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 struct neigh_parms {
  41 #ifdef CONFIG_NET_NS
  42         struct net *net;
  43 #endif
  44         struct net_device *dev;
  45         struct neigh_parms *next;
  46         int     (*neigh_setup)(struct neighbour *);
  47         void    (*neigh_cleanup)(struct neighbour *);
  48         struct neigh_table *tbl;
  49
  50         void    *sysctl_table;
  51
  52         int dead;
  53         atomic_t refcnt;
  54         struct rcu_head rcu_head;
  55
  56         int     base_reachable_time;
  57         int     retrans_time;
  58         int     gc_staletime;
  59         int     reachable_time;
  60         int     delay_probe_time;
  61
  62         int     queue_len_bytes;
  63         int     ucast_probes;
  64         int     app_probes;
  65         int     mcast_probes;
  66         int     anycast_delay;
  67         int     proxy_delay;
  68         int     proxy_qlen;
  69         int     locktime;
  70 };
  71
  72 struct neigh_statistics {
  73         unsigned long allocs;           /* number of allocated neighs */
  74         unsigned long destroys;         /* number of destroyed neighs */
  75         unsigned long hash_grows;       /* number of hash resizes */
  76
  77         unsigned long res_failed;       /* number of failed resolutions */
  78
  79         unsigned long lookups;          /* number of lookups */
  80         unsigned long hits;             /* number of hits (among lookups) */
  81
  82         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
  83         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
  84
  85         unsigned long periodic_gc_runs; /* number of periodic GC runs */
  86         unsigned long forced_gc_runs;   /* number of forced GC runs */
  87
  88         unsigned long unres_discards;   /* number of unresolved drops */
  89 };
  90
  91 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
  92
  93 struct neighbour {
  94         struct neighbour __rcu  *next;
  95         struct neigh_table      *tbl;
  96         struct neigh_parms      *parms;
  97         unsigned long           confirmed;
  98         unsigned long           updated;
  99         rwlock_t                lock;
 100         atomic_t                refcnt;
 101         struct sk_buff_head     arp_queue;
 102         unsigned int            arp_queue_len_bytes;
 103         struct timer_list       timer;
 104         unsigned long           used;
 105         atomic_t                probes;
 106         __u8                    flags;
 107         __u8                    nud_state;
 108         __u8                    type;
 109         __u8                    dead;
 110         seqlock_t               ha_lock;
 111         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
 112         struct hh_cache         hh;
 113         int                     (*output)(struct neighbour *, struct sk_buff *);
 114         const struct neigh_ops  *ops;
 115         struct rcu_head         rcu;
 116         struct net_device       *dev;
 117         u8                      primary_key[0];
 118 };
 119
 120 struct neigh_ops {
 121         int                     family;
 122         void                    (*solicit)(struct neighbour *, struct sk_buff *);
 123         void                    (*error_report)(struct neighbour *, struct sk_buff *);
 124         int                     (*output)(struct neighbour *, struct sk_buff *);
 125         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
 126 };
 127
 128 struct pneigh_entry {
 129         struct pneigh_entry     *next;
 130 #ifdef CONFIG_NET_NS
 131         struct net              *net;
 132 #endif
 133         struct net_device       *dev;
 134         u8                      flags;
 135         u8                      key[0];
 136 };
 137
 138 /*
 139  *      neighbour table manipulation
 140  */
 141
 142 #define NEIGH_NUM_HASH_RND      4
 143
 144 struct neigh_hash_table {
 145         struct neighbour __rcu  **hash_buckets;
 146         unsigned int            hash_shift;
 147         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
 148         struct rcu_head         rcu;
 149 };
 150
 151
 152 struct neigh_table {
 153         struct neigh_table      *next;
 154         int                     family;
 155         int                     entry_size;
 156         int                     key_len;
 157         __u32                   (*hash)(const void *pkey,
 158                                         const struct net_device *dev,
 159                                         __u32 *hash_rnd);
 160         int                     (*constructor)(struct neighbour *);
 161         int                     (*pconstructor)(struct pneigh_entry *);
 162         void                    (*pdestructor)(struct pneigh_entry *);
 163         void                    (*proxy_redo)(struct sk_buff *skb);
 164         char                    *id;
 165         struct neigh_parms      parms;
 166         /* HACK. gc_* should follow parms without a gap! */
 167         int                     gc_interval;
 168         int                     gc_thresh1;
 169         int                     gc_thresh2;
 170         int                     gc_thresh3;
 171         unsigned long           last_flush;
 172         struct delayed_work     gc_work;
 173         struct timer_list       proxy_timer;
 174         struct sk_buff_head     proxy_queue;
 175         atomic_t                entries;
 176         rwlock_t                lock;
 177         unsigned long           last_rand;
 178         struct neigh_statistics __percpu *stats;
 179         struct neigh_hash_table __rcu *nht;
 180         struct pneigh_entry     **phash_buckets;
 181 };
 182
 183 #define NEIGH_PRIV_ALIGN        sizeof(long long)
 184 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
 185
 186 static inline void *neighbour_priv(const struct neighbour *n)
 187 {
 188         return (char *)n + n->tbl->entry_size;
 189 }
 190
 191 /* flags for neigh_update() */
 192 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 193 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 194 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 195 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 196 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
 197
 198 void neigh_table_init(struct neigh_table *tbl);
 199 int neigh_table_clear(struct neigh_table *tbl);
 200 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 201                                struct net_device *dev);
 202 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
 203                                      const void *pkey);
 204 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 205                                  struct net_device *dev, bool want_ref);
 206 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 207                                              const void *pkey,
 208                                              struct net_device *dev)
 209 {
 210         return __neigh_create(tbl, pkey, dev, true);
 211 }
 212 void neigh_destroy(struct neighbour *neigh);
 213 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 214 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
 215 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 216 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 217 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 218 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 219 int neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
 220 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 221 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 222                                                 u8 *lladdr, void *saddr,
 223                                                 struct net_device *dev);
 224
 225 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 226                                       struct neigh_table *tbl);
 227 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 228
 229 static inline
 230 struct net *neigh_parms_net(const struct neigh_parms *parms)
 231 {
 232         return read_pnet(&parms->net);
 233 }
 234
 235 unsigned long neigh_rand_reach_time(unsigned long base);
 236
 237 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 238                     struct sk_buff *skb);
 239 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 240                                    const void *key, struct net_device *dev,
 241                                    int creat);
 242 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 243                                      const void *key, struct net_device *dev);
 244 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 245                   struct net_device *dev);
 246
 247 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 248 {
 249         return read_pnet(&pneigh->net);
 250 }
 251
 252 void neigh_app_ns(struct neighbour *n);
 253 void neigh_for_each(struct neigh_table *tbl,
 254                     void (*cb)(struct neighbour *, void *), void *cookie);
 255 void __neigh_for_each_release(struct neigh_table *tbl,
 256                               int (*cb)(struct neighbour *));
 257 void pneigh_for_each(struct neigh_table *tbl,
 258                      void (*cb)(struct pneigh_entry *));
 259
 260 struct neigh_seq_state {
 261         struct seq_net_private p;
 262         struct neigh_table *tbl;
 263         struct neigh_hash_table *nht;
 264         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 265                                 struct neighbour *n, loff_t *pos);
 266         unsigned int bucket;
 267         unsigned int flags;
 268 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 269 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 270 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 271 };
 272 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 273                       unsigned int);
 274 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 275 void neigh_seq_stop(struct seq_file *, void *);
 276
 277 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 278                           char *p_name, proc_handler *proc_handler);
 279 void neigh_sysctl_unregister(struct neigh_parms *p);
 280
 281 static inline void __neigh_parms_put(struct neigh_parms *parms)
 282 {
 283         atomic_dec(&parms->refcnt);
 284 }
 285
 286 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 287 {
 288         atomic_inc(&parms->refcnt);
 289         return parms;
 290 }
 291
 292 /*
 293  *      Neighbour references
 294  */
 295
 296 static inline void neigh_release(struct neighbour *neigh)
 297 {
 298         if (atomic_dec_and_test(&neigh->refcnt))
 299                 neigh_destroy(neigh);
 300 }
 301
 302 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 303 {
 304         if (neigh)
 305                 atomic_inc(&neigh->refcnt);
 306         return neigh;
 307 }
 308
 309 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 310
 311 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 312 {
 313         unsigned long now = jiffies;
 314
 315         if (neigh->used != now)
 316                 neigh->used = now;
 317         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 318                 return __neigh_event_send(neigh, skb);
 319         return 0;
 320 }
 321
 322 #ifdef CONFIG_BRIDGE_NETFILTER
 323 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 324 {
 325         unsigned int seq, hh_alen;
 326
 327         do {
 328                 seq = read_seqbegin(&hh->hh_lock);
 329                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 330                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 331         } while (read_seqretry(&hh->hh_lock, seq));
 332         return 0;
 333 }
 334 #endif
 335
 336 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 337 {
 338         unsigned int seq;
 339         int hh_len;
 340
 341         do {
 342                 seq = read_seqbegin(&hh->hh_lock);
 343                 hh_len = hh->hh_len;
 344                 if (likely(hh_len <= HH_DATA_MOD)) {
 345                         /* this is inlined by gcc */
 346                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
 347                 } else {
 348                         int hh_alen = HH_DATA_ALIGN(hh_len);
 349
 350                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 351                 }
 352         } while (read_seqretry(&hh->hh_lock, seq));
 353
 354         skb_push(skb, hh_len);
 355         return dev_queue_xmit(skb);
 356 }
 357
 358 static inline struct neighbour *
 359 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 360 {
 361         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 362
 363         if (n || !creat)
 364                 return n;
 365
 366         n = neigh_create(tbl, pkey, dev);
 367         return IS_ERR(n) ? NULL : n;
 368 }
 369
 370 static inline struct neighbour *
 371 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 372   struct net_device *dev)
 373 {
 374         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 375
 376         if (n)
 377                 return n;
 378
 379         return neigh_create(tbl, pkey, dev);
 380 }
 381
 382 struct neighbour_cb {
 383         unsigned long sched_next;
 384         unsigned int flags;
 385 };
 386
 387 #define LOCALLY_ENQUEUED 0x1
 388
 389 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 390
 391 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 392                                      const struct net_device *dev)
 393 {
 394         unsigned int seq;
 395
 396         do {
 397                 seq = read_seqbegin(&n->ha_lock);
 398                 memcpy(dst, n->ha, dev->addr_len);
 399         } while (read_seqretry(&n->ha_lock, seq));
 400 }
 401 #endif