linux-stable/drivers/net/vxlan/vxlan_mdb.c

// SPDX-License-Identifier: GPL-2.0-only

#include <linux/if_bridge.h>
#include <linux/in.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/rhashtable.h>
#include <linux/rhashtable-types.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <net/netlink.h>
#include <net/vxlan.h>

#include "vxlan_private.h"

struct vxlan_mdb_entry_key {
	union vxlan_addr src;
	union vxlan_addr dst;
	__be32 vni;
};

struct vxlan_mdb_entry {
	struct rhash_head rhnode;
	struct list_head remotes;
	struct vxlan_mdb_entry_key key;
	struct hlist_node mdb_node;
	struct rcu_head rcu;
};

#define VXLAN_MDB_REMOTE_F_BLOCKED	BIT(0)

struct vxlan_mdb_remote {
	struct list_head list;
	struct vxlan_rdst __rcu *rd;
	u8 flags;
	u8 filter_mode;
	u8 rt_protocol;
	struct hlist_head src_list;
	struct rcu_head rcu;
};

#define VXLAN_SGRP_F_DELETE	BIT(0)

struct vxlan_mdb_src_entry {
	struct hlist_node node;
	union vxlan_addr addr;
	u8 flags;
};

struct vxlan_mdb_dump_ctx {
	long reserved;
	long entry_idx;
	long remote_idx;
};

struct vxlan_mdb_config_src_entry {
	union vxlan_addr addr;
	struct list_head node;
};

struct vxlan_mdb_config {
	struct vxlan_dev *vxlan;
	struct vxlan_mdb_entry_key group;
	struct list_head src_list;
	union vxlan_addr remote_ip;
	u32 remote_ifindex;
	__be32 remote_vni;
	__be16 remote_port;
	u16 nlflags;
	u8 flags;
	u8 filter_mode;
	u8 rt_protocol;
};

static const struct rhashtable_params vxlan_mdb_rht_params = {
	.head_offset = offsetof(struct vxlan_mdb_entry, rhnode),
	.key_offset = offsetof(struct vxlan_mdb_entry, key),
	.key_len = sizeof(struct vxlan_mdb_entry_key),
	.automatic_shrinking = true,
};

static int __vxlan_mdb_add(const struct vxlan_mdb_config *cfg,
			   struct netlink_ext_ack *extack);
static int __vxlan_mdb_del(const struct vxlan_mdb_config *cfg,
			   struct netlink_ext_ack *extack);

static void vxlan_br_mdb_entry_fill(const struct vxlan_dev *vxlan,
				    const struct vxlan_mdb_entry *mdb_entry,
				    const struct vxlan_mdb_remote *remote,
				    struct br_mdb_entry *e)
{
	const union vxlan_addr *dst = &mdb_entry->key.dst;

	memset(e, 0, sizeof(*e));
	e->ifindex = vxlan->dev->ifindex;
	e->state = MDB_PERMANENT;

	if (remote->flags & VXLAN_MDB_REMOTE_F_BLOCKED)
		e->flags |= MDB_FLAGS_BLOCKED;

	switch (dst->sa.sa_family) {
	case AF_INET:
		e->addr.u.ip4 = dst->sin.sin_addr.s_addr;
		e->addr.proto = htons(ETH_P_IP);
		break;
#if IS_ENABLED(CONFIG_IPV6)
	case AF_INET6:
		e->addr.u.ip6 = dst->sin6.sin6_addr;
		e->addr.proto = htons(ETH_P_IPV6);
		break;
#endif
	}
}

static int vxlan_mdb_entry_info_fill_srcs(struct sk_buff *skb,
					  const struct vxlan_mdb_remote *remote)
{
	struct vxlan_mdb_src_entry *ent;
	struct nlattr *nest;

	if (hlist_empty(&remote->src_list))
		return 0;

	nest = nla_nest_start(skb, MDBA_MDB_EATTR_SRC_LIST);
	if (!nest)
		return -EMSGSIZE;

	hlist_for_each_entry(ent, &remote->src_list, node) {
		struct nlattr *nest_ent;

		nest_ent = nla_nest_start(skb, MDBA_MDB_SRCLIST_ENTRY);
		if (!nest_ent)
			goto out_cancel_err;

		if (vxlan_nla_put_addr(skb, MDBA_MDB_SRCATTR_ADDRESS,
				       &ent->addr) ||
		    nla_put_u32(skb, MDBA_MDB_SRCATTR_TIMER, 0))
			goto out_cancel_err;

		nla_nest_end(skb, nest_ent);
	}

	nla_nest_end(skb, nest);

	return 0;

out_cancel_err:
	nla_nest_cancel(skb, nest);
	return -EMSGSIZE;
}

static int vxlan_mdb_entry_info_fill(const struct vxlan_dev *vxlan,
				     struct sk_buff *skb,
				     const struct vxlan_mdb_entry *mdb_entry,
				     const struct vxlan_mdb_remote *remote)
{
	struct vxlan_rdst *rd = rtnl_dereference(remote->rd);
	struct br_mdb_entry e;
	struct nlattr *nest;

	nest = nla_nest_start_noflag(skb, MDBA_MDB_ENTRY_INFO);
	if (!nest)
		return -EMSGSIZE;

	vxlan_br_mdb_entry_fill(vxlan, mdb_entry, remote, &e);

	if (nla_put_nohdr(skb, sizeof(e), &e) ||
	    nla_put_u32(skb, MDBA_MDB_EATTR_TIMER, 0))
		goto nest_err;

	if (!vxlan_addr_any(&mdb_entry->key.src) &&
	    vxlan_nla_put_addr(skb, MDBA_MDB_EATTR_SOURCE, &mdb_entry->key.src))
		goto nest_err;

	if (nla_put_u8(skb, MDBA_MDB_EATTR_RTPROT, remote->rt_protocol) ||
	    nla_put_u8(skb, MDBA_MDB_EATTR_GROUP_MODE, remote->filter_mode) ||
	    vxlan_mdb_entry_info_fill_srcs(skb, remote) ||
	    vxlan_nla_put_addr(skb, MDBA_MDB_EATTR_DST, &rd->remote_ip))
		goto nest_err;

	if (rd->remote_port && rd->remote_port != vxlan->cfg.dst_port &&
	    nla_put_u16(skb, MDBA_MDB_EATTR_DST_PORT,
			be16_to_cpu(rd->remote_port)))
		goto nest_err;

	if (rd->remote_vni != vxlan->default_dst.remote_vni &&
	    nla_put_u32(skb, MDBA_MDB_EATTR_VNI, be32_to_cpu(rd->remote_vni)))
		goto nest_err;

	if (rd->remote_ifindex &&
	    nla_put_u32(skb, MDBA_MDB_EATTR_IFINDEX, rd->remote_ifindex))
		goto nest_err;

	if ((vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA) &&
	    mdb_entry->key.vni && nla_put_u32(skb, MDBA_MDB_EATTR_SRC_VNI,
					      be32_to_cpu(mdb_entry->key.vni)))
		goto nest_err;

	nla_nest_end(skb, nest);

	return 0;

nest_err:
	nla_nest_cancel(skb, nest);
	return -EMSGSIZE;
}

static int vxlan_mdb_entry_fill(const struct vxlan_dev *vxlan,
				struct sk_buff *skb,
				struct vxlan_mdb_dump_ctx *ctx,
				const struct vxlan_mdb_entry *mdb_entry)
{
	int remote_idx = 0, s_remote_idx = ctx->remote_idx;
	struct vxlan_mdb_remote *remote;
	struct nlattr *nest;
	int err = 0;

	nest = nla_nest_start_noflag(skb, MDBA_MDB_ENTRY);
	if (!nest)
		return -EMSGSIZE;

	list_for_each_entry(remote, &mdb_entry->remotes, list) {
		if (remote_idx < s_remote_idx)
			goto skip;

		err = vxlan_mdb_entry_info_fill(vxlan, skb, mdb_entry, remote);
		if (err)
			break;
skip:
		remote_idx++;
	}

	ctx->remote_idx = err ? remote_idx : 0;
	nla_nest_end(skb, nest);
	return err;
}

static int vxlan_mdb_fill(const struct vxlan_dev *vxlan, struct sk_buff *skb,
			  struct vxlan_mdb_dump_ctx *ctx)
{
	int entry_idx = 0, s_entry_idx = ctx->entry_idx;
	struct vxlan_mdb_entry *mdb_entry;
	struct nlattr *nest;
	int err = 0;

	nest = nla_nest_start_noflag(skb, MDBA_MDB);
	if (!nest)
		return -EMSGSIZE;

	hlist_for_each_entry(mdb_entry, &vxlan->mdb_list, mdb_node) {
		if (entry_idx < s_entry_idx)
			goto skip;

		err = vxlan_mdb_entry_fill(vxlan, skb, ctx, mdb_entry);
		if (err)
			break;
skip:
		entry_idx++;
	}

	ctx->entry_idx = err ? entry_idx : 0;
	nla_nest_end(skb, nest);
	return err;
}

int vxlan_mdb_dump(struct net_device *dev, struct sk_buff *skb,
		   struct netlink_callback *cb)
{
	struct vxlan_mdb_dump_ctx *ctx = (void *)cb->ctx;
	struct vxlan_dev *vxlan = netdev_priv(dev);
	struct br_port_msg *bpm;
	struct nlmsghdr *nlh;
	int err;

	ASSERT_RTNL();

	NL_ASSERT_DUMP_CTX_FITS(struct vxlan_mdb_dump_ctx);

	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid,
			cb->nlh->nlmsg_seq, RTM_NEWMDB, sizeof(*bpm),
			NLM_F_MULTI);
	if (!nlh)
		return -EMSGSIZE;

	bpm = nlmsg_data(nlh);
	memset(bpm, 0, sizeof(*bpm));
	bpm->family = AF_BRIDGE;
	bpm->ifindex = dev->ifindex;

	err = vxlan_mdb_fill(vxlan, skb, ctx);

	nlmsg_end(skb, nlh);

	cb->seq = vxlan->mdb_seq;
	nl_dump_check_consistent(cb, nlh);

	return err;
}

static const struct nla_policy
vxlan_mdbe_src_list_entry_pol[MDBE_SRCATTR_MAX + 1] = {
	[MDBE_SRCATTR_ADDRESS] = NLA_POLICY_RANGE(NLA_BINARY,
						  sizeof(struct in_addr),
						  sizeof(struct in6_addr)),
};

static const struct nla_policy
vxlan_mdbe_src_list_pol[MDBE_SRC_LIST_MAX + 1] = {
	[MDBE_SRC_LIST_ENTRY] = NLA_POLICY_NESTED(vxlan_mdbe_src_list_entry_pol),
};

static struct netlink_range_validation vni_range = {
	.max = VXLAN_N_VID - 1,
};

static const struct nla_policy vxlan_mdbe_attrs_pol[MDBE_ATTR_MAX + 1] = {
	[MDBE_ATTR_SOURCE] = NLA_POLICY_RANGE(NLA_BINARY,
					      sizeof(struct in_addr),
					      sizeof(struct in6_addr)),
	[MDBE_ATTR_GROUP_MODE] = NLA_POLICY_RANGE(NLA_U8, MCAST_EXCLUDE,
						  MCAST_INCLUDE),
	[MDBE_ATTR_SRC_LIST] = NLA_POLICY_NESTED(vxlan_mdbe_src_list_pol),
	[MDBE_ATTR_RTPROT] = NLA_POLICY_MIN(NLA_U8, RTPROT_STATIC),
	[MDBE_ATTR_DST] = NLA_POLICY_RANGE(NLA_BINARY,
					   sizeof(struct in_addr),
					   sizeof(struct in6_addr)),
	[MDBE_ATTR_DST_PORT] = { .type = NLA_U16 },
	[MDBE_ATTR_VNI] = NLA_POLICY_FULL_RANGE(NLA_U32, &vni_range),
	[MDBE_ATTR_IFINDEX] = NLA_POLICY_MIN(NLA_S32, 1),
	[MDBE_ATTR_SRC_VNI] = NLA_POLICY_FULL_RANGE(NLA_U32, &vni_range),
};

static bool vxlan_mdb_is_valid_source(const struct nlattr *attr, __be16 proto,
				      struct netlink_ext_ack *extack)
{
	switch (proto) {
	case htons(ETH_P_IP):
		if (nla_len(attr) != sizeof(struct in_addr)) {
			NL_SET_ERR_MSG_MOD(extack, "IPv4 invalid source address length");
			return false;
		}
		if (ipv4_is_multicast(nla_get_in_addr(attr))) {
			NL_SET_ERR_MSG_MOD(extack, "IPv4 multicast source address is not allowed");
			return false;
		}
		break;
#if IS_ENABLED(CONFIG_IPV6)
	case htons(ETH_P_IPV6): {
		struct in6_addr src;

		if (nla_len(attr) != sizeof(struct in6_addr)) {
			NL_SET_ERR_MSG_MOD(extack, "IPv6 invalid source address length");
			return false;
		}
		src = nla_get_in6_addr(attr);
		if (ipv6_addr_is_multicast(&src)) {
			NL_SET_ERR_MSG_MOD(extack, "IPv6 multicast source address is not allowed");
			return false;
		}
		break;
	}
#endif
	default:
		NL_SET_ERR_MSG_MOD(extack, "Invalid protocol used with source address");
		return false;
	}

	return true;
}

static void vxlan_mdb_config_group_set(struct vxlan_mdb_config *cfg,
				       const struct br_mdb_entry *entry,
				       const struct nlattr *source_attr)
{
	struct vxlan_mdb_entry_key *group = &cfg->group;

	switch (entry->addr.proto) {
	case htons(ETH_P_IP):
		group->dst.sa.sa_family = AF_INET;
		group->dst.sin.sin_addr.s_addr = entry->addr.u.ip4;
		break;
#if IS_ENABLED(CONFIG_IPV6)
	case htons(ETH_P_IPV6):
		group->dst.sa.sa_family = AF_INET6;
		group->dst.sin6.sin6_addr = entry->addr.u.ip6;
		break;
#endif
	}

	if (source_attr)
		vxlan_nla_get_addr(&group->src, source_attr);
}

static bool vxlan_mdb_is_star_g(const struct vxlan_mdb_entry_key *group)
{
	return !vxlan_addr_any(&group->dst) && vxlan_addr_any(&group->src);
}

static bool vxlan_mdb_is_sg(const struct vxlan_mdb_entry_key *group)
{
	return !vxlan_addr_any(&group->dst) && !vxlan_addr_any(&group->src);
}

static int vxlan_mdb_config_src_entry_init(struct vxlan_mdb_config *cfg,
					   __be16 proto,
					   const struct nlattr *src_entry,
					   struct netlink_ext_ack *extack)
{
	struct nlattr *tb[MDBE_SRCATTR_MAX + 1];
	struct vxlan_mdb_config_src_entry *src;
	int err;

	err = nla_parse_nested(tb, MDBE_SRCATTR_MAX, src_entry,
			       vxlan_mdbe_src_list_entry_pol, extack);
	if (err)
		return err;

	if (NL_REQ_ATTR_CHECK(extack, src_entry, tb, MDBE_SRCATTR_ADDRESS))
		return -EINVAL;

	if (!vxlan_mdb_is_valid_source(tb[MDBE_SRCATTR_ADDRESS], proto,
				       extack))
		return -EINVAL;

	src = kzalloc(sizeof(*src), GFP_KERNEL);
	if (!src)
		return -ENOMEM;

	err = vxlan_nla_get_addr(&src->addr, tb[MDBE_SRCATTR_ADDRESS]);
	if (err)
		goto err_free_src;

	list_add_tail(&src->node, &cfg->src_list);

	return 0;

err_free_src:
	kfree(src);
	return err;
}

static void
vxlan_mdb_config_src_entry_fini(struct vxlan_mdb_config_src_entry *src)
{
	list_del(&src->node);
	kfree(src);
}

static int vxlan_mdb_config_src_list_init(struct vxlan_mdb_config *cfg,
					  __be16 proto,
					  const struct nlattr *src_list,
					  struct netlink_ext_ack *extack)
{
	struct vxlan_mdb_config_src_entry *src, *tmp;
	struct nlattr *src_entry;
	int rem, err;

	nla_for_each_nested(src_entry, src_list, rem) {
		err = vxlan_mdb_config_src_entry_init(cfg, proto, src_entry,
						      extack);
		if (err)
			goto err_src_entry_init;
	}

	return 0;

err_src_entry_init:
	list_for_each_entry_safe_reverse(src, tmp, &cfg->src_list, node)
		vxlan_mdb_config_src_entry_fini(src);
	return err;
}

static void vxlan_mdb_config_src_list_fini(struct vxlan_mdb_config *cfg)
{
	struct vxlan_mdb_config_src_entry *src, *tmp;

	list_for_each_entry_safe_reverse(src, tmp, &cfg->src_list, node)
		vxlan_mdb_config_src_entry_fini(src);
}

static int vxlan_mdb_config_attrs_init(struct vxlan_mdb_config *cfg,
				       const struct br_mdb_entry *entry,
				       const struct nlattr *set_attrs,
				       struct netlink_ext_ack *extack)
{
	struct nlattr *mdbe_attrs[MDBE_ATTR_MAX + 1];
	int err;

	err = nla_parse_nested(mdbe_attrs, MDBE_ATTR_MAX, set_attrs,
			       vxlan_mdbe_attrs_pol, extack);
	if (err)
		return err;

	if (NL_REQ_ATTR_CHECK(extack, set_attrs, mdbe_attrs, MDBE_ATTR_DST)) {
		NL_SET_ERR_MSG_MOD(extack, "Missing remote destination IP address");
		return -EINVAL;
	}

	if (mdbe_attrs[MDBE_ATTR_SOURCE] &&
	    !vxlan_mdb_is_valid_source(mdbe_attrs[MDBE_ATTR_SOURCE],
				       entry->addr.proto, extack))
		return -EINVAL;

	vxlan_mdb_config_group_set(cfg, entry, mdbe_attrs[MDBE_ATTR_SOURCE]);

	/* rtnetlink code only validates that IPv4 group address is
	 * multicast.
	 */
	if (!vxlan_addr_is_multicast(&cfg->group.dst) &&
	    !vxlan_addr_any(&cfg->group.dst)) {
		NL_SET_ERR_MSG_MOD(extack, "Group address is not multicast");
		return -EINVAL;
	}

	if (vxlan_addr_any(&cfg->group.dst) &&
	    mdbe_attrs[MDBE_ATTR_SOURCE]) {
		NL_SET_ERR_MSG_MOD(extack, "Source cannot be specified for the all-zeros entry");
		return -EINVAL;
	}

	if (vxlan_mdb_is_sg(&cfg->group))
		cfg->filter_mode = MCAST_INCLUDE;

	if (mdbe_attrs[MDBE_ATTR_GROUP_MODE]) {
		if (!vxlan_mdb_is_star_g(&cfg->group)) {
			NL_SET_ERR_MSG_MOD(extack, "Filter mode can only be set for (*, G) entries");
			return -EINVAL;
		}
		cfg->filter_mode = nla_get_u8(mdbe_attrs[MDBE_ATTR_GROUP_MODE]);
	}

	if (mdbe_attrs[MDBE_ATTR_SRC_LIST]) {
		if (!vxlan_mdb_is_star_g(&cfg->group)) {
			NL_SET_ERR_MSG_MOD(extack, "Source list can only be set for (*, G) entries");
			return -EINVAL;
		}
		if (!mdbe_attrs[MDBE_ATTR_GROUP_MODE]) {
			NL_SET_ERR_MSG_MOD(extack, "Source list cannot be set without filter mode");
			return -EINVAL;
		}
		err = vxlan_mdb_config_src_list_init(cfg, entry->addr.proto,
						     mdbe_attrs[MDBE_ATTR_SRC_LIST],
						     extack);
		if (err)
			return err;
	}

	if (vxlan_mdb_is_star_g(&cfg->group) && list_empty(&cfg->src_list) &&
	    cfg->filter_mode == MCAST_INCLUDE) {
		NL_SET_ERR_MSG_MOD(extack, "Cannot add (*, G) INCLUDE with an empty source list");
		return -EINVAL;
	}

	if (mdbe_attrs[MDBE_ATTR_RTPROT])
		cfg->rt_protocol = nla_get_u8(mdbe_attrs[MDBE_ATTR_RTPROT]);

	err = vxlan_nla_get_addr(&cfg->remote_ip, mdbe_attrs[MDBE_ATTR_DST]);
	if (err) {
		NL_SET_ERR_MSG_MOD(extack, "Invalid remote destination address");
		goto err_src_list_fini;
	}

	if (mdbe_attrs[MDBE_ATTR_DST_PORT])
		cfg->remote_port =
			cpu_to_be16(nla_get_u16(mdbe_attrs[MDBE_ATTR_DST_PORT]));

	if (mdbe_attrs[MDBE_ATTR_VNI])
		cfg->remote_vni =
			cpu_to_be32(nla_get_u32(mdbe_attrs[MDBE_ATTR_VNI]));

	if (mdbe_attrs[MDBE_ATTR_IFINDEX]) {
		cfg->remote_ifindex =
			nla_get_s32(mdbe_attrs[MDBE_ATTR_IFINDEX]);
		if (!__dev_get_by_index(cfg->vxlan->net, cfg->remote_ifindex)) {
			NL_SET_ERR_MSG_MOD(extack, "Outgoing interface not found");
			err = -EINVAL;
			goto err_src_list_fini;
		}
	}

	if (mdbe_attrs[MDBE_ATTR_SRC_VNI])
		cfg->group.vni =
			cpu_to_be32(nla_get_u32(mdbe_attrs[MDBE_ATTR_SRC_VNI]));

	return 0;

err_src_list_fini:
	vxlan_mdb_config_src_list_fini(cfg);
	return err;
}

static int vxlan_mdb_config_init(struct vxlan_mdb_config *cfg,
				 struct net_device *dev, struct nlattr *tb[],
				 u16 nlmsg_flags,
				 struct netlink_ext_ack *extack)
{
	struct br_mdb_entry *entry = nla_data(tb[MDBA_SET_ENTRY]);
	struct vxlan_dev *vxlan = netdev_priv(dev);

	memset(cfg, 0, sizeof(*cfg));
	cfg->vxlan = vxlan;
	cfg->group.vni = vxlan->default_dst.remote_vni;
	INIT_LIST_HEAD(&cfg->src_list);
	cfg->nlflags = nlmsg_flags;
	cfg->filter_mode = MCAST_EXCLUDE;
	cfg->rt_protocol = RTPROT_STATIC;
	cfg->remote_vni = vxlan->default_dst.remote_vni;
	cfg->remote_port = vxlan->cfg.dst_port;

	if (entry->ifindex != dev->ifindex) {
		NL_SET_ERR_MSG_MOD(extack, "Port net device must be the VXLAN net device");
		return -EINVAL;
	}

	/* State is not part of the entry key and can be ignored on deletion
	 * requests.
	 */
	if ((nlmsg_flags & (NLM_F_CREATE | NLM_F_REPLACE)) &&
	    entry->state != MDB_PERMANENT) {
		NL_SET_ERR_MSG_MOD(extack, "MDB entry must be permanent");
		return -EINVAL;
	}

	if (entry->flags) {
		NL_SET_ERR_MSG_MOD(extack, "Invalid MDB entry flags");
		return -EINVAL;
	}

	if (entry->vid) {
		NL_SET_ERR_MSG_MOD(extack, "VID must not be specified");
		return -EINVAL;
	}

	if (entry->addr.proto != htons(ETH_P_IP) &&
	    entry->addr.proto != htons(ETH_P_IPV6)) {
		NL_SET_ERR_MSG_MOD(extack, "Group address must be an IPv4 / IPv6 address");
		return -EINVAL;
	}

	if (NL_REQ_ATTR_CHECK(extack, NULL, tb, MDBA_SET_ENTRY_ATTRS)) {
		NL_SET_ERR_MSG_MOD(extack, "Missing MDBA_SET_ENTRY_ATTRS attribute");
		return -EINVAL;
	}

	return vxlan_mdb_config_attrs_init(cfg, entry, tb[MDBA_SET_ENTRY_ATTRS],
					   extack);
}

static void vxlan_mdb_config_fini(struct vxlan_mdb_config *cfg)
{
	vxlan_mdb_config_src_list_fini(cfg);
}

static struct vxlan_mdb_entry *
vxlan_mdb_entry_lookup(struct vxlan_dev *vxlan,
		       const struct vxlan_mdb_entry_key *group)
{
	return rhashtable_lookup_fast(&vxlan->mdb_tbl, group,
				      vxlan_mdb_rht_params);
}

static struct vxlan_mdb_remote *
vxlan_mdb_remote_lookup(const struct vxlan_mdb_entry *mdb_entry,
			const union vxlan_addr *addr)
{
	struct vxlan_mdb_remote *remote;

	list_for_each_entry(remote, &mdb_entry->remotes, list) {
		struct vxlan_rdst *rd = rtnl_dereference(remote->rd);

		if (vxlan_addr_equal(addr, &rd->remote_ip))
			return remote;
	}

	return NULL;
}

static void vxlan_mdb_rdst_free(struct rcu_head *head)
{
	struct vxlan_rdst *rd = container_of(head, struct vxlan_rdst, rcu);

	dst_cache_destroy(&rd->dst_cache);
	kfree(rd);
}

static int vxlan_mdb_remote_rdst_init(const struct vxlan_mdb_config *cfg,
				      struct vxlan_mdb_remote *remote)
{
	struct vxlan_rdst *rd;
	int err;

	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
	if (!rd)
		return -ENOMEM;

	err = dst_cache_init(&rd->dst_cache, GFP_KERNEL);
	if (err)
		goto err_free_rdst;

	rd->remote_ip = cfg->remote_ip;
	rd->remote_port = cfg->remote_port;
	rd->remote_vni = cfg->remote_vni;
	rd->remote_ifindex = cfg->remote_ifindex;
	rcu_assign_pointer(remote->rd, rd);

	return 0;

err_free_rdst:
	kfree(rd);
	return err;
}

static void vxlan_mdb_remote_rdst_fini(struct vxlan_rdst *rd)
{
	call_rcu(&rd->rcu, vxlan_mdb_rdst_free);
}

static int vxlan_mdb_remote_init(const struct vxlan_mdb_config *cfg,
				 struct vxlan_mdb_remote *remote)
{
	int err;

	err = vxlan_mdb_remote_rdst_init(cfg, remote);
	if (err)
		return err;

	remote->flags = cfg->flags;
	remote->filter_mode = cfg->filter_mode;
	remote->rt_protocol = cfg->rt_protocol;
	INIT_HLIST_HEAD(&remote->src_list);

	return 0;
}

static void vxlan_mdb_remote_fini(struct vxlan_dev *vxlan,
				  struct vxlan_mdb_remote *remote)
{
	WARN_ON_ONCE(!hlist_empty(&remote->src_list));
	vxlan_mdb_remote_rdst_fini(rtnl_dereference(remote->rd));
}

static struct vxlan_mdb_src_entry *
vxlan_mdb_remote_src_entry_lookup(const struct vxlan_mdb_remote *remote,
				  const union vxlan_addr *addr)
{
	struct vxlan_mdb_src_entry *ent;

	hlist_for_each_entry(ent, &remote->src_list, node) {
		if (vxlan_addr_equal(&ent->addr, addr))
			return ent;
	}

	return NULL;
}

static struct vxlan_mdb_src_entry *
vxlan_mdb_remote_src_entry_add(struct vxlan_mdb_remote *remote,
			       const union vxlan_addr *addr)
{
	struct vxlan_mdb_src_entry *ent;

	ent = kzalloc(sizeof(*ent), GFP_KERNEL);
	if (!ent)
		return NULL;

	ent->addr = *addr;
	hlist_add_head(&ent->node, &remote->src_list);

	return ent;
}

static void
vxlan_mdb_remote_src_entry_del(struct vxlan_mdb_src_entry *ent)
{
	hlist_del(&ent->node);
	kfree(ent);
}

static int
vxlan_mdb_remote_src_fwd_add(const struct vxlan_mdb_config *cfg,
			     const union vxlan_addr *addr,
			     struct netlink_ext_ack *extack)
{
	struct vxlan_mdb_config sg_cfg;

	memset(&sg_cfg, 0, sizeof(sg_cfg));
	sg_cfg.vxlan = cfg->vxlan;
	sg_cfg.group.src = *addr;
	sg_cfg.group.dst = cfg->group.dst;
	sg_cfg.group.vni = cfg->group.vni;
	INIT_LIST_HEAD(&sg_cfg.src_list);
	sg_cfg.remote_ip = cfg->remote_ip;
	sg_cfg.remote_ifindex = cfg->remote_ifindex;
	sg_cfg.remote_vni = cfg->remote_vni;
	sg_cfg.remote_port = cfg->remote_port;
	sg_cfg.nlflags = cfg->nlflags;
	sg_cfg.filter_mode = MCAST_INCLUDE;
	if (cfg->filter_mode == MCAST_EXCLUDE)
		sg_cfg.flags = VXLAN_MDB_REMOTE_F_BLOCKED;
	sg_cfg.rt_protocol = cfg->rt_protocol;

	return __vxlan_mdb_add(&sg_cfg, extack);
}

static void
vxlan_mdb_remote_src_fwd_del(struct vxlan_dev *vxlan,
			     const struct vxlan_mdb_entry_key *group,
			     const struct vxlan_mdb_remote *remote,
			     const union vxlan_addr *addr)
{
	struct vxlan_rdst *rd = rtnl_dereference(remote->rd);
	struct vxlan_mdb_config sg_cfg;

	memset(&sg_cfg, 0, sizeof(sg_cfg));
	sg_cfg.vxlan = vxlan;
	sg_cfg.group.src = *addr;
	sg_cfg.group.dst = group->dst;
	sg_cfg.group.vni = group->vni;
	INIT_LIST_HEAD(&sg_cfg.src_list);
	sg_cfg.remote_ip = rd->remote_ip;

	__vxlan_mdb_del(&sg_cfg, NULL);
}

static int
vxlan_mdb_remote_src_add(const struct vxlan_mdb_config *cfg,
			 struct vxlan_mdb_remote *remote,
			 const struct vxlan_mdb_config_src_entry *src,
			 struct netlink_ext_ack *extack)
{
	struct vxlan_mdb_src_entry *ent;
	int err;

	ent = vxlan_mdb_remote_src_entry_lookup(remote, &src->addr);
	if (!ent) {
		ent = vxlan_mdb_remote_src_entry_add(remote, &src->addr);
		if (!ent)
			return -ENOMEM;
	} else if (!(cfg->nlflags & NLM_F_REPLACE)) {
		NL_SET_ERR_MSG_MOD(extack, "Source entry already exists");
		return -EEXIST;
	}

	err = vxlan_mdb_remote_src_fwd_add(cfg, &ent->addr, extack);
	if (err)
		goto err_src_del;

	/* Clear flags in case source entry was marked for deletion as part of
	 * replace flow.
	 */
	ent->flags = 0;

	return 0;

err_src_del:
	vxlan_mdb_remote_src_entry_del(ent);
	return err;
}

static void vxlan_mdb_remote_src_del(struct vxlan_dev *vxlan,
				     const struct vxlan_mdb_entry_key *group,
				     const struct vxlan_mdb_remote *remote,
				     struct vxlan_mdb_src_entry *ent)
{
	vxlan_mdb_remote_src_fwd_del(vxlan, group, remote, &ent->addr);
	vxlan_mdb_remote_src_entry_del(ent);
}

static int vxlan_mdb_remote_srcs_add(const struct vxlan_mdb_config *cfg,
				     struct vxlan_mdb_remote *remote,
				     struct netlink_ext_ack *extack)
{
	struct vxlan_mdb_config_src_entry *src;
	struct vxlan_mdb_src_entry *ent;
	struct hlist_node *tmp;
	int err;

	list_for_each_entry(src, &cfg->src_list, node) {
		err = vxlan_mdb_remote_src_add(cfg, remote, src, extack);
		if (err)
			goto err_src_del;
	}

	return 0;

err_src_del:
	hlist_for_each_entry_safe(ent, tmp, &remote->src_list, node)
		vxlan_mdb_remote_src_del(cfg->vxlan, &cfg->group, remote, ent);
	return err;
}

static void vxlan_mdb_remote_srcs_del(struct vxlan_dev *vxlan,
				      const struct vxlan_mdb_entry_key *group,
				      struct vxlan_mdb_remote *remote)
{
	struct vxlan_mdb_src_entry *ent;
	struct hlist_node *tmp;

	hlist_for_each_entry_safe(ent, tmp, &remote->src_list, node)
		vxlan_mdb_remote_src_del(vxlan, group, remote, ent);
}

static size_t
vxlan_mdb_nlmsg_src_list_size(const struct vxlan_mdb_entry_key *group,
			      const struct vxlan_mdb_remote *remote)
{
	struct vxlan_mdb_src_entry *ent;
	size_t nlmsg_size;

	if (hlist_empty(&remote->src_list))
		return 0;

	/* MDBA_MDB_EATTR_SRC_LIST */
	nlmsg_size = nla_total_size(0);

	hlist_for_each_entry(ent, &remote->src_list, node) {
			      /* MDBA_MDB_SRCLIST_ENTRY */
		nlmsg_size += nla_total_size(0) +
			      /* MDBA_MDB_SRCATTR_ADDRESS */
			      nla_total_size(vxlan_addr_size(&group->dst)) +
			      /* MDBA_MDB_SRCATTR_TIMER */
			      nla_total_size(sizeof(u8));
	}

	return nlmsg_size;
}

static size_t vxlan_mdb_nlmsg_size(const struct vxlan_dev *vxlan,
				   const struct vxlan_mdb_entry *mdb_entry,
				   const struct vxlan_mdb_remote *remote)
{
	const struct vxlan_mdb_entry_key *group = &mdb_entry->key;
	struct vxlan_rdst *rd = rtnl_dereference(remote->rd);
	size_t nlmsg_size;

	nlmsg_size = NLMSG_ALIGN(sizeof(struct br_port_msg)) +
		     /* MDBA_MDB */
		     nla_total_size(0) +
		     /* MDBA_MDB_ENTRY */
		     nla_total_size(0) +
		     /* MDBA_MDB_ENTRY_INFO */
		     nla_total_size(sizeof(struct br_mdb_entry)) +
		     /* MDBA_MDB_EATTR_TIMER */
		     nla_total_size(sizeof(u32));
	/* MDBA_MDB_EATTR_SOURCE */
	if (vxlan_mdb_is_sg(group))
		nlmsg_size += nla_total_size(vxlan_addr_size(&group->dst));
	/* MDBA_MDB_EATTR_RTPROT */
	nlmsg_size += nla_total_size(sizeof(u8));
	/* MDBA_MDB_EATTR_SRC_LIST */
	nlmsg_size += vxlan_mdb_nlmsg_src_list_size(group, remote);
	/* MDBA_MDB_EATTR_GROUP_MODE */
	nlmsg_size += nla_total_size(sizeof(u8));
	/* MDBA_MDB_EATTR_DST */
	nlmsg_size += nla_total_size(vxlan_addr_size(&rd->remote_ip));
	/* MDBA_MDB_EATTR_DST_PORT */
	if (rd->remote_port && rd->remote_port != vxlan->cfg.dst_port)
		nlmsg_size += nla_total_size(sizeof(u16));
	/* MDBA_MDB_EATTR_VNI */
	if (rd->remote_vni != vxlan->default_dst.remote_vni)
		nlmsg_size += nla_total_size(sizeof(u32));
	/* MDBA_MDB_EATTR_IFINDEX */
	if (rd->remote_ifindex)
		nlmsg_size += nla_total_size(sizeof(u32));
	/* MDBA_MDB_EATTR_SRC_VNI */
	if ((vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA) && group->vni)
		nlmsg_size += nla_total_size(sizeof(u32));

	return nlmsg_size;
}

static int vxlan_mdb_nlmsg_fill(const struct vxlan_dev *vxlan,
				struct sk_buff *skb,
				const struct vxlan_mdb_entry *mdb_entry,
				const struct vxlan_mdb_remote *remote,
				int type)
{
	struct nlattr *mdb_nest, *mdb_entry_nest;
	struct br_port_msg *bpm;
	struct nlmsghdr *nlh;

	nlh = nlmsg_put(skb, 0, 0, type, sizeof(*bpm), 0);
	if (!nlh)
		return -EMSGSIZE;

	bpm = nlmsg_data(nlh);
	memset(bpm, 0, sizeof(*bpm));
	bpm->family  = AF_BRIDGE;
	bpm->ifindex = vxlan->dev->ifindex;

	mdb_nest = nla_nest_start_noflag(skb, MDBA_MDB);
	if (!mdb_nest)
		goto cancel;
	mdb_entry_nest = nla_nest_start_noflag(skb, MDBA_MDB_ENTRY);
	if (!mdb_entry_nest)
		goto cancel;

	if (vxlan_mdb_entry_info_fill(vxlan, skb, mdb_entry, remote))
		goto cancel;

	nla_nest_end(skb, mdb_entry_nest);
	nla_nest_end(skb, mdb_nest);
	nlmsg_end(skb, nlh);

	return 0;

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

static void vxlan_mdb_remote_notify(const struct vxlan_dev *vxlan,
				    const struct vxlan_mdb_entry *mdb_entry,
				    const struct vxlan_mdb_remote *remote,
				    int type)
{
	struct net *net = dev_net(vxlan->dev);
	struct sk_buff *skb;
	int err = -ENOBUFS;

	skb = nlmsg_new(vxlan_mdb_nlmsg_size(vxlan, mdb_entry, remote),
			GFP_KERNEL);
	if (!skb)
		goto errout;

	err = vxlan_mdb_nlmsg_fill(vxlan, skb, mdb_entry, remote, type);
	if (err) {
		kfree_skb(skb);
		goto errout;
	}

	rtnl_notify(skb, net, 0, RTNLGRP_MDB, NULL, GFP_KERNEL);
	return;
errout:
	rtnl_set_sk_err(net, RTNLGRP_MDB, err);
}

static int
vxlan_mdb_remote_srcs_replace(const struct vxlan_mdb_config *cfg,
			      const struct vxlan_mdb_entry *mdb_entry,
			      struct vxlan_mdb_remote *remote,
			      struct netlink_ext_ack *extack)
{
	struct vxlan_dev *vxlan = cfg->vxlan;
	struct vxlan_mdb_src_entry *ent;
	struct hlist_node *tmp;
	int err;

	hlist_for_each_entry(ent, &remote->src_list, node)
		ent->flags |= VXLAN_SGRP_F_DELETE;

	err = vxlan_mdb_remote_srcs_add(cfg, remote, extack);
	if (err)
		goto err_clear_delete;

	hlist_for_each_entry_safe(ent, tmp, &remote->src_list, node) {
		if (ent->flags & VXLAN_SGRP_F_DELETE)
			vxlan_mdb_remote_src_del(vxlan, &mdb_entry->key, remote,
						 ent);
	}

	return 0;

err_clear_delete:
	hlist_for_each_entry(ent, &remote->src_list, node)
		ent->flags &= ~VXLAN_SGRP_F_DELETE;
	return err;
}

static int vxlan_mdb_remote_replace(const struct vxlan_mdb_config *cfg,
				    const struct vxlan_mdb_entry *mdb_entry,
				    struct vxlan_mdb_remote *remote,
				    struct netlink_ext_ack *extack)
{
	struct vxlan_rdst *new_rd, *old_rd = rtnl_dereference(remote->rd);
	struct vxlan_dev *vxlan = cfg->vxlan;
	int err;

	err = vxlan_mdb_remote_rdst_init(cfg, remote);
	if (err)
		return err;
	new_rd = rtnl_dereference(remote->rd);

	err = vxlan_mdb_remote_srcs_replace(cfg, mdb_entry, remote, extack);
	if (err)
		goto err_rdst_reset;

	WRITE_ONCE(remote->flags, cfg->flags);
	WRITE_ONCE(remote->filter_mode, cfg->filter_mode);
	remote->rt_protocol = cfg->rt_protocol;
	vxlan_mdb_remote_notify(vxlan, mdb_entry, remote, RTM_NEWMDB);

	vxlan_mdb_remote_rdst_fini(old_rd);

	return 0;

err_rdst_reset:
	rcu_assign_pointer(remote->rd, old_rd);
	vxlan_mdb_remote_rdst_fini(new_rd);
	return err;
}

static int vxlan_mdb_remote_add(const struct vxlan_mdb_config *cfg,
				struct vxlan_mdb_entry *mdb_entry,
				struct netlink_ext_ack *extack)
{
	struct vxlan_mdb_remote *remote;
	int err;

	remote = vxlan_mdb_remote_lookup(mdb_entry, &cfg->remote_ip);
	if (remote) {
		if (!(cfg->nlflags & NLM_F_REPLACE)) {
			NL_SET_ERR_MSG_MOD(extack, "Replace not specified and MDB remote entry already exists");
			return -EEXIST;
		}
		return vxlan_mdb_remote_replace(cfg, mdb_entry, remote, extack);
	}

	if (!(cfg->nlflags & NLM_F_CREATE)) {
		NL_SET_ERR_MSG_MOD(extack, "Create not specified and entry does not exist");
		return -ENOENT;
	}

	remote = kzalloc(sizeof(*remote), GFP_KERNEL);
	if (!remote)
		return -ENOMEM;

	err = vxlan_mdb_remote_init(cfg, remote);
	if (err) {
		NL_SET_ERR_MSG_MOD(extack, "Failed to initialize remote MDB entry");
		goto err_free_remote;
	}

	err = vxlan_mdb_remote_srcs_add(cfg, remote, extack);
	if (err)
		goto err_remote_fini;

	list_add_rcu(&remote->list, &mdb_entry->remotes);
	vxlan_mdb_remote_notify(cfg->vxlan, mdb_entry, remote, RTM_NEWMDB);

	return 0;

err_remote_fini:
	vxlan_mdb_remote_fini(cfg->vxlan, remote);
err_free_remote:
	kfree(remote);
	return err;
}

static void vxlan_mdb_remote_del(struct vxlan_dev *vxlan,
				 struct vxlan_mdb_entry *mdb_entry,
				 struct vxlan_mdb_remote *remote)
{
	vxlan_mdb_remote_notify(vxlan, mdb_entry, remote, RTM_DELMDB);
	list_del_rcu(&remote->list);
	vxlan_mdb_remote_srcs_del(vxlan, &mdb_entry->key, remote);
	vxlan_mdb_remote_fini(vxlan, remote);
	kfree_rcu(remote, rcu);
}

static struct vxlan_mdb_entry *
vxlan_mdb_entry_get(struct vxlan_dev *vxlan,
		    const struct vxlan_mdb_entry_key *group)
{
	struct vxlan_mdb_entry *mdb_entry;
	int err;

	mdb_entry = vxlan_mdb_entry_lookup(vxlan, group);
	if (mdb_entry)
		return mdb_entry;

	mdb_entry = kzalloc(sizeof(*mdb_entry), GFP_KERNEL);
	if (!mdb_entry)
		return ERR_PTR(-ENOMEM);

	INIT_LIST_HEAD(&mdb_entry->remotes);
	memcpy(&mdb_entry->key, group, sizeof(mdb_entry->key));
	hlist_add_head(&mdb_entry->mdb_node, &vxlan->mdb_list);

	err = rhashtable_lookup_insert_fast(&vxlan->mdb_tbl,
					    &mdb_entry->rhnode,
					    vxlan_mdb_rht_params);
	if (err)
		goto err_free_entry;

	if (hlist_is_singular_node(&mdb_entry->mdb_node, &vxlan->mdb_list))
		vxlan->cfg.flags |= VXLAN_F_MDB;

	return mdb_entry;

err_free_entry:
	hlist_del(&mdb_entry->mdb_node);
	kfree(mdb_entry);
	return ERR_PTR(err);
}

static void vxlan_mdb_entry_put(struct vxlan_dev *vxlan,
				struct vxlan_mdb_entry *mdb_entry)
{
	if (!list_empty(&mdb_entry->remotes))
		return;

	if (hlist_is_singular_node(&mdb_entry->mdb_node, &vxlan->mdb_list))
		vxlan->cfg.flags &= ~VXLAN_F_MDB;

	rhashtable_remove_fast(&vxlan->mdb_tbl, &mdb_entry->rhnode,
			       vxlan_mdb_rht_params);
	hlist_del(&mdb_entry->mdb_node);
	kfree_rcu(mdb_entry, rcu);
}

static int __vxlan_mdb_add(const struct vxlan_mdb_config *cfg,
			   struct netlink_ext_ack *extack)
{
	struct vxlan_dev *vxlan = cfg->vxlan;
	struct vxlan_mdb_entry *mdb_entry;
	int err;

	mdb_entry = vxlan_mdb_entry_get(vxlan, &cfg->group);
	if (IS_ERR(mdb_entry))
		return PTR_ERR(mdb_entry);

	err = vxlan_mdb_remote_add(cfg, mdb_entry, extack);
	if (err)
		goto err_entry_put;

	vxlan->mdb_seq++;

	return 0;

err_entry_put:
	vxlan_mdb_entry_put(vxlan, mdb_entry);
	return err;
}

static int __vxlan_mdb_del(const struct vxlan_mdb_config *cfg,
			   struct netlink_ext_ack *extack)
{
	struct vxlan_dev *vxlan = cfg->vxlan;
	struct vxlan_mdb_entry *mdb_entry;
	struct vxlan_mdb_remote *remote;

	mdb_entry = vxlan_mdb_entry_lookup(vxlan, &cfg->group);
	if (!mdb_entry) {
		NL_SET_ERR_MSG_MOD(extack, "Did not find MDB entry");
		return -ENOENT;
	}

	remote = vxlan_mdb_remote_lookup(mdb_entry, &cfg->remote_ip);
	if (!remote) {
		NL_SET_ERR_MSG_MOD(extack, "Did not find MDB remote entry");
		return -ENOENT;
	}

	vxlan_mdb_remote_del(vxlan, mdb_entry, remote);
	vxlan_mdb_entry_put(vxlan, mdb_entry);

	vxlan->mdb_seq++;

	return 0;
}

int vxlan_mdb_add(struct net_device *dev, struct nlattr *tb[], u16 nlmsg_flags,
		  struct netlink_ext_ack *extack)
{
	struct vxlan_mdb_config cfg;
	int err;

	ASSERT_RTNL();

	err = vxlan_mdb_config_init(&cfg, dev, tb, nlmsg_flags, extack);
	if (err)
		return err;

	err = __vxlan_mdb_add(&cfg, extack);

	vxlan_mdb_config_fini(&cfg);
	return err;
}

int vxlan_mdb_del(struct net_device *dev, struct nlattr *tb[],
		  struct netlink_ext_ack *extack)
{
	struct vxlan_mdb_config cfg;
	int err;

	ASSERT_RTNL();

	err = vxlan_mdb_config_init(&cfg, dev, tb, 0, extack);
	if (err)
		return err;

	err = __vxlan_mdb_del(&cfg, extack);

	vxlan_mdb_config_fini(&cfg);
	return err;
}

struct vxlan_mdb_entry *vxlan_mdb_entry_skb_get(struct vxlan_dev *vxlan,
						struct sk_buff *skb,
						__be32 src_vni)
{
	struct vxlan_mdb_entry *mdb_entry;
	struct vxlan_mdb_entry_key group;

	if (!is_multicast_ether_addr(eth_hdr(skb)->h_dest) ||
	    is_broadcast_ether_addr(eth_hdr(skb)->h_dest))
		return NULL;

	/* When not in collect metadata mode, 'src_vni' is zero, but MDB
	 * entries are stored with the VNI of the VXLAN device.
	 */
	if (!(vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA))
		src_vni = vxlan->default_dst.remote_vni;

	memset(&group, 0, sizeof(group));
	group.vni = src_vni;

	switch (skb->protocol) {
	case htons(ETH_P_IP):
		if (!pskb_may_pull(skb, sizeof(struct iphdr)))
			return NULL;
		group.dst.sa.sa_family = AF_INET;
		group.dst.sin.sin_addr.s_addr = ip_hdr(skb)->daddr;
		group.src.sa.sa_family = AF_INET;
		group.src.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
		break;
#if IS_ENABLED(CONFIG_IPV6)
	case htons(ETH_P_IPV6):
		if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
			return NULL;
		group.dst.sa.sa_family = AF_INET6;
		group.dst.sin6.sin6_addr = ipv6_hdr(skb)->daddr;
		group.src.sa.sa_family = AF_INET6;
		group.src.sin6.sin6_addr = ipv6_hdr(skb)->saddr;
		break;
#endif
	default:
		return NULL;
	}

	mdb_entry = vxlan_mdb_entry_lookup(vxlan, &group);
	if (mdb_entry)
		return mdb_entry;

	memset(&group.src, 0, sizeof(group.src));
	mdb_entry = vxlan_mdb_entry_lookup(vxlan, &group);
	if (mdb_entry)
		return mdb_entry;

	/* No (S, G) or (*, G) found. Look up the all-zeros entry, but only if
	 * the destination IP address is not link-local multicast since we want
	 * to transmit such traffic together with broadcast and unknown unicast
	 * traffic.
	 */
	switch (skb->protocol) {
	case htons(ETH_P_IP):
		if (ipv4_is_local_multicast(group.dst.sin.sin_addr.s_addr))
			return NULL;
		group.dst.sin.sin_addr.s_addr = 0;
		break;
#if IS_ENABLED(CONFIG_IPV6)
	case htons(ETH_P_IPV6):
		if (ipv6_addr_type(&group.dst.sin6.sin6_addr) &
		    IPV6_ADDR_LINKLOCAL)
			return NULL;
		memset(&group.dst.sin6.sin6_addr, 0,
		       sizeof(group.dst.sin6.sin6_addr));
		break;
#endif
	default:
		return NULL;
	}

	return vxlan_mdb_entry_lookup(vxlan, &group);
}

netdev_tx_t vxlan_mdb_xmit(struct vxlan_dev *vxlan,
			   const struct vxlan_mdb_entry *mdb_entry,
			   struct sk_buff *skb)
{
	struct vxlan_mdb_remote *remote, *fremote = NULL;
	__be32 src_vni = mdb_entry->key.vni;

	list_for_each_entry_rcu(remote, &mdb_entry->remotes, list) {
		struct sk_buff *skb1;

		if ((vxlan_mdb_is_star_g(&mdb_entry->key) &&
		     READ_ONCE(remote->filter_mode) == MCAST_INCLUDE) ||
		    (READ_ONCE(remote->flags) & VXLAN_MDB_REMOTE_F_BLOCKED))
			continue;

		if (!fremote) {
			fremote = remote;
			continue;
		}

		skb1 = skb_clone(skb, GFP_ATOMIC);
		if (skb1)
			vxlan_xmit_one(skb1, vxlan->dev, src_vni,
				       rcu_dereference(remote->rd), false);
	}

	if (fremote)
		vxlan_xmit_one(skb, vxlan->dev, src_vni,
			       rcu_dereference(fremote->rd), false);
	else
		kfree_skb(skb);

	return NETDEV_TX_OK;
}

static void vxlan_mdb_check_empty(void *ptr, void *arg)
{
	WARN_ON_ONCE(1);
}

static void vxlan_mdb_remotes_flush(struct vxlan_dev *vxlan,
				    struct vxlan_mdb_entry *mdb_entry)
{
	struct vxlan_mdb_remote *remote, *tmp;

	list_for_each_entry_safe(remote, tmp, &mdb_entry->remotes, list)
		vxlan_mdb_remote_del(vxlan, mdb_entry, remote);
}

static void vxlan_mdb_entries_flush(struct vxlan_dev *vxlan)
{
	struct vxlan_mdb_entry *mdb_entry;
	struct hlist_node *tmp;

	/* The removal of an entry cannot trigger the removal of another entry
	 * since entries are always added to the head of the list.
	 */
	hlist_for_each_entry_safe(mdb_entry, tmp, &vxlan->mdb_list, mdb_node) {
		vxlan_mdb_remotes_flush(vxlan, mdb_entry);
		vxlan_mdb_entry_put(vxlan, mdb_entry);
	}
}

int vxlan_mdb_init(struct vxlan_dev *vxlan)
{
	int err;

	err = rhashtable_init(&vxlan->mdb_tbl, &vxlan_mdb_rht_params);
	if (err)
		return err;

	INIT_HLIST_HEAD(&vxlan->mdb_list);

	return 0;
}

void vxlan_mdb_fini(struct vxlan_dev *vxlan)
{
	vxlan_mdb_entries_flush(vxlan);
	WARN_ON_ONCE(vxlan->cfg.flags & VXLAN_F_MDB);
	rhashtable_free_and_destroy(&vxlan->mdb_tbl, vxlan_mdb_check_empty,
				    NULL);
}