text: #ifndef __NET_IP_TUNNELS_WRAPPER_H
  #define __NET_IP_TUNNELS_WRAPPER_H 1
  
  #include <linux/version.h>
  
  #ifdef USE_UPSTREAM_TUNNEL
  /* Block all ip_tunnel functions.
   * Only function that do not depend on ip_tunnel structure can
   * be used. Those needs to be explicitly defined in this header file. */
  #include_next <net/ip_tunnels.h>
  
  #ifndef TUNNEL_ERSPAN_OPT
  #define TUNNEL_ERSPAN_OPT	__cpu_to_be16(0x4000)
  #endif
  #define ovs_ip_tunnel_encap ip_tunnel_encap
  #else
  
  #include <linux/if_tunnel.h>
  #include <linux/types.h>
  #include <net/dsfield.h>
  #include <net/dst_cache.h>
  #include <net/flow.h>
  #include <net/inet_ecn.h>
  #include <net/ip.h>
  #include <net/rtnetlink.h>
  #include <net/gro_cells.h>
  
  #ifndef MAX_IPTUN_ENCAP_OPS
  #define MAX_IPTUN_ENCAP_OPS 8
  #endif
  
  #ifndef HAVE_TUNNEL_ENCAP_TYPES
  enum tunnel_encap_types {
  	TUNNEL_ENCAP_NONE,
  	TUNNEL_ENCAP_FOU,
  	TUNNEL_ENCAP_GUE,
  };
  
  #define HAVE_TUNNEL_ENCAP_TYPES 1
  #endif
  
  #define __iptunnel_pull_header rpl___iptunnel_pull_header
  int rpl___iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
  			   __be16 inner_proto, bool raw_proto, bool xnet);
  
  #define iptunnel_pull_header rpl_iptunnel_pull_header
  static inline int rpl_iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
  				       __be16 inner_proto, bool xnet)
  {
  	return rpl___iptunnel_pull_header(skb, hdr_len, inner_proto, false, xnet);
  }
  
  int ovs_iptunnel_handle_offloads(struct sk_buff *skb,
  				 int gso_type_mask,
  				 void (*fix_segment)(struct sk_buff *));
  
  /* This is required to compile upstream gre.h. gre_handle_offloads()
   * is defined in gre.h and needs iptunnel_handle_offloads(). This provides
   * default signature for this function.
   * rpl prefix is to make OVS build happy.
   */
  #define iptunnel_handle_offloads rpl_iptunnel_handle_offloads
  #if LINUX_VERSION_CODE < KERNEL_VERSION(4,7,0)
  struct sk_buff *rpl_iptunnel_handle_offloads(struct sk_buff *skb,
  					     bool csum_help,
  					     int gso_type_mask);
  #else
  int rpl_iptunnel_handle_offloads(struct sk_buff *skb,
  				 bool csum_help,
  				 int gso_type_mask);
  #endif
  
  #define iptunnel_xmit rpl_iptunnel_xmit
  void rpl_iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
  		       __be32 src, __be32 dst, __u8 proto, __u8 tos, __u8 ttl,
  		       __be16 df, bool xnet);
  #define ip_tunnel_xmit rpl_ip_tunnel_xmit
  void rpl_ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
  			const struct iphdr *tnl_params, const u8 protocol);
  
  
  #ifndef TUNNEL_CSUM
  #define TUNNEL_CSUM		__cpu_to_be16(0x01)
  #define TUNNEL_ROUTING		__cpu_to_be16(0x02)
  #define TUNNEL_KEY		__cpu_to_be16(0x04)
  #define TUNNEL_SEQ		__cpu_to_be16(0x08)
  #define TUNNEL_STRICT		__cpu_to_be16(0x10)
  #define TUNNEL_REC		__cpu_to_be16(0x20)
  #define TUNNEL_VERSION		__cpu_to_be16(0x40)
  #define TUNNEL_NO_KEY		__cpu_to_be16(0x80)
  #define TUNNEL_DONT_FRAGMENT    __cpu_to_be16(0x0100)
  #define TUNNEL_OAM		__cpu_to_be16(0x0200)
  #define TUNNEL_CRIT_OPT		__cpu_to_be16(0x0400)
  #define TUNNEL_GENEVE_OPT	__cpu_to_be16(0x0800)
  #define TUNNEL_VXLAN_OPT	__cpu_to_be16(0x1000)
  #define TUNNEL_NOCACHE		__cpu_to_be16(0x2000)
  #define TUNNEL_ERSPAN_OPT	__cpu_to_be16(0x4000)
  
  #undef TUNNEL_OPTIONS_PRESENT
  #define TUNNEL_OPTIONS_PRESENT \
  		(TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT | TUNNEL_ERSPAN_OPT)
  
  struct tnl_ptk_info {
  	__be16 flags;
  	__be16 proto;
  	__be32 key;
  	__be32 seq;
  	int hdr_len;
  };
  
  #define PACKET_RCVD	0
  #define PACKET_REJECT	1
  #define PACKET_NEXT	2
  #endif
  
  #define IP_TNL_HASH_BITS   7
  #define IP_TNL_HASH_SIZE   (1 << IP_TNL_HASH_BITS)
  
  /* Keep error state on tunnel for 30 sec */
  #define IPTUNNEL_ERR_TIMEO	(30*HZ)
  
  /* Used to memset ip_tunnel padding. */
  #define IP_TUNNEL_KEY_SIZE	offsetofend(struct ip_tunnel_key, tp_dst)
  
  /* Used to memset ipv4 address padding. */
  #define IP_TUNNEL_KEY_IPV4_PAD	offsetofend(struct ip_tunnel_key, u.ipv4.dst)
  #define IP_TUNNEL_KEY_IPV4_PAD_LEN				\
  	(FIELD_SIZEOF(struct ip_tunnel_key, u) -		\
  	 FIELD_SIZEOF(struct ip_tunnel_key, u.ipv4))
  
  struct ip_tunnel_key {
  	__be64			tun_id;
  	union {
  		struct {
  			__be32	src;
  			__be32	dst;
  		} ipv4;
  		struct {
  			struct in6_addr src;
  			struct in6_addr dst;
  		} ipv6;
  	} u;
  	__be16			tun_flags;
  	u8			tos;		/* TOS for IPv4, TC for IPv6 */
  	u8			ttl;		/* TTL for IPv4, HL for IPv6 */
  	__be32                  label;          /* Flow Label for IPv6 */
  	__be16			tp_src;
  	__be16			tp_dst;
  };
  
  /* Flags for ip_tunnel_info mode. */
  #define IP_TUNNEL_INFO_TX	0x01	/* represents tx tunnel parameters */
  #define IP_TUNNEL_INFO_IPV6	0x02	/* key contains IPv6 addresses */
  
  struct ip_tunnel_info {
  	struct ip_tunnel_key	key;
  	struct dst_cache        dst_cache;
  	u8			options_len;
  	u8			mode;
  };
  
  /* 6rd prefix/relay information */
  #ifdef CONFIG_IPV6_SIT_6RD
  struct ip_tunnel_6rd_parm {
  	struct in6_addr		prefix;
  	__be32			relay_prefix;
  	u16			prefixlen;
  	u16			relay_prefixlen;
  };
  #endif
  
  struct ip_tunnel_encap {
  	u16			type;
  	u16			flags;
  	__be16			sport;
  	__be16			dport;
  };
  
  struct ip_tunnel_prl_entry {
  	struct ip_tunnel_prl_entry __rcu *next;
  	__be32				addr;
  	u16				flags;
  	struct rcu_head			rcu_head;
  };
  
  static inline unsigned short ip_tunnel_info_af(const struct ip_tunnel_info *tun_info)
  {
  	return tun_info->mode & IP_TUNNEL_INFO_IPV6 ? AF_INET6 : AF_INET;
  }
  
  static inline void *ip_tunnel_info_opts(struct ip_tunnel_info *info)
  {
  	return info + 1;
  }
  
  static inline void ip_tunnel_info_opts_get(void *to,
  					   const struct ip_tunnel_info *info)
  {
  	memcpy(to, info + 1, info->options_len);
  }
  
  static inline void ip_tunnel_info_opts_set(struct ip_tunnel_info *info,
  					   const void *from, int len)
  {
  	memcpy(ip_tunnel_info_opts(info), from, len);
  	info->options_len = len;
  }
  
  static inline void ip_tunnel_key_init(struct ip_tunnel_key *key,
  				      __be32 saddr, __be32 daddr,
  				      u8 tos, u8 ttl, __be32 label,
  				      __be16 tp_src, __be16 tp_dst,
  				      __be64 tun_id, __be16 tun_flags)
  {
  	key->tun_id = tun_id;
  	key->u.ipv4.src = saddr;
  	key->u.ipv4.dst = daddr;
  	memset((unsigned char *)key + IP_TUNNEL_KEY_IPV4_PAD,
  	       0, IP_TUNNEL_KEY_IPV4_PAD_LEN);
  	key->tos = tos;
  	key->ttl = ttl;
  	key->label = label;
  	key->tun_flags = tun_flags;
  
  	/* For the tunnel types on the top of IPsec, the tp_src and tp_dst of
  	 * the upper tunnel are used.
  	 * E.g: GRE over IPSEC, the tp_src and tp_port are zero.
  	 */
  	key->tp_src = tp_src;
  	key->tp_dst = tp_dst;
  
  	/* Clear struct padding. */
  	if (sizeof(*key) != IP_TUNNEL_KEY_SIZE)
  		memset((unsigned char *)key + IP_TUNNEL_KEY_SIZE,
  		       0, sizeof(*key) - IP_TUNNEL_KEY_SIZE);
  }
  
  #define ip_tunnel_collect_metadata() true
  
  #undef TUNNEL_NOCACHE
  #define TUNNEL_NOCACHE 0
  
  static inline bool
  ip_tunnel_dst_cache_usable(const struct sk_buff *skb,
  			   const struct ip_tunnel_info *info)
  {
  	if (skb->mark)
  		return false;
  	if (!info)
  		return true;
  	if (info->key.tun_flags & TUNNEL_NOCACHE)
  		return false;
  
  	return true;
  }
  
  #define ip_tunnel_dst rpl_ip_tunnel_dst
  struct rpl_ip_tunnel_dst {
  	struct dst_entry __rcu		*dst;
  	__be32				saddr;
  };
  
  #define ip_tunnel rpl_ip_tunnel
  struct rpl_ip_tunnel {
  	struct ip_tunnel __rcu	*next;
  	struct hlist_node hash_node;
  	struct net_device	*dev;
  	struct net		*net;	/* netns for packet i/o */
  
  	unsigned long	err_time;	/* Time when the last ICMP error
  					 * arrived */
  	int		err_count;	/* Number of arrived ICMP errors */
  
  	/* These four fields used only by GRE */
  	u32		i_seqno;	/* The last seen seqno	*/
  	u32		o_seqno;	/* The last output seqno */
  	int		tun_hlen;	/* Precalculated header length */
  
  	/* These four fields used only by ERSPAN */
  	u32		index;		/* ERSPAN type II index */
  	u8		erspan_ver;	/* ERSPAN version */
  	u8		dir;		/* ERSPAN direction */
  	u16		hwid;		/* ERSPAN hardware ID */
  
  	struct dst_cache dst_cache;
  
  	struct ip_tunnel_parm parms;
  
  	int		mlink;
  	int		encap_hlen;	/* Encap header length (FOU,GUE) */
  	int		hlen;		/* tun_hlen + encap_hlen */
  	struct ip_tunnel_encap encap;
  
  	/* for SIT */
  #ifdef CONFIG_IPV6_SIT_6RD
  	struct ip_tunnel_6rd_parm ip6rd;
  #endif
  	struct ip_tunnel_prl_entry __rcu *prl;	/* potential router list */
  	unsigned int		prl_count;	/* # of entries in PRL */
  	unsigned int		ip_tnl_net_id;
  	struct gro_cells	gro_cells;
  	__u32			fwmark;
  	bool			collect_md;
  	bool			ignore_df;
  };
  
  #define ip_tunnel_net rpl_ip_tunnel_net
  struct rpl_ip_tunnel_net {
  	struct net_device *fb_tunnel_dev;
  	struct hlist_head tunnels[IP_TNL_HASH_SIZE];
  	struct ip_tunnel __rcu *collect_md_tun;
  };
  
  
  struct ip_tunnel_encap_ops {
  	size_t (*encap_hlen)(struct ip_tunnel_encap *e);
  	int (*build_header)(struct sk_buff *skb, struct ip_tunnel_encap *e,
  			    const u8 *protocol, struct flowi4 *fl4);
  };
  
  extern const struct ip_tunnel_encap_ops __rcu *
  		rpl_iptun_encaps[MAX_IPTUN_ENCAP_OPS];
  
  #define ip_encap_hlen rpl_ip_encap_hlen
  static inline int rpl_ip_encap_hlen(struct ip_tunnel_encap *e)
  {
  	const struct ip_tunnel_encap_ops *ops;
  	int hlen = -EINVAL;
  
  	if (e->type == TUNNEL_ENCAP_NONE)
  		return 0;
  
  	if (e->type >= MAX_IPTUN_ENCAP_OPS)
  		return -EINVAL;
  
  	rcu_read_lock();
  	ops = rcu_dereference(rpl_iptun_encaps[e->type]);
  	if (likely(ops && ops->encap_hlen))
  		hlen = ops->encap_hlen(e);
  	rcu_read_unlock();
  
  	return hlen;
  }
  
  static inline int ovs_ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
  				      const u8 *protocol, struct flowi4 *fl4)
  {
  	const struct ip_tunnel_encap_ops *ops;
  	int ret = -EINVAL;
  
  	if (t->encap.type == TUNNEL_ENCAP_NONE)
  		return 0;
  
  	if (t->encap.type >= MAX_IPTUN_ENCAP_OPS)
  		return -EINVAL;
  
  	rcu_read_lock();
  	ops = rcu_dereference(rpl_iptun_encaps[t->encap.type]);
  	if (likely(ops && ops->build_header))
  		ret = ops->build_header(skb, &t->encap, protocol, fl4);
  	rcu_read_unlock();
  
  	return ret;
  }
  
  #define ip_tunnel_get_stats64 rpl_ip_tunnel_get_stats64
  #if LINUX_VERSION_CODE < KERNEL_VERSION(4,11,0) && !defined(HAVE_RHEL7_MAX_MTU)
  struct rtnl_link_stats64 *rpl_ip_tunnel_get_stats64(struct net_device *dev,
  						    struct rtnl_link_stats64 *tot);
  #else
  void rpl_ip_tunnel_get_stats64(struct net_device *dev,
  						    struct rtnl_link_stats64 *tot);
  #endif
  #define ip_tunnel_get_dsfield rpl_ip_tunnel_get_dsfield
  static inline u8 rpl_ip_tunnel_get_dsfield(const struct iphdr *iph,
  					   const struct sk_buff *skb)
  {
  	if (skb->protocol == htons(ETH_P_IP))
  		return iph->tos;
  	else if (skb->protocol == htons(ETH_P_IPV6))
  		return ipv6_get_dsfield((const struct ipv6hdr *)iph);
  	else
  		return 0;
  }
  
  #define ip_tunnel_ecn_encap rpl_ip_tunnel_ecn_encap
  static inline u8 rpl_ip_tunnel_ecn_encap(u8 tos, const struct iphdr *iph,
  		const struct sk_buff *skb)
  {
  	u8 inner = ip_tunnel_get_dsfield(iph, skb);
  
  	return INET_ECN_encapsulate(tos, inner);
  }
  
  static inline void iptunnel_xmit_stats(struct net_device *dev, int pkt_len)
  {
  	if (pkt_len > 0) {
  		struct pcpu_sw_netstats *tstats = get_cpu_ptr(dev->tstats);
  
  		u64_stats_update_begin(&tstats->syncp);
  		tstats->tx_bytes += pkt_len;
  		tstats->tx_packets++;
  		u64_stats_update_end(&tstats->syncp);
  		put_cpu_ptr(tstats);
  	} else {
  		struct net_device_stats *err_stats = &dev->stats;
  
  		if (pkt_len < 0) {
  			err_stats->tx_errors++;
  			err_stats->tx_aborted_errors++;
  		} else {
  			err_stats->tx_dropped++;
  		}
  	}
  }
  
  static inline __be64 key32_to_tunnel_id(__be32 key)
  {
  #ifdef __BIG_ENDIAN
  	return (__force __be64)key;
  #else
  	return (__force __be64)((__force u64)key << 32);
  #endif
  }
  
  /* Returns the least-significant 32 bits of a __be64. */
  static inline __be32 tunnel_id_to_key32(__be64 tun_id)
  {
  #ifdef __BIG_ENDIAN
  	return (__force __be32)tun_id;
  #else
  	return (__force __be32)((__force u64)tun_id >> 32);
  #endif
  }
  
  #define ip_tunnel_init rpl_ip_tunnel_init
  int rpl_ip_tunnel_init(struct net_device *dev);
  
  #define ip_tunnel_uninit rpl_ip_tunnel_uninit
  void rpl_ip_tunnel_uninit(struct net_device *dev);
  
  #define ip_tunnel_change_mtu rpl_ip_tunnel_change_mtu
  int rpl_ip_tunnel_change_mtu(struct net_device *dev, int new_mtu);
  
  #define ip_tunnel_newlink rpl_ip_tunnel_newlink
  int rpl_ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
  			  struct ip_tunnel_parm *p);
  
  #define ip_tunnel_dellink rpl_ip_tunnel_dellink
  void rpl_ip_tunnel_dellink(struct net_device *dev, struct list_head *head);
  
  #define ip_tunnel_init_net rpl_ip_tunnel_init_net
  int rpl_ip_tunnel_init_net(struct net *net, int ip_tnl_net_id,
  			   struct rtnl_link_ops *ops, char *devname);
  
  #define ip_tunnel_delete_net rpl_ip_tunnel_delete_net
  void rpl_ip_tunnel_delete_net(struct ip_tunnel_net *itn, struct rtnl_link_ops *ops);
  
  #define ip_tunnel_setup rpl_ip_tunnel_setup
  void rpl_ip_tunnel_setup(struct net_device *dev, int net_id);
  
  #define ip_tunnel_get_iflink rpl_ip_tunnel_get_iflink
  int rpl_ip_tunnel_get_iflink(const struct net_device *dev);
  
  #define ip_tunnel_get_link_net rpl_ip_tunnel_get_link_net
  struct net *rpl_ip_tunnel_get_link_net(const struct net_device *dev);
  
  #define __ip_tunnel_change_mtu rpl___ip_tunnel_change_mtu
  int rpl___ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict);
  
  #define ip_tunnel_lookup rpl_ip_tunnel_lookup
  struct ip_tunnel *rpl_ip_tunnel_lookup(struct ip_tunnel_net *itn,
  				       int link, __be16 flags,
  				       __be32 remote, __be32 local,
  				       __be32 key);
  
  static inline int iptunnel_pull_offloads(struct sk_buff *skb)
  {
  	if (skb_is_gso(skb)) {
  		int err;
  
  		err = skb_unclone(skb, GFP_ATOMIC);
  		if (unlikely(err))
  			return err;
  		skb_shinfo(skb)->gso_type &= ~(NETIF_F_GSO_ENCAP_ALL >>
  					       NETIF_F_GSO_SHIFT);
  	}
  
  	skb->encapsulation = 0;
  	return 0;
  }
  #endif /* USE_UPSTREAM_TUNNEL */
  
  #define skb_is_encapsulated ovs_skb_is_encapsulated
  bool ovs_skb_is_encapsulated(struct sk_buff *skb);
  
  #endif /* __NET_IP_TUNNELS_H */
  