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_mtu_locked:1,
  67                                rt_pmtu:31;
  68
  69        struct list_head        rt_uncached;
  70        struct uncached_list    *rt_uncached_list;
  71};
  72
  73static inline bool rt_is_input_route(const struct rtable *rt)
  74{
  75        return rt->rt_is_input != 0;
  76}
  77
  78static inline bool rt_is_output_route(const struct rtable *rt)
  79{
  80        return rt->rt_is_input == 0;
  81}
  82
  83static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
  84{
  85        if (rt->rt_gateway)
  86                return rt->rt_gateway;
  87        return daddr;
  88}
  89
  90struct ip_rt_acct {
  91        __u32   o_bytes;
  92        __u32   o_packets;
  93        __u32   i_bytes;
  94        __u32   i_packets;
  95};
  96
  97struct rt_cache_stat {
  98        unsigned int in_slow_tot;
  99        unsigned int in_slow_mc;
 100        unsigned int in_no_route;
 101        unsigned int in_brd;
 102        unsigned int in_martian_dst;
 103        unsigned int in_martian_src;
 104        unsigned int out_slow_tot;
 105        unsigned int out_slow_mc;
 106};
 107
 108extern struct ip_rt_acct __percpu *ip_rt_acct;
 109
 110struct in_device;
 111
 112int ip_rt_init(void);
 113void rt_cache_flush(struct net *net);
 114void rt_flush_dev(struct net_device *dev);
 115struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
 116                                        const struct sk_buff *skb);
 117struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
 118                                            struct fib_result *res,
 119                                            const struct sk_buff *skb);
 120
 121static inline struct rtable *__ip_route_output_key(struct net *net,
 122                                                   struct flowi4 *flp)
 123{
 124        return ip_route_output_key_hash(net, flp, NULL);
 125}
 126
 127struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 128                                    const struct sock *sk);
 129struct dst_entry *ipv4_blackhole_route(struct net *net,
 130                                       struct dst_entry *dst_orig);
 131
 132static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 133{
 134        return ip_route_output_flow(net, flp, NULL);
 135}
 136
 137static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 138                                             __be32 saddr, u8 tos, int oif)
 139{
 140        struct flowi4 fl4 = {
 141                .flowi4_oif = oif,
 142                .flowi4_tos = tos,
 143                .daddr = daddr,
 144                .saddr = saddr,
 145        };
 146        return ip_route_output_key(net, &fl4);
 147}
 148
 149static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 150                                                   struct sock *sk,
 151                                                   __be32 daddr, __be32 saddr,
 152                                                   __be16 dport, __be16 sport,
 153                                                   __u8 proto, __u8 tos, int oif)
 154{
 155        flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 156                           RT_SCOPE_UNIVERSE, proto,
 157                           sk ? inet_sk_flowi_flags(sk) : 0,
 158                           daddr, saddr, dport, sport, sock_net_uid(net, sk));
 159        if (sk)
 160                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 161        return ip_route_output_flow(net, fl4, sk);
 162}
 163
 164static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 165                                                 __be32 daddr, __be32 saddr,
 166                                                 __be32 gre_key, __u8 tos, int oif)
 167{
 168        memset(fl4, 0, sizeof(*fl4));
 169        fl4->flowi4_oif = oif;
 170        fl4->daddr = daddr;
 171        fl4->saddr = saddr;
 172        fl4->flowi4_tos = tos;
 173        fl4->flowi4_proto = IPPROTO_GRE;
 174        fl4->fl4_gre_key = gre_key;
 175        return ip_route_output_key(net, fl4);
 176}
 177int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 178                          u8 tos, struct net_device *dev,
 179                          struct in_device *in_dev, u32 *itag);
 180int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 181                         u8 tos, struct net_device *devin);
 182int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
 183                       u8 tos, struct net_device *devin,
 184                       struct fib_result *res);
 185
 186static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 187                                 u8 tos, struct net_device *devin)
 188{
 189        int err;
 190
 191        rcu_read_lock();
 192        err = ip_route_input_noref(skb, dst, src, tos, devin);
 193        if (!err) {
 194                skb_dst_force(skb);
 195                if (!skb_dst(skb))
 196                        err = -EINVAL;
 197        }
 198        rcu_read_unlock();
 199
 200        return err;
 201}
 202
 203void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
 204                      u8 protocol);
 205void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
 206void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
 207void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
 208void ip_rt_send_redirect(struct sk_buff *skb);
 209
 210unsigned int inet_addr_type(struct net *net, __be32 addr);
 211unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
 212unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 213                                __be32 addr);
 214unsigned int inet_addr_type_dev_table(struct net *net,
 215                                      const struct net_device *dev,
 216                                      __be32 addr);
 217void ip_rt_multicast_event(struct in_device *);
 218int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
 219void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 220struct rtable *rt_dst_alloc(struct net_device *dev,
 221                             unsigned int flags, u16 type,
 222                             bool nopolicy, bool noxfrm, bool will_cache);
 223
 224struct in_ifaddr;
 225void fib_add_ifaddr(struct in_ifaddr *);
 226void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 227void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
 228
 229void rt_add_uncached_list(struct rtable *rt);
 230void rt_del_uncached_list(struct rtable *rt);
 231
 232static inline void ip_rt_put(struct rtable *rt)
 233{
 234        /* dst_release() accepts a NULL parameter.
 235         * We rely on dst being first structure in struct rtable
 236         */
 237        BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
 238        dst_release(&rt->dst);
 239}
 240
 241#define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 242
 243extern const __u8 ip_tos2prio[16];
 244
 245static inline char rt_tos2priority(u8 tos)
 246{
 247        return ip_tos2prio[IPTOS_TOS(tos)>>1];
 248}
 249
 250/* ip_route_connect() and ip_route_newports() work in tandem whilst
 251 * binding a socket for a new outgoing connection.
 252 *
 253 * In order to use IPSEC properly, we must, in the end, have a
 254 * route that was looked up using all available keys including source
 255 * and destination ports.
 256 *
 257 * However, if a source port needs to be allocated (the user specified
 258 * a wildcard source port) we need to obtain addressing information
 259 * in order to perform that allocation.
 260 *
 261 * So ip_route_connect() looks up a route using wildcarded source and
 262 * destination ports in the key, simply so that we can get a pair of
 263 * addresses to use for port allocation.
 264 *
 265 * Later, once the ports are allocated, ip_route_newports() will make
 266 * another route lookup if needed to make sure we catch any IPSEC
 267 * rules keyed on the port information.
 268 *
 269 * The callers allocate the flow key on their stack, and must pass in
 270 * the same flowi4 object to both the ip_route_connect() and the
 271 * ip_route_newports() calls.
 272 */
 273
 274static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 275                                         u32 tos, int oif, u8 protocol,
 276                                         __be16 sport, __be16 dport,
 277                                         struct sock *sk)
 278{
 279        __u8 flow_flags = 0;
 280
 281        if (inet_sk(sk)->transparent)
 282                flow_flags |= FLOWI_FLAG_ANYSRC;
 283
 284        flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 285                           protocol, flow_flags, dst, src, dport, sport,
 286                           sk->sk_uid);
 287}
 288
 289static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 290                                              __be32 dst, __be32 src, u32 tos,
 291                                              int oif, u8 protocol,
 292                                              __be16 sport, __be16 dport,
 293                                              struct sock *sk)
 294{
 295        struct net *net = sock_net(sk);
 296        struct rtable *rt;
 297
 298        ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 299                              sport, dport, sk);
 300
 301        if (!dst || !src) {
 302                rt = __ip_route_output_key(net, fl4);
 303                if (IS_ERR(rt))
 304                        return rt;
 305                ip_rt_put(rt);
 306                flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
 307        }
 308        security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 309        return ip_route_output_flow(net, fl4, sk);
 310}
 311
 312static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
 313                                               __be16 orig_sport, __be16 orig_dport,
 314                                               __be16 sport, __be16 dport,
 315                                               struct sock *sk)
 316{
 317        if (sport != orig_sport || dport != orig_dport) {
 318                fl4->fl4_dport = dport;
 319                fl4->fl4_sport = sport;
 320                ip_rt_put(rt);
 321                flowi4_update_output(fl4, sk->sk_bound_dev_if,
 322                                     RT_CONN_FLAGS(sk), fl4->daddr,
 323                                     fl4->saddr);
 324                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 325                return ip_route_output_flow(sock_net(sk), fl4, sk);
 326        }
 327        return rt;
 328}
 329
 330static inline int inet_iif(const struct sk_buff *skb)
 331{
 332        struct rtable *rt = skb_rtable(skb);
 333
 334        if (rt && rt->rt_iif)
 335                return rt->rt_iif;
 336
 337        return skb->skb_iif;
 338}
 339
 340static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 341{
 342        int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 343        struct net *net = dev_net(dst->dev);
 344
 345        if (hoplimit == 0)
 346                hoplimit = net->ipv4.sysctl_ip_default_ttl;
 347        return hoplimit;
 348}
 349
 350#endif  /* _ROUTE_H */
 351