOUT_INC_STATS(net, idev, ICMPV6_MLD2_REPORT);
                ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
        } else {
                IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
        }

        rcu_read_unlock();
        return;

err_out:
        kfree_skb(skb);
        goto out;
}

static int grec_size(struct ifmcaddr6 *pmc, int type, int gdel, int sdel)
{
        return sizeof(struct mld2_grec) + 16 * mld_scount(pmc,type,gdel,sdel);
}

static struct sk_buff *add_grhead(struct sk_buff *skb, struct ifmcaddr6 *pmc,
        int type, struct mld2_grec **ppgr, unsigned int mtu)
{
        struct mld2_report *pmr;
        struct mld2_grec *pgr;

        if (!skb) {
                skb = mld_newpack(pmc->idev, mtu);
                if (!skb)
                        return NULL;
        }
        pgr = skb_put(skb, sizeof(struct mld2_grec));
        pgr->grec_type = type;
        pgr->grec_auxwords = 0;
        pgr->grec_nsrcs = 0;
        pgr->grec_mca = pmc->mca_addr;  /* structure copy */
        pmr = (struct mld2_report *)skb_transport_header(skb);
        pmr->mld2r_ngrec = htons(ntohs(pmr->mld2r_ngrec)+1);
        *ppgr = pgr;
        return skb;
}

#define AVAILABLE(skb)  ((skb) ? skb_availroom(skb) : 0)

static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,
        int type, int gdeleted, int sdeleted, int crsend)
{
        struct inet6_dev *idev = pmc->idev;
        struct net_device *dev = idev->dev;
        struct mld2_report *pmr;
        struct mld2_grec *pgr = NULL;
        struct ip6_sf_list *psf, *psf_next, *psf_prev, **psf_list;
        int scount, stotal, first, isquery, truncate;
        unsigned int mtu;

        if (pmc->mca_flags & MAF_NOREPORT)
                return skb;

        mtu = READ_ONCE(dev->mtu);
        if (mtu < IPV6_MIN_MTU)
                return skb;

        isquery = type == MLD2_MODE_IS_INCLUDE ||
                  type == MLD2_MODE_IS_EXCLUDE;
        truncate = type == MLD2_MODE_IS_EXCLUDE ||
                    type == MLD2_CHANGE_TO_EXCLUDE;

        stotal = scount = 0;

        psf_list = sdeleted ? &pmc->mca_tomb : &pmc->mca_sources;

        if (!*psf_list)
                goto empty_source;

        pmr = skb ? (struct mld2_report *)skb_transport_header(skb) : NULL;

        /* EX and TO_EX get a fresh packet, if needed */
        if (truncate) {
                if (pmr && pmr->mld2r_ngrec &&
                    AVAILABLE(skb) < grec_size(pmc, type, gdeleted, sdeleted)) {
                        if (skb)
                                mld_sendpack(skb);
                        skb = mld_newpack(idev, mtu);
                }
        }
        first = 1;
        psf_prev = NULL;
        for (psf = *psf_list; psf; psf = psf_next) {
                struct in6_addr *psrc;

                psf_next = psf->sf_next;

                if (!is_in(pmc, psf, type, gdeleted, sdeleted) && !crsend) {
                        psf_prev = psf;
                        continue;
                }

                /* Based on RFC3810 6.1. Should not send source-list change
                 * records when there is a filter mode change.
                 */
                if (((gdeleted && pmc->mca_sfmode == MCAST_EXCLUDE) ||
                     (!gdeleted && pmc->mca_crcount)) &&
                    (type == MLD2_ALLOW_NEW_SOURCES ||
                     type == MLD2_BLOCK_OLD_SOURCES) && psf->sf_crcount)
                        goto decrease_sf_crcount;

                /* clear marks on query responses */
                if (isquery)
                        psf->sf_gsresp = 0;

                if (AVAILABLE(skb) < sizeof(*psrc) +
                    first*sizeof(struct mld2_grec)) {
                        if (truncate && !first)
                                break;   /* truncate these */
                        if (pgr)
                                pgr->grec_nsrcs = htons(scount);
                        if (skb)
                                mld_sendpack(skb);
                        skb = mld_newpack(idev, mtu);
                        first = 1;
                        scount = 0;
                }
                if (first) {
                        skb = add_grhead(skb, pmc, type, &pgr, mtu);
                        first = 0;
                }
                if (!skb)
                        return NULL;
                psrc = skb_put(skb, sizeof(*psrc));
                *psrc = psf->sf_addr;
                scount++; stotal++;
                if ((type == MLD2_ALLOW_NEW_SOURCES ||
                     type == MLD2_BLOCK_OLD_SOURCES) && psf->sf_crcount) {
decrease_sf_crcount:
                        psf->sf_crcount--;
                        if ((sdeleted || gdeleted) && psf->sf_crcount == 0) {
                                if (psf_prev)
                                        psf_prev->sf_next = psf->sf_next;
                                else
                                        *psf_list = psf->sf_next;
                                kfree(psf);
                                continue;
                        }
                }
                psf_prev = psf;
        }

empty_source:
        if (!stotal) {
                if (type == MLD2_ALLOW_NEW_SOURCES ||
                    type == MLD2_BLOCK_OLD_SOURCES)
                        return skb;
                if (pmc->mca_crcount || isquery || crsend) {
                        /* make sure we have room for group header */
                        if (skb && AVAILABLE(skb) < sizeof(struct mld2_grec)) {
                                mld_sendpack(skb);
                                skb = NULL; /* add_grhead will get a new one */
                        }
                        skb = add_grhead(skb, pmc, type, &pgr, mtu);
                }
        }
        if (pgr)
                pgr->grec_nsrcs = htons(scount);

        if (isquery)
                pmc->mca_flags &= ~MAF_GSQUERY; /* clear query state */
        return skb;
}

static void mld_send_report(struct inet6_dev *idev, struct ifmcaddr6 *pmc)
{
        struct sk_buff *skb = NULL;
        int type;

        read_lock_bh(&idev->lock);
        if (!pmc) {
                for (pmc = idev->mc_list; pmc; pmc = pmc->next) {
                        if (pmc->mca_flags & MAF_NOREPORT)
                                continue;
                        spin_lock_bh(&pmc->mca_lock);
                        if (pmc->mca_sfcount[MCAST_EXCLUDE])
                                type = MLD2_MODE_IS_EXCLUDE;
                        else
                                type = MLD2_MODE_IS_INCLUDE;
                        skb = add_grec(skb, pmc, type, 0, 0, 0);
                        spin_unlock_bh(&pmc->mca_lock);
                }
        } else {
                spin_lock_bh(&pmc->mca_lock);
                if (pmc->mca_sfcount[MCAST_EXCLUDE])
                        type = MLD2_MODE_IS_EXCLUDE;
                else
                        type = MLD2_MODE_IS_INCLUDE;
                skb = add_grec(skb, pmc, type, 0, 0, 0);
                spin_unlock_bh(&pmc->mca_lock);
        }
        read_unlock_bh(&idev->lock);
        if (skb)
                mld_sendpack(skb);
}

/*
 * remove zero-count source records from a source filter list
 */
static void mld_clear_zeros(struct ip6_sf_list **ppsf)
{
        struct ip6_sf_list *psf_prev, *psf_next, *psf;

        psf_prev = NULL;
        for (psf = *ppsf; psf; psf = psf_next) {
                psf_next = psf->sf_next;
                if (psf->sf_crcount == 0) {
                        if (psf_prev)
                                psf_prev->sf_next = psf->sf_next;
                        else
                                *ppsf = psf->sf_next;
                        kfree(psf);
                } else
                        psf_prev = psf;
        }
}

static void mld_send_cr(struct inet6_dev *idev)
{
        struct ifmcaddr6 *pmc, *pmc_prev, *pmc_next;
        struct sk_buff *skb = NULL;
        int type, dtype;

        read_lock_bh(&idev->lock);
        spin_lock(&idev->mc_lock);

        /* deleted MCA's */
        pmc_prev = NULL;
        for (pmc = idev->mc_tomb; pmc; pmc = pmc_next) {
                pmc_next = pmc->next;
                if (pmc->mca_sfmode == MCAST_INCLUDE) {
                        type = MLD2_BLOCK_OLD_SOURCES;
                        dtype = MLD2_BLOCK_OLD_SOURCES;
                        skb = add_grec(skb, pmc, type, 1, 0, 0);
                        skb = add_grec(skb, pmc, dtype, 1, 1, 0);
                }
                if (pmc->mca_crcount) {
                        if (pmc->mca_sfmode == MCAST_EXCLUDE) {
                                type = MLD2_CHANGE_TO_INCLUDE;
                                skb = add_grec(skb, pmc, type, 1, 0, 0);
                        }
                        pmc->mca_crcount--;
                        if (pmc->mca_crcount == 0) {
                                mld_clear_zeros(&pmc->mca_tomb);
                                mld_clear_zeros(&pmc->mca_sources);
                        }
                }
                if (pmc->mca_crcount == 0 && !pmc->mca_tomb &&
                    !pmc->mca_sources) {
                        if (pmc_prev)
                                pmc_prev->next = pmc_next;
                        else
                                idev->mc_tomb = pmc_next;
                        in6_dev_put(pmc->idev);
                        kfree(pmc);
                } else
                        pmc_prev = pmc;
        }
        spin_unlock(&idev->mc_lock);

        /* change recs */
        for (pmc = idev->mc_list; pmc; pmc = pmc->next) {
                spin_lock_bh(&pmc->mca_lock);
                if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
                        type = MLD2_BLOCK_OLD_SOURCES;
                        dtype = MLD2_ALLOW_NEW_SOURCES;
                } else {
                        type = MLD2_ALLOW_NEW_SOURCES;
                        dtype = MLD2_BLOCK_OLD_SOURCES;
                }
                skb = add_grec(skb, pmc, type, 0, 0, 0);
                skb = add_grec(skb, pmc, dtype, 0, 1, 0);       /* deleted sources */

                /* filter mode changes */
                if (pmc->mca_crcount) {
                        if (pmc->mca_sfmode == MCAST_EXCLUDE)
                                type = MLD2_CHANGE_TO_EXCLUDE;
                        else
                                type = MLD2_CHANGE_TO_INCLUDE;
                        skb = add_grec(skb, pmc, type, 0, 0, 0);
                        pmc->mca_crcount--;
                }
                spin_unlock_bh(&pmc->mca_lock);
        }
        read_unlock_bh(&idev->lock);
        if (!skb)
                return;
        (void) mld_sendpack(skb);
}

static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
{
        struct net *net = dev_net(dev);
        struct sock *sk = net->ipv6.igmp_sk;
        struct inet6_dev *idev;
        struct sk_buff *skb;
        struct mld_msg *hdr;
        const struct in6_addr *snd_addr, *saddr;
        struct in6_addr addr_buf;
        int hlen = LL_RESERVED_SPACE(dev);
        int tlen = dev->needed_tailroom;
        int err, len, payload_len, full_len;
        u8 ra[8] = { IPPROTO_ICMPV6, 0,
                     IPV6_TLV_ROUTERALERT, 2, 0, 0,
                     IPV6_TLV_PADN, 0 };
        struct flowi6 fl6;
        struct dst_entry *dst;

        if (type == ICMPV6_MGM_REDUCTION)
                snd_addr = &in6addr_linklocal_allrouters;
        else
                snd_addr = addr;

        len = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
        payload_len = len + sizeof(ra);
        full_len = sizeof(struct ipv6hdr) + payload_len;

        rcu_read_lock();
        IP6_UPD_PO_STATS(net, __in6_dev_get(dev),
                      IPSTATS_MIB_OUT, full_len);
        rcu_read_unlock();

        skb = sock_alloc_send_skb(sk, hlen + tlen + full_len, 1, &err);

        if (!skb) {
                rcu_read_lock();
                IP6_INC_STATS(net, __in6_dev_get(dev),
                              IPSTATS_MIB_OUTDISCARDS);
                rcu_read_unlock();
                return;
        }
        skb->priority = TC_PRIO_CONTROL;
        skb_reserve(skb, hlen);

        if (ipv6_get_lladdr(dev, &addr_buf, IFA_F_TENTATIVE)) {
                /* <draft-ietf-magma-mld-source-05.txt>:
                 * use unspecified address as the source address
                 * when a valid link-local address is not available.
                 */
                saddr = &in6addr_any;
        } else
                saddr = &addr_buf;

        ip6_mc_hdr(sk, skb, dev, saddr, snd_addr, NEXTHDR_HOP, payload_len);

        skb_put_data(skb, ra, sizeof(ra));

        hdr = skb_put_zero(skb, sizeof(struct mld_msg));
        hdr->mld_type = type;
        hdr->mld_mca = *addr;

        hdr->mld_cksum = csum_ipv6_magic(saddr, snd_addr, len,
                                         IPPROTO_ICMPV6,
                                         csum_partial(hdr, len, 0));

        rcu_read_lock();
        idev = __in6_dev_get(skb->dev);

        icmpv6_flow_init(sk, &fl6, type,
                         &ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
                         skb->dev->ifindex);
        dst = icmp6_dst_alloc(skb->dev, &fl6);
        if (IS_ERR(dst)) {
                err = PTR_ERR(dst);
                goto err_out;
        }

        skb_dst_set(skb, dst);
        err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
                      net, sk, skb, NULL, skb->dev,
                      dst_output);
out:
        if (!err) {
                ICMP6MSGOUT_INC_STATS(net, idev, type);
                ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
        } else
                IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);

        rcu_read_unlock();
        return;

err_out:
        kfree_skb(skb);
        goto out;
}

static void mld_send_initial_cr(struct inet6_dev *idev)
{
        struct sk_buff *skb;
        struct ifmcaddr6 *pmc;
        int type;

        if (mld_in_v1_mode(idev))
                return;

        skb = NULL;
        read_lock_bh(&idev->lock);
        for (pmc = idev->mc_list; pmc; pmc = pmc->next) {
                spin_lock_bh(&pmc->mca_lock);
                if (pmc->mca_sfcount[MCAST_EXCLUDE])
                        type = MLD2_CHANGE_TO_EXCLUDE;
                else
                        type = MLD2_ALLOW_NEW_SOURCES;
                skb = add_grec(skb, pmc, type, 0, 0, 1);
                spin_unlock_bh(&pmc->mca_lock);
        }
        read_unlock_bh(&idev->lock);
        if (skb)
                mld_sendpack(skb);
}

void ipv6_mc_dad_complete(struct inet6_dev *idev)
{
        idev->mc_dad_count = idev->mc_qrv;
        if (idev->mc_dad_count) {
                mld_send_initial_cr(idev);
                idev->mc_dad_count--;
                if (idev->mc_dad_count)
                        mld_dad_start_timer(idev,
                                            unsolicited_report_interval(idev));
        }
}

static void mld_dad_timer_expire(struct timer_list *t)
{
        struct inet6_dev *idev = from_timer(idev, t, mc_dad_timer);

        mld_send_initial_cr(idev);
        if (idev->mc_dad_count) {
                idev->mc_dad_count--;
                if (idev->mc_dad_count)
                        mld_dad_start_timer(idev,
                                            unsolicited_report_interval(idev));
        }
        in6_dev_put(idev);
}

static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
        const struct in6_addr *psfsrc)
{
        struct ip6_sf_list *psf, *psf_prev;
        int rv = 0;

        psf_prev = NULL;
        for (psf = pmc->mca_sources; psf; psf = psf->sf_next) {
                if (ipv6_addr_equal(&psf->sf_addr, psfsrc))
                        break;
                psf_prev = psf;
        }
        if (!psf || psf->sf_count[sfmode] == 0) {
                /* source filter not found, or count wrong =>  bug */
                return -ESRCH;
        }
        psf->sf_count[sfmode]--;
        if (!psf->sf_count[MCAST_INCLUDE] && !psf->sf_count[MCAST_EXCLUDE]) {
                struct inet6_dev *idev = pmc->idev;

                /* no more filters for this source */
                if (psf_prev)
                        psf_prev->sf_next = psf->sf_next;
                else
                        pmc->mca_sources = psf->sf_next;
                if (psf->sf_oldin && !(pmc->mca_flags & MAF_NOREPORT) &&
                    !mld_in_v1_mode(idev)) {
                        psf->sf_crcount = idev->mc_qrv;
                        psf->sf_next = pmc->mca_tomb;
                        pmc->mca_tomb = psf;
                        rv = 1;
                } else
                        kfree(psf);
        }
        return rv;
}

static int ip6_mc_del_src(struct inet6_dev *idev, const struct in6_addr *pmca,
                          int sfmode, int sfcount, const struct in6_addr *psfsrc,
                          int delta)
{
        struct ifmcaddr6 *pmc;
        int     changerec = 0;
        int     i, err;

        if (!idev)
                return -ENODEV;
        read_lock_bh(&idev->lock);
        for (pmc = idev->mc_list; pmc; pmc = pmc->next) {
                if (ipv6_addr_equal(pmca, &pmc->mca_addr))
                        break;
        }
        if (!pmc) {
                /* MCA not found?? bug */
                read_unlock_bh(&idev->lock);
                return -ESRCH;
        }
        spin_lock_bh(&pmc->mca_lock);
        sf_markstate(pmc);
        if (!delta) {
                if (!pmc->mca_sfcount[sfmode]) {
                        spin_unlock_bh(&pmc->mca_lock);
                        read_unlock_bh(&idev->lock);
                        return -EINVAL;
                }
                pmc->mca_sfcount[sfmode]--;
        }
        err = 0;
        for (i = 0; i < sfcount; i++) {
                int rv = ip6_mc_del1_src(pmc, sfmode, &psfsrc[i]);

                changerec |= rv > 0;
                if (!err && rv < 0)
                        err = rv;
        }
        if (pmc->mca_sfmode == MCAST_EXCLUDE &&
            pmc->mca_sfcount[MCAST_EXCLUDE] == 0 &&
            pmc->mca_sfcount[MCAST_INCLUDE]) {
                struct ip6_sf_list *psf;

                /* filter mode change */
                pmc->mca_sfmode = MCAST_INCLUDE;
                pmc->mca_crcount = idev->mc_qrv;
                idev->mc_ifc_count = pmc->mca_crcount;
                for (psf = pmc->mca_sources; psf; psf = psf->sf_next)
                        psf->sf_crcount = 0;
                mld_ifc_event(pmc->idev);
        } else if (sf_setstate(pmc) || changerec)
                mld_ifc_event(pmc->idev);
        spin_unlock_bh(&pmc->mca_lock);
        read_unlock_bh(&idev->lock);
        return err;
}

/*
 * Add multicast single-source filter to the interface list
 */
static int ip6_mc_add1_src(struct ifmcaddr6 *pmc, int sfmode,
        const struct in6_addr *psfsrc)
{
        struct ip6_sf_list *psf, *psf_prev;

        psf_prev = NULL;
        for (psf = pmc->mca_sources; psf; psf = psf->sf_next) {
                if (ipv6_addr_equal(&psf->sf_addr, psfsrc))
                        break;
                psf_prev = psf;
        }
        if (!psf) {
                psf = kzalloc(sizeof(*psf), GFP_ATOMIC);
                if (!psf)
                        return -ENOBUFS;

                psf->sf_addr = *psfsrc;
                if (psf_prev) {
                        psf_prev->sf_next = psf;
                } else
                        pmc->mca_sources = psf;
        }
        psf->sf_count[sfmode]++;
        return 0;
}

static void sf_markstate(struct ifmcaddr6 *pmc)
{
        struct ip6_sf_list *psf;
        int mca_xcount = pmc->mca_sfcount[MCAST_EXCLUDE];

        for (psf = pmc->mca_sources; psf; psf = psf->sf_next)
                if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
                        psf->sf_oldin = mca_xcount ==
                                psf->sf_count[MCAST_EXCLUDE] &&
                                !psf->sf_count[MCAST_INCLUDE];
                } else
                        psf->sf_oldin = psf->sf_count[MCAST_INCLUDE] != 0;
}

static int sf_setstate(struct ifmcaddr6 *pmc)
{
        struct ip6_sf_list *psf, *dpsf;
        int mca_xcount = pmc->mca_sfcount[MCAST_EXCLUDE];
        int qrv = pmc->idev->mc_qrv;
        int new_in, rv;

        rv = 0;
        for (psf = pmc->mca_sources; psf; psf = psf->sf_next) {
                if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
                        new_in = mca_xcount == psf->sf_count[MCAST_EXCLUDE] &&
                                !psf->sf_count[MCAST_INCLUDE];
                } else
                        new_in = psf->sf_count[MCAST_INCLUDE] != 0;
                if (new_in) {
                        if (!psf->sf_oldin) {
                                struct ip6_sf_list *prev = NULL;

                                for (dpsf = pmc->mca_tomb; dpsf;
                                     dpsf = dpsf->sf_next) {
                                        if (ipv6_addr_equal(&dpsf->sf_addr,
                                            &psf->sf_addr))
                                                break;
                                        prev = dpsf;
                                }
                                if (dpsf) {
                                        if (prev)
                                                prev->sf_next = dpsf->sf_next;
                                        else
                                                pmc->mca_tomb = dpsf->sf_next;
                                        kfree(dpsf);
                                }
                                psf->sf_crcount = qrv;
                                rv++;
                        }
                } else if (psf->sf_oldin) {
                        psf->sf_crcount = 0;
                        /*
                         * add or update "delete" records if an active filter
                         * is now inactive
                         */
                        for (dpsf = pmc->mca_tomb; dpsf; dpsf = dpsf->sf_next)
                                if (ipv6_addr_equal(&dpsf->sf_addr,
                                    &psf->sf_addr))
                                        break;
                        if (!dpsf) {
                                dpsf = kmalloc(sizeof(*dpsf), GFP_ATOMIC);
                                if (!dpsf)
                                        continue;
                                *dpsf = *psf;
                                /* pmc->mca_lock held by callers */
                                dpsf->sf_next = pmc->mca_tomb;
                                pmc->mca_tomb = dpsf;
                        }
                        dpsf->sf_crcount = qrv;
                        rv++;
                }
        }
        return rv;
}

/*
 * Add multicast source filter list to the interface list
 */
static int ip6_mc_add_src(struct inet6_dev *idev, const struct in6_addr *pmca,
                          int sfmode, int sfcount, const struct in6_addr *psfsrc,
                          int delta)
{
        struct ifmcaddr6 *pmc;
        int     isexclude;
        int     i, err;

        if (!idev)
                return -ENODEV;
        read_lock_bh(&idev->lock);
        for (pmc = idev->mc_list; pmc; pmc = pmc->next) {
                if (ipv6_addr_equal(pmca, &pmc->mca_addr))
                        break;
        }
        if (!pmc) {
                /* MCA not found?? bug */
                read_unlock_bh(&idev->lock);
                return -ESRCH;
        }
        spin_lock_bh(&pmc->mca_lock);

        sf_markstate(pmc);
        isexclude = pmc->mca_sfmode == MCAST_EXCLUDE;
        if (!delta)
                pmc->mca_sfcount[sfmode]++;
        err = 0;
        for (i = 0; i < sfcount; i++) {
                err = ip6_mc_add1_src(pmc, sfmode, &psfsrc[i]);
                if (err)
                        break;
        }
        if (err) {
                int j;

                if (!delta)
                        pmc->mca_sfcount[sfmode]--;
                for (j = 0; j < i; j++)
                        ip6_mc_del1_src(pmc, sfmode, &psfsrc[j]);
        } else if (isexclude != (pmc->mca_sfcount[MCAST_EXCLUDE] != 0)) {
                struct ip6_sf_list *psf;

                /* filter mode change */
                if (pmc->mca_sfcount[MCAST_EXCLUDE])
                        pmc->mca_sfmode = MCAST_EXCLUDE;
                else if (pmc->mca_sfcount[MCAST_INCLUDE])
                        pmc->mca_sfmode = MCAST_INCLUDE;
                /* else no filters; keep old mode for reports */

                pmc->mca_crcount = idev->mc_qrv;
                idev->mc_ifc_count = pmc->mca_crcount;
                for (psf = pmc->mca_sources; psf; psf = psf->sf_next)
                        psf->sf_crcount = 0;
                mld_ifc_event(idev);
        } else if (sf_setstate(pmc))
                mld_ifc_event(idev);
        spin_unlock_bh(&pmc->mca_lock);
        read_unlock_bh(&idev->lock);
        return err;
}

static void ip6_mc_clear_src(struct ifmcaddr6 *pmc)
{
        struct ip6_sf_list *psf, *nextpsf;

        for (psf = pmc->mca_tomb; psf; psf = nextpsf) {
                nextpsf = psf->sf_next;
                kfree(psf);
        }
        pmc->mca_tomb = NULL;
        for (psf = pmc->mca_sources; psf; psf = nextpsf) {
                nextpsf = psf->sf_next;
                kfree(psf);
        }
        pmc->mca_sources = NULL;
        pmc->mca_sfmode = MCAST_EXCLUDE;
        pmc->mca_sfcount[MCAST_INCLUDE] = 0;
        pmc->mca_sfcount[MCAST_EXCLUDE] = 1;
}


static void igmp6_join_group(struct ifmcaddr6 *ma)
{
        unsigned long delay;

        if (ma->mca_flags & MAF_NOREPORT)
                return;

        igmp6_send(&ma->mca_addr, ma->idev->dev, ICMPV6_MGM_REPORT);

        delay = prandom_u32() % unsolicited_report_interval(ma->idev);

        spin_lock_bh(&ma->mca_lock);
        if (del_timer(&ma->mca_timer)) {
                refcount_dec(&ma->mca_refcnt);
                delay = ma->mca_timer.expires - jiffies;
        }

        if (!mod_timer(&ma->mca_timer, jiffies + delay))
                refcount_inc(&ma->mca_refcnt);
        ma->mca_flags |= MAF_TIMER_RUNNING | MAF_LAST_REPORTER;
        spin_unlock_bh(&ma->mca_lock);
}

static int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
                            struct inet6_dev *idev)
{
        int err;

        write_lock_bh(&iml->sflock);
        if (!iml->sflist) {
                /* any-source empty exclude case */
                err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode, 0, NULL, 0);
        } else {
                err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode,
                                iml->sflist->sl_count, iml->sflist->sl_addr, 0);
                sock_kfree_s(sk, iml->sflist, IP6_SFLSIZE(iml->sflist->sl_max));
                iml->sflist = NULL;
        }
        write_unlock_bh(&iml->sflock);
        return err;
}

static void igmp6_leave_group(struct ifmcaddr6 *ma)
{
        if (mld_in_v1_mode(ma->idev)) {
                if (ma->mca_flags & MAF_LAST_REPORTER)
                        igmp6_send(&ma->mca_addr, ma->idev->dev,
                                ICMPV6_MGM_REDUCTION);
        } else {
                mld_add_delrec(ma->idev, ma);
                mld_ifc_event(ma->idev);
        }
}

static void mld_gq_timer_expire(struct timer_list *t)
{
        struct inet6_dev *idev = from_timer(idev, t, mc_gq_timer);

        idev->mc_gq_running = 0;
        mld_send_report(idev, NULL);
        in6_dev_put(idev);
}

static void mld_ifc_timer_expire(struct timer_list *t)
{
        struct inet6_dev *idev = from_timer(idev, t, mc_ifc_timer);

        mld_send_cr(idev);
        if (idev->mc_ifc_count) {
                idev->mc_ifc_count--;
                if (idev->mc_ifc_count)
                        mld_ifc_start_timer(idev,
                                            unsolicited_report_interval(idev));
        }
        in6_dev_put(idev);
}

static void mld_ifc_event(struct inet6_dev *idev)
{
        if (mld_in_v1_mode(idev))
                return;
        idev->mc_ifc_count = idev->mc_qrv;
        mld_ifc_start_timer(idev, 1);
}

static void igmp6_timer_handler(struct timer_list *t)
{
        struct ifmcaddr6 *ma = from_timer(ma, t, mca_timer);

        if (mld_in_v1_mode(ma->idev))
                igmp6_send(&ma->mca_addr, ma->idev->dev, ICMPV6_MGM_REPORT);
        else
                mld_send_report(ma->idev, ma);

        spin_lock(&ma->mca_lock);
        ma->mca_flags |=  MAF_LAST_REPORTER;
        ma->mca_flags &= ~MAF_TIMER_RUNNING;
        spin_unlock(&ma->mca_lock);
        ma_put(ma);
}

/* Device changing type */

void ipv6_mc_unmap(struct inet6_dev *idev)
{
        struct ifmcaddr6 *i;

        /* Install multicast list, except for all-nodes (already installed) */

        read_lock_bh(&idev->lock);
        for (i = idev->mc_list; i; i = i->next)
                igmp6_group_dropped(i);
        read_unlock_bh(&idev->lock);
}

void ipv6_mc_remap(struct inet6_dev *idev)
{
        ipv6_mc_up(idev);
}

/* Device going down */

void ipv6_mc_down(struct inet6_dev *idev)
{
        struct ifmcaddr6 *i;

        /* Withdraw multicast list */

        read_lock_bh(&idev->lock);

        for (i = idev->mc_list; i; i = i->next)
                igmp6_group_dropped(i);

        /* Should stop timer after group drop. or we will
         * start timer again in mld_ifc_event()
         */
        mld_ifc_stop_timer(idev);
        mld_gq_stop_timer(idev);
        mld_dad_stop_timer(idev);
        read_unlock_bh(&idev->lock);
}

static void ipv6_mc_reset(struct inet6_dev *idev)
{
        idev->mc_qrv = sysctl_mld_qrv;
        idev->mc_qi = MLD_QI_DEFAULT;
        idev->mc_qri = MLD_QRI_DEFAULT;
        idev->mc_v1_seen = 0;
        idev->mc_maxdelay = unsolicited_report_interval(idev);
}

/* Device going up */

void ipv6_mc_up(struct inet6_dev *idev)
{
        struct ifmcaddr6 *i;

        /* Install multicast list, except for all-nodes (already installed) */

        read_lock_bh(&idev->lock);
        ipv6_mc_reset(idev);
        for (i = idev->mc_list; i; i = i->next) {
                mld_del_delrec(idev, i);
                igmp6_group_added(i);
        }
        read_unlock_bh(&idev->lock);
}

/* IPv6 device initialization. */

void ipv6_mc_init_dev(struct inet6_dev *idev)
{
        write_lock_bh(&idev->lock);
        spin_lock_init(&idev->mc_lock);
        idev->mc_gq_running = 0;
        timer_setup(&idev->mc_gq_timer, mld_gq_timer_expire, 0);
        idev->mc_tomb = NULL;
        idev->mc_ifc_count = 0;
        timer_setup(&idev->mc_ifc_timer, mld_ifc_timer_expire, 0);
        timer_setup(&idev->mc_dad_timer, mld_dad_timer_expire, 0);
        ipv6_mc_reset(idev);
        write_unlock_bh(&idev->lock);
}

/*
 *      Device is about to be destroyed: clean up.
 */

void ipv6_mc_destroy_dev(struct inet6_dev *idev)
{
        struct ifmcaddr6 *i;

        /* Deactivate timers */
        ipv6_mc_down(idev);
        mld_clear_delrec(idev);

        /* Delete all-nodes address. */
        /* We cannot call ipv6_dev_mc_dec() directly, our caller in
         * addrconf.c has NULL'd out dev->ip6_ptr so in6_dev_get() will
         * fail.
         */
        __ipv6_dev_mc_dec(idev, &in6addr_linklocal_allnodes);

        if (idev->cnf.forwarding)
                __ipv6_dev_mc_dec(idev, &in6addr_linklocal_allrouters);

        write_lock_bh(&idev->lock);
        while ((i = idev->mc_list) != NULL) {
                idev->mc_list = i->next;

                write_unlock_bh(&idev->lock);
                ip6_mc_clear_src(i);
                ma_put(i);
                write_lock_bh(&idev->lock);
        }
        write_unlock_bh(&idev->lock);
}

static void ipv6_mc_rejoin_groups(struct inet6_dev *idev)
{
        struct ifmcaddr6 *pmc;

        ASSERT_RTNL();

        if (mld_in_v1_mode(idev)) {
                read_lock_bh(&idev->lock);
                for (pmc = idev->mc_list; pmc; pmc = pmc->next)
                        igmp6_join_group(pmc);
                read_unlock_bh(&idev->lock);
        } else
                mld_send_report(idev, NULL);
}

static int ipv6_mc_netdev_event(struct notifier_block *this,
                                unsigned long event,
                                void *ptr)
{
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
        struct inet6_dev *idev = __in6_dev_get(dev);

        switch (event) {
        case NETDEV_RESEND_IGMP:
                if (idev)
                        ipv6_mc_rejoin_groups(idev);
                break;
        default:
                break;
        }

        return NOTIFY_DONE;
}

static struct notifier_block igmp6_netdev_notifier = {
        .notifier_call = ipv6_mc_netdev_event,
};

#ifdef CONFIG_PROC_FS
struct igmp6_mc_iter_state {
        struct seq_net_private p;
        struct net_device *dev;
        struct inet6_dev *idev;
};

#define igmp6_mc_seq_private(seq)       ((struct igmp6_mc_iter_state *)(seq)->private)

static inline struct ifmcaddr6 *igmp6_mc_get_first(struct seq_file *seq)
{
        struct ifmcaddr6 *im = NULL;
        struct igmp6_mc_iter_state *state = igmp6_mc_seq_private(seq);
        struct net *net = seq_file_net(seq);

        state->idev = NULL;
        for_each_netdev_rcu(net, state->dev) {
                struct inet6_dev *idev;
                idev = __in6_dev_get(state->dev);
                if (!idev)
                        continue;
                read_lock_bh(&idev->lock);
                im = idev->mc_list;
                if (im) {
                        state->idev = idev;
                        break;
                }
                read_unlock_bh(&idev->lock);
        }
        return im;
}

static struct ifmcaddr6 *igmp6_mc_get_next(struct seq_file *seq, struct ifmcaddr6 *im)
{
        struct igmp6_mc_iter_state *state = igmp6_mc_seq_private(seq);

        im = im->next;
        while (!im) {
                if (likely(state->idev))
                        read_unlock_bh(&state->idev->lock);

                state->dev = next_net_device_rcu(state->dev);
                if (!state->dev) {
                        state->idev = NULL;
                        break;
                }
                state->idev = __in6_dev_get(state->dev);
                if (!state->idev)
                        continue;
                read_lock_bh(&state->idev->lock);
                im = state->idev->mc_list;
        }
        return im;
}

static struct ifmcaddr6 *igmp6_mc_get_idx(struct seq_file *seq, loff_t pos)
{
        struct ifmcaddr6 *im = igmp6_mc_get_first(seq);
        if (im)
                while (pos && (im = igmp6_mc_get_next(seq, im)) != NULL)
                        --pos;
        return pos ? NULL : im;
}

static void *igmp6_mc_seq_start(struct seq_file *seq, loff_t *pos)
        __acquires(RCU)
{
        rcu_read_lock();
        return igmp6_mc_get_idx(seq, *pos);
}

static void *igmp6_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        struct ifmcaddr6 *im = igmp6_mc_get_next(seq, v);

        ++*pos;
        return im;
}

static void igmp6_mc_seq_stop(struct seq_file *seq, void *v)
        __releases(RCU)
{
        struct igmp6_mc_iter_state *state = igmp6_mc_seq_private(seq);

        if (likely(state->idev)) {
                read_unlock_bh(&state->idev->lock);
                state->idev = NULL;
        }
        state->dev = NULL;
        rcu_read_unlock();
}

static int igmp6_mc_seq_show(struct seq_file *seq, void *v)
{
        struct ifmcaddr6 *im = (struct ifmcaddr6 *)v;
        struct igmp6_mc_iter_state *state = igmp6_mc_seq_private(seq);

        seq_printf(seq,
                   "%-4d %-15s %pi6 %5d %08X %ld\n",
                   state->dev->ifindex, state->dev->name,
                   &im->mca_addr,
                   im->mca_users, im->mca_flags,
                   (im->mca_flags&MAF_TIMER_RUNNING) ?
                   jiffies_to_clock_t(im->mca_timer.expires-jiffies) : 0);
        return 0;
}

static const struct seq_operations igmp6_mc_seq_ops = {
        .start  =       igmp6_mc_seq_start,
        .next   =       igmp6_mc_seq_next,
        .stop   =       igmp6_mc_seq_stop,
        .show   =       igmp6_mc_seq_show,
};

struct igmp6_mcf_iter_state {
        struct seq_net_private p;
        struct net_device *dev;
        struct inet6_dev *idev;
        struct ifmcaddr6 *im;
};

#define igmp6_mcf_seq_private(seq)      ((struct igmp6_mcf_iter_state *)(seq)->private)

static inline struct ip6_sf_list *igmp6_mcf_get_first(struct seq_file *seq)
{
        struct ip6_sf_list *psf = NULL;
        struct ifmcaddr6 *im = NULL;
        struct igmp6_mcf_iter_state *state = igmp6_mcf_seq_private(seq);
        struct net *net = seq_file_net(seq);

        state->idev = NULL;
        state->im = NULL;
        for_each_netdev_rcu(net, state->dev) {
                struct inet6_dev *idev;
                idev = __in6_dev_get(state->dev);
                if (unlikely(idev == NULL))
                        continue;
                read_lock_bh(&idev->lock);
                im = idev->mc_list;
                if (likely(im)) {
                        spin_lock_bh(&im->mca_lock);
                        psf = im->mca_sources;
                        if (likely(psf)) {
                                state->im = im;
                                state->idev = idev;
                                break;
                        }
                        spin_unlock_bh(&im->mca_lock);
                }
                read_unlock_bh(&idev->lock);
        }
        return psf;
}

static struct ip6_sf_list *igmp6_mcf_get_next(struct seq_file *seq, struct ip6_sf_list *psf)
{
        struct igmp6_mcf_iter_state *state = igmp6_mcf_seq_private(seq);

        psf = psf->sf_next;
        while (!psf) {
                spin_unlock_bh(&state->im->mca_lock);
                state->im = state->im->next;
                while (!state->im) {
                        if (likely(state->idev))
                                read_unlock_bh(&state->idev->lock);

                        state->dev = next_net_device_rcu(state->dev);
                        if (!state->dev) {
                                state->idev = NULL;
                                goto out;
                        }
                        state->idev = __in6_dev_get(state->dev);
                        if (!state->idev)
                                continue;
                        read_lock_bh(&state->idev->lock);
                        state->im = state->idev->mc_list;
                }
                if (!state->im)
                        break;
                spin_lock_bh(&state->im->mca_lock);
                psf = state->im->mca_sources;
        }
out:
        return psf;
}

static struct ip6_sf_list *igmp6_mcf_get_idx(struct seq_file *seq, loff_t pos)
{
        struct ip6_sf_list *psf = igmp6_mcf_get_first(seq);
        if (psf)
                while (pos && (psf = igmp6_mcf_get_next(seq, psf)) != NULL)
                        --pos;
        return pos ? NULL : psf;
}

static void *igmp6_mcf_seq_start(struct seq_file *seq, loff_t *pos)
        __acquires(RCU)
{
        rcu_read_lock();
        return *pos ? igmp6_mcf_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

static void *igmp6_mcf_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        struct ip6_sf_list *psf;
        if (v == SEQ_START_TOKEN)
                psf = igmp6_mcf_get_first(seq);
        else
                psf = igmp6_mcf_get_next(seq, v);
        ++*pos;
        return psf;
}

static void igmp6_mcf_seq_stop(struct seq_file *seq, void *v)
        __releases(RCU)
{
        struct igmp6_mcf_iter_state *state = igmp6_mcf_seq_private(seq);
        if (likely(state->im)) {
                spin_unlock_bh(&state->im->mca_lock);
                state->im = NULL;
        }
        if (likely(state->idev)) {
                read_unlock_bh(&state->idev->lock);
                state->idev = NULL;
        }
        state->dev = NULL;
        rcu_read_unlock();
}

static int igmp6_mcf_seq_show(struct seq_file *seq, void *v)
{
        struct ip6_sf_list *psf = (struct ip6_sf_list *)v;
        struct igmp6_mcf_iter_state *state = igmp6_mcf_seq_private(seq);

        if (v == SEQ_START_TOKEN) {
                seq_puts(seq, "Idx Device                Multicast Address                   Source Address    INC    EXC\n");
        } else {
                seq_printf(seq,
                           "%3d %6.6s %pi6 %pi6 %6lu %6lu\n",
                           state->dev->ifindex, state->dev->name,
                           &state->im->mca_addr,
                           &psf->sf_addr,
                           psf->sf_count[MCAST_INCLUDE],
                           psf->sf_count[MCAST_EXCLUDE]);
        }
        return 0;
}

static const struct seq_operations igmp6_mcf_seq_ops = {
        .start  =       igmp6_mcf_seq_start,
        .next   =       igmp6_mcf_seq_next,
        .stop   =       igmp6_mcf_seq_stop,
        .show   =       igmp6_mcf_seq_show,
};

static int __net_init igmp6_proc_init(struct net *net)
{
        int err;

        err = -ENOMEM;
        if (!proc_create_net("igmp6", 0444, net->proc_net, &igmp6_mc_seq_ops,
                        sizeof(struct igmp6_mc_iter_state)))
                goto out;
        if (!proc_create_net("mcfilter6", 0444, net->proc_net,
                        &igmp6_mcf_seq_ops,
                        sizeof(struct igmp6_mcf_iter_state)))
                goto out_proc_net_igmp6;

        err = 0;
out:
        return err;

out_proc_net_igmp6:
        remove_proc_entry("igmp6", net->proc_net);
        goto out;
}

static void __net_exit igmp6_proc_exit(struct net *net)
{
        remove_proc_entry("mcfilter6", net->proc_net);
        remove_proc_entry("igmp6", net->proc_net);
}
#else
static inline int igmp6_proc_init(struct net *net)
{
        return 0;
}
static inline void igmp6_proc_exit(struct net *net)
{
}
#endif

static int __net_init igmp6_net_init(struct net *net)
{
        int err;

        err = inet_ctl_sock_create(&net->ipv6.igmp_sk, PF_INET6,
                                   SOCK_RAW, IPPROTO_ICMPV6, net);
        if (err < 0) {
                pr_err("Failed to initialize the IGMP6 control socket (err %d)\n",
                       err);
                goto out;
        }

        inet6_sk(net->ipv6.igmp_sk)->hop_limit = 1;

        err = inet_ctl_sock_create(&net->ipv6.mc_autojoin_sk, PF_INET6,
                                   SOCK_RAW, IPPROTO_ICMPV6, net);
        if (err < 0) {
                pr_err("Failed to initialize the IGMP6 autojoin socket (err %d)\n",
                       err);
                goto out_sock_create;
        }

        err = igmp6_proc_init(net);
        if (err)
                goto out_sock_create_autojoin;

        return 0;

out_sock_create_autojoin:
        inet_ctl_sock_destroy(net->ipv6.mc_autojoin_sk);
out_sock_create:
        inet_ctl_sock_destroy(net->ipv6.igmp_sk);
out:
        return err;
}

static void __net_exit igmp6_net_exit(struct net *net)
{
        inet_ctl_sock_destroy(net->ipv6.igmp_sk);
        inet_ctl_sock_destroy(net->ipv6.mc_autojoin_sk);
        igmp6_proc_exit(net);