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

  #ifndef __NET_VXLAN_H
  #define __NET_VXLAN_H 1

  #include <linux/if_vlan.h>

  #include <net/udp_tunnel.h>

  #include <net/dst_metadata.h>

  #include <net/rtnetlink.h>

  #include <net/switchdev.h>

  #include <net/nexthop.h>

  #define IANA_VXLAN_UDP_PORT     4789

  /* VXLAN protocol (RFC 7348) header:
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |R|R|R|R|I|R|R|R|               Reserved                        |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                VXLAN Network Identifier (VNI) |   Reserved    |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   * I = VXLAN Network Identifier (VNI) present.
   */
  struct vxlanhdr {
  	__be32 vx_flags;
  	__be32 vx_vni;
  };
  
  /* VXLAN header flags. */

  #define VXLAN_HF_VNI	cpu_to_be32(BIT(27))

  
  #define VXLAN_N_VID     (1u << 24)
  #define VXLAN_VID_MASK  (VXLAN_N_VID - 1)

  #define VXLAN_VNI_MASK	cpu_to_be32(VXLAN_VID_MASK << 8)

  #define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))
  
  #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)
  
  /* Remote checksum offload for VXLAN (VXLAN_F_REMCSUM_[RT]X):
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |R|R|R|R|I|R|R|R|R|R|C|              Reserved                   |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |           VXLAN Network Identifier (VNI)      |O| Csum start  |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   * C = Remote checksum offload bit. When set indicates that the
   *     remote checksum offload data is present.
   *
   * O = Offset bit. Indicates the checksum offset relative to
   *     checksum start.
   *
   * Csum start = Checksum start divided by two.
   *
   * http://tools.ietf.org/html/draft-herbert-vxlan-rco
   */
  
  /* VXLAN-RCO header flags. */

  #define VXLAN_HF_RCO	cpu_to_be32(BIT(21))

  
  /* Remote checksum offload header option */

  #define VXLAN_RCO_MASK	cpu_to_be32(0x7f)  /* Last byte of vni field */
  #define VXLAN_RCO_UDP	cpu_to_be32(0x80)  /* Indicate UDP RCO (TCP when not set *) */
  #define VXLAN_RCO_SHIFT	1		   /* Left shift of start */

  #define VXLAN_RCO_SHIFT_MASK ((1 << VXLAN_RCO_SHIFT) - 1)

  #define VXLAN_MAX_REMCSUM_START (0x7f << VXLAN_RCO_SHIFT)

  /*

   * VXLAN Group Based Policy Extension (VXLAN_F_GBP):

   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   * |G|R|R|R|I|R|R|R|R|D|R|R|A|R|R|R|        Group Policy ID        |

   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                VXLAN Network Identifier (VNI) |   Reserved    |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *

   * G = Group Policy ID present.
   *

   * D = Don't Learn bit. When set, this bit indicates that the egress
   *     VTEP MUST NOT learn the source address of the encapsulated frame.
   *
   * A = Indicates that the group policy has already been applied to
   *     this packet. Policies MUST NOT be applied by devices when the
   *     A bit is set.
   *

   * https://tools.ietf.org/html/draft-smith-vxlan-group-policy

   */
  struct vxlanhdr_gbp {

  	u8	vx_flags;

  #ifdef __LITTLE_ENDIAN_BITFIELD

  	u8	reserved_flags1:3,

  		policy_applied:1,
  		reserved_flags2:2,
  		dont_learn:1,
  		reserved_flags3:1;
  #elif defined(__BIG_ENDIAN_BITFIELD)

  	u8	reserved_flags1:1,

  		dont_learn:1,
  		reserved_flags2:2,
  		policy_applied:1,
  		reserved_flags3:3;
  #else
  #error	"Please fix <asm/byteorder.h>"
  #endif
  	__be16	policy_id;
  	__be32	vx_vni;
  };

  /* VXLAN-GBP header flags. */

  #define VXLAN_HF_GBP	cpu_to_be32(BIT(31))

  #define VXLAN_GBP_USED_BITS (VXLAN_HF_GBP | cpu_to_be32(0xFFFFFF))

  
  /* skb->mark mapping
   *
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |R|R|R|R|R|R|R|R|R|D|R|R|A|R|R|R|        Group Policy ID        |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   */
  #define VXLAN_GBP_DONT_LEARN		(BIT(6) << 16)
  #define VXLAN_GBP_POLICY_APPLIED	(BIT(3) << 16)
  #define VXLAN_GBP_ID_MASK		(0xFFFF)

  #define VXLAN_GBP_MASK (VXLAN_GBP_DONT_LEARN | VXLAN_GBP_POLICY_APPLIED | \
  			VXLAN_GBP_ID_MASK)

  /*
   * VXLAN Generic Protocol Extension (VXLAN_F_GPE):
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |R|R|Ver|I|P|R|O|       Reserved                |Next Protocol  |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                VXLAN Network Identifier (VNI) |   Reserved    |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   * Ver = Version. Indicates VXLAN GPE protocol version.
   *
   * P = Next Protocol Bit. The P bit is set to indicate that the
   *     Next Protocol field is present.
   *
   * O = OAM Flag Bit. The O bit is set to indicate that the packet
   *     is an OAM packet.
   *
   * Next Protocol = This 8 bit field indicates the protocol header
   * immediately following the VXLAN GPE header.
   *
   * https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-01
   */
  
  struct vxlanhdr_gpe {
  #if defined(__LITTLE_ENDIAN_BITFIELD)
  	u8	oam_flag:1,
  		reserved_flags1:1,
  		np_applied:1,
  		instance_applied:1,
  		version:2,

  		reserved_flags2:2;

  #elif defined(__BIG_ENDIAN_BITFIELD)
  	u8	reserved_flags2:2,
  		version:2,
  		instance_applied:1,
  		np_applied:1,
  		reserved_flags1:1,
  		oam_flag:1;
  #endif
  	u8	reserved_flags3;
  	u8	reserved_flags4;
  	u8	next_protocol;
  	__be32	vx_vni;
  };
  
  /* VXLAN-GPE header flags. */
  #define VXLAN_HF_VER	cpu_to_be32(BIT(29) | BIT(28))
  #define VXLAN_HF_NP	cpu_to_be32(BIT(26))
  #define VXLAN_HF_OAM	cpu_to_be32(BIT(24))
  
  #define VXLAN_GPE_USED_BITS (VXLAN_HF_VER | VXLAN_HF_NP | VXLAN_HF_OAM | \
  			     cpu_to_be32(0xff))

  struct vxlan_metadata {

  	u32		gbp;
  };

  /* per UDP socket information */
  struct vxlan_sock {
  	struct hlist_node hlist;

  	struct socket	 *sock;

  	struct hlist_head vni_list[VNI_HASH_SIZE];

  	refcount_t	  refcnt;

  	u32		  flags;

  };

  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;

  	u8			 offloaded:1;

  	__be32			 remote_vni;

  	u32			 remote_ifindex;

  	struct net_device	 *remote_dev;

  	struct list_head	 list;
  	struct rcu_head		 rcu;

  	struct dst_cache	 dst_cache;

  };
  
  struct vxlan_config {
  	union vxlan_addr	remote_ip;
  	union vxlan_addr	saddr;

  	__be32			vni;

  	int			remote_ifindex;
  	int			mtu;
  	__be16			dst_port;

  	u16			port_min;
  	u16			port_max;
  	u8			tos;
  	u8			ttl;

  	__be32			label;

  	u32			flags;
  	unsigned long		age_interval;
  	unsigned int		addrmax;
  	bool			no_share;

  	enum ifla_vxlan_df	df;

  };

  struct vxlan_dev_node {
  	struct hlist_node hlist;
  	struct vxlan_dev *vxlan;
  };

  /* Pseudo network device */
  struct vxlan_dev {

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

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

  	struct vxlan_sock __rcu *vn4_sock;	/* listening socket for IPv4 */

  #if IS_ENABLED(CONFIG_IPV6)

  	struct vxlan_sock __rcu *vn6_sock;	/* listening socket for IPv6 */

  #endif

  	struct net_device *dev;
  	struct net	  *net;		/* netns for packet i/o */
  	struct vxlan_rdst default_dst;	/* default destination */

  
  	struct timer_list age_timer;

  	spinlock_t	  hash_lock[FDB_HASH_SIZE];

  	unsigned int	  addrcnt;

  	struct gro_cells  gro_cells;

  
  	struct vxlan_config	cfg;
  
  	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

  #define VXLAN_F_UDP_ZERO_CSUM_TX	0x40

  #define VXLAN_F_UDP_ZERO_CSUM6_TX	0x80
  #define VXLAN_F_UDP_ZERO_CSUM6_RX	0x100

  #define VXLAN_F_REMCSUM_TX		0x200
  #define VXLAN_F_REMCSUM_RX		0x400

  #define VXLAN_F_GBP			0x800

  #define VXLAN_F_REMCSUM_NOPARTIAL	0x1000

  #define VXLAN_F_COLLECT_METADATA	0x2000

  #define VXLAN_F_GPE			0x4000

  #define VXLAN_F_IPV6_LINKLOCAL		0x8000

  #define VXLAN_F_TTL_INHERIT		0x10000

  /* Flags that are used in the receive path. These flags must match in

   * order for a socket to be shareable
   */
  #define VXLAN_F_RCV_FLAGS		(VXLAN_F_GBP |			\

  					 VXLAN_F_GPE |			\

  					 VXLAN_F_UDP_ZERO_CSUM6_RX |	\

  					 VXLAN_F_REMCSUM_RX |		\

  					 VXLAN_F_REMCSUM_NOPARTIAL |	\

  					 VXLAN_F_COLLECT_METADATA)

  /* Flags that can be set together with VXLAN_F_GPE. */
  #define VXLAN_F_ALLOWED_GPE		(VXLAN_F_GPE |			\
  					 VXLAN_F_IPV6 |			\

  					 VXLAN_F_IPV6_LINKLOCAL |	\

  					 VXLAN_F_UDP_ZERO_CSUM_TX |	\
  					 VXLAN_F_UDP_ZERO_CSUM6_TX |	\
  					 VXLAN_F_UDP_ZERO_CSUM6_RX |	\
  					 VXLAN_F_COLLECT_METADATA)

  struct net_device *vxlan_dev_create(struct net *net, const char *name,
  				    u8 name_assign_type, struct vxlan_config *conf);

  static inline netdev_features_t vxlan_features_check(struct sk_buff *skb,
  						     netdev_features_t features)

  {

  	u8 l4_hdr = 0;
  
  	if (!skb->encapsulation)
  		return features;
  
  	switch (vlan_get_protocol(skb)) {
  	case htons(ETH_P_IP):
  		l4_hdr = ip_hdr(skb)->protocol;
  		break;
  	case htons(ETH_P_IPV6):
  		l4_hdr = ipv6_hdr(skb)->nexthdr;
  		break;
  	default:

  		return features;

  	}
  
  	if ((l4_hdr == IPPROTO_UDP) &&

  	    (skb->inner_protocol_type != ENCAP_TYPE_ETHER ||
  	     skb->inner_protocol != htons(ETH_P_TEB) ||
  	     (skb_inner_mac_header(skb) - skb_transport_header(skb) !=

  	      sizeof(struct udphdr) + sizeof(struct vxlanhdr)) ||
  	     (skb->ip_summed != CHECKSUM_NONE &&
  	      !can_checksum_protocol(features, inner_eth_hdr(skb)->h_proto))))

  		return features & ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);

  	return features;

  }

  /* 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)

  static inline struct vxlanhdr *vxlan_hdr(struct sk_buff *skb)
  {
  	return (struct vxlanhdr *)(udp_hdr(skb) + 1);
  }

  static inline __be32 vxlan_vni(__be32 vni_field)
  {
  #if defined(__BIG_ENDIAN)

  	return (__force __be32)((__force u32)vni_field >> 8);

  #else

  	return (__force __be32)((__force u32)(vni_field & VXLAN_VNI_MASK) << 8);

  #endif
  }
  
  static inline __be32 vxlan_vni_field(__be32 vni)
  {
  #if defined(__BIG_ENDIAN)

  	return (__force __be32)((__force u32)vni << 8);

  #else

  	return (__force __be32)((__force u32)vni >> 8);

  #endif
  }

  static inline size_t vxlan_rco_start(__be32 vni_field)
  {
  	return be32_to_cpu(vni_field & VXLAN_RCO_MASK) << VXLAN_RCO_SHIFT;
  }
  
  static inline size_t vxlan_rco_offset(__be32 vni_field)
  {
  	return (vni_field & VXLAN_RCO_UDP) ?
  		offsetof(struct udphdr, check) :
  		offsetof(struct tcphdr, check);
  }
  
  static inline __be32 vxlan_compute_rco(unsigned int start, unsigned int offset)
  {
  	__be32 vni_field = cpu_to_be32(start >> VXLAN_RCO_SHIFT);
  
  	if (offset == offsetof(struct udphdr, check))
  		vni_field |= VXLAN_RCO_UDP;
  	return vni_field;
  }

  static inline unsigned short vxlan_get_sk_family(struct vxlan_sock *vs)
  {
  	return vs->sock->sk->sk_family;
  }

  #if IS_ENABLED(CONFIG_IPV6)
  
  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 ipv4_is_multicast(ipa->sin.sin_addr.s_addr);

  }
  
  #else /* !IS_ENABLED(CONFIG_IPV6) */
  
  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 ipv4_is_multicast(ipa->sin.sin_addr.s_addr);

  }
  
  #endif /* IS_ENABLED(CONFIG_IPV6) */

  static inline bool netif_is_vxlan(const struct net_device *dev)
  {
  	return dev->rtnl_link_ops &&
  	       !strcmp(dev->rtnl_link_ops->kind, "vxlan");
  }

  struct switchdev_notifier_vxlan_fdb_info {
  	struct switchdev_notifier_info info; /* must be first */
  	union vxlan_addr remote_ip;
  	__be16 remote_port;
  	__be32 remote_vni;
  	u32 remote_ifindex;
  	u8 eth_addr[ETH_ALEN];
  	__be32 vni;

  	bool offloaded;

  	bool added_by_user;

  };

  #if IS_ENABLED(CONFIG_VXLAN)
  int vxlan_fdb_find_uc(struct net_device *dev, const u8 *mac, __be32 vni,
  		      struct switchdev_notifier_vxlan_fdb_info *fdb_info);

  int vxlan_fdb_replay(const struct net_device *dev, __be32 vni,

  		     struct notifier_block *nb,
  		     struct netlink_ext_ack *extack);

  void vxlan_fdb_clear_offload(const struct net_device *dev, __be32 vni);

  #else
  static inline int
  vxlan_fdb_find_uc(struct net_device *dev, const u8 *mac, __be32 vni,
  		  struct switchdev_notifier_vxlan_fdb_info *fdb_info)
  {
  	return -ENOENT;
  }

  
  static inline int vxlan_fdb_replay(const struct net_device *dev, __be32 vni,

  				   struct notifier_block *nb,
  				   struct netlink_ext_ack *extack)

  {
  	return -EOPNOTSUPP;
  }

  
  static inline void
  vxlan_fdb_clear_offload(const struct net_device *dev, __be32 vni)
  {
  }

  #endif

  static inline void vxlan_flag_attr_error(int attrtype,
  					 struct netlink_ext_ack *extack)
  {
  #define VXLAN_FLAG(flg) \
  	case IFLA_VXLAN_##flg: \
  		NL_SET_ERR_MSG_MOD(extack, \
  				   "cannot change " #flg " flag"); \
  		break
  	switch (attrtype) {
  	VXLAN_FLAG(TTL_INHERIT);
  	VXLAN_FLAG(LEARNING);
  	VXLAN_FLAG(PROXY);
  	VXLAN_FLAG(RSC);
  	VXLAN_FLAG(L2MISS);
  	VXLAN_FLAG(L3MISS);
  	VXLAN_FLAG(COLLECT_METADATA);
  	VXLAN_FLAG(UDP_ZERO_CSUM6_TX);
  	VXLAN_FLAG(UDP_ZERO_CSUM6_RX);
  	VXLAN_FLAG(REMCSUM_TX);
  	VXLAN_FLAG(REMCSUM_RX);
  	VXLAN_FLAG(GBP);
  	VXLAN_FLAG(GPE);
  	VXLAN_FLAG(REMCSUM_NOPARTIAL);
  	default:
  		NL_SET_ERR_MSG_MOD(extack, \
  				   "cannot change flag");
  		break;
  	}
  #undef VXLAN_FLAG
  }

  static inline bool vxlan_fdb_nh_path_select(struct nexthop *nh,
  					    int hash,
  					    struct vxlan_rdst *rdst)
  {
  	struct fib_nh_common *nhc;
  
  	nhc = nexthop_path_fdb_result(nh, hash);
  	if (unlikely(!nhc))
  		return false;
  
  	switch (nhc->nhc_gw_family) {
  	case AF_INET:
  		rdst->remote_ip.sin.sin_addr.s_addr = nhc->nhc_gw.ipv4;
  		rdst->remote_ip.sa.sa_family = AF_INET;
  		break;
  	case AF_INET6:
  		rdst->remote_ip.sin6.sin6_addr = nhc->nhc_gw.ipv6;
  		rdst->remote_ip.sa.sa_family = AF_INET6;
  		break;
  	}
  
  	return true;
  }

  #endif