include/net/ip6_fib.h

   1 /*
   2  *      Linux INET6 implementation
   3  *
   4  *      Authors:
   5  *      Pedro Roque             <roque@di.fc.ul.pt>
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  */
  12
  13 #ifndef _IP6_FIB_H
  14 #define _IP6_FIB_H
  15
  16 #include <linux/ipv6_route.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/notifier.h>
  20 #include <net/dst.h>
  21 #include <net/flow.h>
  22 #include <net/netlink.h>
  23 #include <net/inetpeer.h>
  24 #include <net/fib_notifier.h>
  25
  26 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
  27 #define FIB6_TABLE_HASHSZ 256
  28 #else
  29 #define FIB6_TABLE_HASHSZ 1
  30 #endif
  31
  32 #define RT6_DEBUG 2
  33
  34 #if RT6_DEBUG >= 3
  35 #define RT6_TRACE(x...) pr_debug(x)
  36 #else
  37 #define RT6_TRACE(x...) do { ; } while (0)
  38 #endif
  39
  40 struct rt6_info;
  41 struct fib6_info;
  42
  43 struct fib6_config {
  44         u32             fc_table;
  45         u32             fc_metric;
  46         int             fc_dst_len;
  47         int             fc_src_len;
  48         int             fc_ifindex;
  49         u32             fc_flags;
  50         u32             fc_protocol;
  51         u16             fc_type;        /* only 8 bits are used */
  52         u16             fc_delete_all_nh : 1,
  53                         __unused : 15;
  54
  55         struct in6_addr fc_dst;
  56         struct in6_addr fc_src;
  57         struct in6_addr fc_prefsrc;
  58         struct in6_addr fc_gateway;
  59
  60         unsigned long   fc_expires;
  61         struct nlattr   *fc_mx;
  62         int             fc_mx_len;
  63         int             fc_mp_len;
  64         struct nlattr   *fc_mp;
  65
  66         struct nl_info  fc_nlinfo;
  67         struct nlattr   *fc_encap;
  68         u16             fc_encap_type;
  69 };
  70
  71 struct fib6_node {
  72         struct fib6_node __rcu  *parent;
  73         struct fib6_node __rcu  *left;
  74         struct fib6_node __rcu  *right;
  75 #ifdef CONFIG_IPV6_SUBTREES
  76         struct fib6_node __rcu  *subtree;
  77 #endif
  78         struct fib6_info __rcu  *leaf;
  79
  80         __u16                   fn_bit;         /* bit key */
  81         __u16                   fn_flags;
  82         int                     fn_sernum;
  83         struct fib6_info __rcu  *rr_ptr;
  84         struct rcu_head         rcu;
  85 };
  86
  87 struct fib6_gc_args {
  88         int                     timeout;
  89         int                     more;
  90 };
  91
  92 #ifndef CONFIG_IPV6_SUBTREES
  93 #define FIB6_SUBTREE(fn)        NULL
  94 #else
  95 #define FIB6_SUBTREE(fn)        (rcu_dereference_protected((fn)->subtree, 1))
  96 #endif
  97
  98 /*
  99  *      routing information
 100  *
 101  */
 102
 103 struct rt6key {
 104         struct in6_addr addr;
 105         int             plen;
 106 };
 107
 108 struct fib6_table;
 109
 110 struct rt6_exception_bucket {
 111         struct hlist_head       chain;
 112         int                     depth;
 113 };
 114
 115 struct rt6_exception {
 116         struct hlist_node       hlist;
 117         struct rt6_info         *rt6i;
 118         unsigned long           stamp;
 119         struct rcu_head         rcu;
 120 };
 121
 122 #define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10
 123 #define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT)
 124 #define FIB6_MAX_DEPTH 5
 125
 126 struct fib6_nh {
 127         struct in6_addr         nh_gw;
 128         struct net_device       *nh_dev;
 129         struct lwtunnel_state   *nh_lwtstate;
 130
 131         unsigned int            nh_flags;
 132         atomic_t                nh_upper_bound;
 133         int                     nh_weight;
 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         struct list_head                fib6_siblings;
 147         unsigned int                    fib6_nsiblings;
 148
 149         atomic_t                        fib6_ref;
 150         unsigned long                   expires;
 151         struct dst_metrics              *fib6_metrics;
 152 #define fib6_pmtu               fib6_metrics->metrics[RTAX_MTU-1]
 153
 154         struct rt6key                   fib6_dst;
 155         u32                             fib6_flags;
 156         struct rt6key                   fib6_src;
 157         struct rt6key                   fib6_prefsrc;
 158
 159         struct rt6_info * __percpu      *rt6i_pcpu;
 160         struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
 161
 162 #ifdef CONFIG_IPV6_ROUTER_PREF
 163         unsigned long                   last_probe;
 164 #endif
 165
 166         u32                             fib6_metric;
 167         u8                              fib6_protocol;
 168         u8                              fib6_type;
 169         u8                              exception_bucket_flushed:1,
 170                                         should_flush:1,
 171                                         dst_nocount:1,
 172                                         dst_nopolicy:1,
 173                                         dst_host:1,
 174                                         unused:3;
 175
 176         struct fib6_nh                  fib6_nh;
 177         struct rcu_head                 rcu;
 178 };
 179
 180 struct rt6_info {
 181         struct dst_entry                dst;
 182         struct fib6_info __rcu          *from;
 183
 184         struct rt6key                   rt6i_dst;
 185         struct rt6key                   rt6i_src;
 186         struct in6_addr                 rt6i_gateway;
 187         struct inet6_dev                *rt6i_idev;
 188         u32                             rt6i_flags;
 189
 190         struct list_head                rt6i_uncached;
 191         struct uncached_list            *rt6i_uncached_list;
 192
 193         /* more non-fragment space at head required */
 194         unsigned short                  rt6i_nfheader_len;
 195 };
 196
 197 #define for_each_fib6_node_rt_rcu(fn)                                   \
 198         for (rt = rcu_dereference((fn)->leaf); rt;                      \
 199              rt = rcu_dereference(rt->fib6_next))
 200
 201 #define for_each_fib6_walker_rt(w)                                      \
 202         for (rt = (w)->leaf; rt;                                        \
 203              rt = rcu_dereference_protected(rt->fib6_next, 1))
 204
 205 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 206 {
 207         return ((struct rt6_info *)dst)->rt6i_idev;
 208 }
 209
 210 static inline void fib6_clean_expires(struct fib6_info *f6i)
 211 {
 212         f6i->fib6_flags &= ~RTF_EXPIRES;
 213         f6i->expires = 0;
 214 }
 215
 216 static inline void fib6_set_expires(struct fib6_info *f6i,
 217                                     unsigned long expires)
 218 {
 219         f6i->expires = expires;
 220         f6i->fib6_flags |= RTF_EXPIRES;
 221 }
 222
 223 static inline bool fib6_check_expired(const struct fib6_info *f6i)
 224 {
 225         if (f6i->fib6_flags & RTF_EXPIRES)
 226                 return time_after(jiffies, f6i->expires);
 227         return false;
 228 }
 229
 230 /* Function to safely get fn->sernum for passed in rt
 231  * and store result in passed in cookie.
 232  * Return true if we can get cookie safely
 233  * Return false if not
 234  */
 235 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 236                                         u32 *cookie)
 237 {
 238         struct fib6_node *fn;
 239         bool status = false;
 240
 241         fn = rcu_dereference(f6i->fib6_node);
 242
 243         if (fn) {
 244                 *cookie = fn->fn_sernum;
 245                 /* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
 246                 smp_rmb();
 247                 status = true;
 248         }
 249
 250         return status;
 251 }
 252
 253 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 254 {
 255         struct fib6_info *from;
 256         u32 cookie = 0;
 257
 258         rcu_read_lock();
 259
 260         from = rcu_dereference(rt->from);
 261         if (from && (rt->rt6i_flags & RTF_PCPU ||
 262             unlikely(!list_empty(&rt->rt6i_uncached))))
 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         atomic_inc(&f6i->fib6_ref);
 285 }
 286
 287 static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
 288 {
 289         return atomic_inc_not_zero(&f6i->fib6_ref);
 290 }
 291
 292 static inline void fib6_info_release(struct fib6_info *f6i)
 293 {
 294         if (f6i && atomic_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 struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 392                               int flags);
 393
 394 /* called with rcu lock held; caller needs to select path */
 395 struct fib6_info *fib6_table_lookup(struct net *net, struct fib6_table *table,
 396                                     int oif, struct flowi6 *fl6, int strict);
 397
 398 struct fib6_info *fib6_multipath_select(const struct net *net,
 399                                         struct fib6_info *match,
 400                                         struct flowi6 *fl6, int oif,
 401                                         const struct sk_buff *skb, int strict);
 402
 403 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
 404                                    const struct in6_addr *daddr,
 405                                    const struct in6_addr *saddr);
 406
 407 struct fib6_node *fib6_locate(struct fib6_node *root,
 408                               const struct in6_addr *daddr, int dst_len,
 409                               const struct in6_addr *saddr, int src_len,
 410                               bool exact_match);
 411
 412 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
 413                     void *arg);
 414 void fib6_clean_all_skip_notify(struct net *net,
 415                                 int (*func)(struct fib6_info *, void *arg),
 416                                 void *arg);
 417
 418 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 419              struct nl_info *info, struct netlink_ext_ack *extack);
 420 int fib6_del(struct fib6_info *rt, struct nl_info *info);
 421
 422 static inline
 423 void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
 424 {
 425         const struct fib6_info *from;
 426
 427         rcu_read_lock();
 428
 429         from = rcu_dereference(rt->from);
 430         if (from) {
 431                 *addr = from->fib6_prefsrc.addr;
 432         } else {
 433                 struct in6_addr in6_zero = {};
 434
 435                 *addr = in6_zero;
 436         }
 437
 438         rcu_read_unlock();
 439 }
 440
 441 static inline struct net_device *fib6_info_nh_dev(const struct fib6_info *f6i)
 442 {
 443         return f6i->fib6_nh.nh_dev;
 444 }
 445
 446 static inline
 447 struct lwtunnel_state *fib6_info_nh_lwt(const struct fib6_info *f6i)
 448 {
 449         return f6i->fib6_nh.nh_lwtstate;
 450 }
 451
 452 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
 453                      unsigned int flags);
 454
 455 void fib6_run_gc(unsigned long expires, struct net *net, bool force);
 456
 457 void fib6_gc_cleanup(void);
 458
 459 int fib6_init(void);
 460
 461 struct ipv6_route_iter {
 462         struct seq_net_private p;
 463         struct fib6_walker w;
 464         loff_t skip;
 465         struct fib6_table *tbl;
 466         int sernum;
 467 };
 468
 469 extern const struct seq_operations ipv6_route_seq_ops;
 470
 471 int call_fib6_notifier(struct notifier_block *nb, struct net *net,
 472                        enum fib_event_type event_type,
 473                        struct fib_notifier_info *info);
 474 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
 475                         struct fib_notifier_info *info);
 476
 477 int __net_init fib6_notifier_init(struct net *net);
 478 void __net_exit fib6_notifier_exit(struct net *net);
 479
 480 unsigned int fib6_tables_seq_read(struct net *net);
 481 int fib6_tables_dump(struct net *net, struct notifier_block *nb);
 482
 483 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
 484 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
 485
 486 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 487 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
 488 {
 489         return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
 490 }
 491
 492 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 493 int fib6_rules_init(void);
 494 void fib6_rules_cleanup(void);
 495 bool fib6_rule_default(const struct fib_rule *rule);
 496 int fib6_rules_dump(struct net *net, struct notifier_block *nb);
 497 unsigned int fib6_rules_seq_read(struct net *net);
 498
 499 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 500                                                  struct sk_buff *skb,
 501                                                  struct flowi6 *fl6,
 502                                                  struct flow_keys *flkeys)
 503 {
 504         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
 505
 506         if (!net->ipv6.fib6_rules_require_fldissect)
 507                 return false;
 508
 509         skb_flow_dissect_flow_keys(skb, flkeys, flag);
 510         fl6->fl6_sport = flkeys->ports.src;
 511         fl6->fl6_dport = flkeys->ports.dst;
 512         fl6->flowi6_proto = flkeys->basic.ip_proto;
 513
 514         return true;
 515 }
 516 #else
 517 static inline int               fib6_rules_init(void)
 518 {
 519         return 0;
 520 }
 521 static inline void              fib6_rules_cleanup(void)
 522 {
 523         return ;
 524 }
 525 static inline bool fib6_rule_default(const struct fib_rule *rule)
 526 {
 527         return true;
 528 }
 529 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb)
 530 {
 531         return 0;
 532 }
 533 static inline unsigned int fib6_rules_seq_read(struct net *net)
 534 {
 535         return 0;
 536 }
 537 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 538                                                  struct sk_buff *skb,
 539                                                  struct flowi6 *fl6,
 540                                                  struct flow_keys *flkeys)
 541 {
 542         return false;
 543 }
 544 #endif
 545 #endif