/* Linux multicast routing support
 * Common logic shared by IPv4 [ipmr] and IPv6 [ip6mr] implementation
 */

#include <linux/rhashtable.h>
#include <linux/mroute_base.h>

/* Sets everything common except 'dev', since that is done under locking */
void vif_device_init(struct vif_device *v,
                     struct net_device *dev,
                     unsigned long rate_limit,
                     unsigned char threshold,
                     unsigned short flags,
                     unsigned short get_iflink_mask)
{
        RCU_INIT_POINTER(v->dev, NULL);
        v->bytes_in = 0;
        v->bytes_out = 0;
        v->pkt_in = 0;
        v->pkt_out = 0;
        v->rate_limit = rate_limit;
        v->flags = flags;
        v->threshold = threshold;
        if (v->flags & get_iflink_mask)
                v->link = dev_get_iflink(dev);
        else
                v->link = dev->ifindex;
}
EXPORT_SYMBOL(vif_device_init);

struct mr_table *
mr_table_alloc(struct net *net, u32 id,
               struct mr_table_ops *ops,
               void (*expire_func)(struct timer_list *t),
               void (*table_set)(struct mr_table *mrt,
                                 struct net *net))
{
        struct mr_table *mrt;
        int err;

        mrt = kzalloc_obj(*mrt);
        if (!mrt)
                return ERR_PTR(-ENOMEM);
        mrt->id = id;
        write_pnet(&mrt->net, net);

        mrt->ops = *ops;
        err = rhltable_init(&mrt->mfc_hash, mrt->ops.rht_params);
        if (err) {
                kfree(mrt);
                return ERR_PTR(err);
        }
        INIT_LIST_HEAD(&mrt->mfc_cache_list);
        INIT_LIST_HEAD(&mrt->mfc_unres_queue);

        timer_setup(&mrt->ipmr_expire_timer, expire_func, 0);

        mrt->mroute_reg_vif_num = -1;
        table_set(mrt, net);
        return mrt;
}
EXPORT_SYMBOL(mr_table_alloc);

void *mr_mfc_find_parent(struct mr_table *mrt, void *hasharg, int parent)
{
        struct rhlist_head *tmp, *list;
        struct mr_mfc *c;

        list = rhltable_lookup(&mrt->mfc_hash, hasharg, *mrt->ops.rht_params);
        rhl_for_each_entry_rcu(c, tmp, list, mnode)
                if (parent == -1 || parent == c->mfc_parent)
                        return c;

        return NULL;
}
EXPORT_SYMBOL(mr_mfc_find_parent);

void *mr_mfc_find_any_parent(struct mr_table *mrt, int vifi)
{
        struct rhlist_head *tmp, *list;
        struct mr_mfc *c;

        list = rhltable_lookup(&mrt->mfc_hash, mrt->ops.cmparg_any,
                               *mrt->ops.rht_params);
        rhl_for_each_entry_rcu(c, tmp, list, mnode)
                if (c->mfc_un.res.ttls[vifi] < 255)
                        return c;

        return NULL;
}
EXPORT_SYMBOL(mr_mfc_find_any_parent);

void *mr_mfc_find_any(struct mr_table *mrt, int vifi, void *hasharg)
{
        struct rhlist_head *tmp, *list;
        struct mr_mfc *c, *proxy;

        list = rhltable_lookup(&mrt->mfc_hash, hasharg, *mrt->ops.rht_params);
        rhl_for_each_entry_rcu(c, tmp, list, mnode) {
                if (c->mfc_un.res.ttls[vifi] < 255)
                        return c;

                /* It's ok if the vifi is part of the static tree */
                proxy = mr_mfc_find_any_parent(mrt, c->mfc_parent);
                if (proxy && proxy->mfc_un.res.ttls[vifi] < 255)
                        return c;
        }

        return mr_mfc_find_any_parent(mrt, vifi);
}
EXPORT_SYMBOL(mr_mfc_find_any);

#ifdef CONFIG_PROC_FS
void *mr_vif_seq_idx(struct net *net, struct mr_vif_iter *iter, loff_t pos)
{
        struct mr_table *mrt = iter->mrt;

        for (iter->ct = 0; iter->ct < mrt->maxvif; ++iter->ct) {
                if (!VIF_EXISTS(mrt, iter->ct))
                        continue;
                if (pos-- == 0)
                        return &mrt->vif_table[iter->ct];
        }
        return NULL;
}
EXPORT_SYMBOL(mr_vif_seq_idx);

void *mr_vif_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        struct mr_vif_iter *iter = seq->private;
        struct net *net = seq_file_net(seq);
        struct mr_table *mrt = iter->mrt;

        ++*pos;
        if (v == SEQ_START_TOKEN)
                return mr_vif_seq_idx(net, iter, 0);

        while (++iter->ct < mrt->maxvif) {
                if (!VIF_EXISTS(mrt, iter->ct))
                        continue;
                return &mrt->vif_table[iter->ct];
        }
        return NULL;
}
EXPORT_SYMBOL(mr_vif_seq_next);

void *mr_mfc_seq_idx(struct net *net,
                     struct mr_mfc_iter *it, loff_t pos)
{
        struct mr_table *mrt = it->mrt;
        struct mr_mfc *mfc;

        rcu_read_lock();
        it->cache = &mrt->mfc_cache_list;
        list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
                if (pos-- == 0)
                        return mfc;
        rcu_read_unlock();

        spin_lock_bh(it->lock);
        it->cache = &mrt->mfc_unres_queue;
        list_for_each_entry(mfc, it->cache, list)
                if (pos-- == 0)
                        return mfc;
        spin_unlock_bh(it->lock);

        it->cache = NULL;
        return NULL;
}
EXPORT_SYMBOL(mr_mfc_seq_idx);

void *mr_mfc_seq_next(struct seq_file *seq, void *v,
                      loff_t *pos)
{
        struct mr_mfc_iter *it = seq->private;
        struct net *net = seq_file_net(seq);
        struct mr_table *mrt = it->mrt;
        struct mr_mfc *c = v;

        ++*pos;

        if (v == SEQ_START_TOKEN)
                return mr_mfc_seq_idx(net, seq->private, 0);

        if (c->list.next != it->cache)
                return list_entry(c->list.next, struct mr_mfc, list);

        if (it->cache == &mrt->mfc_unres_queue)
                goto end_of_list;

        /* exhausted cache_array, show unresolved */
        rcu_read_unlock();
        it->cache = &mrt->mfc_unres_queue;

        spin_lock_bh(it->lock);
        if (!list_empty(it->cache))
                return list_first_entry(it->cache, struct mr_mfc, list);

end_of_list:
        spin_unlock_bh(it->lock);
        it->cache = NULL;

        return NULL;
}
EXPORT_SYMBOL(mr_mfc_seq_next);
#endif

int mr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
                   struct mr_mfc *c, struct rtmsg *rtm)
{
        struct net_device *vif_dev;
        struct rta_mfc_stats mfcs;
        struct nlattr *mp_attr;
        struct rtnexthop *nhp;
        unsigned long lastuse;
        int ct;

        /* If cache is unresolved, don't try to parse IIF and OIF */
        if (c->mfc_parent >= MAXVIFS) {
                rtm->rtm_flags |= RTNH_F_UNRESOLVED;
                return -ENOENT;
        }

        rcu_read_lock();
        vif_dev = rcu_dereference(mrt->vif_table[c->mfc_parent].dev);
        if (vif_dev && nla_put_u32(skb, RTA_IIF, vif_dev->ifindex) < 0) {
                rcu_read_unlock();
                return -EMSGSIZE;
        }
        rcu_read_unlock();

        if (c->mfc_flags & MFC_OFFLOAD)
                rtm->rtm_flags |= RTNH_F_OFFLOAD;

        mp_attr = nla_nest_start_noflag(skb, RTA_MULTIPATH);
        if (!mp_attr)
                return -EMSGSIZE;

        rcu_read_lock();
        for (ct = c->mfc_un.res.minvif; ct < c->mfc_un.res.maxvif; ct++) {
                struct vif_device *vif = &mrt->vif_table[ct];

                vif_dev = rcu_dereference(vif->dev);
                if (vif_dev && c->mfc_un.res.ttls[ct] < 255) {

                        nhp = nla_reserve_nohdr(skb, sizeof(*nhp));
                        if (!nhp) {
                                rcu_read_unlock();
                                nla_nest_cancel(skb, mp_attr);
                                return -EMSGSIZE;
                        }

                        nhp->rtnh_flags = 0;
                        nhp->rtnh_hops = c->mfc_un.res.ttls[ct];
                        nhp->rtnh_ifindex = vif_dev->ifindex;
                        nhp->rtnh_len = sizeof(*nhp);
                }
        }
        rcu_read_unlock();

        nla_nest_end(skb, mp_attr);

        lastuse = READ_ONCE(c->mfc_un.res.lastuse);
        lastuse = time_after_eq(jiffies, lastuse) ? jiffies - lastuse : 0;

        mfcs.mfcs_packets = atomic_long_read(&c->mfc_un.res.pkt);
        mfcs.mfcs_bytes = atomic_long_read(&c->mfc_un.res.bytes);
        mfcs.mfcs_wrong_if = atomic_long_read(&c->mfc_un.res.wrong_if);
        if (nla_put_64bit(skb, RTA_MFC_STATS, sizeof(mfcs), &mfcs, RTA_PAD) ||
            nla_put_u64_64bit(skb, RTA_EXPIRES, jiffies_to_clock_t(lastuse),
                              RTA_PAD))
                return -EMSGSIZE;

        rtm->rtm_type = RTN_MULTICAST;
        return 1;
}
EXPORT_SYMBOL(mr_fill_mroute);

static bool mr_mfc_uses_dev(const struct mr_table *mrt,
                            const struct mr_mfc *c,
                            const struct net_device *dev)
{
        int ct;

        for (ct = c->mfc_un.res.minvif; ct < c->mfc_un.res.maxvif; ct++) {
                const struct net_device *vif_dev;
                const struct vif_device *vif;

                vif = &mrt->vif_table[ct];
                vif_dev = rcu_access_pointer(vif->dev);
                if (vif_dev && c->mfc_un.res.ttls[ct] < 255 &&
                    vif_dev == dev)
                        return true;
        }
        return false;
}

int mr_table_dump(struct mr_table *mrt, struct sk_buff *skb,
                  struct netlink_callback *cb,
                  int (*fill)(struct mr_table *mrt, struct sk_buff *skb,
                              u32 portid, u32 seq, struct mr_mfc *c,
                              int cmd, int flags),
                  spinlock_t *lock, struct fib_dump_filter *filter)
{
        unsigned int e = 0, s_e = cb->args[1];
        unsigned int flags = NLM_F_MULTI;
        struct mr_mfc *mfc;
        int err;

        if (filter->filter_set)
                flags |= NLM_F_DUMP_FILTERED;

        list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list,
                                lockdep_rtnl_is_held()) {
                if (e < s_e)
                        goto next_entry;
                if (filter->dev &&
                    !mr_mfc_uses_dev(mrt, mfc, filter->dev))
                        goto next_entry;

                err = fill(mrt, skb, NETLINK_CB(cb->skb).portid,
                           cb->nlh->nlmsg_seq, mfc, RTM_NEWROUTE, flags);
                if (err < 0)
                        goto out;
next_entry:
                e++;
        }

        spin_lock_bh(lock);
        list_for_each_entry(mfc, &mrt->mfc_unres_queue, list) {
                if (e < s_e)
                        goto next_entry2;

                err = fill(mrt, skb, NETLINK_CB(cb->skb).portid,
                           cb->nlh->nlmsg_seq, mfc, RTM_NEWROUTE, flags);
                if (err < 0) {
                        spin_unlock_bh(lock);
                        goto out;
                }
next_entry2:
                e++;
        }
        spin_unlock_bh(lock);
        err = 0;
out:
        cb->args[1] = e;
        return err;
}
EXPORT_SYMBOL(mr_table_dump);

int mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb,
                     struct mr_table *(*iter)(struct net *net,
                                              struct mr_table *mrt),
                     int (*fill)(struct mr_table *mrt,
                                 struct sk_buff *skb,
                                 u32 portid, u32 seq, struct mr_mfc *c,
                                 int cmd, int flags),
                     spinlock_t *lock, struct fib_dump_filter *filter)
{
        unsigned int t = 0, s_t = cb->args[0];
        struct net *net = sock_net(skb->sk);
        struct mr_table *mrt;
        int err;

        /* multicast does not track protocol or have route type other
         * than RTN_MULTICAST
         */
        if (filter->filter_set) {
                if (filter->protocol || filter->flags ||
                    (filter->rt_type && filter->rt_type != RTN_MULTICAST))
                        return skb->len;
        }

        rcu_read_lock();
        for (mrt = iter(net, NULL); mrt; mrt = iter(net, mrt)) {
                if (t < s_t)
                        goto next_table;

                err = mr_table_dump(mrt, skb, cb, fill, lock, filter);
                if (err < 0)
                        break;
                cb->args[1] = 0;
next_table:
                t++;
        }
        rcu_read_unlock();

        cb->args[0] = t;

        return skb->len;
}
EXPORT_SYMBOL(mr_rtm_dumproute);

int mr_dump(struct net *net, struct notifier_block *nb, unsigned short family,
            int (*rules_dump)(struct net *net,
                              struct notifier_block *nb,
                              struct netlink_ext_ack *extack),
            struct mr_table *(*mr_iter)(struct net *net,
                                        struct mr_table *mrt),
            struct netlink_ext_ack *extack)
{
        struct mr_table *mrt;
        int err;

        err = rules_dump(net, nb, extack);
        if (err)
                return err;

        for (mrt = mr_iter(net, NULL); mrt; mrt = mr_iter(net, mrt)) {
                struct vif_device *v = &mrt->vif_table[0];
                struct net_device *vif_dev;
                struct mr_mfc *mfc;
                int vifi;

                /* Notifiy on table VIF entries */
                rcu_read_lock();
                for (vifi = 0; vifi < mrt->maxvif; vifi++, v++) {
                        vif_dev = rcu_dereference(v->dev);
                        if (!vif_dev)
                                continue;

                        err = mr_call_vif_notifier(nb, family,
                                                   FIB_EVENT_VIF_ADD, v,
                                                   vif_dev, vifi,
                                                   mrt->id, extack);
                        if (err)
                                break;
                }
                rcu_read_unlock();

                if (err)
                        return err;

                /* Notify on table MFC entries */
                list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list) {
                        err = mr_call_mfc_notifier(nb, family,
                                                   FIB_EVENT_ENTRY_ADD,
                                                   mfc, mrt->id, extack);
                        if (err)
                                return err;
                }
        }

        return 0;
}
EXPORT_SYMBOL(mr_dump);