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         u32                     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_eq32(const struct neighbour *n, const void *pkey)
 280 {
 281         return *(const u32 *)n->primary_key == *(const u32 *)pkey;
 282 }
 283
 284 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
 285 {
 286         const u32 *n32 = (const u32 *)n->primary_key;
 287         const u32 *p32 = pkey;
 288
 289         return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
 290                 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
 291 }
 292
 293 static inline struct neighbour *___neigh_lookup_noref(
 294         struct neigh_table *tbl,
 295         bool (*key_eq)(const struct neighbour *n, const void *pkey),
 296         __u32 (*hash)(const void *pkey,
 297                       const struct net_device *dev,
 298                       __u32 *hash_rnd),
 299         const void *pkey,
 300         struct net_device *dev)
 301 {
 302         struct neigh_hash_table *nht = rcu_dereference(tbl->nht);
 303         struct neighbour *n;
 304         u32 hash_val;
 305
 306         hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
 307         for (n = rcu_dereference(nht->hash_buckets[hash_val]);
 308              n != NULL;
 309              n = rcu_dereference(n->next)) {
 310                 if (n->dev == dev && key_eq(n, pkey))
 311                         return n;
 312         }
 313
 314         return NULL;
 315 }
 316
 317 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
 318                                                      const void *pkey,
 319                                                      struct net_device *dev)
 320 {
 321         return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
 322 }
 323
 324 static inline void neigh_confirm(struct neighbour *n)
 325 {
 326         if (n) {
 327                 unsigned long now = jiffies;
 328
 329                 /* avoid dirtying neighbour */
 330                 if (READ_ONCE(n->confirmed) != now)
 331                         WRITE_ONCE(n->confirmed, now);
 332         }
 333 }
 334
 335 void neigh_table_init(int index, struct neigh_table *tbl);
 336 int neigh_table_clear(int index, struct neigh_table *tbl);
 337 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 338                                struct net_device *dev);
 339 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 340                                  struct net_device *dev, bool want_ref);
 341 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 342                                              const void *pkey,
 343                                              struct net_device *dev)
 344 {
 345         return __neigh_create(tbl, pkey, dev, true);
 346 }
 347 void neigh_destroy(struct neighbour *neigh);
 348 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
 349                        const bool immediate_ok);
 350 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
 351                  u32 nlmsg_pid);
 352 void __neigh_set_probe_once(struct neighbour *neigh);
 353 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
 354 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 355 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 356 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
 357 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 358 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 359 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 360 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 361                                                 u8 *lladdr, void *saddr,
 362                                                 struct net_device *dev);
 363
 364 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 365                                       struct neigh_table *tbl);
 366 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 367
 368 static inline
 369 struct net *neigh_parms_net(const struct neigh_parms *parms)
 370 {
 371         return read_pnet(&parms->net);
 372 }
 373
 374 unsigned long neigh_rand_reach_time(unsigned long base);
 375
 376 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 377                     struct sk_buff *skb);
 378 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 379                                    const void *key, struct net_device *dev,
 380                                    int creat);
 381 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 382                                      const void *key, struct net_device *dev);
 383 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 384                   struct net_device *dev);
 385
 386 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 387 {
 388         return read_pnet(&pneigh->net);
 389 }
 390
 391 void neigh_app_ns(struct neighbour *n);
 392 void neigh_for_each(struct neigh_table *tbl,
 393                     void (*cb)(struct neighbour *, void *), void *cookie);
 394 void __neigh_for_each_release(struct neigh_table *tbl,
 395                               int (*cb)(struct neighbour *));
 396 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
 397
 398 struct neigh_seq_state {
 399         struct seq_net_private p;
 400         struct neigh_table *tbl;
 401         struct neigh_hash_table *nht;
 402         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 403                                 struct neighbour *n, loff_t *pos);
 404         unsigned int bucket;
 405         unsigned int flags;
 406 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 407 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 408 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 409 };
 410 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 411                       unsigned int);
 412 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 413 void neigh_seq_stop(struct seq_file *, void *);
 414
 415 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
 416                         void *buffer, size_t *lenp, loff_t *ppos);
 417 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
 418                                 void *buffer,
 419                                 size_t *lenp, loff_t *ppos);
 420 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 421                                    void *buffer, size_t *lenp, loff_t *ppos);
 422
 423 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 424                           proc_handler *proc_handler);
 425 void neigh_sysctl_unregister(struct neigh_parms *p);
 426
 427 static inline void __neigh_parms_put(struct neigh_parms *parms)
 428 {
 429         refcount_dec(&parms->refcnt);
 430 }
 431
 432 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 433 {
 434         refcount_inc(&parms->refcnt);
 435         return parms;
 436 }
 437
 438 /*
 439  *      Neighbour references
 440  */
 441
 442 static inline void neigh_release(struct neighbour *neigh)
 443 {
 444         if (refcount_dec_and_test(&neigh->refcnt))
 445                 neigh_destroy(neigh);
 446 }
 447
 448 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 449 {
 450         if (neigh)
 451                 refcount_inc(&neigh->refcnt);
 452         return neigh;
 453 }
 454
 455 #define neigh_hold(n)   refcount_inc(&(n)->refcnt)
 456
 457 static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
 458                                                   struct sk_buff *skb,
 459                                                   const bool immediate_ok)
 460 {
 461         unsigned long now = jiffies;
 462
 463         if (READ_ONCE(neigh->used) != now)
 464                 WRITE_ONCE(neigh->used, now);
 465         if (!(READ_ONCE(neigh->nud_state) & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
 466                 return __neigh_event_send(neigh, skb, immediate_ok);
 467         return 0;
 468 }
 469
 470 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 471 {
 472         return neigh_event_send_probe(neigh, skb, true);
 473 }
 474
 475 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 476 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 477 {
 478         unsigned int seq, hh_alen;
 479
 480         do {
 481                 seq = read_seqbegin(&hh->hh_lock);
 482                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 483                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 484         } while (read_seqretry(&hh->hh_lock, seq));
 485         return 0;
 486 }
 487 #endif
 488
 489 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 490 {
 491         unsigned int hh_alen = 0;
 492         unsigned int seq;
 493         unsigned int hh_len;
 494
 495         do {
 496                 seq = read_seqbegin(&hh->hh_lock);
 497                 hh_len = READ_ONCE(hh->hh_len);
 498                 if (likely(hh_len <= HH_DATA_MOD)) {
 499                         hh_alen = HH_DATA_MOD;
 500
 501                         /* skb_push() would proceed silently if we have room for
 502                          * the unaligned size but not for the aligned size:
 503                          * check headroom explicitly.
 504                          */
 505                         if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
 506                                 /* this is inlined by gcc */
 507                                 memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
 508                                        HH_DATA_MOD);
 509                         }
 510                 } else {
 511                         hh_alen = HH_DATA_ALIGN(hh_len);
 512
 513                         if (likely(skb_headroom(skb) >= hh_alen)) {
 514                                 memcpy(skb->data - hh_alen, hh->hh_data,
 515                                        hh_alen);
 516                         }
 517                 }
 518         } while (read_seqretry(&hh->hh_lock, seq));
 519
 520         if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
 521                 kfree_skb(skb);
 522                 return NET_XMIT_DROP;
 523         }
 524
 525         __skb_push(skb, hh_len);
 526         return dev_queue_xmit(skb);
 527 }
 528
 529 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
 530                                bool skip_cache)
 531 {
 532         const struct hh_cache *hh = &n->hh;
 533
 534         /* n->nud_state and hh->hh_len could be changed under us.
 535          * neigh_hh_output() is taking care of the race later.
 536          */
 537         if (!skip_cache &&
 538             (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
 539             READ_ONCE(hh->hh_len))
 540                 return neigh_hh_output(hh, skb);
 541
 542         return n->output(n, skb);
 543 }
 544
 545 static inline struct neighbour *
 546 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 547 {
 548         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 549
 550         if (n || !creat)
 551                 return n;
 552
 553         n = neigh_create(tbl, pkey, dev);
 554         return IS_ERR(n) ? NULL : n;
 555 }
 556
 557 static inline struct neighbour *
 558 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 559   struct net_device *dev)
 560 {
 561         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 562
 563         if (n)
 564                 return n;
 565
 566         return neigh_create(tbl, pkey, dev);
 567 }
 568
 569 struct neighbour_cb {
 570         unsigned long sched_next;
 571         unsigned int flags;
 572 };
 573
 574 #define LOCALLY_ENQUEUED 0x1
 575
 576 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 577
 578 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 579                                      const struct net_device *dev)
 580 {
 581         unsigned int seq;
 582
 583         do {
 584                 seq = read_seqbegin(&n->ha_lock);
 585                 memcpy(dst, n->ha, dev->addr_len);
 586         } while (read_seqretry(&n->ha_lock, seq));
 587 }
 588
 589 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
 590                                           int *notify)
 591 {
 592         u8 ndm_flags = 0;
 593
 594         ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
 595         if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
 596                 if (ndm_flags & NTF_ROUTER)
 597                         neigh->flags |= NTF_ROUTER;
 598                 else
 599                         neigh->flags &= ~NTF_ROUTER;
 600                 *notify = 1;
 601         }
 602 }
 603 #endif