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 #include <linux/bitmap.h>
  25
  26 #include <linux/err.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/workqueue.h>
  29 #include <net/rtnetlink.h>
  30
  31 /*
  32  * NUD stands for "neighbor unreachability detection"
  33  */
  34
  35 #define NUD_IN_TIMER    (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
  36 #define NUD_VALID       (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
  37 #define NUD_CONNECTED   (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
  38
  39 struct neighbour;
  40
  41 enum {
  42         NEIGH_VAR_MCAST_PROBES,
  43         NEIGH_VAR_UCAST_PROBES,
  44         NEIGH_VAR_APP_PROBES,
  45         NEIGH_VAR_RETRANS_TIME,
  46         NEIGH_VAR_BASE_REACHABLE_TIME,
  47         NEIGH_VAR_DELAY_PROBE_TIME,
  48         NEIGH_VAR_GC_STALETIME,
  49         NEIGH_VAR_QUEUE_LEN_BYTES,
  50         NEIGH_VAR_PROXY_QLEN,
  51         NEIGH_VAR_ANYCAST_DELAY,
  52         NEIGH_VAR_PROXY_DELAY,
  53         NEIGH_VAR_LOCKTIME,
  54 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
  55         /* Following are used as a second way to access one of the above */
  56         NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
  57         NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
  58         NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
  59         /* Following are used by "default" only */
  60         NEIGH_VAR_GC_INTERVAL,
  61         NEIGH_VAR_GC_THRESH1,
  62         NEIGH_VAR_GC_THRESH2,
  63         NEIGH_VAR_GC_THRESH3,
  64         NEIGH_VAR_MAX
  65 };
  66
  67 struct neigh_parms {
  68 #ifdef CONFIG_NET_NS
  69         struct net *net;
  70 #endif
  71         struct net_device *dev;
  72         struct neigh_parms *next;
  73         int     (*neigh_setup)(struct neighbour *);
  74         void    (*neigh_cleanup)(struct neighbour *);
  75         struct neigh_table *tbl;
  76
  77         void    *sysctl_table;
  78
  79         int dead;
  80         atomic_t refcnt;
  81         struct rcu_head rcu_head;
  82
  83         int     reachable_time;
  84         int     data[NEIGH_VAR_DATA_MAX];
  85         DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
  86 };
  87
  88 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
  89 {
  90         set_bit(index, p->data_state);
  91         p->data[index] = val;
  92 }
  93
  94 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
  95 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
  96
  97 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
  98 {
  99         bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
 100 }
 101
 102 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
 103 {
 104         bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
 105 }
 106
 107 struct neigh_statistics {
 108         unsigned long allocs;           /* number of allocated neighs */
 109         unsigned long destroys;         /* number of destroyed neighs */
 110         unsigned long hash_grows;       /* number of hash resizes */
 111
 112         unsigned long res_failed;       /* number of failed resolutions */
 113
 114         unsigned long lookups;          /* number of lookups */
 115         unsigned long hits;             /* number of hits (among lookups) */
 116
 117         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
 118         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
 119
 120         unsigned long periodic_gc_runs; /* number of periodic GC runs */
 121         unsigned long forced_gc_runs;   /* number of forced GC runs */
 122
 123         unsigned long unres_discards;   /* number of unresolved drops */
 124 };
 125
 126 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
 127
 128 struct neighbour {
 129         struct neighbour __rcu  *next;
 130         struct neigh_table      *tbl;
 131         struct neigh_parms      *parms;
 132         unsigned long           confirmed;
 133         unsigned long           updated;
 134         rwlock_t                lock;
 135         atomic_t                refcnt;
 136         struct sk_buff_head     arp_queue;
 137         unsigned int            arp_queue_len_bytes;
 138         struct timer_list       timer;
 139         unsigned long           used;
 140         atomic_t                probes;
 141         __u8                    flags;
 142         __u8                    nud_state;
 143         __u8                    type;
 144         __u8                    dead;
 145         seqlock_t               ha_lock;
 146         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
 147         struct hh_cache         hh;
 148         int                     (*output)(struct neighbour *, struct sk_buff *);
 149         const struct neigh_ops  *ops;
 150         struct rcu_head         rcu;
 151         struct net_device       *dev;
 152         u8                      primary_key[0];
 153 };
 154
 155 struct neigh_ops {
 156         int                     family;
 157         void                    (*solicit)(struct neighbour *, struct sk_buff *);
 158         void                    (*error_report)(struct neighbour *, struct sk_buff *);
 159         int                     (*output)(struct neighbour *, struct sk_buff *);
 160         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
 161 };
 162
 163 struct pneigh_entry {
 164         struct pneigh_entry     *next;
 165 #ifdef CONFIG_NET_NS
 166         struct net              *net;
 167 #endif
 168         struct net_device       *dev;
 169         u8                      flags;
 170         u8                      key[0];
 171 };
 172
 173 /*
 174  *      neighbour table manipulation
 175  */
 176
 177 #define NEIGH_NUM_HASH_RND      4
 178
 179 struct neigh_hash_table {
 180         struct neighbour __rcu  **hash_buckets;
 181         unsigned int            hash_shift;
 182         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
 183         struct rcu_head         rcu;
 184 };
 185
 186
 187 struct neigh_table {
 188         struct neigh_table      *next;
 189         int                     family;
 190         int                     entry_size;
 191         int                     key_len;
 192         __u32                   (*hash)(const void *pkey,
 193                                         const struct net_device *dev,
 194                                         __u32 *hash_rnd);
 195         int                     (*constructor)(struct neighbour *);
 196         int                     (*pconstructor)(struct pneigh_entry *);
 197         void                    (*pdestructor)(struct pneigh_entry *);
 198         void                    (*proxy_redo)(struct sk_buff *skb);
 199         char                    *id;
 200         struct neigh_parms      parms;
 201         /* HACK. gc_* should follow parms without a gap! */
 202         int                     gc_interval;
 203         int                     gc_thresh1;
 204         int                     gc_thresh2;
 205         int                     gc_thresh3;
 206         unsigned long           last_flush;
 207         struct delayed_work     gc_work;
 208         struct timer_list       proxy_timer;
 209         struct sk_buff_head     proxy_queue;
 210         atomic_t                entries;
 211         rwlock_t                lock;
 212         unsigned long           last_rand;
 213         struct neigh_statistics __percpu *stats;
 214         struct neigh_hash_table __rcu *nht;
 215         struct pneigh_entry     **phash_buckets;
 216 };
 217
 218 static inline int neigh_parms_family(struct neigh_parms *p)
 219 {
 220         return p->tbl->family;
 221 }
 222
 223 #define NEIGH_PRIV_ALIGN        sizeof(long long)
 224 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
 225
 226 static inline void *neighbour_priv(const struct neighbour *n)
 227 {
 228         return (char *)n + n->tbl->entry_size;
 229 }
 230
 231 /* flags for neigh_update() */
 232 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 233 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 234 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 235 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 236 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
 237
 238 void neigh_table_init(struct neigh_table *tbl);
 239 int neigh_table_clear(struct neigh_table *tbl);
 240 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 241                                struct net_device *dev);
 242 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
 243                                      const void *pkey);
 244 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 245                                  struct net_device *dev, bool want_ref);
 246 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 247                                              const void *pkey,
 248                                              struct net_device *dev)
 249 {
 250         return __neigh_create(tbl, pkey, dev, true);
 251 }
 252 void neigh_destroy(struct neighbour *neigh);
 253 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 254 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
 255 void __neigh_set_probe_once(struct neighbour *neigh);
 256 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 257 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 258 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 259 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 260 int neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
 261 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 262 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 263                                                 u8 *lladdr, void *saddr,
 264                                                 struct net_device *dev);
 265
 266 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 267                                       struct neigh_table *tbl);
 268 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 269
 270 static inline
 271 struct net *neigh_parms_net(const struct neigh_parms *parms)
 272 {
 273         return read_pnet(&parms->net);
 274 }
 275
 276 unsigned long neigh_rand_reach_time(unsigned long base);
 277
 278 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 279                     struct sk_buff *skb);
 280 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
 281                                    const void *key, struct net_device *dev,
 282                                    int creat);
 283 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
 284                                      const void *key, struct net_device *dev);
 285 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
 286                   struct net_device *dev);
 287
 288 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 289 {
 290         return read_pnet(&pneigh->net);
 291 }
 292
 293 void neigh_app_ns(struct neighbour *n);
 294 void neigh_for_each(struct neigh_table *tbl,
 295                     void (*cb)(struct neighbour *, void *), void *cookie);
 296 void __neigh_for_each_release(struct neigh_table *tbl,
 297                               int (*cb)(struct neighbour *));
 298 void pneigh_for_each(struct neigh_table *tbl,
 299                      void (*cb)(struct pneigh_entry *));
 300
 301 struct neigh_seq_state {
 302         struct seq_net_private p;
 303         struct neigh_table *tbl;
 304         struct neigh_hash_table *nht;
 305         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 306                                 struct neighbour *n, loff_t *pos);
 307         unsigned int bucket;
 308         unsigned int flags;
 309 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 310 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 311 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 312 };
 313 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 314                       unsigned int);
 315 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 316 void neigh_seq_stop(struct seq_file *, void *);
 317
 318 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
 319                         void __user *buffer, size_t *lenp, loff_t *ppos);
 320 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
 321                                 void __user *buffer,
 322                                 size_t *lenp, loff_t *ppos);
 323 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 324                                    void __user *buffer,
 325                                    size_t *lenp, loff_t *ppos);
 326
 327 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 328                           proc_handler *proc_handler);
 329 void neigh_sysctl_unregister(struct neigh_parms *p);
 330
 331 static inline void __neigh_parms_put(struct neigh_parms *parms)
 332 {
 333         atomic_dec(&parms->refcnt);
 334 }
 335
 336 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 337 {
 338         atomic_inc(&parms->refcnt);
 339         return parms;
 340 }
 341
 342 /*
 343  *      Neighbour references
 344  */
 345
 346 static inline void neigh_release(struct neighbour *neigh)
 347 {
 348         if (atomic_dec_and_test(&neigh->refcnt))
 349                 neigh_destroy(neigh);
 350 }
 351
 352 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 353 {
 354         if (neigh)
 355                 atomic_inc(&neigh->refcnt);
 356         return neigh;
 357 }
 358
 359 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 360
 361 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 362 {
 363         unsigned long now = jiffies;
 364
 365         if (neigh->used != now)
 366                 neigh->used = now;
 367         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 368                 return __neigh_event_send(neigh, skb);
 369         return 0;
 370 }
 371
 372 #ifdef CONFIG_BRIDGE_NETFILTER
 373 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 374 {
 375         unsigned int seq, hh_alen;
 376
 377         do {
 378                 seq = read_seqbegin(&hh->hh_lock);
 379                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 380                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 381         } while (read_seqretry(&hh->hh_lock, seq));
 382         return 0;
 383 }
 384 #endif
 385
 386 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
 387 {
 388         unsigned int seq;
 389         int hh_len;
 390
 391         do {
 392                 seq = read_seqbegin(&hh->hh_lock);
 393                 hh_len = hh->hh_len;
 394                 if (likely(hh_len <= HH_DATA_MOD)) {
 395                         /* this is inlined by gcc */
 396                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
 397                 } else {
 398                         int hh_alen = HH_DATA_ALIGN(hh_len);
 399
 400                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 401                 }
 402         } while (read_seqretry(&hh->hh_lock, seq));
 403
 404         skb_push(skb, hh_len);
 405         return dev_queue_xmit(skb);
 406 }
 407
 408 static inline struct neighbour *
 409 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 410 {
 411         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 412
 413         if (n || !creat)
 414                 return n;
 415
 416         n = neigh_create(tbl, pkey, dev);
 417         return IS_ERR(n) ? NULL : n;
 418 }
 419
 420 static inline struct neighbour *
 421 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 422   struct net_device *dev)
 423 {
 424         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 425
 426         if (n)
 427                 return n;
 428
 429         return neigh_create(tbl, pkey, dev);
 430 }
 431
 432 struct neighbour_cb {
 433         unsigned long sched_next;
 434         unsigned int flags;
 435 };
 436
 437 #define LOCALLY_ENQUEUED 0x1
 438
 439 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 440
 441 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 442                                      const struct net_device *dev)
 443 {
 444         unsigned int seq;
 445
 446         do {
 447                 seq = read_seqbegin(&n->ha_lock);
 448                 memcpy(dst, n->ha, dev->addr_len);
 449         } while (read_seqretry(&n->ha_lock, seq));
 450 }
 451 #endif