linux/include/net/neighbour.h
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   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
  38struct neighbour;
  39
  40struct 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
  72struct 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
  93struct 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        struct timer_list       timer;
 103        unsigned long           used;
 104        atomic_t                probes;
 105        __u8                    flags;
 106        __u8                    nud_state;
 107        __u8                    type;
 108        __u8                    dead;
 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 neighbour *, struct sk_buff *);
 113        const struct neigh_ops  *ops;
 114        struct rcu_head         rcu;
 115        struct net_device       *dev;
 116        u8                      primary_key[0];
 117};
 118
 119struct 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 neighbour *, struct sk_buff *);
 124        int                     (*connected_output)(struct neighbour *, struct sk_buff *);
 125};
 126
 127struct pneigh_entry {
 128        struct pneigh_entry     *next;
 129#ifdef CONFIG_NET_NS
 130        struct net              *net;
 131#endif
 132        struct net_device       *dev;
 133        u8                      flags;
 134        u8                      key[0];
 135};
 136
 137/*
 138 *      neighbour table manipulation
 139 */
 140
 141struct neigh_hash_table {
 142        struct neighbour __rcu  **hash_buckets;
 143        unsigned int            hash_shift;
 144        __u32                   hash_rnd;
 145        struct rcu_head         rcu;
 146};
 147
 148
 149struct neigh_table {
 150        struct neigh_table      *next;
 151        int                     family;
 152        int                     entry_size;
 153        int                     key_len;
 154        __u32                   (*hash)(const void *pkey,
 155                                        const struct net_device *dev,
 156                                        __u32 hash_rnd);
 157        int                     (*constructor)(struct neighbour *);
 158        int                     (*pconstructor)(struct pneigh_entry *);
 159        void                    (*pdestructor)(struct pneigh_entry *);
 160        void                    (*proxy_redo)(struct sk_buff *skb);
 161        char                    *id;
 162        struct neigh_parms      parms;
 163        /* HACK. gc_* should follow parms without a gap! */
 164        int                     gc_interval;
 165        int                     gc_thresh1;
 166        int                     gc_thresh2;
 167        int                     gc_thresh3;
 168        unsigned long           last_flush;
 169        struct delayed_work     gc_work;
 170        struct timer_list       proxy_timer;
 171        struct sk_buff_head     proxy_queue;
 172        atomic_t                entries;
 173        rwlock_t                lock;
 174        unsigned long           last_rand;
 175        struct kmem_cache       *kmem_cachep;
 176        struct neigh_statistics __percpu *stats;
 177        struct neigh_hash_table __rcu *nht;
 178        struct pneigh_entry     **phash_buckets;
 179};
 180
 181/* flags for neigh_update() */
 182#define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
 183#define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
 184#define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
 185#define NEIGH_UPDATE_F_ISROUTER                 0x40000000
 186#define NEIGH_UPDATE_F_ADMIN                    0x80000000
 187
 188extern void                     neigh_table_init(struct neigh_table *tbl);
 189extern void                     neigh_table_init_no_netlink(struct neigh_table *tbl);
 190extern int                      neigh_table_clear(struct neigh_table *tbl);
 191extern struct neighbour *       neigh_lookup(struct neigh_table *tbl,
 192                                             const void *pkey,
 193                                             struct net_device *dev);
 194extern struct neighbour *       neigh_lookup_nodev(struct neigh_table *tbl,
 195                                                   struct net *net,
 196                                                   const void *pkey);
 197extern struct neighbour *       neigh_create(struct neigh_table *tbl,
 198                                             const void *pkey,
 199                                             struct net_device *dev);
 200extern void                     neigh_destroy(struct neighbour *neigh);
 201extern int                      __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 202extern int                      neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, 
 203                                             u32 flags);
 204extern void                     neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 205extern int                      neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 206extern int                      neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
 207extern int                      neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
 208extern int                      neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
 209extern int                      neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
 210extern struct neighbour         *neigh_event_ns(struct neigh_table *tbl,
 211                                                u8 *lladdr, void *saddr,
 212                                                struct net_device *dev);
 213
 214extern struct neigh_parms       *neigh_parms_alloc(struct net_device *dev, struct neigh_table *tbl);
 215extern void                     neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 216
 217static inline
 218struct net                      *neigh_parms_net(const struct neigh_parms *parms)
 219{
 220        return read_pnet(&parms->net);
 221}
 222
 223extern unsigned long            neigh_rand_reach_time(unsigned long base);
 224
 225extern void                     pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 226                                               struct sk_buff *skb);
 227extern struct pneigh_entry      *pneigh_lookup(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev, int creat);
 228extern struct pneigh_entry      *__pneigh_lookup(struct neigh_table *tbl,
 229                                                 struct net *net,
 230                                                 const void *key,
 231                                                 struct net_device *dev);
 232extern int                      pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev);
 233
 234static inline
 235struct net                      *pneigh_net(const struct pneigh_entry *pneigh)
 236{
 237        return read_pnet(&pneigh->net);
 238}
 239
 240extern void neigh_app_ns(struct neighbour *n);
 241extern void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie);
 242extern void __neigh_for_each_release(struct neigh_table *tbl, int (*cb)(struct neighbour *));
 243extern void pneigh_for_each(struct neigh_table *tbl, void (*cb)(struct pneigh_entry *));
 244
 245struct neigh_seq_state {
 246        struct seq_net_private p;
 247        struct neigh_table *tbl;
 248        struct neigh_hash_table *nht;
 249        void *(*neigh_sub_iter)(struct neigh_seq_state *state,
 250                                struct neighbour *n, loff_t *pos);
 251        unsigned int bucket;
 252        unsigned int flags;
 253#define NEIGH_SEQ_NEIGH_ONLY    0x00000001
 254#define NEIGH_SEQ_IS_PNEIGH     0x00000002
 255#define NEIGH_SEQ_SKIP_NOARP    0x00000004
 256};
 257extern void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, unsigned int);
 258extern void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 259extern void neigh_seq_stop(struct seq_file *, void *);
 260
 261extern int                      neigh_sysctl_register(struct net_device *dev, 
 262                                                      struct neigh_parms *p,
 263                                                      char *p_name,
 264                                                      proc_handler *proc_handler);
 265extern void                     neigh_sysctl_unregister(struct neigh_parms *p);
 266
 267static inline void __neigh_parms_put(struct neigh_parms *parms)
 268{
 269        atomic_dec(&parms->refcnt);
 270}
 271
 272static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
 273{
 274        atomic_inc(&parms->refcnt);
 275        return parms;
 276}
 277
 278/*
 279 *      Neighbour references
 280 */
 281
 282static inline void neigh_release(struct neighbour *neigh)
 283{
 284        if (atomic_dec_and_test(&neigh->refcnt))
 285                neigh_destroy(neigh);
 286}
 287
 288static inline struct neighbour * neigh_clone(struct neighbour *neigh)
 289{
 290        if (neigh)
 291                atomic_inc(&neigh->refcnt);
 292        return neigh;
 293}
 294
 295#define neigh_hold(n)   atomic_inc(&(n)->refcnt)
 296
 297static inline void neigh_confirm(struct neighbour *neigh)
 298{
 299        if (neigh)
 300                neigh->confirmed = jiffies;
 301}
 302
 303static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 304{
 305        unsigned long now = jiffies;
 306        
 307        if (neigh->used != now)
 308                neigh->used = now;
 309        if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
 310                return __neigh_event_send(neigh, skb);
 311        return 0;
 312}
 313
 314#ifdef CONFIG_BRIDGE_NETFILTER
 315static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
 316{
 317        unsigned seq, hh_alen;
 318
 319        do {
 320                seq = read_seqbegin(&hh->hh_lock);
 321                hh_alen = HH_DATA_ALIGN(ETH_HLEN);
 322                memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
 323        } while (read_seqretry(&hh->hh_lock, seq));
 324        return 0;
 325}
 326#endif
 327
 328static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
 329{
 330        unsigned seq;
 331        int hh_len;
 332
 333        do {
 334                int hh_alen;
 335
 336                seq = read_seqbegin(&hh->hh_lock);
 337                hh_len = hh->hh_len;
 338                hh_alen = HH_DATA_ALIGN(hh_len);
 339                memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 340        } while (read_seqretry(&hh->hh_lock, seq));
 341
 342        skb_push(skb, hh_len);
 343        return dev_queue_xmit(skb);
 344}
 345
 346static inline int neigh_output(struct neighbour *n, struct sk_buff *skb)
 347{
 348        struct hh_cache *hh = &n->hh;
 349        if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
 350                return neigh_hh_output(hh, skb);
 351        else
 352                return n->output(n, skb);
 353}
 354
 355static inline struct neighbour *
 356__neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
 357{
 358        struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 359
 360        if (n || !creat)
 361                return n;
 362
 363        n = neigh_create(tbl, pkey, dev);
 364        return IS_ERR(n) ? NULL : n;
 365}
 366
 367static inline struct neighbour *
 368__neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
 369  struct net_device *dev)
 370{
 371        struct neighbour *n = neigh_lookup(tbl, pkey, dev);
 372
 373        if (n)
 374                return n;
 375
 376        return neigh_create(tbl, pkey, dev);
 377}
 378
 379struct neighbour_cb {
 380        unsigned long sched_next;
 381        unsigned int flags;
 382};
 383
 384#define LOCALLY_ENQUEUED 0x1
 385
 386#define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
 387
 388static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 389                                     const struct net_device *dev)
 390{
 391        unsigned int seq;
 392
 393        do {
 394                seq = read_seqbegin(&n->ha_lock);
 395                memcpy(dst, n->ha, dev->addr_len);
 396        } while (read_seqretry(&n->ha_lock, seq));
 397}
 398#endif
 399