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