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
  53         struct in6_addr fc_dst;
  54         struct in6_addr fc_src;
  55         struct in6_addr fc_prefsrc;
  56         struct in6_addr fc_gateway;
  57
  58         unsigned long   fc_expires;
  59         struct nlattr   *fc_mx;
  60         int             fc_mx_len;
  61         int             fc_mp_len;
  62         struct nlattr   *fc_mp;
  63
  64         struct nl_info  fc_nlinfo;
  65         struct nlattr   *fc_encap;
  66         u16             fc_encap_type;
  67 };
  68
  69 struct fib6_node {
  70         struct fib6_node __rcu  *parent;
  71         struct fib6_node __rcu  *left;
  72         struct fib6_node __rcu  *right;
  73 #ifdef CONFIG_IPV6_SUBTREES
  74         struct fib6_node __rcu  *subtree;
  75 #endif
  76         struct fib6_info __rcu  *leaf;
  77
  78         __u16                   fn_bit;         /* bit key */
  79         __u16                   fn_flags;
  80         int                     fn_sernum;
  81         struct fib6_info __rcu  *rr_ptr;
  82         struct rcu_head         rcu;
  83 };
  84
  85 struct fib6_gc_args {
  86         int                     timeout;
  87         int                     more;
  88 };
  89
  90 #ifndef CONFIG_IPV6_SUBTREES
  91 #define FIB6_SUBTREE(fn)        NULL
  92 #else
  93 #define FIB6_SUBTREE(fn)        (rcu_dereference_protected((fn)->subtree, 1))
  94 #endif
  95
  96 /*
  97  *      routing information
  98  *
  99  */
 100
 101 struct rt6key {
 102         struct in6_addr addr;
 103         int             plen;
 104 };
 105
 106 struct fib6_table;
 107
 108 struct rt6_exception_bucket {
 109         struct hlist_head       chain;
 110         int                     depth;
 111 };
 112
 113 struct rt6_exception {
 114         struct hlist_node       hlist;
 115         struct rt6_info         *rt6i;
 116         unsigned long           stamp;
 117         struct rcu_head         rcu;
 118 };
 119
 120 #define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10
 121 #define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT)
 122 #define FIB6_MAX_DEPTH 5
 123
 124 struct fib6_nh {
 125         struct fib_nh_common    nh_common;
 126
 127 #ifdef CONFIG_IPV6_ROUTER_PREF
 128         unsigned long           last_probe;
 129 #endif
 130 };
 131
 132 struct fib6_info {
 133         struct fib6_table               *fib6_table;
 134         struct fib6_info __rcu          *fib6_next;
 135         struct fib6_node __rcu          *fib6_node;
 136
 137         /* Multipath routes:
 138          * siblings is a list of fib6_info that have the the same metric/weight,
 139          * destination, but not the same gateway. nsiblings is just a cache
 140          * to speed up lookup.
 141          */
 142         struct list_head                fib6_siblings;
 143         unsigned int                    fib6_nsiblings;
 144
 145         refcount_t                      fib6_ref;
 146         unsigned long                   expires;
 147         struct dst_metrics              *fib6_metrics;
 148 #define fib6_pmtu               fib6_metrics->metrics[RTAX_MTU-1]
 149
 150         struct rt6key                   fib6_dst;
 151         u32                             fib6_flags;
 152         struct rt6key                   fib6_src;
 153         struct rt6key                   fib6_prefsrc;
 154
 155         struct rt6_info * __percpu      *rt6i_pcpu;
 156         struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
 157
 158         u32                             fib6_metric;
 159         u8                              fib6_protocol;
 160         u8                              fib6_type;
 161         u8                              exception_bucket_flushed:1,
 162                                         should_flush:1,
 163                                         dst_nocount:1,
 164                                         dst_nopolicy:1,
 165                                         dst_host:1,
 166                                         fib6_destroying:1,
 167                                         unused:2;
 168
 169         struct fib6_nh                  fib6_nh;
 170         struct rcu_head                 rcu;
 171 };
 172
 173 struct rt6_info {
 174         struct dst_entry                dst;
 175         struct fib6_info __rcu          *from;
 176
 177         struct rt6key                   rt6i_dst;
 178         struct rt6key                   rt6i_src;
 179         struct in6_addr                 rt6i_gateway;
 180         struct inet6_dev                *rt6i_idev;
 181         u32                             rt6i_flags;
 182
 183         struct list_head                rt6i_uncached;
 184         struct uncached_list            *rt6i_uncached_list;
 185
 186         /* more non-fragment space at head required */
 187         unsigned short                  rt6i_nfheader_len;
 188 };
 189
 190 struct fib6_result {
 191         struct fib6_nh          *nh;
 192         struct fib6_info        *f6i;
 193         u32                     fib6_flags;
 194         u8                      fib6_type;
 195         struct rt6_info         *rt6;
 196 };
 197
 198 #define for_each_fib6_node_rt_rcu(fn)                                   \
 199         for (rt = rcu_dereference((fn)->leaf); rt;                      \
 200              rt = rcu_dereference(rt->fib6_next))
 201
 202 #define for_each_fib6_walker_rt(w)                                      \
 203         for (rt = (w)->leaf; rt;                                        \
 204              rt = rcu_dereference_protected(rt->fib6_next, 1))
 205
 206 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 207 {
 208         return ((struct rt6_info *)dst)->rt6i_idev;
 209 }
 210
 211 static inline void fib6_clean_expires(struct fib6_info *f6i)
 212 {
 213         f6i->fib6_flags &= ~RTF_EXPIRES;
 214         f6i->expires = 0;
 215 }
 216
 217 static inline void fib6_set_expires(struct fib6_info *f6i,
 218                                     unsigned long expires)
 219 {
 220         f6i->expires = expires;
 221         f6i->fib6_flags |= RTF_EXPIRES;
 222 }
 223
 224 static inline bool fib6_check_expired(const struct fib6_info *f6i)
 225 {
 226         if (f6i->fib6_flags & RTF_EXPIRES)
 227                 return time_after(jiffies, f6i->expires);
 228         return false;
 229 }
 230
 231 /* Function to safely get fn->sernum for passed in rt
 232  * and store result in passed in cookie.
 233  * Return true if we can get cookie safely
 234  * Return false if not
 235  */
 236 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 237                                         u32 *cookie)
 238 {
 239         struct fib6_node *fn;
 240         bool status = false;
 241
 242         fn = rcu_dereference(f6i->fib6_node);
 243
 244         if (fn) {
 245                 *cookie = fn->fn_sernum;
 246                 /* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
 247                 smp_rmb();
 248                 status = true;
 249         }
 250
 251         return status;
 252 }
 253
 254 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 255 {
 256         struct fib6_info *from;
 257         u32 cookie = 0;
 258
 259         rcu_read_lock();
 260
 261         from = rcu_dereference(rt->from);
 262         if (from)
 263                 fib6_get_cookie_safe(from, &cookie);
 264
 265         rcu_read_unlock();
 266
 267         return cookie;
 268 }
 269
 270 static inline void ip6_rt_put(struct rt6_info *rt)
 271 {
 272         /* dst_release() accepts a NULL parameter.
 273          * We rely on dst being first structure in struct rt6_info
 274          */
 275         BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
 276         dst_release(&rt->dst);
 277 }
 278
 279 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags);
 280 void fib6_info_destroy_rcu(struct rcu_head *head);
 281
 282 static inline void fib6_info_hold(struct fib6_info *f6i)
 283 {
 284         refcount_inc(&f6i->fib6_ref);
 285 }
 286
 287 static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
 288 {
 289         return refcount_inc_not_zero(&f6i->fib6_ref);
 290 }
 291
 292 static inline void fib6_info_release(struct fib6_info *f6i)
 293 {
 294         if (f6i && refcount_dec_and_test(&f6i->fib6_ref))
 295                 call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
 296 }
 297
 298 enum fib6_walk_state {
 299 #ifdef CONFIG_IPV6_SUBTREES
 300         FWS_S,
 301 #endif
 302         FWS_L,
 303         FWS_R,
 304         FWS_C,
 305         FWS_U
 306 };
 307
 308 struct fib6_walker {
 309         struct list_head lh;
 310         struct fib6_node *root, *node;
 311         struct fib6_info *leaf;
 312         enum fib6_walk_state state;
 313         unsigned int skip;
 314         unsigned int count;
 315         int (*func)(struct fib6_walker *);
 316         void *args;
 317 };
 318
 319 struct rt6_statistics {
 320         __u32           fib_nodes;              /* all fib6 nodes */
 321         __u32           fib_route_nodes;        /* intermediate nodes */
 322         __u32           fib_rt_entries;         /* rt entries in fib table */
 323         __u32           fib_rt_cache;           /* cached rt entries in exception table */
 324         __u32           fib_discarded_routes;   /* total number of routes delete */
 325
 326         /* The following stats are not protected by any lock */
 327         atomic_t        fib_rt_alloc;           /* total number of routes alloced */
 328         atomic_t        fib_rt_uncache;         /* rt entries in uncached list */
 329 };
 330
 331 #define RTN_TL_ROOT     0x0001
 332 #define RTN_ROOT        0x0002          /* tree root node               */
 333 #define RTN_RTINFO      0x0004          /* node with valid routing info */
 334
 335 /*
 336  *      priority levels (or metrics)
 337  *
 338  */
 339
 340
 341 struct fib6_table {
 342         struct hlist_node       tb6_hlist;
 343         u32                     tb6_id;
 344         spinlock_t              tb6_lock;
 345         struct fib6_node        tb6_root;
 346         struct inet_peer_base   tb6_peers;
 347         unsigned int            flags;
 348         unsigned int            fib_seq;
 349 #define RT6_TABLE_HAS_DFLT_ROUTER       BIT(0)
 350 };
 351
 352 #define RT6_TABLE_UNSPEC        RT_TABLE_UNSPEC
 353 #define RT6_TABLE_MAIN          RT_TABLE_MAIN
 354 #define RT6_TABLE_DFLT          RT6_TABLE_MAIN
 355 #define RT6_TABLE_INFO          RT6_TABLE_MAIN
 356 #define RT6_TABLE_PREFIX        RT6_TABLE_MAIN
 357
 358 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 359 #define FIB6_TABLE_MIN          1
 360 #define FIB6_TABLE_MAX          RT_TABLE_MAX
 361 #define RT6_TABLE_LOCAL         RT_TABLE_LOCAL
 362 #else
 363 #define FIB6_TABLE_MIN          RT_TABLE_MAIN
 364 #define FIB6_TABLE_MAX          FIB6_TABLE_MIN
 365 #define RT6_TABLE_LOCAL         RT6_TABLE_MAIN
 366 #endif
 367
 368 typedef struct rt6_info *(*pol_lookup_t)(struct net *,
 369                                          struct fib6_table *,
 370                                          struct flowi6 *,
 371                                          const struct sk_buff *, int);
 372
 373 struct fib6_entry_notifier_info {
 374         struct fib_notifier_info info; /* must be first */
 375         struct fib6_info *rt;
 376 };
 377
 378 /*
 379  *      exported functions
 380  */
 381
 382 struct fib6_table *fib6_get_table(struct net *net, u32 id);
 383 struct fib6_table *fib6_new_table(struct net *net, u32 id);
 384 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 385                                    const struct sk_buff *skb,
 386                                    int flags, pol_lookup_t lookup);
 387
 388 /* called with rcu lock held; can return error pointer
 389  * caller needs to select path
 390  */
 391 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 392                 struct fib6_result *res, int flags);
 393
 394 /* called with rcu lock held; caller needs to select path */
 395 int fib6_table_lookup(struct net *net, struct fib6_table *table,
 396                       int oif, struct flowi6 *fl6, struct fib6_result *res,
 397                       int strict);
 398
 399 void fib6_select_path(const struct net *net, struct fib6_result *res,
 400                       struct flowi6 *fl6, int oif, bool have_oif_match,
 401                       const struct sk_buff *skb, int strict);
 402 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
 403                                    const struct in6_addr *daddr,
 404                                    const struct in6_addr *saddr);
 405
 406 struct fib6_node *fib6_locate(struct fib6_node *root,
 407                               const struct in6_addr *daddr, int dst_len,
 408                               const struct in6_addr *saddr, int src_len,
 409                               bool exact_match);
 410
 411 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
 412                     void *arg);
 413 void fib6_clean_all_skip_notify(struct net *net,
 414                                 int (*func)(struct fib6_info *, void *arg),
 415                                 void *arg);
 416
 417 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 418              struct nl_info *info, struct netlink_ext_ack *extack);
 419 int fib6_del(struct fib6_info *rt, struct nl_info *info);
 420
 421 static inline
 422 void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
 423 {
 424         const struct fib6_info *from;
 425
 426         rcu_read_lock();
 427
 428         from = rcu_dereference(rt->from);
 429         if (from) {
 430                 *addr = from->fib6_prefsrc.addr;
 431         } else {
 432                 struct in6_addr in6_zero = {};
 433
 434                 *addr = in6_zero;
 435         }
 436
 437         rcu_read_unlock();
 438 }
 439
 440 static inline struct net_device *fib6_info_nh_dev(const struct fib6_info *f6i)
 441 {
 442         return f6i->fib6_nh.fib_nh_dev;
 443 }
 444
 445 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
 446                  struct fib6_config *cfg, gfp_t gfp_flags,
 447                  struct netlink_ext_ack *extack);
 448 void fib6_nh_release(struct fib6_nh *fib6_nh);
 449
 450 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
 451                      unsigned int flags);
 452
 453 void fib6_run_gc(unsigned long expires, struct net *net, bool force);
 454
 455 void fib6_gc_cleanup(void);
 456
 457 int fib6_init(void);
 458
 459 struct ipv6_route_iter {
 460         struct seq_net_private p;
 461         struct fib6_walker w;
 462         loff_t skip;
 463         struct fib6_table *tbl;
 464         int sernum;
 465 };
 466
 467 extern const struct seq_operations ipv6_route_seq_ops;
 468
 469 int call_fib6_notifier(struct notifier_block *nb, struct net *net,
 470                        enum fib_event_type event_type,
 471                        struct fib_notifier_info *info);
 472 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
 473                         struct fib_notifier_info *info);
 474
 475 int __net_init fib6_notifier_init(struct net *net);
 476 void __net_exit fib6_notifier_exit(struct net *net);
 477
 478 unsigned int fib6_tables_seq_read(struct net *net);
 479 int fib6_tables_dump(struct net *net, struct notifier_block *nb);
 480
 481 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
 482 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
 483
 484 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 485 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
 486 {
 487         return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
 488 }
 489
 490 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 491 int fib6_rules_init(void);
 492 void fib6_rules_cleanup(void);
 493 bool fib6_rule_default(const struct fib_rule *rule);
 494 int fib6_rules_dump(struct net *net, struct notifier_block *nb);
 495 unsigned int fib6_rules_seq_read(struct net *net);
 496
 497 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 498                                                  struct sk_buff *skb,
 499                                                  struct flowi6 *fl6,
 500                                                  struct flow_keys *flkeys)
 501 {
 502         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
 503
 504         if (!net->ipv6.fib6_rules_require_fldissect)
 505                 return false;
 506
 507         skb_flow_dissect_flow_keys(skb, flkeys, flag);
 508         fl6->fl6_sport = flkeys->ports.src;
 509         fl6->fl6_dport = flkeys->ports.dst;
 510         fl6->flowi6_proto = flkeys->basic.ip_proto;
 511
 512         return true;
 513 }
 514 #else
 515 static inline int               fib6_rules_init(void)
 516 {
 517         return 0;
 518 }
 519 static inline void              fib6_rules_cleanup(void)
 520 {
 521         return ;
 522 }
 523 static inline bool fib6_rule_default(const struct fib_rule *rule)
 524 {
 525         return true;
 526 }
 527 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb)
 528 {
 529         return 0;
 530 }
 531 static inline unsigned int fib6_rules_seq_read(struct net *net)
 532 {
 533         return 0;
 534 }
 535 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 536                                                  struct sk_buff *skb,
 537                                                  struct flowi6 *fl6,
 538                                                  struct flow_keys *flkeys)
 539 {
 540         return false;
 541 }
 542 #endif
 543 #endif