/*
   * INET		An implementation of the TCP/IP protocol suite for the LINUX
   *		operating system.  INET is implemented using the  BSD Socket
   *		interface as the means of communication with the user level.
   *
   *		Definitions for the IP module.
   *
   * Version:	@(#)ip.h	1.0.2	05/07/93
   *

   * Authors:	Ross Biro

   *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
   *		Alan Cox, <gw4pts@gw4pts.ampr.org>
   *
   * Changes:
   *		Mike McLagan    :       Routing by source
   *
   *		This program is free software; you can redistribute it and/or
   *		modify it under the terms of the GNU General Public License
   *		as published by the Free Software Foundation; either version
   *		2 of the License, or (at your option) any later version.
   */
  #ifndef _IP_H
  #define _IP_H

  #include <linux/types.h>

  #include <linux/ip.h>
  #include <linux/in.h>

  #include <linux/skbuff.h>

  
  #include <net/inet_sock.h>

  #include <net/route.h>

  #include <net/snmp.h>

  #include <net/flow.h>

  #include <net/flow_dissector.h>

  
  struct sock;

  struct inet_skb_parm {

  	int			iif;

  	struct ip_options	opt;		/* Compiled IP options		*/

  	u16			flags;

  #define IPSKB_FORWARDED		BIT(0)
  #define IPSKB_XFRM_TUNNEL_SIZE	BIT(1)
  #define IPSKB_XFRM_TRANSFORMED	BIT(2)
  #define IPSKB_FRAG_COMPLETE	BIT(3)
  #define IPSKB_REROUTED		BIT(4)
  #define IPSKB_DOREDIRECT	BIT(5)

  #define IPSKB_FRAG_PMTU		BIT(6)

  #define IPSKB_L3SLAVE		BIT(7)

  
  	u16			frag_max_size;

  };

  static inline bool ipv4_l3mdev_skb(u16 flags)
  {
  	return !!(flags & IPSKB_L3SLAVE);
  }

  static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  {

  	return ip_hdr(skb)->ihl * 4;

  }

  struct ipcm_cookie {

  	struct sockcm_cookie	sockc;

  	__be32			addr;

  	int			oif;

  	struct ip_options_rcu	*opt;

  	__u8			tx_flags;

  	__u8			ttl;
  	__s16			tos;
  	char			priority;

  };
  
  #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))

  #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))

  struct ip_ra_chain {

  	struct ip_ra_chain __rcu *next;

  	struct sock		*sk;

  	union {
  		void			(*destructor)(struct sock *);
  		struct sock		*saved_sk;
  	};

  	struct rcu_head		rcu;

  };

  extern struct ip_ra_chain __rcu *ip_ra_chain;

  
  /* IP flags. */
  #define IP_CE		0x8000		/* Flag: "Congestion"		*/
  #define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
  #define IP_MF		0x2000		/* Flag: "More Fragments"	*/
  #define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/
  
  #define IP_FRAG_TIME	(30 * HZ)		/* fragment lifetime	*/

  struct msghdr;
  struct net_device;
  struct packet_type;
  struct rtable;

  struct sockaddr;

  int igmp_mc_init(void);

  
  /*
   *	Functions provided by ip.c
   */

  int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,

  			  __be32 saddr, __be32 daddr,
  			  struct ip_options_rcu *opt);
  int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
  	   struct net_device *orig_dev);
  int ip_local_deliver(struct sk_buff *skb);
  int ip_mr_input(struct sk_buff *skb);

  int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
  int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);

  int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
  		   int (*output)(struct net *, struct sock *, struct sk_buff *));

  void ip_send_check(struct iphdr *ip);

  int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);

  int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);

  int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);

  void ip_init(void);
  int ip_append_data(struct sock *sk, struct flowi4 *fl4,
  		   int getfrag(void *from, char *to, int offset, int len,
  			       int odd, struct sk_buff *skb),
  		   void *from, int len, int protolen,
  		   struct ipcm_cookie *ipc,
  		   struct rtable **rt,
  		   unsigned int flags);
  int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
  		       struct sk_buff *skb);
  ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
  		       int offset, size_t size, int flags);
  struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
  			      struct sk_buff_head *queue,
  			      struct inet_cork *cork);
  int ip_send_skb(struct net *net, struct sk_buff *skb);
  int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
  void ip_flush_pending_frames(struct sock *sk);
  struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
  			    int getfrag(void *from, char *to, int offset,
  					int len, int odd, struct sk_buff *skb),
  			    void *from, int length, int transhdrlen,
  			    struct ipcm_cookie *ipc, struct rtable **rtp,
  			    unsigned int flags);

  static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)

  {

  	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);

  }

  static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
  {
  	return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
  }
  
  static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
  {
  	return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
  }

  /* datagram.c */

  int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);

  int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);

  void ip4_datagram_release_cb(struct sock *sk);

  struct ip_reply_arg {
  	struct kvec iov[1];   

  	int	    flags;

  	__wsum 	    csum;

  	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */
  				/* -1 if not needed */ 

  	int	    bound_dev_if;

  	u8  	    tos;

  }; 

  #define IP_REPLY_ARG_NOSRCCHECK 1

  static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
  {
  	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
  }

  void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,

  			   const struct ip_options *sopt,
  			   __be32 daddr, __be32 saddr,
  			   const struct ip_reply_arg *arg,

  			   unsigned int len);

  #define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)

  #define __IP_INC_STATS(net, field)	__SNMP_INC_STATS64((net)->mib.ip_statistics, field)

  #define IP_ADD_STATS(net, field, val)	SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)

  #define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)

  #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)

  #define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)

  #define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)

  #define __NET_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.net_statistics, field)

  #define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)

  #define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)

  u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);

  unsigned long snmp_fold_field(void __percpu *mib, int offt);

  #if BITS_PER_LONG==32

  u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
  			 size_t syncp_offset);

  u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);

  #else

  static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
  					size_t syncp_offset)
  {
  	return snmp_get_cpu_field(mib, cpu, offct);
  
  }

  static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)

  {
  	return snmp_fold_field(mib, offt);
  }
  #endif

  #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
  { \
  	int i, c; \
  	for_each_possible_cpu(c) { \
  		for (i = 0; stats_list[i].name; i++) \
  			buff64[i] += snmp_get_cpu_field64( \
  					mib_statistic, \
  					c, stats_list[i].entry, \
  					offset); \
  	} \
  }
  
  #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
  { \
  	int i, c; \
  	for_each_possible_cpu(c) { \
  		for (i = 0; stats_list[i].name; i++) \
  			buff[i] += snmp_get_cpu_field( \
  						mib_statistic, \
  						c, stats_list[i].entry); \
  	} \
  }

  void inet_get_local_port_range(struct net *net, int *low, int *high);

  #ifdef CONFIG_SYSCTL

  static inline int inet_is_local_reserved_port(struct net *net, int port)

  {

  	if (!net->ipv4.sysctl_local_reserved_ports)
  		return 0;
  	return test_bit(port, net->ipv4.sysctl_local_reserved_ports);

  }

  
  static inline bool sysctl_dev_name_is_allowed(const char *name)
  {
  	return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
  }

  #else
  static inline int inet_is_local_reserved_port(struct net *net, int port)
  {
  	return 0;
  }
  #endif

  __be32 inet_current_timestamp(void);

  /* From inetpeer.c */
  extern int inet_peer_threshold;
  extern int inet_peer_minttl;
  extern int inet_peer_maxttl;

  void ipfrag_init(void);

  void ip_static_sysctl_init(void);

  #define IP4_REPLY_MARK(net, mark) \
  	((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)

  static inline bool ip_is_fragment(const struct iphdr *iph)
  {
  	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
  }

  #ifdef CONFIG_INET

  #include <net/dst.h>

  /* The function in 2.2 was invalid, producing wrong result for
   * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
  static inline
  int ip_decrease_ttl(struct iphdr *iph)
  {

  	u32 check = (__force u32)iph->check;
  	check += (__force u32)htons(0x0100);
  	iph->check = (__force __sum16)(check + (check>=0xFFFF));

  	return --iph->ttl;
  }
  
  static inline

  int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)

  {

  	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
  
  	return  pmtudisc == IP_PMTUDISC_DO ||
  		(pmtudisc == IP_PMTUDISC_WANT &&

  		 !(dst_metric_locked(dst, RTAX_MTU)));

  }

  static inline bool ip_sk_accept_pmtu(const struct sock *sk)
  {

  	return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
  	       inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;

  }
  
  static inline bool ip_sk_use_pmtu(const struct sock *sk)
  {
  	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
  }

  static inline bool ip_sk_ignore_df(const struct sock *sk)

  {
  	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
  	       inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
  }

  static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
  						    bool forwarding)
  {
  	struct net *net = dev_net(dst->dev);
  
  	if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
  	    dst_metric_locked(dst, RTAX_MTU) ||
  	    !forwarding)
  		return dst_mtu(dst);
  
  	return min(dst->dev->mtu, IP_MAX_MTU);
  }

  static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
  					  const struct sk_buff *skb)

  {

  	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {

  		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;

  		return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);

  	}

  
  	return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);

  }

  u32 ip_idents_reserve(u32 hash, int segs);

  void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);

  static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
  					struct sock *sk, int segs)

  {

  	struct iphdr *iph = ip_hdr(skb);

  	if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {

  		/* This is only to work around buggy Windows95/2000
  		 * VJ compression implementations.  If the ID field
  		 * does not change, they drop every other packet in
  		 * a TCP stream using header compression.
  		 */

  		if (sk && inet_sk(sk)->inet_daddr) {
  			iph->id = htons(inet_sk(sk)->inet_id);

  			inet_sk(sk)->inet_id += segs;
  		} else {

  			iph->id = 0;

  		}
  	} else {

  		__ip_select_ident(net, iph, segs);

  	}
  }

  static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
  				   struct sock *sk)

  {

  	ip_select_ident_segs(net, skb, sk, 1);

  }

  static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
  {
  	return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
  				  skb->len, proto, 0);
  }

  /* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
   * Equivalent to :	flow->v4addrs.src = iph->saddr;
   *			flow->v4addrs.dst = iph->daddr;
   */
  static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
  					    const struct iphdr *iph)
  {
  	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
  		     offsetof(typeof(flow->addrs), v4addrs.src) +
  			      sizeof(flow->addrs.v4addrs.src));
  	memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
  	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
  }

  static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
  {
  	const struct iphdr *iph = skb_gro_network_header(skb);
  
  	return csum_tcpudp_nofold(iph->saddr, iph->daddr,
  				  skb_gro_len(skb), proto, 0);
  }

  /*
   *	Map a multicast IP onto multicast MAC for type ethernet.
   */

  static inline void ip_eth_mc_map(__be32 naddr, char *buf)

  {

  	__u32 addr=ntohl(naddr);

  	buf[0]=0x01;
  	buf[1]=0x00;
  	buf[2]=0x5e;
  	buf[5]=addr&0xFF;
  	addr>>=8;
  	buf[4]=addr&0xFF;
  	addr>>=8;
  	buf[3]=addr&0x7F;
  }
  
  /*
   *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
   *	Leave P_Key as 0 to be filled in by driver.
   */

  static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)

  {

  	__u32 addr;

  	unsigned char scope = broadcast[5] & 0xF;

  	buf[0]  = 0;		/* Reserved */
  	buf[1]  = 0xff;		/* Multicast QPN */
  	buf[2]  = 0xff;
  	buf[3]  = 0xff;

  	addr    = ntohl(naddr);

  	buf[4]  = 0xff;

  	buf[5]  = 0x10 | scope;	/* scope from broadcast address */

  	buf[6]  = 0x40;		/* IPv4 signature */
  	buf[7]  = 0x1b;

  	buf[8]  = broadcast[8];		/* P_Key */
  	buf[9]  = broadcast[9];

  	buf[10] = 0;
  	buf[11] = 0;
  	buf[12] = 0;
  	buf[13] = 0;
  	buf[14] = 0;
  	buf[15] = 0;
  	buf[19] = addr & 0xff;
  	addr  >>= 8;
  	buf[18] = addr & 0xff;
  	addr  >>= 8;
  	buf[17] = addr & 0xff;
  	addr  >>= 8;
  	buf[16] = addr & 0x0f;
  }

  static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
  {
  	if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
  		memcpy(buf, broadcast, 4);
  	else
  		memcpy(buf, &naddr, sizeof(naddr));
  }

  #if IS_ENABLED(CONFIG_IPV6)

  #include <linux/ipv6.h>
  #endif
  
  static __inline__ void inet_reset_saddr(struct sock *sk)
  {

  	inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;

  #if IS_ENABLED(CONFIG_IPV6)

  	if (sk->sk_family == PF_INET6) {
  		struct ipv6_pinfo *np = inet6_sk(sk);
  
  		memset(&np->saddr, 0, sizeof(np->saddr));

  		memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));

  	}
  #endif
  }
  
  #endif

  static inline unsigned int ipv4_addr_hash(__be32 ip)
  {
  	return (__force unsigned int) ip;
  }

  bool ip_call_ra_chain(struct sk_buff *skb);

  
  /*

   *	Functions provided by ip_fragment.c

   */

  enum ip_defrag_users {

  	IP_DEFRAG_LOCAL_DELIVER,
  	IP_DEFRAG_CALL_RA_CHAIN,
  	IP_DEFRAG_CONNTRACK_IN,

  	__IP_DEFRAG_CONNTRACK_IN_END	= IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,

  	IP_DEFRAG_CONNTRACK_OUT,

  	__IP_DEFRAG_CONNTRACK_OUT_END	= IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,

  	IP_DEFRAG_CONNTRACK_BRIDGE_IN,

  	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,

  	IP_DEFRAG_VS_IN,
  	IP_DEFRAG_VS_OUT,

  	IP_DEFRAG_VS_FWD,
  	IP_DEFRAG_AF_PACKET,

  	IP_DEFRAG_MACVLAN,

  };

  /* Return true if the value of 'user' is between 'lower_bond'
   * and 'upper_bond' inclusively.
   */
  static inline bool ip_defrag_user_in_between(u32 user,
  					     enum ip_defrag_users lower_bond,
  					     enum ip_defrag_users upper_bond)
  {
  	return user >= lower_bond && user <= upper_bond;
  }

  int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);

  #ifdef CONFIG_INET

  struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);

  #else

  static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)

  {
  	return skb;
  }
  #endif

  int ip_frag_mem(struct net *net);

  
  /*
   *	Functions provided by ip_forward.c
   */
   

  int ip_forward(struct sk_buff *skb);

   
  /*
   *	Functions provided by ip_options.c
   */
   

  void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
  		      __be32 daddr, struct rtable *rt, int is_frag);

  
  int __ip_options_echo(struct ip_options *dopt, struct sk_buff *skb,
  		      const struct ip_options *sopt);
  static inline int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb)
  {
  	return __ip_options_echo(dopt, skb, &IPCB(skb)->opt);
  }

  void ip_options_fragment(struct sk_buff *skb);
  int ip_options_compile(struct net *net, struct ip_options *opt,
  		       struct sk_buff *skb);
  int ip_options_get(struct net *net, struct ip_options_rcu **optp,
  		   unsigned char *data, int optlen);
  int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
  			     unsigned char __user *data, int optlen);
  void ip_options_undo(struct ip_options *opt);
  void ip_forward_options(struct sk_buff *skb);
  int ip_options_rcv_srr(struct sk_buff *skb);

  
  /*
   *	Functions provided by ip_sockglue.c
   */

  void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);

  void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb, int tlen, int offset);

  int ip_cmsg_send(struct sock *sk, struct msghdr *msg,

  		 struct ipcm_cookie *ipc, bool allow_ipv6);

  int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
  		  unsigned int optlen);
  int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
  		  int __user *optlen);
  int compat_ip_setsockopt(struct sock *sk, int level, int optname,
  			 char __user *optval, unsigned int optlen);
  int compat_ip_getsockopt(struct sock *sk, int level, int optname,
  			 char __user *optval, int __user *optlen);
  int ip_ra_control(struct sock *sk, unsigned char on,
  		  void (*destructor)(struct sock *));

  int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);

  void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
  		   u32 info, u8 *payload);
  void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
  		    u32 info);

  static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
  {

  	ip_cmsg_recv_offset(msg, skb, 0, 0);

  }

  bool icmp_global_allow(void);
  extern int sysctl_icmp_msgs_per_sec;
  extern int sysctl_icmp_msgs_burst;

  #ifdef CONFIG_PROC_FS

  int ip_misc_proc_init(void);

  #endif

  #endif	/* _IP_H */