1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _NET_NEIGHBOUR_H
3 #define _NET_NEIGHBOUR_H
4
5 #include <linux/neighbour.h>
6
7 /*
8 * Generic neighbour manipulation
9 *
10 * Authors:
11 * Pedro Roque <roque@di.fc.ul.pt>
12 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
13 *
14 * Changes:
15 *
16 * Harald Welte: <laforge@gnumonks.org>
17 * - Add neighbour cache statistics like rtstat
18 */
19
20 #include <linux/atomic.h>
21 #include <linux/refcount.h>
22 #include <linux/netdevice.h>
23 #include <linux/skbuff.h>
24 #include <linux/rcupdate.h>
25 #include <linux/seq_file.h>
26 #include <linux/bitmap.h>
27
28 #include <linux/err.h>
29 #include <linux/sysctl.h>
30 #include <linux/workqueue.h>
31 #include <net/rtnetlink.h>
32
33 /*
34 * NUD stands for "neighbor unreachability detection"
35 */
36
37 #define NUD_IN_TIMER (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
38 #define NUD_VALID (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
39 #define NUD_CONNECTED (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
40
41 struct neighbour;
42
43 enum {
44 NEIGH_VAR_MCAST_PROBES,
45 NEIGH_VAR_UCAST_PROBES,
46 NEIGH_VAR_APP_PROBES,
47 NEIGH_VAR_MCAST_REPROBES,
48 NEIGH_VAR_RETRANS_TIME,
49 NEIGH_VAR_BASE_REACHABLE_TIME,
50 NEIGH_VAR_DELAY_PROBE_TIME,
51 NEIGH_VAR_GC_STALETIME,
52 NEIGH_VAR_QUEUE_LEN_BYTES,
53 NEIGH_VAR_PROXY_QLEN,
54 NEIGH_VAR_ANYCAST_DELAY,
55 NEIGH_VAR_PROXY_DELAY,
56 NEIGH_VAR_LOCKTIME,
57 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
58 /* Following are used as a second way to access one of the above */
59 NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
60 NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
61 NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
62 /* Following are used by "default" only */
63 NEIGH_VAR_GC_INTERVAL,
64 NEIGH_VAR_GC_THRESH1,
65 NEIGH_VAR_GC_THRESH2,
66 NEIGH_VAR_GC_THRESH3,
67 NEIGH_VAR_MAX
68 };
69
70 struct neigh_parms {
71 possible_net_t net;
72 struct net_device *dev;
73 struct list_head list;
74 int (*neigh_setup)(struct neighbour *);
75 void (*neigh_cleanup)(struct neighbour *);
76 struct neigh_table *tbl;
77
78 void *sysctl_table;
79
80 int dead;
81 refcount_t refcnt;
82 struct rcu_head rcu_head;
83
84 int reachable_time;
85 int data[NEIGH_VAR_DATA_MAX];
86 DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
87 };
88
neigh_var_set(struct neigh_parms * p,int index,int val)89 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
90 {
91 set_bit(index, p->data_state);
92 p->data[index] = val;
93 }
94
95 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
96
97 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
98 * In other cases, NEIGH_VAR_SET should be used.
99 */
100 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
101 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
102
neigh_parms_data_state_setall(struct neigh_parms * p)103 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
104 {
105 bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
106 }
107
neigh_parms_data_state_cleanall(struct neigh_parms * p)108 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
109 {
110 bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
111 }
112
113 struct neigh_statistics {
114 unsigned long allocs; /* number of allocated neighs */
115 unsigned long destroys; /* number of destroyed neighs */
116 unsigned long hash_grows; /* number of hash resizes */
117
118 unsigned long res_failed; /* number of failed resolutions */
119
120 unsigned long lookups; /* number of lookups */
121 unsigned long hits; /* number of hits (among lookups) */
122
123 unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
124 unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
125
126 unsigned long periodic_gc_runs; /* number of periodic GC runs */
127 unsigned long forced_gc_runs; /* number of forced GC runs */
128
129 unsigned long unres_discards; /* number of unresolved drops */
130 unsigned long table_fulls; /* times even gc couldn't help */
131 };
132
133 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
134
135 struct neighbour {
136 struct neighbour __rcu *next;
137 struct neigh_table *tbl;
138 struct neigh_parms *parms;
139 unsigned long confirmed;
140 unsigned long updated;
141 rwlock_t lock;
142 refcount_t refcnt;
143 struct sk_buff_head arp_queue;
144 unsigned int arp_queue_len_bytes;
145 struct timer_list timer;
146 unsigned long used;
147 atomic_t probes;
148 __u8 flags;
149 __u8 nud_state;
150 __u8 type;
151 __u8 dead;
152 seqlock_t ha_lock;
153 unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
154 struct hh_cache hh;
155 int (*output)(struct neighbour *, struct sk_buff *);
156 const struct neigh_ops *ops;
157 struct rcu_head rcu;
158 struct net_device *dev;
159 u8 primary_key[0];
160 } __randomize_layout;
161
162 struct neigh_ops {
163 int family;
164 void (*solicit)(struct neighbour *, struct sk_buff *);
165 void (*error_report)(struct neighbour *, struct sk_buff *);
166 int (*output)(struct neighbour *, struct sk_buff *);
167 int (*connected_output)(struct neighbour *, struct sk_buff *);
168 };
169
170 struct pneigh_entry {
171 struct pneigh_entry *next;
172 possible_net_t net;
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 unsigned int entry_size;
195 unsigned int key_len;
196 __be16 protocol;
197 __u32 (*hash)(const void *pkey,
198 const struct net_device *dev,
199 __u32 *hash_rnd);
200 bool (*key_eq)(const struct neighbour *, const void *pkey);
201 int (*constructor)(struct neighbour *);
202 int (*pconstructor)(struct pneigh_entry *);
203 void (*pdestructor)(struct pneigh_entry *);
204 void (*proxy_redo)(struct sk_buff *skb);
205 char *id;
206 struct neigh_parms parms;
207 struct list_head parms_list;
208 int gc_interval;
209 int gc_thresh1;
210 int gc_thresh2;
211 int gc_thresh3;
212 unsigned long last_flush;
213 struct delayed_work gc_work;
214 struct timer_list proxy_timer;
215 struct sk_buff_head proxy_queue;
216 atomic_t entries;
217 rwlock_t lock;
218 unsigned long last_rand;
219 struct neigh_statistics __percpu *stats;
220 struct neigh_hash_table __rcu *nht;
221 struct pneigh_entry **phash_buckets;
222 };
223
224 enum {
225 NEIGH_ARP_TABLE = 0,
226 NEIGH_ND_TABLE = 1,
227 NEIGH_DN_TABLE = 2,
228 NEIGH_NR_TABLES,
229 NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
230 };
231
neigh_parms_family(struct neigh_parms * p)232 static inline int neigh_parms_family(struct neigh_parms *p)
233 {
234 return p->tbl->family;
235 }
236
237 #define NEIGH_PRIV_ALIGN sizeof(long long)
238 #define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN)
239
neighbour_priv(const struct neighbour * n)240 static inline void *neighbour_priv(const struct neighbour *n)
241 {
242 return (char *)n + n->tbl->entry_size;
243 }
244
245 /* flags for neigh_update() */
246 #define NEIGH_UPDATE_F_OVERRIDE 0x00000001
247 #define NEIGH_UPDATE_F_WEAK_OVERRIDE 0x00000002
248 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER 0x00000004
249 #define NEIGH_UPDATE_F_EXT_LEARNED 0x20000000
250 #define NEIGH_UPDATE_F_ISROUTER 0x40000000
251 #define NEIGH_UPDATE_F_ADMIN 0x80000000
252
253
neigh_key_eq16(const struct neighbour * n,const void * pkey)254 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
255 {
256 return *(const u16 *)n->primary_key == *(const u16 *)pkey;
257 }
258
neigh_key_eq32(const struct neighbour * n,const void * pkey)259 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
260 {
261 return *(const u32 *)n->primary_key == *(const u32 *)pkey;
262 }
263
neigh_key_eq128(const struct neighbour * n,const void * pkey)264 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
265 {
266 const u32 *n32 = (const u32 *)n->primary_key;
267 const u32 *p32 = pkey;
268
269 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
270 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
271 }
272
___neigh_lookup_noref(struct neigh_table * tbl,bool (* key_eq)(const struct neighbour * n,const void * pkey),__u32 (* hash)(const void * pkey,const struct net_device * dev,__u32 * hash_rnd),const void * pkey,struct net_device * dev)273 static inline struct neighbour *___neigh_lookup_noref(
274 struct neigh_table *tbl,
275 bool (*key_eq)(const struct neighbour *n, const void *pkey),
276 __u32 (*hash)(const void *pkey,
277 const struct net_device *dev,
278 __u32 *hash_rnd),
279 const void *pkey,
280 struct net_device *dev)
281 {
282 struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
283 struct neighbour *n;
284 u32 hash_val;
285
286 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
287 for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
288 n != NULL;
289 n = rcu_dereference_bh(n->next)) {
290 if (n->dev == dev && key_eq(n, pkey))
291 return n;
292 }
293
294 return NULL;
295 }
296
__neigh_lookup_noref(struct neigh_table * tbl,const void * pkey,struct net_device * dev)297 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
298 const void *pkey,
299 struct net_device *dev)
300 {
301 return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
302 }
303
304 void neigh_table_init(int index, struct neigh_table *tbl);
305 int neigh_table_clear(int index, struct neigh_table *tbl);
306 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
307 struct net_device *dev);
308 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
309 const void *pkey);
310 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
311 struct net_device *dev, bool want_ref);
neigh_create(struct neigh_table * tbl,const void * pkey,struct net_device * dev)312 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
313 const void *pkey,
314 struct net_device *dev)
315 {
316 return __neigh_create(tbl, pkey, dev, true);
317 }
318 void neigh_destroy(struct neighbour *neigh);
319 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
320 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
321 u32 nlmsg_pid);
322 void __neigh_set_probe_once(struct neighbour *neigh);
323 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
324 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
325 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
326 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
327 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
328 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
329 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
330 u8 *lladdr, void *saddr,
331 struct net_device *dev);
332
333 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
334 struct neigh_table *tbl);
335 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
336
337 static inline
neigh_parms_net(const struct neigh_parms * parms)338 struct net *neigh_parms_net(const struct neigh_parms *parms)
339 {
340 return read_pnet(&parms->net);
341 }
342
343 unsigned long neigh_rand_reach_time(unsigned long base);
344
345 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
346 struct sk_buff *skb);
347 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
348 const void *key, struct net_device *dev,
349 int creat);
350 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
351 const void *key, struct net_device *dev);
352 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
353 struct net_device *dev);
354
pneigh_net(const struct pneigh_entry * pneigh)355 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
356 {
357 return read_pnet(&pneigh->net);
358 }
359
360 void neigh_app_ns(struct neighbour *n);
361 void neigh_for_each(struct neigh_table *tbl,
362 void (*cb)(struct neighbour *, void *), void *cookie);
363 void __neigh_for_each_release(struct neigh_table *tbl,
364 int (*cb)(struct neighbour *));
365 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
366 void pneigh_for_each(struct neigh_table *tbl,
367 void (*cb)(struct pneigh_entry *));
368
369 struct neigh_seq_state {
370 struct seq_net_private p;
371 struct neigh_table *tbl;
372 struct neigh_hash_table *nht;
373 void *(*neigh_sub_iter)(struct neigh_seq_state *state,
374 struct neighbour *n, loff_t *pos);
375 unsigned int bucket;
376 unsigned int flags;
377 #define NEIGH_SEQ_NEIGH_ONLY 0x00000001
378 #define NEIGH_SEQ_IS_PNEIGH 0x00000002
379 #define NEIGH_SEQ_SKIP_NOARP 0x00000004
380 };
381 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
382 unsigned int);
383 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
384 void neigh_seq_stop(struct seq_file *, void *);
385
386 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
387 void __user *buffer, size_t *lenp, loff_t *ppos);
388 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
389 void __user *buffer,
390 size_t *lenp, loff_t *ppos);
391 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
392 void __user *buffer,
393 size_t *lenp, loff_t *ppos);
394
395 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
396 proc_handler *proc_handler);
397 void neigh_sysctl_unregister(struct neigh_parms *p);
398
__neigh_parms_put(struct neigh_parms * parms)399 static inline void __neigh_parms_put(struct neigh_parms *parms)
400 {
401 refcount_dec(&parms->refcnt);
402 }
403
neigh_parms_clone(struct neigh_parms * parms)404 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
405 {
406 refcount_inc(&parms->refcnt);
407 return parms;
408 }
409
410 /*
411 * Neighbour references
412 */
413
neigh_release(struct neighbour * neigh)414 static inline void neigh_release(struct neighbour *neigh)
415 {
416 if (refcount_dec_and_test(&neigh->refcnt))
417 neigh_destroy(neigh);
418 }
419
neigh_clone(struct neighbour * neigh)420 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
421 {
422 if (neigh)
423 refcount_inc(&neigh->refcnt);
424 return neigh;
425 }
426
427 #define neigh_hold(n) refcount_inc(&(n)->refcnt)
428
neigh_event_send(struct neighbour * neigh,struct sk_buff * skb)429 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
430 {
431 unsigned long now = jiffies;
432
433 if (neigh->used != now)
434 neigh->used = now;
435 if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
436 return __neigh_event_send(neigh, skb);
437 return 0;
438 }
439
440 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
neigh_hh_bridge(struct hh_cache * hh,struct sk_buff * skb)441 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
442 {
443 unsigned int seq, hh_alen;
444
445 do {
446 seq = read_seqbegin(&hh->hh_lock);
447 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
448 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
449 } while (read_seqretry(&hh->hh_lock, seq));
450 return 0;
451 }
452 #endif
453
neigh_hh_output(const struct hh_cache * hh,struct sk_buff * skb)454 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
455 {
456 unsigned int seq;
457 unsigned int hh_len;
458
459 do {
460 seq = read_seqbegin(&hh->hh_lock);
461 hh_len = hh->hh_len;
462 if (likely(hh_len <= HH_DATA_MOD)) {
463 /* this is inlined by gcc */
464 memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
465 } else {
466 unsigned int hh_alen = HH_DATA_ALIGN(hh_len);
467
468 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
469 }
470 } while (read_seqretry(&hh->hh_lock, seq));
471
472 skb_push(skb, hh_len);
473 return dev_queue_xmit(skb);
474 }
475
neigh_output(struct neighbour * n,struct sk_buff * skb)476 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb)
477 {
478 const struct hh_cache *hh = &n->hh;
479
480 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
481 return neigh_hh_output(hh, skb);
482 else
483 return n->output(n, skb);
484 }
485
486 static inline struct neighbour *
__neigh_lookup(struct neigh_table * tbl,const void * pkey,struct net_device * dev,int creat)487 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
488 {
489 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
490
491 if (n || !creat)
492 return n;
493
494 n = neigh_create(tbl, pkey, dev);
495 return IS_ERR(n) ? NULL : n;
496 }
497
498 static inline struct neighbour *
__neigh_lookup_errno(struct neigh_table * tbl,const void * pkey,struct net_device * dev)499 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
500 struct net_device *dev)
501 {
502 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
503
504 if (n)
505 return n;
506
507 return neigh_create(tbl, pkey, dev);
508 }
509
510 struct neighbour_cb {
511 unsigned long sched_next;
512 unsigned int flags;
513 };
514
515 #define LOCALLY_ENQUEUED 0x1
516
517 #define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb)
518
neigh_ha_snapshot(char * dst,const struct neighbour * n,const struct net_device * dev)519 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
520 const struct net_device *dev)
521 {
522 unsigned int seq;
523
524 do {
525 seq = read_seqbegin(&n->ha_lock);
526 memcpy(dst, n->ha, dev->addr_len);
527 } while (read_seqretry(&n->ha_lock, seq));
528 }
529
neigh_update_ext_learned(struct neighbour * neigh,u32 flags,int * notify)530 static inline void neigh_update_ext_learned(struct neighbour *neigh, u32 flags,
531 int *notify)
532 {
533 u8 ndm_flags = 0;
534
535 if (!(flags & NEIGH_UPDATE_F_ADMIN))
536 return;
537
538 ndm_flags |= (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0;
539 if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) {
540 if (ndm_flags & NTF_EXT_LEARNED)
541 neigh->flags |= NTF_EXT_LEARNED;
542 else
543 neigh->flags &= ~NTF_EXT_LEARNED;
544 *notify = 1;
545 }
546 }
547 #endif
548
