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
 207         struct rt6key                   rt6i_dst;
 208         struct rt6key                   rt6i_src;
 209         struct in6_addr                 rt6i_gateway;
 210         struct inet6_dev                *rt6i_idev;
 211         u32                             rt6i_flags;
 212
 213         struct list_head                rt6i_uncached;
 214         struct uncached_list            *rt6i_uncached_list;
 215
 216         /* more non-fragment space at head required */
 217         unsigned short                  rt6i_nfheader_len;
 218 };
 219
 220 struct fib6_result {
 221         struct fib6_nh          *nh;
 222         struct fib6_info        *f6i;
 223         u32                     fib6_flags;
 224         u8                      fib6_type;
 225         struct rt6_info         *rt6;
 226 };
 227
 228 #define for_each_fib6_node_rt_rcu(fn)                                   \
 229         for (rt = rcu_dereference((fn)->leaf); rt;                      \
 230              rt = rcu_dereference(rt->fib6_next))
 231
 232 #define for_each_fib6_walker_rt(w)                                      \
 233         for (rt = (w)->leaf; rt;                                        \
 234              rt = rcu_dereference_protected(rt->fib6_next, 1))
 235
 236 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 237 {
 238         return ((struct rt6_info *)dst)->rt6i_idev;
 239 }
 240
 241 static inline bool fib6_requires_src(const struct fib6_info *rt)
 242 {
 243         return rt->fib6_src.plen > 0;
 244 }
 245
 246 static inline void fib6_clean_expires(struct fib6_info *f6i)
 247 {
 248         f6i->fib6_flags &= ~RTF_EXPIRES;
 249         f6i->expires = 0;
 250 }
 251
 252 static inline void fib6_set_expires(struct fib6_info *f6i,
 253                                     unsigned long expires)
 254 {
 255         f6i->expires = expires;
 256         f6i->fib6_flags |= RTF_EXPIRES;
 257 }
 258
 259 static inline bool fib6_check_expired(const struct fib6_info *f6i)
 260 {
 261         if (f6i->fib6_flags & RTF_EXPIRES)
 262                 return time_after(jiffies, f6i->expires);
 263         return false;
 264 }
 265
 266 /* Function to safely get fn->sernum for passed in rt
 267  * and store result in passed in cookie.
 268  * Return true if we can get cookie safely
 269  * Return false if not
 270  */
 271 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 272                                         u32 *cookie)
 273 {
 274         struct fib6_node *fn;
 275         bool status = false;
 276
 277         fn = rcu_dereference(f6i->fib6_node);
 278
 279         if (fn) {
 280                 *cookie = fn->fn_sernum;
 281                 /* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
 282                 smp_rmb();
 283                 status = true;
 284         }
 285
 286         return status;
 287 }
 288
 289 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 290 {
 291         struct fib6_info *from;
 292         u32 cookie = 0;
 293
 294         rcu_read_lock();
 295
 296         from = rcu_dereference(rt->from);
 297         if (from)
 298                 fib6_get_cookie_safe(from, &cookie);
 299
 300         rcu_read_unlock();
 301
 302         return cookie;
 303 }
 304
 305 static inline void ip6_rt_put(struct rt6_info *rt)
 306 {
 307         /* dst_release() accepts a NULL parameter.
 308          * We rely on dst being first structure in struct rt6_info
 309          */
 310         BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
 311         dst_release(&rt->dst);
 312 }
 313
 314 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh);
 315 void fib6_info_destroy_rcu(struct rcu_head *head);
 316
 317 static inline void fib6_info_hold(struct fib6_info *f6i)
 318 {
 319         refcount_inc(&f6i->fib6_ref);
 320 }
 321
 322 static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
 323 {
 324         return refcount_inc_not_zero(&f6i->fib6_ref);
 325 }
 326
 327 static inline void fib6_info_release(struct fib6_info *f6i)
 328 {
 329         if (f6i && refcount_dec_and_test(&f6i->fib6_ref))
 330                 call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
 331 }
 332
 333 static inline void fib6_info_hw_flags_set(struct fib6_info *f6i, bool offload,
 334                                           bool trap)
 335 {
 336         f6i->offload = offload;
 337         f6i->trap = trap;
 338 }
 339
 340 enum fib6_walk_state {
 341 #ifdef CONFIG_IPV6_SUBTREES
 342         FWS_S,
 343 #endif
 344         FWS_L,
 345         FWS_R,
 346         FWS_C,
 347         FWS_U
 348 };
 349
 350 struct fib6_walker {
 351         struct list_head lh;
 352         struct fib6_node *root, *node;
 353         struct fib6_info *leaf;
 354         enum fib6_walk_state state;
 355         unsigned int skip;
 356         unsigned int count;
 357         unsigned int skip_in_node;
 358         int (*func)(struct fib6_walker *);
 359         void *args;
 360 };
 361
 362 struct rt6_statistics {
 363         __u32           fib_nodes;              /* all fib6 nodes */
 364         __u32           fib_route_nodes;        /* intermediate nodes */
 365         __u32           fib_rt_entries;         /* rt entries in fib table */
 366         __u32           fib_rt_cache;           /* cached rt entries in exception table */
 367         __u32           fib_discarded_routes;   /* total number of routes delete */
 368
 369         /* The following stats are not protected by any lock */
 370         atomic_t        fib_rt_alloc;           /* total number of routes alloced */
 371         atomic_t        fib_rt_uncache;         /* rt entries in uncached list */
 372 };
 373
 374 #define RTN_TL_ROOT     0x0001
 375 #define RTN_ROOT        0x0002          /* tree root node               */
 376 #define RTN_RTINFO      0x0004          /* node with valid routing info */
 377
 378 /*
 379  *      priority levels (or metrics)
 380  *
 381  */
 382
 383
 384 struct fib6_table {
 385         struct hlist_node       tb6_hlist;
 386         u32                     tb6_id;
 387         spinlock_t              tb6_lock;
 388         struct fib6_node        tb6_root;
 389         struct inet_peer_base   tb6_peers;
 390         unsigned int            flags;
 391         unsigned int            fib_seq;
 392 #define RT6_TABLE_HAS_DFLT_ROUTER       BIT(0)
 393 };
 394
 395 #define RT6_TABLE_UNSPEC        RT_TABLE_UNSPEC
 396 #define RT6_TABLE_MAIN          RT_TABLE_MAIN
 397 #define RT6_TABLE_DFLT          RT6_TABLE_MAIN
 398 #define RT6_TABLE_INFO          RT6_TABLE_MAIN
 399 #define RT6_TABLE_PREFIX        RT6_TABLE_MAIN
 400
 401 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 402 #define FIB6_TABLE_MIN          1
 403 #define FIB6_TABLE_MAX          RT_TABLE_MAX
 404 #define RT6_TABLE_LOCAL         RT_TABLE_LOCAL
 405 #else
 406 #define FIB6_TABLE_MIN          RT_TABLE_MAIN
 407 #define FIB6_TABLE_MAX          FIB6_TABLE_MIN
 408 #define RT6_TABLE_LOCAL         RT6_TABLE_MAIN
 409 #endif
 410
 411 typedef struct rt6_info *(*pol_lookup_t)(struct net *,
 412                                          struct fib6_table *,
 413                                          struct flowi6 *,
 414                                          const struct sk_buff *, int);
 415
 416 struct fib6_entry_notifier_info {
 417         struct fib_notifier_info info; /* must be first */
 418         struct fib6_info *rt;
 419         unsigned int nsiblings;
 420 };
 421
 422 /*
 423  *      exported functions
 424  */
 425
 426 struct fib6_table *fib6_get_table(struct net *net, u32 id);
 427 struct fib6_table *fib6_new_table(struct net *net, u32 id);
 428 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 429                                    const struct sk_buff *skb,
 430                                    int flags, pol_lookup_t lookup);
 431
 432 /* called with rcu lock held; can return error pointer
 433  * caller needs to select path
 434  */
 435 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 436                 struct fib6_result *res, int flags);
 437
 438 /* called with rcu lock held; caller needs to select path */
 439 int fib6_table_lookup(struct net *net, struct fib6_table *table,
 440                       int oif, struct flowi6 *fl6, struct fib6_result *res,
 441                       int strict);
 442
 443 void fib6_select_path(const struct net *net, struct fib6_result *res,
 444                       struct flowi6 *fl6, int oif, bool have_oif_match,
 445                       const struct sk_buff *skb, int strict);
 446 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
 447                                    const struct in6_addr *daddr,
 448                                    const struct in6_addr *saddr);
 449
 450 struct fib6_node *fib6_locate(struct fib6_node *root,
 451                               const struct in6_addr *daddr, int dst_len,
 452                               const struct in6_addr *saddr, int src_len,
 453                               bool exact_match);
 454
 455 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
 456                     void *arg);
 457 void fib6_clean_all_skip_notify(struct net *net,
 458                                 int (*func)(struct fib6_info *, void *arg),
 459                                 void *arg);
 460
 461 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 462              struct nl_info *info, struct netlink_ext_ack *extack);
 463 int fib6_del(struct fib6_info *rt, struct nl_info *info);
 464
 465 static inline
 466 void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
 467 {
 468         const struct fib6_info *from;
 469
 470         rcu_read_lock();
 471
 472         from = rcu_dereference(rt->from);
 473         if (from) {
 474                 *addr = from->fib6_prefsrc.addr;
 475         } else {
 476                 struct in6_addr in6_zero = {};
 477
 478                 *addr = in6_zero;
 479         }
 480
 481         rcu_read_unlock();
 482 }
 483
 484 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
 485                  struct fib6_config *cfg, gfp_t gfp_flags,
 486                  struct netlink_ext_ack *extack);
 487 void fib6_nh_release(struct fib6_nh *fib6_nh);
 488
 489 int call_fib6_entry_notifiers(struct net *net,
 490                               enum fib_event_type event_type,
 491                               struct fib6_info *rt,
 492                               struct netlink_ext_ack *extack);
 493 int call_fib6_multipath_entry_notifiers(struct net *net,
 494                                         enum fib_event_type event_type,
 495                                         struct fib6_info *rt,
 496                                         unsigned int nsiblings,
 497                                         struct netlink_ext_ack *extack);
 498 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt);
 499 void fib6_rt_update(struct net *net, struct fib6_info *rt,
 500                     struct nl_info *info);
 501 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
 502                      unsigned int flags);
 503
 504 void fib6_run_gc(unsigned long expires, struct net *net, bool force);
 505
 506 void fib6_gc_cleanup(void);
 507
 508 int fib6_init(void);
 509
 510 struct ipv6_route_iter {
 511         struct seq_net_private p;
 512         struct fib6_walker w;
 513         loff_t skip;
 514         struct fib6_table *tbl;
 515         int sernum;
 516 };
 517
 518 extern const struct seq_operations ipv6_route_seq_ops;
 519
 520 int call_fib6_notifier(struct notifier_block *nb,
 521                        enum fib_event_type event_type,
 522                        struct fib_notifier_info *info);
 523 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
 524                         struct fib_notifier_info *info);
 525
 526 int __net_init fib6_notifier_init(struct net *net);
 527 void __net_exit fib6_notifier_exit(struct net *net);
 528
 529 unsigned int fib6_tables_seq_read(struct net *net);
 530 int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 531                      struct netlink_ext_ack *extack);
 532
 533 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
 534 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
 535 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i);
 536
 537 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 538 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
 539 {
 540         return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
 541 }
 542
 543 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 544 static inline bool fib6_has_custom_rules(const struct net *net)
 545 {
 546         return net->ipv6.fib6_has_custom_rules;
 547 }
 548
 549 int fib6_rules_init(void);
 550 void fib6_rules_cleanup(void);
 551 bool fib6_rule_default(const struct fib_rule *rule);
 552 int fib6_rules_dump(struct net *net, struct notifier_block *nb,
 553                     struct netlink_ext_ack *extack);
 554 unsigned int fib6_rules_seq_read(struct net *net);
 555
 556 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 557                                                  struct sk_buff *skb,
 558                                                  struct flowi6 *fl6,
 559                                                  struct flow_keys *flkeys)
 560 {
 561         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
 562
 563         if (!net->ipv6.fib6_rules_require_fldissect)
 564                 return false;
 565
 566         skb_flow_dissect_flow_keys(skb, flkeys, flag);
 567         fl6->fl6_sport = flkeys->ports.src;
 568         fl6->fl6_dport = flkeys->ports.dst;
 569         fl6->flowi6_proto = flkeys->basic.ip_proto;
 570
 571         return true;
 572 }
 573 #else
 574 static inline bool fib6_has_custom_rules(const struct net *net)
 575 {
 576         return false;
 577 }
 578 static inline int               fib6_rules_init(void)
 579 {
 580         return 0;
 581 }
 582 static inline void              fib6_rules_cleanup(void)
 583 {
 584         return ;
 585 }
 586 static inline bool fib6_rule_default(const struct fib_rule *rule)
 587 {
 588         return true;
 589 }
 590 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb,
 591                                   struct netlink_ext_ack *extack)
 592 {
 593         return 0;
 594 }
 595 static inline unsigned int fib6_rules_seq_read(struct net *net)
 596 {
 597         return 0;
 598 }
 599 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 600                                                  struct sk_buff *skb,
 601                                                  struct flowi6 *fl6,
 602                                                  struct flow_keys *flkeys)
 603 {
 604         return false;
 605 }
 606 #endif
 607 #endif