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