text: /*
   * 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 router.
   *
   * Version:	@(#)route.h	1.0.4	05/27/93
   *
   * Authors:	Ross Biro
   *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
   * Fixes:
   *		Alan Cox	:	Reformatted. Added ip_rt_local()
   *		Alan Cox	:	Support for TCP parameters.
   *		Alexey Kuznetsov:	Major changes for new routing code.
   *		Mike McLagan    :	Routing by source
   *		Robert Olsson   :	Added rt_cache statistics
   *
   *		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 _ROUTE_H
  #define _ROUTE_H
  
  #include <net/dst.h>
  #include <net/inetpeer.h>
  #include <net/flow.h>
  #include <net/inet_sock.h>
  #include <linux/in_route.h>
  #include <linux/rtnetlink.h>
  #include <linux/route.h>
  #include <linux/ip.h>
  #include <linux/cache.h>
  #include <linux/security.h>
  
  #ifndef __KERNEL__
  #warning This file is not supposed to be used outside of kernel.
  #endif
  
  #define RTO_ONLINK	0x01
  
  #define RTO_CONN	0
  /* RTO_CONN is not used (being alias for 0), but preserved not to break
   * some modules referring to it. */
  
  #define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
  
  struct fib_nh;
  struct inet_peer;
  struct rtable {
  	struct dst_entry	dst;
  
  	/* Cache lookup keys */
  	struct flowi		fl;
  
  	struct in_device	*idev;
  	
  	int			rt_genid;
  	unsigned		rt_flags;
  	__u16			rt_type;
  
  	__be32			rt_dst;	/* Path destination	*/
  	__be32			rt_src;	/* Path source		*/
  	int			rt_iif;
  
  	/* Info on neighbour */
  	__be32			rt_gateway;
  
  	/* Miscellaneous cached information */
  	__be32			rt_spec_dst; /* RFC1122 specific destination */
  	struct inet_peer	*peer; /* long-living peer info */
  };
  
  struct ip_rt_acct {
  	__u32 	o_bytes;
  	__u32 	o_packets;
  	__u32 	i_bytes;
  	__u32 	i_packets;
  };
  
  struct rt_cache_stat {
          unsigned int in_hit;
          unsigned int in_slow_tot;
          unsigned int in_slow_mc;
          unsigned int in_no_route;
          unsigned int in_brd;
          unsigned int in_martian_dst;
          unsigned int in_martian_src;
          unsigned int out_hit;
          unsigned int out_slow_tot;
          unsigned int out_slow_mc;
          unsigned int gc_total;
          unsigned int gc_ignored;
          unsigned int gc_goal_miss;
          unsigned int gc_dst_overflow;
          unsigned int in_hlist_search;
          unsigned int out_hlist_search;
  };
  
  extern struct ip_rt_acct __percpu *ip_rt_acct;
  
  struct in_device;
  extern int		ip_rt_init(void);
  extern void		ip_rt_redirect(__be32 old_gw, __be32 dst, __be32 new_gw,
  				       __be32 src, struct net_device *dev);
  extern void		rt_cache_flush(struct net *net, int how);
  extern void		rt_cache_flush_batch(void);
  extern int		__ip_route_output_key(struct net *, struct rtable **, const struct flowi *flp);
  extern int		ip_route_output_key(struct net *, struct rtable **, struct flowi *flp);
  extern int		ip_route_output_flow(struct net *, struct rtable **rp, struct flowi *flp, struct sock *sk, int flags);
  
  extern int ip_route_input_common(struct sk_buff *skb, __be32 dst, __be32 src,
  				 u8 tos, struct net_device *devin, bool noref);
  
  static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
  				 u8 tos, struct net_device *devin)
  {
  	return ip_route_input_common(skb, dst, src, tos, devin, false);
  }
  
  static inline int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
  				       u8 tos, struct net_device *devin)
  {
  	return ip_route_input_common(skb, dst, src, tos, devin, true);
  }
  
  extern int		ip_route_input_lookup(struct sk_buff*, __be32 dst, __be32 src, u8 tos, struct net_device *devin, __be32 lsrc);
  extern unsigned short	ip_rt_frag_needed(struct net *net, struct iphdr *iph, unsigned short new_mtu, struct net_device *dev);
  extern void		ip_rt_send_redirect(struct sk_buff *skb);
  
  extern unsigned		inet_addr_type(struct net *net, __be32 addr);
  extern unsigned		inet_dev_addr_type(struct net *net, const struct net_device *dev, __be32 addr);
  extern void		ip_rt_multicast_event(struct in_device *);
  extern int		ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
  extern void		ip_rt_get_source(u8 *src, struct rtable *rt);
  extern int		ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb);
  
  struct in_ifaddr;
  extern void fib_add_ifaddr(struct in_ifaddr *);
  
  static inline void ip_rt_put(struct rtable * rt)
  {
  	if (rt)
  		dst_release(&rt->dst);
  }
  
  #define IPTOS_RT_MASK	(IPTOS_TOS_MASK & ~3)
  
  extern const __u8 ip_tos2prio[16];
  
  static inline char rt_tos2priority(u8 tos)
  {
  	return ip_tos2prio[IPTOS_TOS(tos)>>1];
  }
  
  static inline int ip_route_connect(struct rtable **rp, __be32 dst,
  				   __be32 src, u32 tos, int oif, u8 protocol,
  				   __be16 sport, __be16 dport, struct sock *sk,
  				   int flags)
  {
  	struct flowi fl = { .oif = oif,
  			    .mark = sk->sk_mark,
  			    .nl_u = { .ip4_u = { .daddr = dst,
  						 .saddr = src,
  						 .tos   = tos } },
  			    .proto = protocol,
  			    .uli_u = { .ports =
  				       { .sport = sport,
  					 .dport = dport } } };
  
  	int err;
  	struct net *net = sock_net(sk);
  
  	if (inet_sk(sk)->transparent)
  		fl.flags |= FLOWI_FLAG_ANYSRC;
  
  	if (!dst || !src) {
  		err = __ip_route_output_key(net, rp, &fl);
  		if (err)
  			return err;
  		fl.fl4_dst = (*rp)->rt_dst;
  		fl.fl4_src = (*rp)->rt_src;
  		ip_rt_put(*rp);
  		*rp = NULL;
  	}
  	security_sk_classify_flow(sk, &fl);
  	return ip_route_output_flow(net, rp, &fl, sk, flags);
  }
  
  static inline int ip_route_newports(struct rtable **rp, u8 protocol,
  				    __be16 sport, __be16 dport, struct sock *sk)
  {
  	if (sport != (*rp)->fl.fl_ip_sport ||
  	    dport != (*rp)->fl.fl_ip_dport) {
  		struct flowi fl;
  
  		memcpy(&fl, &(*rp)->fl, sizeof(fl));
  		fl.fl_ip_sport = sport;
  		fl.fl_ip_dport = dport;
  		fl.proto = protocol;
  		if (inet_sk(sk)->transparent)
  			fl.flags |= FLOWI_FLAG_ANYSRC;
  		ip_rt_put(*rp);
  		*rp = NULL;
  		security_sk_classify_flow(sk, &fl);
  		return ip_route_output_flow(sock_net(sk), rp, &fl, sk, 0);
  	}
  	return 0;
  }
  
  extern void rt_bind_peer(struct rtable *rt, int create);
  
  static inline struct inet_peer *rt_get_peer(struct rtable *rt)
  {
  	if (rt->peer)
  		return rt->peer;
  
  	rt_bind_peer(rt, 0);
  	return rt->peer;
  }
  
  static inline int inet_iif(const struct sk_buff *skb)
  {
  	return skb_rtable(skb)->rt_iif;
  }
  
  #endif	/* _ROUTE_H */
  