linux/include/net/route.h
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   1/*
   2 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3 *              operating system.  INET  is implemented using the  BSD Socket
   4 *              interface as the means of communication with the user level.
   5 *
   6 *              Definitions for the IP router.
   7 *
   8 * Version:     @(#)route.h     1.0.4   05/27/93
   9 *
  10 * Authors:     Ross Biro
  11 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12 * Fixes:
  13 *              Alan Cox        :       Reformatted. Added ip_rt_local()
  14 *              Alan Cox        :       Support for TCP parameters.
  15 *              Alexey Kuznetsov:       Major changes for new routing code.
  16 *              Mike McLagan    :       Routing by source
  17 *              Robert Olsson   :       Added rt_cache statistics
  18 *
  19 *              This program is free software; you can redistribute it and/or
  20 *              modify it under the terms of the GNU General Public License
  21 *              as published by the Free Software Foundation; either version
  22 *              2 of the License, or (at your option) any later version.
  23 */
  24#ifndef _ROUTE_H
  25#define _ROUTE_H
  26
  27#include <net/dst.h>
  28#include <net/inetpeer.h>
  29#include <net/flow.h>
  30#include <net/inet_sock.h>
  31#include <linux/in_route.h>
  32#include <linux/rtnetlink.h>
  33#include <linux/rcupdate.h>
  34#include <linux/route.h>
  35#include <linux/ip.h>
  36#include <linux/cache.h>
  37#include <linux/security.h>
  38
  39#define RTO_ONLINK      0x01
  40
  41#define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
  42
  43struct fib_nh;
  44struct fib_info;
  45struct rtable {
  46        struct dst_entry        dst;
  47
  48        int                     rt_genid;
  49        unsigned int            rt_flags;
  50        __u16                   rt_type;
  51        __u8                    rt_is_input;
  52        __u8                    rt_uses_gateway;
  53
  54        int                     rt_iif;
  55
  56        /* Info on neighbour */
  57        __be32                  rt_gateway;
  58
  59        /* Miscellaneous cached information */
  60        u32                     rt_pmtu;
  61
  62        struct list_head        rt_uncached;
  63};
  64
  65static inline bool rt_is_input_route(const struct rtable *rt)
  66{
  67        return rt->rt_is_input != 0;
  68}
  69
  70static inline bool rt_is_output_route(const struct rtable *rt)
  71{
  72        return rt->rt_is_input == 0;
  73}
  74
  75static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
  76{
  77        if (rt->rt_gateway)
  78                return rt->rt_gateway;
  79        return daddr;
  80}
  81
  82struct ip_rt_acct {
  83        __u32   o_bytes;
  84        __u32   o_packets;
  85        __u32   i_bytes;
  86        __u32   i_packets;
  87};
  88
  89struct rt_cache_stat {
  90        unsigned int in_hit;
  91        unsigned int in_slow_tot;
  92        unsigned int in_slow_mc;
  93        unsigned int in_no_route;
  94        unsigned int in_brd;
  95        unsigned int in_martian_dst;
  96        unsigned int in_martian_src;
  97        unsigned int out_hit;
  98        unsigned int out_slow_tot;
  99        unsigned int out_slow_mc;
 100        unsigned int gc_total;
 101        unsigned int gc_ignored;
 102        unsigned int gc_goal_miss;
 103        unsigned int gc_dst_overflow;
 104        unsigned int in_hlist_search;
 105        unsigned int out_hlist_search;
 106};
 107
 108extern struct ip_rt_acct __percpu *ip_rt_acct;
 109
 110struct in_device;
 111extern int              ip_rt_init(void);
 112extern void             rt_cache_flush(struct net *net);
 113extern void             rt_flush_dev(struct net_device *dev);
 114extern struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
 115extern struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 116                                           struct sock *sk);
 117extern struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig);
 118
 119static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 120{
 121        return ip_route_output_flow(net, flp, NULL);
 122}
 123
 124static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 125                                             __be32 saddr, u8 tos, int oif)
 126{
 127        struct flowi4 fl4 = {
 128                .flowi4_oif = oif,
 129                .flowi4_tos = tos,
 130                .daddr = daddr,
 131                .saddr = saddr,
 132        };
 133        return ip_route_output_key(net, &fl4);
 134}
 135
 136static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 137                                                   struct sock *sk,
 138                                                   __be32 daddr, __be32 saddr,
 139                                                   __be16 dport, __be16 sport,
 140                                                   __u8 proto, __u8 tos, int oif)
 141{
 142        flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 143                           RT_SCOPE_UNIVERSE, proto,
 144                           sk ? inet_sk_flowi_flags(sk) : 0,
 145                           daddr, saddr, dport, sport);
 146        if (sk)
 147                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 148        return ip_route_output_flow(net, fl4, sk);
 149}
 150
 151static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 152                                                 __be32 daddr, __be32 saddr,
 153                                                 __be32 gre_key, __u8 tos, int oif)
 154{
 155        memset(fl4, 0, sizeof(*fl4));
 156        fl4->flowi4_oif = oif;
 157        fl4->daddr = daddr;
 158        fl4->saddr = saddr;
 159        fl4->flowi4_tos = tos;
 160        fl4->flowi4_proto = IPPROTO_GRE;
 161        fl4->fl4_gre_key = gre_key;
 162        return ip_route_output_key(net, fl4);
 163}
 164
 165extern int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 166                                u8 tos, struct net_device *devin);
 167
 168static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 169                                 u8 tos, struct net_device *devin)
 170{
 171        int err;
 172
 173        rcu_read_lock();
 174        err = ip_route_input_noref(skb, dst, src, tos, devin);
 175        if (!err)
 176                skb_dst_force(skb);
 177        rcu_read_unlock();
 178
 179        return err;
 180}
 181
 182extern void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
 183                             int oif, u32 mark, u8 protocol, int flow_flags);
 184extern void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
 185extern void ipv4_redirect(struct sk_buff *skb, struct net *net,
 186                          int oif, u32 mark, u8 protocol, int flow_flags);
 187extern void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
 188extern void ip_rt_send_redirect(struct sk_buff *skb);
 189
 190extern unsigned int             inet_addr_type(struct net *net, __be32 addr);
 191extern unsigned int             inet_dev_addr_type(struct net *net, const struct net_device *dev, __be32 addr);
 192extern void             ip_rt_multicast_event(struct in_device *);
 193extern int              ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
 194extern void             ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 195extern int              ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb);
 196
 197struct in_ifaddr;
 198extern void fib_add_ifaddr(struct in_ifaddr *);
 199extern void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 200
 201static inline void ip_rt_put(struct rtable * rt)
 202{
 203        if (rt)
 204                dst_release(&rt->dst);
 205}
 206
 207#define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 208
 209extern const __u8 ip_tos2prio[16];
 210
 211static inline char rt_tos2priority(u8 tos)
 212{
 213        return ip_tos2prio[IPTOS_TOS(tos)>>1];
 214}
 215
 216/* ip_route_connect() and ip_route_newports() work in tandem whilst
 217 * binding a socket for a new outgoing connection.
 218 *
 219 * In order to use IPSEC properly, we must, in the end, have a
 220 * route that was looked up using all available keys including source
 221 * and destination ports.
 222 *
 223 * However, if a source port needs to be allocated (the user specified
 224 * a wildcard source port) we need to obtain addressing information
 225 * in order to perform that allocation.
 226 *
 227 * So ip_route_connect() looks up a route using wildcarded source and
 228 * destination ports in the key, simply so that we can get a pair of
 229 * addresses to use for port allocation.
 230 *
 231 * Later, once the ports are allocated, ip_route_newports() will make
 232 * another route lookup if needed to make sure we catch any IPSEC
 233 * rules keyed on the port information.
 234 *
 235 * The callers allocate the flow key on their stack, and must pass in
 236 * the same flowi4 object to both the ip_route_connect() and the
 237 * ip_route_newports() calls.
 238 */
 239
 240static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 241                                         u32 tos, int oif, u8 protocol,
 242                                         __be16 sport, __be16 dport,
 243                                         struct sock *sk, bool can_sleep)
 244{
 245        __u8 flow_flags = 0;
 246
 247        if (inet_sk(sk)->transparent)
 248                flow_flags |= FLOWI_FLAG_ANYSRC;
 249        if (can_sleep)
 250                flow_flags |= FLOWI_FLAG_CAN_SLEEP;
 251
 252        flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 253                           protocol, flow_flags, dst, src, dport, sport);
 254}
 255
 256static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 257                                              __be32 dst, __be32 src, u32 tos,
 258                                              int oif, u8 protocol,
 259                                              __be16 sport, __be16 dport,
 260                                              struct sock *sk, bool can_sleep)
 261{
 262        struct net *net = sock_net(sk);
 263        struct rtable *rt;
 264
 265        ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 266                              sport, dport, sk, can_sleep);
 267
 268        if (!dst || !src) {
 269                rt = __ip_route_output_key(net, fl4);
 270                if (IS_ERR(rt))
 271                        return rt;
 272                ip_rt_put(rt);
 273                flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
 274        }
 275        security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 276        return ip_route_output_flow(net, fl4, sk);
 277}
 278
 279static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
 280                                               __be16 orig_sport, __be16 orig_dport,
 281                                               __be16 sport, __be16 dport,
 282                                               struct sock *sk)
 283{
 284        if (sport != orig_sport || dport != orig_dport) {
 285                fl4->fl4_dport = dport;
 286                fl4->fl4_sport = sport;
 287                ip_rt_put(rt);
 288                flowi4_update_output(fl4, sk->sk_bound_dev_if,
 289                                     RT_CONN_FLAGS(sk), fl4->daddr,
 290                                     fl4->saddr);
 291                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 292                return ip_route_output_flow(sock_net(sk), fl4, sk);
 293        }
 294        return rt;
 295}
 296
 297static inline int inet_iif(const struct sk_buff *skb)
 298{
 299        int iif = skb_rtable(skb)->rt_iif;
 300
 301        if (iif)
 302                return iif;
 303        return skb->skb_iif;
 304}
 305
 306extern int sysctl_ip_default_ttl;
 307
 308static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 309{
 310        int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 311
 312        if (hoplimit == 0)
 313                hoplimit = sysctl_ip_default_ttl;
 314        return hoplimit;
 315}
 316
 317#endif  /* _ROUTE_H */
 318
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