include/net/neighbour.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _NET_NEIGHBOUR_H
   3 #define _NET_NEIGHBOUR_H
   4
   5 #include <linux/neighbour.h>
   6
   7 /*
   8  *      Generic neighbour manipulation
   9  *
  10  *      Authors:
  11  *      Pedro Roque             <roque@di.fc.ul.pt>
  12  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
  13  *
  14  *      Changes:
  15  *
  16  *      Harald Welte:           <laforge@gnumonks.org>
  17  *              - Add neighbour cache statistics like rtstat
  18  */
  19
  20 #include <linux/atomic.h>
  21 #include <linux/refcount.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/skbuff.h>
  24 #include <linux/rcupdate.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/bitmap.h>
  27
  28 #include <linux/err.h>
  29 #include <linux/sysctl.h>
  30 #include <linux/workqueue.h>
  31 #include <net/rtnetlink.h>
  32
  33 /*
  34  * NUD stands for "neighbor unreachability detection"
  35  */
  36
  37 #define NUD_IN_TIMER    (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
  38 #define NUD_VALID       (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
  39 #define NUD_CONNECTED   (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
  40
  41 struct neighbour;
  42
  43 enum {
  44         NEIGH_VAR_MCAST_PROBES,
  45         NEIGH_VAR_UCAST_PROBES,
  46         NEIGH_VAR_APP_PROBES,
  47         NEIGH_VAR_MCAST_REPROBES,
  48         NEIGH_VAR_RETRANS_TIME,
  49         NEIGH_VAR_BASE_REACHABLE_TIME,
  50         NEIGH_VAR_DELAY_PROBE_TIME,
  51         NEIGH_VAR_INTERVAL_PROBE_TIME_MS,
  52         NEIGH_VAR_GC_STALETIME,
  53         NEIGH_VAR_QUEUE_LEN_BYTES,
  54         NEIGH_VAR_PROXY_QLEN,
  55         NEIGH_VAR_ANYCAST_DELAY,
  56         NEIGH_VAR_PROXY_DELAY,
  57         NEIGH_VAR_LOCKTIME,
  58 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
  59         /* Following are used as a second way to access one of the above */
  60         NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
  61         NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
  62         NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
  63         /* Following are used by "default" only */
  64         NEIGH_VAR_GC_INTERVAL,
  65         NEIGH_VAR_GC_THRESH1,
  66         NEIGH_VAR_GC_THRESH2,
  67         NEIGH_VAR_GC_THRESH3,
  68         NEIGH_VAR_MAX
  69 };
  70
  71 struct neigh_parms {
  72         possible_net_t net;
  73         struct net_device *dev;
  74         netdevice_tracker dev_tracker;
  75         struct list_head list;
  76         int     (*neigh_setup)(struct neighbour *);
  77         struct neigh_table *tbl;
  78
  79         void    *sysctl_table;
  80
  81         int dead;
  82         refcount_t refcnt;
  83         struct rcu_head rcu_head;
  84
  85         int     reachable_time;
  86         int     data[NEIGH_VAR_DATA_MAX];
  87         DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
  88 };
  89
  90 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
  91 {
  92         set_bit(index, p->data_state);
  93         p->data[index] = val;
  94 }
  95
  96 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
  97
  98 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
  99  * In other cases, NEIGH_VAR_SET should be used.
 100  */
 101 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
 102 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
 103
 104 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
 105 {
 106         bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
 107 }
 108
 109 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
 110 {
 111         bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
 112 }
 113
 114 struct neigh_statistics {
 115         unsigned long allocs;           /* number of allocated neighs */
 116         unsigned long destroys;         /* number of destroyed neighs */
 117         unsigned long hash_grows;       /* number of hash resizes */
 118
 119         unsigned long res_failed;       /* number of failed resolutions */
 120
 121         unsigned long lookups;          /* number of lookups */
 122         unsigned long hits;             /* number of hits (among lookups) */
 123
 124         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
 125         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
 126
 127         unsigned long periodic_gc_runs; /* number of periodic GC runs */
 128         unsigned long forced_gc_runs;   /* number of forced GC runs */
 129
 130         unsigned long unres_discards;   /* number of unresolved drops */
 131         unsigned long table_fulls;      /* times even gc couldn't help */
 132 };
 133
 134 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
 135
 136 struct neighbour {
 137         struct neighbour __rcu  *next;
 138         struct neigh_table      *tbl;
 139         struct neigh_parms      *parms;
 140         unsigned long           confirmed;
 141         unsigned long           updated;
 142         rwlock_t                lock;
 143         refcount_t              refcnt;
 144         unsigned int            arp_queue_len_bytes;
 145         struct sk_buff_head     arp_queue;
 146         struct timer_list       timer;
 147         unsigned long           used;
 148         atomic_t                probes;
 149         u8                      nud_state;
 150         u8                      type;
 151         u8                      dead;
 152         u8                      protocol;
 153         u32                     flags;
 154         seqlock_t               ha_lock;
 155         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
 156         struct hh_cache         hh;
 157         int                     (*output)(struct neighbour *, struct sk_buff *);
 158         const struct neigh_ops  *ops;
 159         struct list_head        gc_list;
 160         struct list_head        managed_list;
 161         struct rcu_head         rcu;
 162         struct net_device       *dev;
 163         netdevice_tracker       dev_tracker;
 164         u8                      primary_key[0];
 165 } __randomize_layout;
 166
 167 struct neigh_ops {
 168         int                     family;
 169         void                    (*solicit)(struct neighbour *, struct sk_buff *);
 170         void                    (*error_report)(struct neighbour *, struct sk_buff *);
 171         int                     (*output)(struct neighbour *, struct sk_buff *);
 172         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
 173 };
 174
 175 struct pneigh_entry {
 176         struct pneigh_entry     *next;
 177         possible_net_t          net;
 178         struct net_device       *dev;
 179         netdevice_tracker       dev_tracker;
 180         u32                     flags;
 181         u8                      protocol;
 182         u8                      key[];
 183 };
 184
 185 /*
 186  *      neighbour table manipulation
 187  */
 188
 189 #define NEIGH_NUM_HASH_RND      4
 190
 191 struct neigh_hash_table {
 192         struct neighbour __rcu  **hash_buckets;
 193         unsigned int            hash_shift;
 194         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
 195         struct rcu_head         rcu;
 196 };
 197
 198
 199 struct neigh_table {
 200         int                     family;
 201         unsigned int            entry_size;
 202         unsigned int            key_len;
 203         __be16                  protocol;
 204         __u32                   (*hash)(const void *pkey,
 205                                         const struct net_device *dev,
 206                                         __u32 *hash_rnd);
 207         bool                    (*key_eq)(const struct neighbour *, const void *pkey);
 208         int                     (*constructor)(struct neighbour *);
 209         int                     (*pconstructor)(struct pneigh_entry *);
 210         void                    (*pdestructor)(struct pneigh_entry *);
 211         void                    (*proxy_redo)(struct sk_buff *skb);
 212         int                     (*is_multicast)(const void *pkey);
 213         bool                    (*allow_add)(const struct net_device *dev,
 214                                              struct netlink_ext_ack *extack);
 215         char                    *id;
 216         struct neigh_parms      parms;
 217         struct list_head        parms_list;
 218         int                     gc_interval;
 219         int                     gc_thresh1;
 220         int                     gc_thresh2;
 221         int                     gc_thresh3;
 222         unsigned long           last_flush;
 223         struct delayed_work     gc_work;
 224         struct delayed_work     managed_work;
 225         struct timer_list       proxy_timer;
 226         struct sk_buff_head     proxy_queue;
 227         atomic_t                entries;
 228         atomic_t                gc_entries;
 229         struct list_head        gc_list;
 230         struct list_head        managed_list;
 231         rwlock_t                lock;
 232         unsigned long           last_rand;
 233         struct neigh_statistics __percpu *stats;
 234         struct neigh_hash_table __rcu *nht;
 235         struct pneigh_entry     **phash_buckets;
 236 };
 237
 238 enum {
 239         NEIGH_ARP_TABLE = 0,
 240         NEIGH_ND_TABLE = 1,
 241         NEIGH_DN_TABLE = 2,
 242         NEIGH_NR_TABLES,
 243         NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
 244 };
 245
 246 static inline int neigh_parms_family(struct neigh_parms *p)
 247 {
 248         return p->tbl->family;
 249 }
 250
 251 #define NEIGH_PRIV_ALIGN        sizeof(long long)
 252 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
 253
 254 static inline void *neighbour_priv(const struct neighbour *n)
 255 {
 256         return (char *)n + n->tbl->entry_size;
 257 }
 258
 259 /* flags for neigh_update() */
 260 #define NEIGH_UPDATE_F_OVERRIDE                 BIT(0)
 261 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            BIT(1)
 262 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        BIT(2)
 263 #define NEIGH_UPDATE_F_USE                      BIT(3)
 264 #define NEIGH_UPDATE_F_MANAGED                  BIT(4)
 265 #define NEIGH_UPDATE_F_EXT_LEARNED              BIT(5)
 266 #define NEIGH_UPDATE_F_ISROUTER                 BIT(6)
 267 #define NEIGH_UPDATE_F_ADMIN                    BIT(7)
 268
 269 /* In-kernel representation for NDA_FLAGS_EXT flags: */
 270 #define NTF_OLD_MASK            0xff
 271 #define NTF_EXT_SHIFT           8
 272 #define NTF_EXT_MASK            (NTF_EXT_MANAGED)
 273
 274 #define NTF_MANAGED             (NTF_EXT_MANAGED << NTF_EXT_SHIFT)
 275
 276 extern const struct nla_policy nda_policy[];
 277
 278 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
 279 {
 280         return *(const u16 *)n->primary_key == *(const u16 *)pkey;
 281 }
 282
 283 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
 284 {
 285         return *(const u32 *)n->primary_key == *(const u32 *)pkey;
 286 }
 287
 288 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
 289 {
 290         const u32 *n32 = (const u32 *)n->primary_key;
 291         const u32 *p32 = pkey;
 292
 293         return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
 294                 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
 295 }
 296
 297 static inline struct neighbour *___neigh_lookup_noref(
 298         struct neigh_table *tbl,
 299         bool (*key_eq)(const struct neighbour *n, const void *pkey),
 300         __u32 (*hash)(const void *pkey,
 301                       const struct net_device *dev,
 302                       __u32 *hash_rnd),
 303         const void *pkey,
 304         struct net_device *dev)
 305 {
 306         struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
 307         struct neighbour *n;
 308         u32 hash_val;
 309
 310         hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
 311         for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
 312              n != NULL;
 313              n = rcu_dereference_bh(n->next)) {
 314                 if (n->dev == dev && key_eq(n, pkey))
 315                         return n;
 316         }
 317
 318         return NULL;
 319 }
 320
 321 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
 322                                                      const void *pkey,
 323                                                      struct net_device *dev)
 324 {
 325         return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
 326 }
 327
 328 static inline void neigh_confirm(struct neighbour *n)
 329 {
 330         if (n) {
 331                 unsigned long now = jiffies;
 332
 333                 /* avoid dirtying neighbour */
 334                 if (READ_ONCE(n->confirmed) != now)
 335                         WRITE_ONCE(n->confirmed, now);
 336         }
 337 }
 338
 339 void neigh_table_init(int index, struct neigh_table *tbl);
 340 int neigh_table_clear(int index, struct neigh_table *tbl);
 341 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 342                                struct net_device *dev);
 343 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
 344                                      const void *pkey);
 345 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 346                                  struct net_device *dev, bool want_ref);
 347 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 348                                              const void *pkey,
 349                                              struct net_device *dev)
 350 {
 351         return __neigh_create(tbl, pkey, dev, true);
 352 }
 353 void neigh_destroy(struct neighbour *neigh);
 354 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
 355                        const bool immediate_ok);
 356 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
 357                  u32 nlmsg_pid);
 358 void __neigh_set_probe_once(struct neighbour *neigh);
 359 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
 360 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 361 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 362 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
 363 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 364 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 365 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 366 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 367                                                 u8 *lladdr, void *saddr,
 368                                                 struct net_device *dev);
 369
 370 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 371                                       struct neigh_table *tbl);
 372 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 373
 374 static inline
 375 struct net *neigh_parms_net(const struct neigh_parms *parms)
 376 {
 377         return read_pnet(&parms->net);
 378 }
 379
 380 unsigned long neigh_rand_reach_time(unsigned long base);
 381
 382 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 383                     struct sk_buff *skb);
 384 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 385                                    const void *key, struct net_device *dev,
 386                                    int creat);
 387 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 388                                      const void *key, struct net_device *dev);
 389 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 390                   struct net_device *dev);
 391
 392 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 393 {
 394         return read_pnet(&pneigh->net);
 395 }
 396
 397 void neigh_app_ns(struct neighbour *n);
 398 void neigh_for_each(struct neigh_table *tbl,
 399                     void (*cb)(struct neighbour *, void *), void *cookie);
 400 void __neigh_for_each_release(struct neigh_table *tbl,
 401                               int (*cb)(struct neighbour *));
 402 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
 403 void pneigh_for_each(struct neigh_table *tbl,
 404                      void (*cb)(struct pneigh_entry *));
 405
 406 struct neigh_seq_state {
 407         struct seq_net_private p;
 408         struct neigh_table *tbl;
 409         struct neigh_hash_table *nht;
 410         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 411                                 struct neighbour *n, loff_t *pos);
 412         unsigned int bucket;
 413         unsigned int flags;
 414 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 415 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 416 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 417 };
 418 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 419                       unsigned int);
 420 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 421 void neigh_seq_stop(struct seq_file *, void *);
 422
 423 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
 424                         void *buffer, size_t *lenp, loff_t *ppos);
 425 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
 426                                 void *buffer,
 427                                 size_t *lenp, loff_t *ppos);
 428 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 429                                    void *buffer, size_t *lenp, loff_t *ppos);
 430
 431 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 432                           proc_handler *proc_handler);
 433 void neigh_sysctl_unregister(struct neigh_parms *p);
 434
 435 static inline void __neigh_parms_put(struct neigh_parms *parms)
 436 {
 437         refcount_dec(&parms->refcnt);
 438 }
 439
 440 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 441 {
 442         refcount_inc(&parms->refcnt);
 443         return parms;
 444 }
 445
 446 /*
 447  *      Neighbour references
 448  */
 449
 450 static inline void neigh_release(struct neighbour *neigh)
 451 {
 452         if (refcount_dec_and_test(&neigh->refcnt))
 453                 neigh_destroy(neigh);
 454 }
 455
 456 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 457 {
 458         if (neigh)
 459                 refcount_inc(&neigh->refcnt);
 460         return neigh;
 461 }
 462
 463 #define neigh_hold(n)   refcount_inc(&(n)->refcnt)
 464
 465 static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
 466                                                   struct sk_buff *skb,
 467                                                   const bool immediate_ok)
 468 {
 469         unsigned long now = jiffies;
 470
 471         if (READ_ONCE(neigh->used) != now)
 472                 WRITE_ONCE(neigh->used, now);
 473         if (!(neigh->nud_state & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
 474                 return __neigh_event_send(neigh, skb, immediate_ok);
 475         return 0;
 476 }
 477
 478 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 479 {
 480         return neigh_event_send_probe(neigh, skb, true);
 481 }
 482
 483 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 484 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 485 {
 486         unsigned int seq, hh_alen;
 487
 488         do {
 489                 seq = read_seqbegin(&hh->hh_lock);
 490                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 491                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 492         } while (read_seqretry(&hh->hh_lock, seq));
 493         return 0;
 494 }
 495 #endif
 496
 497 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 498 {
 499         unsigned int hh_alen = 0;
 500         unsigned int seq;
 501         unsigned int hh_len;
 502
 503         do {
 504                 seq = read_seqbegin(&hh->hh_lock);
 505                 hh_len = READ_ONCE(hh->hh_len);
 506                 if (likely(hh_len <= HH_DATA_MOD)) {
 507                         hh_alen = HH_DATA_MOD;
 508
 509                         /* skb_push() would proceed silently if we have room for
 510                          * the unaligned size but not for the aligned size:
 511                          * check headroom explicitly.
 512                          */
 513                         if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
 514                                 /* this is inlined by gcc */
 515                                 memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
 516                                        HH_DATA_MOD);
 517                         }
 518                 } else {
 519                         hh_alen = HH_DATA_ALIGN(hh_len);
 520
 521                         if (likely(skb_headroom(skb) >= hh_alen)) {
 522                                 memcpy(skb->data - hh_alen, hh->hh_data,
 523                                        hh_alen);
 524                         }
 525                 }
 526         } while (read_seqretry(&hh->hh_lock, seq));
 527
 528         if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
 529                 kfree_skb(skb);
 530                 return NET_XMIT_DROP;
 531         }
 532
 533         __skb_push(skb, hh_len);
 534         return dev_queue_xmit(skb);
 535 }
 536
 537 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
 538                                bool skip_cache)
 539 {
 540         const struct hh_cache *hh = &n->hh;
 541
 542         /* n->nud_state and hh->hh_len could be changed under us.
 543          * neigh_hh_output() is taking care of the race later.
 544          */
 545         if (!skip_cache &&
 546             (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
 547             READ_ONCE(hh->hh_len))
 548                 return neigh_hh_output(hh, skb);
 549
 550         return n->output(n, skb);
 551 }
 552
 553 static inline struct neighbour *
 554 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 555 {
 556         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 557
 558         if (n || !creat)
 559                 return n;
 560
 561         n = neigh_create(tbl, pkey, dev);
 562         return IS_ERR(n) ? NULL : n;
 563 }
 564
 565 static inline struct neighbour *
 566 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 567   struct net_device *dev)
 568 {
 569         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 570
 571         if (n)
 572                 return n;
 573
 574         return neigh_create(tbl, pkey, dev);
 575 }
 576
 577 struct neighbour_cb {
 578         unsigned long sched_next;
 579         unsigned int flags;
 580 };
 581
 582 #define LOCALLY_ENQUEUED 0x1
 583
 584 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 585
 586 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 587                                      const struct net_device *dev)
 588 {
 589         unsigned int seq;
 590
 591         do {
 592                 seq = read_seqbegin(&n->ha_lock);
 593                 memcpy(dst, n->ha, dev->addr_len);
 594         } while (read_seqretry(&n->ha_lock, seq));
 595 }
 596
 597 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
 598                                           int *notify)
 599 {
 600         u8 ndm_flags = 0;
 601
 602         ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
 603         if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
 604                 if (ndm_flags & NTF_ROUTER)
 605                         neigh->flags |= NTF_ROUTER;
 606                 else
 607                         neigh->flags &= ~NTF_ROUTER;
 608                 *notify = 1;
 609         }
 610 }
 611 #endif