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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_RETRANS_TIME,
 46         NEIGH_VAR_BASE_REACHABLE_TIME,
 47         NEIGH_VAR_DELAY_PROBE_TIME,
 48         NEIGH_VAR_GC_STALETIME,
 49         NEIGH_VAR_QUEUE_LEN_BYTES,
 50         NEIGH_VAR_PROXY_QLEN,
 51         NEIGH_VAR_ANYCAST_DELAY,
 52         NEIGH_VAR_PROXY_DELAY,
 53         NEIGH_VAR_LOCKTIME,
 54 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
 55         /* Following are used as a second way to access one of the above */
 56         NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
 57         NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
 58         NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
 59         /* Following are used by "default" only */
 60         NEIGH_VAR_GC_INTERVAL,
 61         NEIGH_VAR_GC_THRESH1,
 62         NEIGH_VAR_GC_THRESH2,
 63         NEIGH_VAR_GC_THRESH3,
 64         NEIGH_VAR_MAX
 65 };
 66 
 67 struct neigh_parms {
 68 #ifdef CONFIG_NET_NS
 69         struct net *net;
 70 #endif
 71         struct net_device *dev;
 72         struct neigh_parms *next;
 73         int     (*neigh_setup)(struct neighbour *);
 74         void    (*neigh_cleanup)(struct neighbour *);
 75         struct neigh_table *tbl;
 76 
 77         void    *sysctl_table;
 78 
 79         int dead;
 80         atomic_t refcnt;
 81         struct rcu_head rcu_head;
 82 
 83         int     reachable_time;
 84         int     data[NEIGH_VAR_DATA_MAX];
 85         DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
 86 };
 87 
 88 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
 89 {
 90         set_bit(index, p->data_state);
 91         p->data[index] = val;
 92 }
 93 
 94 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
 95 
 96 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
 97  * In other cases, NEIGH_VAR_SET should be used.
 98  */
 99 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
100 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
101 
102 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
103 {
104         bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
105 }
106 
107 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
108 {
109         bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
110 }
111 
112 struct neigh_statistics {
113         unsigned long allocs;           /* number of allocated neighs */
114         unsigned long destroys;         /* number of destroyed neighs */
115         unsigned long hash_grows;       /* number of hash resizes */
116 
117         unsigned long res_failed;       /* number of failed resolutions */
118 
119         unsigned long lookups;          /* number of lookups */
120         unsigned long hits;             /* number of hits (among lookups) */
121 
122         unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
123         unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
124 
125         unsigned long periodic_gc_runs; /* number of periodic GC runs */
126         unsigned long forced_gc_runs;   /* number of forced GC runs */
127 
128         unsigned long unres_discards;   /* number of unresolved drops */
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 #ifdef CONFIG_NET_NS
171         struct net              *net;
172 #endif
173         struct net_device       *dev;
174         u8                      flags;
175         u8                      key[0];
176 };
177 
178 /*
179  *      neighbour table manipulation
180  */
181 
182 #define NEIGH_NUM_HASH_RND      4
183 
184 struct neigh_hash_table {
185         struct neighbour __rcu  **hash_buckets;
186         unsigned int            hash_shift;
187         __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
188         struct rcu_head         rcu;
189 };
190 
191 
192 struct neigh_table {
193         struct neigh_table      *next;
194         int                     family;
195         int                     entry_size;
196         int                     key_len;
197         __u32                   (*hash)(const void *pkey,
198                                         const struct net_device *dev,
199                                         __u32 *hash_rnd);
200         int                     (*constructor)(struct neighbour *);
201         int                     (*pconstructor)(struct pneigh_entry *);
202         void                    (*pdestructor)(struct pneigh_entry *);
203         void                    (*proxy_redo)(struct sk_buff *skb);
204         char                    *id;
205         struct neigh_parms      parms;
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 static inline int neigh_parms_family(struct neigh_parms *p)
223 {
224         return p->tbl->family;
225 }
226 
227 #define NEIGH_PRIV_ALIGN        sizeof(long long)
228 #define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)
229 
230 static inline void *neighbour_priv(const struct neighbour *n)
231 {
232         return (char *)n + n->tbl->entry_size;
233 }
234 
235 /* flags for neigh_update() */
236 #define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
237 #define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
238 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
239 #define NEIGH_UPDATE_F_ISROUTER                 0x40000000
240 #define NEIGH_UPDATE_F_ADMIN                    0x80000000
241 
242 void neigh_table_init(struct neigh_table *tbl);
243 int neigh_table_clear(struct neigh_table *tbl);
244 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
245                                struct net_device *dev);
246 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
247                                      const void *pkey);
248 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
249                                  struct net_device *dev, bool want_ref);
250 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
251                                              const void *pkey,
252                                              struct net_device *dev)
253 {
254         return __neigh_create(tbl, pkey, dev, true);
255 }
256 void neigh_destroy(struct neighbour *neigh);
257 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
258 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
259 void __neigh_set_probe_once(struct neighbour *neigh);
260 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
261 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
262 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
263 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
264 int neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
265 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
266 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
267                                                 u8 *lladdr, void *saddr,
268                                                 struct net_device *dev);
269 
270 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
271                                       struct neigh_table *tbl);
272 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
273 
274 static inline
275 struct net *neigh_parms_net(const struct neigh_parms *parms)
276 {
277         return read_pnet(&parms->net);
278 }
279 
280 unsigned long neigh_rand_reach_time(unsigned long base);
281 
282 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
283                     struct sk_buff *skb);
284 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
285                                    const void *key, struct net_device *dev,
286                                    int creat);
287 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
288                                      const void *key, struct net_device *dev);
289 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
290                   struct net_device *dev);
291 
292 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
293 {
294         return read_pnet(&pneigh->net);
295 }
296 
297 void neigh_app_ns(struct neighbour *n);
298 void neigh_for_each(struct neigh_table *tbl,
299                     void (*cb)(struct neighbour *, void *), void *cookie);
300 void __neigh_for_each_release(struct neigh_table *tbl,
301                               int (*cb)(struct neighbour *));
302 void pneigh_for_each(struct neigh_table *tbl,
303                      void (*cb)(struct pneigh_entry *));
304 
305 struct neigh_seq_state {
306         struct seq_net_private p;
307         struct neigh_table *tbl;
308         struct neigh_hash_table *nht;
309         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
310                                 struct neighbour *n, loff_t *pos);
311         unsigned int bucket;
312         unsigned int flags;
313 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
314 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
315 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
316 };
317 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
318                       unsigned int);
319 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
320 void neigh_seq_stop(struct seq_file *, void *);
321 
322 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
323                         void __user *buffer, size_t *lenp, loff_t *ppos);
324 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
325                                 void __user *buffer,
326                                 size_t *lenp, loff_t *ppos);
327 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
328                                    void __user *buffer,
329                                    size_t *lenp, loff_t *ppos);
330 
331 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
332                           proc_handler *proc_handler);
333 void neigh_sysctl_unregister(struct neigh_parms *p);
334 
335 static inline void __neigh_parms_put(struct neigh_parms *parms)
336 {
337         atomic_dec(&parms->refcnt);
338 }
339 
340 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
341 {
342         atomic_inc(&parms->refcnt);
343         return parms;
344 }
345 
346 /*
347  *      Neighbour references
348  */
349 
350 static inline void neigh_release(struct neighbour *neigh)
351 {
352         if (atomic_dec_and_test(&neigh->refcnt))
353                 neigh_destroy(neigh);
354 }
355 
356 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
357 {
358         if (neigh)
359                 atomic_inc(&neigh->refcnt);
360         return neigh;
361 }
362 
363 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
364 
365 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
366 {
367         unsigned long now = jiffies;
368         
369         if (neigh->used != now)
370                 neigh->used = now;
371         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
372                 return __neigh_event_send(neigh, skb);
373         return 0;
374 }
375 
376 #ifdef CONFIG_BRIDGE_NETFILTER
377 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
378 {
379         unsigned int seq, hh_alen;
380 
381         do {
382                 seq = read_seqbegin(&hh->hh_lock);
383                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
384                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
385         } while (read_seqretry(&hh->hh_lock, seq));
386         return 0;
387 }
388 #endif
389 
390 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
391 {
392         unsigned int seq;
393         int hh_len;
394 
395         do {
396                 seq = read_seqbegin(&hh->hh_lock);
397                 hh_len = hh->hh_len;
398                 if (likely(hh_len <= HH_DATA_MOD)) {
399                         /* this is inlined by gcc */
400                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
401                 } else {
402                         int hh_alen = HH_DATA_ALIGN(hh_len);
403 
404                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
405                 }
406         } while (read_seqretry(&hh->hh_lock, seq));
407 
408         skb_push(skb, hh_len);
409         return dev_queue_xmit(skb);
410 }
411 
412 static inline struct neighbour *
413 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
414 {
415         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
416 
417         if (n || !creat)
418                 return n;
419 
420         n = neigh_create(tbl, pkey, dev);
421         return IS_ERR(n) ? NULL : n;
422 }
423 
424 static inline struct neighbour *
425 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
426   struct net_device *dev)
427 {
428         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
429 
430         if (n)
431                 return n;
432 
433         return neigh_create(tbl, pkey, dev);
434 }
435 
436 struct neighbour_cb {
437         unsigned long sched_next;
438         unsigned int flags;
439 };
440 
441 #define LOCALLY_ENQUEUED 0x1
442 
443 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
444 
445 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
446                                      const struct net_device *dev)
447 {
448         unsigned int seq;
449 
450         do {
451                 seq = read_seqbegin(&n->ha_lock);
452                 memcpy(dst, n->ha, dev->addr_len);
453         } while (read_seqretry(&n->ha_lock, seq));
454 }
455 #endif
456 

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