/*
 *      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 <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>

/* Set to 3 to get tracing... */
#define MCAST_DEBUG 2

#if MCAST_DEBUG >= 3
#define MDBG(x) printk x
#else
#define MDBG(x)
#endif

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

static struct in6_addr mld2_all_mcr = MLD2_ALL_MCR_INIT;

/* Big mc list lock for all the sockets */
static DEFINE_SPINLOCK(ipv6_sk_mc_lock);

static void igmp6_join_group(struct ifmcaddr6 *ma);
static void igmp6_leave_group(struct ifmcaddr6 *ma);
static void igmp6_timer_handler(unsigned long data);

static void mld_gq_timer_expire(unsigned long data);
static void mld_ifc_timer_expire(unsigned long data);
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, const struct in6_addr *addr);
static void mld_clear_delrec(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);


#define IGMP6_UNSOLICITED_IVAL  (10*HZ)
#define MLD_QRV_DEFAULT         2

#define MLD_V1_SEEN(idev) (dev_net((idev)->dev)->ipv6.devconf_all->force_mld_version == 1 || \
                (idev)->cnf.force_mld_version == 1 || \
                ((idev)->mc_v1_seen && \
                time_before(jiffies, (idev)->mc_v1_seen)))

#define IPV6_MLD_MAX_MSF        64

int sysctl_mld_max_msf __read_mostly = IPV6_MLD_MAX_MSF;

/*
 *      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))

int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
{
        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;

        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 == NULL)
                return -ENOMEM;

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

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

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

        mc_lst->ifindex = dev->ifindex;
        mc_lst->sfmode = MCAST_EXCLUDE;
        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);

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

        spin_lock(&ipv6_sk_mc_lock);
        mc_lst->next = np->ipv6_mc_list;
        rcu_assign_pointer(np->ipv6_mc_list, mc_lst);
        spin_unlock(&ipv6_sk_mc_lock);

        rcu_read_unlock();

        return 0;
}

/*
 *      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);

        spin_lock(&ipv6_sk_mc_lock);
        for (lnk = &np->ipv6_mc_list;
             (mc_lst = rcu_dereference_protected(*lnk,
                        lockdep_is_held(&ipv6_sk_mc_lock))) !=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;
                        spin_unlock(&ipv6_sk_mc_lock);

                        rcu_read_lock();
                        dev = dev_get_by_index_rcu(net, mc_lst->ifindex);
                        if (dev != NULL) {
                                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);
                        rcu_read_unlock();
                        atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);
                        kfree_rcu(mc_lst, rcu);
                        return 0;
                }
        }
        spin_unlock(&ipv6_sk_mc_lock);

        return -EADDRNOTAVAIL;
}

/* 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, 0);

                if (rt) {
                        dev = rt->dst.dev;
                        dst_release(&rt->dst);
                }
        } 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);

        spin_lock(&ipv6_sk_mc_lock);
        while ((mc_lst = rcu_dereference_protected(np->ipv6_mc_list,
                                lockdep_is_held(&ipv6_sk_mc_lock))) != NULL) {
                struct net_device *dev;

                np->ipv6_mc_list = mc_lst->next;
                spin_unlock(&ipv6_sk_mc_lock);

                rcu_read_lock();
                dev = dev_get_by_index_rcu(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);
                rcu_read_unlock();

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

                spin_lock(&ipv6_sk_mc_lock);
        }
        spin_unlock(&ipv6_sk_mc_lock);
}

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 = memcmp(&psl->sl_addr[i], source,
                                sizeof(struct in6_addr));
                        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 = memcmp(&psl->sl_addr[i], source, sizeof(struct in6_addr));
                if (rv == 0)
                        break;
        }
        if (rv == 0)            /* address already there is an error */
                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)
                return 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
         * a read lock on ip6_sk_mc_lock. We have the socket 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, a read lock on
         * on ipv6_sk_mc_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;
}

int 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;
        int rv = 1;

        rcu_read_lock();
        for_each_pmc_rcu(np, mc) {
                if (ipv6_addr_equal(&mc->addr, mc_addr))
                        break;
        }
        if (!mc) {
                rcu_read_unlock();
                return 1;
        }
        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 = 0;
                if (mc->sfmode == MCAST_EXCLUDE && i < psl->sl_count)
                        rv = 0;
        }
        read_unlock(&mc->sflock);
        rcu_read_unlock();

        return rv;
}

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

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

        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_V1_SEEN(mc->idev)) {
                igmp6_join_group(mc);
                return;
        }
        /* else v2 */

        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];

        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);
        }

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

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

        spin_lock_bh(&mc->mca_lock);
        if (del_timer(&mc->mca_timer))
                atomic_dec(&mc->mca_refcnt);
done:
        ip6_mc_clear_src(mc);
        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, const struct in6_addr *pmca)
{
        struct ifmcaddr6 *pmc, *pmc_prev;
        struct ip6_sf_list *psf, *psf_next;

        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);

        if (pmc) {
                for (psf=pmc->mca_tomb; psf; psf=psf_next) {
                        psf_next = psf->sf_next;
                        kfree(psf);
                }
                in6_dev_put(pmc->idev);
                kfree(pmc);
        }
}

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);
}


/*
 *      device multicast group inc (add if not found)
 */
int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr)
{
        struct ifmcaddr6 *mc;
        struct inet6_dev *idev;

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

        if (idev == NULL)
                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, MCAST_EXCLUDE, 0,
                                NULL, 0);
                        in6_dev_put(idev);
                        return 0;
                }
        }

        /*
         *      not found: create a new one.
         */

        mc = kzalloc(sizeof(struct ifmcaddr6), GFP_ATOMIC);

        if (mc == NULL) {
                write_unlock_bh(&idev->lock);
                in6_dev_put(idev);
                return -ENOMEM;
        }

        setup_timer(&mc->mca_timer, igmp6_timer_handler, (unsigned long)mc);

        mc->mca_addr = *addr;
        mc->idev = idev; /* (reference taken) */
        mc->mca_users = 1;
        /* mca_stamp should be updated upon changes */
        mc->mca_cstamp = mc->mca_tstamp = jiffies;
        atomic_set(&mc->mca_refcnt, 2);
        spin_lock_init(&mc->mca_lock);

        /* initial mode is (EX, empty) */
        mc->mca_sfmode = MCAST_EXCLUDE;
        mc->mca_sfcount[MCAST_EXCLUDE] = 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;

        mc->next = idev->mc_list;
        idev->mc_list = mc;
        write_unlock_bh(&idev->lock);

        mld_del_delrec(idev, &mc->mca_addr);
        igmp6_group_added(mc);
        ma_put(mc);
        return 0;
}

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

        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);

                                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;

        rcu_read_lock();

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

        rcu_read_unlock();
        return err;
}

/*
 * identify MLD packets for MLD filter exceptions
 */
int ipv6_is_mld(struct sk_buff *skb, int nexthdr)
{
        struct icmp6hdr *pic;

        if (nexthdr != IPPROTO_ICMPV6)
                return 0;

        if (!pskb_may_pull(skb, sizeof(struct icmp6hdr)))
                return 0;

        pic = icmp6_hdr(skb);

        switch (pic->icmp6_type) {
        case ICMPV6_MGM_QUERY:
        case ICMPV6_MGM_REPORT:
        case ICMPV6_MGM_REDUCTION:
        case ICMPV6_MLD2_REPORT:
                return 1;
        default:
                break;
        }
        return 0;
}

/*
 *      check if the interface/address pair is valid
 */
int 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;
        int rv = 0;

        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 = 1; /* 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)
{
        int tv = net_random() % 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_ifc_start_timer(struct inet6_dev *idev, int delay)
{
        int tv = net_random() % delay;

        if (!mod_timer(&idev->mc_ifc_timer, jiffies+tv+2))
                in6_dev_hold(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)) {
                atomic_dec(&ma->mca_refcnt);
                delay = ma->mca_timer.expires - jiffies;
        }

        if (delay >= resptime) {
                if (resptime)
                        delay = net_random() % resptime;
                else
                        delay = 1;
        }
        ma->mca_timer.expires = jiffies + delay;
        if (!mod_timer(&ma->mca_timer, jiffies + delay))
                atomic_inc(&ma->mca_refcnt);
        ma->mca_flags |= MAF_TIMER_RUNNING;
}

/* mark EXCLUDE-mode sources */
static int 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])
                                continue;
                        if (ipv6_addr_equal(&srcs[i], &psf->sf_addr)) {
                                scount++;
                                break;
                        }
                }
        }
        pmc->mca_flags &= ~MAF_GSQUERY;
        if (scount == nsrcs)    /* all sources excluded */
                return 0;
        return 1;
}

static int 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 0;
        }
        pmc->mca_flags |= MAF_GSQUERY;
        return 1;
}

/* 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;

        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);

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

        idev = __in6_dev_get(skb->dev);

        if (idev == NULL)
                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 == 24) {
                int switchback;
                /* MLDv1 router present */

                /* Translate milliseconds to jiffies */
                max_delay = (ntohs(mld->mld_maxdelay)*HZ)/1000;

                switchback = (idev->mc_qrv + 1) * max_delay;
                idev->mc_v1_seen = jiffies + switchback;

                /* cancel the interface change timer */
                idev->mc_ifc_count = 0;
                if (del_timer(&idev->mc_ifc_timer))
                        __in6_dev_put(idev);
                /* clear deleted report items */
                mld_clear_delrec(idev);
        } else if (len >= 28) {
                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);
                max_delay = (MLDV2_MRC(ntohs(mlh2->mld2q_mrc))*HZ)/1000;
                if (!max_delay)
                        max_delay = 1;
                idev->mc_maxdelay = max_delay;
                if (mlh2->mld2q_qrv)
                        idev->mc_qrv = mlh2->mld2q_qrv;
                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 == NULL)
                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))
                                atomic_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 int 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 0;
                if (!((pmc->mca_flags & MAF_GSQUERY) && !psf->sf_gsresp)) {
                        if (pmc->mca_sfmode == MCAST_INCLUDE)
                                return 1;
                        /* 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 0;
        case MLD2_CHANGE_TO_INCLUDE:
                if (gdeleted || sdeleted)
                        return 0;
                return psf->sf_count[MCAST_INCLUDE] != 0;
        case MLD2_CHANGE_TO_EXCLUDE:
                if (gdeleted || sdeleted)
                        return 0;
                if (pmc->mca_sfcount[MCAST_EXCLUDE] == 0 ||
                    psf->sf_count[MCAST_INCLUDE])
                        return 0;
                return pmc->mca_sfcount[MCAST_EXCLUDE] ==
                        psf->sf_count[MCAST_EXCLUDE];
        case MLD2_ALLOW_NEW_SOURCES:
                if (gdeleted || !psf->sf_crcount)
                        return 0;
                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 0;
}

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 struct sk_buff *mld_newpack(struct net_device *dev, int size)
{
        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;
        int err;
        u8 ra[8] = { IPPROTO_ICMPV6, 0,
                     IPV6_TLV_ROUTERALERT, 2, 0, 0,
                     IPV6_TLV_PADN, 0 };

        /* we assume size > sizeof(ra) here */
        size += hlen + tlen;
        /* 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_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_nd_hdr(sk, skb, dev, saddr, &mld2_all_mcr, NEXTHDR_HOP, 0);

        memcpy(skb_put(skb, sizeof(ra)), 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 - skb->network_header) - sizeof(*pip6);
        mldlen = skb->tail - skb->transport_header;
        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, NULL, &fl6);

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

        payload_len = skb->len;

        err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, skb->dev,
                      dst_output);
out:
        if (!err) {
                ICMP6MSGOUT_INC_STATS_BH(net, idev, ICMPV6_MLD2_REPORT);
                ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS);
                IP6_UPD_PO_STATS_BH(net, idev, IPSTATS_MIB_OUTMCAST, payload_len);
        } else
                IP6_INC_STATS_BH(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)
{
        struct net_device *dev = pmc->idev->dev;
        struct mld2_report *pmr;
        struct mld2_grec *pgr;

        if (!skb)
                skb = mld_newpack(dev, dev->mtu);
        if (!skb)
                return NULL;
        pgr = (struct mld2_grec *)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)->dev ? (skb)->dev->mtu - (skb)->len : \
        skb_tailroom(skb)) : 0)

static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,
        int type, int gdeleted, int sdeleted)
{
        struct net_device *dev = pmc->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;

        if (pmc->mca_flags & MAF_NOREPORT)
                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(dev, dev->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)) {
                        psf_prev = psf;
                        continue;
                }

                /* 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(dev, dev->mtu);
                        first = 1;
                        scount = 0;
                }
                if (first) {
                        skb = add_grhead(skb, pmc, type, &pgr);
                        first = 0;
                }
                if (!skb)
                        return NULL;
                psrc = (struct in6_addr *)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) {
                        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) {
                        /* 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);
                }
        }
        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;

        if (!pmc) {
                read_lock_bh(&idev->lock);
                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);
                        spin_unlock_bh(&pmc->mca_lock);
                }
                read_unlock_bh(&idev->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);
                spin_unlock_bh(&pmc->mca_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);
                        skb = add_grec(skb, pmc, dtype, 1, 1);
                }
                if (pmc->mca_crcount) {
                        if (pmc->mca_sfmode == MCAST_EXCLUDE) {
                                type = MLD2_CHANGE_TO_INCLUDE;
                                skb = add_grec(skb, pmc, type, 1, 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);
                skb = add_grec(skb, pmc, dtype, 0, 1);  /* 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);
                        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 == NULL) {
                rcu_read_lock();
                IP6_INC_STATS(net, __in6_dev_get(dev),
                              IPSTATS_MIB_OUTDISCARDS);
                rcu_read_unlock();
                return;
        }

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

        memcpy(skb_put(skb, sizeof(ra)), ra, sizeof(ra));

        hdr = (struct mld_msg *) skb_put(skb, sizeof(struct mld_msg));
        memset(hdr, 0, 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, NULL, &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, skb, NULL, skb->dev,
                      dst_output);
out:
        if (!err) {
                ICMP6MSGOUT_INC_STATS(net, idev, type);
                ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
                IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, full_len);
        } else
                IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);

        rcu_read_unlock();
        return;

err_out:
        kfree_skb(skb);
        goto out;
}

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_V1_SEEN(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++;