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         u32                             fib6_metric;
 163         u8                              fib6_protocol;
 164         u8                              fib6_type;
 165         u8                              exception_bucket_flushed:1,
 166                                         should_flush:1,
 167                                         dst_nocount:1,
 168                                         dst_nopolicy:1,
 169                                         dst_host:1,
 170                                         unused:3;
 171
 172         struct fib6_nh                  fib6_nh;
 173         struct rcu_head                 rcu;
 174 };
 175
 176 struct rt6_info {
 177         struct dst_entry                dst;
 178         struct fib6_info __rcu          *from;
 179
 180         struct rt6key                   rt6i_dst;
 181         struct rt6key                   rt6i_src;
 182         struct in6_addr                 rt6i_gateway;
 183         struct inet6_dev                *rt6i_idev;
 184         u32                             rt6i_flags;
 185         struct rt6key                   rt6i_prefsrc;
 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 #define for_each_fib6_node_rt_rcu(fn)                                   \
 195         for (rt = rcu_dereference((fn)->leaf); rt;                      \
 196              rt = rcu_dereference(rt->fib6_next))
 197
 198 #define for_each_fib6_walker_rt(w)                                      \
 199         for (rt = (w)->leaf; rt;                                        \
 200              rt = rcu_dereference_protected(rt->fib6_next, 1))
 201
 202 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 203 {
 204         return ((struct rt6_info *)dst)->rt6i_idev;
 205 }
 206
 207 static inline void fib6_clean_expires(struct fib6_info *f6i)
 208 {
 209         f6i->fib6_flags &= ~RTF_EXPIRES;
 210         f6i->expires = 0;
 211 }
 212
 213 static inline void fib6_set_expires(struct fib6_info *f6i,
 214                                     unsigned long expires)
 215 {
 216         f6i->expires = expires;
 217         f6i->fib6_flags |= RTF_EXPIRES;
 218 }
 219
 220 static inline bool fib6_check_expired(const struct fib6_info *f6i)
 221 {
 222         if (f6i->fib6_flags & RTF_EXPIRES)
 223                 return time_after(jiffies, f6i->expires);
 224         return false;
 225 }
 226
 227 /* Function to safely get fn->sernum for passed in rt
 228  * and store result in passed in cookie.
 229  * Return true if we can get cookie safely
 230  * Return false if not
 231  */
 232 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 233                                         u32 *cookie)
 234 {
 235         struct fib6_node *fn;
 236         bool status = false;
 237
 238         fn = rcu_dereference(f6i->fib6_node);
 239
 240         if (fn) {
 241                 *cookie = fn->fn_sernum;
 242                 /* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
 243                 smp_rmb();
 244                 status = true;
 245         }
 246
 247         return status;
 248 }
 249
 250 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 251 {
 252         struct fib6_info *from;
 253         u32 cookie = 0;
 254
 255         rcu_read_lock();
 256
 257         from = rcu_dereference(rt->from);
 258         if (from && (rt->rt6i_flags & RTF_PCPU ||
 259             unlikely(!list_empty(&rt->rt6i_uncached))))
 260                 fib6_get_cookie_safe(from, &cookie);
 261
 262         rcu_read_unlock();
 263
 264         return cookie;
 265 }
 266
 267 static inline void ip6_rt_put(struct rt6_info *rt)
 268 {
 269         /* dst_release() accepts a NULL parameter.
 270          * We rely on dst being first structure in struct rt6_info
 271          */
 272         BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
 273         dst_release(&rt->dst);
 274 }
 275
 276 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags);
 277 void fib6_info_destroy_rcu(struct rcu_head *head);
 278
 279 static inline void fib6_info_hold(struct fib6_info *f6i)
 280 {
 281         atomic_inc(&f6i->fib6_ref);
 282 }
 283
 284 static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
 285 {
 286         return atomic_inc_not_zero(&f6i->fib6_ref);
 287 }
 288
 289 static inline void fib6_info_release(struct fib6_info *f6i)
 290 {
 291         if (f6i && atomic_dec_and_test(&f6i->fib6_ref))
 292                 call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
 293 }
 294
 295 enum fib6_walk_state {
 296 #ifdef CONFIG_IPV6_SUBTREES
 297         FWS_S,
 298 #endif
 299         FWS_L,
 300         FWS_R,
 301         FWS_C,
 302         FWS_U
 303 };
 304
 305 struct fib6_walker {
 306         struct list_head lh;
 307         struct fib6_node *root, *node;
 308         struct fib6_info *leaf;
 309         enum fib6_walk_state state;
 310         unsigned int skip;
 311         unsigned int count;
 312         int (*func)(struct fib6_walker *);
 313         void *args;
 314 };
 315
 316 struct rt6_statistics {
 317         __u32           fib_nodes;              /* all fib6 nodes */
 318         __u32           fib_route_nodes;        /* intermediate nodes */
 319         __u32           fib_rt_entries;         /* rt entries in fib table */
 320         __u32           fib_rt_cache;           /* cached rt entries in exception table */
 321         __u32           fib_discarded_routes;   /* total number of routes delete */
 322
 323         /* The following stats are not protected by any lock */
 324         atomic_t        fib_rt_alloc;           /* total number of routes alloced */
 325         atomic_t        fib_rt_uncache;         /* rt entries in uncached list */
 326 };
 327
 328 #define RTN_TL_ROOT     0x0001
 329 #define RTN_ROOT        0x0002          /* tree root node               */
 330 #define RTN_RTINFO      0x0004          /* node with valid routing info */
 331
 332 /*
 333  *      priority levels (or metrics)
 334  *
 335  */
 336
 337
 338 struct fib6_table {
 339         struct hlist_node       tb6_hlist;
 340         u32                     tb6_id;
 341         spinlock_t              tb6_lock;
 342         struct fib6_node        tb6_root;
 343         struct inet_peer_base   tb6_peers;
 344         unsigned int            flags;
 345         unsigned int            fib_seq;
 346 #define RT6_TABLE_HAS_DFLT_ROUTER       BIT(0)
 347 };
 348
 349 #define RT6_TABLE_UNSPEC        RT_TABLE_UNSPEC
 350 #define RT6_TABLE_MAIN          RT_TABLE_MAIN
 351 #define RT6_TABLE_DFLT          RT6_TABLE_MAIN
 352 #define RT6_TABLE_INFO          RT6_TABLE_MAIN
 353 #define RT6_TABLE_PREFIX        RT6_TABLE_MAIN
 354
 355 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 356 #define FIB6_TABLE_MIN          1
 357 #define FIB6_TABLE_MAX          RT_TABLE_MAX
 358 #define RT6_TABLE_LOCAL         RT_TABLE_LOCAL
 359 #else
 360 #define FIB6_TABLE_MIN          RT_TABLE_MAIN
 361 #define FIB6_TABLE_MAX          FIB6_TABLE_MIN
 362 #define RT6_TABLE_LOCAL         RT6_TABLE_MAIN
 363 #endif
 364
 365 typedef struct rt6_info *(*pol_lookup_t)(struct net *,
 366                                          struct fib6_table *,
 367                                          struct flowi6 *,
 368                                          const struct sk_buff *, int);
 369
 370 struct fib6_entry_notifier_info {
 371         struct fib_notifier_info info; /* must be first */
 372         struct fib6_info *rt;
 373 };
 374
 375 /*
 376  *      exported functions
 377  */
 378
 379 struct fib6_table *fib6_get_table(struct net *net, u32 id);
 380 struct fib6_table *fib6_new_table(struct net *net, u32 id);
 381 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 382                                    const struct sk_buff *skb,
 383                                    int flags, pol_lookup_t lookup);
 384
 385 /* called with rcu lock held; can return error pointer
 386  * caller needs to select path
 387  */
 388 struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 389                               int flags);
 390
 391 /* called with rcu lock held; caller needs to select path */
 392 struct fib6_info *fib6_table_lookup(struct net *net, struct fib6_table *table,
 393                                     int oif, struct flowi6 *fl6, int strict);
 394
 395 struct fib6_info *fib6_multipath_select(const struct net *net,
 396                                         struct fib6_info *match,
 397                                         struct flowi6 *fl6, int oif,
 398                                         const struct sk_buff *skb, int strict);
 399
 400 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
 401                                    const struct in6_addr *daddr,
 402                                    const struct in6_addr *saddr);
 403
 404 struct fib6_node *fib6_locate(struct fib6_node *root,
 405                               const struct in6_addr *daddr, int dst_len,
 406                               const struct in6_addr *saddr, int src_len,
 407                               bool exact_match);
 408
 409 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
 410                     void *arg);
 411
 412 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 413              struct nl_info *info, struct netlink_ext_ack *extack);
 414 int fib6_del(struct fib6_info *rt, struct nl_info *info);
 415
 416 static inline struct net_device *fib6_info_nh_dev(const struct fib6_info *f6i)
 417 {
 418         return f6i->fib6_nh.nh_dev;
 419 }
 420
 421 static inline
 422 struct lwtunnel_state *fib6_info_nh_lwt(const struct fib6_info *f6i)
 423 {
 424         return f6i->fib6_nh.nh_lwtstate;
 425 }
 426
 427 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
 428                      unsigned int flags);
 429
 430 void fib6_run_gc(unsigned long expires, struct net *net, bool force);
 431
 432 void fib6_gc_cleanup(void);
 433
 434 int fib6_init(void);
 435
 436 struct ipv6_route_iter {
 437         struct seq_net_private p;
 438         struct fib6_walker w;
 439         loff_t skip;
 440         struct fib6_table *tbl;
 441         int sernum;
 442 };
 443
 444 extern const struct seq_operations ipv6_route_seq_ops;
 445
 446 int call_fib6_notifier(struct notifier_block *nb, struct net *net,
 447                        enum fib_event_type event_type,
 448                        struct fib_notifier_info *info);
 449 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
 450                         struct fib_notifier_info *info);
 451
 452 int __net_init fib6_notifier_init(struct net *net);
 453 void __net_exit fib6_notifier_exit(struct net *net);
 454
 455 unsigned int fib6_tables_seq_read(struct net *net);
 456 int fib6_tables_dump(struct net *net, struct notifier_block *nb);
 457
 458 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
 459 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
 460
 461 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 462 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
 463 {
 464         return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
 465 }
 466
 467 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 468 int fib6_rules_init(void);
 469 void fib6_rules_cleanup(void);
 470 bool fib6_rule_default(const struct fib_rule *rule);
 471 int fib6_rules_dump(struct net *net, struct notifier_block *nb);
 472 unsigned int fib6_rules_seq_read(struct net *net);
 473
 474 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 475                                                  struct sk_buff *skb,
 476                                                  struct flowi6 *fl6,
 477                                                  struct flow_keys *flkeys)
 478 {
 479         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
 480
 481         if (!net->ipv6.fib6_rules_require_fldissect)
 482                 return false;
 483
 484         skb_flow_dissect_flow_keys(skb, flkeys, flag);
 485         fl6->fl6_sport = flkeys->ports.src;
 486         fl6->fl6_dport = flkeys->ports.dst;
 487         fl6->flowi6_proto = flkeys->basic.ip_proto;
 488
 489         return true;
 490 }
 491 #else
 492 static inline int               fib6_rules_init(void)
 493 {
 494         return 0;
 495 }
 496 static inline void              fib6_rules_cleanup(void)
 497 {
 498         return ;
 499 }
 500 static inline bool fib6_rule_default(const struct fib_rule *rule)
 501 {
 502         return true;
 503 }
 504 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb)
 505 {
 506         return 0;
 507 }
 508 static inline unsigned int fib6_rules_seq_read(struct net *net)
 509 {
 510         return 0;
 511 }
 512 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 513                                                  struct sk_buff *skb,
 514                                                  struct flowi6 *fl6,
 515                                                  struct flow_keys *flkeys)
 516 {
 517         return false;
 518 }
 519 #endif
 520 #endif