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