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/refcount.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/seq_file.h>
  25 #include <linux/bitmap.h>
  26
  27 #include <linux/err.h>
  28 #include <linux/sysctl.h>
  29 #include <linux/workqueue.h>
  30 #include <net/rtnetlink.h>
  31
  32 /*
  33  * NUD stands for "neighbor unreachability detection"
  34  */
  35
  36 #define NUD_IN_TIMER    (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
  37 #define NUD_VALID       (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
  38 #define NUD_CONNECTED   (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
  39
  40 struct neighbour;
  41
  42 enum {
  43         NEIGH_VAR_MCAST_PROBES,
  44         NEIGH_VAR_UCAST_PROBES,
  45         NEIGH_VAR_APP_PROBES,
  46         NEIGH_VAR_MCAST_REPROBES,
  47         NEIGH_VAR_RETRANS_TIME,
  48         NEIGH_VAR_BASE_REACHABLE_TIME,
  49         NEIGH_VAR_DELAY_PROBE_TIME,
  50         NEIGH_VAR_GC_STALETIME,
  51         NEIGH_VAR_QUEUE_LEN_BYTES,
  52         NEIGH_VAR_PROXY_QLEN,
  53         NEIGH_VAR_ANYCAST_DELAY,
  54         NEIGH_VAR_PROXY_DELAY,
  55         NEIGH_VAR_LOCKTIME,
  56 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
  57         /* Following are used as a second way to access one of the above */
  58         NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
  59         NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
  60         NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
  61         /* Following are used by "default" only */
  62         NEIGH_VAR_GC_INTERVAL,
  63         NEIGH_VAR_GC_THRESH1,
  64         NEIGH_VAR_GC_THRESH2,
  65         NEIGH_VAR_GC_THRESH3,
  66         NEIGH_VAR_MAX
  67 };
  68
  69 struct neigh_parms {
  70         possible_net_t net;
  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         refcount_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         unsigned long table_fulls;      /* times even gc couldn't help */
 130 };
 131
 132 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
 133
 134 struct neighbour {
 135         struct neighbour __rcu  *next;
 136         struct neigh_table      *tbl;
 137         struct neigh_parms      *parms;
 138         unsigned long           confirmed;
 139         unsigned long           updated;
 140         rwlock_t                lock;
 141         refcount_t              refcnt;
 142         struct sk_buff_head     arp_queue;
 143         unsigned int            arp_queue_len_bytes;
 144         struct timer_list       timer;
 145         unsigned long           used;
 146         atomic_t                probes;
 147         __u8                    flags;
 148         __u8                    nud_state;
 149         __u8                    type;
 150         __u8                    dead;
 151         seqlock_t               ha_lock;
 152         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
 153         struct hh_cache         hh;
 154         int                     (*output)(struct neighbour *, struct sk_buff *);
 155         const struct neigh_ops  *ops;
 156         struct rcu_head         rcu;
 157         struct net_device       *dev;
 158         u8                      primary_key[0];
 159 } __randomize_layout;
 160
 161 struct neigh_ops {
 162         int                     family;
 163         void                    (*solicit)(struct neighbour *, struct sk_buff *);
 164         void                    (*error_report)(struct neighbour *, struct sk_buff *);
 165         int                     (*output)(struct neighbour *, struct sk_buff *);
 166         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
 167 };
 168
 169 struct pneigh_entry {
 170         struct pneigh_entry     *next;
 171         possible_net_t          net;
 172         struct net_device       *dev;
 173         u8                      flags;
 174         u8                      key[0];
 175 };
 176
 177 /*
 178  *      neighbour table manipulation
 179  */
 180
 181 #define NEIGH_NUM_HASH_RND      4
 182
 183 struct neigh_hash_table {
 184         struct neighbour __rcu  **hash_buckets;
 185         unsigned int            hash_shift;
 186         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
 187         struct rcu_head         rcu;
 188 };
 189
 190
 191 struct neigh_table {
 192         int                     family;
 193         int                     entry_size;
 194         int                     key_len;
 195         __be16                  protocol;
 196         __u32                   (*hash)(const void *pkey,
 197                                         const struct net_device *dev,
 198                                         __u32 *hash_rnd);
 199         bool                    (*key_eq)(const struct neighbour *, const void *pkey);
 200         int                     (*constructor)(struct neighbour *);
 201         int                     (*pconstructor)(struct pneigh_entry *);
 202         void                    (*pdestructor)(struct pneigh_entry *);
 203         void                    (*proxy_redo)(struct sk_buff *skb);
 204         char                    *id;
 205         struct neigh_parms      parms;
 206         struct list_head        parms_list;
 207         int                     gc_interval;
 208         int                     gc_thresh1;
 209         int                     gc_thresh2;
 210         int                     gc_thresh3;
 211         unsigned long           last_flush;
 212         struct delayed_work     gc_work;
 213         struct timer_list       proxy_timer;
 214         struct sk_buff_head     proxy_queue;
 215         atomic_t                entries;
 216         rwlock_t                lock;
 217         unsigned long           last_rand;
 218         struct neigh_statistics __percpu *stats;
 219         struct neigh_hash_table __rcu *nht;
 220         struct pneigh_entry     **phash_buckets;
 221 };
 222
 223 enum {
 224         NEIGH_ARP_TABLE = 0,
 225         NEIGH_ND_TABLE = 1,
 226         NEIGH_DN_TABLE = 2,
 227         NEIGH_NR_TABLES,
 228         NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
 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                  u32 nlmsg_pid);
 320 void __neigh_set_probe_once(struct neighbour *neigh);
 321 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
 322 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 323 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 324 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 325 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 326 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 327 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 328                                                 u8 *lladdr, void *saddr,
 329                                                 struct net_device *dev);
 330
 331 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 332                                       struct neigh_table *tbl);
 333 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 334
 335 static inline
 336 struct net *neigh_parms_net(const struct neigh_parms *parms)
 337 {
 338         return read_pnet(&parms->net);
 339 }
 340
 341 unsigned long neigh_rand_reach_time(unsigned long base);
 342
 343 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 344                     struct sk_buff *skb);
 345 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 346                                    const void *key, struct net_device *dev,
 347                                    int creat);
 348 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 349                                      const void *key, struct net_device *dev);
 350 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 351                   struct net_device *dev);
 352
 353 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 354 {
 355         return read_pnet(&pneigh->net);
 356 }
 357
 358 void neigh_app_ns(struct neighbour *n);
 359 void neigh_for_each(struct neigh_table *tbl,
 360                     void (*cb)(struct neighbour *, void *), void *cookie);
 361 void __neigh_for_each_release(struct neigh_table *tbl,
 362                               int (*cb)(struct neighbour *));
 363 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
 364 void pneigh_for_each(struct neigh_table *tbl,
 365                      void (*cb)(struct pneigh_entry *));
 366
 367 struct neigh_seq_state {
 368         struct seq_net_private p;
 369         struct neigh_table *tbl;
 370         struct neigh_hash_table *nht;
 371         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 372                                 struct neighbour *n, loff_t *pos);
 373         unsigned int bucket;
 374         unsigned int flags;
 375 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 376 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 377 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 378 };
 379 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 380                       unsigned int);
 381 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 382 void neigh_seq_stop(struct seq_file *, void *);
 383
 384 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
 385                         void __user *buffer, size_t *lenp, loff_t *ppos);
 386 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
 387                                 void __user *buffer,
 388                                 size_t *lenp, loff_t *ppos);
 389 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 390                                    void __user *buffer,
 391                                    size_t *lenp, loff_t *ppos);
 392
 393 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 394                           proc_handler *proc_handler);
 395 void neigh_sysctl_unregister(struct neigh_parms *p);
 396
 397 static inline void __neigh_parms_put(struct neigh_parms *parms)
 398 {
 399         refcount_dec(&parms->refcnt);
 400 }
 401
 402 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 403 {
 404         refcount_inc(&parms->refcnt);
 405         return parms;
 406 }
 407
 408 /*
 409  *      Neighbour references
 410  */
 411
 412 static inline void neigh_release(struct neighbour *neigh)
 413 {
 414         if (refcount_dec_and_test(&neigh->refcnt))
 415                 neigh_destroy(neigh);
 416 }
 417
 418 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 419 {
 420         if (neigh)
 421                 refcount_inc(&neigh->refcnt);
 422         return neigh;
 423 }
 424
 425 #define neigh_hold(n)   refcount_inc(&(n)->refcnt)
 426
 427 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 428 {
 429         unsigned long now = jiffies;
 430
 431         if (neigh->used != now)
 432                 neigh->used = now;
 433         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 434                 return __neigh_event_send(neigh, skb);
 435         return 0;
 436 }
 437
 438 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 439 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 440 {
 441         unsigned int seq, hh_alen;
 442
 443         do {
 444                 seq = read_seqbegin(&hh->hh_lock);
 445                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 446                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 447         } while (read_seqretry(&hh->hh_lock, seq));
 448         return 0;
 449 }
 450 #endif
 451
 452 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 453 {
 454         unsigned int seq;
 455         unsigned int hh_len;
 456
 457         do {
 458                 seq = read_seqbegin(&hh->hh_lock);
 459                 hh_len = hh->hh_len;
 460                 if (likely(hh_len <= HH_DATA_MOD)) {
 461                         /* this is inlined by gcc */
 462                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
 463                 } else {
 464                         unsigned int hh_alen = HH_DATA_ALIGN(hh_len);
 465
 466                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 467                 }
 468         } while (read_seqretry(&hh->hh_lock, seq));
 469
 470         skb_push(skb, hh_len);
 471         return dev_queue_xmit(skb);
 472 }
 473
 474 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb)
 475 {
 476         const struct hh_cache *hh = &n->hh;
 477
 478         if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
 479                 return neigh_hh_output(hh, skb);
 480         else
 481                 return n->output(n, skb);
 482 }
 483
 484 static inline struct neighbour *
 485 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 486 {
 487         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 488
 489         if (n || !creat)
 490                 return n;
 491
 492         n = neigh_create(tbl, pkey, dev);
 493         return IS_ERR(n) ? NULL : n;
 494 }
 495
 496 static inline struct neighbour *
 497 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 498   struct net_device *dev)
 499 {
 500         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 501
 502         if (n)
 503                 return n;
 504
 505         return neigh_create(tbl, pkey, dev);
 506 }
 507
 508 struct neighbour_cb {
 509         unsigned long sched_next;
 510         unsigned int flags;
 511 };
 512
 513 #define LOCALLY_ENQUEUED 0x1
 514
 515 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 516
 517 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 518                                      const struct net_device *dev)
 519 {
 520         unsigned int seq;
 521
 522         do {
 523                 seq = read_seqbegin(&n->ha_lock);
 524                 memcpy(dst, n->ha, dev->addr_len);
 525         } while (read_seqretry(&n->ha_lock, seq));
 526 }
 527
 528
 529 #endif