/*
 * VXLAN: Virtual eXtensible Local Area Network
 *
 * Copyright (c) 2012-2013 Vyatta Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#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/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>

#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 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;
};

/* 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;
        u8                flags;        /* see ndm_flags */
};

/* 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)
{
        return list_entry_rcu(fdb->remotes.next, struct vxlan_rdst, list);
}

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

/* Find VXLAN socket based on network namespace, address family and UDP port
 * and enabled unshareable flags.
 */
static struct vxlan_sock *vxlan_find_sock(struct net *net, sa_family_t family,
                                          __be16 port, u32 flags)
{
        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)
                        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);
        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;
        struct nlmsghdr *nlh;
        struct ndmsg *ndm;
        bool send_ip, send_eth;

        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;

        if (type == RTM_GETNEIGH) {
                send_ip = !vxlan_addr_any(&rdst->remote_ip);
                send_eth = !is_zero_ether_addr(fdb->eth_addr);
                ndm->ndm_family = send_ip ? rdst->remote_ip.sa.sa_family : AF_INET;
        } else
                ndm->ndm_family = AF_BRIDGE;
        ndm->ndm_state = fdb->state;
        ndm->ndm_ifindex = vxlan->dev->ifindex;
        ndm->ndm_flags = fdb->flags;
        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 (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 ((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;
        if (rdst->remote_ifindex &&
            nla_put_u32(skb, NDA_IFINDEX, rdst->remote_ifindex))
                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_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);
}

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);
}

/* 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);
}

/* Hash chain to use given mac address */
static inline struct hlist_head *vxlan_fdb_head(struct vxlan_dev *vxlan,
                                                const u8 *mac, __be32 vni)
{
        if (vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA)
                return &vxlan->fdb_head[eth_vni_hash(mac, vni)];
        else
                return &vxlan->fdb_head[eth_hash(mac)];
}

/* 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;

        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;
}

/* 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 *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;

        dst_cache_reset(&rd->dst_cache);
        rd->remote_ip = *ip;
        rd->remote_port = port;
        rd->remote_vni = vni;
        rd->remote_ifindex = ifindex;
        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->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 sk_buff **head,
                                          struct sk_buff *skb)
{
        struct sk_buff *p, **pp = NULL;
        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 */

        for (p = *head; p; p = p->next) {
                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_remcsum_cleanup(skb, &grc);
        skb->remcsum_offload = 0;
        NAPI_GRO_CB(skb)->flush |= flush;

        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));
}

/* Add new entry to forwarding table -- assumes lock held */
static int vxlan_fdb_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, __u8 ndm_flags)
{
        struct vxlan_rdst *rd = NULL;
        struct vxlan_fdb *f;
        int notify = 0;
        int rc;

        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;
                }
                if (f->state != state) {
                        f->state = state;
                        f->updated = jiffies;
                        notify = 1;
                }
                if (f->flags != ndm_flags) {
                        f->flags = ndm_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))) {
                                notify |= vxlan_fdb_replace(f, ip, port, vni,
                                                           ifindex);
                        } else
                                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;
                }
        } else {
                if (!(flags & NLM_F_CREATE))
                        return -ENOENT;

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

                /* 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);
                f = kmalloc(sizeof(*f), GFP_ATOMIC);
                if (!f)
                        return -ENOMEM;

                notify = 1;
                f->state = state;
                f->flags = ndm_flags;
                f->updated = f->used = jiffies;
                f->vni = src_vni;
                INIT_LIST_HEAD(&f->remotes);
                memcpy(f->eth_addr, mac, ETH_ALEN);

                rc = vxlan_fdb_append(f, ip, port, vni, ifindex, &rd);
                if (rc < 0) {
                        kfree(f);
                        return rc;
                }

                ++vxlan->addrcnt;
                hlist_add_head_rcu(&f->hlist,
                                   vxlan_fdb_head(vxlan, mac, src_vni));
        }

        if (notify) {
                if (rd == NULL)
                        rd = first_remote_rtnl(f);
                vxlan_fdb_notify(vxlan, f, rd, RTM_NEWNEIGH);
        }

        return 0;
}

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

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

static void vxlan_fdb_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f)
{
        netdev_dbg(vxlan->dev,
                    "delete %pM\n", f->eth_addr);

        --vxlan->addrcnt;
        vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f), RTM_DELNEIGH);

        hlist_del_rcu(&f->hlist);
        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 void vxlan_fdb_dst_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f,
                                  struct vxlan_rdst *rd)
{
        list_del_rcu(&rd->list);
        vxlan_fdb_notify(vxlan, f, rd, RTM_DELNEIGH);
        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)
{
        struct net *net = dev_net(vxlan->dev);
        int err;

        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;
        }

        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 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;
        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[NDA_DST] == NULL)
                return -EINVAL;

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

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

        spin_lock_bh(&vxlan->hash_lock);
        err = vxlan_fdb_create(vxlan, addr, &ip, ndm->ndm_state, flags,
                               port, src_vni, vni, ifindex, ndm->ndm_flags);
        spin_unlock_bh(&vxlan->hash_lock);

        return err;
}

static int __vxlan_fdb_delete(struct vxlan_dev *vxlan,
                              const unsigned char *addr, union vxlan_addr ip,
                              __be16 port, __be32 src_vni, u32 vni, u32 ifindex,
                              u16 vid)
{
        struct vxlan_fdb *f;
        struct vxlan_rdst *rd = NULL;
        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);
                goto out;
        }

        vxlan_fdb_destroy(vxlan, f);

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;
        __be16 port;
        u32 ifindex;
        int err;

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

        spin_lock_bh(&vxlan->hash_lock);
        err = __vxlan_fdb_delete(vxlan, addr, ip, port, src_vni, vni, ifindex,
                                 vid);
        spin_unlock_bh(&vxlan->hash_lock);

        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;

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

                        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)
                                        goto out;
skip:
                                *idx += 1;
                        }
                }
        }
out:
        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;

                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);
        } else {
                /* learned new entry */
                spin_lock(&vxlan->hash_lock);

                /* close off race between vxlan_flush and incoming packets */
                if (netif_running(dev))
                        vxlan_fdb_create(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);
                spin_unlock(&vxlan->hash_lock);
        }

        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 && atomic_read(&sock4->refcnt) == 1)
                return false;
#if IS_ENABLED(CONFIG_IPV6)
        sock6 = rtnl_dereference(dev->vn6_sock);
        if (family == AF_INET6 && sock6 && atomic_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 (!atomic_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 pcpu_sw_netstats *stats;
        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 (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_REMCSUM_RX)
                if (!vxlan_remcsum(&unparsed, skb, vs->flags))
                        goto drop;
        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;
        }

        stats = this_cpu_ptr(vxlan->dev->tstats);
        u64_stats_update_begin(&stats->syncp);
        stats->rx_packets++;
        stats->rx_bytes += skb->len;
        u64_stats_update_end(&stats->syncp);

        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] == 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;

        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:
        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);

        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 (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 (likely(!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;
        int err;

        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;

        err = ipv6_stub->ipv6_dst_lookup(vxlan->net,
                                         sock6->sock->sk,
                                         &ndst, &fl6);
        if (unlikely(err < 0)) {
                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)
{
        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)
                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);
                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);
                                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->options_len &&
                    info->key.tun_flags & TUNNEL_VXLAN_OPT)
                        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;

                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;
                }

                /* Bypass encapsulation if the destination is local */
                if (!info) {
                        err = encap_bypass_if_local(skb, dev, vxlan, dst,
                                                    dst_port, ifindex, vni,
                                                    &rt->dst, rt->rt_flags);
                        if (err)
                                goto out_unlock;
                } else if (info->key.tun_flags & TUNNEL_DONT_FRAGMENT) {
                        df = htons(IP_DF);
                }

                ndst = &rt->dst;
                skb_tunnel_check_pmtu(skb, ndst, VXLAN_HEADROOM);

                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);

                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;
                }

                skb_tunnel_check_pmtu(skb, ndst, VXLAN6_HEADROOM);

                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);
}

/* 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;
                }
        }

        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(unsigned long arg)
{
        struct vxlan_dev *vxlan = (struct vxlan_dev *) arg;
        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_bh(&vxlan->hash_lock);
                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;
                        if (time_before_eq(timeout, jiffies)) {
                                netdev_dbg(vxlan->dev,
                                           "garbage collect %pM\n",
                                           f->eth_addr);
                                f->state = NUD_STALE;
                                vxlan_fdb_destroy(vxlan, f);
                        } else if (time_before(timeout, next_timer))
                                next_timer = timeout;
                }
                spin_unlock_bh(&vxlan->hash_lock);
        }

        mod_timer(&vxlan->age_timer, next_timer);
}

static void vxlan_vs_del_dev(struct vxlan_dev *vxlan)
{
        struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);

        spin_lock(&vn->sock_lock);
        hlist_del_init_rcu(&vxlan->hlist4.hlist);
#if IS_ENABLED(CONFIG_IPV6)
        hlist_del_init_rcu(&vxlan->hlist6.hlist);
#endif
        spin_unlock(&vn->sock_lock);
}

static void vxlan_vs_add_dev(struct vxlan_sock *vs, struct vxlan_dev *vxlan,
                             struct vxlan_dev_node *node)
{
        struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);
        __be32 vni = vxlan->default_dst.remote_vni;

        node->vxlan = vxlan;
        spin_lock(&vn->sock_lock);
        hlist_add_head_rcu(&node->hlist, vni_head(vs, vni));
        spin_unlock(&vn->sock_lock);
}

/* Setup stats when device is created */
static int vxlan_init(struct net_device *dev)
{
        dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
        if (!dev->tstats)
                return -ENOMEM;

        return 0;
}

static void vxlan_fdb_delete_default(struct vxlan_dev *vxlan, __be32 vni)
{
        struct vxlan_fdb *f;

        spin_lock_bh(&vxlan->hash_lock);
        f = __vxlan_find_mac(vxlan, all_zeros_mac, vni);
        if (f)
                vxlan_fdb_destroy(vxlan, f);
        spin_unlock_bh(&vxlan->hash_lock);
}

static void vxlan_uninit(struct net_device *dev)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);

        gro_cells_destroy(&vxlan->gro_cells);

        vxlan_fdb_delete_default(vxlan, vxlan->cfg.vni);

        free_percpu(dev->tstats);
}

/* Start ageing timer and join group when device is brought up */
static int vxlan_open(struct net_device *dev)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        int ret;

        ret = vxlan_sock_add(vxlan);
        if (ret < 0)
                return ret;

        if (vxlan_addr_multicast(&vxlan->default_dst.remote_ip)) {
                ret = vxlan_igmp_join(vxlan);
                if (ret == -EADDRINUSE)
                        ret = 0;
                if (ret) {
                        vxlan_sock_release(vxlan);
                        return ret;
                }
        }

        if (vxlan->cfg.age_interval)
                mod_timer(&vxlan->age_timer, jiffies + FDB_AGE_INTERVAL);

        return ret;
}

/* Purge the forwarding table */
static void vxlan_flush(struct vxlan_dev *vxlan, bool do_all)
{
        unsigned int h;

        spin_lock_bh(&vxlan->hash_lock);
        for (h = 0; h < FDB_HASH_SIZE; ++h) {
                struct hlist_node *p, *n;
                hlist_for_each_safe(p, n, &vxlan->fdb_head[h]) {
                        struct vxlan_fdb *f
                                = container_of(p, struct vxlan_fdb, hlist);
                        if (!do_all && (f->state & (NUD_PERMANENT | NUD_NOARP)))
                                continue;
                        /* the all_zeros_mac entry is deleted at vxlan_uninit */
                        if (!is_zero_ether_addr(f->eth_addr))
                                vxlan_fdb_destroy(vxlan, f);
                }
        }
        spin_unlock_bh(&vxlan->hash_lock);
}

/* Cleanup timer and forwarding table on shutdown */
static int vxlan_stop(struct net_device *dev)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);
        int ret = 0;

        if (vxlan_addr_multicast(&vxlan->default_dst.remote_ip) &&
            !vxlan_group_used(vn, vxlan))
                ret = vxlan_igmp_leave(vxlan);

        del_timer_sync(&vxlan->age_timer);

        vxlan_flush(vxlan, false);
        vxlan_sock_release(vxlan);

        return ret;
}

/* Stub, nothing needs to be done. */
static void vxlan_set_multicast_list(struct net_device *dev)
{
}

static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_rdst *dst = &vxlan->default_dst;
        struct net_device *lowerdev = __dev_get_by_index(vxlan->net,
                                                         dst->remote_ifindex);
        bool use_ipv6 = !!(vxlan->cfg.flags & VXLAN_F_IPV6);

        /* This check is different than dev->max_mtu, because it looks at
         * the lowerdev->mtu, rather than the static dev->max_mtu
         */
        if (lowerdev) {
                int max_mtu = lowerdev->mtu -
                              (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM);
                if (new_mtu > max_mtu)
                        return -EINVAL;
        }

        dev->mtu = new_mtu;
        return 0;
}

static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct ip_tunnel_info *info = skb_tunnel_info(skb);
        __be16 sport, dport;

        sport = udp_flow_src_port(dev_net(dev), skb, vxlan->cfg.port_min,
                                  vxlan->cfg.port_max, true);
        dport = info->key.tp_dst ? : vxlan->cfg.dst_port;

        if (ip_tunnel_info_af(info) == AF_INET) {
                struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock);
                struct rtable *rt;

                rt = vxlan_get_route(vxlan, dev, sock4, skb, 0, info->key.tos,
                                     info->key.u.ipv4.dst,
                                     &info->key.u.ipv4.src, dport, sport,
                                     &info->dst_cache, info);
                if (IS_ERR(rt))
                        return PTR_ERR(rt);
                ip_rt_put(rt);
        } else {
#if IS_ENABLED(CONFIG_IPV6)
                struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock);
                struct dst_entry *ndst;

                ndst = vxlan6_get_route(vxlan, dev, sock6, skb, 0, info->key.tos,
                                        info->key.label, &info->key.u.ipv6.dst,
                                        &info->key.u.ipv6.src, dport, sport,
                                        &info->dst_cache, info);
                if (IS_ERR(ndst))
                        return PTR_ERR(ndst);
                dst_release(ndst);
#else /* !CONFIG_IPV6 */
                return -EPFNOSUPPORT;
#endif
        }
        info->key.tp_src = sport;
        info->key.tp_dst = dport;
        return 0;
}

static const struct net_device_ops vxlan_netdev_ether_ops = {
        .ndo_size               = sizeof(struct net_device_ops),
        .ndo_init               = vxlan_init,
        .ndo_uninit             = vxlan_uninit,
        .ndo_open               = vxlan_open,
        .ndo_stop               = vxlan_stop,
        .ndo_start_xmit         = vxlan_xmit,
        .ndo_get_stats64        = ip_tunnel_get_stats64,
        .ndo_set_rx_mode        = vxlan_set_multicast_list,
        .extended.ndo_change_mtu        = vxlan_change_mtu,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_fdb_add            = vxlan_fdb_add,
        .ndo_fdb_del            = vxlan_fdb_delete,
        .extended.ndo_fdb_dump  = vxlan_fdb_dump,
        .ndo_fill_metadata_dst  = vxlan_fill_metadata_dst,
};

static const struct net_device_ops vxlan_netdev_raw_ops = {
        .ndo_size               = sizeof(struct net_device_ops),
        .ndo_init               = vxlan_init,
        .ndo_uninit             = vxlan_uninit,
        .ndo_open               = vxlan_open,
        .ndo_stop               = vxlan_stop,
        .ndo_start_xmit         = vxlan_xmit,
        .ndo_get_stats64        = ip_tunnel_get_stats64,
        .extended.ndo_change_mtu        = vxlan_change_mtu,
        .ndo_fill_metadata_dst  = vxlan_fill_metadata_dst,
};

/* Info for udev, that this is a virtual tunnel endpoint */
static struct device_type vxlan_type = {
        .name = "vxlan",
};

/* Calls the ndo_udp_tunnel_add of the caller in order to
 * supply the listening VXLAN udp ports. Callers are expected
 * to implement the ndo_udp_tunnel_add.
 */
static void vxlan_offload_rx_ports(struct net_device *dev, bool push)
{
        struct vxlan_sock *vs;
        struct net *net = dev_net(dev);
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        unsigned int i;

        spin_lock(&vn->sock_lock);
        for (i = 0; i < PORT_HASH_SIZE; ++i) {
                hlist_for_each_entry_rcu(vs, &vn->sock_list[i], hlist) {
                        unsigned short type;

                        if (vs->flags & VXLAN_F_GPE)
                                type = UDP_TUNNEL_TYPE_VXLAN_GPE;
                        else
                                type = UDP_TUNNEL_TYPE_VXLAN;

                        if (push)
                                udp_tunnel_push_rx_port(dev, vs->sock, type);
                        else
                                udp_tunnel_drop_rx_port(dev, vs->sock, type);
                }
        }
        spin_unlock(&vn->sock_lock);
}

/* Initialize the device structure. */
static void vxlan_setup(struct net_device *dev)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        unsigned int h;

        eth_hw_addr_random(dev);
        ether_setup(dev);

        dev->extended->needs_free_netdev = true;
        SET_NETDEV_DEVTYPE(dev, &vxlan_type);

        dev->features   |= NETIF_F_LLTX;
        dev->features   |= NETIF_F_SG | NETIF_F_HW_CSUM;
        dev->features   |= NETIF_F_RXCSUM;
        dev->features   |= NETIF_F_GSO_SOFTWARE;

        dev->vlan_features = dev->features;
        dev->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_RXCSUM;
        dev->hw_features |= NETIF_F_GSO_SOFTWARE;
        netif_keep_dst(dev);
        dev->priv_flags |= IFF_NO_QUEUE;

        /* MTU range: 68 - 65535 */
        dev->extended->min_mtu = ETH_MIN_MTU;
        dev->extended->max_mtu = ETH_MAX_MTU;

        INIT_LIST_HEAD(&vxlan->next);
        spin_lock_init(&vxlan->hash_lock);

        init_timer_deferrable(&vxlan->age_timer);
        vxlan->age_timer.function = vxlan_cleanup;
        vxlan->age_timer.data = (unsigned long) vxlan;

        vxlan->dev = dev;

        gro_cells_init(&vxlan->gro_cells, dev);

        for (h = 0; h < FDB_HASH_SIZE; ++h)
                INIT_HLIST_HEAD(&vxlan->fdb_head[h]);
}

static void vxlan_ether_setup(struct net_device *dev)
{
        dev->priv_flags &= ~IFF_TX_SKB_SHARING;
        dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
        dev->netdev_ops = &vxlan_netdev_ether_ops;
}

static void vxlan_raw_setup(struct net_device *dev)
{
        dev->header_ops = NULL;
        dev->type = ARPHRD_NONE;
        dev->hard_header_len = 0;
        dev->addr_len = 0;
        dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
        dev->netdev_ops = &vxlan_netdev_raw_ops;
}

static const struct nla_policy vxlan_policy[IFLA_VXLAN_MAX + 1] = {
        [IFLA_VXLAN_ID]         = { .type = NLA_U32 },
        [IFLA_VXLAN_GROUP]      = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
        [IFLA_VXLAN_GROUP6]     = { .len = sizeof(struct in6_addr) },
        [IFLA_VXLAN_LINK]       = { .type = NLA_U32 },
        [IFLA_VXLAN_LOCAL]      = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
        [IFLA_VXLAN_LOCAL6]     = { .len = sizeof(struct in6_addr) },
        [IFLA_VXLAN_TOS]        = { .type = NLA_U8 },
        [IFLA_VXLAN_TTL]        = { .type = NLA_U8 },
        [IFLA_VXLAN_LABEL]      = { .type = NLA_U32 },
        [IFLA_VXLAN_LEARNING]   = { .type = NLA_U8 },
        [IFLA_VXLAN_AGEING]     = { .type = NLA_U32 },
        [IFLA_VXLAN_LIMIT]      = { .type = NLA_U32 },
        [IFLA_VXLAN_PORT_RANGE] = { .len  = sizeof(struct ifla_vxlan_port_range) },
        [IFLA_VXLAN_PROXY]      = { .type = NLA_U8 },
        [IFLA_VXLAN_RSC]        = { .type = NLA_U8 },
        [IFLA_VXLAN_L2MISS]     = { .type = NLA_U8 },
        [IFLA_VXLAN_L3MISS]     = { .type = NLA_U8 },
        [IFLA_VXLAN_COLLECT_METADATA]   = { .type = NLA_U8 },
        [IFLA_VXLAN_PORT]       = { .type = NLA_U16 },
        [IFLA_VXLAN_UDP_CSUM]   = { .type = NLA_U8 },
        [IFLA_VXLAN_UDP_ZERO_CSUM6_TX]  = { .type = NLA_U8 },
        [IFLA_VXLAN_UDP_ZERO_CSUM6_RX]  = { .type = NLA_U8 },
        [IFLA_VXLAN_REMCSUM_TX] = { .type = NLA_U8 },
        [IFLA_VXLAN_REMCSUM_RX] = { .type = NLA_U8 },
        [IFLA_VXLAN_GBP]        = { .type = NLA_FLAG, },
        [IFLA_VXLAN_GPE]        = { .type = NLA_FLAG, },
        [IFLA_VXLAN_REMCSUM_NOPARTIAL]  = { .type = NLA_FLAG },
        [IFLA_VXLAN_TTL_INHERIT]        = { .type = NLA_FLAG },
};

static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[])
{
        if (tb[IFLA_ADDRESS]) {
                if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) {
                        pr_debug("invalid link address (not ethernet)\n");
                        return -EINVAL;
                }

                if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) {
                        pr_debug("invalid all zero ethernet address\n");
                        return -EADDRNOTAVAIL;
                }
        }

        if (tb[IFLA_MTU]) {
                u32 mtu = nla_get_u32(tb[IFLA_MTU]);

                if (mtu < ETH_MIN_MTU || mtu > ETH_MAX_MTU)
                        return -EINVAL;
        }

        if (!data)
                return -EINVAL;

        if (data[IFLA_VXLAN_ID]) {
                u32 id = nla_get_u32(data[IFLA_VXLAN_ID]);

                if (id >= VXLAN_N_VID)
                        return -ERANGE;
        }

        if (data[IFLA_VXLAN_PORT_RANGE]) {
                const struct ifla_vxlan_port_range *p
                        = nla_data(data[IFLA_VXLAN_PORT_RANGE]);

                if (ntohs(p->high) < ntohs(p->low)) {
                        pr_debug("port range %u .. %u not valid\n",
                                 ntohs(p->low), ntohs(p->high));
                        return -EINVAL;
                }
        }

        return 0;
}

static void vxlan_get_drvinfo(struct net_device *netdev,
                              struct ethtool_drvinfo *drvinfo)
{
        strlcpy(drvinfo->version, VXLAN_VERSION, sizeof(drvinfo->version));
        strlcpy(drvinfo->driver, "vxlan", sizeof(drvinfo->driver));
}

static const struct ethtool_ops vxlan_ethtool_ops = {
        .get_drvinfo    = vxlan_get_drvinfo,
        .get_link       = ethtool_op_get_link,
};

static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
                                        __be16 port, u32 flags)
{
        struct socket *sock;
        struct udp_port_cfg udp_conf;
        int err;

        memset(&udp_conf, 0, sizeof(udp_conf));

        if (ipv6) {
                udp_conf.family = AF_INET6;
                udp_conf.use_udp6_rx_checksums =
                    !(flags & VXLAN_F_UDP_ZERO_CSUM6_RX);
                udp_conf.ipv6_v6only = 1;
        } else {
                udp_conf.family = AF_INET;
        }

        udp_conf.local_udp_port = port;

        /* Open UDP socket */
        err = udp_sock_create(net, &udp_conf, &sock);
        if (err < 0)
                return ERR_PTR(err);

        return sock;
}

/* Create new listen socket if needed */
static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
                                              __be16 port, u32 flags)
{
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        struct vxlan_sock *vs;
        struct socket *sock;
        unsigned int h;
        struct udp_tunnel_sock_cfg tunnel_cfg;

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

        for (h = 0; h < VNI_HASH_SIZE; ++h)
                INIT_HLIST_HEAD(&vs->vni_list[h]);

        sock = vxlan_create_sock(net, ipv6, port, flags);
        if (IS_ERR(sock)) {
                kfree(vs);
                return ERR_CAST(sock);
        }

        vs->sock = sock;
        atomic_set(&vs->refcnt, 1);
        vs->flags = (flags & VXLAN_F_RCV_FLAGS);

        spin_lock(&vn->sock_lock);
        hlist_add_head_rcu(&vs->hlist, vs_head(net, port));
        udp_tunnel_notify_add_rx_port(sock,
                                      (vs->flags & VXLAN_F_GPE) ?
                                      UDP_TUNNEL_TYPE_VXLAN_GPE :
                                      UDP_TUNNEL_TYPE_VXLAN);
        spin_unlock(&vn->sock_lock);

        /* Mark socket as an encapsulation socket. */
        memset(&tunnel_cfg, 0, sizeof(tunnel_cfg));
        tunnel_cfg.sk_user_data = vs;
        tunnel_cfg.encap_type = 1;
        tunnel_cfg.encap_rcv = vxlan_rcv;
        tunnel_cfg.encap_err_lookup = vxlan_err_lookup;
        tunnel_cfg.encap_destroy = NULL;
        tunnel_cfg.gro_receive = vxlan_gro_receive;
        tunnel_cfg.gro_complete = vxlan_gro_complete;

        setup_udp_tunnel_sock(net, sock, &tunnel_cfg);

        return vs;
}

static int __vxlan_sock_add(struct vxlan_dev *vxlan, bool ipv6)
{
        struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);
        struct vxlan_sock *vs = NULL;
        struct vxlan_dev_node *node;

        if (!vxlan->cfg.no_share) {
                spin_lock(&vn->sock_lock);
                vs = vxlan_find_sock(vxlan->net, ipv6 ? AF_INET6 : AF_INET,
                                     vxlan->cfg.dst_port, vxlan->cfg.flags);
                if (vs && !atomic_add_unless(&vs->refcnt, 1, 0)) {
                        spin_unlock(&vn->sock_lock);
                        return -EBUSY;
                }
                spin_unlock(&vn->sock_lock);
        }
        if (!vs)
                vs = vxlan_socket_create(vxlan->net, ipv6,
                                         vxlan->cfg.dst_port, vxlan->cfg.flags);
        if (IS_ERR(vs))
                return PTR_ERR(vs);
#if IS_ENABLED(CONFIG_IPV6)
        if (ipv6) {
                rcu_assign_pointer(vxlan->vn6_sock, vs);
                node = &vxlan->hlist6;
        } else
#endif
        {
                rcu_assign_pointer(vxlan->vn4_sock, vs);
                node = &vxlan->hlist4;
        }
        vxlan_vs_add_dev(vs, vxlan, node);
        return 0;
}

static int vxlan_sock_add(struct vxlan_dev *vxlan)
{
        bool metadata = vxlan->cfg.flags & VXLAN_F_COLLECT_METADATA;
        bool ipv6 = vxlan->cfg.flags & VXLAN_F_IPV6 || metadata;
        bool ipv4 = !ipv6 || metadata;
        int ret = 0;

        RCU_INIT_POINTER(vxlan->vn4_sock, NULL);
#if IS_ENABLED(CONFIG_IPV6)
        RCU_INIT_POINTER(vxlan->vn6_sock, NULL);
        if (ipv6) {
                ret = __vxlan_sock_add(vxlan, true);
                if (ret < 0 && ret != -EAFNOSUPPORT)
                        ipv4 = false;
        }
#endif
        if (ipv4)
                ret = __vxlan_sock_add(vxlan, false);
        if (ret < 0)
                vxlan_sock_release(vxlan);
        return ret;
}

static int vxlan_config_validate(struct net *src_net, struct vxlan_config *conf,
                                 struct net_device **lower,
                                 struct vxlan_dev *old)
{
        struct vxlan_net *vn = net_generic(src_net, vxlan_net_id);
        struct vxlan_dev *tmp;
        bool use_ipv6 = false;

        if (conf->flags & VXLAN_F_GPE) {
                /* For now, allow GPE only together with
                 * COLLECT_METADATA. This can be relaxed later; in such
                 * case, the other side of the PtP link will have to be
                 * provided.
                 */
                if ((conf->flags & ~VXLAN_F_ALLOWED_GPE) ||
                    !(conf->flags & VXLAN_F_COLLECT_METADATA)) {
                        return -EINVAL;
                }
        }

        if (!conf->remote_ip.sa.sa_family && !conf->saddr.sa.sa_family) {
                /* Unless IPv6 is explicitly requested, assume IPv4 */
                conf->remote_ip.sa.sa_family = AF_INET;
                conf->saddr.sa.sa_family = AF_INET;
        } else if (!conf->remote_ip.sa.sa_family) {
                conf->remote_ip.sa.sa_family = conf->saddr.sa.sa_family;
        } else if (!conf->saddr.sa.sa_family) {
                conf->saddr.sa.sa_family = conf->remote_ip.sa.sa_family;
        }

        if (conf->saddr.sa.sa_family != conf->remote_ip.sa.sa_family)
                return -EINVAL;

        if (vxlan_addr_multicast(&conf->saddr))
                return -EINVAL;

        if (conf->saddr.sa.sa_family == AF_INET6) {
                if (!IS_ENABLED(CONFIG_IPV6))
                        return -EPFNOSUPPORT;
                use_ipv6 = true;
                conf->flags |= VXLAN_F_IPV6;

                if (!(conf->flags & VXLAN_F_COLLECT_METADATA)) {
                        int local_type =
                                ipv6_addr_type(&conf->saddr.sin6.sin6_addr);
                        int remote_type =
                                ipv6_addr_type(&conf->remote_ip.sin6.sin6_addr);

                        if (local_type & IPV6_ADDR_LINKLOCAL) {
                                if (!(remote_type & IPV6_ADDR_LINKLOCAL) &&
                                    (remote_type != IPV6_ADDR_ANY))
                                        return -EINVAL;

                                conf->flags |= VXLAN_F_IPV6_LINKLOCAL;
                        } else {
                                if (remote_type ==
                                    (IPV6_ADDR_UNICAST | IPV6_ADDR_LINKLOCAL))
                                        return -EINVAL;

                                conf->flags &= ~VXLAN_F_IPV6_LINKLOCAL;
                        }
                }
        }

        if (conf->label && !use_ipv6)
                return -EINVAL;

        if (conf->remote_ifindex) {
                struct net_device *lowerdev;

                lowerdev = __dev_get_by_index(src_net, conf->remote_ifindex);
                if (!lowerdev)
                        return -ENODEV;

#if IS_ENABLED(CONFIG_IPV6)
                if (use_ipv6) {
                        struct inet6_dev *idev = __in6_dev_get(lowerdev);
                        if (idev && idev->cnf.disable_ipv6)
                                return -EPERM;
                }
#endif

                *lower = lowerdev;
        } else {
                if (vxlan_addr_multicast(&conf->remote_ip))
                        return -EINVAL;

#if IS_ENABLED(CONFIG_IPV6)
                if (conf->flags & VXLAN_F_IPV6_LINKLOCAL)
                        return -EINVAL;
#endif