linux/include/net/ip_fib.h
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   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 Forwarding Information Base.
   8 *
   9 * Authors:     A.N.Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10 */
  11
  12#ifndef _NET_IP_FIB_H
  13#define _NET_IP_FIB_H
  14
  15#include <net/flow.h>
  16#include <linux/seq_file.h>
  17#include <linux/rcupdate.h>
  18#include <net/fib_notifier.h>
  19#include <net/fib_rules.h>
  20#include <net/inetpeer.h>
  21#include <linux/percpu.h>
  22#include <linux/notifier.h>
  23#include <linux/refcount.h>
  24
  25struct fib_config {
  26        u8                      fc_dst_len;
  27        u8                      fc_tos;
  28        u8                      fc_protocol;
  29        u8                      fc_scope;
  30        u8                      fc_type;
  31        u8                      fc_gw_family;
  32        /* 2 bytes unused */
  33        u32                     fc_table;
  34        __be32                  fc_dst;
  35        union {
  36                __be32          fc_gw4;
  37                struct in6_addr fc_gw6;
  38        };
  39        int                     fc_oif;
  40        u32                     fc_flags;
  41        u32                     fc_priority;
  42        __be32                  fc_prefsrc;
  43        u32                     fc_nh_id;
  44        struct nlattr           *fc_mx;
  45        struct rtnexthop        *fc_mp;
  46        int                     fc_mx_len;
  47        int                     fc_mp_len;
  48        u32                     fc_flow;
  49        u32                     fc_nlflags;
  50        struct nl_info          fc_nlinfo;
  51        struct nlattr           *fc_encap;
  52        u16                     fc_encap_type;
  53};
  54
  55struct fib_info;
  56struct rtable;
  57
  58struct fib_nh_exception {
  59        struct fib_nh_exception __rcu   *fnhe_next;
  60        int                             fnhe_genid;
  61        __be32                          fnhe_daddr;
  62        u32                             fnhe_pmtu;
  63        bool                            fnhe_mtu_locked;
  64        __be32                          fnhe_gw;
  65        unsigned long                   fnhe_expires;
  66        struct rtable __rcu             *fnhe_rth_input;
  67        struct rtable __rcu             *fnhe_rth_output;
  68        unsigned long                   fnhe_stamp;
  69        struct rcu_head                 rcu;
  70};
  71
  72struct fnhe_hash_bucket {
  73        struct fib_nh_exception __rcu   *chain;
  74};
  75
  76#define FNHE_HASH_SHIFT         11
  77#define FNHE_HASH_SIZE          (1 << FNHE_HASH_SHIFT)
  78#define FNHE_RECLAIM_DEPTH      5
  79
  80struct fib_nh_common {
  81        struct net_device       *nhc_dev;
  82        int                     nhc_oif;
  83        unsigned char           nhc_scope;
  84        u8                      nhc_family;
  85        u8                      nhc_gw_family;
  86        unsigned char           nhc_flags;
  87        struct lwtunnel_state   *nhc_lwtstate;
  88
  89        union {
  90                __be32          ipv4;
  91                struct in6_addr ipv6;
  92        } nhc_gw;
  93
  94        int                     nhc_weight;
  95        atomic_t                nhc_upper_bound;
  96
  97        /* v4 specific, but allows fib6_nh with v4 routes */
  98        struct rtable __rcu * __percpu *nhc_pcpu_rth_output;
  99        struct rtable __rcu     *nhc_rth_input;
 100        struct fnhe_hash_bucket __rcu *nhc_exceptions;
 101};
 102
 103struct fib_nh {
 104        struct fib_nh_common    nh_common;
 105        struct hlist_node       nh_hash;
 106        struct fib_info         *nh_parent;
 107#ifdef CONFIG_IP_ROUTE_CLASSID
 108        __u32                   nh_tclassid;
 109#endif
 110        __be32                  nh_saddr;
 111        int                     nh_saddr_genid;
 112#define fib_nh_family           nh_common.nhc_family
 113#define fib_nh_dev              nh_common.nhc_dev
 114#define fib_nh_oif              nh_common.nhc_oif
 115#define fib_nh_flags            nh_common.nhc_flags
 116#define fib_nh_lws              nh_common.nhc_lwtstate
 117#define fib_nh_scope            nh_common.nhc_scope
 118#define fib_nh_gw_family        nh_common.nhc_gw_family
 119#define fib_nh_gw4              nh_common.nhc_gw.ipv4
 120#define fib_nh_gw6              nh_common.nhc_gw.ipv6
 121#define fib_nh_weight           nh_common.nhc_weight
 122#define fib_nh_upper_bound      nh_common.nhc_upper_bound
 123};
 124
 125/*
 126 * This structure contains data shared by many of routes.
 127 */
 128
 129struct nexthop;
 130
 131struct fib_info {
 132        struct hlist_node       fib_hash;
 133        struct hlist_node       fib_lhash;
 134        struct list_head        nh_list;
 135        struct net              *fib_net;
 136        int                     fib_treeref;
 137        refcount_t              fib_clntref;
 138        unsigned int            fib_flags;
 139        unsigned char           fib_dead;
 140        unsigned char           fib_protocol;
 141        unsigned char           fib_scope;
 142        unsigned char           fib_type;
 143        __be32                  fib_prefsrc;
 144        u32                     fib_tb_id;
 145        u32                     fib_priority;
 146        struct dst_metrics      *fib_metrics;
 147#define fib_mtu fib_metrics->metrics[RTAX_MTU-1]
 148#define fib_window fib_metrics->metrics[RTAX_WINDOW-1]
 149#define fib_rtt fib_metrics->metrics[RTAX_RTT-1]
 150#define fib_advmss fib_metrics->metrics[RTAX_ADVMSS-1]
 151        int                     fib_nhs;
 152        bool                    fib_nh_is_v6;
 153        bool                    nh_updated;
 154        struct nexthop          *nh;
 155        struct rcu_head         rcu;
 156        struct fib_nh           fib_nh[0];
 157};
 158
 159
 160#ifdef CONFIG_IP_MULTIPLE_TABLES
 161struct fib_rule;
 162#endif
 163
 164struct fib_table;
 165struct fib_result {
 166        __be32                  prefix;
 167        unsigned char           prefixlen;
 168        unsigned char           nh_sel;
 169        unsigned char           type;
 170        unsigned char           scope;
 171        u32                     tclassid;
 172        struct fib_nh_common    *nhc;
 173        struct fib_info         *fi;
 174        struct fib_table        *table;
 175        struct hlist_head       *fa_head;
 176};
 177
 178struct fib_result_nl {
 179        __be32          fl_addr;   /* To be looked up*/
 180        u32             fl_mark;
 181        unsigned char   fl_tos;
 182        unsigned char   fl_scope;
 183        unsigned char   tb_id_in;
 184
 185        unsigned char   tb_id;      /* Results */
 186        unsigned char   prefixlen;
 187        unsigned char   nh_sel;
 188        unsigned char   type;
 189        unsigned char   scope;
 190        int             err;
 191};
 192
 193#ifdef CONFIG_IP_MULTIPLE_TABLES
 194#define FIB_TABLE_HASHSZ 256
 195#else
 196#define FIB_TABLE_HASHSZ 2
 197#endif
 198
 199__be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
 200                                 unsigned char scope);
 201__be32 fib_result_prefsrc(struct net *net, struct fib_result *res);
 202
 203#define FIB_RES_NHC(res)                ((res).nhc)
 204#define FIB_RES_DEV(res)        (FIB_RES_NHC(res)->nhc_dev)
 205#define FIB_RES_OIF(res)        (FIB_RES_NHC(res)->nhc_oif)
 206
 207struct fib_entry_notifier_info {
 208        struct fib_notifier_info info; /* must be first */
 209        u32 dst;
 210        int dst_len;
 211        struct fib_info *fi;
 212        u8 tos;
 213        u8 type;
 214        u32 tb_id;
 215};
 216
 217struct fib_nh_notifier_info {
 218        struct fib_notifier_info info; /* must be first */
 219        struct fib_nh *fib_nh;
 220};
 221
 222int call_fib4_notifier(struct notifier_block *nb, struct net *net,
 223                       enum fib_event_type event_type,
 224                       struct fib_notifier_info *info);
 225int call_fib4_notifiers(struct net *net, enum fib_event_type event_type,
 226                        struct fib_notifier_info *info);
 227
 228int __net_init fib4_notifier_init(struct net *net);
 229void __net_exit fib4_notifier_exit(struct net *net);
 230
 231void fib_info_notify_update(struct net *net, struct nl_info *info);
 232void fib_notify(struct net *net, struct notifier_block *nb);
 233
 234struct fib_table {
 235        struct hlist_node       tb_hlist;
 236        u32                     tb_id;
 237        int                     tb_num_default;
 238        struct rcu_head         rcu;
 239        unsigned long           *tb_data;
 240        unsigned long           __data[0];
 241};
 242
 243struct fib_dump_filter {
 244        u32                     table_id;
 245        /* filter_set is an optimization that an entry is set */
 246        bool                    filter_set;
 247        bool                    dump_all_families;
 248        bool                    dump_routes;
 249        bool                    dump_exceptions;
 250        unsigned char           protocol;
 251        unsigned char           rt_type;
 252        unsigned int            flags;
 253        struct net_device       *dev;
 254};
 255
 256int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 257                     struct fib_result *res, int fib_flags);
 258int fib_table_insert(struct net *, struct fib_table *, struct fib_config *,
 259                     struct netlink_ext_ack *extack);
 260int fib_table_delete(struct net *, struct fib_table *, struct fib_config *,
 261                     struct netlink_ext_ack *extack);
 262int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
 263                   struct netlink_callback *cb, struct fib_dump_filter *filter);
 264int fib_table_flush(struct net *net, struct fib_table *table, bool flush_all);
 265struct fib_table *fib_trie_unmerge(struct fib_table *main_tb);
 266void fib_table_flush_external(struct fib_table *table);
 267void fib_free_table(struct fib_table *tb);
 268
 269#ifndef CONFIG_IP_MULTIPLE_TABLES
 270
 271#define TABLE_LOCAL_INDEX       (RT_TABLE_LOCAL & (FIB_TABLE_HASHSZ - 1))
 272#define TABLE_MAIN_INDEX        (RT_TABLE_MAIN  & (FIB_TABLE_HASHSZ - 1))
 273
 274static inline struct fib_table *fib_get_table(struct net *net, u32 id)
 275{
 276        struct hlist_node *tb_hlist;
 277        struct hlist_head *ptr;
 278
 279        ptr = id == RT_TABLE_LOCAL ?
 280                &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX] :
 281                &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX];
 282
 283        tb_hlist = rcu_dereference_rtnl(hlist_first_rcu(ptr));
 284
 285        return hlist_entry(tb_hlist, struct fib_table, tb_hlist);
 286}
 287
 288static inline struct fib_table *fib_new_table(struct net *net, u32 id)
 289{
 290        return fib_get_table(net, id);
 291}
 292
 293static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
 294                             struct fib_result *res, unsigned int flags)
 295{
 296        struct fib_table *tb;
 297        int err = -ENETUNREACH;
 298
 299        rcu_read_lock();
 300
 301        tb = fib_get_table(net, RT_TABLE_MAIN);
 302        if (tb)
 303                err = fib_table_lookup(tb, flp, res, flags | FIB_LOOKUP_NOREF);
 304
 305        if (err == -EAGAIN)
 306                err = -ENETUNREACH;
 307
 308        rcu_read_unlock();
 309
 310        return err;
 311}
 312
 313static inline bool fib4_rule_default(const struct fib_rule *rule)
 314{
 315        return true;
 316}
 317
 318static inline int fib4_rules_dump(struct net *net, struct notifier_block *nb)
 319{
 320        return 0;
 321}
 322
 323static inline unsigned int fib4_rules_seq_read(struct net *net)
 324{
 325        return 0;
 326}
 327
 328static inline bool fib4_rules_early_flow_dissect(struct net *net,
 329                                                 struct sk_buff *skb,
 330                                                 struct flowi4 *fl4,
 331                                                 struct flow_keys *flkeys)
 332{
 333        return false;
 334}
 335#else /* CONFIG_IP_MULTIPLE_TABLES */
 336int __net_init fib4_rules_init(struct net *net);
 337void __net_exit fib4_rules_exit(struct net *net);
 338
 339struct fib_table *fib_new_table(struct net *net, u32 id);
 340struct fib_table *fib_get_table(struct net *net, u32 id);
 341
 342int __fib_lookup(struct net *net, struct flowi4 *flp,
 343                 struct fib_result *res, unsigned int flags);
 344
 345static inline int fib_lookup(struct net *net, struct flowi4 *flp,
 346                             struct fib_result *res, unsigned int flags)
 347{
 348        struct fib_table *tb;
 349        int err = -ENETUNREACH;
 350
 351        flags |= FIB_LOOKUP_NOREF;
 352        if (net->ipv4.fib_has_custom_rules)
 353                return __fib_lookup(net, flp, res, flags);
 354
 355        rcu_read_lock();
 356
 357        res->tclassid = 0;
 358
 359        tb = rcu_dereference_rtnl(net->ipv4.fib_main);
 360        if (tb)
 361                err = fib_table_lookup(tb, flp, res, flags);
 362
 363        if (!err)
 364                goto out;
 365
 366        tb = rcu_dereference_rtnl(net->ipv4.fib_default);
 367        if (tb)
 368                err = fib_table_lookup(tb, flp, res, flags);
 369
 370out:
 371        if (err == -EAGAIN)
 372                err = -ENETUNREACH;
 373
 374        rcu_read_unlock();
 375
 376        return err;
 377}
 378
 379bool fib4_rule_default(const struct fib_rule *rule);
 380int fib4_rules_dump(struct net *net, struct notifier_block *nb);
 381unsigned int fib4_rules_seq_read(struct net *net);
 382
 383static inline bool fib4_rules_early_flow_dissect(struct net *net,
 384                                                 struct sk_buff *skb,
 385                                                 struct flowi4 *fl4,
 386                                                 struct flow_keys *flkeys)
 387{
 388        unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
 389
 390        if (!net->ipv4.fib_rules_require_fldissect)
 391                return false;
 392
 393        skb_flow_dissect_flow_keys(skb, flkeys, flag);
 394        fl4->fl4_sport = flkeys->ports.src;
 395        fl4->fl4_dport = flkeys->ports.dst;
 396        fl4->flowi4_proto = flkeys->basic.ip_proto;
 397
 398        return true;
 399}
 400
 401#endif /* CONFIG_IP_MULTIPLE_TABLES */
 402
 403/* Exported by fib_frontend.c */
 404extern const struct nla_policy rtm_ipv4_policy[];
 405void ip_fib_init(void);
 406int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
 407                    struct netlink_ext_ack *extack);
 408__be32 fib_compute_spec_dst(struct sk_buff *skb);
 409bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev);
 410int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 411                        u8 tos, int oif, struct net_device *dev,
 412                        struct in_device *idev, u32 *itag);
 413#ifdef CONFIG_IP_ROUTE_CLASSID
 414static inline int fib_num_tclassid_users(struct net *net)
 415{
 416        return net->ipv4.fib_num_tclassid_users;
 417}
 418#else
 419static inline int fib_num_tclassid_users(struct net *net)
 420{
 421        return 0;
 422}
 423#endif
 424int fib_unmerge(struct net *net);
 425
 426/* Exported by fib_semantics.c */
 427int ip_fib_check_default(__be32 gw, struct net_device *dev);
 428int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force);
 429int fib_sync_down_addr(struct net_device *dev, __be32 local);
 430int fib_sync_up(struct net_device *dev, unsigned char nh_flags);
 431void fib_sync_mtu(struct net_device *dev, u32 orig_mtu);
 432void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig);
 433
 434#ifdef CONFIG_IP_ROUTE_MULTIPATH
 435int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
 436                       const struct sk_buff *skb, struct flow_keys *flkeys);
 437#endif
 438int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
 439                 struct netlink_ext_ack *extack);
 440void fib_select_multipath(struct fib_result *res, int hash);
 441void fib_select_path(struct net *net, struct fib_result *res,
 442                     struct flowi4 *fl4, const struct sk_buff *skb);
 443
 444int fib_nh_init(struct net *net, struct fib_nh *fib_nh,
 445                struct fib_config *cfg, int nh_weight,
 446                struct netlink_ext_ack *extack);
 447void fib_nh_release(struct net *net, struct fib_nh *fib_nh);
 448int fib_nh_common_init(struct fib_nh_common *nhc, struct nlattr *fc_encap,
 449                       u16 fc_encap_type, void *cfg, gfp_t gfp_flags,
 450                       struct netlink_ext_ack *extack);
 451void fib_nh_common_release(struct fib_nh_common *nhc);
 452
 453/* Exported by fib_trie.c */
 454void fib_trie_init(void);
 455struct fib_table *fib_trie_table(u32 id, struct fib_table *alias);
 456
 457static inline void fib_combine_itag(u32 *itag, const struct fib_result *res)
 458{
 459#ifdef CONFIG_IP_ROUTE_CLASSID
 460        struct fib_nh_common *nhc = res->nhc;
 461#ifdef CONFIG_IP_MULTIPLE_TABLES
 462        u32 rtag;
 463#endif
 464        if (nhc->nhc_family == AF_INET) {
 465                struct fib_nh *nh;
 466
 467                nh = container_of(nhc, struct fib_nh, nh_common);
 468                *itag = nh->nh_tclassid << 16;
 469        } else {
 470                *itag = 0;
 471        }
 472
 473#ifdef CONFIG_IP_MULTIPLE_TABLES
 474        rtag = res->tclassid;
 475        if (*itag == 0)
 476                *itag = (rtag<<16);
 477        *itag |= (rtag>>16);
 478#endif
 479#endif
 480}
 481
 482void fib_flush(struct net *net);
 483void free_fib_info(struct fib_info *fi);
 484
 485static inline void fib_info_hold(struct fib_info *fi)
 486{
 487        refcount_inc(&fi->fib_clntref);
 488}
 489
 490static inline void fib_info_put(struct fib_info *fi)
 491{
 492        if (refcount_dec_and_test(&fi->fib_clntref))
 493                free_fib_info(fi);
 494}
 495
 496#ifdef CONFIG_PROC_FS
 497int __net_init fib_proc_init(struct net *net);
 498void __net_exit fib_proc_exit(struct net *net);
 499#else
 500static inline int fib_proc_init(struct net *net)
 501{
 502        return 0;
 503}
 504static inline void fib_proc_exit(struct net *net)
 505{
 506}
 507#endif
 508
 509u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr);
 510
 511int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
 512                          struct fib_dump_filter *filter,
 513                          struct netlink_callback *cb);
 514
 515int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nh,
 516                     u8 rt_family, unsigned char *flags, bool skip_oif);
 517int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nh,
 518                    int nh_weight, u8 rt_family);
 519#endif  /* _NET_FIB_H */
 520