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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 list_head list;
 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         int                     family;
194         int                     entry_size;
195         int                     key_len;
196         __u32                   (*hash)(const void *pkey,
197                                         const struct net_device *dev,
198                                         __u32 *hash_rnd);
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 };
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 void neigh_table_init(int index, struct neigh_table *tbl);
250 int neigh_table_clear(int index, struct neigh_table *tbl);
251 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
252                                struct net_device *dev);
253 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
254                                      const void *pkey);
255 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
256                                  struct net_device *dev, bool want_ref);
257 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
258                                              const void *pkey,
259                                              struct net_device *dev)
260 {
261         return __neigh_create(tbl, pkey, dev, true);
262 }
263 void neigh_destroy(struct neighbour *neigh);
264 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
265 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
266 void __neigh_set_probe_once(struct neighbour *neigh);
267 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
268 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
269 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
270 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
271 int neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
272 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
273 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
274                                                 u8 *lladdr, void *saddr,
275                                                 struct net_device *dev);
276 
277 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
278                                       struct neigh_table *tbl);
279 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
280 
281 static inline
282 struct net *neigh_parms_net(const struct neigh_parms *parms)
283 {
284         return read_pnet(&parms->net);
285 }
286 
287 unsigned long neigh_rand_reach_time(unsigned long base);
288 
289 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
290                     struct sk_buff *skb);
291 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
292                                    const void *key, struct net_device *dev,
293                                    int creat);
294 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
295                                      const void *key, struct net_device *dev);
296 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
297                   struct net_device *dev);
298 
299 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
300 {
301         return read_pnet(&pneigh->net);
302 }
303 
304 void neigh_app_ns(struct neighbour *n);
305 void neigh_for_each(struct neigh_table *tbl,
306                     void (*cb)(struct neighbour *, void *), void *cookie);
307 void __neigh_for_each_release(struct neigh_table *tbl,
308                               int (*cb)(struct neighbour *));
309 void pneigh_for_each(struct neigh_table *tbl,
310                      void (*cb)(struct pneigh_entry *));
311 
312 struct neigh_seq_state {
313         struct seq_net_private p;
314         struct neigh_table *tbl;
315         struct neigh_hash_table *nht;
316         void *(*neigh_sub_iter)(struct neigh_seq_state *state,
317                                 struct neighbour *n, loff_t *pos);
318         unsigned int bucket;
319         unsigned int flags;
320 #define NEIGH_SEQ_NEIGH_ONLY    0x00000001
321 #define NEIGH_SEQ_IS_PNEIGH     0x00000002
322 #define NEIGH_SEQ_SKIP_NOARP    0x00000004
323 };
324 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
325                       unsigned int);
326 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
327 void neigh_seq_stop(struct seq_file *, void *);
328 
329 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
330                         void __user *buffer, size_t *lenp, loff_t *ppos);
331 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
332                                 void __user *buffer,
333                                 size_t *lenp, loff_t *ppos);
334 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
335                                    void __user *buffer,
336                                    size_t *lenp, loff_t *ppos);
337 
338 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
339                           proc_handler *proc_handler);
340 void neigh_sysctl_unregister(struct neigh_parms *p);
341 
342 static inline void __neigh_parms_put(struct neigh_parms *parms)
343 {
344         atomic_dec(&parms->refcnt);
345 }
346 
347 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
348 {
349         atomic_inc(&parms->refcnt);
350         return parms;
351 }
352 
353 /*
354  *      Neighbour references
355  */
356 
357 static inline void neigh_release(struct neighbour *neigh)
358 {
359         if (atomic_dec_and_test(&neigh->refcnt))
360                 neigh_destroy(neigh);
361 }
362 
363 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
364 {
365         if (neigh)
366                 atomic_inc(&neigh->refcnt);
367         return neigh;
368 }
369 
370 #define neigh_hold(n)   atomic_inc(&(n)->refcnt)
371 
372 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
373 {
374         unsigned long now = jiffies;
375         
376         if (neigh->used != now)
377                 neigh->used = now;
378         if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
379                 return __neigh_event_send(neigh, skb);
380         return 0;
381 }
382 
383 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
384 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
385 {
386         unsigned int seq, hh_alen;
387 
388         do {
389                 seq = read_seqbegin(&hh->hh_lock);
390                 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
391                 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
392         } while (read_seqretry(&hh->hh_lock, seq));
393         return 0;
394 }
395 #endif
396 
397 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
398 {
399         unsigned int seq;
400         int hh_len;
401 
402         do {
403                 seq = read_seqbegin(&hh->hh_lock);
404                 hh_len = hh->hh_len;
405                 if (likely(hh_len <= HH_DATA_MOD)) {
406                         /* this is inlined by gcc */
407                         memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
408                 } else {
409                         int hh_alen = HH_DATA_ALIGN(hh_len);
410 
411                         memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
412                 }
413         } while (read_seqretry(&hh->hh_lock, seq));
414 
415         skb_push(skb, hh_len);
416         return dev_queue_xmit(skb);
417 }
418 
419 static inline struct neighbour *
420 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
421 {
422         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
423 
424         if (n || !creat)
425                 return n;
426 
427         n = neigh_create(tbl, pkey, dev);
428         return IS_ERR(n) ? NULL : n;
429 }
430 
431 static inline struct neighbour *
432 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
433   struct net_device *dev)
434 {
435         struct neighbour *n = neigh_lookup(tbl, pkey, dev);
436 
437         if (n)
438                 return n;
439 
440         return neigh_create(tbl, pkey, dev);
441 }
442 
443 struct neighbour_cb {
444         unsigned long sched_next;
445         unsigned int flags;
446 };
447 
448 #define LOCALLY_ENQUEUED 0x1
449 
450 #define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)
451 
452 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
453                                      const struct net_device *dev)
454 {
455         unsigned int seq;
456 
457         do {
458                 seq = read_seqbegin(&n->ha_lock);
459                 memcpy(dst, n->ha, dev->addr_len);
460         } while (read_seqretry(&n->ha_lock, seq));
461 }
462 #endif
463 

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