LXR linux/include/net/route.h

   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 <net/ip_fib.h>
  32#include <linux/in_route.h>
  33#include <linux/rtnetlink.h>
  34#include <linux/rcupdate.h>
  35#include <linux/route.h>
  36#include <linux/ip.h>
  37#include <linux/cache.h>
  38#include <linux/security.h>
  39
  40/* IPv4 datagram length is stored into 16bit field (tot_len) */
  41#define IP_MAX_MTU      0xFFFFU
  42
  43#define RTO_ONLINK      0x01
  44
  45#define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
  46#define RT_CONN_FLAGS_TOS(sk,tos)   (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
  47
  48struct fib_nh;
  49struct fib_info;
  50struct uncached_list;
  51struct rtable {
  52        struct dst_entry        dst;
  53
  54        int                     rt_genid;
  55        unsigned int            rt_flags;
  56        __u16                   rt_type;
  57        __u8                    rt_is_input;
  58        __u8                    rt_uses_gateway;
  59
  60        int                     rt_iif;
  61
  62        /* Info on neighbour */
  63        __be32                  rt_gateway;
  64
  65        /* Miscellaneous cached information */
  66        u32                     rt_pmtu;
  67
  68        u32                     rt_table_id;
  69
  70        struct list_head        rt_uncached;
  71        struct uncached_list    *rt_uncached_list;
  72};
  73
  74static inline bool rt_is_input_route(const struct rtable *rt)
  75{
  76        return rt->rt_is_input != 0;
  77}
  78
  79static inline bool rt_is_output_route(const struct rtable *rt)
  80{
  81        return rt->rt_is_input == 0;
  82}
  83
  84static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
  85{
  86        if (rt->rt_gateway)
  87                return rt->rt_gateway;
  88        return daddr;
  89}
  90
  91struct ip_rt_acct {
  92        __u32   o_bytes;
  93        __u32   o_packets;
  94        __u32   i_bytes;
  95        __u32   i_packets;
  96};
  97
  98struct rt_cache_stat {
  99        unsigned int in_slow_tot;
 100        unsigned int in_slow_mc;
 101        unsigned int in_no_route;
 102        unsigned int in_brd;
 103        unsigned int in_martian_dst;
 104        unsigned int in_martian_src;
 105        unsigned int out_slow_tot;
 106        unsigned int out_slow_mc;
 107};
 108
 109extern struct ip_rt_acct __percpu *ip_rt_acct;
 110
 111struct in_device;
 112
 113int ip_rt_init(void);
 114void rt_cache_flush(struct net *net);
 115void rt_flush_dev(struct net_device *dev);
 116struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
 117                                        const struct sk_buff *skb);
 118struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
 119                                            struct fib_result *res,
 120                                            const struct sk_buff *skb);
 121
 122static inline struct rtable *__ip_route_output_key(struct net *net,
 123                                                   struct flowi4 *flp)
 124{
 125        return ip_route_output_key_hash(net, flp, NULL);
 126}
 127
 128struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 129                                    const struct sock *sk);
 130struct dst_entry *ipv4_blackhole_route(struct net *net,
 131                                       struct dst_entry *dst_orig);
 132
 133static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 134{
 135        return ip_route_output_flow(net, flp, NULL);
 136}
 137
 138static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 139                                             __be32 saddr, u8 tos, int oif)
 140{
 141        struct flowi4 fl4 = {
 142                .flowi4_oif = oif,
 143                .flowi4_tos = tos,
 144                .daddr = daddr,
 145                .saddr = saddr,
 146        };
 147        return ip_route_output_key(net, &fl4);
 148}
 149
 150static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 151                                                   struct sock *sk,
 152                                                   __be32 daddr, __be32 saddr,
 153                                                   __be16 dport, __be16 sport,
 154                                                   __u8 proto, __u8 tos, int oif)
 155{
 156        flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 157                           RT_SCOPE_UNIVERSE, proto,
 158                           sk ? inet_sk_flowi_flags(sk) : 0,
 159                           daddr, saddr, dport, sport, sock_net_uid(net, sk));
 160        if (sk)
 161                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 162        return ip_route_output_flow(net, fl4, sk);
 163}
 164
 165static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 166                                                 __be32 daddr, __be32 saddr,
 167                                                 __be32 gre_key, __u8 tos, int oif)
 168{
 169        memset(fl4, 0, sizeof(*fl4));
 170        fl4->flowi4_oif = oif;
 171        fl4->daddr = daddr;
 172        fl4->saddr = saddr;
 173        fl4->flowi4_tos = tos;
 174        fl4->flowi4_proto = IPPROTO_GRE;
 175        fl4->fl4_gre_key = gre_key;
 176        return ip_route_output_key(net, fl4);
 177}
 178int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 179                          u8 tos, struct net_device *dev,
 180                          struct in_device *in_dev, u32 *itag);
 181int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 182                         u8 tos, struct net_device *devin);
 183int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
 184                       u8 tos, struct net_device *devin,
 185                       struct fib_result *res);
 186
 187static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 188                                 u8 tos, struct net_device *devin)
 189{
 190        int err;
 191
 192        rcu_read_lock();
 193        err = ip_route_input_noref(skb, dst, src, tos, devin);
 194        if (!err) {
 195                skb_dst_force(skb);
 196                if (!skb_dst(skb))
 197                        err = -EINVAL;
 198        }
 199        rcu_read_unlock();
 200
 201        return err;
 202}
 203
 204void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
 205                      u32 mark, u8 protocol, int flow_flags);
 206void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
 207void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
 208                   u8 protocol, int flow_flags);
 209void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
 210void ip_rt_send_redirect(struct sk_buff *skb);
 211
 212unsigned int inet_addr_type(struct net *net, __be32 addr);
 213unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
 214unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 215                                __be32 addr);
 216unsigned int inet_addr_type_dev_table(struct net *net,
 217                                      const struct net_device *dev,
 218                                      __be32 addr);
 219void ip_rt_multicast_event(struct in_device *);
 220int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
 221void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 222struct rtable *rt_dst_alloc(struct net_device *dev,
 223                             unsigned int flags, u16 type,
 224                             bool nopolicy, bool noxfrm, bool will_cache);
 225
 226struct in_ifaddr;
 227void fib_add_ifaddr(struct in_ifaddr *);
 228void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 229
 230static inline void ip_rt_put(struct rtable *rt)
 231{
 232        /* dst_release() accepts a NULL parameter.
 233         * We rely on dst being first structure in struct rtable
 234         */
 235        BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
 236        dst_release(&rt->dst);
 237}
 238
 239#define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 240
 241extern const __u8 ip_tos2prio[16];
 242
 243static inline char rt_tos2priority(u8 tos)
 244{
 245        return ip_tos2prio[IPTOS_TOS(tos)>>1];
 246}
 247
 248/* ip_route_connect() and ip_route_newports() work in tandem whilst
 249 * binding a socket for a new outgoing connection.
 250 *
 251 * In order to use IPSEC properly, we must, in the end, have a
 252 * route that was looked up using all available keys including source
 253 * and destination ports.
 254 *
 255 * However, if a source port needs to be allocated (the user specified
 256 * a wildcard source port) we need to obtain addressing information
 257 * in order to perform that allocation.
 258 *
 259 * So ip_route_connect() looks up a route using wildcarded source and
 260 * destination ports in the key, simply so that we can get a pair of
 261 * addresses to use for port allocation.
 262 *
 263 * Later, once the ports are allocated, ip_route_newports() will make
 264 * another route lookup if needed to make sure we catch any IPSEC
 265 * rules keyed on the port information.
 266 *
 267 * The callers allocate the flow key on their stack, and must pass in
 268 * the same flowi4 object to both the ip_route_connect() and the
 269 * ip_route_newports() calls.
 270 */
 271
 272static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 273                                         u32 tos, int oif, u8 protocol,
 274                                         __be16 sport, __be16 dport,
 275                                         struct sock *sk)
 276{
 277        __u8 flow_flags = 0;
 278
 279        if (inet_sk(sk)->transparent)
 280                flow_flags |= FLOWI_FLAG_ANYSRC;
 281
 282        flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 283                           protocol, flow_flags, dst, src, dport, sport,
 284                           sk->sk_uid);
 285}
 286
 287static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 288                                              __be32 dst, __be32 src, u32 tos,
 289                                              int oif, u8 protocol,
 290                                              __be16 sport, __be16 dport,
 291                                              struct sock *sk)
 292{
 293        struct net *net = sock_net(sk);
 294        struct rtable *rt;
 295
 296        ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 297                              sport, dport, sk);
 298
 299        if (!dst || !src) {
 300                rt = __ip_route_output_key(net, fl4);
 301                if (IS_ERR(rt))
 302                        return rt;
 303                ip_rt_put(rt);
 304                flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
 305        }
 306        security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 307        return ip_route_output_flow(net, fl4, sk);
 308}
 309
 310static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
 311                                               __be16 orig_sport, __be16 orig_dport,
 312                                               __be16 sport, __be16 dport,
 313                                               struct sock *sk)
 314{
 315        if (sport != orig_sport || dport != orig_dport) {
 316                fl4->fl4_dport = dport;
 317                fl4->fl4_sport = sport;
 318                ip_rt_put(rt);
 319                flowi4_update_output(fl4, sk->sk_bound_dev_if,
 320                                     RT_CONN_FLAGS(sk), fl4->daddr,
 321                                     fl4->saddr);
 322                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 323                return ip_route_output_flow(sock_net(sk), fl4, sk);
 324        }
 325        return rt;
 326}
 327
 328static inline int inet_iif(const struct sk_buff *skb)
 329{
 330        struct rtable *rt = skb_rtable(skb);
 331
 332        if (rt && rt->rt_iif)
 333                return rt->rt_iif;
 334
 335        return skb->skb_iif;
 336}
 337
 338static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 339{
 340        int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 341        struct net *net = dev_net(dst->dev);
 342
 343        if (hoplimit == 0)
 344                hoplimit = net->ipv4.sysctl_ip_default_ttl;
 345        return hoplimit;
 346}
 347
 348#endif  /* _ROUTE_H */
 349