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 struct neigh_hash_table {
 143         struct neighbour __rcu  **hash_buckets;
 144         unsigned int            hash_shift;
 145         __u32                   hash_rnd;
 146         struct rcu_head         rcu;
 147 };
 148
 149
 150 struct neigh_table {
 151         struct neigh_table      *next;
 152         int                     family;
 153         int                     entry_size;
 154         int                     key_len;
 155         __u32                   (*hash)(const void *pkey,
 156                                         const struct net_device *dev,
 157                                         __u32 hash_rnd);
 158         int                     (*constructor)(struct neighbour *);
 159         int                     (*pconstructor)(struct pneigh_entry *);
 160         void                    (*pdestructor)(struct pneigh_entry *);
 161         void                    (*proxy_redo)(struct sk_buff *skb);
 162         char                    *id;
 163         struct neigh_parms      parms;
 164         /* HACK. gc_* should follow parms without a gap! */
 165         int                     gc_interval;
 166         int                     gc_thresh1;
 167         int                     gc_thresh2;
 168         int                     gc_thresh3;
 169         unsigned long           last_flush;
 170         struct delayed_work     gc_work;
 171         struct timer_list       proxy_timer;
 172         struct sk_buff_head     proxy_queue;
 173         atomic_t                entries;
 174         rwlock_t                lock;
 175         unsigned long           last_rand;
 176         struct neigh_statistics __percpu *stats;
 177         struct neigh_hash_table __rcu *nht;
 178         struct pneigh_entry     **phash_buckets;
 179 };
 180
 181 #define NEIGH_PRIV_ALIGN        sizeof(long long)
 182
 183 static inline void *neighbour_priv(const struct neighbour *n)
 184 {
 185         return (char *)n + ALIGN(sizeof(*n) + n->tbl->key_len, NEIGH_PRIV_ALIGN);
 186 }
 187
 188 /* flags for neigh_update() */
 189 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 190 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 191 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 192 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 193 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
 194
 195 extern void                     neigh_table_init(struct neigh_table *tbl);
 196 extern void                     neigh_table_init_no_netlink(struct neigh_table *tbl);
 197 extern int                      neigh_table_clear(struct neigh_table *tbl);
 198 extern struct neighbour *       neigh_lookup(struct neigh_table *tbl,
 199                                              const void *pkey,
 200                                              struct net_device *dev);
 201 extern struct neighbour *       neigh_lookup_nodev(struct neigh_table *tbl,
 202                                                    struct net *net,
 203                                                    const void *pkey);
 204 extern struct neighbour *       neigh_create(struct neigh_table *tbl,
 205                                              const void *pkey,
 206                                              struct net_device *dev);
 207 extern void                     neigh_destroy(struct neighbour *neigh);
 208 extern int                      __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 209 extern int                      neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 210                                              u32 flags);
 211 extern void                     neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 212 extern int                      neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 213 extern int                      neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 214 extern int                      neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 215 extern int                      neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
 216 extern int                      neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 217 extern struct neighbour         *neigh_event_ns(struct neigh_table *tbl,
 218                                                 u8 *lladdr, void *saddr,
 219                                                 struct net_device *dev);
 220
 221 extern struct neigh_parms       *neigh_parms_alloc(struct net_device *dev, struct neigh_table *tbl);
 222 extern void                     neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 223
 224 static inline
 225 struct net                      *neigh_parms_net(const struct neigh_parms *parms)
 226 {
 227         return read_pnet(&parms->net);
 228 }
 229
 230 extern unsigned long            neigh_rand_reach_time(unsigned long base);
 231
 232 extern void                     pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 233                                                struct sk_buff *skb);
 234 extern struct pneigh_entry      *pneigh_lookup(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev, int creat);
 235 extern struct pneigh_entry      *__pneigh_lookup(struct neigh_table *tbl,
 236                                                  struct net *net,
 237                                                  const void *key,
 238                                                  struct net_device *dev);
 239 extern int                      pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev);
 240
 241 static inline
 242 struct net                      *pneigh_net(const struct pneigh_entry *pneigh)
 243 {
 244         return read_pnet(&pneigh->net);
 245 }
 246
 247 extern void neigh_app_ns(struct neighbour *n);
 248 extern void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie);
 249 extern void __neigh_for_each_release(struct neigh_table *tbl, int (*cb)(struct neighbour *));
 250 extern void pneigh_for_each(struct neigh_table *tbl, void (*cb)(struct pneigh_entry *));
 251
 252 struct neigh_seq_state {
 253         struct seq_net_private p;
 254         struct neigh_table *tbl;
 255         struct neigh_hash_table *nht;
 256         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 257                                 struct neighbour *n, loff_t *pos);
 258         unsigned int bucket;
 259         unsigned int flags;
 260 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 261 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 262 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 263 };
 264 extern void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, unsigned int);
 265 extern void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 266 extern void neigh_seq_stop(struct seq_file *, void *);
 267
 268 extern int                      neigh_sysctl_register(struct net_device *dev,
 269                                                       struct neigh_parms *p,
 270                                                       char *p_name,
 271                                                       proc_handler *proc_handler);
 272 extern void                     neigh_sysctl_unregister(struct neigh_parms *p);
 273
 274 static inline void __neigh_parms_put(struct neigh_parms *parms)
 275 {
 276         atomic_dec(&parms->refcnt);
 277 }
 278
 279 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 280 {
 281         atomic_inc(&parms->refcnt);
 282         return parms;
 283 }
 284
 285 /*
 286  *      Neighbour references
 287  */
 288
 289 static inline void neigh_release(struct neighbour *neigh)
 290 {
 291         if (atomic_dec_and_test(&neigh->refcnt))
 292                 neigh_destroy(neigh);
 293 }
 294
 295 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 296 {
 297         if (neigh)
 298                 atomic_inc(&neigh->refcnt);
 299         return neigh;
 300 }
 301
 302 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 303
 304 static inline void neigh_confirm(struct neighbour *neigh)
 305 {
 306         if (neigh)
 307                 neigh->confirmed = jiffies;
 308 }
 309
 310 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 311 {
 312         unsigned long now = jiffies;
 313
 314         if (neigh->used != now)
 315                 neigh->used = now;
 316         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 317                 return __neigh_event_send(neigh, skb);
 318         return 0;
 319 }
 320
 321 #ifdef CONFIG_BRIDGE_NETFILTER
 322 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 323 {
 324         unsigned seq, hh_alen;
 325
 326         do {
 327                 seq = read_seqbegin(&hh->hh_lock);
 328                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 329                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 330         } while (read_seqretry(&hh->hh_lock, seq));
 331         return 0;
 332 }
 333 #endif
 334
 335 static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
 336 {
 337         unsigned seq;
 338         int hh_len;
 339
 340         do {
 341                 int hh_alen;
 342
 343                 seq = read_seqbegin(&hh->hh_lock);
 344                 hh_len = hh->hh_len;
 345                 hh_alen = HH_DATA_ALIGN(hh_len);
 346                 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 347         } while (read_seqretry(&hh->hh_lock, seq));
 348
 349         skb_push(skb, hh_len);
 350         return dev_queue_xmit(skb);
 351 }
 352
 353 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb)
 354 {
 355         struct hh_cache *hh = &n->hh;
 356         if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
 357                 return neigh_hh_output(hh, skb);
 358         else
 359                 return n->output(n, skb);
 360 }
 361
 362 static inline struct neighbour *
 363 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 364 {
 365         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 366
 367         if (n || !creat)
 368                 return n;
 369
 370         n = neigh_create(tbl, pkey, dev);
 371         return IS_ERR(n) ? NULL : n;
 372 }
 373
 374 static inline struct neighbour *
 375 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 376   struct net_device *dev)
 377 {
 378         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 379
 380         if (n)
 381                 return n;
 382
 383         return neigh_create(tbl, pkey, dev);
 384 }
 385
 386 struct neighbour_cb {
 387         unsigned long sched_next;
 388         unsigned int flags;
 389 };
 390
 391 #define LOCALLY_ENQUEUED 0x1
 392
 393 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 394
 395 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 396                                      const struct net_device *dev)
 397 {
 398         unsigned int seq;
 399
 400         do {
 401                 seq = read_seqbegin(&n->ha_lock);
 402                 memcpy(dst, n->ha, dev->addr_len);
 403         } while (read_seqretry(&n->ha_lock, seq));
 404 }
 405 #endif