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