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 #ifdef CONFIG_NET_NS
  69         struct net *net;
  70 #endif
  71         struct net_device *dev;
  72         struct list_head list;
  73         int     (*neigh_setup)(struct neighbour *);
  74         void    (*neigh_cleanup)(struct neighbour *);
  75         struct neigh_table *tbl;
  76
  77         void    *sysctl_table;
  78
  79         int dead;
  80         atomic_t refcnt;
  81         struct rcu_head rcu_head;
  82
  83         int     reachable_time;
  84         int     data[NEIGH_VAR_DATA_MAX];
  85         DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
  86 };
  87
  88 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
  89 {
  90         set_bit(index, p->data_state);
  91         p->data[index] = val;
  92 }
  93
  94 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
  95
  96 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
  97  * In other cases, NEIGH_VAR_SET should be used.
  98  */
  99 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
 100 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
 101
 102 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
 103 {
 104         bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
 105 }
 106
 107 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
 108 {
 109         bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
 110 }
 111
 112 struct neigh_statistics {
 113         unsigned long allocs;           /* number of allocated neighs */
 114         unsigned long destroys;         /* number of destroyed neighs */
 115         unsigned long hash_grows;       /* number of hash resizes */
 116
 117         unsigned long res_failed;       /* number of failed resolutions */
 118
 119         unsigned long lookups;          /* number of lookups */
 120         unsigned long hits;             /* number of hits (among lookups) */
 121
 122         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
 123         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
 124
 125         unsigned long periodic_gc_runs; /* number of periodic GC runs */
 126         unsigned long forced_gc_runs;   /* number of forced GC runs */
 127
 128         unsigned long unres_discards;   /* number of unresolved drops */
 129 };
 130
 131 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
 132
 133 struct neighbour {
 134         struct neighbour __rcu  *next;
 135         struct neigh_table      *tbl;
 136         struct neigh_parms      *parms;
 137         unsigned long           confirmed;
 138         unsigned long           updated;
 139         rwlock_t                lock;
 140         atomic_t                refcnt;
 141         struct sk_buff_head     arp_queue;
 142         unsigned int            arp_queue_len_bytes;
 143         struct timer_list       timer;
 144         unsigned long           used;
 145         atomic_t                probes;
 146         __u8                    flags;
 147         __u8                    nud_state;
 148         __u8                    type;
 149         __u8                    dead;
 150         seqlock_t               ha_lock;
 151         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
 152         struct hh_cache         hh;
 153         int                     (*output)(struct neighbour *, struct sk_buff *);
 154         const struct neigh_ops  *ops;
 155         struct rcu_head         rcu;
 156         struct net_device       *dev;
 157         u8                      primary_key[0];
 158 };
 159
 160 struct neigh_ops {
 161         int                     family;
 162         void                    (*solicit)(struct neighbour *, struct sk_buff *);
 163         void                    (*error_report)(struct neighbour *, struct sk_buff *);
 164         int                     (*output)(struct neighbour *, struct sk_buff *);
 165         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
 166 };
 167
 168 struct pneigh_entry {
 169         struct pneigh_entry     *next;
 170 #ifdef CONFIG_NET_NS
 171         struct net              *net;
 172 #endif
 173         struct net_device       *dev;
 174         u8                      flags;
 175         u8                      key[0];
 176 };
 177
 178 /*
 179  *      neighbour table manipulation
 180  */
 181
 182 #define NEIGH_NUM_HASH_RND      4
 183
 184 struct neigh_hash_table {
 185         struct neighbour __rcu  **hash_buckets;
 186         unsigned int            hash_shift;
 187         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
 188         struct rcu_head         rcu;
 189 };
 190
 191
 192 struct neigh_table {
 193         int                     family;
 194         int                     entry_size;
 195         int                     key_len;
 196         __be16                  protocol;
 197         __u32                   (*hash)(const void *pkey,
 198                                         const struct net_device *dev,
 199                                         __u32 *hash_rnd);
 200         bool                    (*key_eq)(const struct neighbour *, const void *pkey);
 201         int                     (*constructor)(struct neighbour *);
 202         int                     (*pconstructor)(struct pneigh_entry *);
 203         void                    (*pdestructor)(struct pneigh_entry *);
 204         void                    (*proxy_redo)(struct sk_buff *skb);
 205         char                    *id;
 206         struct neigh_parms      parms;
 207         struct list_head        parms_list;
 208         int                     gc_interval;
 209         int                     gc_thresh1;
 210         int                     gc_thresh2;
 211         int                     gc_thresh3;
 212         unsigned long           last_flush;
 213         struct delayed_work     gc_work;
 214         struct timer_list       proxy_timer;
 215         struct sk_buff_head     proxy_queue;
 216         atomic_t                entries;
 217         rwlock_t                lock;
 218         unsigned long           last_rand;
 219         struct neigh_statistics __percpu *stats;
 220         struct neigh_hash_table __rcu *nht;
 221         struct pneigh_entry     **phash_buckets;
 222 };
 223
 224 enum {
 225         NEIGH_ARP_TABLE = 0,
 226         NEIGH_ND_TABLE = 1,
 227         NEIGH_DN_TABLE = 2,
 228         NEIGH_NR_TABLES,
 229 };
 230
 231 static inline int neigh_parms_family(struct neigh_parms *p)
 232 {
 233         return p->tbl->family;
 234 }
 235
 236 #define NEIGH_PRIV_ALIGN        sizeof(long long)
 237 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
 238
 239 static inline void *neighbour_priv(const struct neighbour *n)
 240 {
 241         return (char *)n + n->tbl->entry_size;
 242 }
 243
 244 /* flags for neigh_update() */
 245 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 246 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 247 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 248 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 249 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
 250
 251
 252 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
 253 {
 254         return *(const u16 *)n->primary_key == *(const u16 *)pkey;
 255 }
 256
 257 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
 258 {
 259         return *(const u32 *)n->primary_key == *(const u32 *)pkey;
 260 }
 261
 262 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
 263 {
 264         const u32 *n32 = (const u32 *)n->primary_key;
 265         const u32 *p32 = pkey;
 266
 267         return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
 268                 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
 269 }
 270
 271 static inline struct neighbour *___neigh_lookup_noref(
 272         struct neigh_table *tbl,
 273         bool (*key_eq)(const struct neighbour *n, const void *pkey),
 274         __u32 (*hash)(const void *pkey,
 275                       const struct net_device *dev,
 276                       __u32 *hash_rnd),
 277         const void *pkey,
 278         struct net_device *dev)
 279 {
 280         struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
 281         struct neighbour *n;
 282         u32 hash_val;
 283
 284         hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
 285         for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
 286              n != NULL;
 287              n = rcu_dereference_bh(n->next)) {
 288                 if (n->dev == dev && key_eq(n, pkey))
 289                         return n;
 290         }
 291
 292         return NULL;
 293 }
 294
 295 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
 296                                                      const void *pkey,
 297                                                      struct net_device *dev)
 298 {
 299         return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
 300 }
 301
 302 void neigh_table_init(int index, struct neigh_table *tbl);
 303 int neigh_table_clear(int index, struct neigh_table *tbl);
 304 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 305                                struct net_device *dev);
 306 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
 307                                      const void *pkey);
 308 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 309                                  struct net_device *dev, bool want_ref);
 310 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 311                                              const void *pkey,
 312                                              struct net_device *dev)
 313 {
 314         return __neigh_create(tbl, pkey, dev, true);
 315 }
 316 void neigh_destroy(struct neighbour *neigh);
 317 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 318 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
 319 void __neigh_set_probe_once(struct neighbour *neigh);
 320 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 321 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 322 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 323 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 324 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 325 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 326                                                 u8 *lladdr, void *saddr,
 327                                                 struct net_device *dev);
 328
 329 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 330                                       struct neigh_table *tbl);
 331 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 332
 333 static inline
 334 struct net *neigh_parms_net(const struct neigh_parms *parms)
 335 {
 336         return read_pnet(&parms->net);
 337 }
 338
 339 unsigned long neigh_rand_reach_time(unsigned long base);
 340
 341 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 342                     struct sk_buff *skb);
 343 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 344                                    const void *key, struct net_device *dev,
 345                                    int creat);
 346 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 347                                      const void *key, struct net_device *dev);
 348 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 349                   struct net_device *dev);
 350
 351 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 352 {
 353         return read_pnet(&pneigh->net);
 354 }
 355
 356 void neigh_app_ns(struct neighbour *n);
 357 void neigh_for_each(struct neigh_table *tbl,
 358                     void (*cb)(struct neighbour *, void *), void *cookie);
 359 void __neigh_for_each_release(struct neigh_table *tbl,
 360                               int (*cb)(struct neighbour *));
 361 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
 362 void pneigh_for_each(struct neigh_table *tbl,
 363                      void (*cb)(struct pneigh_entry *));
 364
 365 struct neigh_seq_state {
 366         struct seq_net_private p;
 367         struct neigh_table *tbl;
 368         struct neigh_hash_table *nht;
 369         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 370                                 struct neighbour *n, loff_t *pos);
 371         unsigned int bucket;
 372         unsigned int flags;
 373 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 374 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 375 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 376 };
 377 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 378                       unsigned int);
 379 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 380 void neigh_seq_stop(struct seq_file *, void *);
 381
 382 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
 383                         void __user *buffer, size_t *lenp, loff_t *ppos);
 384 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
 385                                 void __user *buffer,
 386                                 size_t *lenp, loff_t *ppos);
 387 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 388                                    void __user *buffer,
 389                                    size_t *lenp, loff_t *ppos);
 390
 391 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 392                           proc_handler *proc_handler);
 393 void neigh_sysctl_unregister(struct neigh_parms *p);
 394
 395 static inline void __neigh_parms_put(struct neigh_parms *parms)
 396 {
 397         atomic_dec(&parms->refcnt);
 398 }
 399
 400 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 401 {
 402         atomic_inc(&parms->refcnt);
 403         return parms;
 404 }
 405
 406 /*
 407  *      Neighbour references
 408  */
 409
 410 static inline void neigh_release(struct neighbour *neigh)
 411 {
 412         if (atomic_dec_and_test(&neigh->refcnt))
 413                 neigh_destroy(neigh);
 414 }
 415
 416 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 417 {
 418         if (neigh)
 419                 atomic_inc(&neigh->refcnt);
 420         return neigh;
 421 }
 422
 423 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 424
 425 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 426 {
 427         unsigned long now = jiffies;
 428
 429         if (neigh->used != now)
 430                 neigh->used = now;
 431         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 432                 return __neigh_event_send(neigh, skb);
 433         return 0;
 434 }
 435
 436 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 437 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 438 {
 439         unsigned int seq, hh_alen;
 440
 441         do {
 442                 seq = read_seqbegin(&hh->hh_lock);
 443                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 444                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 445         } while (read_seqretry(&hh->hh_lock, seq));
 446         return 0;
 447 }
 448 #endif
 449
 450 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 451 {
 452         unsigned int seq;
 453         int hh_len;
 454
 455         do {
 456                 seq = read_seqbegin(&hh->hh_lock);
 457                 hh_len = hh->hh_len;
 458                 if (likely(hh_len <= HH_DATA_MOD)) {
 459                         /* this is inlined by gcc */
 460                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
 461                 } else {
 462                         int hh_alen = HH_DATA_ALIGN(hh_len);
 463
 464                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 465                 }
 466         } while (read_seqretry(&hh->hh_lock, seq));
 467
 468         skb_push(skb, hh_len);
 469         return dev_queue_xmit(skb);
 470 }
 471
 472 static inline struct neighbour *
 473 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 474 {
 475         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 476
 477         if (n || !creat)
 478                 return n;
 479
 480         n = neigh_create(tbl, pkey, dev);
 481         return IS_ERR(n) ? NULL : n;
 482 }
 483
 484 static inline struct neighbour *
 485 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 486   struct net_device *dev)
 487 {
 488         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 489
 490         if (n)
 491                 return n;
 492
 493         return neigh_create(tbl, pkey, dev);
 494 }
 495
 496 struct neighbour_cb {
 497         unsigned long sched_next;
 498         unsigned int flags;
 499 };
 500
 501 #define LOCALLY_ENQUEUED 0x1
 502
 503 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 504
 505 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 506                                      const struct net_device *dev)
 507 {
 508         unsigned int seq;
 509
 510         do {
 511                 seq = read_seqbegin(&n->ha_lock);
 512                 memcpy(dst, n->ha, dev->addr_len);
 513         } while (read_seqretry(&n->ha_lock, seq));
 514 }
 515
 516
 517 #endif