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                                         dst_host:1,
 194                                         fib6_destroying:1,
 195                                         unused:3;
 196
 197         struct rcu_head                 rcu;
 198         struct nexthop                  *nh;
 199         struct fib6_nh                  fib6_nh[0];
 200 };
 201
 202 struct rt6_info {
 203         struct dst_entry                dst;
 204         struct fib6_info __rcu          *from;
 205
 206         struct rt6key                   rt6i_dst;
 207         struct rt6key                   rt6i_src;
 208         struct in6_addr                 rt6i_gateway;
 209         struct inet6_dev                *rt6i_idev;
 210         u32                             rt6i_flags;
 211
 212         struct list_head                rt6i_uncached;
 213         struct uncached_list            *rt6i_uncached_list;
 214
 215         /* more non-fragment space at head required */
 216         unsigned short                  rt6i_nfheader_len;
 217 };
 218
 219 struct fib6_result {
 220         struct fib6_nh          *nh;
 221         struct fib6_info        *f6i;
 222         u32                     fib6_flags;
 223         u8                      fib6_type;
 224         struct rt6_info         *rt6;
 225 };
 226
 227 #define for_each_fib6_node_rt_rcu(fn)                                   \
 228         for (rt = rcu_dereference((fn)->leaf); rt;                      \
 229              rt = rcu_dereference(rt->fib6_next))
 230
 231 #define for_each_fib6_walker_rt(w)                                      \
 232         for (rt = (w)->leaf; rt;                                        \
 233              rt = rcu_dereference_protected(rt->fib6_next, 1))
 234
 235 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 236 {
 237         return ((struct rt6_info *)dst)->rt6i_idev;
 238 }
 239
 240 static inline bool fib6_requires_src(const struct fib6_info *rt)
 241 {
 242         return rt->fib6_src.plen > 0;
 243 }
 244
 245 static inline void fib6_clean_expires(struct fib6_info *f6i)
 246 {
 247         f6i->fib6_flags &= ~RTF_EXPIRES;
 248         f6i->expires = 0;
 249 }
 250
 251 static inline void fib6_set_expires(struct fib6_info *f6i,
 252                                     unsigned long expires)
 253 {
 254         f6i->expires = expires;
 255         f6i->fib6_flags |= RTF_EXPIRES;
 256 }
 257
 258 static inline bool fib6_check_expired(const struct fib6_info *f6i)
 259 {
 260         if (f6i->fib6_flags & RTF_EXPIRES)
 261                 return time_after(jiffies, f6i->expires);
 262         return false;
 263 }
 264
 265 /* Function to safely get fn->sernum for passed in rt
 266  * and store result in passed in cookie.
 267  * Return true if we can get cookie safely
 268  * Return false if not
 269  */
 270 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 271                                         u32 *cookie)
 272 {
 273         struct fib6_node *fn;
 274         bool status = false;
 275
 276         fn = rcu_dereference(f6i->fib6_node);
 277
 278         if (fn) {
 279                 *cookie = fn->fn_sernum;
 280                 /* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
 281                 smp_rmb();
 282                 status = true;
 283         }
 284
 285         return status;
 286 }
 287
 288 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 289 {
 290         struct fib6_info *from;
 291         u32 cookie = 0;
 292
 293         rcu_read_lock();
 294
 295         from = rcu_dereference(rt->from);
 296         if (from)
 297                 fib6_get_cookie_safe(from, &cookie);
 298
 299         rcu_read_unlock();
 300
 301         return cookie;
 302 }
 303
 304 static inline void ip6_rt_put(struct rt6_info *rt)
 305 {
 306         /* dst_release() accepts a NULL parameter.
 307          * We rely on dst being first structure in struct rt6_info
 308          */
 309         BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
 310         dst_release(&rt->dst);
 311 }
 312
 313 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh);
 314 void fib6_info_destroy_rcu(struct rcu_head *head);
 315
 316 static inline void fib6_info_hold(struct fib6_info *f6i)
 317 {
 318         refcount_inc(&f6i->fib6_ref);
 319 }
 320
 321 static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
 322 {
 323         return refcount_inc_not_zero(&f6i->fib6_ref);
 324 }
 325
 326 static inline void fib6_info_release(struct fib6_info *f6i)
 327 {
 328         if (f6i && refcount_dec_and_test(&f6i->fib6_ref))
 329                 call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
 330 }
 331
 332 enum fib6_walk_state {
 333 #ifdef CONFIG_IPV6_SUBTREES
 334         FWS_S,
 335 #endif
 336         FWS_L,
 337         FWS_R,
 338         FWS_C,
 339         FWS_U
 340 };
 341
 342 struct fib6_walker {
 343         struct list_head lh;
 344         struct fib6_node *root, *node;
 345         struct fib6_info *leaf;
 346         enum fib6_walk_state state;
 347         unsigned int skip;
 348         unsigned int count;
 349         unsigned int skip_in_node;
 350         int (*func)(struct fib6_walker *);
 351         void *args;
 352 };
 353
 354 struct rt6_statistics {
 355         __u32           fib_nodes;              /* all fib6 nodes */
 356         __u32           fib_route_nodes;        /* intermediate nodes */
 357         __u32           fib_rt_entries;         /* rt entries in fib table */
 358         __u32           fib_rt_cache;           /* cached rt entries in exception table */
 359         __u32           fib_discarded_routes;   /* total number of routes delete */
 360
 361         /* The following stats are not protected by any lock */
 362         atomic_t        fib_rt_alloc;           /* total number of routes alloced */
 363         atomic_t        fib_rt_uncache;         /* rt entries in uncached list */
 364 };
 365
 366 #define RTN_TL_ROOT     0x0001
 367 #define RTN_ROOT        0x0002          /* tree root node               */
 368 #define RTN_RTINFO      0x0004          /* node with valid routing info */
 369
 370 /*
 371  *      priority levels (or metrics)
 372  *
 373  */
 374
 375
 376 struct fib6_table {
 377         struct hlist_node       tb6_hlist;
 378         u32                     tb6_id;
 379         spinlock_t              tb6_lock;
 380         struct fib6_node        tb6_root;
 381         struct inet_peer_base   tb6_peers;
 382         unsigned int            flags;
 383         unsigned int            fib_seq;
 384 #define RT6_TABLE_HAS_DFLT_ROUTER       BIT(0)
 385 };
 386
 387 #define RT6_TABLE_UNSPEC        RT_TABLE_UNSPEC
 388 #define RT6_TABLE_MAIN          RT_TABLE_MAIN
 389 #define RT6_TABLE_DFLT          RT6_TABLE_MAIN
 390 #define RT6_TABLE_INFO          RT6_TABLE_MAIN
 391 #define RT6_TABLE_PREFIX        RT6_TABLE_MAIN
 392
 393 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 394 #define FIB6_TABLE_MIN          1
 395 #define FIB6_TABLE_MAX          RT_TABLE_MAX
 396 #define RT6_TABLE_LOCAL         RT_TABLE_LOCAL
 397 #else
 398 #define FIB6_TABLE_MIN          RT_TABLE_MAIN
 399 #define FIB6_TABLE_MAX          FIB6_TABLE_MIN
 400 #define RT6_TABLE_LOCAL         RT6_TABLE_MAIN
 401 #endif
 402
 403 typedef struct rt6_info *(*pol_lookup_t)(struct net *,
 404                                          struct fib6_table *,
 405                                          struct flowi6 *,
 406                                          const struct sk_buff *, int);
 407
 408 struct fib6_entry_notifier_info {
 409         struct fib_notifier_info info; /* must be first */
 410         struct fib6_info *rt;
 411         unsigned int nsiblings;
 412 };
 413
 414 /*
 415  *      exported functions
 416  */
 417
 418 struct fib6_table *fib6_get_table(struct net *net, u32 id);
 419 struct fib6_table *fib6_new_table(struct net *net, u32 id);
 420 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 421                                    const struct sk_buff *skb,
 422                                    int flags, pol_lookup_t lookup);
 423
 424 /* called with rcu lock held; can return error pointer
 425  * caller needs to select path
 426  */
 427 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 428                 struct fib6_result *res, int flags);
 429
 430 /* called with rcu lock held; caller needs to select path */
 431 int fib6_table_lookup(struct net *net, struct fib6_table *table,
 432                       int oif, struct flowi6 *fl6, struct fib6_result *res,
 433                       int strict);
 434
 435 void fib6_select_path(const struct net *net, struct fib6_result *res,
 436                       struct flowi6 *fl6, int oif, bool have_oif_match,
 437                       const struct sk_buff *skb, int strict);
 438 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
 439                                    const struct in6_addr *daddr,
 440                                    const struct in6_addr *saddr);
 441
 442 struct fib6_node *fib6_locate(struct fib6_node *root,
 443                               const struct in6_addr *daddr, int dst_len,
 444                               const struct in6_addr *saddr, int src_len,
 445                               bool exact_match);
 446
 447 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
 448                     void *arg);
 449 void fib6_clean_all_skip_notify(struct net *net,
 450                                 int (*func)(struct fib6_info *, void *arg),
 451                                 void *arg);
 452
 453 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 454              struct nl_info *info, struct netlink_ext_ack *extack);
 455 int fib6_del(struct fib6_info *rt, struct nl_info *info);
 456
 457 static inline
 458 void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
 459 {
 460         const struct fib6_info *from;
 461
 462         rcu_read_lock();
 463
 464         from = rcu_dereference(rt->from);
 465         if (from) {
 466                 *addr = from->fib6_prefsrc.addr;
 467         } else {
 468                 struct in6_addr in6_zero = {};
 469
 470                 *addr = in6_zero;
 471         }
 472
 473         rcu_read_unlock();
 474 }
 475
 476 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
 477                  struct fib6_config *cfg, gfp_t gfp_flags,
 478                  struct netlink_ext_ack *extack);
 479 void fib6_nh_release(struct fib6_nh *fib6_nh);
 480
 481 int call_fib6_entry_notifiers(struct net *net,
 482                               enum fib_event_type event_type,
 483                               struct fib6_info *rt,
 484                               struct netlink_ext_ack *extack);
 485 int call_fib6_multipath_entry_notifiers(struct net *net,
 486                                         enum fib_event_type event_type,
 487                                         struct fib6_info *rt,
 488                                         unsigned int nsiblings,
 489                                         struct netlink_ext_ack *extack);
 490 void fib6_rt_update(struct net *net, struct fib6_info *rt,
 491                     struct nl_info *info);
 492 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
 493                      unsigned int flags);
 494
 495 void fib6_run_gc(unsigned long expires, struct net *net, bool force);
 496
 497 void fib6_gc_cleanup(void);
 498
 499 int fib6_init(void);
 500
 501 struct ipv6_route_iter {
 502         struct seq_net_private p;
 503         struct fib6_walker w;
 504         loff_t skip;
 505         struct fib6_table *tbl;
 506         int sernum;
 507 };
 508
 509 extern const struct seq_operations ipv6_route_seq_ops;
 510
 511 int call_fib6_notifier(struct notifier_block *nb,
 512                        enum fib_event_type event_type,
 513                        struct fib_notifier_info *info);
 514 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
 515                         struct fib_notifier_info *info);
 516
 517 int __net_init fib6_notifier_init(struct net *net);
 518 void __net_exit fib6_notifier_exit(struct net *net);
 519
 520 unsigned int fib6_tables_seq_read(struct net *net);
 521 int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 522                      struct netlink_ext_ack *extack);
 523
 524 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
 525 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
 526 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i);
 527
 528 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 529 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
 530 {
 531         return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
 532 }
 533
 534 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 535 static inline bool fib6_has_custom_rules(const struct net *net)
 536 {
 537         return net->ipv6.fib6_has_custom_rules;
 538 }
 539
 540 int fib6_rules_init(void);
 541 void fib6_rules_cleanup(void);
 542 bool fib6_rule_default(const struct fib_rule *rule);
 543 int fib6_rules_dump(struct net *net, struct notifier_block *nb,
 544                     struct netlink_ext_ack *extack);
 545 unsigned int fib6_rules_seq_read(struct net *net);
 546
 547 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 548                                                  struct sk_buff *skb,
 549                                                  struct flowi6 *fl6,
 550                                                  struct flow_keys *flkeys)
 551 {
 552         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
 553
 554         if (!net->ipv6.fib6_rules_require_fldissect)
 555                 return false;
 556
 557         skb_flow_dissect_flow_keys(skb, flkeys, flag);
 558         fl6->fl6_sport = flkeys->ports.src;
 559         fl6->fl6_dport = flkeys->ports.dst;
 560         fl6->flowi6_proto = flkeys->basic.ip_proto;
 561
 562         return true;
 563 }
 564 #else
 565 static inline bool fib6_has_custom_rules(const struct net *net)
 566 {
 567         return false;
 568 }
 569 static inline int               fib6_rules_init(void)
 570 {
 571         return 0;
 572 }
 573 static inline void              fib6_rules_cleanup(void)
 574 {
 575         return ;
 576 }
 577 static inline bool fib6_rule_default(const struct fib_rule *rule)
 578 {
 579         return true;
 580 }
 581 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb,
 582                                   struct netlink_ext_ack *extack)
 583 {
 584         return 0;
 585 }
 586 static inline unsigned int fib6_rules_seq_read(struct net *net)
 587 {
 588         return 0;
 589 }
 590 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 591                                                  struct sk_buff *skb,
 592                                                  struct flowi6 *fl6,
 593                                                  struct flow_keys *flkeys)
 594 {
 595         return false;
 596 }
 597 #endif
 598 #endif