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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         unsigned long table_fulls;      /* times even gc couldn't help */
129 };
130 
131 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
132 
133 struct neighbour {
134         struct neighbour __rcu  *next;
135         struct neigh_table      *tbl;
136         struct neigh_parms      *parms;
137         unsigned long           confirmed;
138         unsigned long           updated;
139         rwlock_t                lock;
140         atomic_t                refcnt;
141         struct sk_buff_head     arp_queue;
142         unsigned int            arp_queue_len_bytes;
143         struct timer_list       timer;
144         unsigned long           used;
145         atomic_t                probes;
146         __u8                    flags;
147         __u8                    nud_state;
148         __u8                    type;
149         __u8                    dead;
150         seqlock_t               ha_lock;
151         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
152         struct hh_cache         hh;
153         int                     (*output)(struct neighbour *, struct sk_buff *);
154         const struct neigh_ops  *ops;
155         struct rcu_head         rcu;
156         struct net_device       *dev;
157         u8                      primary_key[0];
158 };
159 
160 struct neigh_ops {
161         int                     family;
162         void                    (*solicit)(struct neighbour *, struct sk_buff *);
163         void                    (*error_report)(struct neighbour *, struct sk_buff *);
164         int                     (*output)(struct neighbour *, struct sk_buff *);
165         int                     (*connected_output)(struct neighbour *, struct sk_buff *);
166 };
167 
168 struct pneigh_entry {
169         struct pneigh_entry     *next;
170         possible_net_t          net;
171         struct net_device       *dev;
172         u8                      flags;
173         u8                      key[0];
174 };
175 
176 /*
177  *      neighbour table manipulation
178  */
179 
180 #define NEIGH_NUM_HASH_RND      4
181 
182 struct neigh_hash_table {
183         struct neighbour __rcu  **hash_buckets;
184         unsigned int            hash_shift;
185         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
186         struct rcu_head         rcu;
187 };
188 
189 
190 struct neigh_table {
191         int                     family;
192         int                     entry_size;
193         int                     key_len;
194         __be16                  protocol;
195         __u32                   (*hash)(const void *pkey,
196                                         const struct net_device *dev,
197                                         __u32 *hash_rnd);
198         bool                    (*key_eq)(const struct neighbour *, const void *pkey);
199         int                     (*constructor)(struct neighbour *);
200         int                     (*pconstructor)(struct pneigh_entry *);
201         void                    (*pdestructor)(struct pneigh_entry *);
202         void                    (*proxy_redo)(struct sk_buff *skb);
203         char                    *id;
204         struct neigh_parms      parms;
205         struct list_head        parms_list;
206         int                     gc_interval;
207         int                     gc_thresh1;
208         int                     gc_thresh2;
209         int                     gc_thresh3;
210         unsigned long           last_flush;
211         struct delayed_work     gc_work;
212         struct timer_list       proxy_timer;
213         struct sk_buff_head     proxy_queue;
214         atomic_t                entries;
215         rwlock_t                lock;
216         unsigned long           last_rand;
217         struct neigh_statistics __percpu *stats;
218         struct neigh_hash_table __rcu *nht;
219         struct pneigh_entry     **phash_buckets;
220 };
221 
222 enum {
223         NEIGH_ARP_TABLE = 0,
224         NEIGH_ND_TABLE = 1,
225         NEIGH_DN_TABLE = 2,
226         NEIGH_NR_TABLES,
227         NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
228 };
229 
230 static inline int neigh_parms_family(struct neigh_parms *p)
231 {
232         return p->tbl->family;
233 }
234 
235 #define NEIGH_PRIV_ALIGN        sizeof(long long)
236 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
237 
238 static inline void *neighbour_priv(const struct neighbour *n)
239 {
240         return (char *)n + n->tbl->entry_size;
241 }
242 
243 /* flags for neigh_update() */
244 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
245 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
246 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
247 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
248 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
249 
250 
251 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
252 {
253         return *(const u16 *)n->primary_key == *(const u16 *)pkey;
254 }
255 
256 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
257 {
258         return *(const u32 *)n->primary_key == *(const u32 *)pkey;
259 }
260 
261 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
262 {
263         const u32 *n32 = (const u32 *)n->primary_key;
264         const u32 *p32 = pkey;
265 
266         return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
267                 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
268 }
269 
270 static inline struct neighbour *___neigh_lookup_noref(
271         struct neigh_table *tbl,
272         bool (*key_eq)(const struct neighbour *n, const void *pkey),
273         __u32 (*hash)(const void *pkey,
274                       const struct net_device *dev,
275                       __u32 *hash_rnd),
276         const void *pkey,
277         struct net_device *dev)
278 {
279         struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
280         struct neighbour *n;
281         u32 hash_val;
282 
283         hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
284         for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
285              n != NULL;
286              n = rcu_dereference_bh(n->next)) {
287                 if (n->dev == dev && key_eq(n, pkey))
288                         return n;
289         }
290 
291         return NULL;
292 }
293 
294 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
295                                                      const void *pkey,
296                                                      struct net_device *dev)
297 {
298         return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
299 }
300 
301 void neigh_table_init(int index, struct neigh_table *tbl);
302 int neigh_table_clear(int index, struct neigh_table *tbl);
303 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
304                                struct net_device *dev);
305 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
306                                      const void *pkey);
307 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
308                                  struct net_device *dev, bool want_ref);
309 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
310                                              const void *pkey,
311                                              struct net_device *dev)
312 {
313         return __neigh_create(tbl, pkey, dev, true);
314 }
315 void neigh_destroy(struct neighbour *neigh);
316 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
317 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
318 void __neigh_set_probe_once(struct neighbour *neigh);
319 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
320 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
321 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
322 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
323 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
324 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
325                                                 u8 *lladdr, void *saddr,
326                                                 struct net_device *dev);
327 
328 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
329                                       struct neigh_table *tbl);
330 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
331 
332 static inline
333 struct net *neigh_parms_net(const struct neigh_parms *parms)
334 {
335         return read_pnet(&parms->net);
336 }
337 
338 unsigned long neigh_rand_reach_time(unsigned long base);
339 
340 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
341                     struct sk_buff *skb);
342 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
343                                    const void *key, struct net_device *dev,
344                                    int creat);
345 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
346                                      const void *key, struct net_device *dev);
347 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
348                   struct net_device *dev);
349 
350 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
351 {
352         return read_pnet(&pneigh->net);
353 }
354 
355 void neigh_app_ns(struct neighbour *n);
356 void neigh_for_each(struct neigh_table *tbl,
357                     void (*cb)(struct neighbour *, void *), void *cookie);
358 void __neigh_for_each_release(struct neigh_table *tbl,
359                               int (*cb)(struct neighbour *));
360 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
361 void pneigh_for_each(struct neigh_table *tbl,
362                      void (*cb)(struct pneigh_entry *));
363 
364 struct neigh_seq_state {
365         struct seq_net_private p;
366         struct neigh_table *tbl;
367         struct neigh_hash_table *nht;
368         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
369                                 struct neighbour *n, loff_t *pos);
370         unsigned int bucket;
371         unsigned int flags;
372 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
373 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
374 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
375 };
376 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
377                       unsigned int);
378 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
379 void neigh_seq_stop(struct seq_file *, void *);
380 
381 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
382                         void __user *buffer, size_t *lenp, loff_t *ppos);
383 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
384                                 void __user *buffer,
385                                 size_t *lenp, loff_t *ppos);
386 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
387                                    void __user *buffer,
388                                    size_t *lenp, loff_t *ppos);
389 
390 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
391                           proc_handler *proc_handler);
392 void neigh_sysctl_unregister(struct neigh_parms *p);
393 
394 static inline void __neigh_parms_put(struct neigh_parms *parms)
395 {
396         atomic_dec(&parms->refcnt);
397 }
398 
399 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
400 {
401         atomic_inc(&parms->refcnt);
402         return parms;
403 }
404 
405 /*
406  *      Neighbour references
407  */
408 
409 static inline void neigh_release(struct neighbour *neigh)
410 {
411         if (atomic_dec_and_test(&neigh->refcnt))
412                 neigh_destroy(neigh);
413 }
414 
415 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
416 {
417         if (neigh)
418                 atomic_inc(&neigh->refcnt);
419         return neigh;
420 }
421 
422 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
423 
424 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
425 {
426         unsigned long now = jiffies;
427         
428         if (neigh->used != now)
429                 neigh->used = now;
430         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
431                 return __neigh_event_send(neigh, skb);
432         return 0;
433 }
434 
435 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
436 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
437 {
438         unsigned int seq, hh_alen;
439 
440         do {
441                 seq = read_seqbegin(&hh->hh_lock);
442                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
443                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
444         } while (read_seqretry(&hh->hh_lock, seq));
445         return 0;
446 }
447 #endif
448 
449 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
450 {
451         unsigned int seq;
452         int hh_len;
453 
454         do {
455                 seq = read_seqbegin(&hh->hh_lock);
456                 hh_len = hh->hh_len;
457                 if (likely(hh_len <= HH_DATA_MOD)) {
458                         /* this is inlined by gcc */
459                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
460                 } else {
461                         int hh_alen = HH_DATA_ALIGN(hh_len);
462 
463                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
464                 }
465         } while (read_seqretry(&hh->hh_lock, seq));
466 
467         skb_push(skb, hh_len);
468         return dev_queue_xmit(skb);
469 }
470 
471 static inline struct neighbour *
472 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
473 {
474         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
475 
476         if (n || !creat)
477                 return n;
478 
479         n = neigh_create(tbl, pkey, dev);
480         return IS_ERR(n) ? NULL : n;
481 }
482 
483 static inline struct neighbour *
484 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
485   struct net_device *dev)
486 {
487         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
488 
489         if (n)
490                 return n;
491 
492         return neigh_create(tbl, pkey, dev);
493 }
494 
495 struct neighbour_cb {
496         unsigned long sched_next;
497         unsigned int flags;
498 };
499 
500 #define LOCALLY_ENQUEUED 0x1
501 
502 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
503 
504 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
505                                      const struct net_device *dev)
506 {
507         unsigned int seq;
508 
509         do {
510                 seq = read_seqbegin(&n->ha_lock);
511                 memcpy(dst, n->ha, dev->addr_len);
512         } while (read_seqretry(&n->ha_lock, seq));
513 }
514 
515 
516 #endif
517 

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