kernel/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_MCAST_REPROBES,
  46         NEIGH_VAR_RETRANS_TIME,
  47         NEIGH_VAR_BASE_REACHABLE_TIME,
  48         NEIGH_VAR_DELAY_PROBE_TIME,
  49         NEIGH_VAR_GC_STALETIME,
  50         NEIGH_VAR_QUEUE_LEN_BYTES,
  51         NEIGH_VAR_PROXY_QLEN,
  52         NEIGH_VAR_ANYCAST_DELAY,
  53         NEIGH_VAR_PROXY_DELAY,
  54         NEIGH_VAR_LOCKTIME,
  55 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
  56         /* Following are used as a second way to access one of the above */
  57         NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
  58         NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
  59         NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
  60         /* Following are used by "default" only */
  61         NEIGH_VAR_GC_INTERVAL,
  62         NEIGH_VAR_GC_THRESH1,
  63         NEIGH_VAR_GC_THRESH2,
  64         NEIGH_VAR_GC_THRESH3,
  65         NEIGH_VAR_MAX
  66 };
  67
  68 struct neigh_parms {
  69         possible_net_t net;
  70         struct net_device *dev;
  71         struct list_head list;
  72         int     (*neigh_setup)(struct neighbour *);
  73         void    (*neigh_cleanup)(struct neighbour *);
  74         struct neigh_table *tbl;
  75
  76         void    *sysctl_table;
  77
  78         int dead;
  79         atomic_t refcnt;
  80         struct rcu_head rcu_head;
  81
  82         int     reachable_time;
  83         int     data[NEIGH_VAR_DATA_MAX];
  84         DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
  85 };
  86
  87 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
  88 {
  89         set_bit(index, p->data_state);
  90         p->data[index] = val;
  91 }
  92
  93 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
  94
  95 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
  96  * In other cases, NEIGH_VAR_SET should be used.
  97  */
  98 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
  99 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
 100
 101 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
 102 {
 103         bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
 104 }
 105
 106 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
 107 {
 108         bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
 109 }
 110
 111 struct neigh_statistics {
 112         unsigned long allocs;           /* number of allocated neighs */
 113         unsigned long destroys;         /* number of destroyed neighs */
 114         unsigned long hash_grows;       /* number of hash resizes */
 115
 116         unsigned long res_failed;       /* number of failed resolutions */
 117
 118         unsigned long lookups;          /* number of lookups */
 119         unsigned long hits;             /* number of hits (among lookups) */
 120
 121         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
 122         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
 123
 124         unsigned long periodic_gc_runs; /* number of periodic GC runs */
 125         unsigned long forced_gc_runs;   /* number of forced GC runs */
 126
 127         unsigned long unres_discards;   /* number of unresolved drops */
 128         unsigned long table_fulls;      /* times even gc couldn't help */
 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         possible_net_t          net;
 171         struct net_device       *dev;
 172         u8                      flags;
 173         u8                      key[0];
 174 };
 175
 176 /*
 177  *      neighbour table manipulation
 178  */
 179
 180 #define NEIGH_NUM_HASH_RND      4
 181
 182 struct neigh_hash_table {
 183         struct neighbour __rcu  **hash_buckets;
 184         unsigned int            hash_shift;
 185         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
 186         struct rcu_head         rcu;
 187 };
 188
 189
 190 struct neigh_table {
 191         int                     family;
 192         int                     entry_size;
 193         int                     key_len;
 194         __be16                  protocol;
 195         __u32                   (*hash)(const void *pkey,
 196                                         const struct net_device *dev,
 197                                         __u32 *hash_rnd);
 198         bool                    (*key_eq)(const struct neighbour *, const void *pkey);
 199         int                     (*constructor)(struct neighbour *);
 200         int                     (*pconstructor)(struct pneigh_entry *);
 201         void                    (*pdestructor)(struct pneigh_entry *);
 202         void                    (*proxy_redo)(struct sk_buff *skb);
 203         char                    *id;
 204         struct neigh_parms      parms;
 205         struct list_head        parms_list;
 206         int                     gc_interval;
 207         int                     gc_thresh1;
 208         int                     gc_thresh2;
 209         int                     gc_thresh3;
 210         unsigned long           last_flush;
 211         struct delayed_work     gc_work;
 212         struct timer_list       proxy_timer;
 213         struct sk_buff_head     proxy_queue;
 214         atomic_t                entries;
 215         rwlock_t                lock;
 216         unsigned long           last_rand;
 217         struct neigh_statistics __percpu *stats;
 218         struct neigh_hash_table __rcu *nht;
 219         struct pneigh_entry     **phash_buckets;
 220 };
 221
 222 enum {
 223         NEIGH_ARP_TABLE = 0,
 224         NEIGH_ND_TABLE = 1,
 225         NEIGH_DN_TABLE = 2,
 226         NEIGH_NR_TABLES,
 227         NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
 228 };
 229
 230 static inline int neigh_parms_family(struct neigh_parms *p)
 231 {
 232         return p->tbl->family;
 233 }
 234
 235 #define NEIGH_PRIV_ALIGN        sizeof(long long)
 236 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
 237
 238 static inline void *neighbour_priv(const struct neighbour *n)
 239 {
 240         return (char *)n + n->tbl->entry_size;
 241 }
 242
 243 /* flags for neigh_update() */
 244 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 245 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 246 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 247 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 248 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
 249
 250
 251 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
 252 {
 253         return *(const u16 *)n->primary_key == *(const u16 *)pkey;
 254 }
 255
 256 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
 257 {
 258         return *(const u32 *)n->primary_key == *(const u32 *)pkey;
 259 }
 260
 261 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
 262 {
 263         const u32 *n32 = (const u32 *)n->primary_key;
 264         const u32 *p32 = pkey;
 265
 266         return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
 267                 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
 268 }
 269
 270 static inline struct neighbour *___neigh_lookup_noref(
 271         struct neigh_table *tbl,
 272         bool (*key_eq)(const struct neighbour *n, const void *pkey),
 273         __u32 (*hash)(const void *pkey,
 274                       const struct net_device *dev,
 275                       __u32 *hash_rnd),
 276         const void *pkey,
 277         struct net_device *dev)
 278 {
 279         struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
 280         struct neighbour *n;
 281         u32 hash_val;
 282
 283         hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
 284         for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
 285              n != NULL;
 286              n = rcu_dereference_bh(n->next)) {
 287                 if (n->dev == dev && key_eq(n, pkey))
 288                         return n;
 289         }
 290
 291         return NULL;
 292 }
 293
 294 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
 295                                                      const void *pkey,
 296                                                      struct net_device *dev)
 297 {
 298         return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
 299 }
 300
 301 void neigh_table_init(int index, struct neigh_table *tbl);
 302 int neigh_table_clear(int index, struct neigh_table *tbl);
 303 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 304                                struct net_device *dev);
 305 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
 306                                      const void *pkey);
 307 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 308                                  struct net_device *dev, bool want_ref);
 309 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 310                                              const void *pkey,
 311                                              struct net_device *dev)
 312 {
 313         return __neigh_create(tbl, pkey, dev, true);
 314 }
 315 void neigh_destroy(struct neighbour *neigh);
 316 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 317 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
 318 void __neigh_set_probe_once(struct neighbour *neigh);
 319 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 320 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 321 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 322 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 323 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 324 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 325                                                 u8 *lladdr, void *saddr,
 326                                                 struct net_device *dev);
 327
 328 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 329                                       struct neigh_table *tbl);
 330 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 331
 332 static inline
 333 struct net *neigh_parms_net(const struct neigh_parms *parms)
 334 {
 335         return read_pnet(&parms->net);
 336 }
 337
 338 unsigned long neigh_rand_reach_time(unsigned long base);
 339
 340 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 341                     struct sk_buff *skb);
 342 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 343                                    const void *key, struct net_device *dev,
 344                                    int creat);
 345 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 346                                      const void *key, struct net_device *dev);
 347 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 348                   struct net_device *dev);
 349
 350 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 351 {
 352         return read_pnet(&pneigh->net);
 353 }
 354
 355 void neigh_app_ns(struct neighbour *n);
 356 void neigh_for_each(struct neigh_table *tbl,
 357                     void (*cb)(struct neighbour *, void *), void *cookie);
 358 void __neigh_for_each_release(struct neigh_table *tbl,
 359                               int (*cb)(struct neighbour *));
 360 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
 361 void pneigh_for_each(struct neigh_table *tbl,
 362                      void (*cb)(struct pneigh_entry *));
 363
 364 struct neigh_seq_state {
 365         struct seq_net_private p;
 366         struct neigh_table *tbl;
 367         struct neigh_hash_table *nht;
 368         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 369                                 struct neighbour *n, loff_t *pos);
 370         unsigned int bucket;
 371         unsigned int flags;
 372 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 373 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 374 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 375 };
 376 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 377                       unsigned int);
 378 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 379 void neigh_seq_stop(struct seq_file *, void *);
 380
 381 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
 382                         void __user *buffer, size_t *lenp, loff_t *ppos);
 383 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
 384                                 void __user *buffer,
 385                                 size_t *lenp, loff_t *ppos);
 386 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 387                                    void __user *buffer,
 388                                    size_t *lenp, loff_t *ppos);
 389
 390 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 391                           proc_handler *proc_handler);
 392 void neigh_sysctl_unregister(struct neigh_parms *p);
 393
 394 static inline void __neigh_parms_put(struct neigh_parms *parms)
 395 {
 396         atomic_dec(&parms->refcnt);
 397 }
 398
 399 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 400 {
 401         atomic_inc(&parms->refcnt);
 402         return parms;
 403 }
 404
 405 /*
 406  *      Neighbour references
 407  */
 408
 409 static inline void neigh_release(struct neighbour *neigh)
 410 {
 411         if (atomic_dec_and_test(&neigh->refcnt))
 412                 neigh_destroy(neigh);
 413 }
 414
 415 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 416 {
 417         if (neigh)
 418                 atomic_inc(&neigh->refcnt);
 419         return neigh;
 420 }
 421
 422 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 423
 424 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 425 {
 426         unsigned long now = jiffies;
 427
 428         if (neigh->used != now)
 429                 neigh->used = now;
 430         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 431                 return __neigh_event_send(neigh, skb);
 432         return 0;
 433 }
 434
 435 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 436 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 437 {
 438         unsigned int seq, hh_alen;
 439
 440         do {
 441                 seq = read_seqbegin(&hh->hh_lock);
 442                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 443                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 444         } while (read_seqretry(&hh->hh_lock, seq));
 445         return 0;
 446 }
 447 #endif
 448
 449 static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
 450 {
 451         unsigned int seq;
 452         int hh_len;
 453
 454         do {
 455                 seq = read_seqbegin(&hh->hh_lock);
 456                 hh_len = hh->hh_len;
 457                 if (likely(hh_len <= HH_DATA_MOD)) {
 458                         /* this is inlined by gcc */
 459                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
 460                 } else {
 461                         int hh_alen = HH_DATA_ALIGN(hh_len);
 462
 463                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 464                 }
 465         } while (read_seqretry(&hh->hh_lock, seq));
 466
 467         skb_push(skb, hh_len);
 468         return dev_queue_xmit(skb);
 469 }
 470
 471 static inline struct neighbour *
 472 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 473 {
 474         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 475
 476         if (n || !creat)
 477                 return n;
 478
 479         n = neigh_create(tbl, pkey, dev);
 480         return IS_ERR(n) ? NULL : n;
 481 }
 482
 483 static inline struct neighbour *
 484 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 485   struct net_device *dev)
 486 {
 487         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 488
 489         if (n)
 490                 return n;
 491
 492         return neigh_create(tbl, pkey, dev);
 493 }
 494
 495 struct neighbour_cb {
 496         unsigned long sched_next;
 497         unsigned int flags;
 498 };
 499
 500 #define LOCALLY_ENQUEUED 0x1
 501
 502 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 503
 504 static inline void neigh_ha_snapshot(char *dst, struct neighbour *n,
 505                                      const struct net_device *dev)
 506 {
 507         unsigned int seq;
 508
 509         do {
 510                 seq = read_seqbegin(&n->ha_lock);
 511                 memcpy(dst, n->ha, dev->addr_len);
 512         } while (read_seqretry(&n->ha_lock, seq));
 513 }
 514
 515
 516 #endif