include/net/ip6_fib.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  */
   8
   9 #ifndef _IP6_FIB_H
  10 #define _IP6_FIB_H
  11
  12 #include <linux/ipv6_route.h>
  13 #include <linux/rtnetlink.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/notifier.h>
  16 #include <net/dst.h>
  17 #include <net/flow.h>
  18 #include <net/ip_fib.h>
  19 #include <net/netlink.h>
  20 #include <net/inetpeer.h>
  21 #include <net/fib_notifier.h>
  22 #include <linux/indirect_call_wrapper.h>
  23
  24 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
  25 #define FIB6_TABLE_HASHSZ 256
  26 #else
  27 #define FIB6_TABLE_HASHSZ 1
  28 #endif
  29
  30 #define RT6_DEBUG 2
  31
  32 #if RT6_DEBUG >= 3
  33 #define RT6_TRACE(x...) pr_debug(x)
  34 #else
  35 #define RT6_TRACE(x...) do { ; } while (0)
  36 #endif
  37
  38 struct rt6_info;
  39 struct fib6_info;
  40
  41 struct fib6_config {
  42         u32             fc_table;
  43         u32             fc_metric;
  44         int             fc_dst_len;
  45         int             fc_src_len;
  46         int             fc_ifindex;
  47         u32             fc_flags;
  48         u32             fc_protocol;
  49         u16             fc_type;        /* only 8 bits are used */
  50         u16             fc_delete_all_nh : 1,
  51                         fc_ignore_dev_down:1,
  52                         __unused : 14;
  53         u32             fc_nh_id;
  54
  55         struct in6_addr fc_dst;
  56         struct in6_addr fc_src;
  57         struct in6_addr fc_prefsrc;
  58         struct in6_addr fc_gateway;
  59
  60         unsigned long   fc_expires;
  61         struct nlattr   *fc_mx;
  62         int             fc_mx_len;
  63         int             fc_mp_len;
  64         struct nlattr   *fc_mp;
  65
  66         struct nl_info  fc_nlinfo;
  67         struct nlattr   *fc_encap;
  68         u16             fc_encap_type;
  69         bool            fc_is_fdb;
  70 };
  71
  72 struct fib6_node {
  73         struct fib6_node __rcu  *parent;
  74         struct fib6_node __rcu  *left;
  75         struct fib6_node __rcu  *right;
  76 #ifdef CONFIG_IPV6_SUBTREES
  77         struct fib6_node __rcu  *subtree;
  78 #endif
  79         struct fib6_info __rcu  *leaf;
  80
  81         __u16                   fn_bit;         /* bit key */
  82         __u16                   fn_flags;
  83         int                     fn_sernum;
  84         struct fib6_info __rcu  *rr_ptr;
  85         struct rcu_head         rcu;
  86 };
  87
  88 struct fib6_gc_args {
  89         int                     timeout;
  90         int                     more;
  91 };
  92
  93 #ifndef CONFIG_IPV6_SUBTREES
  94 #define FIB6_SUBTREE(fn)        NULL
  95
  96 static inline bool fib6_routes_require_src(const struct net *net)
  97 {
  98         return false;
  99 }
 100
 101 static inline void fib6_routes_require_src_inc(struct net *net) {}
 102 static inline void fib6_routes_require_src_dec(struct net *net) {}
 103
 104 #else
 105
 106 static inline bool fib6_routes_require_src(const struct net *net)
 107 {
 108         return net->ipv6.fib6_routes_require_src > 0;
 109 }
 110
 111 static inline void fib6_routes_require_src_inc(struct net *net)
 112 {
 113         net->ipv6.fib6_routes_require_src++;
 114 }
 115
 116 static inline void fib6_routes_require_src_dec(struct net *net)
 117 {
 118         net->ipv6.fib6_routes_require_src--;
 119 }
 120
 121 #define FIB6_SUBTREE(fn)        (rcu_dereference_protected((fn)->subtree, 1))
 122 #endif
 123
 124 /*
 125  *      routing information
 126  *
 127  */
 128
 129 struct rt6key {
 130         struct in6_addr addr;
 131         int             plen;
 132 };
 133
 134 struct fib6_table;
 135
 136 struct rt6_exception_bucket {
 137         struct hlist_head       chain;
 138         int                     depth;
 139 };
 140
 141 struct rt6_exception {
 142         struct hlist_node       hlist;
 143         struct rt6_info         *rt6i;
 144         unsigned long           stamp;
 145         struct rcu_head         rcu;
 146 };
 147
 148 #define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10
 149 #define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT)
 150 #define FIB6_MAX_DEPTH 5
 151
 152 struct fib6_nh {
 153         struct fib_nh_common    nh_common;
 154
 155 #ifdef CONFIG_IPV6_ROUTER_PREF
 156         unsigned long           last_probe;
 157 #endif
 158
 159         struct rt6_info * __percpu *rt6i_pcpu;
 160         struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
 161 };
 162
 163 struct fib6_info {
 164         struct fib6_table               *fib6_table;
 165         struct fib6_info __rcu          *fib6_next;
 166         struct fib6_node __rcu          *fib6_node;
 167
 168         /* Multipath routes:
 169          * siblings is a list of fib6_info that have the same metric/weight,
 170          * destination, but not the same gateway. nsiblings is just a cache
 171          * to speed up lookup.
 172          */
 173         union {
 174                 struct list_head        fib6_siblings;
 175                 struct list_head        nh_list;
 176         };
 177         unsigned int                    fib6_nsiblings;
 178
 179         refcount_t                      fib6_ref;
 180         unsigned long                   expires;
 181         struct dst_metrics              *fib6_metrics;
 182 #define fib6_pmtu               fib6_metrics->metrics[RTAX_MTU-1]
 183
 184         struct rt6key                   fib6_dst;
 185         u32                             fib6_flags;
 186         struct rt6key                   fib6_src;
 187         struct rt6key                   fib6_prefsrc;
 188
 189         u32                             fib6_metric;
 190         u8                              fib6_protocol;
 191         u8                              fib6_type;
 192         u8                              should_flush:1,
 193                                         dst_nocount:1,
 194                                         dst_nopolicy:1,
 195                                         fib6_destroying:1,
 196                                         offload:1,
 197                                         trap:1,
 198                                         unused:2;
 199
 200         struct rcu_head                 rcu;
 201         struct nexthop                  *nh;
 202         struct fib6_nh                  fib6_nh[];
 203 };
 204
 205 struct rt6_info {
 206         struct dst_entry                dst;
 207         struct fib6_info __rcu          *from;
 208         int                             sernum;
 209
 210         struct rt6key                   rt6i_dst;
 211         struct rt6key                   rt6i_src;
 212         struct in6_addr                 rt6i_gateway;
 213         struct inet6_dev                *rt6i_idev;
 214         u32                             rt6i_flags;
 215
 216         struct list_head                rt6i_uncached;
 217         struct uncached_list            *rt6i_uncached_list;
 218
 219         /* more non-fragment space at head required */
 220         unsigned short                  rt6i_nfheader_len;
 221 };
 222
 223 struct fib6_result {
 224         struct fib6_nh          *nh;
 225         struct fib6_info        *f6i;
 226         u32                     fib6_flags;
 227         u8                      fib6_type;
 228         struct rt6_info         *rt6;
 229 };
 230
 231 #define for_each_fib6_node_rt_rcu(fn)                                   \
 232         for (rt = rcu_dereference((fn)->leaf); rt;                      \
 233              rt = rcu_dereference(rt->fib6_next))
 234
 235 #define for_each_fib6_walker_rt(w)                                      \
 236         for (rt = (w)->leaf; rt;                                        \
 237              rt = rcu_dereference_protected(rt->fib6_next, 1))
 238
 239 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 240 {
 241         return ((struct rt6_info *)dst)->rt6i_idev;
 242 }
 243
 244 static inline bool fib6_requires_src(const struct fib6_info *rt)
 245 {
 246         return rt->fib6_src.plen > 0;
 247 }
 248
 249 static inline void fib6_clean_expires(struct fib6_info *f6i)
 250 {
 251         f6i->fib6_flags &= ~RTF_EXPIRES;
 252         f6i->expires = 0;
 253 }
 254
 255 static inline void fib6_set_expires(struct fib6_info *f6i,
 256                                     unsigned long expires)
 257 {
 258         f6i->expires = expires;
 259         f6i->fib6_flags |= RTF_EXPIRES;
 260 }
 261
 262 static inline bool fib6_check_expired(const struct fib6_info *f6i)
 263 {
 264         if (f6i->fib6_flags & RTF_EXPIRES)
 265                 return time_after(jiffies, f6i->expires);
 266         return false;
 267 }
 268
 269 /* Function to safely get fn->sernum for passed in rt
 270  * and store result in passed in cookie.
 271  * Return true if we can get cookie safely
 272  * Return false if not
 273  */
 274 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 275                                         u32 *cookie)
 276 {
 277         struct fib6_node *fn;
 278         bool status = false;
 279
 280         fn = rcu_dereference(f6i->fib6_node);
 281
 282         if (fn) {
 283                 *cookie = fn->fn_sernum;
 284                 /* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
 285                 smp_rmb();
 286                 status = true;
 287         }
 288
 289         return status;
 290 }
 291
 292 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 293 {
 294         struct fib6_info *from;
 295         u32 cookie = 0;
 296
 297         if (rt->sernum)
 298                 return rt->sernum;
 299
 300         rcu_read_lock();
 301
 302         from = rcu_dereference(rt->from);
 303         if (from)
 304                 fib6_get_cookie_safe(from, &cookie);
 305
 306         rcu_read_unlock();
 307
 308         return cookie;
 309 }
 310
 311 static inline void ip6_rt_put(struct rt6_info *rt)
 312 {
 313         /* dst_release() accepts a NULL parameter.
 314          * We rely on dst being first structure in struct rt6_info
 315          */
 316         BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
 317         dst_release(&rt->dst);
 318 }
 319
 320 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh);
 321 void fib6_info_destroy_rcu(struct rcu_head *head);
 322
 323 static inline void fib6_info_hold(struct fib6_info *f6i)
 324 {
 325         refcount_inc(&f6i->fib6_ref);
 326 }
 327
 328 static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
 329 {
 330         return refcount_inc_not_zero(&f6i->fib6_ref);
 331 }
 332
 333 static inline void fib6_info_release(struct fib6_info *f6i)
 334 {
 335         if (f6i && refcount_dec_and_test(&f6i->fib6_ref))
 336                 call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
 337 }
 338
 339 static inline void fib6_info_hw_flags_set(struct fib6_info *f6i, bool offload,
 340                                           bool trap)
 341 {
 342         f6i->offload = offload;
 343         f6i->trap = trap;
 344 }
 345
 346 enum fib6_walk_state {
 347 #ifdef CONFIG_IPV6_SUBTREES
 348         FWS_S,
 349 #endif
 350         FWS_L,
 351         FWS_R,
 352         FWS_C,
 353         FWS_U
 354 };
 355
 356 struct fib6_walker {
 357         struct list_head lh;
 358         struct fib6_node *root, *node;
 359         struct fib6_info *leaf;
 360         enum fib6_walk_state state;
 361         unsigned int skip;
 362         unsigned int count;
 363         unsigned int skip_in_node;
 364         int (*func)(struct fib6_walker *);
 365         void *args;
 366 };
 367
 368 struct rt6_statistics {
 369         __u32           fib_nodes;              /* all fib6 nodes */
 370         __u32           fib_route_nodes;        /* intermediate nodes */
 371         __u32           fib_rt_entries;         /* rt entries in fib table */
 372         __u32           fib_rt_cache;           /* cached rt entries in exception table */
 373         __u32           fib_discarded_routes;   /* total number of routes delete */
 374
 375         /* The following stats are not protected by any lock */
 376         atomic_t        fib_rt_alloc;           /* total number of routes alloced */
 377         atomic_t        fib_rt_uncache;         /* rt entries in uncached list */
 378 };
 379
 380 #define RTN_TL_ROOT     0x0001
 381 #define RTN_ROOT        0x0002          /* tree root node               */
 382 #define RTN_RTINFO      0x0004          /* node with valid routing info */
 383
 384 /*
 385  *      priority levels (or metrics)
 386  *
 387  */
 388
 389
 390 struct fib6_table {
 391         struct hlist_node       tb6_hlist;
 392         u32                     tb6_id;
 393         spinlock_t              tb6_lock;
 394         struct fib6_node        tb6_root;
 395         struct inet_peer_base   tb6_peers;
 396         unsigned int            flags;
 397         unsigned int            fib_seq;
 398 #define RT6_TABLE_HAS_DFLT_ROUTER       BIT(0)
 399 };
 400
 401 #define RT6_TABLE_UNSPEC        RT_TABLE_UNSPEC
 402 #define RT6_TABLE_MAIN          RT_TABLE_MAIN
 403 #define RT6_TABLE_DFLT          RT6_TABLE_MAIN
 404 #define RT6_TABLE_INFO          RT6_TABLE_MAIN
 405 #define RT6_TABLE_PREFIX        RT6_TABLE_MAIN
 406
 407 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 408 #define FIB6_TABLE_MIN          1
 409 #define FIB6_TABLE_MAX          RT_TABLE_MAX
 410 #define RT6_TABLE_LOCAL         RT_TABLE_LOCAL
 411 #else
 412 #define FIB6_TABLE_MIN          RT_TABLE_MAIN
 413 #define FIB6_TABLE_MAX          FIB6_TABLE_MIN
 414 #define RT6_TABLE_LOCAL         RT6_TABLE_MAIN
 415 #endif
 416
 417 typedef struct rt6_info *(*pol_lookup_t)(struct net *,
 418                                          struct fib6_table *,
 419                                          struct flowi6 *,
 420                                          const struct sk_buff *, int);
 421
 422 struct fib6_entry_notifier_info {
 423         struct fib_notifier_info info; /* must be first */
 424         struct fib6_info *rt;
 425         unsigned int nsiblings;
 426 };
 427
 428 /*
 429  *      exported functions
 430  */
 431
 432 struct fib6_table *fib6_get_table(struct net *net, u32 id);
 433 struct fib6_table *fib6_new_table(struct net *net, u32 id);
 434 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 435                                    const struct sk_buff *skb,
 436                                    int flags, pol_lookup_t lookup);
 437
 438 /* called with rcu lock held; can return error pointer
 439  * caller needs to select path
 440  */
 441 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 442                 struct fib6_result *res, int flags);
 443
 444 /* called with rcu lock held; caller needs to select path */
 445 int fib6_table_lookup(struct net *net, struct fib6_table *table,
 446                       int oif, struct flowi6 *fl6, struct fib6_result *res,
 447                       int strict);
 448
 449 void fib6_select_path(const struct net *net, struct fib6_result *res,
 450                       struct flowi6 *fl6, int oif, bool have_oif_match,
 451                       const struct sk_buff *skb, int strict);
 452 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
 453                                    const struct in6_addr *daddr,
 454                                    const struct in6_addr *saddr);
 455
 456 struct fib6_node *fib6_locate(struct fib6_node *root,
 457                               const struct in6_addr *daddr, int dst_len,
 458                               const struct in6_addr *saddr, int src_len,
 459                               bool exact_match);
 460
 461 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
 462                     void *arg);
 463 void fib6_clean_all_skip_notify(struct net *net,
 464                                 int (*func)(struct fib6_info *, void *arg),
 465                                 void *arg);
 466
 467 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 468              struct nl_info *info, struct netlink_ext_ack *extack);
 469 int fib6_del(struct fib6_info *rt, struct nl_info *info);
 470
 471 static inline
 472 void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
 473 {
 474         const struct fib6_info *from;
 475
 476         rcu_read_lock();
 477
 478         from = rcu_dereference(rt->from);
 479         if (from) {
 480                 *addr = from->fib6_prefsrc.addr;
 481         } else {
 482                 struct in6_addr in6_zero = {};
 483
 484                 *addr = in6_zero;
 485         }
 486
 487         rcu_read_unlock();
 488 }
 489
 490 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
 491                  struct fib6_config *cfg, gfp_t gfp_flags,
 492                  struct netlink_ext_ack *extack);
 493 void fib6_nh_release(struct fib6_nh *fib6_nh);
 494
 495 int call_fib6_entry_notifiers(struct net *net,
 496                               enum fib_event_type event_type,
 497                               struct fib6_info *rt,
 498                               struct netlink_ext_ack *extack);
 499 int call_fib6_multipath_entry_notifiers(struct net *net,
 500                                         enum fib_event_type event_type,
 501                                         struct fib6_info *rt,
 502                                         unsigned int nsiblings,
 503                                         struct netlink_ext_ack *extack);
 504 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt);
 505 void fib6_rt_update(struct net *net, struct fib6_info *rt,
 506                     struct nl_info *info);
 507 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
 508                      unsigned int flags);
 509
 510 void fib6_run_gc(unsigned long expires, struct net *net, bool force);
 511
 512 void fib6_gc_cleanup(void);
 513
 514 int fib6_init(void);
 515
 516 struct ipv6_route_iter {
 517         struct seq_net_private p;
 518         struct fib6_walker w;
 519         loff_t skip;
 520         struct fib6_table *tbl;
 521         int sernum;
 522 };
 523
 524 extern const struct seq_operations ipv6_route_seq_ops;
 525
 526 int call_fib6_notifier(struct notifier_block *nb,
 527                        enum fib_event_type event_type,
 528                        struct fib_notifier_info *info);
 529 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
 530                         struct fib_notifier_info *info);
 531
 532 int __net_init fib6_notifier_init(struct net *net);
 533 void __net_exit fib6_notifier_exit(struct net *net);
 534
 535 unsigned int fib6_tables_seq_read(struct net *net);
 536 int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 537                      struct netlink_ext_ack *extack);
 538
 539 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
 540 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
 541 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i);
 542
 543 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 544 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
 545 {
 546         return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
 547 }
 548
 549 #if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
 550 struct bpf_iter__ipv6_route {
 551         __bpf_md_ptr(struct bpf_iter_meta *, meta);
 552         __bpf_md_ptr(struct fib6_info *, rt);
 553 };
 554 #endif
 555
 556 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_output(struct net *net,
 557                                              struct fib6_table *table,
 558                                              struct flowi6 *fl6,
 559                                              const struct sk_buff *skb,
 560                                              int flags));
 561 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_input(struct net *net,
 562                                              struct fib6_table *table,
 563                                              struct flowi6 *fl6,
 564                                              const struct sk_buff *skb,
 565                                              int flags));
 566 INDIRECT_CALLABLE_DECLARE(struct rt6_info *__ip6_route_redirect(struct net *net,
 567                                              struct fib6_table *table,
 568                                              struct flowi6 *fl6,
 569                                              const struct sk_buff *skb,
 570                                              int flags));
 571 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_lookup(struct net *net,
 572                                              struct fib6_table *table,
 573                                              struct flowi6 *fl6,
 574                                              const struct sk_buff *skb,
 575                                              int flags));
 576 static inline struct rt6_info *pol_lookup_func(pol_lookup_t lookup,
 577                                                 struct net *net,
 578                                                 struct fib6_table *table,
 579                                                 struct flowi6 *fl6,
 580                                                 const struct sk_buff *skb,
 581                                                 int flags)
 582 {
 583         return INDIRECT_CALL_4(lookup,
 584                                ip6_pol_route_output,
 585                                ip6_pol_route_input,
 586                                ip6_pol_route_lookup,
 587                                __ip6_route_redirect,
 588                                net, table, fl6, skb, flags);
 589 }
 590
 591 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 592 static inline bool fib6_has_custom_rules(const struct net *net)
 593 {
 594         return net->ipv6.fib6_has_custom_rules;
 595 }
 596
 597 int fib6_rules_init(void);
 598 void fib6_rules_cleanup(void);
 599 bool fib6_rule_default(const struct fib_rule *rule);
 600 int fib6_rules_dump(struct net *net, struct notifier_block *nb,
 601                     struct netlink_ext_ack *extack);
 602 unsigned int fib6_rules_seq_read(struct net *net);
 603
 604 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 605                                                  struct sk_buff *skb,
 606                                                  struct flowi6 *fl6,
 607                                                  struct flow_keys *flkeys)
 608 {
 609         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
 610
 611         if (!net->ipv6.fib6_rules_require_fldissect)
 612                 return false;
 613
 614         skb_flow_dissect_flow_keys(skb, flkeys, flag);
 615         fl6->fl6_sport = flkeys->ports.src;
 616         fl6->fl6_dport = flkeys->ports.dst;
 617         fl6->flowi6_proto = flkeys->basic.ip_proto;
 618
 619         return true;
 620 }
 621 #else
 622 static inline bool fib6_has_custom_rules(const struct net *net)
 623 {
 624         return false;
 625 }
 626 static inline int               fib6_rules_init(void)
 627 {
 628         return 0;
 629 }
 630 static inline void              fib6_rules_cleanup(void)
 631 {
 632         return ;
 633 }
 634 static inline bool fib6_rule_default(const struct fib_rule *rule)
 635 {
 636         return true;
 637 }
 638 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb,
 639                                   struct netlink_ext_ack *extack)
 640 {
 641         return 0;
 642 }
 643 static inline unsigned int fib6_rules_seq_read(struct net *net)
 644 {
 645         return 0;
 646 }
 647 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 648                                                  struct sk_buff *skb,
 649                                                  struct flowi6 *fl6,
 650                                                  struct flow_keys *flkeys)
 651 {
 652         return false;
 653 }
 654 #endif
 655 #endif