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

  /*
   * GENEVE: Generic Network Virtualization Encapsulation
   *
   * Copyright (c) 2015 Red Hat, Inc.

   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/kernel.h>
  #include <linux/module.h>

  #include <linux/etherdevice.h>
  #include <linux/hash.h>

  #include <net/ipv6_stubs.h>

  #include <net/dst_metadata.h>

  #include <net/gro_cells.h>

  #include <net/rtnetlink.h>
  #include <net/geneve.h>

  #include <net/protocol.h>

  
  #define GENEVE_NETDEV_VER	"0.6"

  #define GENEVE_N_VID		(1u << 24)
  #define GENEVE_VID_MASK		(GENEVE_N_VID - 1)
  
  #define VNI_HASH_BITS		10
  #define VNI_HASH_SIZE		(1<<VNI_HASH_BITS)
  
  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");

  #define GENEVE_VER 0
  #define GENEVE_BASE_HLEN (sizeof(struct udphdr) + sizeof(struct genevehdr))

  #define GENEVE_IPV4_HLEN (ETH_HLEN + sizeof(struct iphdr) + GENEVE_BASE_HLEN)
  #define GENEVE_IPV6_HLEN (ETH_HLEN + sizeof(struct ipv6hdr) + GENEVE_BASE_HLEN)

  /* per-network namespace private data for this module */
  struct geneve_net {

  	struct list_head	geneve_list;

  	struct list_head	sock_list;

  };

  static unsigned int geneve_net_id;

  struct geneve_dev_node {
  	struct hlist_node hlist;
  	struct geneve_dev *geneve;
  };

  /* Pseudo network device */
  struct geneve_dev {

  	struct geneve_dev_node hlist4;	/* vni hash table for IPv4 socket */
  #if IS_ENABLED(CONFIG_IPV6)
  	struct geneve_dev_node hlist6;	/* vni hash table for IPv6 socket */
  #endif

  	struct net	   *net;	/* netns for packet i/o */
  	struct net_device  *dev;	/* netdev for geneve tunnel */

  	struct ip_tunnel_info info;

  	struct geneve_sock __rcu *sock4;	/* IPv4 socket used for geneve tunnel */

  #if IS_ENABLED(CONFIG_IPV6)

  	struct geneve_sock __rcu *sock6;	/* IPv6 socket used for geneve tunnel */

  #endif

  	struct list_head   next;	/* geneve's per namespace list */

  	struct gro_cells   gro_cells;

  	bool		   collect_md;
  	bool		   use_udp6_rx_checksums;

  	bool		   ttl_inherit;

  	enum ifla_geneve_df df;

  };

  struct geneve_sock {
  	bool			collect_md;

  	struct list_head	list;
  	struct socket		*sock;
  	struct rcu_head		rcu;
  	int			refcnt;

  	struct hlist_head	vni_list[VNI_HASH_SIZE];

  };

  
  static inline __u32 geneve_net_vni_hash(u8 vni[3])
  {
  	__u32 vnid;
  
  	vnid = (vni[0] << 16) | (vni[1] << 8) | vni[2];
  	return hash_32(vnid, VNI_HASH_BITS);
  }

  static __be64 vni_to_tunnel_id(const __u8 *vni)
  {
  #ifdef __BIG_ENDIAN
  	return (vni[0] << 16) | (vni[1] << 8) | vni[2];
  #else
  	return (__force __be64)(((__force u64)vni[0] << 40) |
  				((__force u64)vni[1] << 48) |
  				((__force u64)vni[2] << 56));
  #endif
  }

  /* Convert 64 bit tunnel ID to 24 bit VNI. */
  static void tunnel_id_to_vni(__be64 tun_id, __u8 *vni)
  {
  #ifdef __BIG_ENDIAN
  	vni[0] = (__force __u8)(tun_id >> 16);
  	vni[1] = (__force __u8)(tun_id >> 8);
  	vni[2] = (__force __u8)tun_id;
  #else
  	vni[0] = (__force __u8)((__force u64)tun_id >> 40);
  	vni[1] = (__force __u8)((__force u64)tun_id >> 48);
  	vni[2] = (__force __u8)((__force u64)tun_id >> 56);
  #endif
  }

  static bool eq_tun_id_and_vni(u8 *tun_id, u8 *vni)
  {

  	return !memcmp(vni, &tun_id[5], 3);

  }

  static sa_family_t geneve_get_sk_family(struct geneve_sock *gs)
  {
  	return gs->sock->sk->sk_family;
  }

  static struct geneve_dev *geneve_lookup(struct geneve_sock *gs,

  					__be32 addr, u8 vni[])

  {

  	struct hlist_head *vni_list_head;

  	struct geneve_dev_node *node;

  	__u32 hash;

  	/* Find the device for this VNI */

  	hash = geneve_net_vni_hash(vni);

  	vni_list_head = &gs->vni_list[hash];

  	hlist_for_each_entry_rcu(node, vni_list_head, hlist) {
  		if (eq_tun_id_and_vni((u8 *)&node->geneve->info.key.tun_id, vni) &&
  		    addr == node->geneve->info.key.u.ipv4.dst)
  			return node->geneve;

  	}
  	return NULL;
  }
  
  #if IS_ENABLED(CONFIG_IPV6)
  static struct geneve_dev *geneve6_lookup(struct geneve_sock *gs,
  					 struct in6_addr addr6, u8 vni[])
  {
  	struct hlist_head *vni_list_head;

  	struct geneve_dev_node *node;

  	__u32 hash;
  
  	/* Find the device for this VNI */
  	hash = geneve_net_vni_hash(vni);
  	vni_list_head = &gs->vni_list[hash];

  	hlist_for_each_entry_rcu(node, vni_list_head, hlist) {
  		if (eq_tun_id_and_vni((u8 *)&node->geneve->info.key.tun_id, vni) &&
  		    ipv6_addr_equal(&addr6, &node->geneve->info.key.u.ipv6.dst))
  			return node->geneve;

  	}

  	return NULL;
  }

  #endif

  static inline struct genevehdr *geneve_hdr(const struct sk_buff *skb)
  {
  	return (struct genevehdr *)(udp_hdr(skb) + 1);
  }

  static struct geneve_dev *geneve_lookup_skb(struct geneve_sock *gs,
  					    struct sk_buff *skb)

  {

  	static u8 zero_vni[3];

  	u8 *vni;

  	if (geneve_get_sk_family(gs) == AF_INET) {

  		struct iphdr *iph;

  		__be32 addr;

  		iph = ip_hdr(skb); /* outer IP header... */

  		if (gs->collect_md) {
  			vni = zero_vni;
  			addr = 0;
  		} else {

  			vni = geneve_hdr(skb)->vni;

  			addr = iph->saddr;
  		}

  		return geneve_lookup(gs, addr, vni);

  #if IS_ENABLED(CONFIG_IPV6)

  	} else if (geneve_get_sk_family(gs) == AF_INET6) {

  		static struct in6_addr zero_addr6;

  		struct ipv6hdr *ip6h;
  		struct in6_addr addr6;

  		ip6h = ipv6_hdr(skb); /* outer IPv6 header... */

  		if (gs->collect_md) {
  			vni = zero_vni;
  			addr6 = zero_addr6;
  		} else {

  			vni = geneve_hdr(skb)->vni;

  			addr6 = ip6h->saddr;
  		}

  		return geneve6_lookup(gs, addr6, vni);

  #endif
  	}

  	return NULL;
  }
  
  /* geneve receive/decap routine */
  static void geneve_rx(struct geneve_dev *geneve, struct geneve_sock *gs,
  		      struct sk_buff *skb)
  {
  	struct genevehdr *gnvh = geneve_hdr(skb);
  	struct metadata_dst *tun_dst = NULL;
  	struct pcpu_sw_netstats *stats;

  	unsigned int len;

  	int err = 0;
  	void *oiph;

  	if (ip_tunnel_collect_metadata() || gs->collect_md) {

  		__be16 flags;

  
  		flags = TUNNEL_KEY | TUNNEL_GENEVE_OPT |
  			(gnvh->oam ? TUNNEL_OAM : 0) |
  			(gnvh->critical ? TUNNEL_CRIT_OPT : 0);

  		tun_dst = udp_tun_rx_dst(skb, geneve_get_sk_family(gs), flags,

  					 vni_to_tunnel_id(gnvh->vni),
  					 gnvh->opt_len * 4);

  		if (!tun_dst) {
  			geneve->dev->stats.rx_dropped++;

  			goto drop;

  		}

  		/* Update tunnel dst according to Geneve options. */

  		ip_tunnel_info_opts_set(&tun_dst->u.tun_info,

  					gnvh->options, gnvh->opt_len * 4,
  					TUNNEL_GENEVE_OPT);

  	} else {
  		/* Drop packets w/ critical options,
  		 * since we don't support any...
  		 */

  		if (gnvh->critical) {
  			geneve->dev->stats.rx_frame_errors++;
  			geneve->dev->stats.rx_errors++;

  			goto drop;

  		}

  	}

  
  	skb_reset_mac_header(skb);

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

  	if (tun_dst)
  		skb_dst_set(skb, &tun_dst->dst);

  	/* Ignore packet loops (and multicast echo) */

  	if (ether_addr_equal(eth_hdr(skb)->h_source, geneve->dev->dev_addr)) {
  		geneve->dev->stats.rx_errors++;

  		goto drop;

  	}

  	oiph = skb_network_header(skb);

  	skb_reset_network_header(skb);

  	if (geneve_get_sk_family(gs) == AF_INET)
  		err = IP_ECN_decapsulate(oiph, skb);

  #if IS_ENABLED(CONFIG_IPV6)

  	else
  		err = IP6_ECN_decapsulate(oiph, skb);

  #endif

  
  	if (unlikely(err)) {

  		if (log_ecn_error) {

  			if (geneve_get_sk_family(gs) == AF_INET)

  				net_info_ratelimited("non-ECT from %pI4 "
  						     "with TOS=%#x
  ",

  						     &((struct iphdr *)oiph)->saddr,
  						     ((struct iphdr *)oiph)->tos);

  #if IS_ENABLED(CONFIG_IPV6)

  			else

  				net_info_ratelimited("non-ECT from %pI6
  ",

  						     &((struct ipv6hdr *)oiph)->saddr);

  #endif
  		}

  		if (err > 1) {
  			++geneve->dev->stats.rx_frame_errors;
  			++geneve->dev->stats.rx_errors;
  			goto drop;
  		}
  	}

  	len = skb->len;
  	err = gro_cells_receive(&geneve->gro_cells, skb);
  	if (likely(err == NET_RX_SUCCESS)) {
  		stats = this_cpu_ptr(geneve->dev->tstats);
  		u64_stats_update_begin(&stats->syncp);
  		stats->rx_packets++;
  		stats->rx_bytes += len;
  		u64_stats_update_end(&stats->syncp);
  	}

  	return;
  drop:
  	/* Consume bad packet */
  	kfree_skb(skb);
  }
  
  /* Setup stats when device is created */
  static int geneve_init(struct net_device *dev)
  {

  	struct geneve_dev *geneve = netdev_priv(dev);
  	int err;

  	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
  	if (!dev->tstats)
  		return -ENOMEM;

  
  	err = gro_cells_init(&geneve->gro_cells, dev);
  	if (err) {
  		free_percpu(dev->tstats);
  		return err;
  	}

  	err = dst_cache_init(&geneve->info.dst_cache, GFP_KERNEL);

  	if (err) {
  		free_percpu(dev->tstats);
  		gro_cells_destroy(&geneve->gro_cells);
  		return err;
  	}

  	return 0;
  }
  
  static void geneve_uninit(struct net_device *dev)
  {

  	struct geneve_dev *geneve = netdev_priv(dev);

  	dst_cache_destroy(&geneve->info.dst_cache);

  	gro_cells_destroy(&geneve->gro_cells);

  	free_percpu(dev->tstats);
  }

  /* Callback from net/ipv4/udp.c to receive packets */
  static int geneve_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
  {
  	struct genevehdr *geneveh;

  	struct geneve_dev *geneve;

  	struct geneve_sock *gs;
  	int opts_len;

  	/* Need UDP and Geneve header to be present */

  	if (unlikely(!pskb_may_pull(skb, GENEVE_BASE_HLEN)))

  		goto drop;

  
  	/* Return packets with reserved bits set */
  	geneveh = geneve_hdr(skb);
  	if (unlikely(geneveh->ver != GENEVE_VER))

  		goto drop;

  
  	if (unlikely(geneveh->proto_type != htons(ETH_P_TEB)))

  		goto drop;

  	gs = rcu_dereference_sk_user_data(sk);
  	if (!gs)
  		goto drop;
  
  	geneve = geneve_lookup_skb(gs, skb);
  	if (!geneve)
  		goto drop;

  	opts_len = geneveh->opt_len * 4;
  	if (iptunnel_pull_header(skb, GENEVE_BASE_HLEN + opts_len,

  				 htons(ETH_P_TEB),

  				 !net_eq(geneve->net, dev_net(geneve->dev)))) {
  		geneve->dev->stats.rx_dropped++;

  		goto drop;

  	}

  	geneve_rx(geneve, gs, skb);

  	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 tunnel for errors */
  static int geneve_udp_encap_err_lookup(struct sock *sk, struct sk_buff *skb)
  {
  	struct genevehdr *geneveh;
  	struct geneve_sock *gs;
  	u8 zero_vni[3] = { 0 };
  	u8 *vni = zero_vni;

  	if (!pskb_may_pull(skb, skb_transport_offset(skb) + GENEVE_BASE_HLEN))

  		return -EINVAL;
  
  	geneveh = geneve_hdr(skb);
  	if (geneveh->ver != GENEVE_VER)
  		return -EINVAL;
  
  	if (geneveh->proto_type != htons(ETH_P_TEB))
  		return -EINVAL;
  
  	gs = rcu_dereference_sk_user_data(sk);
  	if (!gs)
  		return -ENOENT;
  
  	if (geneve_get_sk_family(gs) == AF_INET) {
  		struct iphdr *iph = ip_hdr(skb);
  		__be32 addr4 = 0;
  
  		if (!gs->collect_md) {
  			vni = geneve_hdr(skb)->vni;
  			addr4 = iph->daddr;
  		}
  
  		return geneve_lookup(gs, addr4, vni) ? 0 : -ENOENT;
  	}
  
  #if IS_ENABLED(CONFIG_IPV6)
  	if (geneve_get_sk_family(gs) == AF_INET6) {
  		struct ipv6hdr *ip6h = ipv6_hdr(skb);

  		struct in6_addr addr6;
  
  		memset(&addr6, 0, sizeof(struct in6_addr));

  
  		if (!gs->collect_md) {
  			vni = geneve_hdr(skb)->vni;
  			addr6 = ip6h->daddr;
  		}
  
  		return geneve6_lookup(gs, addr6, vni) ? 0 : -ENOENT;
  	}
  #endif
  
  	return -EPFNOSUPPORT;
  }

  static struct socket *geneve_create_sock(struct net *net, bool ipv6,

  					 __be16 port, bool ipv6_rx_csum)

  {
  	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.ipv6_v6only = 1;

  		udp_conf.use_udp6_rx_checksums = ipv6_rx_csum;

  	} else {
  		udp_conf.family = AF_INET;
  		udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
  	}
  
  	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;
  }

  static int geneve_hlen(struct genevehdr *gh)
  {
  	return sizeof(*gh) + gh->opt_len * 4;
  }

  static struct sk_buff *geneve_gro_receive(struct sock *sk,
  					  struct list_head *head,
  					  struct sk_buff *skb)

  {

  	struct sk_buff *pp = NULL;
  	struct sk_buff *p;

  	struct genevehdr *gh, *gh2;
  	unsigned int hlen, gh_len, off_gnv;
  	const struct packet_offload *ptype;
  	__be16 type;
  	int flush = 1;
  
  	off_gnv = skb_gro_offset(skb);
  	hlen = off_gnv + sizeof(*gh);
  	gh = skb_gro_header_fast(skb, off_gnv);
  	if (skb_gro_header_hard(skb, hlen)) {
  		gh = skb_gro_header_slow(skb, hlen, off_gnv);
  		if (unlikely(!gh))
  			goto out;
  	}
  
  	if (gh->ver != GENEVE_VER || gh->oam)
  		goto out;
  	gh_len = geneve_hlen(gh);
  
  	hlen = off_gnv + gh_len;
  	if (skb_gro_header_hard(skb, hlen)) {
  		gh = skb_gro_header_slow(skb, hlen, off_gnv);
  		if (unlikely(!gh))
  			goto out;
  	}

  	list_for_each_entry(p, head, list) {

  		if (!NAPI_GRO_CB(p)->same_flow)
  			continue;
  
  		gh2 = (struct genevehdr *)(p->data + off_gnv);
  		if (gh->opt_len != gh2->opt_len ||
  		    memcmp(gh, gh2, gh_len)) {
  			NAPI_GRO_CB(p)->same_flow = 0;
  			continue;
  		}
  	}
  
  	type = gh->proto_type;
  
  	rcu_read_lock();
  	ptype = gro_find_receive_by_type(type);

  	if (!ptype)

  		goto out_unlock;

  
  	skb_gro_pull(skb, gh_len);
  	skb_gro_postpull_rcsum(skb, gh, gh_len);

  	pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb);

  	flush = 0;

  
  out_unlock:
  	rcu_read_unlock();
  out:

  	skb_gro_flush_final(skb, pp, flush);

  
  	return pp;
  }

  static int geneve_gro_complete(struct sock *sk, struct sk_buff *skb,
  			       int nhoff)

  {
  	struct genevehdr *gh;
  	struct packet_offload *ptype;
  	__be16 type;
  	int gh_len;
  	int err = -ENOSYS;

  	gh = (struct genevehdr *)(skb->data + nhoff);
  	gh_len = geneve_hlen(gh);
  	type = gh->proto_type;
  
  	rcu_read_lock();
  	ptype = gro_find_complete_by_type(type);
  	if (ptype)
  		err = ptype->callbacks.gro_complete(skb, nhoff + gh_len);
  
  	rcu_read_unlock();

  
  	skb_set_inner_mac_header(skb, nhoff + gh_len);

  	return err;
  }
  
  /* Create new listen socket if needed */
  static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port,

  						bool ipv6, bool ipv6_rx_csum)

  {
  	struct geneve_net *gn = net_generic(net, geneve_net_id);
  	struct geneve_sock *gs;
  	struct socket *sock;
  	struct udp_tunnel_sock_cfg tunnel_cfg;

  	int h;

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

  	sock = geneve_create_sock(net, ipv6, port, ipv6_rx_csum);

  	if (IS_ERR(sock)) {
  		kfree(gs);
  		return ERR_CAST(sock);
  	}
  
  	gs->sock = sock;
  	gs->refcnt = 1;

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

  
  	/* Initialize the geneve udp offloads structure */

  	udp_tunnel_notify_add_rx_port(gs->sock, UDP_TUNNEL_TYPE_GENEVE);

  
  	/* Mark socket as an encapsulation socket */

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

  	tunnel_cfg.sk_user_data = gs;
  	tunnel_cfg.encap_type = 1;

  	tunnel_cfg.gro_receive = geneve_gro_receive;
  	tunnel_cfg.gro_complete = geneve_gro_complete;

  	tunnel_cfg.encap_rcv = geneve_udp_encap_recv;

  	tunnel_cfg.encap_err_lookup = geneve_udp_encap_err_lookup;

  	tunnel_cfg.encap_destroy = NULL;
  	setup_udp_tunnel_sock(net, sock, &tunnel_cfg);

  	list_add(&gs->list, &gn->sock_list);
  	return gs;
  }

  static void __geneve_sock_release(struct geneve_sock *gs)

  {

  	if (!gs || --gs->refcnt)

  		return;
  
  	list_del(&gs->list);

  	udp_tunnel_notify_del_rx_port(gs->sock, UDP_TUNNEL_TYPE_GENEVE);

  	udp_tunnel_sock_release(gs->sock);
  	kfree_rcu(gs, rcu);
  }

  static void geneve_sock_release(struct geneve_dev *geneve)
  {

  	struct geneve_sock *gs4 = rtnl_dereference(geneve->sock4);

  #if IS_ENABLED(CONFIG_IPV6)

  	struct geneve_sock *gs6 = rtnl_dereference(geneve->sock6);
  
  	rcu_assign_pointer(geneve->sock6, NULL);
  #endif
  
  	rcu_assign_pointer(geneve->sock4, NULL);
  	synchronize_net();
  
  	__geneve_sock_release(gs4);
  #if IS_ENABLED(CONFIG_IPV6)
  	__geneve_sock_release(gs6);

  #endif
  }

  static struct geneve_sock *geneve_find_sock(struct geneve_net *gn,

  					    sa_family_t family,

  					    __be16 dst_port)
  {
  	struct geneve_sock *gs;
  
  	list_for_each_entry(gs, &gn->sock_list, list) {
  		if (inet_sk(gs->sock->sk)->inet_sport == dst_port &&

  		    geneve_get_sk_family(gs) == family) {

  			return gs;
  		}
  	}
  	return NULL;
  }

  static int geneve_sock_add(struct geneve_dev *geneve, bool ipv6)

  {

  	struct net *net = geneve->net;

  	struct geneve_net *gn = net_generic(net, geneve_net_id);

  	struct geneve_dev_node *node;

  	struct geneve_sock *gs;

  	__u8 vni[3];

  	__u32 hash;

  	gs = geneve_find_sock(gn, ipv6 ? AF_INET6 : AF_INET, geneve->info.key.tp_dst);

  	if (gs) {
  		gs->refcnt++;
  		goto out;
  	}

  	gs = geneve_socket_create(net, geneve->info.key.tp_dst, ipv6,
  				  geneve->use_udp6_rx_checksums);

  	if (IS_ERR(gs))
  		return PTR_ERR(gs);

  out:
  	gs->collect_md = geneve->collect_md;

  #if IS_ENABLED(CONFIG_IPV6)

  	if (ipv6) {

  		rcu_assign_pointer(geneve->sock6, gs);

  		node = &geneve->hlist6;
  	} else

  #endif

  	{

  		rcu_assign_pointer(geneve->sock4, gs);

  		node = &geneve->hlist4;
  	}
  	node->geneve = geneve;

  	tunnel_id_to_vni(geneve->info.key.tun_id, vni);
  	hash = geneve_net_vni_hash(vni);

  	hlist_add_head_rcu(&node->hlist, &gs->vni_list[hash]);

  	return 0;
  }

  static int geneve_open(struct net_device *dev)
  {
  	struct geneve_dev *geneve = netdev_priv(dev);

  	bool metadata = geneve->collect_md;

  	bool ipv4, ipv6;

  	int ret = 0;

  	ipv6 = geneve->info.mode & IP_TUNNEL_INFO_IPV6 || metadata;
  	ipv4 = !ipv6 || metadata;

  #if IS_ENABLED(CONFIG_IPV6)

  	if (ipv6) {

  		ret = geneve_sock_add(geneve, true);

  		if (ret < 0 && ret != -EAFNOSUPPORT)
  			ipv4 = false;
  	}

  #endif

  	if (ipv4)

  		ret = geneve_sock_add(geneve, false);
  	if (ret < 0)
  		geneve_sock_release(geneve);
  
  	return ret;
  }

  static int geneve_stop(struct net_device *dev)
  {
  	struct geneve_dev *geneve = netdev_priv(dev);

  	hlist_del_init_rcu(&geneve->hlist4.hlist);
  #if IS_ENABLED(CONFIG_IPV6)
  	hlist_del_init_rcu(&geneve->hlist6.hlist);
  #endif

  	geneve_sock_release(geneve);

  	return 0;
  }

  static void geneve_build_header(struct genevehdr *geneveh,

  				const struct ip_tunnel_info *info)

  {
  	geneveh->ver = GENEVE_VER;

  	geneveh->opt_len = info->options_len / 4;
  	geneveh->oam = !!(info->key.tun_flags & TUNNEL_OAM);
  	geneveh->critical = !!(info->key.tun_flags & TUNNEL_CRIT_OPT);

  	geneveh->rsvd1 = 0;

  	tunnel_id_to_vni(info->key.tun_id, geneveh->vni);

  	geneveh->proto_type = htons(ETH_P_TEB);
  	geneveh->rsvd2 = 0;

  	if (info->key.tun_flags & TUNNEL_GENEVE_OPT)
  		ip_tunnel_info_opts_get(geneveh->options, info);

  }

  static int geneve_build_skb(struct dst_entry *dst, struct sk_buff *skb,
  			    const struct ip_tunnel_info *info,
  			    bool xnet, int ip_hdr_len)

  {

  	bool udp_sum = !!(info->key.tun_flags & TUNNEL_CSUM);

  	struct genevehdr *gnvh;
  	int min_headroom;
  	int err;

  	skb_reset_mac_header(skb);

  	skb_scrub_packet(skb, xnet);

  	min_headroom = LL_RESERVED_SPACE(dst->dev) + dst->header_len +
  		       GENEVE_BASE_HLEN + info->options_len + ip_hdr_len;

  	err = skb_cow_head(skb, min_headroom);

  	if (unlikely(err))

  		goto free_dst;

  	err = udp_tunnel_handle_offloads(skb, udp_sum);

  	if (err)

  		goto free_dst;

  	gnvh = __skb_push(skb, sizeof(*gnvh) + info->options_len);

  	geneve_build_header(gnvh, info);

  	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
  	return 0;
  
  free_dst:
  	dst_release(dst);
  	return err;
  }

  
  static struct rtable *geneve_get_v4_rt(struct sk_buff *skb,
  				       struct net_device *dev,

  				       struct geneve_sock *gs4,

  				       struct flowi4 *fl4,

  				       const struct ip_tunnel_info *info)

  {

  	bool use_cache = ip_tunnel_dst_cache_usable(skb, info);

  	struct geneve_dev *geneve = netdev_priv(dev);

  	struct dst_cache *dst_cache;

  	struct rtable *rt = NULL;
  	__u8 tos;

  	if (!gs4)

  		return ERR_PTR(-EIO);

  	memset(fl4, 0, sizeof(*fl4));
  	fl4->flowi4_mark = skb->mark;
  	fl4->flowi4_proto = IPPROTO_UDP;

  	fl4->daddr = info->key.u.ipv4.dst;
  	fl4->saddr = info->key.u.ipv4.src;

  	tos = info->key.tos;
  	if ((tos == 1) && !geneve->collect_md) {
  		tos = ip_tunnel_get_dsfield(ip_hdr(skb), skb);
  		use_cache = false;

  	}

  	fl4->flowi4_tos = RT_TOS(tos);

  	dst_cache = (struct dst_cache *)&info->dst_cache;

  	if (use_cache) {
  		rt = dst_cache_get_ip4(dst_cache, &fl4->saddr);
  		if (rt)
  			return rt;

  	}

  	rt = ip_route_output_key(geneve->net, fl4);
  	if (IS_ERR(rt)) {
  		netdev_dbg(dev, "no route to %pI4
  ", &fl4->daddr);

  		return ERR_PTR(-ENETUNREACH);

  	}
  	if (rt->dst.dev == dev) { /* is this necessary? */
  		netdev_dbg(dev, "circular route to %pI4
  ", &fl4->daddr);

  		ip_rt_put(rt);

  		return ERR_PTR(-ELOOP);

  	}

  	if (use_cache)
  		dst_cache_set_ip4(dst_cache, &rt->dst, fl4->saddr);

  	return rt;
  }

  #if IS_ENABLED(CONFIG_IPV6)
  static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
  					   struct net_device *dev,

  					   struct geneve_sock *gs6,

  					   struct flowi6 *fl6,

  					   const struct ip_tunnel_info *info)

  {

  	bool use_cache = ip_tunnel_dst_cache_usable(skb, info);

  	struct geneve_dev *geneve = netdev_priv(dev);

  	struct dst_entry *dst = NULL;

  	struct dst_cache *dst_cache;

  	__u8 prio;

  	if (!gs6)
  		return ERR_PTR(-EIO);

  	memset(fl6, 0, sizeof(*fl6));
  	fl6->flowi6_mark = skb->mark;
  	fl6->flowi6_proto = IPPROTO_UDP;

  	fl6->daddr = info->key.u.ipv6.dst;
  	fl6->saddr = info->key.u.ipv6.src;
  	prio = info->key.tos;
  	if ((prio == 1) && !geneve->collect_md) {
  		prio = ip_tunnel_get_dsfield(ip_hdr(skb), skb);
  		use_cache = false;

  	}

  	fl6->flowlabel = ip6_make_flowinfo(RT_TOS(prio),
  					   info->key.label);

  	dst_cache = (struct dst_cache *)&info->dst_cache;

  	if (use_cache) {
  		dst = dst_cache_get_ip6(dst_cache, &fl6->saddr);
  		if (dst)
  			return dst;

  	}

  	dst = ipv6_stub->ipv6_dst_lookup_flow(geneve->net, gs6->sock->sk, fl6,
  					      NULL);
  	if (IS_ERR(dst)) {

  		netdev_dbg(dev, "no route to %pI6
  ", &fl6->daddr);
  		return ERR_PTR(-ENETUNREACH);
  	}
  	if (dst->dev == dev) { /* is this necessary? */
  		netdev_dbg(dev, "circular route to %pI6
  ", &fl6->daddr);
  		dst_release(dst);
  		return ERR_PTR(-ELOOP);
  	}

  	if (use_cache)
  		dst_cache_set_ip6(dst_cache, dst, &fl6->saddr);

  	return dst;
  }
  #endif

  static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,

  			   struct geneve_dev *geneve,
  			   const struct ip_tunnel_info *info)

  {

  	bool xnet = !net_eq(geneve->net, dev_net(geneve->dev));
  	struct geneve_sock *gs4 = rcu_dereference(geneve->sock4);
  	const struct ip_tunnel_key *key = &info->key;
  	struct rtable *rt;

  	struct flowi4 fl4;

  	__u8 tos, ttl;

  	__be16 df = 0;

  	__be16 sport;

  	int err;

  	rt = geneve_get_v4_rt(skb, dev, gs4, &fl4, info);

  	if (IS_ERR(rt))
  		return PTR_ERR(rt);

  	skb_tunnel_check_pmtu(skb, &rt->dst,
  			      GENEVE_IPV4_HLEN + info->options_len);

  	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);

  	if (geneve->collect_md) {
  		tos = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb);

  		ttl = key->ttl;

  
  		df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;

  	} else {

  		tos = ip_tunnel_ecn_encap(fl4.flowi4_tos, ip_hdr(skb), skb);

  		if (geneve->ttl_inherit)
  			ttl = ip_tunnel_get_ttl(ip_hdr(skb), skb);
  		else
  			ttl = key->ttl;
  		ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);

  
  		if (geneve->df == GENEVE_DF_SET) {
  			df = htons(IP_DF);
  		} else if (geneve->df == GENEVE_DF_INHERIT) {
  			struct ethhdr *eth = eth_hdr(skb);
  
  			if (ntohs(eth->h_proto) == ETH_P_IPV6) {
  				df = htons(IP_DF);
  			} else if (ntohs(eth->h_proto) == ETH_P_IP) {
  				struct iphdr *iph = ip_hdr(skb);
  
  				if (iph->frag_off & htons(IP_DF))
  					df = htons(IP_DF);
  			}
  		}

  	}

  	err = geneve_build_skb(&rt->dst, skb, info, xnet, sizeof(struct iphdr));

  	if (unlikely(err))
  		return err;

  	udp_tunnel_xmit_skb(rt, gs4->sock->sk, skb, fl4.saddr, fl4.daddr,
  			    tos, ttl, df, sport, geneve->info.key.tp_dst,
  			    !net_eq(geneve->net, dev_net(geneve->dev)),
  			    !(info->key.tun_flags & TUNNEL_CSUM));
  	return 0;

  }

  #if IS_ENABLED(CONFIG_IPV6)

  static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,

  			    struct geneve_dev *geneve,
  			    const struct ip_tunnel_info *info)

  {

  	bool xnet = !net_eq(geneve->net, dev_net(geneve->dev));
  	struct geneve_sock *gs6 = rcu_dereference(geneve->sock6);
  	const struct ip_tunnel_key *key = &info->key;

  	struct dst_entry *dst = NULL;

  	struct flowi6 fl6;

  	__u8 prio, ttl;

  	__be16 sport;

  	int err;

  	dst = geneve_get_v6_dst(skb, dev, gs6, &fl6, info);

  	if (IS_ERR(dst))
  		return PTR_ERR(dst);

  	skb_tunnel_check_pmtu(skb, dst, GENEVE_IPV6_HLEN + info->options_len);

  	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);

  	if (geneve->collect_md) {
  		prio = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb);
  		ttl = key->ttl;
  	} else {
  		prio = ip_tunnel_ecn_encap(ip6_tclass(fl6.flowlabel),
  					   ip_hdr(skb), skb);

  		if (geneve->ttl_inherit)
  			ttl = ip_tunnel_get_ttl(ip_hdr(skb), skb);
  		else
  			ttl = key->ttl;
  		ttl = ttl ? : ip6_dst_hoplimit(dst);

  	}

  	err = geneve_build_skb(dst, skb, info, xnet, sizeof(struct ipv6hdr));

  	if (unlikely(err))
  		return err;

  	udp_tunnel6_xmit_skb(dst, gs6->sock->sk, skb, dev,
  			     &fl6.saddr, &fl6.daddr, prio, ttl,
  			     info->key.label, sport, geneve->info.key.tp_dst,
  			     !(info->key.tun_flags & TUNNEL_CSUM));
  	return 0;
  }
  #endif

  static netdev_tx_t geneve_xmit(struct sk_buff *skb, struct net_device *dev)
  {
  	struct geneve_dev *geneve = netdev_priv(dev);
  	struct ip_tunnel_info *info = NULL;
  	int err;

  	if (geneve->collect_md) {
  		info = skb_tunnel_info(skb);
  		if (unlikely(!info || !(info->mode & IP_TUNNEL_INFO_TX))) {
  			err = -EINVAL;
  			netdev_dbg(dev, "no tunnel metadata
  ");

  			goto tx_error;

  		}

  	} else {

  		info = &geneve->info;

  	}

  	rcu_read_lock();

  #if IS_ENABLED(CONFIG_IPV6)
  	if (info->mode & IP_TUNNEL_INFO_IPV6)
  		err = geneve6_xmit_skb(skb, dev, geneve, info);
  	else
  #endif
  		err = geneve_xmit_skb(skb, dev, geneve, info);

  	rcu_read_unlock();

  	if (likely(!err))
  		return NETDEV_TX_OK;

  tx_error:
  	dev_kfree_skb(skb);

  	if (err == -ELOOP)
  		dev->stats.collisions++;
  	else if (err == -ENETUNREACH)
  		dev->stats.tx_carrier_errors++;

  
  	dev->stats.tx_errors++;

  	return NETDEV_TX_OK;
  }

  static int geneve_change_mtu(struct net_device *dev, int new_mtu)

  {

  	if (new_mtu > dev->max_mtu)
  		new_mtu = dev->max_mtu;

  	else if (new_mtu < dev->min_mtu)
  		new_mtu = dev->min_mtu;

  	dev->mtu = new_mtu;
  	return 0;
  }

  static int geneve_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
  {
  	struct ip_tunnel_info *info = skb_tunnel_info(skb);
  	struct geneve_dev *geneve = netdev_priv(dev);

  	if (ip_tunnel_info_af(info) == AF_INET) {

  		struct rtable *rt;
  		struct flowi4 fl4;

  		struct geneve_sock *gs4 = rcu_dereference(geneve->sock4);

  		rt = geneve_get_v4_rt(skb, dev, gs4, &fl4, info);

  		if (IS_ERR(rt))
  			return PTR_ERR(rt);

  		ip_rt_put(rt);
  		info->key.u.ipv4.src = fl4.saddr;
  #if IS_ENABLED(CONFIG_IPV6)
  	} else if (ip_tunnel_info_af(info) == AF_INET6) {

  		struct dst_entry *dst;
  		struct flowi6 fl6;

  		struct geneve_sock *gs6 = rcu_dereference(geneve->sock6);

  		dst = geneve_get_v6_dst(skb, dev, gs6, &fl6, info);

  		if (IS_ERR(dst))
  			return PTR_ERR(dst);
  
  		dst_release(dst);
  		info->key.u.ipv6.src = fl6.saddr;
  #endif
  	} else {
  		return -EINVAL;
  	}

  	info->key.tp_src = udp_flow_src_port(geneve->net, skb,
  					     1, USHRT_MAX, true);

  	info->key.tp_dst = geneve->info.key.tp_dst;

  	return 0;
  }

  static const struct net_device_ops geneve_netdev_ops = {
  	.ndo_init		= geneve_init,
  	.ndo_uninit		= geneve_uninit,
  	.ndo_open		= geneve_open,
  	.ndo_stop		= geneve_stop,
  	.ndo_start_xmit		= geneve_xmit,
  	.ndo_get_stats64	= ip_tunnel_get_stats64,

  	.ndo_change_mtu		= geneve_change_mtu,

  	.ndo_validate_addr	= eth_validate_addr,
  	.ndo_set_mac_address	= eth_mac_addr,

  	.ndo_fill_metadata_dst	= geneve_fill_metadata_dst,

  };
  
  static void geneve_get_drvinfo(struct net_device *dev,
  			       struct ethtool_drvinfo *drvinfo)
  {
  	strlcpy(drvinfo->version, GENEVE_NETDEV_VER, sizeof(drvinfo->version));
  	strlcpy(drvinfo->driver, "geneve", sizeof(drvinfo->driver));
  }
  
  static const struct ethtool_ops geneve_ethtool_ops = {
  	.get_drvinfo	= geneve_get_drvinfo,
  	.get_link	= ethtool_op_get_link,
  };
  
  /* Info for udev, that this is a virtual tunnel endpoint */
  static struct device_type geneve_type = {
  	.name = "geneve",
  };

  /* Calls the ndo_udp_tunnel_add of the caller in order to

   * supply the listening GENEVE udp ports. Callers are expected

   * to implement the ndo_udp_tunnel_add.

   */

  static void geneve_offload_rx_ports(struct net_device *dev, bool push)

  {
  	struct net *net = dev_net(dev);
  	struct geneve_net *gn = net_generic(net, geneve_net_id);
  	struct geneve_sock *gs;

  	rcu_read_lock();

  	list_for_each_entry_rcu(gs, &gn->sock_list, list) {
  		if (push) {
  			udp_tunnel_push_rx_port(dev, gs->sock,
  						UDP_TUNNEL_TYPE_GENEVE);
  		} else {
  			udp_tunnel_drop_rx_port(dev, gs->sock,
  						UDP_TUNNEL_TYPE_GENEVE);
  		}
  	}

  	rcu_read_unlock();
  }

  /* Initialize the device structure. */
  static void geneve_setup(struct net_device *dev)
  {
  	ether_setup(dev);
  
  	dev->netdev_ops = &geneve_netdev_ops;
  	dev->ethtool_ops = &geneve_ethtool_ops;

  	dev->needs_free_netdev = true;

  
  	SET_NETDEV_DEVTYPE(dev, &geneve_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->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_RXCSUM;
  	dev->hw_features |= NETIF_F_GSO_SOFTWARE;

  	/* MTU range: 68 - (something less than 65535) */
  	dev->min_mtu = ETH_MIN_MTU;
  	/* The max_mtu calculation does not take account of GENEVE
  	 * options, to avoid excluding potentially valid
  	 * configurations. This will be further reduced by IPvX hdr size.
  	 */
  	dev->max_mtu = IP_MAX_MTU - GENEVE_BASE_HLEN - dev->hard_header_len;

  	netif_keep_dst(dev);

  	dev->priv_flags &= ~IFF_TX_SKB_SHARING;

  	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE | IFF_NO_QUEUE;

  	eth_hw_addr_random(dev);

  }
  
  static const struct nla_policy geneve_policy[IFLA_GENEVE_MAX + 1] = {
  	[IFLA_GENEVE_ID]		= { .type = NLA_U32 },

  	[IFLA_GENEVE_REMOTE]		= { .len = sizeof_field(struct iphdr, daddr) },

  	[IFLA_GENEVE_REMOTE6]		= { .len = sizeof(struct in6_addr) },

  	[IFLA_GENEVE_TTL]		= { .type = NLA_U8 },

  	[IFLA_GENEVE_TOS]		= { .type = NLA_U8 },

  	[IFLA_GENEVE_LABEL]		= { .type = NLA_U32 },

  	[IFLA_GENEVE_PORT]		= { .type = NLA_U16 },

  	[IFLA_GENEVE_COLLECT_METADATA]	= { .type = NLA_FLAG },

  	[IFLA_GENEVE_UDP_CSUM]		= { .type = NLA_U8 },
  	[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]	= { .type = NLA_U8 },
  	[IFLA_GENEVE_UDP_ZERO_CSUM6_RX]	= { .type = NLA_U8 },

  	[IFLA_GENEVE_TTL_INHERIT]	= { .type = NLA_U8 },

  	[IFLA_GENEVE_DF]		= { .type = NLA_U8 },

  };

  static int geneve_validate(struct nlattr *tb[], struct nlattr *data[],
  			   struct netlink_ext_ack *extack)

  {
  	if (tb[IFLA_ADDRESS]) {

  		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) {
  			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_ADDRESS],
  					    "Provided link layer address is not Ethernet");

  			return -EINVAL;

  		}

  		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) {
  			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_ADDRESS],
  					    "Provided Ethernet address is not unicast");

  			return -EADDRNOTAVAIL;

  		}

  	}

  	if (!data) {
  		NL_SET_ERR_MSG(extack,
  			       "Not enough attributes provided to perform the operation");

  		return -EINVAL;

  	}

  
  	if (data[IFLA_GENEVE_ID]) {
  		__u32 vni =  nla_get_u32(data[IFLA_GENEVE_ID]);

  		if (vni >= GENEVE_N_VID) {
  			NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_ID],
  					    "Geneve ID must be lower than 16777216");

  			return -ERANGE;

  		}

  	}

  	if (data[IFLA_GENEVE_DF]) {
  		enum ifla_geneve_df df = nla_get_u8(data[IFLA_GENEVE_DF]);
  
  		if (df < 0 || df > GENEVE_DF_MAX) {
  			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_GENEVE_DF],
  					    "Invalid DF attribute");
  			return -EINVAL;
  		}
  	}

  	return 0;
  }

  static struct geneve_dev *geneve_find_dev(struct geneve_net *gn,

  					  const struct ip_tunnel_info *info,

  					  bool *tun_on_same_port,
  					  bool *tun_collect_md)
  {

  	struct geneve_dev *geneve, *t = NULL;

  
  	*tun_on_same_port = false;
  	*tun_collect_md = false;

  	list_for_each_entry(geneve, &gn->geneve_list, next) {

  		if (info->key.tp_dst == geneve->info.key.tp_dst) {

  			*tun_collect_md = geneve->collect_md;
  			*tun_on_same_port = true;
  		}

  		if (info->key.tun_id == geneve->info.key.tun_id &&
  		    info->key.tp_dst == geneve->info.key.tp_dst &&
  		    !memcmp(&info->key.u, &geneve->info.key.u, sizeof(info->key.u)))

  			t = geneve;
  	}
  	return t;
  }

  static bool is_tnl_info_zero(const struct ip_tunnel_info *info)
  {

  	return !(info->key.tun_id || info->key.tun_flags || info->key.tos ||
  		 info->key.ttl || info->key.label || info->key.tp_src ||
  		 memchr_inv(&info->key.u, 0, sizeof(info->key.u)));

  }

  static bool geneve_dst_addr_equal(struct ip_tunnel_info *a,
  				  struct ip_tunnel_info *b)
  {
  	if (ip_tunnel_info_af(a) == AF_INET)
  		return a->key.u.ipv4.dst == b->key.u.ipv4.dst;
  	else
  		return ipv6_addr_equal(&a->key.u.ipv6.dst, &b->key.u.ipv6.dst);
  }

  static int geneve_configure(struct net *net, struct net_device *dev,

  			    struct netlink_ext_ack *extack,

  			    const struct ip_tunnel_info *info,

  			    bool metadata, bool ipv6_rx_csum,

  			    bool ttl_inherit, enum ifla_geneve_df df)

  {
  	struct geneve_net *gn = net_generic(net, geneve_net_id);

  	struct geneve_dev *t, *geneve = netdev_priv(dev);
  	bool tun_collect_md, tun_on_same_port;

  	int err, encap_len;

  	if (metadata && !is_tnl_info_zero(info)) {
  		NL_SET_ERR_MSG(extack,
  			       "Device is externally controlled, so attributes (VNI, Port, and so on) must not be specified");

  		return -EINVAL;

  	}

  
  	geneve->net = net;
  	geneve->dev = dev;

  	t = geneve_find_dev(gn, info, &tun_on_same_port, &tun_collect_md);

  	if (t)
  		return -EBUSY;

  	/* make enough headroom for basic scenario */
  	encap_len = GENEVE_BASE_HLEN + ETH_HLEN;

  	if (!metadata && ip_tunnel_info_af(info) == AF_INET) {

  		encap_len += sizeof(struct iphdr);

  		dev->max_mtu -= sizeof(struct iphdr);
  	} else {

  		encap_len += sizeof(struct ipv6hdr);

  		dev->max_mtu -= sizeof(struct ipv6hdr);
  	}

  	dev->needed_headroom = encap_len + ETH_HLEN;

  	if (metadata) {

  		if (tun_on_same_port) {
  			NL_SET_ERR_MSG(extack,
  				       "There can be only one externally controlled device on a destination port");

  			return -EPERM;

  		}

  	} else {

  		if (tun_collect_md) {
  			NL_SET_ERR_MSG(extack,
  				       "There already exists an externally controlled device on this destination port");

  			return -EPERM;

  		}

  	}

  	dst_cache_reset(&geneve->info.dst_cache);
  	geneve->info = *info;
  	geneve->collect_md = metadata;
  	geneve->use_udp6_rx_checksums = ipv6_rx_csum;

  	geneve->ttl_inherit = ttl_inherit;

  	geneve->df = df;

  	err = register_netdevice(dev);
  	if (err)
  		return err;

  	list_add(&geneve->next, &gn->geneve_list);

  	return 0;
  }

  static void init_tnl_info(struct ip_tunnel_info *info, __u16 dst_port)
  {
  	memset(info, 0, sizeof(*info));
  	info->key.tp_dst = htons(dst_port);
  }

  static int geneve_nl2info(struct nlattr *tb[], struct nlattr *data[],
  			  struct netlink_ext_ack *extack,
  			  struct ip_tunnel_info *info, bool *metadata,

  			  bool *use_udp6_rx_checksums, bool *ttl_inherit,

  			  enum ifla_geneve_df *df, bool changelink)

  {

  	int attrtype;
  
  	if (data[IFLA_GENEVE_REMOTE] && data[IFLA_GENEVE_REMOTE6]) {
  		NL_SET_ERR_MSG(extack,
  			       "Cannot specify both IPv4 and IPv6 Remote addresses");

  		return -EINVAL;

  	}

  
  	if (data[IFLA_GENEVE_REMOTE]) {

  		if (changelink && (ip_tunnel_info_af(info) == AF_INET6)) {
  			attrtype = IFLA_GENEVE_REMOTE;
  			goto change_notsup;
  		}

  
  		info->key.u.ipv4.dst =

  			nla_get_in_addr(data[IFLA_GENEVE_REMOTE]);

  		if (ipv4_is_multicast(info->key.u.ipv4.dst)) {

  			NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE],
  					    "Remote IPv4 address cannot be Multicast");

  			return -EINVAL;
  		}

  	}
  
  	if (data[IFLA_GENEVE_REMOTE6]) {

  #if IS_ENABLED(CONFIG_IPV6)

  		if (changelink && (ip_tunnel_info_af(info) == AF_INET)) {
  			attrtype = IFLA_GENEVE_REMOTE6;
  			goto change_notsup;
  		}

  
  		info->mode = IP_TUNNEL_INFO_IPV6;
  		info->key.u.ipv6.dst =

  			nla_get_in6_addr(data[IFLA_GENEVE_REMOTE6]);

  		if (ipv6_addr_type(&info->key.u.ipv6.dst) &

  		    IPV6_ADDR_LINKLOCAL) {

  			NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE6],
  					    "Remote IPv6 address cannot be link-local");

  			return -EINVAL;
  		}

  		if (ipv6_addr_is_multicast(&info->key.u.ipv6.dst)) {

  			NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE6],
  					    "Remote IPv6 address cannot be Multicast");

  			return -EINVAL;
  		}

  		info->key.tun_flags |= TUNNEL_CSUM;
  		*use_udp6_rx_checksums = true;

  #else

  		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE6],
  				    "IPv6 support not enabled in the kernel");

  		return -EPFNOSUPPORT;
  #endif

  	}

  	if (data[IFLA_GENEVE_ID]) {
  		__u32 vni;
  		__u8 tvni[3];

  		__be64 tunid;

  		vni = nla_get_u32(data[IFLA_GENEVE_ID]);

  		tvni[0] = (vni & 0x00ff0000) >> 16;
  		tvni[1] = (vni & 0x0000ff00) >> 8;
  		tvni[2] =  vni & 0x000000ff;

  		tunid = vni_to_tunnel_id(tvni);

  		if (changelink && (tunid != info->key.tun_id)) {
  			attrtype = IFLA_GENEVE_ID;
  			goto change_notsup;
  		}

  		info->key.tun_id = tunid;

  	}

  	if (data[IFLA_GENEVE_TTL_INHERIT]) {
  		if (nla_get_u8(data[IFLA_GENEVE_TTL_INHERIT]))
  			*ttl_inherit = true;
  		else
  			*ttl_inherit = false;
  	} else if (data[IFLA_GENEVE_TTL]) {

  		info->key.ttl = nla_get_u8(data[IFLA_GENEVE_TTL]);

  		*ttl_inherit = false;
  	}

  	if (data[IFLA_GENEVE_TOS])

  		info->key.tos = nla_get_u8(data[IFLA_GENEVE_TOS]);

  	if (data[IFLA_GENEVE_DF])
  		*df = nla_get_u8(data[IFLA_GENEVE_DF]);

  	if (data[IFLA_GENEVE_LABEL]) {

  		info->key.label = nla_get_be32(data[IFLA_GENEVE_LABEL]) &

  				  IPV6_FLOWLABEL_MASK;

  		if (info->key.label && (!(info->mode & IP_TUNNEL_INFO_IPV6))) {
  			NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_LABEL],
  					    "Label attribute only applies for IPv6 Geneve devices");

  			return -EINVAL;

  		}

  	}

  	if (data[IFLA_GENEVE_PORT]) {

  		if (changelink) {
  			attrtype = IFLA_GENEVE_PORT;
  			goto change_notsup;
  		}

  		info->key.tp_dst = nla_get_be16(data[IFLA_GENEVE_PORT]);
  	}

  	if (data[IFLA_GENEVE_COLLECT_METADATA]) {

  		if (changelink) {
  			attrtype = IFLA_GENEVE_COLLECT_METADATA;
  			goto change_notsup;
  		}

  		*metadata = true;
  	}

  	if (data[IFLA_GENEVE_UDP_CSUM]) {

  		if (changelink) {
  			attrtype = IFLA_GENEVE_UDP_CSUM;
  			goto change_notsup;
  		}

  		if (nla_get_u8(data[IFLA_GENEVE_UDP_CSUM]))
  			info->key.tun_flags |= TUNNEL_CSUM;
  	}

  	if (data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]) {

  #if IS_ENABLED(CONFIG_IPV6)

  		if (changelink) {
  			attrtype = IFLA_GENEVE_UDP_ZERO_CSUM6_TX;
  			goto change_notsup;
  		}

  		if (nla_get_u8(data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]))
  			info->key.tun_flags &= ~TUNNEL_CSUM;

  #else
  		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX],
  				    "IPv6 support not enabled in the kernel");
  		return -EPFNOSUPPORT;
  #endif

  	}

  	if (data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX]) {

  #if IS_ENABLED(CONFIG_IPV6)

  		if (changelink) {
  			attrtype = IFLA_GENEVE_UDP_ZERO_CSUM6_RX;
  			goto change_notsup;
  		}

  		if (nla_get_u8(data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX]))
  			*use_udp6_rx_checksums = false;

  #else
  		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX],
  				    "IPv6 support not enabled in the kernel");
  		return -EPFNOSUPPORT;
  #endif

  	}
  
  	return 0;

  change_notsup:
  	NL_SET_ERR_MSG_ATTR(extack, data[attrtype],
  			    "Changing VNI, Port, endpoint IP address family, external, and UDP checksum attributes are not supported");
  	return -EOPNOTSUPP;

  }

  static void geneve_link_config(struct net_device *dev,
  			       struct ip_tunnel_info *info, struct nlattr *tb[])
  {
  	struct geneve_dev *geneve = netdev_priv(dev);
  	int ldev_mtu = 0;
  
  	if (tb[IFLA_MTU]) {
  		geneve_change_mtu(dev, nla_get_u32(tb[IFLA_MTU]));
  		return;
  	}
  
  	switch (ip_tunnel_info_af(info)) {
  	case AF_INET: {
  		struct flowi4 fl4 = { .daddr = info->key.u.ipv4.dst };
  		struct rtable *rt = ip_route_output_key(geneve->net, &fl4);
  
  		if (!IS_ERR(rt) && rt->dst.dev) {
  			ldev_mtu = rt->dst.dev->mtu - GENEVE_IPV4_HLEN;
  			ip_rt_put(rt);
  		}
  		break;
  	}
  #if IS_ENABLED(CONFIG_IPV6)
  	case AF_INET6: {

  		struct rt6_info *rt;
  
  		if (!__in6_dev_get(dev))
  			break;
  
  		rt = rt6_lookup(geneve->net, &info->key.u.ipv6.dst, NULL, 0,
  				NULL, 0);

  
  		if (rt && rt->dst.dev)
  			ldev_mtu = rt->dst.dev->mtu - GENEVE_IPV6_HLEN;
  		ip6_rt_put(rt);
  		break;
  	}
  #endif
  	}
  
  	if (ldev_mtu <= 0)
  		return;
  
  	geneve_change_mtu(dev, ldev_mtu - info->options_len);
  }

  static int geneve_newlink(struct net *net, struct net_device *dev,
  			  struct nlattr *tb[], struct nlattr *data[],
  			  struct netlink_ext_ack *extack)
  {

  	enum ifla_geneve_df df = GENEVE_DF_UNSET;

  	bool use_udp6_rx_checksums = false;
  	struct ip_tunnel_info info;

  	bool ttl_inherit = false;

  	bool metadata = false;
  	int err;
  
  	init_tnl_info(&info, GENEVE_UDP_PORT);

  	err = geneve_nl2info(tb, data, extack, &info, &metadata,

  			     &use_udp6_rx_checksums, &ttl_inherit, &df, false);