include/net/neighbour.h

   1 #ifndef _NET_NEIGHBOUR_H
   2 #define _NET_NEIGHBOUR_H
   3
   4 #include <linux/neighbour.h>
   5
   6 /*
   7  *      Generic neighbour manipulation
   8  *
   9  *      Authors:
  10  *      Pedro Roque             <roque@di.fc.ul.pt>
  11  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
  12  *
  13  *      Changes:
  14  *
  15  *      Harald Welte:           <laforge@gnumonks.org>
  16  *              - Add neighbour cache statistics like rtstat
  17  */
  18
  19 #include <linux/atomic.h>
  20 #include <linux/netdevice.h>
  21 #include <linux/skbuff.h>
  22 #include <linux/rcupdate.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/bitmap.h>
  25
  26 #include <linux/err.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/workqueue.h>
  29 #include <net/rtnetlink.h>
  30
  31 /*
  32  * NUD stands for "neighbor unreachability detection"
  33  */
  34
  35 #define NUD_IN_TIMER    (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
  36 #define NUD_VALID       (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
  37 #define NUD_CONNECTED   (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
  38
  39 struct neighbour;
  40
  41 enum {
  42         NEIGH_VAR_MCAST_PROBES,
  43         NEIGH_VAR_UCAST_PROBES,
  44         NEIGH_VAR_APP_PROBES,
  45         NEIGH_VAR_RETRANS_TIME,
  46         NEIGH_VAR_BASE_REACHABLE_TIME,
  47         NEIGH_VAR_DELAY_PROBE_TIME,
  48         NEIGH_VAR_GC_STALETIME,
  49         NEIGH_VAR_QUEUE_LEN_BYTES,
  50         NEIGH_VAR_PROXY_QLEN,
  51         NEIGH_VAR_ANYCAST_DELAY,
  52         NEIGH_VAR_PROXY_DELAY,
  53         NEIGH_VAR_LOCKTIME,
  54 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
  55         /* Following are used as a second way to access one of the above */
  56         NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
  57         NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
  58         NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
  59         /* Following are used by "default" only */
  60         NEIGH_VAR_GC_INTERVAL,
  61         NEIGH_VAR_GC_THRESH1,
  62         NEIGH_VAR_GC_THRESH2,
  63         NEIGH_VAR_GC_THRESH3,
  64         NEIGH_VAR_MAX
  65 };
  66
  67 struct neigh_parms {
  68         possible_net_t net;
  69         struct net_device *dev;
  70         struct list_head list;
  71         int     (*neigh_setup)(struct neighbour *);
  72         void    (*neigh_cleanup)(struct neighbour *);
  73         struct neigh_table *tbl;
  74
  75         void    *sysctl_table;
  76
  77         int dead;
  78         atomic_t refcnt;
  79         struct rcu_head rcu_head;
  80
  81         int     reachable_time;
  82         int     data[NEIGH_VAR_DATA_MAX];
  83         DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
  84 };
  85
  86 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
  87 {
  88         set_bit(index, p->data_state);
  89         p->data[index] = val;
  90 }
  91
  92 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
  93
  94 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
  95  * In other cases, NEIGH_VAR_SET should be used.
  96  */
  97 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
  98 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
  99
 100 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
 101 {
 102         bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
 103 }
 104
 105 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
 106 {
 107         bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
 108 }
 109
 110 struct neigh_statistics {
 111         unsigned long allocs;           /* number of allocated neighs */
 112         unsigned long destroys;         /* number of destroyed neighs */
 113         unsigned long hash_grows;       /* number of hash resizes */
 114
 115         unsigned long res_failed;       /* number of failed resolutions */
 116
 117         unsigned long lookups;          /* number of lookups */
 118         unsigned long hits;             /* number of hits (among lookups) */
 119
 120         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
 121         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
 122
 123         unsigned long periodic_gc_runs; /* number of periodic GC runs */
 124         unsigned long forced_gc_runs;   /* number of forced GC runs */
 125
 126         unsigned long unres_discards;   /* number of unresolved drops */
 127 };
 128
 129 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
 130
 131 struct neighbour {
 132         struct neighbour __rcu  *next;
 133         struct neigh_table      *tbl;
 134         struct neigh_parms      *parms;
 135         unsigned long           confirmed;
 136         unsigned long           updated;
 137         rwlock_t                lock;
 138         atomic_t                refcnt;
 139         struct sk_buff_head     arp_queue;
 140         unsigned int            arp_queue_len_bytes;
 141         struct timer_list       timer;
 142         unsigned long           used;
 143         atomic_t                probes;
 144         __u8                    flags;
 145         __u8                    nud_state;
 146         __u8                    type;
 147         __u8                    dead;
 148         seqlock_t               ha_lock;
 149         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
 150         struct hh_cache         hh;
 151         int                     (*output)(struct neighbour *, struct sk_buff *);
 152         const struct neigh_ops  *ops;
 153         struct rcu_head         rcu;
 154         struct net_device       *dev;
 155         u8                      primary_key[0];
 156 };
 157
 158 struct neigh_ops {
 159         int                     family;
 160         void                    (*solicit)(struct neighbour *, struct sk_buff *);
 161         void                    (*error_report)(struct neighbour *, struct sk_buff *);
 162         int                     (*output)(struct neighbour *, struct sk_buff *);
 163         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
 164 };
 165
 166 struct pneigh_entry {
 167         struct pneigh_entry     *next;
 168         possible_net_t          net;
 169         struct net_device       *dev;
 170         u8                      flags;
 171         u8                      key[0];
 172 };
 173
 174 /*
 175  *      neighbour table manipulation
 176  */
 177
 178 #define NEIGH_NUM_HASH_RND      4
 179
 180 struct neigh_hash_table {
 181         struct neighbour __rcu  **hash_buckets;
 182         unsigned int            hash_shift;
 183         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
 184         struct rcu_head         rcu;
 185 };
 186
 187
 188 struct neigh_table {
 189         int                     family;
 190         int                     entry_size;
 191         int                     key_len;
 192         __be16                  protocol;
 193         __u32                   (*hash)(const void *pkey,
 194                                         const struct net_device *dev,
 195                                         __u32 *hash_rnd);
 196         bool                    (*key_eq)(const struct neighbour *, const void *pkey);
 197         int                     (*constructor)(struct neighbour *);
 198         int                     (*pconstructor)(struct pneigh_entry *);
 199         void                    (*pdestructor)(struct pneigh_entry *);
 200         void                    (*proxy_redo)(struct sk_buff *skb);
 201         char                    *id;
 202         struct neigh_parms      parms;
 203         struct list_head        parms_list;
 204         int                     gc_interval;
 205         int                     gc_thresh1;
 206         int                     gc_thresh2;
 207         int                     gc_thresh3;
 208         unsigned long           last_flush;
 209         struct delayed_work     gc_work;
 210         struct timer_list       proxy_timer;
 211         struct sk_buff_head     proxy_queue;
 212         atomic_t                entries;
 213         rwlock_t                lock;
 214         unsigned long           last_rand;
 215         struct neigh_statistics __percpu *stats;
 216         struct neigh_hash_table __rcu *nht;
 217         struct pneigh_entry     **phash_buckets;
 218 };
 219
 220 enum {
 221         NEIGH_ARP_TABLE = 0,
 222         NEIGH_ND_TABLE = 1,
 223         NEIGH_DN_TABLE = 2,
 224         NEIGH_NR_TABLES,
 225         NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
 226 };
 227
 228 static inline int neigh_parms_family(struct neigh_parms *p)
 229 {
 230         return p->tbl->family;
 231 }
 232
 233 #define NEIGH_PRIV_ALIGN        sizeof(long long)
 234 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
 235
 236 static inline void *neighbour_priv(const struct neighbour *n)
 237 {
 238         return (char *)n + n->tbl->entry_size;
 239 }
 240
 241 /* flags for neigh_update() */
 242 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 243 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 244 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 245 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 246 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
 247
 248
 249 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
 250 {
 251         return *(const u16 *)n->primary_key == *(const u16 *)pkey;
 252 }
 253
 254 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
 255 {
 256         return *(const u32 *)n->primary_key == *(const u32 *)pkey;
 257 }
 258
 259 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
 260 {
 261         const u32 *n32 = (const u32 *)n->primary_key;
 262         const u32 *p32 = pkey;
 263
 264         return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
 265                 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
 266 }
 267
 268 static inline struct neighbour *___neigh_lookup_noref(
 269         struct neigh_table *tbl,
 270         bool (*key_eq)(const struct neighbour *n, const void *pkey),
 271         __u32 (*hash)(const void *pkey,
 272                       const struct net_device *dev,
 273                       __u32 *hash_rnd),
 274         const void *pkey,
 275         struct net_device *dev)
 276 {
 277         struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
 278         struct neighbour *n;
 279         u32 hash_val;
 280
 281         hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
 282         for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
 283              n != NULL;
 284              n = rcu_dereference_bh(n->next)) {
 285                 if (n->dev == dev && key_eq(n, pkey))
 286                         return n;
 287         }
 288
 289         return NULL;
 290 }
 291
 292 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
 293                                                      const void *pkey,
 294                                                      struct net_device *dev)
 295 {
 296         return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
 297 }
 298
 299 void neigh_table_init(int index, struct neigh_table *tbl);
 300 int neigh_table_clear(int index, struct neigh_table *tbl);
 301 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 302                                struct net_device *dev);
 303 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
 304                                      const void *pkey);
 305 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 306                                  struct net_device *dev, bool want_ref);
 307 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 308                                              const void *pkey,
 309                                              struct net_device *dev)
 310 {
 311         return __neigh_create(tbl, pkey, dev, true);
 312 }
 313 void neigh_destroy(struct neighbour *neigh);
 314 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 315 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
 316 void __neigh_set_probe_once(struct neighbour *neigh);
 317 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 318 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 319 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 320 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 321 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 322 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 323                                                 u8 *lladdr, void *saddr,
 324                                                 struct net_device *dev);
 325
 326 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 327                                       struct neigh_table *tbl);
 328 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 329
 330 static inline
 331 struct net *neigh_parms_net(const struct neigh_parms *parms)
 332 {
 333         return read_pnet(&parms->net);
 334 }
 335
 336 unsigned long neigh_rand_reach_time(unsigned long base);
 337
 338 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 339                     struct sk_buff *skb);
 340 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 341                                    const void *key, struct net_device *dev,
 342                                    int creat);
 343 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 344                                      const void *key, struct net_device *dev);
 345 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 346                   struct net_device *dev);
 347
 348 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 349 {
 350         return read_pnet(&pneigh->net);
 351 }
 352
 353 void neigh_app_ns(struct neighbour *n);
 354 void neigh_for_each(struct neigh_table *tbl,
 355                     void (*cb)(struct neighbour *, void *), void *cookie);
 356 void __neigh_for_each_release(struct neigh_table *tbl,
 357                               int (*cb)(struct neighbour *));
 358 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
 359 void pneigh_for_each(struct neigh_table *tbl,
 360                      void (*cb)(struct pneigh_entry *));
 361
 362 struct neigh_seq_state {
 363         struct seq_net_private p;
 364         struct neigh_table *tbl;
 365         struct neigh_hash_table *nht;
 366         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 367                                 struct neighbour *n, loff_t *pos);
 368         unsigned int bucket;
 369         unsigned int flags;
 370 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 371 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 372 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 373 };
 374 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 375                       unsigned int);
 376 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 377 void neigh_seq_stop(struct seq_file *, void *);
 378
 379 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
 380                         void __user *buffer, size_t *lenp, loff_t *ppos);
 381 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
 382                                 void __user *buffer,
 383                                 size_t *lenp, loff_t *ppos);
 384 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 385                                    void __user *buffer,
 386                                    size_t *lenp, loff_t *ppos);
 387
 388 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 389                           proc_handler *proc_handler);
 390 void neigh_sysctl_unregister(struct neigh_parms *p);
 391
 392 static inline void __neigh_parms_put(struct neigh_parms *parms)
 393 {
 394         atomic_dec(&parms->refcnt);
 395 }
 396
 397 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 398 {
 399         atomic_inc(&parms->refcnt);
 400         return parms;
 401 }
 402
 403 /*
 404  *      Neighbour references
 405  */
 406
 407 static inline void neigh_release(struct neighbour *neigh)
 408 {
 409         if (atomic_dec_and_test(&neigh->refcnt))
 410                 neigh_destroy(neigh);
 411 }
 412
 413 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 414 {
 415         if (neigh)
 416                 atomic_inc(&neigh->refcnt);
 417         return neigh;
 418 }
 419
 420 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 421
 422 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 423 {
 424         unsigned long now = jiffies;
 425
 426         if (neigh->used != now)
 427                 neigh->used = now;
 428         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 429                 return __neigh_event_send(neigh, skb);
 430         return 0;
 431 }
 432
 433 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 434 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 435 {
 436         unsigned int seq, hh_alen;
 437
 438         do {
 439                 seq = read_seqbegin(&hh->hh_lock);
 440                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 441                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 442         } while (read_seqretry(&hh->hh_lock, seq));
 443         return 0;
 444 }
 445 #endif
 446
 447 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 448 {
 449         unsigned int seq;
 450         int hh_len;
 451
 452         do {
 453                 seq = read_seqbegin(&hh->hh_lock);
 454                 hh_len = hh->hh_len;
 455                 if (likely(hh_len <= HH_DATA_MOD)) {
 456                         /* this is inlined by gcc */
 457                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
 458                 } else {
 459                         int hh_alen = HH_DATA_ALIGN(hh_len);
 460
 461                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 462                 }
 463         } while (read_seqretry(&hh->hh_lock, seq));
 464
 465         skb_push(skb, hh_len);
 466         return dev_queue_xmit(skb);
 467 }
 468
 469 static inline struct neighbour *
 470 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 471 {
 472         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 473
 474         if (n || !creat)
 475                 return n;
 476
 477         n = neigh_create(tbl, pkey, dev);
 478         return IS_ERR(n) ? NULL : n;
 479 }
 480
 481 static inline struct neighbour *
 482 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 483   struct net_device *dev)
 484 {
 485         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 486
 487         if (n)
 488                 return n;
 489
 490         return neigh_create(tbl, pkey, dev);
 491 }
 492
 493 struct neighbour_cb {
 494         unsigned long sched_next;
 495         unsigned int flags;
 496 };
 497
 498 #define LOCALLY_ENQUEUED 0x1
 499
 500 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 501
 502 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 503                                      const struct net_device *dev)
 504 {
 505         unsigned int seq;
 506
 507         do {
 508                 seq = read_seqbegin(&n->ha_lock);
 509                 memcpy(dst, n->ha, dev->addr_len);
 510         } while (read_seqretry(&n->ha_lock, seq));
 511 }
 512
 513
 514 #endif