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 extern void                     neigh_table_init(struct neigh_table *tbl);
 199 extern int                      neigh_table_clear(struct neigh_table *tbl);
 200 extern struct neighbour *       neigh_lookup(struct neigh_table *tbl,
 201                                              const void *pkey,
 202                                              struct net_device *dev);
 203 extern struct neighbour *       neigh_lookup_nodev(struct neigh_table *tbl,
 204                                                    struct net *net,
 205                                                    const void *pkey);
 206 extern struct neighbour *       __neigh_create(struct neigh_table *tbl,
 207                                                const void *pkey,
 208                                                struct net_device *dev,
 209                                                bool want_ref);
 210 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 211                                              const void *pkey,
 212                                              struct net_device *dev)
 213 {
 214         return __neigh_create(tbl, pkey, dev, true);
 215 }
 216 extern void                     neigh_destroy(struct neighbour *neigh);
 217 extern int                      __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 218 extern int                      neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 219                                              u32 flags);
 220 extern void                     neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 221 extern int                      neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 222 extern int                      neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 223 extern int                      neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 224 extern int                      neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
 225 extern int                      neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 226 extern struct neighbour         *neigh_event_ns(struct neigh_table *tbl,
 227                                                 u8 *lladdr, void *saddr,
 228                                                 struct net_device *dev);
 229
 230 extern struct neigh_parms       *neigh_parms_alloc(struct net_device *dev, struct neigh_table *tbl);
 231 extern void                     neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 232
 233 static inline
 234 struct net                      *neigh_parms_net(const struct neigh_parms *parms)
 235 {
 236         return read_pnet(&parms->net);
 237 }
 238
 239 extern unsigned long            neigh_rand_reach_time(unsigned long base);
 240
 241 extern void                     pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 242                                                struct sk_buff *skb);
 243 extern struct pneigh_entry      *pneigh_lookup(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev, int creat);
 244 extern struct pneigh_entry      *__pneigh_lookup(struct neigh_table *tbl,
 245                                                  struct net *net,
 246                                                  const void *key,
 247                                                  struct net_device *dev);
 248 extern int                      pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev);
 249
 250 static inline
 251 struct net                      *pneigh_net(const struct pneigh_entry *pneigh)
 252 {
 253         return read_pnet(&pneigh->net);
 254 }
 255
 256 extern void neigh_app_ns(struct neighbour *n);
 257 extern void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie);
 258 extern void __neigh_for_each_release(struct neigh_table *tbl, int (*cb)(struct neighbour *));
 259 extern void pneigh_for_each(struct neigh_table *tbl, void (*cb)(struct pneigh_entry *));
 260
 261 struct neigh_seq_state {
 262         struct seq_net_private p;
 263         struct neigh_table *tbl;
 264         struct neigh_hash_table *nht;
 265         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 266                                 struct neighbour *n, loff_t *pos);
 267         unsigned int bucket;
 268         unsigned int flags;
 269 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 270 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 271 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 272 };
 273 extern void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, unsigned int);
 274 extern void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 275 extern void neigh_seq_stop(struct seq_file *, void *);
 276
 277 extern int                      neigh_sysctl_register(struct net_device *dev,
 278                                                       struct neigh_parms *p,
 279                                                       char *p_name,
 280                                                       proc_handler *proc_handler);
 281 extern void                     neigh_sysctl_unregister(struct neigh_parms *p);
 282
 283 static inline void __neigh_parms_put(struct neigh_parms *parms)
 284 {
 285         atomic_dec(&parms->refcnt);
 286 }
 287
 288 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 289 {
 290         atomic_inc(&parms->refcnt);
 291         return parms;
 292 }
 293
 294 /*
 295  *      Neighbour references
 296  */
 297
 298 static inline void neigh_release(struct neighbour *neigh)
 299 {
 300         if (atomic_dec_and_test(&neigh->refcnt))
 301                 neigh_destroy(neigh);
 302 }
 303
 304 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 305 {
 306         if (neigh)
 307                 atomic_inc(&neigh->refcnt);
 308         return neigh;
 309 }
 310
 311 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 312
 313 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 314 {
 315         unsigned long now = jiffies;
 316
 317         if (neigh->used != now)
 318                 neigh->used = now;
 319         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 320                 return __neigh_event_send(neigh, skb);
 321         return 0;
 322 }
 323
 324 #ifdef CONFIG_BRIDGE_NETFILTER
 325 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 326 {
 327         unsigned int seq, hh_alen;
 328
 329         do {
 330                 seq = read_seqbegin(&hh->hh_lock);
 331                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 332                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 333         } while (read_seqretry(&hh->hh_lock, seq));
 334         return 0;
 335 }
 336 #endif
 337
 338 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 339 {
 340         unsigned int seq;
 341         int hh_len;
 342
 343         do {
 344                 seq = read_seqbegin(&hh->hh_lock);
 345                 hh_len = hh->hh_len;
 346                 if (likely(hh_len <= HH_DATA_MOD)) {
 347                         /* this is inlined by gcc */
 348                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
 349                 } else {
 350                         int hh_alen = HH_DATA_ALIGN(hh_len);
 351
 352                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 353                 }
 354         } while (read_seqretry(&hh->hh_lock, seq));
 355
 356         skb_push(skb, hh_len);
 357         return dev_queue_xmit(skb);
 358 }
 359
 360 static inline struct neighbour *
 361 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 362 {
 363         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 364
 365         if (n || !creat)
 366                 return n;
 367
 368         n = neigh_create(tbl, pkey, dev);
 369         return IS_ERR(n) ? NULL : n;
 370 }
 371
 372 static inline struct neighbour *
 373 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 374   struct net_device *dev)
 375 {
 376         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 377
 378         if (n)
 379                 return n;
 380
 381         return neigh_create(tbl, pkey, dev);
 382 }
 383
 384 struct neighbour_cb {
 385         unsigned long sched_next;
 386         unsigned int flags;
 387 };
 388
 389 #define LOCALLY_ENQUEUED 0x1
 390
 391 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 392
 393 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 394                                      const struct net_device *dev)
 395 {
 396         unsigned int seq;
 397
 398         do {
 399                 seq = read_seqbegin(&n->ha_lock);
 400                 memcpy(dst, n->ha, dev->addr_len);
 401         } while (read_seqretry(&n->ha_lock, seq));
 402 }
 403 #endif