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
  42 struct fib6_config {
  43         u32             fc_table;
  44         u32             fc_metric;
  45         int             fc_dst_len;
  46         int             fc_src_len;
  47         int             fc_ifindex;
  48         u32             fc_flags;
  49         u32             fc_protocol;
  50         u16             fc_type;        /* only 8 bits are used */
  51         u16             fc_delete_all_nh : 1,
  52                         __unused : 15;
  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 rt6_info __rcu   *leaf;
  78
  79         __u16                   fn_bit;         /* bit key */
  80         __u16                   fn_flags;
  81         int                     fn_sernum;
  82         struct rt6_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 struct mx6_config {
  98         const u32 *mx;
  99         DECLARE_BITMAP(mx_valid, RTAX_MAX);
 100 };
 101
 102 /*
 103  *      routing information
 104  *
 105  */
 106
 107 struct rt6key {
 108         struct in6_addr addr;
 109         int             plen;
 110 };
 111
 112 struct fib6_table;
 113
 114 struct rt6_exception_bucket {
 115         struct hlist_head       chain;
 116         int                     depth;
 117 };
 118
 119 struct rt6_exception {
 120         struct hlist_node       hlist;
 121         struct rt6_info         *rt6i;
 122         unsigned long           stamp;
 123         struct rcu_head         rcu;
 124 };
 125
 126 #define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10
 127 #define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT)
 128 #define FIB6_MAX_DEPTH 5
 129
 130 struct rt6_info {
 131         struct dst_entry                dst;
 132
 133         /*
 134          * Tail elements of dst_entry (__refcnt etc.)
 135          * and these elements (rarely used in hot path) are in
 136          * the same cache line.
 137          */
 138         struct fib6_table               *rt6i_table;
 139         struct fib6_node __rcu          *rt6i_node;
 140
 141         struct in6_addr                 rt6i_gateway;
 142
 143         /* Multipath routes:
 144          * siblings is a list of rt6_info that have the the same metric/weight,
 145          * destination, but not the same gateway. nsiblings is just a cache
 146          * to speed up lookup.
 147          */
 148         struct list_head                rt6i_siblings;
 149         unsigned int                    rt6i_nsiblings;
 150
 151         atomic_t                        rt6i_ref;
 152
 153         unsigned int                    rt6i_nh_flags;
 154
 155         /* These are in a separate cache line. */
 156         struct rt6key                   rt6i_dst ____cacheline_aligned_in_smp;
 157         u32                             rt6i_flags;
 158         struct rt6key                   rt6i_src;
 159         struct rt6key                   rt6i_prefsrc;
 160
 161         struct list_head                rt6i_uncached;
 162         struct uncached_list            *rt6i_uncached_list;
 163
 164         struct inet6_dev                *rt6i_idev;
 165         struct rt6_info * __percpu      *rt6i_pcpu;
 166         struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
 167
 168         u32                             rt6i_metric;
 169         u32                             rt6i_pmtu;
 170         /* more non-fragment space at head required */
 171         unsigned short                  rt6i_nfheader_len;
 172         u8                              rt6i_protocol;
 173         u8                              exception_bucket_flushed:1,
 174                                         unused:7;
 175 };
 176
 177 #define for_each_fib6_node_rt_rcu(fn)                                   \
 178         for (rt = rcu_dereference((fn)->leaf); rt;                      \
 179              rt = rcu_dereference(rt->dst.rt6_next))
 180
 181 #define for_each_fib6_walker_rt(w)                                      \
 182         for (rt = (w)->leaf; rt;                                        \
 183              rt = rcu_dereference_protected(rt->dst.rt6_next, 1))
 184
 185 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 186 {
 187         return ((struct rt6_info *)dst)->rt6i_idev;
 188 }
 189
 190 static inline void rt6_clean_expires(struct rt6_info *rt)
 191 {
 192         rt->rt6i_flags &= ~RTF_EXPIRES;
 193         rt->dst.expires = 0;
 194 }
 195
 196 static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)
 197 {
 198         rt->dst.expires = expires;
 199         rt->rt6i_flags |= RTF_EXPIRES;
 200 }
 201
 202 static inline void rt6_update_expires(struct rt6_info *rt0, int timeout)
 203 {
 204         struct rt6_info *rt;
 205
 206         for (rt = rt0; rt && !(rt->rt6i_flags & RTF_EXPIRES);
 207              rt = (struct rt6_info *)rt->dst.from);
 208         if (rt && rt != rt0)
 209                 rt0->dst.expires = rt->dst.expires;
 210
 211         dst_set_expires(&rt0->dst, timeout);
 212         rt0->rt6i_flags |= RTF_EXPIRES;
 213 }
 214
 215 /* Function to safely get fn->sernum for passed in rt
 216  * and store result in passed in cookie.
 217  * Return true if we can get cookie safely
 218  * Return false if not
 219  */
 220 static inline bool rt6_get_cookie_safe(const struct rt6_info *rt,
 221                                        u32 *cookie)
 222 {
 223         struct fib6_node *fn;
 224         bool status = false;
 225
 226         rcu_read_lock();
 227         fn = rcu_dereference(rt->rt6i_node);
 228
 229         if (fn) {
 230                 *cookie = fn->fn_sernum;
 231                 /* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
 232                 smp_rmb();
 233                 status = true;
 234         }
 235
 236         rcu_read_unlock();
 237         return status;
 238 }
 239
 240 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 241 {
 242         u32 cookie = 0;
 243
 244         if (rt->dst.from)
 245                 rt = (struct rt6_info *)(rt->dst.from);
 246
 247         rt6_get_cookie_safe(rt, &cookie);
 248
 249         return cookie;
 250 }
 251
 252 static inline void ip6_rt_put(struct rt6_info *rt)
 253 {
 254         /* dst_release() accepts a NULL parameter.
 255          * We rely on dst being first structure in struct rt6_info
 256          */
 257         BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
 258         dst_release(&rt->dst);
 259 }
 260
 261 void rt6_free_pcpu(struct rt6_info *non_pcpu_rt);
 262
 263 static inline void rt6_hold(struct rt6_info *rt)
 264 {
 265         atomic_inc(&rt->rt6i_ref);
 266 }
 267
 268 static inline void rt6_release(struct rt6_info *rt)
 269 {
 270         if (atomic_dec_and_test(&rt->rt6i_ref)) {
 271                 rt6_free_pcpu(rt);
 272                 dst_dev_put(&rt->dst);
 273                 dst_release(&rt->dst);
 274         }
 275 }
 276
 277 enum fib6_walk_state {
 278 #ifdef CONFIG_IPV6_SUBTREES
 279         FWS_S,
 280 #endif
 281         FWS_L,
 282         FWS_R,
 283         FWS_C,
 284         FWS_U
 285 };
 286
 287 struct fib6_walker {
 288         struct list_head lh;
 289         struct fib6_node *root, *node;
 290         struct rt6_info *leaf;
 291         enum fib6_walk_state state;
 292         unsigned int skip;
 293         unsigned int count;
 294         int (*func)(struct fib6_walker *);
 295         void *args;
 296 };
 297
 298 struct rt6_statistics {
 299         __u32           fib_nodes;              /* all fib6 nodes */
 300         __u32           fib_route_nodes;        /* intermediate nodes */
 301         __u32           fib_rt_entries;         /* rt entries in fib table */
 302         __u32           fib_rt_cache;           /* cached rt entries in exception table */
 303         __u32           fib_discarded_routes;   /* total number of routes delete */
 304
 305         /* The following stats are not protected by any lock */
 306         atomic_t        fib_rt_alloc;           /* total number of routes alloced */
 307         atomic_t        fib_rt_uncache;         /* rt entries in uncached list */
 308 };
 309
 310 #define RTN_TL_ROOT     0x0001
 311 #define RTN_ROOT        0x0002          /* tree root node               */
 312 #define RTN_RTINFO      0x0004          /* node with valid routing info */
 313
 314 /*
 315  *      priority levels (or metrics)
 316  *
 317  */
 318
 319
 320 struct fib6_table {
 321         struct hlist_node       tb6_hlist;
 322         u32                     tb6_id;
 323         spinlock_t              tb6_lock;
 324         struct fib6_node        tb6_root;
 325         struct inet_peer_base   tb6_peers;
 326         unsigned int            flags;
 327         unsigned int            fib_seq;
 328 #define RT6_TABLE_HAS_DFLT_ROUTER       BIT(0)
 329 };
 330
 331 #define RT6_TABLE_UNSPEC        RT_TABLE_UNSPEC
 332 #define RT6_TABLE_MAIN          RT_TABLE_MAIN
 333 #define RT6_TABLE_DFLT          RT6_TABLE_MAIN
 334 #define RT6_TABLE_INFO          RT6_TABLE_MAIN
 335 #define RT6_TABLE_PREFIX        RT6_TABLE_MAIN
 336
 337 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 338 #define FIB6_TABLE_MIN          1
 339 #define FIB6_TABLE_MAX          RT_TABLE_MAX
 340 #define RT6_TABLE_LOCAL         RT_TABLE_LOCAL
 341 #else
 342 #define FIB6_TABLE_MIN          RT_TABLE_MAIN
 343 #define FIB6_TABLE_MAX          FIB6_TABLE_MIN
 344 #define RT6_TABLE_LOCAL         RT6_TABLE_MAIN
 345 #endif
 346
 347 typedef struct rt6_info *(*pol_lookup_t)(struct net *,
 348                                          struct fib6_table *,
 349                                          struct flowi6 *, int);
 350
 351 struct fib6_entry_notifier_info {
 352         struct fib_notifier_info info; /* must be first */
 353         struct rt6_info *rt;
 354 };
 355
 356 /*
 357  *      exported functions
 358  */
 359
 360 struct fib6_table *fib6_get_table(struct net *net, u32 id);
 361 struct fib6_table *fib6_new_table(struct net *net, u32 id);
 362 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 363                                    int flags, pol_lookup_t lookup);
 364
 365 struct fib6_node *fib6_lookup(struct fib6_node *root,
 366                               const struct in6_addr *daddr,
 367                               const struct in6_addr *saddr);
 368
 369 struct fib6_node *fib6_locate(struct fib6_node *root,
 370                               const struct in6_addr *daddr, int dst_len,
 371                               const struct in6_addr *saddr, int src_len,
 372                               bool exact_match);
 373
 374 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
 375                     void *arg);
 376
 377 int fib6_add(struct fib6_node *root, struct rt6_info *rt,
 378              struct nl_info *info, struct mx6_config *mxc,
 379              struct netlink_ext_ack *extack);
 380 int fib6_del(struct rt6_info *rt, struct nl_info *info);
 381
 382 void inet6_rt_notify(int event, struct rt6_info *rt, struct nl_info *info,
 383                      unsigned int flags);
 384
 385 void fib6_run_gc(unsigned long expires, struct net *net, bool force);
 386
 387 void fib6_gc_cleanup(void);
 388
 389 int fib6_init(void);
 390
 391 int ipv6_route_open(struct inode *inode, struct file *file);
 392
 393 int call_fib6_notifier(struct notifier_block *nb, struct net *net,
 394                        enum fib_event_type event_type,
 395                        struct fib_notifier_info *info);
 396 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
 397                         struct fib_notifier_info *info);
 398
 399 int __net_init fib6_notifier_init(struct net *net);
 400 void __net_exit fib6_notifier_exit(struct net *net);
 401
 402 unsigned int fib6_tables_seq_read(struct net *net);
 403 int fib6_tables_dump(struct net *net, struct notifier_block *nb);
 404
 405 void fib6_update_sernum(struct rt6_info *rt);
 406
 407 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 408 int fib6_rules_init(void);
 409 void fib6_rules_cleanup(void);
 410 bool fib6_rule_default(const struct fib_rule *rule);
 411 int fib6_rules_dump(struct net *net, struct notifier_block *nb);
 412 unsigned int fib6_rules_seq_read(struct net *net);
 413 #else
 414 static inline int               fib6_rules_init(void)
 415 {
 416         return 0;
 417 }
 418 static inline void              fib6_rules_cleanup(void)
 419 {
 420         return ;
 421 }
 422 static inline bool fib6_rule_default(const struct fib_rule *rule)
 423 {
 424         return true;
 425 }
 426 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb)
 427 {
 428         return 0;
 429 }
 430 static inline unsigned int fib6_rules_seq_read(struct net *net)
 431 {
 432         return 0;
 433 }
 434 #endif
 435 #endif