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