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
41struct neighbour;
42
43enum {
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
70struct 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
89static 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
103static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
104{
105 bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
106}
107
108static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
109{
110 bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
111}
112
113struct 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
135struct 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 unsigned int arp_queue_len_bytes;
144 struct sk_buff_head arp_queue;
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 u8 protocol;
153 seqlock_t ha_lock;
154 unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
155 struct hh_cache hh;
156 int (*output)(struct neighbour *, struct sk_buff *);
157 const struct neigh_ops *ops;
158 struct list_head gc_list;
159 struct rcu_head rcu;
160 struct net_device *dev;
161 u8 primary_key[0];
162} __randomize_layout;
163
164struct neigh_ops {
165 int family;
166 void (*solicit)(struct neighbour *, struct sk_buff *);
167 void (*error_report)(struct neighbour *, struct sk_buff *);
168 int (*output)(struct neighbour *, struct sk_buff *);
169 int (*connected_output)(struct neighbour *, struct sk_buff *);
170};
171
172struct pneigh_entry {
173 struct pneigh_entry *next;
174 possible_net_t net;
175 struct net_device *dev;
176 u8 flags;
177 u8 protocol;
178 u8 key[0];
179};
180
181/*
182 * neighbour table manipulation
183 */
184
185#define NEIGH_NUM_HASH_RND 4
186
187struct neigh_hash_table {
188 struct neighbour __rcu **hash_buckets;
189 unsigned int hash_shift;
190 __u32 hash_rnd[NEIGH_NUM_HASH_RND];
191 struct rcu_head rcu;
192};
193
194
195struct neigh_table {
196 int family;
197 unsigned int entry_size;
198 unsigned int key_len;
199 __be16 protocol;
200 __u32 (*hash)(const void *pkey,
201 const struct net_device *dev,
202 __u32 *hash_rnd);
203 bool (*key_eq)(const struct neighbour *, const void *pkey);
204 int (*constructor)(struct neighbour *);
205 int (*pconstructor)(struct pneigh_entry *);
206 void (*pdestructor)(struct pneigh_entry *);
207 void (*proxy_redo)(struct sk_buff *skb);
208 char *id;
209 struct neigh_parms parms;
210 struct list_head parms_list;
211 int gc_interval;
212 int gc_thresh1;
213 int gc_thresh2;
214 int gc_thresh3;
215 unsigned long last_flush;
216 struct delayed_work gc_work;
217 struct timer_list proxy_timer;
218 struct sk_buff_head proxy_queue;
219 atomic_t entries;
220 atomic_t gc_entries;
221 struct list_head gc_list;
222 rwlock_t lock;
223 unsigned long last_rand;
224 struct neigh_statistics __percpu *stats;
225 struct neigh_hash_table __rcu *nht;
226 struct pneigh_entry **phash_buckets;
227};
228
229enum {
230 NEIGH_ARP_TABLE = 0,
231 NEIGH_ND_TABLE = 1,
232 NEIGH_DN_TABLE = 2,
233 NEIGH_NR_TABLES,
234 NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
235};
236
237static inline int neigh_parms_family(struct neigh_parms *p)
238{
239 return p->tbl->family;
240}
241
242#define NEIGH_PRIV_ALIGN sizeof(long long)
243#define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN)
244
245static inline void *neighbour_priv(const struct neighbour *n)
246{
247 return (char *)n + n->tbl->entry_size;
248}
249
250/* flags for neigh_update() */
251#define NEIGH_UPDATE_F_OVERRIDE 0x00000001
252#define NEIGH_UPDATE_F_WEAK_OVERRIDE 0x00000002
253#define NEIGH_UPDATE_F_OVERRIDE_ISROUTER 0x00000004
254#define NEIGH_UPDATE_F_EXT_LEARNED 0x20000000
255#define NEIGH_UPDATE_F_ISROUTER 0x40000000
256#define NEIGH_UPDATE_F_ADMIN 0x80000000
257
258extern const struct nla_policy nda_policy[];
259
260static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
261{
262 return *(const u16 *)n->primary_key == *(const u16 *)pkey;
263}
264
265static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
266{
267 return *(const u32 *)n->primary_key == *(const u32 *)pkey;
268}
269
270static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
271{
272 const u32 *n32 = (const u32 *)n->primary_key;
273 const u32 *p32 = pkey;
274
275 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
276 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
277}
278
279static inline struct neighbour *___neigh_lookup_noref(
280 struct neigh_table *tbl,
281 bool (*key_eq)(const struct neighbour *n, const void *pkey),
282 __u32 (*hash)(const void *pkey,
283 const struct net_device *dev,
284 __u32 *hash_rnd),
285 const void *pkey,
286 struct net_device *dev)
287{
288 struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
289 struct neighbour *n;
290 u32 hash_val;
291
292 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
293 for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
294 n != NULL;
295 n = rcu_dereference_bh(n->next)) {
296 if (n->dev == dev && key_eq(n, pkey))
297 return n;
298 }
299
300 return NULL;
301}
302
303static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
304 const void *pkey,
305 struct net_device *dev)
306{
307 return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
308}
309
310void neigh_table_init(int index, struct neigh_table *tbl);
311int neigh_table_clear(int index, struct neigh_table *tbl);
312struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
313 struct net_device *dev);
314struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
315 const void *pkey);
316struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
317 struct net_device *dev, bool want_ref);
318static inline struct neighbour *neigh_create(struct neigh_table *tbl,
319 const void *pkey,
320 struct net_device *dev)
321{
322 return __neigh_create(tbl, pkey, dev, true);
323}
324void neigh_destroy(struct neighbour *neigh);
325int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
326int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
327 u32 nlmsg_pid);
328void __neigh_set_probe_once(struct neighbour *neigh);
329bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
330void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
331int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
332int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
333int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
334int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
335int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
336struct neighbour *neigh_event_ns(struct neigh_table *tbl,
337 u8 *lladdr, void *saddr,
338 struct net_device *dev);
339
340struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
341 struct neigh_table *tbl);
342void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
343
344static inline
345struct net *neigh_parms_net(const struct neigh_parms *parms)
346{
347 return read_pnet(&parms->net);
348}
349
350unsigned long neigh_rand_reach_time(unsigned long base);
351
352void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
353 struct sk_buff *skb);
354struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
355 const void *key, struct net_device *dev,
356 int creat);
357struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
358 const void *key, struct net_device *dev);
359int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
360 struct net_device *dev);
361
362static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
363{
364 return read_pnet(&pneigh->net);
365}
366
367void neigh_app_ns(struct neighbour *n);
368void neigh_for_each(struct neigh_table *tbl,
369 void (*cb)(struct neighbour *, void *), void *cookie);
370void __neigh_for_each_release(struct neigh_table *tbl,
371 int (*cb)(struct neighbour *));
372int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
373void pneigh_for_each(struct neigh_table *tbl,
374 void (*cb)(struct pneigh_entry *));
375
376struct neigh_seq_state {
377 struct seq_net_private p;
378 struct neigh_table *tbl;
379 struct neigh_hash_table *nht;
380 void *(*neigh_sub_iter)(struct neigh_seq_state *state,
381 struct neighbour *n, loff_t *pos);
382 unsigned int bucket;
383 unsigned int flags;
384#define NEIGH_SEQ_NEIGH_ONLY 0x00000001
385#define NEIGH_SEQ_IS_PNEIGH 0x00000002
386#define NEIGH_SEQ_SKIP_NOARP 0x00000004
387};
388void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
389 unsigned int);
390void *neigh_seq_next(struct seq_file *, void *, loff_t *);
391void neigh_seq_stop(struct seq_file *, void *);
392
393int neigh_proc_dointvec(struct ctl_table *ctl, int write,
394 void __user *buffer, size_t *lenp, loff_t *ppos);
395int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
396 void __user *buffer,
397 size_t *lenp, loff_t *ppos);
398int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
399 void __user *buffer,
400 size_t *lenp, loff_t *ppos);
401
402int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
403 proc_handler *proc_handler);
404void neigh_sysctl_unregister(struct neigh_parms *p);
405
406static inline void __neigh_parms_put(struct neigh_parms *parms)
407{
408 refcount_dec(&parms->refcnt);
409}
410
411static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
412{
413 refcount_inc(&parms->refcnt);
414 return parms;
415}
416
417/*
418 * Neighbour references
419 */
420
421static inline void neigh_release(struct neighbour *neigh)
422{
423 if (refcount_dec_and_test(&neigh->refcnt))
424 neigh_destroy(neigh);
425}
426
427static inline struct neighbour * neigh_clone(struct neighbour *neigh)
428{
429 if (neigh)
430 refcount_inc(&neigh->refcnt);
431 return neigh;
432}
433
434#define neigh_hold(n) refcount_inc(&(n)->refcnt)
435
436static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
437{
438 unsigned long now = jiffies;
439
440 if (neigh->used != now)
441 neigh->used = now;
442 if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
443 return __neigh_event_send(neigh, skb);
444 return 0;
445}
446
447#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
448static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
449{
450 unsigned int seq, hh_alen;
451
452 do {
453 seq = read_seqbegin(&hh->hh_lock);
454 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
455 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
456 } while (read_seqretry(&hh->hh_lock, seq));
457 return 0;
458}
459#endif
460
461static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
462{
463 unsigned int hh_alen = 0;
464 unsigned int seq;
465 unsigned int hh_len;
466
467 do {
468 seq = read_seqbegin(&hh->hh_lock);
469 hh_len = hh->hh_len;
470 if (likely(hh_len <= HH_DATA_MOD)) {
471 hh_alen = HH_DATA_MOD;
472
473 /* skb_push() would proceed silently if we have room for
474 * the unaligned size but not for the aligned size:
475 * check headroom explicitly.
476 */
477 if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
478 /* this is inlined by gcc */
479 memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
480 HH_DATA_MOD);
481 }
482 } else {
483 hh_alen = HH_DATA_ALIGN(hh_len);
484
485 if (likely(skb_headroom(skb) >= hh_alen)) {
486 memcpy(skb->data - hh_alen, hh->hh_data,
487 hh_alen);
488 }
489 }
490 } while (read_seqretry(&hh->hh_lock, seq));
491
492 if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
493 kfree_skb(skb);
494 return NET_XMIT_DROP;
495 }
496
497 __skb_push(skb, hh_len);
498 return dev_queue_xmit(skb);
499}
500
501static inline int neigh_output(struct neighbour *n, struct sk_buff *skb)
502{
503 const struct hh_cache *hh = &n->hh;
504
505 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
506 return neigh_hh_output(hh, skb);
507 else
508 return n->output(n, skb);
509}
510
511static inline struct neighbour *
512__neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
513{
514 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
515
516 if (n || !creat)
517 return n;
518
519 n = neigh_create(tbl, pkey, dev);
520 return IS_ERR(n) ? NULL : n;
521}
522
523static inline struct neighbour *
524__neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
525 struct net_device *dev)
526{
527 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
528
529 if (n)
530 return n;
531
532 return neigh_create(tbl, pkey, dev);
533}
534
535struct neighbour_cb {
536 unsigned long sched_next;
537 unsigned int flags;
538};
539
540#define LOCALLY_ENQUEUED 0x1
541
542#define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb)
543
544static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
545 const struct net_device *dev)
546{
547 unsigned int seq;
548
549 do {
550 seq = read_seqbegin(&n->ha_lock);
551 memcpy(dst, n->ha, dev->addr_len);
552 } while (read_seqretry(&n->ha_lock, seq));
553}
554
555static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
556 int *notify)
557{
558 u8 ndm_flags = 0;
559
560 ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
561 if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
562 if (ndm_flags & NTF_ROUTER)
563 neigh->flags |= NTF_ROUTER;
564 else
565 neigh->flags &= ~NTF_ROUTER;
566 *notify = 1;
567 }
568}
569#endif
570