include/net/neighbour.h

   1 #ifndef _NET_NEIGHBOUR_H
   2 #define _NET_NEIGHBOUR_H
   3
   4 #include <linux/neighbour.h>
   5
   6 /*
   7  *      Generic neighbour manipulation
   8  *
   9  *      Authors:
  10  *      Pedro Roque             <roque@di.fc.ul.pt>
  11  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
  12  *
  13  *      Changes:
  14  *
  15  *      Harald Welte:           <laforge@gnumonks.org>
  16  *              - Add neighbour cache statistics like rtstat
  17  */
  18
  19 #include <linux/atomic.h>
  20 #include <linux/netdevice.h>
  21 #include <linux/skbuff.h>
  22 #include <linux/rcupdate.h>
  23 #include <linux/seq_file.h>
  24
  25 #include <linux/err.h>
  26 #include <linux/sysctl.h>
  27 #include <linux/workqueue.h>
  28 #include <net/rtnetlink.h>
  29
  30 /*
  31  * NUD stands for "neighbor unreachability detection"
  32  */
  33
  34 #define NUD_IN_TIMER    (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
  35 #define NUD_VALID       (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
  36 #define NUD_CONNECTED   (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
  37
  38 struct neighbour;
  39
  40 enum {
  41         NEIGH_VAR_MCAST_PROBES,
  42         NEIGH_VAR_UCAST_PROBES,
  43         NEIGH_VAR_APP_PROBES,
  44         NEIGH_VAR_RETRANS_TIME,
  45         NEIGH_VAR_BASE_REACHABLE_TIME,
  46         NEIGH_VAR_DELAY_PROBE_TIME,
  47         NEIGH_VAR_GC_STALETIME,
  48         NEIGH_VAR_QUEUE_LEN_BYTES,
  49         NEIGH_VAR_PROXY_QLEN,
  50         NEIGH_VAR_ANYCAST_DELAY,
  51         NEIGH_VAR_PROXY_DELAY,
  52         NEIGH_VAR_LOCKTIME,
  53 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
  54         /* Following are used as a second way to access one of the above */
  55         NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
  56         NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
  57         NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
  58         /* Following are used by "default" only */
  59         NEIGH_VAR_GC_INTERVAL,
  60         NEIGH_VAR_GC_THRESH1,
  61         NEIGH_VAR_GC_THRESH2,
  62         NEIGH_VAR_GC_THRESH3,
  63         NEIGH_VAR_MAX
  64 };
  65
  66 struct neigh_parms {
  67 #ifdef CONFIG_NET_NS
  68         struct net *net;
  69 #endif
  70         struct net_device *dev;
  71         struct neigh_parms *next;
  72         int     (*neigh_setup)(struct neighbour *);
  73         void    (*neigh_cleanup)(struct neighbour *);
  74         struct neigh_table *tbl;
  75
  76         void    *sysctl_table;
  77
  78         int dead;
  79         atomic_t refcnt;
  80         struct rcu_head rcu_head;
  81
  82         int     reachable_time;
  83         int     data[NEIGH_VAR_DATA_MAX];
  84 };
  85
  86 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
  87 {
  88         p->data[index] = val;
  89 }
  90
  91 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
  92 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
  93
  94 struct neigh_statistics {
  95         unsigned long allocs;           /* number of allocated neighs */
  96         unsigned long destroys;         /* number of destroyed neighs */
  97         unsigned long hash_grows;       /* number of hash resizes */
  98
  99         unsigned long res_failed;       /* number of failed resolutions */
 100
 101         unsigned long lookups;          /* number of lookups */
 102         unsigned long hits;             /* number of hits (among lookups) */
 103
 104         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
 105         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
 106
 107         unsigned long periodic_gc_runs; /* number of periodic GC runs */
 108         unsigned long forced_gc_runs;   /* number of forced GC runs */
 109
 110         unsigned long unres_discards;   /* number of unresolved drops */
 111 };
 112
 113 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
 114
 115 struct neighbour {
 116         struct neighbour __rcu  *next;
 117         struct neigh_table      *tbl;
 118         struct neigh_parms      *parms;
 119         unsigned long           confirmed;
 120         unsigned long           updated;
 121         rwlock_t                lock;
 122         atomic_t                refcnt;
 123         struct sk_buff_head     arp_queue;
 124         unsigned int            arp_queue_len_bytes;
 125         struct timer_list       timer;
 126         unsigned long           used;
 127         atomic_t                probes;
 128         __u8                    flags;
 129         __u8                    nud_state;
 130         __u8                    type;
 131         __u8                    dead;
 132         seqlock_t               ha_lock;
 133         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
 134         struct hh_cache         hh;
 135         int                     (*output)(struct neighbour *, struct sk_buff *);
 136         const struct neigh_ops  *ops;
 137         struct rcu_head         rcu;
 138         struct net_device       *dev;
 139         u8                      primary_key[0];
 140 };
 141
 142 struct neigh_ops {
 143         int                     family;
 144         void                    (*solicit)(struct neighbour *, struct sk_buff *);
 145         void                    (*error_report)(struct neighbour *, struct sk_buff *);
 146         int                     (*output)(struct neighbour *, struct sk_buff *);
 147         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
 148 };
 149
 150 struct pneigh_entry {
 151         struct pneigh_entry     *next;
 152 #ifdef CONFIG_NET_NS
 153         struct net              *net;
 154 #endif
 155         struct net_device       *dev;
 156         u8                      flags;
 157         u8                      key[0];
 158 };
 159
 160 /*
 161  *      neighbour table manipulation
 162  */
 163
 164 #define NEIGH_NUM_HASH_RND      4
 165
 166 struct neigh_hash_table {
 167         struct neighbour __rcu  **hash_buckets;
 168         unsigned int            hash_shift;
 169         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
 170         struct rcu_head         rcu;
 171 };
 172
 173
 174 struct neigh_table {
 175         struct neigh_table      *next;
 176         int                     family;
 177         int                     entry_size;
 178         int                     key_len;
 179         __u32                   (*hash)(const void *pkey,
 180                                         const struct net_device *dev,
 181                                         __u32 *hash_rnd);
 182         int                     (*constructor)(struct neighbour *);
 183         int                     (*pconstructor)(struct pneigh_entry *);
 184         void                    (*pdestructor)(struct pneigh_entry *);
 185         void                    (*proxy_redo)(struct sk_buff *skb);
 186         char                    *id;
 187         struct neigh_parms      parms;
 188         /* HACK. gc_* should follow parms without a gap! */
 189         int                     gc_interval;
 190         int                     gc_thresh1;
 191         int                     gc_thresh2;
 192         int                     gc_thresh3;
 193         unsigned long           last_flush;
 194         struct delayed_work     gc_work;
 195         struct timer_list       proxy_timer;
 196         struct sk_buff_head     proxy_queue;
 197         atomic_t                entries;
 198         rwlock_t                lock;
 199         unsigned long           last_rand;
 200         struct neigh_statistics __percpu *stats;
 201         struct neigh_hash_table __rcu *nht;
 202         struct pneigh_entry     **phash_buckets;
 203 };
 204
 205 #define NEIGH_PRIV_ALIGN        sizeof(long long)
 206 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
 207
 208 static inline void *neighbour_priv(const struct neighbour *n)
 209 {
 210         return (char *)n + n->tbl->entry_size;
 211 }
 212
 213 /* flags for neigh_update() */
 214 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 215 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 216 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 217 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 218 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
 219
 220 void neigh_table_init(struct neigh_table *tbl);
 221 int neigh_table_clear(struct neigh_table *tbl);
 222 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 223                                struct net_device *dev);
 224 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
 225                                      const void *pkey);
 226 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 227                                  struct net_device *dev, bool want_ref);
 228 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 229                                              const void *pkey,
 230                                              struct net_device *dev)
 231 {
 232         return __neigh_create(tbl, pkey, dev, true);
 233 }
 234 void neigh_destroy(struct neighbour *neigh);
 235 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 236 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
 237 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 238 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 239 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 240 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 241 int neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
 242 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 243 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 244                                                 u8 *lladdr, void *saddr,
 245                                                 struct net_device *dev);
 246
 247 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 248                                       struct neigh_table *tbl);
 249 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 250
 251 static inline
 252 struct net *neigh_parms_net(const struct neigh_parms *parms)
 253 {
 254         return read_pnet(&parms->net);
 255 }
 256
 257 unsigned long neigh_rand_reach_time(unsigned long base);
 258
 259 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 260                     struct sk_buff *skb);
 261 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 262                                    const void *key, struct net_device *dev,
 263                                    int creat);
 264 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 265                                      const void *key, struct net_device *dev);
 266 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 267                   struct net_device *dev);
 268
 269 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 270 {
 271         return read_pnet(&pneigh->net);
 272 }
 273
 274 void neigh_app_ns(struct neighbour *n);
 275 void neigh_for_each(struct neigh_table *tbl,
 276                     void (*cb)(struct neighbour *, void *), void *cookie);
 277 void __neigh_for_each_release(struct neigh_table *tbl,
 278                               int (*cb)(struct neighbour *));
 279 void pneigh_for_each(struct neigh_table *tbl,
 280                      void (*cb)(struct pneigh_entry *));
 281
 282 struct neigh_seq_state {
 283         struct seq_net_private p;
 284         struct neigh_table *tbl;
 285         struct neigh_hash_table *nht;
 286         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 287                                 struct neighbour *n, loff_t *pos);
 288         unsigned int bucket;
 289         unsigned int flags;
 290 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 291 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 292 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 293 };
 294 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 295                       unsigned int);
 296 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 297 void neigh_seq_stop(struct seq_file *, void *);
 298
 299 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 300                           char *p_name, proc_handler *proc_handler);
 301 void neigh_sysctl_unregister(struct neigh_parms *p);
 302
 303 static inline void __neigh_parms_put(struct neigh_parms *parms)
 304 {
 305         atomic_dec(&parms->refcnt);
 306 }
 307
 308 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 309 {
 310         atomic_inc(&parms->refcnt);
 311         return parms;
 312 }
 313
 314 /*
 315  *      Neighbour references
 316  */
 317
 318 static inline void neigh_release(struct neighbour *neigh)
 319 {
 320         if (atomic_dec_and_test(&neigh->refcnt))
 321                 neigh_destroy(neigh);
 322 }
 323
 324 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 325 {
 326         if (neigh)
 327                 atomic_inc(&neigh->refcnt);
 328         return neigh;
 329 }
 330
 331 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 332
 333 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 334 {
 335         unsigned long now = jiffies;
 336
 337         if (neigh->used != now)
 338                 neigh->used = now;
 339         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 340                 return __neigh_event_send(neigh, skb);
 341         return 0;
 342 }
 343
 344 #ifdef CONFIG_BRIDGE_NETFILTER
 345 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 346 {
 347         unsigned int seq, hh_alen;
 348
 349         do {
 350                 seq = read_seqbegin(&hh->hh_lock);
 351                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 352                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 353         } while (read_seqretry(&hh->hh_lock, seq));
 354         return 0;
 355 }
 356 #endif
 357
 358 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 359 {
 360         unsigned int seq;
 361         int hh_len;
 362
 363         do {
 364                 seq = read_seqbegin(&hh->hh_lock);
 365                 hh_len = hh->hh_len;
 366                 if (likely(hh_len <= HH_DATA_MOD)) {
 367                         /* this is inlined by gcc */
 368                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
 369                 } else {
 370                         int hh_alen = HH_DATA_ALIGN(hh_len);
 371
 372                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 373                 }
 374         } while (read_seqretry(&hh->hh_lock, seq));
 375
 376         skb_push(skb, hh_len);
 377         return dev_queue_xmit(skb);
 378 }
 379
 380 static inline struct neighbour *
 381 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 382 {
 383         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 384
 385         if (n || !creat)
 386                 return n;
 387
 388         n = neigh_create(tbl, pkey, dev);
 389         return IS_ERR(n) ? NULL : n;
 390 }
 391
 392 static inline struct neighbour *
 393 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 394   struct net_device *dev)
 395 {
 396         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 397
 398         if (n)
 399                 return n;
 400
 401         return neigh_create(tbl, pkey, dev);
 402 }
 403
 404 struct neighbour_cb {
 405         unsigned long sched_next;
 406         unsigned int flags;
 407 };
 408
 409 #define LOCALLY_ENQUEUED 0x1
 410
 411 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 412
 413 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 414                                      const struct net_device *dev)
 415 {
 416         unsigned int seq;
 417
 418         do {
 419                 seq = read_seqbegin(&n->ha_lock);
 420                 memcpy(dst, n->ha, dev->addr_len);
 421         } while (read_seqretry(&n->ha_lock, seq));
 422 }
 423 #endif