LXR linux/include/net/route.h

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4 *              operating system.  INET  is implemented using the  BSD Socket
   5 *              interface as the means of communication with the user level.
   6 *
   7 *              Definitions for the IP router.
   8 *
   9 * Version:     @(#)route.h     1.0.4   05/27/93
  10 *
  11 * Authors:     Ross Biro
  12 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  13 * Fixes:
  14 *              Alan Cox        :       Reformatted. Added ip_rt_local()
  15 *              Alan Cox        :       Support for TCP parameters.
  16 *              Alexey Kuznetsov:       Major changes for new routing code.
  17 *              Mike McLagan    :       Routing by source
  18 *              Robert Olsson   :       Added rt_cache statistics
  19 */
  20#ifndef _ROUTE_H
  21#define _ROUTE_H
  22
  23#include <net/dst.h>
  24#include <net/inetpeer.h>
  25#include <net/flow.h>
  26#include <net/inet_sock.h>
  27#include <net/ip_fib.h>
  28#include <net/arp.h>
  29#include <net/ndisc.h>
  30#include <linux/in_route.h>
  31#include <linux/rtnetlink.h>
  32#include <linux/rcupdate.h>
  33#include <linux/route.h>
  34#include <linux/ip.h>
  35#include <linux/cache.h>
  36#include <linux/security.h>
  37
  38/* IPv4 datagram length is stored into 16bit field (tot_len) */
  39#define IP_MAX_MTU      0xFFFFU
  40
  41#define RTO_ONLINK      0x01
  42
  43#define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
  44#define RT_CONN_FLAGS_TOS(sk,tos)   (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
  45
  46struct fib_nh;
  47struct fib_info;
  48struct uncached_list;
  49struct rtable {
  50        struct dst_entry        dst;
  51
  52        int                     rt_genid;
  53        unsigned int            rt_flags;
  54        __u16                   rt_type;
  55        __u8                    rt_is_input;
  56        __u8                    rt_uses_gateway;
  57
  58        int                     rt_iif;
  59
  60        u8                      rt_gw_family;
  61        /* Info on neighbour */
  62        union {
  63                __be32          rt_gw4;
  64                struct in6_addr rt_gw6;
  65        };
  66
  67        /* Miscellaneous cached information */
  68        u32                     rt_mtu_locked:1,
  69                                rt_pmtu:31;
  70
  71        struct list_head        rt_uncached;
  72        struct uncached_list    *rt_uncached_list;
  73};
  74
  75static inline bool rt_is_input_route(const struct rtable *rt)
  76{
  77        return rt->rt_is_input != 0;
  78}
  79
  80static inline bool rt_is_output_route(const struct rtable *rt)
  81{
  82        return rt->rt_is_input == 0;
  83}
  84
  85static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
  86{
  87        if (rt->rt_gw_family == AF_INET)
  88                return rt->rt_gw4;
  89        return daddr;
  90}
  91
  92struct ip_rt_acct {
  93        __u32   o_bytes;
  94        __u32   o_packets;
  95        __u32   i_bytes;
  96        __u32   i_packets;
  97};
  98
  99struct rt_cache_stat {
 100        unsigned int in_slow_tot;
 101        unsigned int in_slow_mc;
 102        unsigned int in_no_route;
 103        unsigned int in_brd;
 104        unsigned int in_martian_dst;
 105        unsigned int in_martian_src;
 106        unsigned int out_slow_tot;
 107        unsigned int out_slow_mc;
 108};
 109
 110extern struct ip_rt_acct __percpu *ip_rt_acct;
 111
 112struct in_device;
 113
 114int ip_rt_init(void);
 115void rt_cache_flush(struct net *net);
 116void rt_flush_dev(struct net_device *dev);
 117struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
 118                                        const struct sk_buff *skb);
 119struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
 120                                            struct fib_result *res,
 121                                            const struct sk_buff *skb);
 122
 123static inline struct rtable *__ip_route_output_key(struct net *net,
 124                                                   struct flowi4 *flp)
 125{
 126        return ip_route_output_key_hash(net, flp, NULL);
 127}
 128
 129struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 130                                    const struct sock *sk);
 131struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
 132                                      struct net_device *dev,
 133                                      struct net *net, __be32 *saddr,
 134                                      const struct ip_tunnel_info *info,
 135                                      u8 protocol, bool use_cache);
 136
 137struct dst_entry *ipv4_blackhole_route(struct net *net,
 138                                       struct dst_entry *dst_orig);
 139
 140static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 141{
 142        return ip_route_output_flow(net, flp, NULL);
 143}
 144
 145static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 146                                             __be32 saddr, u8 tos, int oif)
 147{
 148        struct flowi4 fl4 = {
 149                .flowi4_oif = oif,
 150                .flowi4_tos = tos,
 151                .daddr = daddr,
 152                .saddr = saddr,
 153        };
 154        return ip_route_output_key(net, &fl4);
 155}
 156
 157static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 158                                                   struct sock *sk,
 159                                                   __be32 daddr, __be32 saddr,
 160                                                   __be16 dport, __be16 sport,
 161                                                   __u8 proto, __u8 tos, int oif)
 162{
 163        flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 164                           RT_SCOPE_UNIVERSE, proto,
 165                           sk ? inet_sk_flowi_flags(sk) : 0,
 166                           daddr, saddr, dport, sport, sock_net_uid(net, sk));
 167        if (sk)
 168                security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
 169        return ip_route_output_flow(net, fl4, sk);
 170}
 171
 172static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 173                                                 __be32 daddr, __be32 saddr,
 174                                                 __be32 gre_key, __u8 tos, int oif)
 175{
 176        memset(fl4, 0, sizeof(*fl4));
 177        fl4->flowi4_oif = oif;
 178        fl4->daddr = daddr;
 179        fl4->saddr = saddr;
 180        fl4->flowi4_tos = tos;
 181        fl4->flowi4_proto = IPPROTO_GRE;
 182        fl4->fl4_gre_key = gre_key;
 183        return ip_route_output_key(net, fl4);
 184}
 185int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 186                          u8 tos, struct net_device *dev,
 187                          struct in_device *in_dev, u32 *itag);
 188int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 189                         u8 tos, struct net_device *devin);
 190int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
 191                       u8 tos, struct net_device *devin,
 192                       struct fib_result *res);
 193
 194int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
 195                      u8 tos, struct net_device *devin,
 196                      const struct sk_buff *hint);
 197
 198static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 199                                 u8 tos, struct net_device *devin)
 200{
 201        int err;
 202
 203        rcu_read_lock();
 204        err = ip_route_input_noref(skb, dst, src, tos, devin);
 205        if (!err) {
 206                skb_dst_force(skb);
 207                if (!skb_dst(skb))
 208                        err = -EINVAL;
 209        }
 210        rcu_read_unlock();
 211
 212        return err;
 213}
 214
 215void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
 216                      u8 protocol);
 217void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
 218void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
 219void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
 220void ip_rt_send_redirect(struct sk_buff *skb);
 221
 222unsigned int inet_addr_type(struct net *net, __be32 addr);
 223unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
 224unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 225                                __be32 addr);
 226unsigned int inet_addr_type_dev_table(struct net *net,
 227                                      const struct net_device *dev,
 228                                      __be32 addr);
 229void ip_rt_multicast_event(struct in_device *);
 230int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
 231void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 232struct rtable *rt_dst_alloc(struct net_device *dev,
 233                             unsigned int flags, u16 type,
 234                             bool nopolicy, bool noxfrm);
 235struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
 236
 237struct in_ifaddr;
 238void fib_add_ifaddr(struct in_ifaddr *);
 239void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 240void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
 241
 242void rt_add_uncached_list(struct rtable *rt);
 243void rt_del_uncached_list(struct rtable *rt);
 244
 245int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
 246                       u32 table_id, struct fib_info *fi,
 247                       int *fa_index, int fa_start, unsigned int flags);
 248
 249static inline void ip_rt_put(struct rtable *rt)
 250{
 251        /* dst_release() accepts a NULL parameter.
 252         * We rely on dst being first structure in struct rtable
 253         */
 254        BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
 255        dst_release(&rt->dst);
 256}
 257
 258#define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 259
 260extern const __u8 ip_tos2prio[16];
 261
 262static inline char rt_tos2priority(u8 tos)
 263{
 264        return ip_tos2prio[IPTOS_TOS(tos)>>1];
 265}
 266
 267/* ip_route_connect() and ip_route_newports() work in tandem whilst
 268 * binding a socket for a new outgoing connection.
 269 *
 270 * In order to use IPSEC properly, we must, in the end, have a
 271 * route that was looked up using all available keys including source
 272 * and destination ports.
 273 *
 274 * However, if a source port needs to be allocated (the user specified
 275 * a wildcard source port) we need to obtain addressing information
 276 * in order to perform that allocation.
 277 *
 278 * So ip_route_connect() looks up a route using wildcarded source and
 279 * destination ports in the key, simply so that we can get a pair of
 280 * addresses to use for port allocation.
 281 *
 282 * Later, once the ports are allocated, ip_route_newports() will make
 283 * another route lookup if needed to make sure we catch any IPSEC
 284 * rules keyed on the port information.
 285 *
 286 * The callers allocate the flow key on their stack, and must pass in
 287 * the same flowi4 object to both the ip_route_connect() and the
 288 * ip_route_newports() calls.
 289 */
 290
 291static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 292                                         u32 tos, int oif, u8 protocol,
 293                                         __be16 sport, __be16 dport,
 294                                         struct sock *sk)
 295{
 296        __u8 flow_flags = 0;
 297
 298        if (inet_sk(sk)->transparent)
 299                flow_flags |= FLOWI_FLAG_ANYSRC;
 300
 301        flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 302                           protocol, flow_flags, dst, src, dport, sport,
 303                           sk->sk_uid);
 304}
 305
 306static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 307                                              __be32 dst, __be32 src, u32 tos,
 308                                              int oif, u8 protocol,
 309                                              __be16 sport, __be16 dport,
 310                                              struct sock *sk)
 311{
 312        struct net *net = sock_net(sk);
 313        struct rtable *rt;
 314
 315        ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 316                              sport, dport, sk);
 317
 318        if (!dst || !src) {
 319                rt = __ip_route_output_key(net, fl4);
 320                if (IS_ERR(rt))
 321                        return rt;
 322                ip_rt_put(rt);
 323                flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
 324        }
 325        security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
 326        return ip_route_output_flow(net, fl4, sk);
 327}
 328
 329static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
 330                                               __be16 orig_sport, __be16 orig_dport,
 331                                               __be16 sport, __be16 dport,
 332                                               struct sock *sk)
 333{
 334        if (sport != orig_sport || dport != orig_dport) {
 335                fl4->fl4_dport = dport;
 336                fl4->fl4_sport = sport;
 337                ip_rt_put(rt);
 338                flowi4_update_output(fl4, sk->sk_bound_dev_if,
 339                                     RT_CONN_FLAGS(sk), fl4->daddr,
 340                                     fl4->saddr);
 341                security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
 342                return ip_route_output_flow(sock_net(sk), fl4, sk);
 343        }
 344        return rt;
 345}
 346
 347static inline int inet_iif(const struct sk_buff *skb)
 348{
 349        struct rtable *rt = skb_rtable(skb);
 350
 351        if (rt && rt->rt_iif)
 352                return rt->rt_iif;
 353
 354        return skb->skb_iif;
 355}
 356
 357static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 358{
 359        int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 360        struct net *net = dev_net(dst->dev);
 361
 362        if (hoplimit == 0)
 363                hoplimit = net->ipv4.sysctl_ip_default_ttl;
 364        return hoplimit;
 365}
 366
 367static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
 368                                             __be32 daddr)
 369{
 370        struct neighbour *neigh;
 371
 372        neigh = __ipv4_neigh_lookup_noref(dev, daddr);
 373        if (unlikely(!neigh))
 374                neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
 375
 376        return neigh;
 377}
 378
 379static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
 380                                                struct sk_buff *skb,
 381                                                bool *is_v6gw)
 382{
 383        struct net_device *dev = rt->dst.dev;
 384        struct neighbour *neigh;
 385
 386        if (likely(rt->rt_gw_family == AF_INET)) {
 387                neigh = ip_neigh_gw4(dev, rt->rt_gw4);
 388        } else if (rt->rt_gw_family == AF_INET6) {
 389                neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
 390                *is_v6gw = true;
 391        } else {
 392                neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
 393        }
 394        return neigh;
 395}
 396
 397#endif  /* _ROUTE_H */
 398