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 struct neigh_table *tbl;
76
77 void *sysctl_table;
78
79 int dead;
80 refcount_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
neigh_var_set(struct neigh_parms * p,int index,int val)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
neigh_parms_data_state_setall(struct neigh_parms * p)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
neigh_parms_data_state_cleanall(struct neigh_parms * p)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 unsigned long table_fulls; /* times even gc couldn't help */
130 };
131
132 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
133
134 struct neighbour {
135 struct neighbour __rcu *next;
136 struct neigh_table *tbl;
137 struct neigh_parms *parms;
138 unsigned long confirmed;
139 unsigned long updated;
140 rwlock_t lock;
141 refcount_t refcnt;
142 unsigned int arp_queue_len_bytes;
143 struct sk_buff_head arp_queue;
144 struct timer_list timer;
145 unsigned long used;
146 atomic_t probes;
147 __u8 flags;
148 __u8 nud_state;
149 __u8 type;
150 __u8 dead;
151 u8 protocol;
152 seqlock_t ha_lock;
153 unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
154 struct hh_cache hh;
155 int (*output)(struct neighbour *, struct sk_buff *);
156 const struct neigh_ops *ops;
157 struct list_head gc_list;
158 struct rcu_head rcu;
159 struct net_device *dev;
160 u8 primary_key[0];
161 } __randomize_layout;
162
163 struct neigh_ops {
164 int family;
165 void (*solicit)(struct neighbour *, struct sk_buff *);
166 void (*error_report)(struct neighbour *, struct sk_buff *);
167 int (*output)(struct neighbour *, struct sk_buff *);
168 int (*connected_output)(struct neighbour *, struct sk_buff *);
169 };
170
171 struct pneigh_entry {
172 struct pneigh_entry *next;
173 possible_net_t net;
174 struct net_device *dev;
175 u8 flags;
176 u8 protocol;
177 u8 key[0];
178 };
179
180 /*
181 * neighbour table manipulation
182 */
183
184 #define NEIGH_NUM_HASH_RND 4
185
186 struct neigh_hash_table {
187 struct neighbour __rcu **hash_buckets;
188 unsigned int hash_shift;
189 __u32 hash_rnd[NEIGH_NUM_HASH_RND];
190 struct rcu_head rcu;
191 };
192
193
194 struct neigh_table {
195 int family;
196 unsigned int entry_size;
197 unsigned int key_len;
198 __be16 protocol;
199 __u32 (*hash)(const void *pkey,
200 const struct net_device *dev,
201 __u32 *hash_rnd);
202 bool (*key_eq)(const struct neighbour *, const void *pkey);
203 int (*constructor)(struct neighbour *);
204 int (*pconstructor)(struct pneigh_entry *);
205 void (*pdestructor)(struct pneigh_entry *);
206 void (*proxy_redo)(struct sk_buff *skb);
207 bool (*allow_add)(const struct net_device *dev,
208 struct netlink_ext_ack *extack);
209 char *id;
210 struct neigh_parms parms;
211 struct list_head parms_list;
212 int gc_interval;
213 int gc_thresh1;
214 int gc_thresh2;
215 int gc_thresh3;
216 unsigned long last_flush;
217 struct delayed_work gc_work;
218 struct timer_list proxy_timer;
219 struct sk_buff_head proxy_queue;
220 atomic_t entries;
221 atomic_t gc_entries;
222 struct list_head gc_list;
223 rwlock_t lock;
224 unsigned long last_rand;
225 struct neigh_statistics __percpu *stats;
226 struct neigh_hash_table __rcu *nht;
227 struct pneigh_entry **phash_buckets;
228 };
229
230 enum {
231 NEIGH_ARP_TABLE = 0,
232 NEIGH_ND_TABLE = 1,
233 NEIGH_DN_TABLE = 2,
234 NEIGH_NR_TABLES,
235 NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
236 };
237
neigh_parms_family(struct neigh_parms * p)238 static inline int neigh_parms_family(struct neigh_parms *p)
239 {
240 return p->tbl->family;
241 }
242
243 #define NEIGH_PRIV_ALIGN sizeof(long long)
244 #define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN)
245
neighbour_priv(const struct neighbour * n)246 static inline void *neighbour_priv(const struct neighbour *n)
247 {
248 return (char *)n + n->tbl->entry_size;
249 }
250
251 /* flags for neigh_update() */
252 #define NEIGH_UPDATE_F_OVERRIDE 0x00000001
253 #define NEIGH_UPDATE_F_WEAK_OVERRIDE 0x00000002
254 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER 0x00000004
255 #define NEIGH_UPDATE_F_USE 0x10000000
256 #define NEIGH_UPDATE_F_EXT_LEARNED 0x20000000
257 #define NEIGH_UPDATE_F_ISROUTER 0x40000000
258 #define NEIGH_UPDATE_F_ADMIN 0x80000000
259
260 extern const struct nla_policy nda_policy[];
261
neigh_key_eq32(const struct neighbour * n,const void * pkey)262 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
263 {
264 return *(const u32 *)n->primary_key == *(const u32 *)pkey;
265 }
266
neigh_key_eq128(const struct neighbour * n,const void * pkey)267 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
268 {
269 const u32 *n32 = (const u32 *)n->primary_key;
270 const u32 *p32 = pkey;
271
272 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
273 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
274 }
275
___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)276 static inline struct neighbour *___neigh_lookup_noref(
277 struct neigh_table *tbl,
278 bool (*key_eq)(const struct neighbour *n, const void *pkey),
279 __u32 (*hash)(const void *pkey,
280 const struct net_device *dev,
281 __u32 *hash_rnd),
282 const void *pkey,
283 struct net_device *dev)
284 {
285 struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
286 struct neighbour *n;
287 u32 hash_val;
288
289 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
290 for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
291 n != NULL;
292 n = rcu_dereference_bh(n->next)) {
293 if (n->dev == dev && key_eq(n, pkey))
294 return n;
295 }
296
297 return NULL;
298 }
299
__neigh_lookup_noref(struct neigh_table * tbl,const void * pkey,struct net_device * dev)300 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
301 const void *pkey,
302 struct net_device *dev)
303 {
304 return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
305 }
306
307 void neigh_table_init(int index, struct neigh_table *tbl);
308 int neigh_table_clear(int index, struct neigh_table *tbl);
309 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
310 struct net_device *dev);
311 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
312 struct net_device *dev, bool want_ref);
neigh_create(struct neigh_table * tbl,const void * pkey,struct net_device * dev)313 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
314 const void *pkey,
315 struct net_device *dev)
316 {
317 return __neigh_create(tbl, pkey, dev, true);
318 }
319 void neigh_destroy(struct neighbour *neigh);
320 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
321 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
322 u32 nlmsg_pid);
323 void __neigh_set_probe_once(struct neighbour *neigh);
324 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
325 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
326 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
327 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
328 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
329 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
330 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
331 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
332 u8 *lladdr, void *saddr,
333 struct net_device *dev);
334
335 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
336 struct neigh_table *tbl);
337 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
338
339 static inline
neigh_parms_net(const struct neigh_parms * parms)340 struct net *neigh_parms_net(const struct neigh_parms *parms)
341 {
342 return read_pnet(&parms->net);
343 }
344
345 unsigned long neigh_rand_reach_time(unsigned long base);
346
347 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
348 struct sk_buff *skb);
349 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
350 const void *key, struct net_device *dev,
351 int creat);
352 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
353 const void *key, struct net_device *dev);
354 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
355 struct net_device *dev);
356
pneigh_net(const struct pneigh_entry * pneigh)357 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
358 {
359 return read_pnet(&pneigh->net);
360 }
361
362 void neigh_app_ns(struct neighbour *n);
363 void neigh_for_each(struct neigh_table *tbl,
364 void (*cb)(struct neighbour *, void *), void *cookie);
365 void __neigh_for_each_release(struct neigh_table *tbl,
366 int (*cb)(struct neighbour *));
367 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
368 void pneigh_for_each(struct neigh_table *tbl,
369 void (*cb)(struct pneigh_entry *));
370
371 struct neigh_seq_state {
372 struct seq_net_private p;
373 struct neigh_table *tbl;
374 struct neigh_hash_table *nht;
375 void *(*neigh_sub_iter)(struct neigh_seq_state *state,
376 struct neighbour *n, loff_t *pos);
377 unsigned int bucket;
378 unsigned int flags;
379 #define NEIGH_SEQ_NEIGH_ONLY 0x00000001
380 #define NEIGH_SEQ_IS_PNEIGH 0x00000002
381 #define NEIGH_SEQ_SKIP_NOARP 0x00000004
382 };
383 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
384 unsigned int);
385 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
386 void neigh_seq_stop(struct seq_file *, void *);
387
388 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
389 void __user *buffer, size_t *lenp, loff_t *ppos);
390 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
391 void __user *buffer,
392 size_t *lenp, loff_t *ppos);
393 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
394 void __user *buffer,
395 size_t *lenp, loff_t *ppos);
396
397 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
398 proc_handler *proc_handler);
399 void neigh_sysctl_unregister(struct neigh_parms *p);
400
__neigh_parms_put(struct neigh_parms * parms)401 static inline void __neigh_parms_put(struct neigh_parms *parms)
402 {
403 refcount_dec(&parms->refcnt);
404 }
405
neigh_parms_clone(struct neigh_parms * parms)406 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
407 {
408 refcount_inc(&parms->refcnt);
409 return parms;
410 }
411
412 /*
413 * Neighbour references
414 */
415
neigh_release(struct neighbour * neigh)416 static inline void neigh_release(struct neighbour *neigh)
417 {
418 if (refcount_dec_and_test(&neigh->refcnt))
419 neigh_destroy(neigh);
420 }
421
neigh_clone(struct neighbour * neigh)422 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
423 {
424 if (neigh)
425 refcount_inc(&neigh->refcnt);
426 return neigh;
427 }
428
429 #define neigh_hold(n) refcount_inc(&(n)->refcnt)
430
neigh_event_send(struct neighbour * neigh,struct sk_buff * skb)431 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
432 {
433 unsigned long now = jiffies;
434
435 if (READ_ONCE(neigh->used) != now)
436 WRITE_ONCE(neigh->used, now);
437 if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
438 return __neigh_event_send(neigh, skb);
439 return 0;
440 }
441
442 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
neigh_hh_bridge(struct hh_cache * hh,struct sk_buff * skb)443 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
444 {
445 unsigned int seq, hh_alen;
446
447 do {
448 seq = read_seqbegin(&hh->hh_lock);
449 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
450 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
451 } while (read_seqretry(&hh->hh_lock, seq));
452 return 0;
453 }
454 #endif
455
neigh_hh_output(const struct hh_cache * hh,struct sk_buff * skb)456 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
457 {
458 unsigned int hh_alen = 0;
459 unsigned int seq;
460 unsigned int hh_len;
461
462 do {
463 seq = read_seqbegin(&hh->hh_lock);
464 hh_len = READ_ONCE(hh->hh_len);
465 if (likely(hh_len <= HH_DATA_MOD)) {
466 hh_alen = HH_DATA_MOD;
467
468 /* skb_push() would proceed silently if we have room for
469 * the unaligned size but not for the aligned size:
470 * check headroom explicitly.
471 */
472 if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
473 /* this is inlined by gcc */
474 memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
475 HH_DATA_MOD);
476 }
477 } else {
478 hh_alen = HH_DATA_ALIGN(hh_len);
479
480 if (likely(skb_headroom(skb) >= hh_alen)) {
481 memcpy(skb->data - hh_alen, hh->hh_data,
482 hh_alen);
483 }
484 }
485 } while (read_seqretry(&hh->hh_lock, seq));
486
487 if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
488 kfree_skb(skb);
489 return NET_XMIT_DROP;
490 }
491
492 __skb_push(skb, hh_len);
493 return dev_queue_xmit(skb);
494 }
495
neigh_output(struct neighbour * n,struct sk_buff * skb,bool skip_cache)496 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
497 bool skip_cache)
498 {
499 const struct hh_cache *hh = &n->hh;
500
501 /* n->nud_state and hh->hh_len could be changed under us.
502 * neigh_hh_output() is taking care of the race later.
503 */
504 if (!skip_cache &&
505 (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
506 READ_ONCE(hh->hh_len))
507 return neigh_hh_output(hh, skb);
508
509 return n->output(n, skb);
510 }
511
512 static inline struct neighbour *
__neigh_lookup(struct neigh_table * tbl,const void * pkey,struct net_device * dev,int creat)513 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
514 {
515 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
516
517 if (n || !creat)
518 return n;
519
520 n = neigh_create(tbl, pkey, dev);
521 return IS_ERR(n) ? NULL : n;
522 }
523
524 static inline struct neighbour *
__neigh_lookup_errno(struct neigh_table * tbl,const void * pkey,struct net_device * dev)525 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
526 struct net_device *dev)
527 {
528 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
529
530 if (n)
531 return n;
532
533 return neigh_create(tbl, pkey, dev);
534 }
535
536 struct neighbour_cb {
537 unsigned long sched_next;
538 unsigned int flags;
539 };
540
541 #define LOCALLY_ENQUEUED 0x1
542
543 #define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb)
544
neigh_ha_snapshot(char * dst,const struct neighbour * n,const struct net_device * dev)545 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
546 const struct net_device *dev)
547 {
548 unsigned int seq;
549
550 do {
551 seq = read_seqbegin(&n->ha_lock);
552 memcpy(dst, n->ha, dev->addr_len);
553 } while (read_seqretry(&n->ha_lock, seq));
554 }
555
neigh_update_is_router(struct neighbour * neigh,u32 flags,int * notify)556 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
557 int *notify)
558 {
559 u8 ndm_flags = 0;
560
561 ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
562 if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
563 if (ndm_flags & NTF_ROUTER)
564 neigh->flags |= NTF_ROUTER;
565 else
566 neigh->flags &= ~NTF_ROUTER;
567 *notify = 1;
568 }
569 }
570 #endif
571