/*
 * 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/types.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/rculist.h>
#include <linux/netdevice.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/igmp.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/hash.h>
#include <linux/ethtool.h>
#include <net/arp.h>
#include <net/ndisc.h>
#include <net/ip.h>
#include <net/ip_tunnels.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/rtnetlink.h>
#include <net/route.h>
#include <net/dsfield.h>
#include <net/inet_ecn.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/vxlan.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/addrconf.h>
#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 VNI_HASH_BITS   10
#define VNI_HASH_SIZE   (1<<VNI_HASH_BITS)
#define FDB_HASH_BITS   8
#define FDB_HASH_SIZE   (1<<FDB_HASH_BITS)
#define FDB_AGE_DEFAULT 300 /* 5 min */
#define FDB_AGE_INTERVAL (10 * HZ)      /* rescan interval */

#define VXLAN_N_VID     (1u << 24)
#define VXLAN_VID_MASK  (VXLAN_N_VID - 1)
/* IP header + UDP + VXLAN + Ethernet header */
#define VXLAN_HEADROOM (20 + 8 + 8 + 14)
/* IPv6 header + UDP + VXLAN + Ethernet header */
#define VXLAN6_HEADROOM (40 + 8 + 8 + 14)
#define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))

#define VXLAN_FLAGS 0x08000000  /* struct vxlanhdr.vx_flags required value. */

/* VXLAN protocol header */
struct vxlanhdr {
        __be32 vx_flags;
        __be32 vx_vni;
};

/* 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 const u8 all_zeros_mac[ETH_ALEN];

/* 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;
};

union vxlan_addr {
        struct sockaddr_in sin;
        struct sockaddr_in6 sin6;
        struct sockaddr sa;
};

struct vxlan_rdst {
        union vxlan_addr         remote_ip;
        __be16                   remote_port;
        u32                      remote_vni;
        u32                      remote_ifindex;
        struct list_head         list;
        struct rcu_head          rcu;
};

/* 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;
        u16               state;        /* see ndm_state */
        u8                flags;        /* see ndm_flags */
        u8                eth_addr[ETH_ALEN];
};

/* Pseudo network device */
struct vxlan_dev {
        struct hlist_node hlist;        /* vni hash table */
        struct list_head  next;         /* vxlan's per namespace list */
        struct vxlan_sock *vn_sock;     /* listening socket */
        struct net_device *dev;
        struct vxlan_rdst default_dst;  /* default destination */
        union vxlan_addr  saddr;        /* source address */
        __be16            dst_port;
        __u16             port_min;     /* source port range */
        __u16             port_max;
        __u8              tos;          /* TOS override */
        __u8              ttl;
        u32               flags;        /* VXLAN_F_* below */

        struct work_struct sock_work;
        struct work_struct igmp_join;
        struct work_struct igmp_leave;

        unsigned long     age_interval;
        struct timer_list age_timer;
        spinlock_t        hash_lock;
        unsigned int      addrcnt;
        unsigned int      addrmax;

        struct hlist_head fdb_head[FDB_HASH_SIZE];
};

#define VXLAN_F_LEARN   0x01
#define VXLAN_F_PROXY   0x02
#define VXLAN_F_RSC     0x04
#define VXLAN_F_L2MISS  0x08
#define VXLAN_F_L3MISS  0x10
#define VXLAN_F_IPV6    0x20 /* internal flag */

/* salt for hash table */
static u32 vxlan_salt __read_mostly;
static struct workqueue_struct *vxlan_wq;

static void vxlan_sock_work(struct work_struct *work);

#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 inline bool vxlan_addr_any(const union vxlan_addr *ipa)
{
       if (ipa->sa.sa_family == AF_INET6)
               return ipv6_addr_any(&ipa->sin6.sin6_addr);
       else
               return ipa->sin.sin_addr.s_addr == htonl(INADDR_ANY);
}

static inline bool vxlan_addr_multicast(const union vxlan_addr *ipa)
{
       if (ipa->sa.sa_family == AF_INET6)
               return ipv6_addr_is_multicast(&ipa->sin6.sin6_addr);
       else
               return IN_MULTICAST(ntohl(ipa->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)) {
               nla_memcpy(&ip->sin6.sin6_addr, nla, sizeof(struct in6_addr));
               ip->sa.sa_family = AF_INET6;
               return 0;
       } else if (nla_len(nla) >= sizeof(__be32)) {
               ip->sin.sin_addr.s_addr = nla_get_be32(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(skb, attr, sizeof(struct in6_addr), &ip->sin6.sin6_addr);
       else
               return nla_put_be32(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 inline bool vxlan_addr_any(const union vxlan_addr *ipa)
{
       return ipa->sin.sin_addr.s_addr == htonl(INADDR_ANY);
}

static inline bool vxlan_addr_multicast(const union vxlan_addr *ipa)
{
       return IN_MULTICAST(ntohl(ipa->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_be32(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_be32(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, u32 id)
{
        return &vs->vni_list[hash_32(id, 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 and UDP port */
static struct vxlan_sock *vxlan_find_sock(struct net *net, __be16 port)
{
        struct vxlan_sock *vs;

        hlist_for_each_entry_rcu(vs, vs_head(net, port), hlist) {
                if (inet_sk(vs->sock->sk)->inet_sport == port)
                        return vs;
        }
        return NULL;
}

static struct vxlan_dev *vxlan_vs_find_vni(struct vxlan_sock *vs, u32 id)
{
        struct vxlan_dev *vxlan;

        hlist_for_each_entry_rcu(vxlan, vni_head(vs, id), hlist) {
                if (vxlan->default_dst.remote_vni == id)
                        return vxlan;
        }

        return NULL;
}

/* Look up VNI in a per net namespace table */
static struct vxlan_dev *vxlan_find_vni(struct net *net, u32 id, __be16 port)
{
        struct vxlan_sock *vs;

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

        return vxlan_vs_find_vni(vs, id);
}

/* 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) {
                ndm->ndm_family = AF_INET;
                send_ip = !vxlan_addr_any(&rdst->remote_ip);
                send_eth = !is_zero_ether_addr(fdb->eth_addr);
        } else
                ndm->ndm_family = AF_BRIDGE;
        ndm->ndm_state = fdb->state;
        ndm->ndm_ifindex = vxlan->dev->ifindex;
        ndm->ndm_flags = fdb->flags;
        ndm->ndm_type = NDA_DST;

        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->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, rdst->remote_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;

        return nlmsg_end(skb, nlh);

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(struct nda_cacheinfo));
}

static void vxlan_fdb_notify(struct vxlan_dev *vxlan,
                             struct vxlan_fdb *fdb, 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,
                             first_remote_rtnl(fdb));
        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 = VXLAN_N_VID,
        };

        INIT_LIST_HEAD(&f.remotes);
        list_add_rcu(&remote.list, &f.remotes);

        vxlan_fdb_notify(vxlan, &f, RTM_GETNEIGH);
}

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

        INIT_LIST_HEAD(&f.remotes);
        memcpy(f.eth_addr, eth_addr, ETH_ALEN);

        vxlan_fdb_notify(vxlan, &f, 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);
}

/* Hash chain to use given mac address */
static inline struct hlist_head *vxlan_fdb_head(struct vxlan_dev *vxlan,
                                                const u8 *mac)
{
        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)

{
        struct hlist_head *head = vxlan_fdb_head(vxlan, mac);
        struct vxlan_fdb *f;

        hlist_for_each_entry_rcu(f, head, hlist) {
                if (ether_addr_equal(mac, f->eth_addr))
                        return f;
        }

        return NULL;
}

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

        f = __vxlan_find_mac(vxlan, mac);
        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,
                                              __u32 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, __u32 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;
        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, __u32 vni, __u32 ifindex)
{
        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;
        rd->remote_ip = *ip;
        rd->remote_port = port;
        rd->remote_vni = vni;
        rd->remote_ifindex = ifindex;

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

        return 1;
}

/* Notify netdevs that UDP port started listening */
static void vxlan_notify_add_rx_port(struct sock *sk)
{
        struct net_device *dev;
        struct net *net = sock_net(sk);
        sa_family_t sa_family = sk->sk_family;
        __be16 port = inet_sk(sk)->inet_sport;

        rcu_read_lock();
        for_each_netdev_rcu(net, dev) {
                if (dev->netdev_ops->ndo_add_vxlan_port)
                        dev->netdev_ops->ndo_add_vxlan_port(dev, sa_family,
                                                            port);
        }
        rcu_read_unlock();
}

/* Notify netdevs that UDP port is no more listening */
static void vxlan_notify_del_rx_port(struct sock *sk)
{
        struct net_device *dev;
        struct net *net = sock_net(sk);
        sa_family_t sa_family = sk->sk_family;
        __be16 port = inet_sk(sk)->inet_sport;

        rcu_read_lock();
        for_each_netdev_rcu(net, dev) {
                if (dev->netdev_ops->ndo_del_vxlan_port)
                        dev->netdev_ops->ndo_del_vxlan_port(dev, sa_family,
                                                            port);
        }
        rcu_read_unlock();
}

/* 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, __u32 vni, __u32 ifindex,
                            __u8 ndm_flags)
{
        struct vxlan_fdb *f;
        int notify = 0;

        f = __vxlan_find_mac(vxlan, mac);
        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))) {
                                int rc = vxlan_fdb_replace(f, ip, port, vni,
                                                           ifindex);

                                if (rc < 0)
                                        return rc;
                                notify |= rc;
                        } else
                                return -EOPNOTSUPP;
                }
                if ((flags & NLM_F_APPEND) &&
                    (is_multicast_ether_addr(f->eth_addr) ||
                     is_zero_ether_addr(f->eth_addr))) {
                        int rc = vxlan_fdb_append(f, ip, port, vni, ifindex);

                        if (rc < 0)
                                return rc;
                        notify |= rc;
                }
        } else {
                if (!(flags & NLM_F_CREATE))
                        return -ENOENT;

                if (vxlan->addrmax && vxlan->addrcnt >= vxlan->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;
                INIT_LIST_HEAD(&f->remotes);
                memcpy(f->eth_addr, mac, ETH_ALEN);

                vxlan_fdb_append(f, ip, port, vni, ifindex);

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

        if (notify)
                vxlan_fdb_notify(vxlan, f, 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)
                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, RTM_DELNEIGH);

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

static int vxlan_fdb_parse(struct nlattr *tb[], struct vxlan_dev *vxlan,
                           union vxlan_addr *ip, __be16 *port, u32 *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->dst_port;
        }

        if (tb[NDA_VNI]) {
                if (nla_len(tb[NDA_VNI]) != sizeof(u32))
                        return -EINVAL;
                *vni = nla_get_u32(tb[NDA_VNI]);
        } else {
                *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;
                dev_put(tdev);
        } 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 flags)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        /* struct net *net = dev_net(vxlan->dev); */
        union vxlan_addr ip;
        __be16 port;
        u32 vni, 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, &vni, &ifindex);
        if (err)
                return err;

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

        return err;
}

/* Delete entry (via netlink) */
static int vxlan_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
                            struct net_device *dev,
                            const unsigned char *addr)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_fdb *f;
        struct vxlan_rdst *rd = NULL;
        union vxlan_addr ip;
        __be16 port;
        u32 vni, ifindex;
        int err;

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

        err = -ENOENT;

        spin_lock_bh(&vxlan->hash_lock);
        f = vxlan_find_mac(vxlan, addr);
        if (!f)
                goto out;

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

        err = 0;

        /* 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)) {
                list_del_rcu(&rd->list);
                kfree_rcu(rd, rcu);
                goto out;
        }

        vxlan_fdb_destroy(vxlan, f);

out:
        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, int idx)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        unsigned int h;

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

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

                        if (idx < cb->args[0])
                                goto skip;

                        list_for_each_entry_rcu(rd, &f->remotes, list) {
                                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;
                }
        }
out:
        return idx;
}

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

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

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

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

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

                rdst->remote_ip = *src_ip;
                f->updated = jiffies;
                vxlan_fdb_notify(vxlan, f, 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->dst_port,
                                         vxlan->default_dst.remote_vni,
                                         0, 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, union vxlan_addr *remote_ip)
{
        struct vxlan_dev *vxlan;

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

                if (vxlan_addr_equal(&vxlan->default_dst.remote_ip,
                                     remote_ip))
                        return true;
        }

        return false;
}

static void vxlan_sock_hold(struct vxlan_sock *vs)
{
        atomic_inc(&vs->refcnt);
}

void vxlan_sock_release(struct vxlan_sock *vs)
{
        struct sock *sk = vs->sock->sk;
        struct net *net = sock_net(sk);
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);

        if (!atomic_dec_and_test(&vs->refcnt))
                return;

        spin_lock(&vn->sock_lock);
        hlist_del_rcu(&vs->hlist);
        rcu_assign_sk_user_data(vs->sock->sk, NULL);
        vxlan_notify_del_rx_port(sk);
        spin_unlock(&vn->sock_lock);

        queue_work(vxlan_wq, &vs->del_work);
}
EXPORT_SYMBOL_GPL(vxlan_sock_release);

/* Callback to update multicast group membership when first VNI on
 * multicast asddress is brought up
 * Done as workqueue because ip_mc_join_group acquires RTNL.
 */
static void vxlan_igmp_join(struct work_struct *work)
{
        struct vxlan_dev *vxlan = container_of(work, struct vxlan_dev, igmp_join);
        struct vxlan_sock *vs = vxlan->vn_sock;
        struct sock *sk = vs->sock->sk;
        union vxlan_addr *ip = &vxlan->default_dst.remote_ip;
        int ifindex = vxlan->default_dst.remote_ifindex;

        lock_sock(sk);
        if (ip->sa.sa_family == AF_INET) {
                struct ip_mreqn mreq = {
                        .imr_multiaddr.s_addr   = ip->sin.sin_addr.s_addr,
                        .imr_ifindex            = ifindex,
                };

                ip_mc_join_group(sk, &mreq);
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                ipv6_stub->ipv6_sock_mc_join(sk, ifindex,
                                             &ip->sin6.sin6_addr);
#endif
        }
        release_sock(sk);

        vxlan_sock_release(vs);
        dev_put(vxlan->dev);
}

/* Inverse of vxlan_igmp_join when last VNI is brought down */
static void vxlan_igmp_leave(struct work_struct *work)
{
        struct vxlan_dev *vxlan = container_of(work, struct vxlan_dev, igmp_leave);
        struct vxlan_sock *vs = vxlan->vn_sock;
        struct sock *sk = vs->sock->sk;

        union vxlan_addr *ip = &vxlan->default_dst.remote_ip;
        int ifindex = vxlan->default_dst.remote_ifindex;

        lock_sock(sk);
        if (ip->sa.sa_family == AF_INET) {
                struct ip_mreqn mreq = {
                        .imr_multiaddr.s_addr   = ip->sin.sin_addr.s_addr,
                        .imr_ifindex            = ifindex,
                };

                ip_mc_leave_group(sk, &mreq);
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                ipv6_stub->ipv6_sock_mc_drop(sk, ifindex,
                                             &ip->sin6.sin6_addr);
#endif
        }

        release_sock(sk);

        vxlan_sock_release(vs);
        dev_put(vxlan->dev);
}

/* Callback from net/ipv4/udp.c to receive packets */
static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
{
        struct vxlan_sock *vs;
        struct vxlanhdr *vxh;
        __be16 port;

        /* Need Vxlan and inner Ethernet header to be present */
        if (!pskb_may_pull(skb, VXLAN_HLEN))
                goto error;

        /* Return packets with reserved bits set */
        vxh = (struct vxlanhdr *)(udp_hdr(skb) + 1);
        if (vxh->vx_flags != htonl(VXLAN_FLAGS) ||
            (vxh->vx_vni & htonl(0xff))) {
                netdev_dbg(skb->dev, "invalid vxlan flags=%#x vni=%#x\n",
                           ntohl(vxh->vx_flags), ntohl(vxh->vx_vni));
                goto error;
        }

        if (iptunnel_pull_header(skb, VXLAN_HLEN, htons(ETH_P_TEB)))
                goto drop;

        port = inet_sk(sk)->inet_sport;

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

        vs->rcv(vs, skb, vxh->vx_vni);
        return 0;

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

error:
        /* Return non vxlan pkt */
        return 1;
}

static void vxlan_rcv(struct vxlan_sock *vs,
                      struct sk_buff *skb, __be32 vx_vni)
{
        struct iphdr *oip = NULL;
        struct ipv6hdr *oip6 = NULL;
        struct vxlan_dev *vxlan;
        struct pcpu_tstats *stats;
        union vxlan_addr saddr;
        __u32 vni;
        int err = 0;
        union vxlan_addr *remote_ip;

        vni = ntohl(vx_vni) >> 8;
        /* Is this VNI defined? */
        vxlan = vxlan_vs_find_vni(vs, vni);
        if (!vxlan)
                goto drop;

        remote_ip = &vxlan->default_dst.remote_ip;
        skb_reset_mac_header(skb);
        skb->protocol = eth_type_trans(skb, vxlan->dev);

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

        /* Re-examine inner Ethernet packet */
        if (remote_ip->sa.sa_family == AF_INET) {
                oip = ip_hdr(skb);
                saddr.sin.sin_addr.s_addr = oip->saddr;
                saddr.sa.sa_family = AF_INET;
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                oip6 = ipv6_hdr(skb);
                saddr.sin6.sin6_addr = oip6->saddr;
                saddr.sa.sa_family = AF_INET6;
#endif
        }

        if ((vxlan->flags & VXLAN_F_LEARN) &&
            vxlan_snoop(skb->dev, &saddr, eth_hdr(skb)->h_source))
                goto drop;

        skb_reset_network_header(skb);

        /* If the NIC driver gave us an encapsulated packet with
         * CHECKSUM_UNNECESSARY and Rx checksum feature is enabled,
         * leave the CHECKSUM_UNNECESSARY, the device checksummed it
         * for us. Otherwise force the upper layers to verify it.
         */
        if (skb->ip_summed != CHECKSUM_UNNECESSARY || !skb->encapsulation ||
            !(vxlan->dev->features & NETIF_F_RXCSUM))
                skb->ip_summed = CHECKSUM_NONE;

        skb->encapsulation = 0;

        if (oip6)
                err = IP6_ECN_decapsulate(oip6, skb);
        if (oip)
                err = IP_ECN_decapsulate(oip, skb);

        if (unlikely(err)) {
                if (log_ecn_error) {
                        if (oip6)
                                net_info_ratelimited("non-ECT from %pI6\n",
                                                     &oip6->saddr);
                        if (oip)
                                net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
                                                     &oip->saddr, oip->tos);
                }
                if (err > 1) {
                        ++vxlan->dev->stats.rx_frame_errors;
                        ++vxlan->dev->stats.rx_errors;
                        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);

        netif_rx(skb);

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

static int arp_reduce(struct net_device *dev, struct sk_buff *skb)
{
        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);
                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);

                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->flags & VXLAN_F_L3MISS) {
                union vxlan_addr ipa = {
                        .sin.sin_addr.s_addr = tip,
                        .sa.sa_family = AF_INET,
                };

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

#if IS_ENABLED(CONFIG_IPV6)
static int neigh_reduce(struct net_device *dev, struct sk_buff *skb)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct neighbour *n;
        union vxlan_addr ipa;
        const struct ipv6hdr *iphdr;
        const struct in6_addr *saddr, *daddr;
        struct nd_msg *msg;
        struct inet6_dev *in6_dev = NULL;

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

        if (!pskb_may_pull(skb, skb->len))
                goto out;

        iphdr = ipv6_hdr(skb);
        saddr = &iphdr->saddr;
        daddr = &iphdr->daddr;

        if (ipv6_addr_loopback(daddr) ||
            ipv6_addr_is_multicast(daddr))
                goto out;

        msg = (struct nd_msg *)skb_transport_header(skb);
        if (msg->icmph.icmp6_code != 0 ||
            msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
                goto out;

        n = neigh_lookup(ipv6_stub->nd_tbl, daddr, dev);

        if (n) {
                struct vxlan_fdb *f;

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

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

                ipv6_stub->ndisc_send_na(dev, n, saddr, &msg->target,
                                         !!in6_dev->cnf.forwarding,
                                         true, false, false);
                neigh_release(n);
        } else if (vxlan->flags & VXLAN_F_L3MISS) {
                ipa.sin6.sin6_addr = *daddr;
                ipa.sa.sa_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->flags & VXLAN_F_L3MISS)) {
                        union vxlan_addr ipa = {
                                .sin.sin_addr.s_addr = pip->daddr,
                                .sa.sa_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->flags & VXLAN_F_L3MISS)) {
                        union vxlan_addr ipa = {
                                .sin6.sin6_addr = pip6->daddr,
                                .sa.sa_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_sock_put(struct sk_buff *skb)
{
        sock_put(skb->sk);
}

/* On transmit, associate with the tunnel socket */
static void vxlan_set_owner(struct sock *sk, struct sk_buff *skb)
{
        skb_orphan(skb);
        sock_hold(sk);
        skb->sk = sk;
        skb->destructor = vxlan_sock_put;
}

/* Compute source port for outgoing packet
 *   first choice to use L4 flow hash since it will spread
 *     better and maybe available from hardware
 *   secondary choice is to use jhash on the Ethernet header
 */
__be16 vxlan_src_port(__u16 port_min, __u16 port_max, struct sk_buff *skb)
{
        unsigned int range = (port_max - port_min) + 1;
        u32 hash;

        hash = skb_get_rxhash(skb);
        if (!hash)
                hash = jhash(skb->data, 2 * ETH_ALEN,
                             (__force u32) skb->protocol);

        return htons((((u64) hash * range) >> 32) + port_min);
}
EXPORT_SYMBOL_GPL(vxlan_src_port);

static int handle_offloads(struct sk_buff *skb)
{
        if (skb_is_gso(skb)) {
                int err = skb_unclone(skb, GFP_ATOMIC);
                if (unlikely(err))
                        return err;

                skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
        } else if (skb->ip_summed != CHECKSUM_PARTIAL)
                skb->ip_summed = CHECKSUM_NONE;

        return 0;
}

#if IS_ENABLED(CONFIG_IPV6)
static int vxlan6_xmit_skb(struct vxlan_sock *vs,
                           struct dst_entry *dst, struct sk_buff *skb,
                           struct net_device *dev, struct in6_addr *saddr,
                           struct in6_addr *daddr, __u8 prio, __u8 ttl,
                           __be16 src_port, __be16 dst_port, __be32 vni)
{
        struct ipv6hdr *ip6h;
        struct vxlanhdr *vxh;
        struct udphdr *uh;
        int min_headroom;
        int err;

        if (!skb->encapsulation) {
                skb_reset_inner_headers(skb);
                skb->encapsulation = 1;
        }

        skb_scrub_packet(skb, false);

        min_headroom = LL_RESERVED_SPACE(dst->dev) + dst->header_len
                        + VXLAN_HLEN + sizeof(struct ipv6hdr)
                        + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);

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

        if (vlan_tx_tag_present(skb)) {
                if (WARN_ON(!__vlan_put_tag(skb,
                                            skb->vlan_proto,
                                            vlan_tx_tag_get(skb))))
                        return -ENOMEM;

                skb->vlan_tci = 0;
        }

        vxh = (struct vxlanhdr *) __skb_push(skb, sizeof(*vxh));
        vxh->vx_flags = htonl(VXLAN_FLAGS);
        vxh->vx_vni = vni;

        __skb_push(skb, sizeof(*uh));
        skb_reset_transport_header(skb);
        uh = udp_hdr(skb);

        uh->dest = dst_port;
        uh->source = src_port;

        uh->len = htons(skb->len);
        uh->check = 0;

        memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
        IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
                              IPSKB_REROUTED);
        skb_dst_set(skb, dst);

        if (!skb_is_gso(skb) && !(dst->dev->features & NETIF_F_IPV6_CSUM)) {
                __wsum csum = skb_checksum(skb, 0, skb->len, 0);
                skb->ip_summed = CHECKSUM_UNNECESSARY;
                uh->check = csum_ipv6_magic(saddr, daddr, skb->len,
                                            IPPROTO_UDP, csum);
                if (uh->check == 0)
                        uh->check = CSUM_MANGLED_0;
        } else {
                skb->ip_summed = CHECKSUM_PARTIAL;
                skb->csum_start = skb_transport_header(skb) - skb->head;
                skb->csum_offset = offsetof(struct udphdr, check);
                uh->check = ~csum_ipv6_magic(saddr, daddr,
                                             skb->len, IPPROTO_UDP, 0);
        }

        __skb_push(skb, sizeof(*ip6h));
        skb_reset_network_header(skb);
        ip6h              = ipv6_hdr(skb);
        ip6h->version     = 6;
        ip6h->priority    = prio;
        ip6h->flow_lbl[0] = 0;
        ip6h->flow_lbl[1] = 0;
        ip6h->flow_lbl[2] = 0;
        ip6h->payload_len = htons(skb->len);
        ip6h->nexthdr     = IPPROTO_UDP;
        ip6h->hop_limit   = ttl;
        ip6h->daddr       = *daddr;
        ip6h->saddr       = *saddr;

        vxlan_set_owner(vs->sock->sk, skb);

        err = handle_offloads(skb);
        if (err)
                return err;

        ip6tunnel_xmit(skb, dev);
        return 0;
}
#endif

int vxlan_xmit_skb(struct vxlan_sock *vs,
                   struct rtable *rt, struct sk_buff *skb,
                   __be32 src, __be32 dst, __u8 tos, __u8 ttl, __be16 df,
                   __be16 src_port, __be16 dst_port, __be32 vni)
{
        struct vxlanhdr *vxh;
        struct udphdr *uh;
        int min_headroom;
        int err;

        if (!skb->encapsulation) {
                skb_reset_inner_headers(skb);
                skb->encapsulation = 1;
        }

        min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
                        + VXLAN_HLEN + sizeof(struct iphdr)
                        + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);

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

        if (vlan_tx_tag_present(skb)) {
                if (WARN_ON(!__vlan_put_tag(skb,
                                            skb->vlan_proto,
                                            vlan_tx_tag_get(skb))))
                        return -ENOMEM;

                skb->vlan_tci = 0;
        }

        vxh = (struct vxlanhdr *) __skb_push(skb, sizeof(*vxh));
        vxh->vx_flags = htonl(VXLAN_FLAGS);
        vxh->vx_vni = vni;

        __skb_push(skb, sizeof(*uh));
        skb_reset_transport_header(skb);
        uh = udp_hdr(skb);

        uh->dest = dst_port;
        uh->source = src_port;

        uh->len = htons(skb->len);
        uh->check = 0;

        vxlan_set_owner(vs->sock->sk, skb);

        err = handle_offloads(skb);
        if (err)
                return err;

        return iptunnel_xmit(rt, skb, src, dst, IPPROTO_UDP, tos, ttl, df,
                             false);
}
EXPORT_SYMBOL_GPL(vxlan_xmit_skb);

/* 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)
{
        struct pcpu_tstats *tx_stats = this_cpu_ptr(src_vxlan->dev->tstats);
        struct pcpu_tstats *rx_stats = this_cpu_ptr(dst_vxlan->dev->tstats);
        union vxlan_addr loopback;
        union vxlan_addr *remote_ip = &dst_vxlan->default_dst.remote_ip;

        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
        }

        if (dst_vxlan->flags & VXLAN_F_LEARN)
                vxlan_snoop(skb->dev, &loopback, eth_hdr(skb)->h_source);

        u64_stats_update_begin(&tx_stats->syncp);
        tx_stats->tx_packets++;
        tx_stats->tx_bytes += skb->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 += skb->len;
                u64_stats_update_end(&rx_stats->syncp);
        } else {
                skb->dev->stats.rx_dropped++;
        }
}

static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                           struct vxlan_rdst *rdst, bool did_rsc)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct rtable *rt = NULL;
        const struct iphdr *old_iph;
        struct flowi4 fl4;
        union vxlan_addr *dst;
        __be16 src_port = 0, dst_port;
        u32 vni;
        __be16 df = 0;
        __u8 tos, ttl;
        int err;

        dst_port = rdst->remote_port ? rdst->remote_port : vxlan->dst_port;
        vni = rdst->remote_vni;
        dst = &rdst->remote_ip;

        if (vxlan_addr_any(dst)) {
                if (did_rsc) {
                        /* short-circuited back to local bridge */
                        vxlan_encap_bypass(skb, vxlan, vxlan);
                        return;
                }
                goto drop;
        }

        old_iph = ip_hdr(skb);

        ttl = vxlan->ttl;
        if (!ttl && vxlan_addr_multicast(dst))
                ttl = 1;

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

        src_port = vxlan_src_port(vxlan->port_min, vxlan->port_max, skb);

        if (dst->sa.sa_family == AF_INET) {
                memset(&fl4, 0, sizeof(fl4));
                fl4.flowi4_oif = rdst->remote_ifindex;
                fl4.flowi4_tos = RT_TOS(tos);
                fl4.daddr = dst->sin.sin_addr.s_addr;
                fl4.saddr = vxlan->saddr.sin.sin_addr.s_addr;

                rt = ip_route_output_key(dev_net(dev), &fl4);
                if (IS_ERR(rt)) {
                        netdev_dbg(dev, "no route to %pI4\n",
                                   &dst->sin.sin_addr.s_addr);
                        dev->stats.tx_carrier_errors++;
                        goto tx_error;
                }

                if (rt->dst.dev == dev) {
                        netdev_dbg(dev, "circular route to %pI4\n",
                                   &dst->sin.sin_addr.s_addr);
                        dev->stats.collisions++;
                        goto tx_error;
                }

                /* Bypass encapsulation if the destination is local */
                if (rt->rt_flags & RTCF_LOCAL &&
                    !(rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))) {
                        struct vxlan_dev *dst_vxlan;

                        ip_rt_put(rt);
                        dst_vxlan = vxlan_find_vni(dev_net(dev), vni, dst_port);
                        if (!dst_vxlan)
                                goto tx_error;
                        vxlan_encap_bypass(skb, vxlan, dst_vxlan);
                        return;
                }

                tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
                ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);

                err = vxlan_xmit_skb(vxlan->vn_sock, rt, skb,
                                     fl4.saddr, dst->sin.sin_addr.s_addr,
                                     tos, ttl, df, src_port, dst_port,
                                     htonl(vni << 8));

                if (err < 0)
                        goto rt_tx_error;
                iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
#if IS_ENABLED(CONFIG_IPV6)
        } else {
                struct sock *sk = vxlan->vn_sock->sock->sk;
                struct dst_entry *ndst;
                struct flowi6 fl6;
                u32 flags;

                memset(&fl6, 0, sizeof(fl6));
                fl6.flowi6_oif = rdst->remote_ifindex;
                fl6.daddr = dst->sin6.sin6_addr;
                fl6.saddr = vxlan->saddr.sin6.sin6_addr;
                fl6.flowi6_proto = IPPROTO_UDP;

                if (ipv6_stub->ipv6_dst_lookup(sk, &ndst, &fl6)) {
                        netdev_dbg(dev, "no route to %pI6\n",
                                   &dst->sin6.sin6_addr);
                        dev->stats.tx_carrier_errors++;
                        goto tx_error;
                }

                if (ndst->dev == dev) {
                        netdev_dbg(dev, "circular route to %pI6\n",
                                   &dst->sin6.sin6_addr);
                        dst_release(ndst);
                        dev->stats.collisions++;
                        goto tx_error;
                }

                /* Bypass encapsulation if the destination is local */
                flags = ((struct rt6_info *)ndst)->rt6i_flags;
                if (flags & RTF_LOCAL &&
                    !(flags & (RTCF_BROADCAST | RTCF_MULTICAST))) {
                        struct vxlan_dev *dst_vxlan;

                        dst_release(ndst);
                        dst_vxlan = vxlan_find_vni(dev_net(dev), vni, dst_port);
                        if (!dst_vxlan)
                                goto tx_error;
                        vxlan_encap_bypass(skb, vxlan, dst_vxlan);
                        return;
                }

                ttl = ttl ? : ip6_dst_hoplimit(ndst);

                err = vxlan6_xmit_skb(vxlan->vn_sock, ndst, skb,
                                      dev, &fl6.saddr, &fl6.daddr, 0, ttl,
                                      src_port, dst_port, htonl(vni << 8));
#endif
        }

        return;

drop:
        dev->stats.tx_dropped++;
        goto tx_free;

rt_tx_error:
        ip_rt_put(rt);
tx_error:
        dev->stats.tx_errors++;
tx_free:
        dev_kfree_skb(skb);
}

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

        skb_reset_mac_header(skb);
        eth = eth_hdr(skb);

        if ((vxlan->flags & VXLAN_F_PROXY)) {
                if (ntohs(eth->h_proto) == ETH_P_ARP)
                        return arp_reduce(dev, skb);
#if IS_ENABLED(CONFIG_IPV6)
                else if (ntohs(eth->h_proto) == ETH_P_IPV6 &&
                         skb->len >= sizeof(struct ipv6hdr) + sizeof(struct nd_msg) &&
                         ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
                                struct nd_msg *msg;

                                msg = (struct nd_msg *)skb_transport_header(skb);
                                if (msg->icmph.icmp6_code == 0 &&
                                    msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION)
                                        return neigh_reduce(dev, skb);
                }
#endif
        }

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

        if (f && (f->flags & NTF_ROUTER) && (vxlan->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);
        }

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

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

        list_for_each_entry_rcu(rdst, &f->remotes, list) {
                struct sk_buff *skb1;

                skb1 = skb_clone(skb, GFP_ATOMIC);
                if (skb1)
                        vxlan_xmit_one(skb1, dev, rdst, did_rsc);
        }

        dev_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;

        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);
                        unsigned long timeout;

                        if (f->state & NUD_PERMANENT)
                                continue;

                        timeout = f->used + vxlan->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_add_dev(struct vxlan_sock *vs, struct vxlan_dev *vxlan)
{
        __u32 vni = vxlan->default_dst.remote_vni;

        vxlan->vn_sock = vs;
        hlist_add_head_rcu(&vxlan->hlist, vni_head(vs, vni));
}

/* Setup stats when device is created */
static int vxlan_init(struct net_device *dev)
{
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_net *vn = net_generic(dev_net(dev), vxlan_net_id);
        struct vxlan_sock *vs;

        dev->tstats = alloc_percpu(struct pcpu_tstats);
        if (!dev->tstats)
                return -ENOMEM;

        spin_lock(&vn->sock_lock);
        vs = vxlan_find_sock(dev_net(dev), vxlan->dst_port);
        if (vs) {
                /* If we have a socket with same port already, reuse it */
                atomic_inc(&vs->refcnt);
                vxlan_vs_add_dev(vs, vxlan);
        } else {
                /* otherwise make new socket outside of RTNL */
                dev_hold(dev);
                queue_work(vxlan_wq, &vxlan->sock_work);
        }
        spin_unlock(&vn->sock_lock);

        return 0;
}

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

        spin_lock_bh(&vxlan->hash_lock);
        f = __vxlan_find_mac(vxlan, all_zeros_mac);
        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);
        struct vxlan_sock *vs = vxlan->vn_sock;

        vxlan_fdb_delete_default(vxlan);

        if (vs)
                vxlan_sock_release(vs);
        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_net *vn = net_generic(dev_net(dev), vxlan_net_id);
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_sock *vs = vxlan->vn_sock;

        /* socket hasn't been created */
        if (!vs)
                return -ENOTCONN;

        if (vxlan_addr_multicast(&vxlan->default_dst.remote_ip) &&
            vxlan_group_used(vn, &vxlan->default_dst.remote_ip)) {
                vxlan_sock_hold(vs);
                dev_hold(dev);
                queue_work(vxlan_wq, &vxlan->igmp_join);
        }

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

        return 0;
}

/* Purge the forwarding table */
static void vxlan_flush(struct vxlan_dev *vxlan)
{
        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);
                        /* 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_net *vn = net_generic(dev_net(dev), vxlan_net_id);
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_sock *vs = vxlan->vn_sock;

        if (vs && vxlan_addr_multicast(&vxlan->default_dst.remote_ip) &&
            ! vxlan_group_used(vn, &vxlan->default_dst.remote_ip)) {
                vxlan_sock_hold(vs);
                dev_hold(dev);
                queue_work(vxlan_wq, &vxlan->igmp_leave);
        }

        del_timer_sync(&vxlan->age_timer);

        vxlan_flush(vxlan);

        return 0;
}

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

static const struct net_device_ops vxlan_netdev_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,
        .ndo_change_mtu         = eth_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,
        .ndo_fdb_dump           = vxlan_fdb_dump,
};

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

/* Calls the ndo_add_vxlan_port of the caller in order to
 * supply the listening VXLAN udp ports. Callers are expected
 * to implement the ndo_add_vxlan_port.
 */
void vxlan_get_rx_port(struct net_device *dev)
{
        struct vxlan_sock *vs;
        struct net *net = dev_net(dev);
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        sa_family_t sa_family;
        __be16 port;
        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) {
                        port = inet_sk(vs->sock->sk)->inet_sport;
                        sa_family = vs->sock->sk->sk_family;
                        dev->netdev_ops->ndo_add_vxlan_port(dev, sa_family,
                                                            port);
                }
        }
        spin_unlock(&vn->sock_lock);
}
EXPORT_SYMBOL_GPL(vxlan_get_rx_port);

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

        eth_hw_addr_random(dev);
        ether_setup(dev);
        if (vxlan->default_dst.remote_ip.sa.sa_family == AF_INET6)
                dev->hard_header_len = ETH_HLEN + VXLAN6_HEADROOM;
        else
                dev->hard_header_len = ETH_HLEN + VXLAN_HEADROOM;

        dev->netdev_ops = &vxlan_netdev_ops;
        dev->destructor = free_netdev;
        SET_NETDEV_DEVTYPE(dev, &vxlan_type);

        dev->tx_queue_len = 0;
        dev->features   |= NETIF_F_LLTX;
        dev->features   |= NETIF_F_NETNS_LOCAL;
        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->features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
        dev->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_RXCSUM;
        dev->hw_features |= NETIF_F_GSO_SOFTWARE;
        dev->hw_features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
        dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
        dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;

        INIT_LIST_HEAD(&vxlan->next);
        spin_lock_init(&vxlan->hash_lock);
        INIT_WORK(&vxlan->igmp_join, vxlan_igmp_join);
        INIT_WORK(&vxlan->igmp_leave, vxlan_igmp_leave);
        INIT_WORK(&vxlan->sock_work, vxlan_sock_work);

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

        inet_get_local_port_range(&low, &high);
        vxlan->port_min = low;
        vxlan->port_max = high;
        vxlan->dst_port = htons(vxlan_port);

        vxlan->dev = dev;

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

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_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_PORT]       = { .type = NLA_U16 },
};

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 (!data)
                return -EINVAL;

        if (data[IFLA_VXLAN_ID]) {
                __u32 id = nla_get_u32(data[IFLA_VXLAN_ID]);
                if (id >= VXLAN_VID_MASK)
                        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 void vxlan_del_work(struct work_struct *work)
{
        struct vxlan_sock *vs = container_of(work, struct vxlan_sock, del_work);

        sk_release_kernel(vs->sock->sk);
        kfree_rcu(vs, rcu);
}

#if IS_ENABLED(CONFIG_IPV6)
/* Create UDP socket for encapsulation receive. AF_INET6 socket
 * could be used for both IPv4 and IPv6 communications, but
 * users may set bindv6only=1.
 */
static int create_v6_sock(struct net *net, __be16 port, struct socket **psock)
{
        struct sock *sk;
        struct socket *sock;
        struct sockaddr_in6 vxlan_addr = {
                .sin6_family = AF_INET6,
                .sin6_port = port,
        };
        int rc, val = 1;

        rc = sock_create_kern(AF_INET6, SOCK_DGRAM, IPPROTO_UDP, &sock);
        if (rc < 0) {
                pr_debug("UDPv6 socket create failed\n");
                return rc;
        }

        /* Put in proper namespace */
        sk = sock->sk;
        sk_change_net(sk, net);

        kernel_setsockopt(sock, SOL_IPV6, IPV6_V6ONLY,
                          (char *)&val, sizeof(val));
        rc = kernel_bind(sock, (struct sockaddr *)&vxlan_addr,
                         sizeof(struct sockaddr_in6));
        if (rc < 0) {
                pr_debug("bind for UDPv6 socket %pI6:%u (%d)\n",
                         &vxlan_addr.sin6_addr, ntohs(vxlan_addr.sin6_port), rc);
                sk_release_kernel(sk);
                return rc;
        }
        /* At this point, IPv6 module should have been loaded in
         * sock_create_kern().
         */
        BUG_ON(!ipv6_stub);

        *psock = sock;
        /* Disable multicast loopback */
        inet_sk(sk)->mc_loop = 0;
        return 0;
}

#else

static int create_v6_sock(struct net *net, __be16 port, struct socket **psock)
{
                return -EPFNOSUPPORT;
}
#endif

static int create_v4_sock(struct net *net, __be16 port, struct socket **psock)
{
        struct sock *sk;
        struct socket *sock;
        struct sockaddr_in vxlan_addr = {
                .sin_family = AF_INET,
                .sin_addr.s_addr = htonl(INADDR_ANY),
                .sin_port = port,
        };
        int rc;

        /* Create UDP socket for encapsulation receive. */
        rc = sock_create_kern(AF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
        if (rc < 0) {
                pr_debug("UDP socket create failed\n");
                return rc;
        }

        /* Put in proper namespace */
        sk = sock->sk;
        sk_change_net(sk, net);

        rc = kernel_bind(sock, (struct sockaddr *) &vxlan_addr,
                         sizeof(vxlan_addr));
        if (rc < 0) {
                pr_debug("bind for UDP socket %pI4:%u (%d)\n",
                         &vxlan_addr.sin_addr, ntohs(vxlan_addr.sin_port), rc);
                sk_release_kernel(sk);
                return rc;
        }

        *psock = sock;
        /* Disable multicast loopback */
        inet_sk(sk)->mc_loop = 0;
        return 0;
}

/* Create new listen socket if needed */
static struct vxlan_sock *vxlan_socket_create(struct net *net, __be16 port,
                                              vxlan_rcv_t *rcv, void *data, bool ipv6)
{
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        struct vxlan_sock *vs;
        struct socket *sock;
        struct sock *sk;
        int rc = 0;
        unsigned int h;

        vs = kmalloc(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]);

        INIT_WORK(&vs->del_work, vxlan_del_work);

        if (ipv6)
                rc = create_v6_sock(net, port, &sock);
        else
                rc = create_v4_sock(net, port, &sock);
        if (rc < 0) {
                kfree(vs);
                return ERR_PTR(rc);
        }

        vs->sock = sock;
        sk = sock->sk;
        atomic_set(&vs->refcnt, 1);
        vs->rcv = rcv;
        vs->data = data;
        rcu_assign_sk_user_data(vs->sock->sk, vs);

        spin_lock(&vn->sock_lock);
        hlist_add_head_rcu(&vs->hlist, vs_head(net, port));
        vxlan_notify_add_rx_port(sk);
        spin_unlock(&vn->sock_lock);

        /* Mark socket as an encapsulation socket. */
        udp_sk(sk)->encap_type = 1;
        udp_sk(sk)->encap_rcv = vxlan_udp_encap_recv;
#if IS_ENABLED(CONFIG_IPV6)
        if (ipv6)
                ipv6_stub->udpv6_encap_enable();
        else
#endif
                udp_encap_enable();

        return vs;
}

struct vxlan_sock *vxlan_sock_add(struct net *net, __be16 port,
                                  vxlan_rcv_t *rcv, void *data,
                                  bool no_share, bool ipv6)
{
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        struct vxlan_sock *vs;

        vs = vxlan_socket_create(net, port, rcv, data, ipv6);
        if (!IS_ERR(vs))
                return vs;

        if (no_share)   /* Return error if sharing is not allowed. */
                return vs;

        spin_lock(&vn->sock_lock);
        vs = vxlan_find_sock(net, port);
        if (vs) {
                if (vs->rcv == rcv)
                        atomic_inc(&vs->refcnt);
                else
                        vs = ERR_PTR(-EBUSY);
        }
        spin_unlock(&vn->sock_lock);

        if (!vs)
                vs = ERR_PTR(-EINVAL);

        return vs;
}
EXPORT_SYMBOL_GPL(vxlan_sock_add);

/* Scheduled at device creation to bind to a socket */
static void vxlan_sock_work(struct work_struct *work)
{
        struct vxlan_dev *vxlan = container_of(work, struct vxlan_dev, sock_work);
        struct net *net = dev_net(vxlan->dev);
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        __be16 port = vxlan->dst_port;
        struct vxlan_sock *nvs;

        nvs = vxlan_sock_add(net, port, vxlan_rcv, NULL, false, vxlan->flags & VXLAN_F_IPV6);
        spin_lock(&vn->sock_lock);
        if (!IS_ERR(nvs))
                vxlan_vs_add_dev(nvs, vxlan);
        spin_unlock(&vn->sock_lock);

        dev_put(vxlan->dev);
}

static int vxlan_newlink(struct net *net, struct net_device *dev,
                         struct nlattr *tb[], struct nlattr *data[])
{
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        struct vxlan_dev *vxlan = netdev_priv(dev);
        struct vxlan_rdst *dst = &vxlan->default_dst;
        __u32 vni;
        int err;
        bool use_ipv6 = false;

        if (!data[IFLA_VXLAN_ID])
                return -EINVAL;

        vni = nla_get_u32(data[IFLA_VXLAN_ID]);
        dst->remote_vni = vni;

        if (data[IFLA_VXLAN_GROUP]) {
                dst->remote_ip.sin.sin_addr.s_addr = nla_get_be32(data[IFLA_VXLAN_GROUP]);
                dst->remote_ip.sa.sa_family = AF_INET;
        } else if (data[IFLA_VXLAN_GROUP6]) {
                if (!IS_ENABLED(CONFIG_IPV6))
                        return -EPFNOSUPPORT;

                nla_memcpy(&dst->remote_ip.sin6.sin6_addr, data[IFLA_VXLAN_GROUP6],
                           sizeof(struct in6_addr));
                dst->remote_ip.sa.sa_family = AF_INET6;
                use_ipv6 = true;
        }

        if (data[IFLA_VXLAN_LOCAL]) {
                vxlan->saddr.sin.sin_addr.s_addr = nla_get_be32(data[IFLA_VXLAN_LOCAL]);
                vxlan->saddr.sa.sa_family = AF_INET;
        } else if (data[IFLA_VXLAN_LOCAL6]) {
                if (!IS_ENABLED(CONFIG_IPV6))
                        return -EPFNOSUPPORT;

                /* TODO: respect scope id */
                nla_memcpy(&vxlan->saddr.sin6.sin6_addr, data[IFLA_VXLAN_LOCAL6],
                           sizeof(struct in6_addr));
                vxlan->saddr.sa.sa_family = AF_INET6;
                use_ipv6 = true;
        }

        if (data[IFLA_VXLAN_LINK] &&
            (dst->remote_ifindex = nla_get_u32(data[IFLA_VXLAN_LINK]))) {
                struct net_device *lowerdev
                         = __dev_get_by_index(net, dst->remote_ifindex);

                if (!lowerdev) {
                        pr_info("ifindex %d does not exist\n", dst->remote_ifindex);
                        return -ENODEV;
                }

#if IS_ENABLED(CONFIG_IPV6)
                if (use_ipv6) {
                        struct inet6_dev *idev = __in6_dev_get(lowerdev);
                        if (idev && idev->cnf.disable_ipv6) {
                                pr_info("IPv6 is disabled via sysctl\n");
                                return -EPERM;
                        }
                        vxlan->flags |= VXLAN_F_IPV6;
                }
#endif

                if (!tb[IFLA_MTU])
                        dev->mtu = lowerdev->mtu - (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM);

                /* update header length based on lower device */
                dev->hard_header_len = lowerdev->hard_header_len +
                                       (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM);
        }

        if (data[IFLA_VXLAN_TOS])
                vxlan->tos  = nla_get_u8(data[IFLA_VXLAN_TOS]);

        if (data[IFLA_VXLAN_TTL])
                vxlan->ttl = nla_get_u8(data[IFLA_VXLAN_TTL]);

        if (!data[IFLA_VXLAN_LEARNING] || nla_get_u8(data[IFLA_VXLAN_LEARNING]))
                vxlan->flags |= VXLAN_F_LEARN;

        if (data[IFLA_VXLAN_AGEING])
                vxlan->age_interval = nla_get_u32(data[IFLA_VXLAN_AGEING]);
        else
                vxlan->age_interval = FDB_AGE_DEFAULT;

        if (data[IFLA_VXLAN_PROXY] && nla_get_u8(data[IFLA_VXLAN_PROXY]))
                vxlan->flags |= VXLAN_F_PROXY;

        if (data[IFLA_VXLAN_RSC] && nla_get_u8(data[IFLA_VXLAN_RSC]))
                vxlan->flags |= VXLAN_F_RSC;

        if (data[IFLA_VXLAN_L2MISS] && nla_get_u8(data[IFLA_VXLAN_L2MISS]))
                vxlan->flags |= VXLAN_F_L2MISS;

        if (data[IFLA_VXLAN_L3MISS] && nla_get_u8(data[IFLA_VXLAN_L3MISS]))
                vxlan->flags |= VXLAN_F_L3MISS;

        if (data[IFLA_VXLAN_LIMIT])
                vxlan->addrmax = nla_get_u32(data[IFLA_VXLAN_LIMIT]);

        if (data[IFLA_VXLAN_PORT_RANGE]) {
                const struct ifla_vxlan_port_range *p
                        = nla_data(data[IFLA_VXLAN_PORT_RANGE]);
                vxlan->port_min = ntohs(p->low);
                vxlan->port_max = ntohs(p->high);
        }

        if (data[IFLA_VXLAN_PORT])
                vxlan->dst_port = nla_get_be16(data[IFLA_VXLAN_PORT]);

        if (vxlan_find_vni(net, vni, vxlan->dst_port)) {
                pr_info("duplicate VNI %u\n", vni);
                return -EEXIST;
        }

        SET_ETHTOOL_OPS(dev, &vxlan_ethtool_ops);

        /* create an fdb entry for a valid default destination */
        if (!vxlan_addr_any(&vxlan->default_dst.remote_ip)) {
                err = vxlan_fdb_create(vxlan, all_zeros_mac,
                                       &vxlan->default_dst.remote_ip,
                                       NUD_REACHABLE|NUD_PERMANENT,
                                       NLM_F_EXCL|NLM_F_CREATE,
                                       vxlan->dst_port,
                                       vxlan->default_dst.remote_vni,
                                       vxlan->default_dst.remote_ifindex,
                                       NTF_SELF);
                if (err)
                        return err;
        }

        err = register_netdevice(dev);
        if (err) {
                vxlan_fdb_delete_default(vxlan);
                return err;
        }

        list_add(&vxlan->next, &vn->vxlan_list);

        return 0;
}

static void vxlan_dellink(struct net_device *dev, struct list_head *head)
{
        struct vxlan_net *vn = net_generic(dev_net(dev), vxlan_net_id);
        struct vxlan_dev *vxlan = netdev_priv(dev);

        spin_lock(&vn->sock_lock);
        if (!hlist_unhashed(&vxlan->hlist))
                hlist_del_rcu(&vxlan->hlist);
        spin_unlock(&vn->sock_lock);

        list_del(&vxlan->next);
        unregister_netdevice_queue(dev, head);
}

static size_t vxlan_get_size(const struct net_device *dev)
{

        return nla_total_size(sizeof(__u32)) +  /* IFLA_VXLAN_ID */
                nla_total_size(sizeof(struct in6_addr)) + /* IFLA_VXLAN_GROUP{6} */
                nla_total_size(sizeof(__u32)) + /* IFLA_VXLAN_LINK */
                nla_total_size(sizeof(struct in6_addr)) + /* IFLA_VXLAN_LOCAL{6} */
                nla_total_size(sizeof(__u8)) +  /* IFLA_VXLAN_TTL */
                nla_total_size(sizeof(__u8)) +  /* IFLA_VXLAN_TOS */
                nla_total_size(sizeof(__u8)) +  /* IFLA_VXLAN_LEARNING */
                nla_total_size(sizeof(__u8)) +  /* IFLA_VXLAN_PROXY */
                nla_total_size(sizeof(__u8)) +  /* IFLA_VXLAN_RSC */
                nla_total_size(sizeof(__u8)) +  /* IFLA_VXLAN_L2MISS */
                nla_total_size(sizeof(__u8)) +  /* IFLA_VXLAN_L3MISS */
                nla_total_size(sizeof(__u32)) + /* IFLA_VXLAN_AGEING */
                nla_total_size(sizeof(__u32)) + /* IFLA_VXLAN_LIMIT */
                nla_total_size(sizeof(struct ifla_vxlan_port_range)) +
                nla_total_size(sizeof(__be16))+ /* IFLA_VXLAN_PORT */
                0;
}

static int vxlan_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
        const struct vxlan_dev *vxlan = netdev_priv(dev);
        const struct vxlan_rdst *dst = &vxlan->default_dst;
        struct ifla_vxlan_port_range ports = {
                .low =  htons(vxlan->port_min),
                .high = htons(vxlan->port_max),
        };

        if (nla_put_u32(skb, IFLA_VXLAN_ID, dst->remote_vni))
                goto nla_put_failure;

        if (!vxlan_addr_any(&dst->remote_ip)) {
                if (dst->remote_ip.sa.sa_family == AF_INET) {
                        if (nla_put_be32(skb, IFLA_VXLAN_GROUP,
                                         dst->remote_ip.sin.sin_addr.s_addr))
                                goto nla_put_failure;
#if IS_ENABLED(CONFIG_IPV6)
                } else {
                        if (nla_put(skb, IFLA_VXLAN_GROUP6, sizeof(struct in6_addr),
                                    &dst->remote_ip.sin6.sin6_addr))
                                goto nla_put_failure;
#endif
                }
        }

        if (dst->remote_ifindex && nla_put_u32(skb, IFLA_VXLAN_LINK, dst->remote_ifindex))
                goto nla_put_failure;

        if (!vxlan_addr_any(&vxlan->saddr)) {
                if (vxlan->saddr.sa.sa_family == AF_INET) {
                        if (nla_put_be32(skb, IFLA_VXLAN_LOCAL,
                                         vxlan->saddr.sin.sin_addr.s_addr))
                                goto nla_put_failure;
#if IS_ENABLED(CONFIG_IPV6)
                } else {
                        if (nla_put(skb, IFLA_VXLAN_LOCAL6, sizeof(struct in6_addr),
                                    &vxlan->saddr.sin6.sin6_addr))
                                goto nla_put_failure;
#endif
                }
        }

        if (nla_put_u8(skb, IFLA_VXLAN_TTL, vxlan->ttl) ||
            nla_put_u8(skb, IFLA_VXLAN_TOS, vxlan->tos) ||
            nla_put_u8(skb, IFLA_VXLAN_LEARNING,
                        !!(vxlan->flags & VXLAN_F_LEARN)) ||
            nla_put_u8(skb, IFLA_VXLAN_PROXY,
                        !!(vxlan->flags & VXLAN_F_PROXY)) ||
            nla_put_u8(skb, IFLA_VXLAN_RSC, !!(vxlan->flags & VXLAN_F_RSC)) ||
            nla_put_u8(skb, IFLA_VXLAN_L2MISS,
                        !!(vxlan->flags & VXLAN_F_L2MISS)) ||
            nla_put_u8(skb, IFLA_VXLAN_L3MISS,
                        !!(vxlan->flags & VXLAN_F_L3MISS)) ||
            nla_put_u32(skb, IFLA_VXLAN_AGEING, vxlan->age_interval) ||
            nla_put_u32(skb, IFLA_VXLAN_LIMIT, vxlan->addrmax) ||
            nla_put_be16(skb, IFLA_VXLAN_PORT, vxlan->dst_port))
                goto nla_put_failure;

        if (nla_put(skb, IFLA_VXLAN_PORT_RANGE, sizeof(ports), &ports))
                goto nla_put_failure;

        return 0;

nla_put_failure:
        return -EMSGSIZE;
}

static struct rtnl_link_ops vxlan_link_ops __read_mostly = {
        .kind           = "vxlan",
        .maxtype        = IFLA_VXLAN_MAX,
        .policy         = vxlan_policy,
        .priv_size      = sizeof(struct vxlan_dev),
        .setup          = vxlan_setup,
        .validate       = vxlan_validate,
        .newlink        = vxlan_newlink,
        .dellink        = vxlan_dellink,
        .get_size       = vxlan_get_size,
        .fill_info      = vxlan_fill_info,
};

static __net_init int vxlan_init_net(struct net *net)
{
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        unsigned int h;

        INIT_LIST_HEAD(&vn->vxlan_list);
        spin_lock_init(&vn->sock_lock);

        for (h = 0; h < PORT_HASH_SIZE; ++h)
                INIT_HLIST_HEAD(&vn->sock_list[h]);

        return 0;
}

static __net_exit void vxlan_exit_net(struct net *net)
{
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        struct vxlan_dev *vxlan;
        LIST_HEAD(list);

        rtnl_lock();
        list_for_each_entry(vxlan, &vn->vxlan_list, next)
                unregister_netdevice_queue(vxlan->dev, &list);
        unregister_netdevice_many(&list);
        rtnl_unlock();
}

static struct pernet_operations vxlan_net_ops = {
        .init = vxlan_init_net,
        .exit = vxlan_exit_net,
        .id   = &vxlan_net_id,
        .size = sizeof(struct vxlan_net),
};

static int __init vxlan_init_module(void)
{
        int rc;

        vxlan_wq = alloc_workqueue("vxlan", 0, 0);
        if (!vxlan_wq)
                return -ENOMEM;

        get_random_bytes(&vxlan_salt, sizeof(vxlan_salt));

        rc = register_pernet_device(&vxlan_net_ops);
        if (rc)
                goto out1;

        rc = rtnl_link_register(&vxlan_link_ops);
        if (rc)
                goto out2;

        return 0;

out2:
        unregister_pernet_device(&vxlan_net_ops);
out1:
        destroy_workqueue(vxlan_wq);
        return rc;
}
late_initcall(vxlan_init_module);

static void __exit vxlan_cleanup_module(void)
{
        rtnl_link_unregister(&vxlan_link_ops);
        destroy_workqueue(vxlan_wq);
        unregister_pernet_device(&vxlan_net_ops);
        rcu_barrier();
}
module_exit(vxlan_cleanup_module);

MODULE_LICENSE("GPL");
MODULE_VERSION(VXLAN_VERSION);
MODULE_AUTHOR("Stephen Hemminger <stephen@networkplumber.org>");
MODULE_ALIAS_RTNL_LINK("vxlan");