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