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Linux/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_MCAST_REPROBES,
 46         NEIGH_VAR_RETRANS_TIME,
 47         NEIGH_VAR_BASE_REACHABLE_TIME,
 48         NEIGH_VAR_DELAY_PROBE_TIME,
 49         NEIGH_VAR_GC_STALETIME,
 50         NEIGH_VAR_QUEUE_LEN_BYTES,
 51         NEIGH_VAR_PROXY_QLEN,
 52         NEIGH_VAR_ANYCAST_DELAY,
 53         NEIGH_VAR_PROXY_DELAY,
 54         NEIGH_VAR_LOCKTIME,
 55 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
 56         /* Following are used as a second way to access one of the above */
 57         NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
 58         NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
 59         NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
 60         /* Following are used by "default" only */
 61         NEIGH_VAR_GC_INTERVAL,
 62         NEIGH_VAR_GC_THRESH1,
 63         NEIGH_VAR_GC_THRESH2,
 64         NEIGH_VAR_GC_THRESH3,
 65         NEIGH_VAR_MAX
 66 };
 67 
 68 struct neigh_parms {
 69         possible_net_t net;
 70         struct net_device *dev;
 71         struct list_head list;
 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         DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
 85 };
 86 
 87 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
 88 {
 89         set_bit(index, p->data_state);
 90         p->data[index] = val;
 91 }
 92 
 93 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
 94 
 95 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
 96  * In other cases, NEIGH_VAR_SET should be used.
 97  */
 98 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
 99 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
100 
101 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
102 {
103         bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
104 }
105 
106 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
107 {
108         bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
109 }
110 
111 struct neigh_statistics {
112         unsigned long allocs;           /* number of allocated neighs */
113         unsigned long destroys;         /* number of destroyed neighs */
114         unsigned long hash_grows;       /* number of hash resizes */
115 
116         unsigned long res_failed;       /* number of failed resolutions */
117 
118         unsigned long lookups;          /* number of lookups */
119         unsigned long hits;             /* number of hits (among lookups) */
120 
121         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
122         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
123 
124         unsigned long periodic_gc_runs; /* number of periodic GC runs */
125         unsigned long forced_gc_runs;   /* number of forced GC runs */
126 
127         unsigned long unres_discards;   /* number of unresolved drops */
128 };
129 
130 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
131 
132 struct neighbour {
133         struct neighbour __rcu  *next;
134         struct neigh_table      *tbl;
135         struct neigh_parms      *parms;
136         unsigned long           confirmed;
137         unsigned long           updated;
138         rwlock_t                lock;
139         atomic_t                refcnt;
140         struct sk_buff_head     arp_queue;
141         unsigned int            arp_queue_len_bytes;
142         struct timer_list       timer;
143         unsigned long           used;
144         atomic_t                probes;
145         __u8                    flags;
146         __u8                    nud_state;
147         __u8                    type;
148         __u8                    dead;
149         seqlock_t               ha_lock;
150         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
151         struct hh_cache         hh;
152         int                     (*output)(struct neighbour *, struct sk_buff *);
153         const struct neigh_ops  *ops;
154         struct rcu_head         rcu;
155         struct net_device       *dev;
156         u8                      primary_key[0];
157 };
158 
159 struct neigh_ops {
160         int                     family;
161         void                    (*solicit)(struct neighbour *, struct sk_buff *);
162         void                    (*error_report)(struct neighbour *, struct sk_buff *);
163         int                     (*output)(struct neighbour *, struct sk_buff *);
164         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
165 };
166 
167 struct pneigh_entry {
168         struct pneigh_entry     *next;
169         possible_net_t          net;
170         struct net_device       *dev;
171         u8                      flags;
172         u8                      key[0];
173 };
174 
175 /*
176  *      neighbour table manipulation
177  */
178 
179 #define NEIGH_NUM_HASH_RND      4
180 
181 struct neigh_hash_table {
182         struct neighbour __rcu  **hash_buckets;
183         unsigned int            hash_shift;
184         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
185         struct rcu_head         rcu;
186 };
187 
188 
189 struct neigh_table {
190         int                     family;
191         int                     entry_size;
192         int                     key_len;
193         __be16                  protocol;
194         __u32                   (*hash)(const void *pkey,
195                                         const struct net_device *dev,
196                                         __u32 *hash_rnd);
197         bool                    (*key_eq)(const struct neighbour *, const void *pkey);
198         int                     (*constructor)(struct neighbour *);
199         int                     (*pconstructor)(struct pneigh_entry *);
200         void                    (*pdestructor)(struct pneigh_entry *);
201         void                    (*proxy_redo)(struct sk_buff *skb);
202         char                    *id;
203         struct neigh_parms      parms;
204         struct list_head        parms_list;
205         int                     gc_interval;
206         int                     gc_thresh1;
207         int                     gc_thresh2;
208         int                     gc_thresh3;
209         unsigned long           last_flush;
210         struct delayed_work     gc_work;
211         struct timer_list       proxy_timer;
212         struct sk_buff_head     proxy_queue;
213         atomic_t                entries;
214         rwlock_t                lock;
215         unsigned long           last_rand;
216         struct neigh_statistics __percpu *stats;
217         struct neigh_hash_table __rcu *nht;
218         struct pneigh_entry     **phash_buckets;
219 };
220 
221 enum {
222         NEIGH_ARP_TABLE = 0,
223         NEIGH_ND_TABLE = 1,
224         NEIGH_DN_TABLE = 2,
225         NEIGH_NR_TABLES,
226         NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
227 };
228 
229 static inline int neigh_parms_family(struct neigh_parms *p)
230 {
231         return p->tbl->family;
232 }
233 
234 #define NEIGH_PRIV_ALIGN        sizeof(long long)
235 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
236 
237 static inline void *neighbour_priv(const struct neighbour *n)
238 {
239         return (char *)n + n->tbl->entry_size;
240 }
241 
242 /* flags for neigh_update() */
243 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
244 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
245 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
246 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
247 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
248 
249 
250 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
251 {
252         return *(const u16 *)n->primary_key == *(const u16 *)pkey;
253 }
254 
255 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
256 {
257         return *(const u32 *)n->primary_key == *(const u32 *)pkey;
258 }
259 
260 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
261 {
262         const u32 *n32 = (const u32 *)n->primary_key;
263         const u32 *p32 = pkey;
264 
265         return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
266                 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
267 }
268 
269 static inline struct neighbour *___neigh_lookup_noref(
270         struct neigh_table *tbl,
271         bool (*key_eq)(const struct neighbour *n, const void *pkey),
272         __u32 (*hash)(const void *pkey,
273                       const struct net_device *dev,
274                       __u32 *hash_rnd),
275         const void *pkey,
276         struct net_device *dev)
277 {
278         struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
279         struct neighbour *n;
280         u32 hash_val;
281 
282         hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
283         for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
284              n != NULL;
285              n = rcu_dereference_bh(n->next)) {
286                 if (n->dev == dev && key_eq(n, pkey))
287                         return n;
288         }
289 
290         return NULL;
291 }
292 
293 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
294                                                      const void *pkey,
295                                                      struct net_device *dev)
296 {
297         return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
298 }
299 
300 void neigh_table_init(int index, struct neigh_table *tbl);
301 int neigh_table_clear(int index, struct neigh_table *tbl);
302 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
303                                struct net_device *dev);
304 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
305                                      const void *pkey);
306 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
307                                  struct net_device *dev, bool want_ref);
308 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
309                                              const void *pkey,
310                                              struct net_device *dev)
311 {
312         return __neigh_create(tbl, pkey, dev, true);
313 }
314 void neigh_destroy(struct neighbour *neigh);
315 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
316 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
317 void __neigh_set_probe_once(struct neighbour *neigh);
318 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
319 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
320 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
321 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
322 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
323 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
324                                                 u8 *lladdr, void *saddr,
325                                                 struct net_device *dev);
326 
327 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
328                                       struct neigh_table *tbl);
329 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
330 
331 static inline
332 struct net *neigh_parms_net(const struct neigh_parms *parms)
333 {
334         return read_pnet(&parms->net);
335 }
336 
337 unsigned long neigh_rand_reach_time(unsigned long base);
338 
339 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
340                     struct sk_buff *skb);
341 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
342                                    const void *key, struct net_device *dev,
343                                    int creat);
344 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
345                                      const void *key, struct net_device *dev);
346 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
347                   struct net_device *dev);
348 
349 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
350 {
351         return read_pnet(&pneigh->net);
352 }
353 
354 void neigh_app_ns(struct neighbour *n);
355 void neigh_for_each(struct neigh_table *tbl,
356                     void (*cb)(struct neighbour *, void *), void *cookie);
357 void __neigh_for_each_release(struct neigh_table *tbl,
358                               int (*cb)(struct neighbour *));
359 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
360 void pneigh_for_each(struct neigh_table *tbl,
361                      void (*cb)(struct pneigh_entry *));
362 
363 struct neigh_seq_state {
364         struct seq_net_private p;
365         struct neigh_table *tbl;
366         struct neigh_hash_table *nht;
367         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
368                                 struct neighbour *n, loff_t *pos);
369         unsigned int bucket;
370         unsigned int flags;
371 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
372 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
373 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
374 };
375 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
376                       unsigned int);
377 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
378 void neigh_seq_stop(struct seq_file *, void *);
379 
380 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
381                         void __user *buffer, size_t *lenp, loff_t *ppos);
382 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
383                                 void __user *buffer,
384                                 size_t *lenp, loff_t *ppos);
385 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
386                                    void __user *buffer,
387                                    size_t *lenp, loff_t *ppos);
388 
389 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
390                           proc_handler *proc_handler);
391 void neigh_sysctl_unregister(struct neigh_parms *p);
392 
393 static inline void __neigh_parms_put(struct neigh_parms *parms)
394 {
395         atomic_dec(&parms->refcnt);
396 }
397 
398 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
399 {
400         atomic_inc(&parms->refcnt);
401         return parms;
402 }
403 
404 /*
405  *      Neighbour references
406  */
407 
408 static inline void neigh_release(struct neighbour *neigh)
409 {
410         if (atomic_dec_and_test(&neigh->refcnt))
411                 neigh_destroy(neigh);
412 }
413 
414 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
415 {
416         if (neigh)
417                 atomic_inc(&neigh->refcnt);
418         return neigh;
419 }
420 
421 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
422 
423 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
424 {
425         unsigned long now = jiffies;
426         
427         if (neigh->used != now)
428                 neigh->used = now;
429         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
430                 return __neigh_event_send(neigh, skb);
431         return 0;
432 }
433 
434 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
435 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
436 {
437         unsigned int seq, hh_alen;
438 
439         do {
440                 seq = read_seqbegin(&hh->hh_lock);
441                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
442                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
443         } while (read_seqretry(&hh->hh_lock, seq));
444         return 0;
445 }
446 #endif
447 
448 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
449 {
450         unsigned int seq;
451         int hh_len;
452 
453         do {
454                 seq = read_seqbegin(&hh->hh_lock);
455                 hh_len = hh->hh_len;
456                 if (likely(hh_len <= HH_DATA_MOD)) {
457                         /* this is inlined by gcc */
458                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
459                 } else {
460                         int hh_alen = HH_DATA_ALIGN(hh_len);
461 
462                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
463                 }
464         } while (read_seqretry(&hh->hh_lock, seq));
465 
466         skb_push(skb, hh_len);
467         return dev_queue_xmit(skb);
468 }
469 
470 static inline struct neighbour *
471 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
472 {
473         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
474 
475         if (n || !creat)
476                 return n;
477 
478         n = neigh_create(tbl, pkey, dev);
479         return IS_ERR(n) ? NULL : n;
480 }
481 
482 static inline struct neighbour *
483 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
484   struct net_device *dev)
485 {
486         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
487 
488         if (n)
489                 return n;
490 
491         return neigh_create(tbl, pkey, dev);
492 }
493 
494 struct neighbour_cb {
495         unsigned long sched_next;
496         unsigned int flags;
497 };
498 
499 #define LOCALLY_ENQUEUED 0x1
500 
501 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
502 
503 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
504                                      const struct net_device *dev)
505 {
506         unsigned int seq;
507 
508         do {
509                 seq = read_seqbegin(&n->ha_lock);
510                 memcpy(dst, n->ha, dev->addr_len);
511         } while (read_seqretry(&n->ha_lock, seq));
512 }
513 
514 
515 #endif
516 

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