// SPDX-License-Identifier: GPL-2.0-only
/*
 * VXLAN: Virtual eXtensible Local Area Network
 *
 * Copyright (c) 2012-2013 Vyatta Inc.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/udp.h>
#include <linux/igmp.h>
#include <linux/if_ether.h>
#include <linux/ethtool.h>
#include <net/arp.h>
#include <net/ndisc.h>
#include <net/ipv6_stubs.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/rtnetlink.h>
#include <net/inet_ecn.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/tun_proto.h>
#include <net/vxlan.h>
#include <net/nexthop.h>

#if IS_ENABLED(CONFIG_IPV6)
#include <net/ip6_tunnel.h>
#include <net/ip6_checksum.h>
#endif

#define VXLAN_VERSION   "0.1"

#define PORT_HASH_BITS  8
#define PORT_HASH_SIZE  (1<<PORT_HASH_BITS)
#define FDB_AGE_DEFAULT 300 /* 5 min */
#define FDB_AGE_INTERVAL (10 * HZ)      /* rescan interval */

/* UDP port for VXLAN traffic.
 * The IANA assigned port is 4789, but the Linux default is 8472
 * for compatibility with early adopters.
 */
static unsigned short vxlan_port __read_mostly = 8472;
module_param_named(udp_port, vxlan_port, ushort, 0444);
MODULE_PARM_DESC(udp_port, "Destination UDP port");

static bool log_ecn_error = true;
module_param(log_ecn_error, bool, 0644);
MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");

static unsigned int vxlan_net_id;
static struct rtnl_link_ops vxlan_link_ops;

static const u8 all_zeros_mac[ETH_ALEN + 2];

static int vxlan_sock_add(struct vxlan_dev *vxlan);

static void vxlan_vs_del_dev(struct vxlan_dev *vxlan);

/* per-network namespace private data for this module */
struct vxlan_net {
        struct list_head  vxlan_list;
        struct hlist_head sock_list[PORT_HASH_SIZE];
        spinlock_t        sock_lock;
        struct notifier_block nexthop_notifier_block;
};

/* Forwarding table entry */
struct vxlan_fdb {
        struct hlist_node hlist;        /* linked list of entries */
        struct rcu_head   rcu;
        unsigned long     updated;      /* jiffies */
        unsigned long     used;
        struct list_head  remotes;
        u8                eth_addr[ETH_ALEN];
        u16               state;        /* see ndm_state */
        __be32            vni;
        u16               flags;        /* see ndm_flags and below */
        struct list_head  nh_list;
        struct nexthop __rcu *nh;
        struct vxlan_dev  __rcu *vdev;
};

#define NTF_VXLAN_ADDED_BY_USER 0x100

/* salt for hash table */
static u32 vxlan_salt __read_mostly;

static inline bool vxlan_collect_metadata(struct vxlan_sock *vs)
{
        return vs->flags & VXLAN_F_COLLECT_METADATA ||
               ip_tunnel_collect_metadata();
}

#if IS_ENABLED(CONFIG_IPV6)
static inline
bool vxlan_addr_equal(const union vxlan_addr *a, const union vxlan_addr *b)
{
        if (a->sa.sa_family != b->sa.sa_family)
                return false;
        if (a->sa.sa_family == AF_INET6)
                return ipv6_addr_equal(&a->sin6.sin6_addr, &b->sin6.sin6_addr);
        else
                return a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr;
}

static int vxlan_nla_get_addr(union vxlan_addr *ip, struct nlattr *nla)
{
        if (nla_len(nla) >= sizeof(struct in6_addr)) {
                ip->sin6.sin6_addr = nla_get_in6_addr(nla);
                ip->sa.sa_family = AF_INET6;
                return 0;
        } else if (nla_len(nla) >= sizeof(__be32)) {
                ip->sin.sin_addr.s_addr = nla_get_in_addr(nla);
                ip->sa.sa_family = AF_INET;
                return 0;
        } else {
                return -EAFNOSUPPORT;
        }
}

static int vxlan_nla_put_addr(struct sk_buff *skb, int attr,
                              const union vxlan_addr *ip)
{
        if (ip->sa.sa_family == AF_INET6)
                return nla_put_in6_addr(skb, attr, &ip->sin6.sin6_addr);
        else
                return nla_put_in_addr(skb, attr, ip->sin.sin_addr.s_addr);
}

#else /* !CONFIG_IPV6 */

static inline
bool vxlan_addr_equal(const union vxlan_addr *a, const union vxlan_addr *b)
{
        return a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr;
}

static int vxlan_nla_get_addr(union vxlan_addr *ip, struct nlattr *nla)
{
        if (nla_len(nla) >= sizeof(struct in6_addr)) {
                return -EAFNOSUPPORT;
        } else if (nla_len(nla) >= sizeof(__be32)) {
                ip->sin.sin_addr.s_addr = nla_get_in_addr(nla);
                ip->sa.sa_family = AF_INET;
                return 0;
        } else {
                return -EAFNOSUPPORT;
        }
}

static int vxlan_nla_put_addr(struct sk_buff *skb, int attr,
                              const union vxlan_addr *ip)
{
        return nla_put_in_addr(skb, attr, ip->sin.sin_addr.s_addr);
}
#endif

/* Virtual Network hash table head */
static inline struct hlist_head *vni_head(struct vxlan_sock *vs, __be32 vni)
{
        return &vs->vni_list[hash_32((__force u32)vni, VNI_HASH_BITS)];
}

/* Socket hash table head */
static inline struct hlist_head *vs_head(struct net *net, __be16 port)
{
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);

        return &vn->sock_list[hash_32(ntohs(port), PORT_HASH_BITS)];
}

/* First remote destination for a forwarding entry.
 * Guaranteed to be non-NULL because remotes are never deleted.
 */
static inline struct vxlan_rdst *first_remote_rcu(struct vxlan_fdb *fdb)
{
        if (rcu_access_pointer(fdb->nh))
                return NULL;
        return list_entry_rcu(fdb->remotes.next, struct vxlan_rdst, list);
}

static inline struct vxlan_rdst *first_remote_rtnl(struct vxlan_fdb *fdb)
{
        if (rcu_access_pointer(fdb->nh))
                return NULL;
        return list_first_entry(&fdb->remotes, struct vxlan_rdst, list);
}

/* Find VXLAN socket based on network namespace, address family, UDP port,
 * enabled unshareable flags and socket device binding (see l3mdev with
 * non-default VRF).
 */
static struct vxlan_sock *vxlan_find_sock(struct net *net, sa_family_t family,
                                          __be16 port, u32 flags, int ifindex)
{
        struct vxlan_sock *vs;

        flags &= VXLAN_F_RCV_FLAGS;

        hlist_for_each_entry_rcu(vs, vs_head(net, port), hlist) {
                if (inet_sk(vs->sock->sk)->inet_sport == port &&
                    vxlan_get_sk_family(vs) == family &&
                    vs->flags == flags &&
                    vs->sock->sk->sk_bound_dev_if == ifindex)
                        return vs;
        }
        return NULL;
}

static struct vxlan_dev *vxlan_vs_find_vni(struct vxlan_sock *vs, int ifindex,
                                           __be32 vni)
{
        struct vxlan_dev_node *node;

        /* For flow based devices, map all packets to VNI 0 */
        if (vs->flags & VXLAN_F_COLLECT_METADATA)
                vni = 0;

        hlist_for_each_entry_rcu(node, vni_head(vs, vni), hlist) {
                if (node->vxlan->default_dst.remote_vni != vni)
                        continue;

                if (IS_ENABLED(CONFIG_IPV6)) {
                        const struct vxlan_config *cfg = &node->vxlan->cfg;

                        if ((cfg->flags & VXLAN_F_IPV6_LINKLOCAL) &&
                            cfg->remote_ifindex != ifindex)
                                continue;
                }

                return node->vxlan;
        }

        return NULL;
}

/* Look up VNI in a per net namespace table */
static struct vxlan_dev *vxlan_find_vni(struct net *net, int ifindex,
                                        __be32 vni, sa_family_t family,
                                        __be16 port, u32 flags)
{
        struct vxlan_sock *vs;

        vs = vxlan_find_sock(net, family, port, flags, ifindex);
        if (!vs)
                return NULL;

        return vxlan_vs_find_vni(vs, ifindex, vni);
}

/* Fill in neighbour message in skbuff. */
static int vxlan_fdb_info(struct sk_buff *skb, struct vxlan_dev *vxlan,
                          const struct vxlan_fdb *fdb,
                          u32 portid, u32 seq, int type, unsigned int flags,
                          const struct vxlan_rdst *rdst)
{
        unsigned long now = jiffies;
        struct nda_cacheinfo ci;
        bool send_ip, send_eth;
        struct nlmsghdr *nlh;
        struct nexthop *nh;
        struct ndmsg *ndm;
        int nh_family;
        u32 nh_id;

        nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
        if (nlh == NULL)
                return -EMSGSIZE;

        ndm = nlmsg_data(nlh);
        memset(ndm, 0, sizeof(*ndm));

        send_eth = send_ip = true;

        rcu_read_lock();
        nh = rcu_dereference(fdb->nh);
        if (nh) {
                nh_family = nexthop_get_family(nh);
                nh_id = nh->id;
        }
        rcu_read_unlock();

        if (type == RTM_GETNEIGH) {
                if (rdst) {
                        send_ip = !vxlan_addr_any(&rdst->remote_ip);
                        ndm->ndm_family = send_ip ? rdst->remote_ip.sa.sa_family : AF_INET;
                } else if (nh) {
                        ndm->ndm_family = nh_family;
                }
                send_eth = !is_zero_ether_addr(fdb->eth_addr);
        } else
                ndm->ndm_family = AF_BRIDGE;
        ndm->ndm_state = fdb->state;
        ndm->ndm_ifindex = vxlan->dev->ifindex;
        ndm->ndm_flags = fdb->flags;
        if (rdst && rdst->offloaded)
                ndm->ndm_flags |= NTF_OFFLOADED;
        ndm->ndm_type = RTN_UNICAST;

        if (!net_eq(dev_net(vxlan->dev), vxlan->net) &&
            nla_put_s32(skb, NDA_LINK_NETNSID,
                        peernet2id(dev_net(vxlan->dev), vxlan->net)))
                goto nla_put_failure;

        if (send_eth && nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->eth_addr))
                goto nla_put_failure;
        if (nh) {
                if (nla_put_u32(skb, NDA_NH_ID, nh_id))
                        goto nla_put_failure;
        } else if (rdst) {
                if (send_ip && vxlan_nla_put_addr(skb, NDA_DST,
                                                  &rdst->remote_ip))
                        goto nla_put_failure;

                if (rdst->remote_port &&
                    rdst->remote_port != vxlan->cfg.dst_port &&
                    nla_put_be16(skb, NDA_PORT, rdst->remote_port))
                        goto nla_put_failure;
                if (rdst->remote_vni != vxlan->default_dst.remote_vni &&
                    nla_put_u32(skb, NDA_VNI, be32_to_cpu(rdst->remote_vni)))
                        goto nla_put_failure;
                if (rdst->remote_ifindex &&
                    nla_put_u32(skb, NDA_IFINDEX, rdst->remote_ifindex))
                        goto nla_put_failure;
        }

        if ((vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA) && fdb->vni &&
            nla_put_u32(skb, NDA_SRC_VNI,
                        be32_to_cpu(fdb->vni)))
                goto nla_put_failure;

        ci.ndm_used      = jiffies_to_clock_t(now - fdb->used);
        ci.ndm_confirmed = 0;
        ci.ndm_updated   = jiffies_to_clock_t(now - fdb->updated);
        ci.ndm_refcnt    = 0;

        if (nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
                goto nla_put_failure;

        nlmsg_end(skb, nlh);
        return 0;

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

static inline size_t vxlan_nlmsg_size(void)
{
        return NLMSG_ALIGN(sizeof(struct ndmsg))
                + nla_total_size(ETH_ALEN) /* NDA_LLADDR */
                + nla_total_size(sizeof(struct in6_addr)) /* NDA_DST */
                + nla_total_size(sizeof(__be16)) /* NDA_PORT */
                + nla_total_size(sizeof(__be32)) /* NDA_VNI */
                + nla_total_size(sizeof(__u32)) /* NDA_IFINDEX */
                + nla_total_size(sizeof(__s32)) /* NDA_LINK_NETNSID */
                + nla_total_size(sizeof(struct nda_cacheinfo));
}

static void __vxlan_fdb_notify(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
                               struct vxlan_rdst *rd, int type)
{
        struct net *net = dev_net(vxlan->dev);
        struct sk_buff *skb;
        int err = -ENOBUFS;

        skb = nlmsg_new(vxlan_nlmsg_size(), GFP_ATOMIC);
        if (skb == NULL)
                goto errout;

        err = vxlan_fdb_info(skb, vxlan, fdb, 0, 0, type, 0, rd);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in vxlan_nlmsg_size() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }

        rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
        return;
errout:
        if (err < 0)
                rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
}

static void vxlan_fdb_switchdev_notifier_info(const struct vxlan_dev *vxlan,
                            const struct vxlan_fdb *fdb,
                            const struct vxlan_rdst *rd,
                            struct netlink_ext_ack *extack,
                            struct switchdev_notifier_vxlan_fdb_info *fdb_info)
{
        fdb_info->info.dev = vxlan->dev;
        fdb_info->info.extack = extack;
        fdb_info->remote_ip = rd->remote_ip;
        fdb_info->remote_port = rd->remote_port;
        fdb_info->remote_vni = rd->remote_vni;
        fdb_info->remote_ifindex = rd->remote_ifindex;
        memcpy(fdb_info->eth_addr, fdb->eth_addr, ETH_ALEN);
        fdb_info->vni = fdb->vni;
        fdb_info->offloaded = rd->offloaded;
        fdb_info->added_by_user = fdb->flags & NTF_VXLAN_ADDED_BY_USER;
}

static int vxlan_fdb_switchdev_call_notifiers(struct vxlan_dev *vxlan,
                                              struct vxlan_fdb *fdb,
                                              struct vxlan_rdst *rd,
                                              bool adding,
                                              struct netlink_ext_ack *extack)
{
        struct switchdev_notifier_vxlan_fdb_info info;
        enum switchdev_notifier_type notifier_type;
        int ret;

        if (WARN_ON(!rd))
                return 0;

        notifier_type = adding ? SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE
                               : SWITCHDEV_VXLAN_FDB_DEL_TO_DEVICE;
        vxlan_fdb_switchdev_notifier_info(vxlan, fdb, rd, NULL, &info);
        ret = call_switchdev_notifiers(notifier_type, vxlan->dev,
                                       &info.info, extack);
        return notifier_to_errno(ret);
}

static int vxlan_fdb_notify(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
                            struct vxlan_rdst *rd, int type, bool swdev_notify,
                            struct netlink_ext_ack *extack)
{
        int err;

        if (swdev_notify && rd) {
                switch (type) {
                case RTM_NEWNEIGH:
                        err = vxlan_fdb_switchdev_call_notifiers(vxlan, fdb, rd,
                                                                 true, extack);
                        if (err)
                                return err;
                        break;
                case RTM_DELNEIGH:
                        vxlan_fdb_switchdev_call_notifiers(vxlan, fdb, rd,
                                                           false, extack);
                        break;
                }
        }

        __vxlan_fdb_notify(vxlan, fdb, rd, type);
        return 0;
}

static void vxlan_ip_miss(struct net_device *dev, union vxlan_addr *ipa)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_fdb f = {
                .state = NUD_STALE,
        };
        struct vxlan_rdst remote = {
                .remote_ip = *ipa, /* goes to NDA_DST */
                .remote_vni = cpu_to_be32(VXLAN_N_VID),
        };

        vxlan_fdb_notify(vxlan, &f, &remote, RTM_GETNEIGH, true, NULL);
}

static void vxlan_fdb_miss(struct vxlan_dev *vxlan, const u8 eth_addr[ETH_ALEN])
{
        struct vxlan_fdb f = {
                .state = NUD_STALE,
        };
        struct vxlan_rdst remote = { };

        memcpy(f.eth_addr, eth_addr, ETH_ALEN);

        vxlan_fdb_notify(vxlan, &f, &remote, RTM_GETNEIGH, true, NULL);
}

/* Hash Ethernet address */
static u32 eth_hash(const unsigned char *addr)
{
        u64 value = get_unaligned((u64 *)addr);

        /* only want 6 bytes */
#ifdef __BIG_ENDIAN
        value >>= 16;
#else
        value <<= 16;
#endif
        return hash_64(value, FDB_HASH_BITS);
}

static u32 eth_vni_hash(const unsigned char *addr, __be32 vni)
{
        /* use 1 byte of OUI and 3 bytes of NIC */
        u32 key = get_unaligned((u32 *)(addr + 2));

        return jhash_2words(key, vni, vxlan_salt) & (FDB_HASH_SIZE - 1);
}

static u32 fdb_head_index(struct vxlan_dev *vxlan, const u8 *mac, __be32 vni)
{
        if (vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA)
                return eth_vni_hash(mac, vni);
        else
                return eth_hash(mac);
}

/* Hash chain to use given mac address */
static inline struct hlist_head *vxlan_fdb_head(struct vxlan_dev *vxlan,
                                                const u8 *mac, __be32 vni)
{
        return &vxlan->fdb_head[fdb_head_index(vxlan, mac, vni)];
}

/* Look up Ethernet address in forwarding table */
static struct vxlan_fdb *__vxlan_find_mac(struct vxlan_dev *vxlan,
                                          const u8 *mac, __be32 vni)
{
        struct hlist_head *head = vxlan_fdb_head(vxlan, mac, vni);
        struct vxlan_fdb *f;

        hlist_for_each_entry_rcu(f, head, hlist) {
                if (ether_addr_equal(mac, f->eth_addr)) {
                        if (vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA) {
                                if (vni == f->vni)
                                        return f;
                        } else {
                                return f;
                        }
                }
        }

        return NULL;
}

static struct vxlan_fdb *vxlan_find_mac(struct vxlan_dev *vxlan,
                                        const u8 *mac, __be32 vni)
{
        struct vxlan_fdb *f;

        f = __vxlan_find_mac(vxlan, mac, vni);
        if (f && f->used != jiffies)
                f->used = jiffies;

        return f;
}

/* caller should hold vxlan->hash_lock */
static struct vxlan_rdst *vxlan_fdb_find_rdst(struct vxlan_fdb *f,
                                              union vxlan_addr *ip, __be16 port,
                                              __be32 vni, __u32 ifindex)
{
        struct vxlan_rdst *rd;

        list_for_each_entry(rd, &f->remotes, list) {
                if (vxlan_addr_equal(&rd->remote_ip, ip) &&
                    rd->remote_port == port &&
                    rd->remote_vni == vni &&
                    rd->remote_ifindex == ifindex)
                        return rd;
        }

        return NULL;
}

int vxlan_fdb_find_uc(struct net_device *dev, const u8 *mac, __be32 vni,
                      struct switchdev_notifier_vxlan_fdb_info *fdb_info)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        u8 eth_addr[ETH_ALEN + 2] = { 0 };
        struct vxlan_rdst *rdst;
        struct vxlan_fdb *f;
        int rc = 0;

        if (is_multicast_ether_addr(mac) ||
            is_zero_ether_addr(mac))
                return -EINVAL;

        ether_addr_copy(eth_addr, mac);

        rcu_read_lock();

        f = __vxlan_find_mac(vxlan, eth_addr, vni);
        if (!f) {
                rc = -ENOENT;
                goto out;
        }

        rdst = first_remote_rcu(f);
        vxlan_fdb_switchdev_notifier_info(vxlan, f, rdst, NULL, fdb_info);

out:
        rcu_read_unlock();
        return rc;
}
EXPORT_SYMBOL_GPL(vxlan_fdb_find_uc);

static int vxlan_fdb_notify_one(struct notifier_block *nb,
                                const struct vxlan_dev *vxlan,
                                const struct vxlan_fdb *f,
                                const struct vxlan_rdst *rdst,
                                struct netlink_ext_ack *extack)
{
        struct switchdev_notifier_vxlan_fdb_info fdb_info;
        int rc;

        vxlan_fdb_switchdev_notifier_info(vxlan, f, rdst, extack, &fdb_info);
        rc = nb->notifier_call(nb, SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE,
                               &fdb_info);
        return notifier_to_errno(rc);
}

int vxlan_fdb_replay(const struct net_device *dev, __be32 vni,
                     struct notifier_block *nb,
                     struct netlink_ext_ack *extack)
{
        struct vxlan_dev *vxlan;
        struct vxlan_rdst *rdst;
        struct vxlan_fdb *f;
        unsigned int h;
        int rc = 0;

        if (!netif_is_vxlan(dev))
                return -EINVAL;
        vxlan = netdev_priv(dev);

        for (h = 0; h < FDB_HASH_SIZE; ++h) {
                spin_lock_bh(&vxlan->hash_lock[h]);
                hlist_for_each_entry(f, &vxlan->fdb_head[h], hlist) {
                        if (f->vni == vni) {
                                list_for_each_entry(rdst, &f->remotes, list) {
                                        rc = vxlan_fdb_notify_one(nb, vxlan,
                                                                  f, rdst,
                                                                  extack);
                                        if (rc)
                                                goto unlock;
                                }
                        }
                }
                spin_unlock_bh(&vxlan->hash_lock[h]);
        }
        return 0;

unlock:
        spin_unlock_bh(&vxlan->hash_lock[h]);
        return rc;
}
EXPORT_SYMBOL_GPL(vxlan_fdb_replay);

void vxlan_fdb_clear_offload(const struct net_device *dev, __be32 vni)
{
        struct vxlan_dev *vxlan;
        struct vxlan_rdst *rdst;
        struct vxlan_fdb *f;
        unsigned int h;

        if (!netif_is_vxlan(dev))
                return;
        vxlan = netdev_priv(dev);

        for (h = 0; h < FDB_HASH_SIZE; ++h) {
                spin_lock_bh(&vxlan->hash_lock[h]);
                hlist_for_each_entry(f, &vxlan->fdb_head[h], hlist)
                        if (f->vni == vni)
                                list_for_each_entry(rdst, &f->remotes, list)
                                        rdst->offloaded = false;
                spin_unlock_bh(&vxlan->hash_lock[h]);
        }

}
EXPORT_SYMBOL_GPL(vxlan_fdb_clear_offload);

/* Replace destination of unicast mac */
static int vxlan_fdb_replace(struct vxlan_fdb *f,
                             union vxlan_addr *ip, __be16 port, __be32 vni,
                             __u32 ifindex, struct vxlan_rdst *oldrd)
{
        struct vxlan_rdst *rd;

        rd = vxlan_fdb_find_rdst(f, ip, port, vni, ifindex);
        if (rd)
                return 0;

        rd = list_first_entry_or_null(&f->remotes, struct vxlan_rdst, list);
        if (!rd)
                return 0;

        *oldrd = *rd;
        dst_cache_reset(&rd->dst_cache);
        rd->remote_ip = *ip;
        rd->remote_port = port;
        rd->remote_vni = vni;
        rd->remote_ifindex = ifindex;
        rd->offloaded = false;
        return 1;
}

/* Add/update destinations for multicast */
static int vxlan_fdb_append(struct vxlan_fdb *f,
                            union vxlan_addr *ip, __be16 port, __be32 vni,
                            __u32 ifindex, struct vxlan_rdst **rdp)
{
        struct vxlan_rdst *rd;

        rd = vxlan_fdb_find_rdst(f, ip, port, vni, ifindex);
        if (rd)
                return 0;

        rd = kmalloc(sizeof(*rd), GFP_ATOMIC);
        if (rd == NULL)
                return -ENOBUFS;

        if (dst_cache_init(&rd->dst_cache, GFP_ATOMIC)) {
                kfree(rd);
                return -ENOBUFS;
        }

        rd->remote_ip = *ip;
        rd->remote_port = port;
        rd->offloaded = false;
        rd->remote_vni = vni;
        rd->remote_ifindex = ifindex;

        list_add_tail_rcu(&rd->list, &f->remotes);

        *rdp = rd;
        return 1;
}

static struct vxlanhdr *vxlan_gro_remcsum(struct sk_buff *skb,
                                          unsigned int off,
                                          struct vxlanhdr *vh, size_t hdrlen,
                                          __be32 vni_field,
                                          struct gro_remcsum *grc,
                                          bool nopartial)
{
        size_t start, offset;

        if (skb->remcsum_offload)
                return vh;

        if (!NAPI_GRO_CB(skb)->csum_valid)
                return NULL;

        start = vxlan_rco_start(vni_field);
        offset = start + vxlan_rco_offset(vni_field);

        vh = skb_gro_remcsum_process(skb, (void *)vh, off, hdrlen,
                                     start, offset, grc, nopartial);

        skb->remcsum_offload = 1;

        return vh;
}

static struct sk_buff *vxlan_gro_receive(struct sock *sk,
                                         struct list_head *head,
                                         struct sk_buff *skb)
{
        struct sk_buff *pp = NULL;
        struct sk_buff *p;
        struct vxlanhdr *vh, *vh2;
        unsigned int hlen, off_vx;
        int flush = 1;
        struct vxlan_sock *vs = rcu_dereference_sk_user_data(sk);
        __be32 flags;
        struct gro_remcsum grc;

        skb_gro_remcsum_init(&grc);

        off_vx = skb_gro_offset(skb);
        hlen = off_vx + sizeof(*vh);
        vh   = skb_gro_header_fast(skb, off_vx);
        if (skb_gro_header_hard(skb, hlen)) {
                vh = skb_gro_header_slow(skb, hlen, off_vx);
                if (unlikely(!vh))
                        goto out;
        }

        skb_gro_postpull_rcsum(skb, vh, sizeof(struct vxlanhdr));

        flags = vh->vx_flags;

        if ((flags & VXLAN_HF_RCO) && (vs->flags & VXLAN_F_REMCSUM_RX)) {
                vh = vxlan_gro_remcsum(skb, off_vx, vh, sizeof(struct vxlanhdr),
                                       vh->vx_vni, &grc,
                                       !!(vs->flags &
                                          VXLAN_F_REMCSUM_NOPARTIAL));

                if (!vh)
                        goto out;
        }

        skb_gro_pull(skb, sizeof(struct vxlanhdr)); /* pull vxlan header */

        list_for_each_entry(p, head, list) {
                if (!NAPI_GRO_CB(p)->same_flow)
                        continue;

                vh2 = (struct vxlanhdr *)(p->data + off_vx);
                if (vh->vx_flags != vh2->vx_flags ||
                    vh->vx_vni != vh2->vx_vni) {
                        NAPI_GRO_CB(p)->same_flow = 0;
                        continue;
                }
        }

        pp = call_gro_receive(eth_gro_receive, head, skb);
        flush = 0;

out:
        skb_gro_flush_final_remcsum(skb, pp, flush, &grc);

        return pp;
}

static int vxlan_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
{
        /* Sets 'skb->inner_mac_header' since we are always called with
         * 'skb->encapsulation' set.
         */
        return eth_gro_complete(skb, nhoff + sizeof(struct vxlanhdr));
}

static struct vxlan_fdb *vxlan_fdb_alloc(struct vxlan_dev *vxlan, const u8 *mac,
                                         __u16 state, __be32 src_vni,
                                         __u16 ndm_flags)
{
        struct vxlan_fdb *f;

        f = kmalloc(sizeof(*f), GFP_ATOMIC);
        if (!f)
                return NULL;
        f->state = state;
        f->flags = ndm_flags;
        f->updated = f->used = jiffies;
        f->vni = src_vni;
        f->nh = NULL;
        RCU_INIT_POINTER(f->vdev, vxlan);
        INIT_LIST_HEAD(&f->nh_list);
        INIT_LIST_HEAD(&f->remotes);
        memcpy(f->eth_addr, mac, ETH_ALEN);

        return f;
}

static void vxlan_fdb_insert(struct vxlan_dev *vxlan, const u8 *mac,
                             __be32 src_vni, struct vxlan_fdb *f)
{
        ++vxlan->addrcnt;
        hlist_add_head_rcu(&f->hlist,
                           vxlan_fdb_head(vxlan, mac, src_vni));
}

static int vxlan_fdb_nh_update(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
                               u32 nhid, struct netlink_ext_ack *extack)
{
        struct nexthop *old_nh = rtnl_dereference(fdb->nh);
        struct nexthop *nh;
        int err = -EINVAL;

        if (old_nh && old_nh->id == nhid)
                return 0;

        nh = nexthop_find_by_id(vxlan->net, nhid);
        if (!nh) {
                NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
                goto err_inval;
        }

        if (nh) {
                if (!nexthop_get(nh)) {
                        NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
                        nh = NULL;
                        goto err_inval;
                }
                if (!nexthop_is_fdb(nh)) {
                        NL_SET_ERR_MSG(extack, "Nexthop is not a fdb nexthop");
                        goto err_inval;
                }

                if (!nexthop_is_multipath(nh)) {
                        NL_SET_ERR_MSG(extack, "Nexthop is not a multipath group");
                        goto err_inval;
                }

                /* check nexthop group family */
                switch (vxlan->default_dst.remote_ip.sa.sa_family) {
                case AF_INET:
                        if (!nexthop_has_v4(nh)) {
                                err = -EAFNOSUPPORT;
                                NL_SET_ERR_MSG(extack, "Nexthop group family not supported");
                                goto err_inval;
                        }
                        break;
                case AF_INET6:
                        if (nexthop_has_v4(nh)) {
                                err = -EAFNOSUPPORT;
                                NL_SET_ERR_MSG(extack, "Nexthop group family not supported");
                                goto err_inval;
                        }
                }
        }

        if (old_nh) {
                list_del_rcu(&fdb->nh_list);
                nexthop_put(old_nh);
        }
        rcu_assign_pointer(fdb->nh, nh);
        list_add_tail_rcu(&fdb->nh_list, &nh->fdb_list);
        return 1;

err_inval:
        if (nh)
                nexthop_put(nh);
        return err;
}

static int vxlan_fdb_create(struct vxlan_dev *vxlan,
                            const u8 *mac, union vxlan_addr *ip,
                            __u16 state, __be16 port, __be32 src_vni,
                            __be32 vni, __u32 ifindex, __u16 ndm_flags,
                            u32 nhid, struct vxlan_fdb **fdb,
                            struct netlink_ext_ack *extack)
{
        struct vxlan_rdst *rd = NULL;
        struct vxlan_fdb *f;
        int rc;

        if (vxlan->cfg.addrmax &&
            vxlan->addrcnt >= vxlan->cfg.addrmax)
                return -ENOSPC;

        netdev_dbg(vxlan->dev, "add %pM -> %pIS\n", mac, ip);
        f = vxlan_fdb_alloc(vxlan, mac, state, src_vni, ndm_flags);
        if (!f)
                return -ENOMEM;

        if (nhid)
                rc = vxlan_fdb_nh_update(vxlan, f, nhid, extack);
        else
                rc = vxlan_fdb_append(f, ip, port, vni, ifindex, &rd);
        if (rc < 0)
                goto errout;

        *fdb = f;

        return 0;

errout:
        kfree(f);
        return rc;
}

static void __vxlan_fdb_free(struct vxlan_fdb *f)
{
        struct vxlan_rdst *rd, *nd;
        struct nexthop *nh;

        nh = rcu_dereference_raw(f->nh);
        if (nh) {
                rcu_assign_pointer(f->nh, NULL);
                rcu_assign_pointer(f->vdev, NULL);
                nexthop_put(nh);
        }

        list_for_each_entry_safe(rd, nd, &f->remotes, list) {
                dst_cache_destroy(&rd->dst_cache);
                kfree(rd);
        }
        kfree(f);
}

static void vxlan_fdb_free(struct rcu_head *head)
{
        struct vxlan_fdb *f = container_of(head, struct vxlan_fdb, rcu);

        __vxlan_fdb_free(f);
}

static void vxlan_fdb_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f,
                              bool do_notify, bool swdev_notify)
{
        struct vxlan_rdst *rd;

        netdev_dbg(vxlan->dev, "delete %pM\n", f->eth_addr);

        --vxlan->addrcnt;
        if (do_notify) {
                if (rcu_access_pointer(f->nh))
                        vxlan_fdb_notify(vxlan, f, NULL, RTM_DELNEIGH,
                                         swdev_notify, NULL);
                else
                        list_for_each_entry(rd, &f->remotes, list)
                                vxlan_fdb_notify(vxlan, f, rd, RTM_DELNEIGH,
                                                 swdev_notify, NULL);
        }

        hlist_del_rcu(&f->hlist);
        list_del_rcu(&f->nh_list);
        call_rcu(&f->rcu, vxlan_fdb_free);
}

static void vxlan_dst_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_fdb_update_existing(struct vxlan_dev *vxlan,
                                     union vxlan_addr *ip,
                                     __u16 state, __u16 flags,
                                     __be16 port, __be32 vni,
                                     __u32 ifindex, __u16 ndm_flags,
                                     struct vxlan_fdb *f, u32 nhid,
                                     bool swdev_notify,
                                     struct netlink_ext_ack *extack)
{
        __u16 fdb_flags = (ndm_flags & ~NTF_USE);
        struct vxlan_rdst *rd = NULL;
        struct vxlan_rdst oldrd;
        int notify = 0;
        int rc = 0;
        int err;

        if (nhid && !rcu_access_pointer(f->nh)) {
                NL_SET_ERR_MSG(extack,
                               "Cannot replace an existing non nexthop fdb with a nexthop");
                return -EOPNOTSUPP;
        }

        if (nhid && (flags & NLM_F_APPEND)) {
                NL_SET_ERR_MSG(extack,
                               "Cannot append to a nexthop fdb");
                return -EOPNOTSUPP;
        }

        /* Do not allow an externally learned entry to take over an entry added
         * by the user.
         */
        if (!(fdb_flags & NTF_EXT_LEARNED) ||
            !(f->flags & NTF_VXLAN_ADDED_BY_USER)) {
                if (f->state != state) {
                        f->state = state;
                        f->updated = jiffies;
                        notify = 1;
                }
                if (f->flags != fdb_flags) {
                        f->flags = fdb_flags;
                        f->updated = jiffies;
                        notify = 1;
                }
        }

        if ((flags & NLM_F_REPLACE)) {
                /* Only change unicasts */
                if (!(is_multicast_ether_addr(f->eth_addr) ||
                      is_zero_ether_addr(f->eth_addr))) {
                        if (nhid) {
                                rc = vxlan_fdb_nh_update(vxlan, f, nhid, extack);
                                if (rc < 0)
                                        return rc;
                        } else {
                                rc = vxlan_fdb_replace(f, ip, port, vni,
                                                       ifindex, &oldrd);
                        }
                        notify |= rc;
                } else {
                        NL_SET_ERR_MSG(extack, "Cannot replace non-unicast fdb entries");
                        return -EOPNOTSUPP;
                }
        }
        if ((flags & NLM_F_APPEND) &&
            (is_multicast_ether_addr(f->eth_addr) ||
             is_zero_ether_addr(f->eth_addr))) {
                rc = vxlan_fdb_append(f, ip, port, vni, ifindex, &rd);

                if (rc < 0)
                        return rc;
                notify |= rc;
        }

        if (ndm_flags & NTF_USE)
                f->used = jiffies;

        if (notify) {
                if (rd == NULL)
                        rd = first_remote_rtnl(f);

                err = vxlan_fdb_notify(vxlan, f, rd, RTM_NEWNEIGH,
                                       swdev_notify, extack);
                if (err)
                        goto err_notify;
        }

        return 0;

err_notify:
        if (nhid)
                return err;
        if ((flags & NLM_F_REPLACE) && rc)
                *rd = oldrd;
        else if ((flags & NLM_F_APPEND) && rc) {
                list_del_rcu(&rd->list);
                call_rcu(&rd->rcu, vxlan_dst_free);
        }
        return err;
}

static int vxlan_fdb_update_create(struct vxlan_dev *vxlan,
                                   const u8 *mac, union vxlan_addr *ip,
                                   __u16 state, __u16 flags,
                                   __be16 port, __be32 src_vni, __be32 vni,
                                   __u32 ifindex, __u16 ndm_flags, u32 nhid,
                                   bool swdev_notify,
                                   struct netlink_ext_ack *extack)
{
        __u16 fdb_flags = (ndm_flags & ~NTF_USE);
        struct vxlan_fdb *f;
        int rc;

        /* Disallow replace to add a multicast entry */
        if ((flags & NLM_F_REPLACE) &&
            (is_multicast_ether_addr(mac) || is_zero_ether_addr(mac)))
                return -EOPNOTSUPP;

        netdev_dbg(vxlan->dev, "add %pM -> %pIS\n", mac, ip);
        rc = vxlan_fdb_create(vxlan, mac, ip, state, port, src_vni,
                              vni, ifindex, fdb_flags, nhid, &f, extack);
        if (rc < 0)
                return rc;

        vxlan_fdb_insert(vxlan, mac, src_vni, f);
        rc = vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f), RTM_NEWNEIGH,
                              swdev_notify, extack);
        if (rc)
                goto err_notify;

        return 0;

err_notify:
        vxlan_fdb_destroy(vxlan, f, false, false);
        return rc;
}

/* Add new entry to forwarding table -- assumes lock held */
static int vxlan_fdb_update(struct vxlan_dev *vxlan,
                            const u8 *mac, union vxlan_addr *ip,
                            __u16 state, __u16 flags,
                            __be16 port, __be32 src_vni, __be32 vni,
                            __u32 ifindex, __u16 ndm_flags, u32 nhid,
                            bool swdev_notify,
                            struct netlink_ext_ack *extack)
{
        struct vxlan_fdb *f;

        f = __vxlan_find_mac(vxlan, mac, src_vni);
        if (f) {
                if (flags & NLM_F_EXCL) {
                        netdev_dbg(vxlan->dev,
                                   "lost race to create %pM\n", mac);
                        return -EEXIST;
                }

                return vxlan_fdb_update_existing(vxlan, ip, state, flags, port,
                                                 vni, ifindex, ndm_flags, f,
                                                 nhid, swdev_notify, extack);
        } else {
                if (!(flags & NLM_F_CREATE))
                        return -ENOENT;

                return vxlan_fdb_update_create(vxlan, mac, ip, state, flags,
                                               port, src_vni, vni, ifindex,
                                               ndm_flags, nhid, swdev_notify,
                                               extack);
        }
}

static void vxlan_fdb_dst_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f,
                                  struct vxlan_rdst *rd, bool swdev_notify)
{
        list_del_rcu(&rd->list);
        vxlan_fdb_notify(vxlan, f, rd, RTM_DELNEIGH, swdev_notify, NULL);
        call_rcu(&rd->rcu, vxlan_dst_free);
}

static int vxlan_fdb_parse(struct nlattr *tb[], struct vxlan_dev *vxlan,
                           union vxlan_addr *ip, __be16 *port, __be32 *src_vni,
                           __be32 *vni, u32 *ifindex, u32 *nhid)
{
        struct net *net = dev_net(vxlan->dev);
        int err;

        if (tb[NDA_NH_ID] && (tb[NDA_DST] || tb[NDA_VNI] || tb[NDA_IFINDEX] ||
            tb[NDA_PORT]))
                return -EINVAL;

        if (tb[NDA_DST]) {
                err = vxlan_nla_get_addr(ip, tb[NDA_DST]);
                if (err)
                        return err;
        } else {
                union vxlan_addr *remote = &vxlan->default_dst.remote_ip;

                if (remote->sa.sa_family == AF_INET) {
                        ip->sin.sin_addr.s_addr = htonl(INADDR_ANY);
                        ip->sa.sa_family = AF_INET;
#if IS_ENABLED(CONFIG_IPV6)
                } else {
                        ip->sin6.sin6_addr = in6addr_any;
                        ip->sa.sa_family = AF_INET6;
#endif
                }
        }

        if (tb[NDA_PORT]) {
                if (nla_len(tb[NDA_PORT]) != sizeof(__be16))
                        return -EINVAL;
                *port = nla_get_be16(tb[NDA_PORT]);
        } else {
                *port = vxlan->cfg.dst_port;
        }

        if (tb[NDA_VNI]) {
                if (nla_len(tb[NDA_VNI]) != sizeof(u32))
                        return -EINVAL;
                *vni = cpu_to_be32(nla_get_u32(tb[NDA_VNI]));
        } else {
                *vni = vxlan->default_dst.remote_vni;
        }

        if (tb[NDA_SRC_VNI]) {
                if (nla_len(tb[NDA_SRC_VNI]) != sizeof(u32))
                        return -EINVAL;
                *src_vni = cpu_to_be32(nla_get_u32(tb[NDA_SRC_VNI]));
        } else {
                *src_vni = vxlan->default_dst.remote_vni;
        }

        if (tb[NDA_IFINDEX]) {
                struct net_device *tdev;

                if (nla_len(tb[NDA_IFINDEX]) != sizeof(u32))
                        return -EINVAL;
                *ifindex = nla_get_u32(tb[NDA_IFINDEX]);
                tdev = __dev_get_by_index(net, *ifindex);
                if (!tdev)
                        return -EADDRNOTAVAIL;
        } else {
                *ifindex = 0;
        }

        if (tb[NDA_NH_ID])
                *nhid = nla_get_u32(tb[NDA_NH_ID]);
        else
                *nhid = 0;

        return 0;
}

/* Add static entry (via netlink) */
static int vxlan_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
                         struct net_device *dev,
                         const unsigned char *addr, u16 vid, u16 flags,
                         struct netlink_ext_ack *extack)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        /* struct net *net = dev_net(vxlan->dev); */
        union vxlan_addr ip;
        __be16 port;
        __be32 src_vni, vni;
        u32 ifindex, nhid;
        u32 hash_index;
        int err;

        if (!(ndm->ndm_state & (NUD_PERMANENT|NUD_REACHABLE))) {
                pr_info("RTM_NEWNEIGH with invalid state %#x\n",
                        ndm->ndm_state);
                return -EINVAL;
        }

        if (!tb || (!tb[NDA_DST] && !tb[NDA_NH_ID]))
                return -EINVAL;

        err = vxlan_fdb_parse(tb, vxlan, &ip, &port, &src_vni, &vni, &ifindex,
                              &nhid);
        if (err)
                return err;

        if (vxlan->default_dst.remote_ip.sa.sa_family != ip.sa.sa_family)
                return -EAFNOSUPPORT;

        hash_index = fdb_head_index(vxlan, addr, src_vni);
        spin_lock_bh(&vxlan->hash_lock[hash_index]);
        err = vxlan_fdb_update(vxlan, addr, &ip, ndm->ndm_state, flags,
                               port, src_vni, vni, ifindex,
                               ndm->ndm_flags | NTF_VXLAN_ADDED_BY_USER,
                               nhid, true, extack);
        spin_unlock_bh(&vxlan->hash_lock[hash_index]);

        return err;
}

static int __vxlan_fdb_delete(struct vxlan_dev *vxlan,
                              const unsigned char *addr, union vxlan_addr ip,
                              __be16 port, __be32 src_vni, __be32 vni,
                              u32 ifindex, bool swdev_notify)
{
        struct vxlan_rdst *rd = NULL;
        struct vxlan_fdb *f;
        int err = -ENOENT;

        f = vxlan_find_mac(vxlan, addr, src_vni);
        if (!f)
                return err;

        if (!vxlan_addr_any(&ip)) {
                rd = vxlan_fdb_find_rdst(f, &ip, port, vni, ifindex);
                if (!rd)
                        goto out;
        }

        /* remove a destination if it's not the only one on the list,
         * otherwise destroy the fdb entry
         */
        if (rd && !list_is_singular(&f->remotes)) {
                vxlan_fdb_dst_destroy(vxlan, f, rd, swdev_notify);
                goto out;
        }

        vxlan_fdb_destroy(vxlan, f, true, swdev_notify);

out:
        return 0;
}

/* Delete entry (via netlink) */
static int vxlan_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
                            struct net_device *dev,
                            const unsigned char *addr, u16 vid)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        union vxlan_addr ip;
        __be32 src_vni, vni;
        u32 ifindex, nhid;
        u32 hash_index;
        __be16 port;
        int err;

        err = vxlan_fdb_parse(tb, vxlan, &ip, &port, &src_vni, &vni, &ifindex,
                              &nhid);
        if (err)
                return err;

        hash_index = fdb_head_index(vxlan, addr, src_vni);
        spin_lock_bh(&vxlan->hash_lock[hash_index]);
        err = __vxlan_fdb_delete(vxlan, addr, ip, port, src_vni, vni, ifindex,
                                 true);
        spin_unlock_bh(&vxlan->hash_lock[hash_index]);

        return err;
}

/* Dump forwarding table */
static int vxlan_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb,
                          struct net_device *dev,
                          struct net_device *filter_dev, int *idx)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        unsigned int h;
        int err = 0;

        for (h = 0; h < FDB_HASH_SIZE; ++h) {
                struct vxlan_fdb *f;

                rcu_read_lock();
                hlist_for_each_entry_rcu(f, &vxlan->fdb_head[h], hlist) {
                        struct vxlan_rdst *rd;

                        if (rcu_access_pointer(f->nh)) {
                                if (*idx < cb->args[2])
                                        goto skip_nh;
                                err = vxlan_fdb_info(skb, vxlan, f,
                                                     NETLINK_CB(cb->skb).portid,
                                                     cb->nlh->nlmsg_seq,
                                                     RTM_NEWNEIGH,
                                                     NLM_F_MULTI, NULL);
                                if (err < 0) {
                                        rcu_read_unlock();
                                        goto out;
                                }
skip_nh:
                                *idx += 1;
                                continue;
                        }

                        list_for_each_entry_rcu(rd, &f->remotes, list) {
                                if (*idx < cb->args[2])
                                        goto skip;

                                err = vxlan_fdb_info(skb, vxlan, f,
                                                     NETLINK_CB(cb->skb).portid,
                                                     cb->nlh->nlmsg_seq,
                                                     RTM_NEWNEIGH,
                                                     NLM_F_MULTI, rd);
                                if (err < 0) {
                                        rcu_read_unlock();
                                        goto out;
                                }
skip:
                                *idx += 1;
                        }
                }
                rcu_read_unlock();
        }
out:
        return err;
}

static int vxlan_fdb_get(struct sk_buff *skb,
                         struct nlattr *tb[],
                         struct net_device *dev,
                         const unsigned char *addr,
                         u16 vid, u32 portid, u32 seq,
                         struct netlink_ext_ack *extack)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_fdb *f;
        __be32 vni;
        int err;

        if (tb[NDA_VNI])
                vni = cpu_to_be32(nla_get_u32(tb[NDA_VNI]));
        else
                vni = vxlan->default_dst.remote_vni;

        rcu_read_lock();

        f = __vxlan_find_mac(vxlan, addr, vni);
        if (!f) {
                NL_SET_ERR_MSG(extack, "Fdb entry not found");
                err = -ENOENT;
                goto errout;
        }

        err = vxlan_fdb_info(skb, vxlan, f, portid, seq,
                             RTM_NEWNEIGH, 0, first_remote_rcu(f));
errout:
        rcu_read_unlock();
        return err;
}

/* Watch incoming packets to learn mapping between Ethernet address
 * and Tunnel endpoint.
 * Return true if packet is bogus and should be dropped.
 */
static bool vxlan_snoop(struct net_device *dev,
                        union vxlan_addr *src_ip, const u8 *src_mac,
                        u32 src_ifindex, __be32 vni)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_fdb *f;
        u32 ifindex = 0;

#if IS_ENABLED(CONFIG_IPV6)
        if (src_ip->sa.sa_family == AF_INET6 &&
            (ipv6_addr_type(&src_ip->sin6.sin6_addr) & IPV6_ADDR_LINKLOCAL))
                ifindex = src_ifindex;
#endif

        f = vxlan_find_mac(vxlan, src_mac, vni);
        if (likely(f)) {
                struct vxlan_rdst *rdst = first_remote_rcu(f);

                if (likely(vxlan_addr_equal(&rdst->remote_ip, src_ip) &&
                           rdst->remote_ifindex == ifindex))
                        return false;

                /* Don't migrate static entries, drop packets */
                if (f->state & (NUD_PERMANENT | NUD_NOARP))
                        return true;

                /* Don't override an fdb with nexthop with a learnt entry */
                if (rcu_access_pointer(f->nh))
                        return true;

                if (net_ratelimit())
                        netdev_info(dev,
                                    "%pM migrated from %pIS to %pIS\n",
                                    src_mac, &rdst->remote_ip.sa, &src_ip->sa);

                rdst->remote_ip = *src_ip;
                f->updated = jiffies;
                vxlan_fdb_notify(vxlan, f, rdst, RTM_NEWNEIGH, true, NULL);
        } else {
                u32 hash_index = fdb_head_index(vxlan, src_mac, vni);

                /* learned new entry */
                spin_lock(&vxlan->hash_lock[hash_index]);

                /* close off race between vxlan_flush and incoming packets */
                if (netif_running(dev))
                        vxlan_fdb_update(vxlan, src_mac, src_ip,
                                         NUD_REACHABLE,
                                         NLM_F_EXCL|NLM_F_CREATE,
                                         vxlan->cfg.dst_port,
                                         vni,
                                         vxlan->default_dst.remote_vni,
                                         ifindex, NTF_SELF, 0, true, NULL);
                spin_unlock(&vxlan->hash_lock[hash_index]);
        }

        return false;
}

/* See if multicast group is already in use by other ID */
static bool vxlan_group_used(struct vxlan_net *vn, struct vxlan_dev *dev)
{
        struct vxlan_dev *vxlan;
        struct vxlan_sock *sock4;
#if IS_ENABLED(CONFIG_IPV6)
        struct vxlan_sock *sock6;
#endif
        unsigned short family = dev->default_dst.remote_ip.sa.sa_family;

        sock4 = rtnl_dereference(dev->vn4_sock);

        /* The vxlan_sock is only used by dev, leaving group has
         * no effect on other vxlan devices.
         */
        if (family == AF_INET && sock4 && refcount_read(&sock4->refcnt) == 1)
                return false;
#if IS_ENABLED(CONFIG_IPV6)
        sock6 = rtnl_dereference(dev->vn6_sock);
        if (family == AF_INET6 && sock6 && refcount_read(&sock6->refcnt) == 1)
                return false;
#endif

        list_for_each_entry(vxlan, &vn->vxlan_list, next) {
                if (!netif_running(vxlan->dev) || vxlan == dev)
                        continue;

                if (family == AF_INET &&
                    rtnl_dereference(vxlan->vn4_sock) != sock4)
                        continue;
#if IS_ENABLED(CONFIG_IPV6)
                if (family == AF_INET6 &&
                    rtnl_dereference(vxlan->vn6_sock) != sock6)
                        continue;
#endif

                if (!vxlan_addr_equal(&vxlan->default_dst.remote_ip,
                                      &dev->default_dst.remote_ip))
                        continue;

                if (vxlan->default_dst.remote_ifindex !=
                    dev->default_dst.remote_ifindex)
                        continue;

                return true;
        }

        return false;
}

static bool __vxlan_sock_release_prep(struct vxlan_sock *vs)
{
        struct vxlan_net *vn;

        if (!vs)
                return false;
        if (!refcount_dec_and_test(&vs->refcnt))
                return false;

        vn = net_generic(sock_net(vs->sock->sk), vxlan_net_id);
        spin_lock(&vn->sock_lock);
        hlist_del_rcu(&vs->hlist);
        udp_tunnel_notify_del_rx_port(vs->sock,
                                      (vs->flags & VXLAN_F_GPE) ?
                                      UDP_TUNNEL_TYPE_VXLAN_GPE :
                                      UDP_TUNNEL_TYPE_VXLAN);
        spin_unlock(&vn->sock_lock);

        return true;
}

static void vxlan_sock_release(struct vxlan_dev *vxlan)
{
        struct vxlan_sock *sock4 = rtnl_dereference(vxlan->vn4_sock);
#if IS_ENABLED(CONFIG_IPV6)
        struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);

        RCU_INIT_POINTER(vxlan->vn6_sock, NULL);
#endif

        RCU_INIT_POINTER(vxlan->vn4_sock, NULL);
        synchronize_net();

        vxlan_vs_del_dev(vxlan);

        if (__vxlan_sock_release_prep(sock4)) {
                udp_tunnel_sock_release(sock4->sock);
                kfree(sock4);
        }

#if IS_ENABLED(CONFIG_IPV6)
        if (__vxlan_sock_release_prep(sock6)) {
                udp_tunnel_sock_release(sock6->sock);
                kfree(sock6);
        }
#endif
}

/* Update multicast group membership when first VNI on
 * multicast address is brought up
 */
static int vxlan_igmp_join(struct vxlan_dev *vxlan)
{
        struct sock *sk;
        union vxlan_addr *ip = &vxlan->default_dst.remote_ip;
        int ifindex = vxlan->default_dst.remote_ifindex;
        int ret = -EINVAL;

        if (ip->sa.sa_family == AF_INET) {
                struct vxlan_sock *sock4 = rtnl_dereference(vxlan->vn4_sock);
                struct ip_mreqn mreq = {
                        .imr_multiaddr.s_addr   = ip->sin.sin_addr.s_addr,
                        .imr_ifindex            = ifindex,
                };

                sk = sock4->sock->sk;
                lock_sock(sk);
                ret = ip_mc_join_group(sk, &mreq);
                release_sock(sk);
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);

                sk = sock6->sock->sk;
                lock_sock(sk);
                ret = ipv6_stub->ipv6_sock_mc_join(sk, ifindex,
                                                   &ip->sin6.sin6_addr);
                release_sock(sk);
#endif
        }

        return ret;
}

/* Inverse of vxlan_igmp_join when last VNI is brought down */
static int vxlan_igmp_leave(struct vxlan_dev *vxlan)
{
        struct sock *sk;
        union vxlan_addr *ip = &vxlan->default_dst.remote_ip;
        int ifindex = vxlan->default_dst.remote_ifindex;
        int ret = -EINVAL;

        if (ip->sa.sa_family == AF_INET) {
                struct vxlan_sock *sock4 = rtnl_dereference(vxlan->vn4_sock);
                struct ip_mreqn mreq = {
                        .imr_multiaddr.s_addr   = ip->sin.sin_addr.s_addr,
                        .imr_ifindex            = ifindex,
                };

                sk = sock4->sock->sk;
                lock_sock(sk);
                ret = ip_mc_leave_group(sk, &mreq);
                release_sock(sk);
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);

                sk = sock6->sock->sk;
                lock_sock(sk);
                ret = ipv6_stub->ipv6_sock_mc_drop(sk, ifindex,
                                                   &ip->sin6.sin6_addr);
                release_sock(sk);
#endif
        }

        return ret;
}

static bool vxlan_remcsum(struct vxlanhdr *unparsed,
                          struct sk_buff *skb, u32 vxflags)
{
        size_t start, offset;

        if (!(unparsed->vx_flags & VXLAN_HF_RCO) || skb->remcsum_offload)
                goto out;

        start = vxlan_rco_start(unparsed->vx_vni);
        offset = start + vxlan_rco_offset(unparsed->vx_vni);

        if (!pskb_may_pull(skb, offset + sizeof(u16)))
                return false;

        skb_remcsum_process(skb, (void *)(vxlan_hdr(skb) + 1), start, offset,
                            !!(vxflags & VXLAN_F_REMCSUM_NOPARTIAL));
out:
        unparsed->vx_flags &= ~VXLAN_HF_RCO;
        unparsed->vx_vni &= VXLAN_VNI_MASK;
        return true;
}

static void vxlan_parse_gbp_hdr(struct vxlanhdr *unparsed,
                                struct sk_buff *skb, u32 vxflags,
                                struct vxlan_metadata *md)
{
        struct vxlanhdr_gbp *gbp = (struct vxlanhdr_gbp *)unparsed;
        struct metadata_dst *tun_dst;

        if (!(unparsed->vx_flags & VXLAN_HF_GBP))
                goto out;

        md->gbp = ntohs(gbp->policy_id);

        tun_dst = (struct metadata_dst *)skb_dst(skb);
        if (tun_dst) {
                tun_dst->u.tun_info.key.tun_flags |= TUNNEL_VXLAN_OPT;
                tun_dst->u.tun_info.options_len = sizeof(*md);
        }
        if (gbp->dont_learn)
                md->gbp |= VXLAN_GBP_DONT_LEARN;

        if (gbp->policy_applied)
                md->gbp |= VXLAN_GBP_POLICY_APPLIED;

        /* In flow-based mode, GBP is carried in dst_metadata */
        if (!(vxflags & VXLAN_F_COLLECT_METADATA))
                skb->mark = md->gbp;
out:
        unparsed->vx_flags &= ~VXLAN_GBP_USED_BITS;
}

static bool vxlan_parse_gpe_hdr(struct vxlanhdr *unparsed,
                                __be16 *protocol,
                                struct sk_buff *skb, u32 vxflags)
{
        struct vxlanhdr_gpe *gpe = (struct vxlanhdr_gpe *)unparsed;

        /* Need to have Next Protocol set for interfaces in GPE mode. */
        if (!gpe->np_applied)
                return false;
        /* "The initial version is 0. If a receiver does not support the
         * version indicated it MUST drop the packet.
         */
        if (gpe->version != 0)
                return false;
        /* "When the O bit is set to 1, the packet is an OAM packet and OAM
         * processing MUST occur." However, we don't implement OAM
         * processing, thus drop the packet.
         */
        if (gpe->oam_flag)
                return false;

        *protocol = tun_p_to_eth_p(gpe->next_protocol);
        if (!*protocol)
                return false;

        unparsed->vx_flags &= ~VXLAN_GPE_USED_BITS;
        return true;
}

static bool vxlan_set_mac(struct vxlan_dev *vxlan,
                          struct vxlan_sock *vs,
                          struct sk_buff *skb, __be32 vni)
{
        union vxlan_addr saddr;
        u32 ifindex = skb->dev->ifindex;

        skb_reset_mac_header(skb);
        skb->protocol = eth_type_trans(skb, vxlan->dev);
        skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);

        /* Ignore packet loops (and multicast echo) */
        if (ether_addr_equal(eth_hdr(skb)->h_source, vxlan->dev->dev_addr))
                return false;

        /* Get address from the outer IP header */
        if (vxlan_get_sk_family(vs) == AF_INET) {
                saddr.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
                saddr.sa.sa_family = AF_INET;
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                saddr.sin6.sin6_addr = ipv6_hdr(skb)->saddr;
                saddr.sa.sa_family = AF_INET6;
#endif
        }

        if ((vxlan->cfg.flags & VXLAN_F_LEARN) &&
            vxlan_snoop(skb->dev, &saddr, eth_hdr(skb)->h_source, ifindex, vni))
                return false;

        return true;
}

static bool vxlan_ecn_decapsulate(struct vxlan_sock *vs, void *oiph,
                                  struct sk_buff *skb)
{
        int err = 0;

        if (vxlan_get_sk_family(vs) == AF_INET)
                err = IP_ECN_decapsulate(oiph, skb);
#if IS_ENABLED(CONFIG_IPV6)
        else
                err = IP6_ECN_decapsulate(oiph, skb);
#endif

        if (unlikely(err) && log_ecn_error) {
                if (vxlan_get_sk_family(vs) == AF_INET)
                        net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
                                             &((struct iphdr *)oiph)->saddr,
                                             ((struct iphdr *)oiph)->tos);
                else
                        net_info_ratelimited("non-ECT from %pI6\n",
                                             &((struct ipv6hdr *)oiph)->saddr);
        }
        return err <= 1;
}

/* Callback from net/ipv4/udp.c to receive packets */
static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
{
        struct vxlan_dev *vxlan;
        struct vxlan_sock *vs;
        struct vxlanhdr unparsed;
        struct vxlan_metadata _md;
        struct vxlan_metadata *md = &_md;
        __be16 protocol = htons(ETH_P_TEB);
        bool raw_proto = false;
        void *oiph;
        __be32 vni = 0;

        /* Need UDP and VXLAN header to be present */
        if (!pskb_may_pull(skb, VXLAN_HLEN))
                goto drop;

        unparsed = *vxlan_hdr(skb);
        /* VNI flag always required to be set */
        if (!(unparsed.vx_flags & VXLAN_HF_VNI)) {
                netdev_dbg(skb->dev, "invalid vxlan flags=%#x vni=%#x\n",
                           ntohl(vxlan_hdr(skb)->vx_flags),
                           ntohl(vxlan_hdr(skb)->vx_vni));
                /* Return non vxlan pkt */
                goto drop;
        }
        unparsed.vx_flags &= ~VXLAN_HF_VNI;
        unparsed.vx_vni &= ~VXLAN_VNI_MASK;

        vs = rcu_dereference_sk_user_data(sk);
        if (!vs)
                goto drop;

        vni = vxlan_vni(vxlan_hdr(skb)->vx_vni);

        vxlan = vxlan_vs_find_vni(vs, skb->dev->ifindex, vni);
        if (!vxlan)
                goto drop;

        /* For backwards compatibility, only allow reserved fields to be
         * used by VXLAN extensions if explicitly requested.
         */
        if (vs->flags & VXLAN_F_GPE) {
                if (!vxlan_parse_gpe_hdr(&unparsed, &protocol, skb, vs->flags))
                        goto drop;
                raw_proto = true;
        }

        if (__iptunnel_pull_header(skb, VXLAN_HLEN, protocol, raw_proto,
                                   !net_eq(vxlan->net, dev_net(vxlan->dev))))
                goto drop;

        if (vs->flags & VXLAN_F_REMCSUM_RX)
                if (unlikely(!vxlan_remcsum(&unparsed, skb, vs->flags)))
                        goto drop;

        if (vxlan_collect_metadata(vs)) {
                struct metadata_dst *tun_dst;

                tun_dst = udp_tun_rx_dst(skb, vxlan_get_sk_family(vs), TUNNEL_KEY,
                                         key32_to_tunnel_id(vni), sizeof(*md));

                if (!tun_dst)
                        goto drop;

                md = ip_tunnel_info_opts(&tun_dst->u.tun_info);

                skb_dst_set(skb, (struct dst_entry *)tun_dst);
        } else {
                memset(md, 0, sizeof(*md));
        }

        if (vs->flags & VXLAN_F_GBP)
                vxlan_parse_gbp_hdr(&unparsed, skb, vs->flags, md);
        /* Note that GBP and GPE can never be active together. This is
         * ensured in vxlan_dev_configure.
         */

        if (unparsed.vx_flags || unparsed.vx_vni) {
                /* If there are any unprocessed flags remaining treat
                 * this as a malformed packet. This behavior diverges from
                 * VXLAN RFC (RFC7348) which stipulates that bits in reserved
                 * in reserved fields are to be ignored. The approach here
                 * maintains compatibility with previous stack code, and also
                 * is more robust and provides a little more security in
                 * adding extensions to VXLAN.
                 */
                goto drop;
        }

        if (!raw_proto) {
                if (!vxlan_set_mac(vxlan, vs, skb, vni))
                        goto drop;
        } else {
                skb_reset_mac_header(skb);
                skb->dev = vxlan->dev;
                skb->pkt_type = PACKET_HOST;
        }

        oiph = skb_network_header(skb);
        skb_reset_network_header(skb);

        if (!vxlan_ecn_decapsulate(vs, oiph, skb)) {
                ++vxlan->dev->stats.rx_frame_errors;
                ++vxlan->dev->stats.rx_errors;
                goto drop;
        }

        rcu_read_lock();

        if (unlikely(!(vxlan->dev->flags & IFF_UP))) {
                rcu_read_unlock();
                atomic_long_inc(&vxlan->dev->rx_dropped);
                goto drop;
        }

        dev_sw_netstats_rx_add(vxlan->dev, skb->len);
        gro_cells_receive(&vxlan->gro_cells, skb);

        rcu_read_unlock();

        return 0;

drop:
        /* Consume bad packet */
        kfree_skb(skb);
        return 0;
}

/* Callback from net/ipv{4,6}/udp.c to check that we have a VNI for errors */
static int vxlan_err_lookup(struct sock *sk, struct sk_buff *skb)
{
        struct vxlan_dev *vxlan;
        struct vxlan_sock *vs;
        struct vxlanhdr *hdr;
        __be32 vni;

        if (!pskb_may_pull(skb, skb_transport_offset(skb) + VXLAN_HLEN))
                return -EINVAL;

        hdr = vxlan_hdr(skb);

        if (!(hdr->vx_flags & VXLAN_HF_VNI))
                return -EINVAL;

        vs = rcu_dereference_sk_user_data(sk);
        if (!vs)
                return -ENOENT;

        vni = vxlan_vni(hdr->vx_vni);
        vxlan = vxlan_vs_find_vni(vs, skb->dev->ifindex, vni);
        if (!vxlan)
                return -ENOENT;

        return 0;
}

static int arp_reduce(struct net_device *dev, struct sk_buff *skb, __be32 vni)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct arphdr *parp;
        u8 *arpptr, *sha;
        __be32 sip, tip;
        struct neighbour *n;

        if (dev->flags & IFF_NOARP)
                goto out;

        if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
                dev->stats.tx_dropped++;
                goto out;
        }
        parp = arp_hdr(skb);

        if ((parp->ar_hrd != htons(ARPHRD_ETHER) &&
             parp->ar_hrd != htons(ARPHRD_IEEE802)) ||
            parp->ar_pro != htons(ETH_P_IP) ||
            parp->ar_op != htons(ARPOP_REQUEST) ||
            parp->ar_hln != dev->addr_len ||
            parp->ar_pln != 4)
                goto out;
        arpptr = (u8 *)parp + sizeof(struct arphdr);
        sha = arpptr;
        arpptr += dev->addr_len;        /* sha */
        memcpy(&sip, arpptr, sizeof(sip));
        arpptr += sizeof(sip);
        arpptr += dev->addr_len;        /* tha */
        memcpy(&tip, arpptr, sizeof(tip));

        if (ipv4_is_loopback(tip) ||
            ipv4_is_multicast(tip))
                goto out;

        n = neigh_lookup(&arp_tbl, &tip, dev);

        if (n) {
                struct vxlan_fdb *f;
                struct sk_buff  *reply;

                if (!(n->nud_state & NUD_CONNECTED)) {
                        neigh_release(n);
                        goto out;
                }

                f = vxlan_find_mac(vxlan, n->ha, vni);
                if (f && vxlan_addr_any(&(first_remote_rcu(f)->remote_ip))) {
                        /* bridge-local neighbor */
                        neigh_release(n);
                        goto out;
                }

                reply = arp_create(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
                                n->ha, sha);

                neigh_release(n);

                if (reply == NULL)
                        goto out;

                skb_reset_mac_header(reply);
                __skb_pull(reply, skb_network_offset(reply));
                reply->ip_summed = CHECKSUM_UNNECESSARY;
                reply->pkt_type = PACKET_HOST;

                if (netif_rx_ni(reply) == NET_RX_DROP)
                        dev->stats.rx_dropped++;
        } else if (vxlan->cfg.flags & VXLAN_F_L3MISS) {
                union vxlan_addr ipa = {
                        .sin.sin_addr.s_addr = tip,
                        .sin.sin_family = AF_INET,
                };

                vxlan_ip_miss(dev, &ipa);
        }
out:
        consume_skb(skb);
        return NETDEV_TX_OK;
}

#if IS_ENABLED(CONFIG_IPV6)
static struct sk_buff *vxlan_na_create(struct sk_buff *request,
        struct neighbour *n, bool isrouter)
{
        struct net_device *dev = request->dev;
        struct sk_buff *reply;
        struct nd_msg *ns, *na;
        struct ipv6hdr *pip6;
        u8 *daddr;
        int na_olen = 8; /* opt hdr + ETH_ALEN for target */
        int ns_olen;
        int i, len;

        if (dev == NULL || !pskb_may_pull(request, request->len))
                return NULL;

        len = LL_RESERVED_SPACE(dev) + sizeof(struct ipv6hdr) +
                sizeof(*na) + na_olen + dev->needed_tailroom;
        reply = alloc_skb(len, GFP_ATOMIC);
        if (reply == NULL)
                return NULL;

        reply->protocol = htons(ETH_P_IPV6);
        reply->dev = dev;
        skb_reserve(reply, LL_RESERVED_SPACE(request->dev));
        skb_push(reply, sizeof(struct ethhdr));
        skb_reset_mac_header(reply);

        ns = (struct nd_msg *)(ipv6_hdr(request) + 1);

        daddr = eth_hdr(request)->h_source;
        ns_olen = request->len - skb_network_offset(request) -
                sizeof(struct ipv6hdr) - sizeof(*ns);
        for (i = 0; i < ns_olen-1; i += (ns->opt[i+1]<<3)) {
                if (!ns->opt[i + 1]) {
                        kfree_skb(reply);
                        return NULL;
                }
                if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) {
                        daddr = ns->opt + i + sizeof(struct nd_opt_hdr);
                        break;
                }
        }

        /* Ethernet header */
        ether_addr_copy(eth_hdr(reply)->h_dest, daddr);
        ether_addr_copy(eth_hdr(reply)->h_source, n->ha);
        eth_hdr(reply)->h_proto = htons(ETH_P_IPV6);
        reply->protocol = htons(ETH_P_IPV6);

        skb_pull(reply, sizeof(struct ethhdr));
        skb_reset_network_header(reply);
        skb_put(reply, sizeof(struct ipv6hdr));

        /* IPv6 header */

        pip6 = ipv6_hdr(reply);
        memset(pip6, 0, sizeof(struct ipv6hdr));
        pip6->version = 6;
        pip6->priority = ipv6_hdr(request)->priority;
        pip6->nexthdr = IPPROTO_ICMPV6;
        pip6->hop_limit = 255;
        pip6->daddr = ipv6_hdr(request)->saddr;
        pip6->saddr = *(struct in6_addr *)n->primary_key;

        skb_pull(reply, sizeof(struct ipv6hdr));
        skb_reset_transport_header(reply);

        /* Neighbor Advertisement */
        na = skb_put_zero(reply, sizeof(*na) + na_olen);
        na->icmph.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
        na->icmph.icmp6_router = isrouter;
        na->icmph.icmp6_override = 1;
        na->icmph.icmp6_solicited = 1;
        na->target = ns->target;
        ether_addr_copy(&na->opt[2], n->ha);
        na->opt[0] = ND_OPT_TARGET_LL_ADDR;
        na->opt[1] = na_olen >> 3;

        na->icmph.icmp6_cksum = csum_ipv6_magic(&pip6->saddr,
                &pip6->daddr, sizeof(*na)+na_olen, IPPROTO_ICMPV6,
                csum_partial(na, sizeof(*na)+na_olen, 0));

        pip6->payload_len = htons(sizeof(*na)+na_olen);

        skb_push(reply, sizeof(struct ipv6hdr));

        reply->ip_summed = CHECKSUM_UNNECESSARY;

        return reply;
}

static int neigh_reduce(struct net_device *dev, struct sk_buff *skb, __be32 vni)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        const struct in6_addr *daddr;
        const struct ipv6hdr *iphdr;
        struct inet6_dev *in6_dev;
        struct neighbour *n;
        struct nd_msg *msg;

        rcu_read_lock();
        in6_dev = __in6_dev_get(dev);
        if (!in6_dev)
                goto out;

        iphdr = ipv6_hdr(skb);
        daddr = &iphdr->daddr;
        msg = (struct nd_msg *)(iphdr + 1);

        if (ipv6_addr_loopback(daddr) ||
            ipv6_addr_is_multicast(&msg->target))
                goto out;

        n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, dev);

        if (n) {
                struct vxlan_fdb *f;
                struct sk_buff *reply;

                if (!(n->nud_state & NUD_CONNECTED)) {
                        neigh_release(n);
                        goto out;
                }

                f = vxlan_find_mac(vxlan, n->ha, vni);
                if (f && vxlan_addr_any(&(first_remote_rcu(f)->remote_ip))) {
                        /* bridge-local neighbor */
                        neigh_release(n);
                        goto out;
                }

                reply = vxlan_na_create(skb, n,
                                        !!(f ? f->flags & NTF_ROUTER : 0));

                neigh_release(n);

                if (reply == NULL)
                        goto out;

                if (netif_rx_ni(reply) == NET_RX_DROP)
                        dev->stats.rx_dropped++;

        } else if (vxlan->cfg.flags & VXLAN_F_L3MISS) {
                union vxlan_addr ipa = {
                        .sin6.sin6_addr = msg->target,
                        .sin6.sin6_family = AF_INET6,
                };

                vxlan_ip_miss(dev, &ipa);
        }

out:
        rcu_read_unlock();
        consume_skb(skb);
        return NETDEV_TX_OK;
}
#endif

static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct neighbour *n;

        if (is_multicast_ether_addr(eth_hdr(skb)->h_dest))
                return false;

        n = NULL;
        switch (ntohs(eth_hdr(skb)->h_proto)) {
        case ETH_P_IP:
        {
                struct iphdr *pip;

                if (!pskb_may_pull(skb, sizeof(struct iphdr)))
                        return false;
                pip = ip_hdr(skb);
                n = neigh_lookup(&arp_tbl, &pip->daddr, dev);
                if (!n && (vxlan->cfg.flags & VXLAN_F_L3MISS)) {
                        union vxlan_addr ipa = {
                                .sin.sin_addr.s_addr = pip->daddr,
                                .sin.sin_family = AF_INET,
                        };

                        vxlan_ip_miss(dev, &ipa);
                        return false;
                }

                break;
        }
#if IS_ENABLED(CONFIG_IPV6)
        case ETH_P_IPV6:
        {
                struct ipv6hdr *pip6;

                if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
                        return false;
                pip6 = ipv6_hdr(skb);
                n = neigh_lookup(ipv6_stub->nd_tbl, &pip6->daddr, dev);
                if (!n && (vxlan->cfg.flags & VXLAN_F_L3MISS)) {
                        union vxlan_addr ipa = {
                                .sin6.sin6_addr = pip6->daddr,
                                .sin6.sin6_family = AF_INET6,
                        };

                        vxlan_ip_miss(dev, &ipa);
                        return false;
                }

                break;
        }
#endif
        default:
                return false;
        }

        if (n) {
                bool diff;

                diff = !ether_addr_equal(eth_hdr(skb)->h_dest, n->ha);
                if (diff) {
                        memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
                                dev->addr_len);
                        memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len);
                }
                neigh_release(n);
                return diff;
        }

        return false;
}

static void vxlan_build_gbp_hdr(struct vxlanhdr *vxh, u32 vxflags,
                                struct vxlan_metadata *md)
{
        struct vxlanhdr_gbp *gbp;

        if (!md->gbp)
                return;

        gbp = (struct vxlanhdr_gbp *)vxh;
        vxh->vx_flags |= VXLAN_HF_GBP;

        if (md->gbp & VXLAN_GBP_DONT_LEARN)
                gbp->dont_learn = 1;

        if (md->gbp & VXLAN_GBP_POLICY_APPLIED)
                gbp->policy_applied = 1;

        gbp->policy_id = htons(md->gbp & VXLAN_GBP_ID_MASK);
}

static int vxlan_build_gpe_hdr(struct vxlanhdr *vxh, u32 vxflags,
                               __be16 protocol)
{
        struct vxlanhdr_gpe *gpe = (struct vxlanhdr_gpe *)vxh;

        gpe->np_applied = 1;
        gpe->next_protocol = tun_p_from_eth_p(protocol);
        if (!gpe->next_protocol)
                return -EPFNOSUPPORT;
        return 0;
}

static int vxlan_build_skb(struct sk_buff *skb, struct dst_entry *dst,
                           int iphdr_len, __be32 vni,
                           struct vxlan_metadata *md, u32 vxflags,
                           bool udp_sum)
{
        struct vxlanhdr *vxh;
        int min_headroom;
        int err;
        int type = udp_sum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
        __be16 inner_protocol = htons(ETH_P_TEB);

        if ((vxflags & VXLAN_F_REMCSUM_TX) &&
            skb->ip_summed == CHECKSUM_PARTIAL) {
                int csum_start = skb_checksum_start_offset(skb);

                if (csum_start <= VXLAN_MAX_REMCSUM_START &&
                    !(csum_start & VXLAN_RCO_SHIFT_MASK) &&
                    (skb->csum_offset == offsetof(struct udphdr, check) ||
                     skb->csum_offset == offsetof(struct tcphdr, check)))
                        type |= SKB_GSO_TUNNEL_REMCSUM;
        }

        min_headroom = LL_RESERVED_SPACE(dst->dev) + dst->header_len
                        + VXLAN_HLEN + iphdr_len;

        /* Need space for new headers (invalidates iph ptr) */
        err = skb_cow_head(skb, min_headroom);
        if (unlikely(err))
                return err;

        err = iptunnel_handle_offloads(skb, type);
        if (err)
                return err;

        vxh = __skb_push(skb, sizeof(*vxh));
        vxh->vx_flags = VXLAN_HF_VNI;
        vxh->vx_vni = vxlan_vni_field(vni);

        if (type & SKB_GSO_TUNNEL_REMCSUM) {
                unsigned int start;

                start = skb_checksum_start_offset(skb) - sizeof(struct vxlanhdr);
                vxh->vx_vni |= vxlan_compute_rco(start, skb->csum_offset);
                vxh->vx_flags |= VXLAN_HF_RCO;

                if (!skb_is_gso(skb)) {
                        skb->ip_summed = CHECKSUM_NONE;
                        skb->encapsulation = 0;
                }
        }

        if (vxflags & VXLAN_F_GBP)
                vxlan_build_gbp_hdr(vxh, vxflags, md);
        if (vxflags & VXLAN_F_GPE) {
                err = vxlan_build_gpe_hdr(vxh, vxflags, skb->protocol);
                if (err < 0)
                        return err;
                inner_protocol = skb->protocol;
        }

        skb_set_inner_protocol(skb, inner_protocol);
        return 0;
}

static struct rtable *vxlan_get_route(struct vxlan_dev *vxlan, struct net_device *dev,
                                      struct vxlan_sock *sock4,
                                      struct sk_buff *skb, int oif, u8 tos,
                                      __be32 daddr, __be32 *saddr, __be16 dport, __be16 sport,
                                      struct dst_cache *dst_cache,
                                      const struct ip_tunnel_info *info)
{
        bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
        struct rtable *rt = NULL;
        struct flowi4 fl4;

        if (!sock4)
                return ERR_PTR(-EIO);

        if (tos && !info)
                use_cache = false;
        if (use_cache) {
                rt = dst_cache_get_ip4(dst_cache, saddr);
                if (rt)
                        return rt;
        }

        memset(&fl4, 0, sizeof(fl4));
        fl4.flowi4_oif = oif;
        fl4.flowi4_tos = RT_TOS(tos);
        fl4.flowi4_mark = skb->mark;
        fl4.flowi4_proto = IPPROTO_UDP;
        fl4.daddr = daddr;
        fl4.saddr = *saddr;
        fl4.fl4_dport = dport;
        fl4.fl4_sport = sport;

        rt = ip_route_output_key(vxlan->net, &fl4);
        if (!IS_ERR(rt)) {
                if (rt->dst.dev == dev) {
                        netdev_dbg(dev, "circular route to %pI4\n", &daddr);
                        ip_rt_put(rt);
                        return ERR_PTR(-ELOOP);
                }

                *saddr = fl4.saddr;
                if (use_cache)
                        dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
        } else {
                netdev_dbg(dev, "no route to %pI4\n", &daddr);
                return ERR_PTR(-ENETUNREACH);
        }
        return rt;
}

#if IS_ENABLED(CONFIG_IPV6)
static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
                                          struct net_device *dev,
                                          struct vxlan_sock *sock6,
                                          struct sk_buff *skb, int oif, u8 tos,
                                          __be32 label,
                                          const struct in6_addr *daddr,
                                          struct in6_addr *saddr,
                                          __be16 dport, __be16 sport,
                                          struct dst_cache *dst_cache,
                                          const struct ip_tunnel_info *info)
{
        bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
        struct dst_entry *ndst;
        struct flowi6 fl6;

        if (!sock6)
                return ERR_PTR(-EIO);

        if (tos && !info)
                use_cache = false;
        if (use_cache) {
                ndst = dst_cache_get_ip6(dst_cache, saddr);
                if (ndst)
                        return ndst;
        }

        memset(&fl6, 0, sizeof(fl6));
        fl6.flowi6_oif = oif;
        fl6.daddr = *daddr;
        fl6.saddr = *saddr;
        fl6.flowlabel = ip6_make_flowinfo(RT_TOS(tos), label);
        fl6.flowi6_mark = skb->mark;
        fl6.flowi6_proto = IPPROTO_UDP;
        fl6.fl6_dport = dport;
        fl6.fl6_sport = sport;

        ndst = ipv6_stub->ipv6_dst_lookup_flow(vxlan->net, sock6->sock->sk,
                                               &fl6, NULL);
        if (IS_ERR(ndst)) {
                netdev_dbg(dev, "no route to %pI6\n", daddr);
                return ERR_PTR(-ENETUNREACH);
        }

        if (unlikely(ndst->dev == dev)) {
                netdev_dbg(dev, "circular route to %pI6\n", daddr);
                dst_release(ndst);
                return ERR_PTR(-ELOOP);
        }

        *saddr = fl6.saddr;
        if (use_cache)
                dst_cache_set_ip6(dst_cache, ndst, saddr);
        return ndst;
}
#endif

/* Bypass encapsulation if the destination is local */
static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan,
                               struct vxlan_dev *dst_vxlan, __be32 vni,
                               bool snoop)
{
        struct pcpu_sw_netstats *tx_stats, *rx_stats;
        union vxlan_addr loopback;
        union vxlan_addr *remote_ip = &dst_vxlan->default_dst.remote_ip;
        struct net_device *dev;
        int len = skb->len;

        tx_stats = this_cpu_ptr(src_vxlan->dev->tstats);
        rx_stats = this_cpu_ptr(dst_vxlan->dev->tstats);
        skb->pkt_type = PACKET_HOST;
        skb->encapsulation = 0;
        skb->dev = dst_vxlan->dev;
        __skb_pull(skb, skb_network_offset(skb));

        if (remote_ip->sa.sa_family == AF_INET) {
                loopback.sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
                loopback.sa.sa_family =  AF_INET;
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                loopback.sin6.sin6_addr = in6addr_loopback;
                loopback.sa.sa_family =  AF_INET6;
#endif
        }

        rcu_read_lock();
        dev = skb->dev;
        if (unlikely(!(dev->flags & IFF_UP))) {
                kfree_skb(skb);
                goto drop;
        }

        if ((dst_vxlan->cfg.flags & VXLAN_F_LEARN) && snoop)
                vxlan_snoop(dev, &loopback, eth_hdr(skb)->h_source, 0, vni);

        u64_stats_update_begin(&tx_stats->syncp);
        tx_stats->tx_packets++;
        tx_stats->tx_bytes += len;
        u64_stats_update_end(&tx_stats->syncp);

        if (netif_rx(skb) == NET_RX_SUCCESS) {
                u64_stats_update_begin(&rx_stats->syncp);
                rx_stats->rx_packets++;
                rx_stats->rx_bytes += len;
                u64_stats_update_end(&rx_stats->syncp);
        } else {
drop:
                dev->stats.rx_dropped++;
        }
        rcu_read_unlock();
}

static int encap_bypass_if_local(struct sk_buff *skb, struct net_device *dev,
                                 struct vxlan_dev *vxlan,
                                 union vxlan_addr *daddr,
                                 __be16 dst_port, int dst_ifindex, __be32 vni,
                                 struct dst_entry *dst,
                                 u32 rt_flags)
{
#if IS_ENABLED(CONFIG_IPV6)
        /* IPv6 rt-flags are checked against RTF_LOCAL, but the value of
         * RTF_LOCAL is equal to RTCF_LOCAL. So to keep code simple
         * we can use RTCF_LOCAL which works for ipv4 and ipv6 route entry.
         */
        BUILD_BUG_ON(RTCF_LOCAL != RTF_LOCAL);
#endif
        /* Bypass encapsulation if the destination is local */
        if (rt_flags & RTCF_LOCAL &&
            !(rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))) {
                struct vxlan_dev *dst_vxlan;

                dst_release(dst);
                dst_vxlan = vxlan_find_vni(vxlan->net, dst_ifindex, vni,
                                           daddr->sa.sa_family, dst_port,
                                           vxlan->cfg.flags);
                if (!dst_vxlan) {
                        dev->stats.tx_errors++;
                        kfree_skb(skb);

                        return -ENOENT;
                }
                vxlan_encap_bypass(skb, vxlan, dst_vxlan, vni, true);
                return 1;
        }

        return 0;
}

static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                           __be32 default_vni, struct vxlan_rdst *rdst,
                           bool did_rsc)
{
        struct dst_cache *dst_cache;
        struct ip_tunnel_info *info;
        struct vxlan_dev *vxlan = netdev_priv(dev);
        const struct iphdr *old_iph = ip_hdr(skb);
        union vxlan_addr *dst;
        union vxlan_addr remote_ip, local_ip;
        struct vxlan_metadata _md;
        struct vxlan_metadata *md = &_md;
        __be16 src_port = 0, dst_port;
        struct dst_entry *ndst = NULL;
        __be32 vni, label;
        __u8 tos, ttl;
        int ifindex;
        int err;
        u32 flags = vxlan->cfg.flags;
        bool udp_sum = false;
        bool xnet = !net_eq(vxlan->net, dev_net(vxlan->dev));

        info = skb_tunnel_info(skb);

        if (rdst) {
                dst = &rdst->remote_ip;
                if (vxlan_addr_any(dst)) {
                        if (did_rsc) {
                                /* short-circuited back to local bridge */
                                vxlan_encap_bypass(skb, vxlan, vxlan,
                                                   default_vni, true);
                                return;
                        }
                        goto drop;
                }

                dst_port = rdst->remote_port ? rdst->remote_port : vxlan->cfg.dst_port;
                vni = (rdst->remote_vni) ? : default_vni;
                ifindex = rdst->remote_ifindex;
                local_ip = vxlan->cfg.saddr;
                dst_cache = &rdst->dst_cache;
                md->gbp = skb->mark;
                if (flags & VXLAN_F_TTL_INHERIT) {
                        ttl = ip_tunnel_get_ttl(old_iph, skb);
                } else {
                        ttl = vxlan->cfg.ttl;
                        if (!ttl && vxlan_addr_multicast(dst))
                                ttl = 1;
                }

                tos = vxlan->cfg.tos;
                if (tos == 1)
                        tos = ip_tunnel_get_dsfield(old_iph, skb);

                if (dst->sa.sa_family == AF_INET)
                        udp_sum = !(flags & VXLAN_F_UDP_ZERO_CSUM_TX);
                else
                        udp_sum = !(flags & VXLAN_F_UDP_ZERO_CSUM6_TX);
                label = vxlan->cfg.label;
        } else {
                if (!info) {
                        WARN_ONCE(1, "%s: Missing encapsulation instructions\n",
                                  dev->name);
                        goto drop;
                }
                remote_ip.sa.sa_family = ip_tunnel_info_af(info);
                if (remote_ip.sa.sa_family == AF_INET) {
                        remote_ip.sin.sin_addr.s_addr = info->key.u.ipv4.dst;
                        local_ip.sin.sin_addr.s_addr = info->key.u.ipv4.src;
                } else {
                        remote_ip.sin6.sin6_addr = info->key.u.ipv6.dst;
                        local_ip.sin6.sin6_addr = info->key.u.ipv6.src;
                }
                dst = &remote_ip;
                dst_port = info->key.tp_dst ? : vxlan->cfg.dst_port;
                vni = tunnel_id_to_key32(info->key.tun_id);
                ifindex = 0;
                dst_cache = &info->dst_cache;
                if (info->key.tun_flags & TUNNEL_VXLAN_OPT) {
                        if (info->options_len < sizeof(*md))
                                goto drop;
                        md = ip_tunnel_info_opts(info);
                }
                ttl = info->key.ttl;
                tos = info->key.tos;
                label = info->key.label;
                udp_sum = !!(info->key.tun_flags & TUNNEL_CSUM);
        }
        src_port = udp_flow_src_port(dev_net(dev), skb, vxlan->cfg.port_min,
                                     vxlan->cfg.port_max, true);

        rcu_read_lock();
        if (dst->sa.sa_family == AF_INET) {
                struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock);
                struct rtable *rt;
                __be16 df = 0;

                if (!ifindex)
                        ifindex = sock4->sock->sk->sk_bound_dev_if;

                rt = vxlan_get_route(vxlan, dev, sock4, skb, ifindex, tos,
                                     dst->sin.sin_addr.s_addr,
                                     &local_ip.sin.sin_addr.s_addr,
                                     dst_port, src_port,
                                     dst_cache, info);
                if (IS_ERR(rt)) {
                        err = PTR_ERR(rt);
                        goto tx_error;
                }

                if (!info) {
                        /* Bypass encapsulation if the destination is local */
                        err = encap_bypass_if_local(skb, dev, vxlan, dst,
                                                    dst_port, ifindex, vni,
                                                    &rt->dst, rt->rt_flags);
                        if (err)
                                goto out_unlock;

                        if (vxlan->cfg.df == VXLAN_DF_SET) {
                                df = htons(IP_DF);
                        } else if (vxlan->cfg.df == VXLAN_DF_INHERIT) {
                                struct ethhdr *eth = eth_hdr(skb);

                                if (ntohs(eth->h_proto) == ETH_P_IPV6 ||
                                    (ntohs(eth->h_proto) == ETH_P_IP &&
                                     old_iph->frag_off & htons(IP_DF)))
                                        df = htons(IP_DF);
                        }
                } else if (info->key.tun_flags & TUNNEL_DONT_FRAGMENT) {
                        df = htons(IP_DF);
                }

                ndst = &rt->dst;
                err = skb_tunnel_check_pmtu(skb, ndst, VXLAN_HEADROOM,
                                            netif_is_any_bridge_port(dev));
                if (err < 0) {
                        goto tx_error;
                } else if (err) {
                        if (info) {
                                struct ip_tunnel_info *unclone;
                                struct in_addr src, dst;

                                unclone = skb_tunnel_info_unclone(skb);
                                if (unlikely(!unclone))
                                        goto tx_error;

                                src = remote_ip.sin.sin_addr;
                                dst = local_ip.sin.sin_addr;
                                unclone->key.u.ipv4.src = src.s_addr;
                                unclone->key.u.ipv4.dst = dst.s_addr;
                        }
                        vxlan_encap_bypass(skb, vxlan, vxlan, vni, false);
                        dst_release(ndst);
                        goto out_unlock;
                }

                tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
                ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);
                err = vxlan_build_skb(skb, ndst, sizeof(struct iphdr),
                                      vni, md, flags, udp_sum);
                if (err < 0)
                        goto tx_error;

                udp_tunnel_xmit_skb(rt, sock4->sock->sk, skb, local_ip.sin.sin_addr.s_addr,
                                    dst->sin.sin_addr.s_addr, tos, ttl, df,
                                    src_port, dst_port, xnet, !udp_sum);
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock);

                if (!ifindex)
                        ifindex = sock6->sock->sk->sk_bound_dev_if;

                ndst = vxlan6_get_route(vxlan, dev, sock6, skb, ifindex, tos,
                                        label, &dst->sin6.sin6_addr,
                                        &local_ip.sin6.sin6_addr,
                                        dst_port, src_port,
                                        dst_cache, info);
                if (IS_ERR(ndst)) {
                        err = PTR_ERR(ndst);
                        ndst = NULL;
                        goto tx_error;
                }

                if (!info) {
                        u32 rt6i_flags = ((struct rt6_info *)ndst)->rt6i_flags;

                        err = encap_bypass_if_local(skb, dev, vxlan, dst,
                                                    dst_port, ifindex, vni,
                                                    ndst, rt6i_flags);
                        if (err)
                                goto out_unlock;
                }

                err = skb_tunnel_check_pmtu(skb, ndst, VXLAN6_HEADROOM,
                                            netif_is_any_bridge_port(dev));
                if (err < 0) {
                        goto tx_error;
                } else if (err) {
                        if (info) {
                                struct ip_tunnel_info *unclone;
                                struct in6_addr src, dst;

                                unclone = skb_tunnel_info_unclone(skb);
                                if (unlikely(!unclone))
                                        goto tx_error;

                                src = remote_ip.sin6.sin6_addr;
                                dst = local_ip.sin6.sin6_addr;
                                unclone->key.u.ipv6.src = src;
                                unclone->key.u.ipv6.dst = dst;
                        }

                        vxlan_encap_bypass(skb, vxlan, vxlan, vni, false);
                        dst_release(ndst);
                        goto out_unlock;
                }

                tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
                ttl = ttl ? : ip6_dst_hoplimit(ndst);
                skb_scrub_packet(skb, xnet);
                err = vxlan_build_skb(skb, ndst, sizeof(struct ipv6hdr),
                                      vni, md, flags, udp_sum);
                if (err < 0)
                        goto tx_error;

                udp_tunnel6_xmit_skb(ndst, sock6->sock->sk, skb, dev,
                                     &local_ip.sin6.sin6_addr,
                                     &dst->sin6.sin6_addr, tos, ttl,
                                     label, src_port, dst_port, !udp_sum);
#endif
        }
out_unlock:
        rcu_read_unlock();
        return;

drop:
        dev->stats.tx_dropped++;
        dev_kfree_skb(skb);
        return;

tx_error:
        rcu_read_unlock();
        if (err == -ELOOP)
                dev->stats.collisions++;
        else if (err == -ENETUNREACH)
                dev->stats.tx_carrier_errors++;
        dst_release(ndst);
        dev->stats.tx_errors++;
        kfree_skb(skb);
}

static void vxlan_xmit_nh(struct sk_buff *skb, struct net_device *dev,
                          struct vxlan_fdb *f, __be32 vni, bool did_rsc)
{
        struct vxlan_rdst nh_rdst;
        struct nexthop *nh;
        bool do_xmit;
        u32 hash;

        memset(&nh_rdst, 0, sizeof(struct vxlan_rdst));
        hash = skb_get_hash(skb);

        rcu_read_lock();
        nh = rcu_dereference(f->nh);
        if (!nh) {
                rcu_read_unlock();
                goto drop;
        }
        do_xmit = vxlan_fdb_nh_path_select(nh, hash, &nh_rdst);
        rcu_read_unlock();

        if (likely(do_xmit))
                vxlan_xmit_one(skb, dev, vni, &nh_rdst, did_rsc);
        else
                goto drop;

        return;

drop:
        dev->stats.tx_dropped++;
        dev_kfree_skb(skb);
}

/* Transmit local packets over Vxlan
 *
 * Outer IP header inherits ECN and DF from inner header.
 * Outer UDP destination is the VXLAN assigned port.
 *           source port is based on hash of flow
 */
static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_rdst *rdst, *fdst = NULL;
        const struct ip_tunnel_info *info;
        bool did_rsc = false;
        struct vxlan_fdb *f;
        struct ethhdr *eth;
        __be32 vni = 0;

        info = skb_tunnel_info(skb);

        skb_reset_mac_header(skb);

        if (vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA) {
                if (info && info->mode & IP_TUNNEL_INFO_BRIDGE &&
                    info->mode & IP_TUNNEL_INFO_TX) {
                        vni = tunnel_id_to_key32(info->key.tun_id);
                } else {
                        if (info && info->mode & IP_TUNNEL_INFO_TX)
                                vxlan_xmit_one(skb, dev, vni, NULL, false);
                        else
                                kfree_skb(skb);
                        return NETDEV_TX_OK;
                }
        }

        if (vxlan->cfg.flags & VXLAN_F_PROXY) {
                eth = eth_hdr(skb);
                if (ntohs(eth->h_proto) == ETH_P_ARP)
                        return arp_reduce(dev, skb, vni);
#if IS_ENABLED(CONFIG_IPV6)
                else if (ntohs(eth->h_proto) == ETH_P_IPV6 &&
                         pskb_may_pull(skb, sizeof(struct ipv6hdr) +
                                            sizeof(struct nd_msg)) &&
                         ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
                        struct nd_msg *m = (struct nd_msg *)(ipv6_hdr(skb) + 1);

                        if (m->icmph.icmp6_code == 0 &&
                            m->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION)
                                return neigh_reduce(dev, skb, vni);
                }
#endif
        }

        eth = eth_hdr(skb);
        f = vxlan_find_mac(vxlan, eth->h_dest, vni);
        did_rsc = false;

        if (f && (f->flags & NTF_ROUTER) && (vxlan->cfg.flags & VXLAN_F_RSC) &&
            (ntohs(eth->h_proto) == ETH_P_IP ||
             ntohs(eth->h_proto) == ETH_P_IPV6)) {
                did_rsc = route_shortcircuit(dev, skb);
                if (did_rsc)
                        f = vxlan_find_mac(vxlan, eth->h_dest, vni);
        }

        if (f == NULL) {
                f = vxlan_find_mac(vxlan, all_zeros_mac, vni);
                if (f == NULL) {
                        if ((vxlan->cfg.flags & VXLAN_F_L2MISS) &&
                            !is_multicast_ether_addr(eth->h_dest))
                                vxlan_fdb_miss(vxlan, eth->h_dest);

                        dev->stats.tx_dropped++;
                        kfree_skb(skb);
                        return NETDEV_TX_OK;
                }
        }

        if (rcu_access_pointer(f->nh)) {
                vxlan_xmit_nh(skb, dev, f,
                              (vni ? : vxlan->default_dst.remote_vni), did_rsc);
        } else {
                list_for_each_entry_rcu(rdst, &f->remotes, list) {
                        struct sk_buff *skb1;

                        if (!fdst) {
                                fdst = rdst;
                                continue;
                        }
                        skb1 = skb_clone(skb, GFP_ATOMIC);
                        if (skb1)
                                vxlan_xmit_one(skb1, dev, vni, rdst, did_rsc);
                }
                if (fdst)
                        vxlan_xmit_one(skb, dev, vni, fdst, did_rsc);
                else
                        kfree_skb(skb);
        }

        return NETDEV_TX_OK;
}

/* Walk the forwarding table and purge stale entries */
static void vxlan_cleanup(struct timer_list *t)
{
        struct vxlan_dev *vxlan = from_timer(vxlan, t, age_timer);
        unsigned long next_timer = jiffies + FDB_AGE_INTERVAL;
        unsigned int h;

        if (!netif_running(vxlan->dev))
                return;

        for (h = 0; h < FDB_HASH_SIZE; ++h) {
                struct hlist_node *p, *n;

                spin_lock(&vxlan->hash_lock[h]);
                hlist_for_each_safe(p, n, &vxlan->fdb_head[h]) {
                        struct vxlan_fdb *f
                                = container_of(p, struct vxlan_fdb, hlist);
                        unsigned long timeout;

                        if (f->state & (NUD_PERMANENT | NUD_NOARP))
                                continue;

                        if (f->flags & NTF_EXT_LEARNED)
                                continue;

                        timeout = f->used + vxlan->cfg.age_interval * HZ;