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 <asm/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;
  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         __u8                    flags;
 100         __u8                    nud_state;
 101         __u8                    type;
 102         __u8                    dead;
 103         atomic_t                refcnt;
 104         struct sk_buff_head     arp_queue;
 105         struct timer_list       timer;
 106         unsigned long           used;
 107         atomic_t                probes;
 108         rwlock_t                lock;
 109         seqlock_t               ha_lock;
 110         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
 111         struct hh_cache         *hh;
 112         int                     (*output)(struct sk_buff *skb);
 113         const struct neigh_ops  *ops;
 114         struct rcu_head         rcu;
 115         struct net_device       *dev;
 116         u8                      primary_key[0];
 117 };
 118
 119 struct neigh_ops {
 120         int                     family;
 121         void                    (*solicit)(struct neighbour *, struct sk_buff*);
 122         void                    (*error_report)(struct neighbour *, struct sk_buff*);
 123         int                     (*output)(struct sk_buff*);
 124         int                     (*connected_output)(struct sk_buff*);
 125         int                     (*hh_output)(struct sk_buff*);
 126         int                     (*queue_xmit)(struct sk_buff*);
 127 };
 128
 129 struct pneigh_entry {
 130         struct pneigh_entry     *next;
 131 #ifdef CONFIG_NET_NS
 132         struct net              *net;
 133 #endif
 134         struct net_device       *dev;
 135         u8                      flags;
 136         u8                      key[0];
 137 };
 138
 139 /*
 140  *      neighbour table manipulation
 141  */
 142
 143 struct neigh_hash_table {
 144         struct neighbour __rcu  **hash_buckets;
 145         unsigned int            hash_mask;
 146         __u32                   hash_rnd;
 147         struct rcu_head         rcu;
 148 };
 149
 150
 151 struct neigh_table {
 152         struct neigh_table      *next;
 153         int                     family;
 154         int                     entry_size;
 155         int                     key_len;
 156         __u32                   (*hash)(const void *pkey,
 157                                         const struct net_device *dev,
 158                                         __u32 hash_rnd);
 159         int                     (*constructor)(struct neighbour *);
 160         int                     (*pconstructor)(struct pneigh_entry *);
 161         void                    (*pdestructor)(struct pneigh_entry *);
 162         void                    (*proxy_redo)(struct sk_buff *skb);
 163         char                    *id;
 164         struct neigh_parms      parms;
 165         /* HACK. gc_* should follow parms without a gap! */
 166         int                     gc_interval;
 167         int                     gc_thresh1;
 168         int                     gc_thresh2;
 169         int                     gc_thresh3;
 170         unsigned long           last_flush;
 171         struct delayed_work     gc_work;
 172         struct timer_list       proxy_timer;
 173         struct sk_buff_head     proxy_queue;
 174         atomic_t                entries;
 175         rwlock_t                lock;
 176         unsigned long           last_rand;
 177         struct kmem_cache       *kmem_cachep;
 178         struct neigh_statistics __percpu *stats;
 179         struct neigh_hash_table __rcu *nht;
 180         struct pneigh_entry     **phash_buckets;
 181 };
 182
 183 /* flags for neigh_update() */
 184 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 185 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 186 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 187 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 188 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
 189
 190 extern void                     neigh_table_init(struct neigh_table *tbl);
 191 extern void                     neigh_table_init_no_netlink(struct neigh_table *tbl);
 192 extern int                      neigh_table_clear(struct neigh_table *tbl);
 193 extern struct neighbour *       neigh_lookup(struct neigh_table *tbl,
 194                                              const void *pkey,
 195                                              struct net_device *dev);
 196 extern struct neighbour *       neigh_lookup_nodev(struct neigh_table *tbl,
 197                                                    struct net *net,
 198                                                    const void *pkey);
 199 extern struct neighbour *       neigh_create(struct neigh_table *tbl,
 200                                              const void *pkey,
 201                                              struct net_device *dev);
 202 extern void                     neigh_destroy(struct neighbour *neigh);
 203 extern int                      __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 204 extern int                      neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 205                                              u32 flags);
 206 extern void                     neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 207 extern int                      neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 208 extern int                      neigh_resolve_output(struct sk_buff *skb);
 209 extern int                      neigh_connected_output(struct sk_buff *skb);
 210 extern int                      neigh_compat_output(struct sk_buff *skb);
 211 extern struct neighbour         *neigh_event_ns(struct neigh_table *tbl,
 212                                                 u8 *lladdr, void *saddr,
 213                                                 struct net_device *dev);
 214
 215 extern struct neigh_parms       *neigh_parms_alloc(struct net_device *dev, struct neigh_table *tbl);
 216 extern void                     neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 217
 218 static inline
 219 struct net                      *neigh_parms_net(const struct neigh_parms *parms)
 220 {
 221         return read_pnet(&parms->net);
 222 }
 223
 224 extern unsigned long            neigh_rand_reach_time(unsigned long base);
 225
 226 extern void                     pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 227                                                struct sk_buff *skb);
 228 extern struct pneigh_entry      *pneigh_lookup(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev, int creat);
 229 extern struct pneigh_entry      *__pneigh_lookup(struct neigh_table *tbl,
 230                                                  struct net *net,
 231                                                  const void *key,
 232                                                  struct net_device *dev);
 233 extern int                      pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev);
 234
 235 static inline
 236 struct net                      *pneigh_net(const struct pneigh_entry *pneigh)
 237 {
 238         return read_pnet(&pneigh->net);
 239 }
 240
 241 extern void neigh_app_ns(struct neighbour *n);
 242 extern void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie);
 243 extern void __neigh_for_each_release(struct neigh_table *tbl, int (*cb)(struct neighbour *));
 244 extern void pneigh_for_each(struct neigh_table *tbl, void (*cb)(struct pneigh_entry *));
 245
 246 struct neigh_seq_state {
 247         struct seq_net_private p;
 248         struct neigh_table *tbl;
 249         struct neigh_hash_table *nht;
 250         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 251                                 struct neighbour *n, loff_t *pos);
 252         unsigned int bucket;
 253         unsigned int flags;
 254 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 255 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
 256 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
 257 };
 258 extern void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, unsigned int);
 259 extern void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 260 extern void neigh_seq_stop(struct seq_file *, void *);
 261
 262 extern int                      neigh_sysctl_register(struct net_device *dev,
 263                                                       struct neigh_parms *p,
 264                                                       char *p_name,
 265                                                       proc_handler *proc_handler);
 266 extern void                     neigh_sysctl_unregister(struct neigh_parms *p);
 267
 268 static inline void __neigh_parms_put(struct neigh_parms *parms)
 269 {
 270         atomic_dec(&parms->refcnt);
 271 }
 272
 273 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 274 {
 275         atomic_inc(&parms->refcnt);
 276         return parms;
 277 }
 278
 279 /*
 280  *      Neighbour references
 281  */
 282
 283 static inline void neigh_release(struct neighbour *neigh)
 284 {
 285         if (atomic_dec_and_test(&neigh->refcnt))
 286                 neigh_destroy(neigh);
 287 }
 288
 289 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 290 {
 291         if (neigh)
 292                 atomic_inc(&neigh->refcnt);
 293         return neigh;
 294 }
 295
 296 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 297
 298 static inline void neigh_confirm(struct neighbour *neigh)
 299 {
 300         if (neigh)
 301                 neigh->confirmed = jiffies;
 302 }
 303
 304 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 305 {
 306         unsigned long now = ACCESS_ONCE(jiffies);
 307
 308         if (neigh->used != now)
 309                 neigh->used = now;
 310         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 311                 return __neigh_event_send(neigh, skb);
 312         return 0;
 313 }
 314
 315 #ifdef CONFIG_BRIDGE_NETFILTER
 316 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 317 {
 318         unsigned seq, hh_alen;
 319
 320         do {
 321                 seq = read_seqbegin(&hh->hh_lock);
 322                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 323                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 324         } while (read_seqretry(&hh->hh_lock, seq));
 325         return 0;
 326 }
 327 #endif
 328
 329 static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
 330 {
 331         unsigned seq;
 332         int hh_len;
 333
 334         do {
 335                 int hh_alen;
 336
 337                 seq = read_seqbegin(&hh->hh_lock);
 338                 hh_len = hh->hh_len;
 339                 hh_alen = HH_DATA_ALIGN(hh_len);
 340                 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 341         } while (read_seqretry(&hh->hh_lock, seq));
 342
 343         skb_push(skb, hh_len);
 344         return hh->hh_output(skb);
 345 }
 346
 347 static inline struct neighbour *
 348 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 349 {
 350         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 351
 352         if (n || !creat)
 353                 return n;
 354
 355         n = neigh_create(tbl, pkey, dev);
 356         return IS_ERR(n) ? NULL : n;
 357 }
 358
 359 static inline struct neighbour *
 360 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 361   struct net_device *dev)
 362 {
 363         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 364
 365         if (n)
 366                 return n;
 367
 368         return neigh_create(tbl, pkey, dev);
 369 }
 370
 371 struct neighbour_cb {
 372         unsigned long sched_next;
 373         unsigned int flags;
 374 };
 375
 376 #define LOCALLY_ENQUEUED 0x1
 377
 378 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 379
 380 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 381                                      const struct net_device *dev)
 382 {
 383         unsigned int seq;
 384
 385         do {
 386                 seq = read_seqbegin(&n->ha_lock);
 387                 memcpy(dst, n->ha, dev->addr_len);
 388         } while (read_seqretry(&n->ha_lock, seq));
 389 }
 390 #endif