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 <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
  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 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
 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 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
 129struct 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
 143struct 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
 151struct 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
 190extern void                     neigh_table_init(struct neigh_table *tbl);
 191extern void                     neigh_table_init_no_netlink(struct neigh_table *tbl);
 192extern int                      neigh_table_clear(struct neigh_table *tbl);
 193extern struct neighbour *       neigh_lookup(struct neigh_table *tbl,
 194                                             const void *pkey,
 195                                             struct net_device *dev);
 196extern struct neighbour *       neigh_lookup_nodev(struct neigh_table *tbl,
 197                                                   struct net *net,
 198                                                   const void *pkey);
 199extern struct neighbour *       neigh_create(struct neigh_table *tbl,
 200                                             const void *pkey,
 201                                             struct net_device *dev);
 202extern void                     neigh_destroy(struct neighbour *neigh);
 203extern int                      __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 204extern int                      neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, 
 205                                             u32 flags);
 206extern void                     neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 207extern int                      neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 208extern int                      neigh_resolve_output(struct sk_buff *skb);
 209extern int                      neigh_connected_output(struct sk_buff *skb);
 210extern int                      neigh_compat_output(struct sk_buff *skb);
 211extern struct neighbour         *neigh_event_ns(struct neigh_table *tbl,
 212                                                u8 *lladdr, void *saddr,
 213                                                struct net_device *dev);
 214
 215extern struct neigh_parms       *neigh_parms_alloc(struct net_device *dev, struct neigh_table *tbl);
 216extern void                     neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
 217
 218static inline
 219struct net                      *neigh_parms_net(const struct neigh_parms *parms)
 220{
 221        return read_pnet(&parms->net);
 222}
 223
 224extern unsigned long            neigh_rand_reach_time(unsigned long base);
 225
 226extern void                     pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 227                                               struct sk_buff *skb);
 228extern struct pneigh_entry      *pneigh_lookup(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev, int creat);
 229extern struct pneigh_entry      *__pneigh_lookup(struct neigh_table *tbl,
 230                                                 struct net *net,
 231                                                 const void *key,
 232                                                 struct net_device *dev);
 233extern int                      pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev);
 234
 235static inline
 236struct net                      *pneigh_net(const struct pneigh_entry *pneigh)
 237{
 238        return read_pnet(&pneigh->net);
 239}
 240
 241extern void neigh_app_ns(struct neighbour *n);
 242extern void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie);
 243extern void __neigh_for_each_release(struct neigh_table *tbl, int (*cb)(struct neighbour *));
 244extern void pneigh_for_each(struct neigh_table *tbl, void (*cb)(struct pneigh_entry *));
 245
 246struct 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};
 258extern void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, unsigned int);
 259extern void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 260extern void neigh_seq_stop(struct seq_file *, void *);
 261
 262extern int                      neigh_sysctl_register(struct net_device *dev, 
 263                                                      struct neigh_parms *p,
 264                                                      char *p_name,
 265                                                      proc_handler *proc_handler);
 266extern void                     neigh_sysctl_unregister(struct neigh_parms *p);
 267
 268static inline void __neigh_parms_put(struct neigh_parms *parms)
 269{
 270        atomic_dec(&parms->refcnt);
 271}
 272
 273static 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
 283static inline void neigh_release(struct neighbour *neigh)
 284{
 285        if (atomic_dec_and_test(&neigh->refcnt))
 286                neigh_destroy(neigh);
 287}
 288
 289static 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
 298static inline void neigh_confirm(struct neighbour *neigh)
 299{
 300        if (neigh)
 301                neigh->confirmed = jiffies;
 302}
 303
 304static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 305{
 306        unsigned long now = 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
 316static 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
 329static 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
 347static 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
 359static 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
 371struct 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
 380static 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
 391