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#include <net/neighbour_tables.h>
33
34/*
35 * NUD stands for "neighbor unreachability detection"
36 */
37
38#define NUD_IN_TIMER (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
39#define NUD_VALID (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
40#define NUD_CONNECTED (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
41
42struct neighbour;
43
44enum {
45 NEIGH_VAR_MCAST_PROBES,
46 NEIGH_VAR_UCAST_PROBES,
47 NEIGH_VAR_APP_PROBES,
48 NEIGH_VAR_MCAST_REPROBES,
49 NEIGH_VAR_RETRANS_TIME,
50 NEIGH_VAR_BASE_REACHABLE_TIME,
51 NEIGH_VAR_DELAY_PROBE_TIME,
52 NEIGH_VAR_INTERVAL_PROBE_TIME_MS,
53 NEIGH_VAR_GC_STALETIME,
54 NEIGH_VAR_QUEUE_LEN_BYTES,
55 NEIGH_VAR_PROXY_QLEN,
56 NEIGH_VAR_ANYCAST_DELAY,
57 NEIGH_VAR_PROXY_DELAY,
58 NEIGH_VAR_LOCKTIME,
59#define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
60 /* Following are used as a second way to access one of the above */
61 NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
62 NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
63 NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
64 /* Following are used by "default" only */
65 NEIGH_VAR_GC_INTERVAL,
66 NEIGH_VAR_GC_THRESH1,
67 NEIGH_VAR_GC_THRESH2,
68 NEIGH_VAR_GC_THRESH3,
69 NEIGH_VAR_MAX
70};
71
72struct neigh_parms {
73 possible_net_t net;
74 struct net_device *dev;
75 netdevice_tracker dev_tracker;
76 struct list_head list;
77 int (*neigh_setup)(struct neighbour *);
78 struct neigh_table *tbl;
79
80 void *sysctl_table;
81
82 int dead;
83 refcount_t refcnt;
84 struct rcu_head rcu_head;
85
86 int reachable_time;
87 u32 qlen;
88 int data[NEIGH_VAR_DATA_MAX];
89 DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
90};
91
92static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
93{
94 set_bit(nr: index, addr: p->data_state);
95 p->data[index] = val;
96}
97
98#define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
99
100/* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
101 * In other cases, NEIGH_VAR_SET should be used.
102 */
103#define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
104#define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
105
106static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
107{
108 bitmap_fill(dst: p->data_state, NEIGH_VAR_DATA_MAX);
109}
110
111static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
112{
113 bitmap_zero(dst: p->data_state, NEIGH_VAR_DATA_MAX);
114}
115
116struct neigh_statistics {
117 unsigned long allocs; /* number of allocated neighs */
118 unsigned long destroys; /* number of destroyed neighs */
119 unsigned long hash_grows; /* number of hash resizes */
120
121 unsigned long res_failed; /* number of failed resolutions */
122
123 unsigned long lookups; /* number of lookups */
124 unsigned long hits; /* number of hits (among lookups) */
125
126 unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
127 unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
128
129 unsigned long periodic_gc_runs; /* number of periodic GC runs */
130 unsigned long forced_gc_runs; /* number of forced GC runs */
131
132 unsigned long unres_discards; /* number of unresolved drops */
133 unsigned long table_fulls; /* times even gc couldn't help */
134};
135
136#define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
137
138struct neighbour {
139 struct hlist_node hash;
140 struct hlist_node dev_list;
141 struct neigh_table *tbl;
142 struct neigh_parms *parms;
143 unsigned long confirmed;
144 unsigned long updated;
145 rwlock_t lock;
146 refcount_t refcnt;
147 unsigned int arp_queue_len_bytes;
148 struct sk_buff_head arp_queue;
149 struct timer_list timer;
150 unsigned long used;
151 atomic_t probes;
152 u8 nud_state;
153 u8 type;
154 u8 dead;
155 u8 protocol;
156 u32 flags;
157 seqlock_t ha_lock;
158 unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
159 struct hh_cache hh;
160 int (*output)(struct neighbour *, struct sk_buff *);
161 const struct neigh_ops *ops;
162 struct list_head gc_list;
163 struct list_head managed_list;
164 struct rcu_head rcu;
165 struct net_device *dev;
166 netdevice_tracker dev_tracker;
167 u8 primary_key[];
168} __randomize_layout;
169
170struct neigh_ops {
171 int family;
172 void (*solicit)(struct neighbour *, struct sk_buff *);
173 void (*error_report)(struct neighbour *, struct sk_buff *);
174 int (*output)(struct neighbour *, struct sk_buff *);
175 int (*connected_output)(struct neighbour *, struct sk_buff *);
176};
177
178struct pneigh_entry {
179 struct pneigh_entry *next;
180 possible_net_t net;
181 struct net_device *dev;
182 netdevice_tracker dev_tracker;
183 u32 flags;
184 u8 protocol;
185 u32 key[];
186};
187
188/*
189 * neighbour table manipulation
190 */
191
192#define NEIGH_NUM_HASH_RND 4
193
194struct neigh_hash_table {
195 struct hlist_head *hash_heads;
196 unsigned int hash_shift;
197 __u32 hash_rnd[NEIGH_NUM_HASH_RND];
198 struct rcu_head rcu;
199};
200
201
202struct neigh_table {
203 int family;
204 unsigned int entry_size;
205 unsigned int key_len;
206 __be16 protocol;
207 __u32 (*hash)(const void *pkey,
208 const struct net_device *dev,
209 __u32 *hash_rnd);
210 bool (*key_eq)(const struct neighbour *, const void *pkey);
211 int (*constructor)(struct neighbour *);
212 int (*pconstructor)(struct pneigh_entry *);
213 void (*pdestructor)(struct pneigh_entry *);
214 void (*proxy_redo)(struct sk_buff *skb);
215 int (*is_multicast)(const void *pkey);
216 bool (*allow_add)(const struct net_device *dev,
217 struct netlink_ext_ack *extack);
218 char *id;
219 struct neigh_parms parms;
220 struct list_head parms_list;
221 int gc_interval;
222 int gc_thresh1;
223 int gc_thresh2;
224 int gc_thresh3;
225 unsigned long last_flush;
226 struct delayed_work gc_work;
227 struct delayed_work managed_work;
228 struct timer_list proxy_timer;
229 struct sk_buff_head proxy_queue;
230 atomic_t entries;
231 atomic_t gc_entries;
232 struct list_head gc_list;
233 struct list_head managed_list;
234 rwlock_t lock;
235 unsigned long last_rand;
236 struct neigh_statistics __percpu *stats;
237 struct neigh_hash_table __rcu *nht;
238 struct pneigh_entry **phash_buckets;
239};
240
241static inline int neigh_parms_family(struct neigh_parms *p)
242{
243 return p->tbl->family;
244}
245
246#define NEIGH_PRIV_ALIGN sizeof(long long)
247#define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN)
248
249static inline void *neighbour_priv(const struct neighbour *n)
250{
251 return (char *)n + n->tbl->entry_size;
252}
253
254/* flags for neigh_update() */
255#define NEIGH_UPDATE_F_OVERRIDE BIT(0)
256#define NEIGH_UPDATE_F_WEAK_OVERRIDE BIT(1)
257#define NEIGH_UPDATE_F_OVERRIDE_ISROUTER BIT(2)
258#define NEIGH_UPDATE_F_USE BIT(3)
259#define NEIGH_UPDATE_F_MANAGED BIT(4)
260#define NEIGH_UPDATE_F_EXT_LEARNED BIT(5)
261#define NEIGH_UPDATE_F_ISROUTER BIT(6)
262#define NEIGH_UPDATE_F_ADMIN BIT(7)
263
264/* In-kernel representation for NDA_FLAGS_EXT flags: */
265#define NTF_OLD_MASK 0xff
266#define NTF_EXT_SHIFT 8
267#define NTF_EXT_MASK (NTF_EXT_MANAGED)
268
269#define NTF_MANAGED (NTF_EXT_MANAGED << NTF_EXT_SHIFT)
270
271extern const struct nla_policy nda_policy[];
272
273#define neigh_for_each_in_bucket(pos, head) hlist_for_each_entry(pos, head, hash)
274#define neigh_for_each_in_bucket_rcu(pos, head) \
275 hlist_for_each_entry_rcu(pos, head, hash)
276#define neigh_for_each_in_bucket_safe(pos, tmp, head) \
277 hlist_for_each_entry_safe(pos, tmp, head, hash)
278
279static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
280{
281 return *(const u32 *)n->primary_key == *(const u32 *)pkey;
282}
283
284static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
285{
286 const u32 *n32 = (const u32 *)n->primary_key;
287 const u32 *p32 = pkey;
288
289 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
290 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
291}
292
293static inline struct neighbour *___neigh_lookup_noref(
294 struct neigh_table *tbl,
295 bool (*key_eq)(const struct neighbour *n, const void *pkey),
296 __u32 (*hash)(const void *pkey,
297 const struct net_device *dev,
298 __u32 *hash_rnd),
299 const void *pkey,
300 struct net_device *dev)
301{
302 struct neigh_hash_table *nht = rcu_dereference(tbl->nht);
303 struct neighbour *n;
304 u32 hash_val;
305
306 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
307 neigh_for_each_in_bucket_rcu(n, &nht->hash_heads[hash_val])
308 if (n->dev == dev && key_eq(n, pkey))
309 return n;
310
311 return NULL;
312}
313
314static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
315 const void *pkey,
316 struct net_device *dev)
317{
318 return ___neigh_lookup_noref(tbl, key_eq: tbl->key_eq, hash: tbl->hash, pkey, dev);
319}
320
321static inline void neigh_confirm(struct neighbour *n)
322{
323 if (n) {
324 unsigned long now = jiffies;
325
326 /* avoid dirtying neighbour */
327 if (READ_ONCE(n->confirmed) != now)
328 WRITE_ONCE(n->confirmed, now);
329 }
330}
331
332void neigh_table_init(int index, struct neigh_table *tbl);
333int neigh_table_clear(int index, struct neigh_table *tbl);
334struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
335 struct net_device *dev);
336struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
337 struct net_device *dev, bool want_ref);
338static inline struct neighbour *neigh_create(struct neigh_table *tbl,
339 const void *pkey,
340 struct net_device *dev)
341{
342 return __neigh_create(tbl, pkey, dev, want_ref: true);
343}
344void neigh_destroy(struct neighbour *neigh);
345int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
346 const bool immediate_ok);
347int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
348 u32 nlmsg_pid);
349void __neigh_set_probe_once(struct neighbour *neigh);
350bool neigh_remove_one(struct neighbour *ndel);
351void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
352int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
353int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
354int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
355int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
356int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
357struct neighbour *neigh_event_ns(struct neigh_table *tbl,
358 u8 *lladdr, void *saddr,
359 struct net_device *dev);
360
361struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
362 struct neigh_table *tbl);
363void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
364
365static inline
366struct net *neigh_parms_net(const struct neigh_parms *parms)
367{
368 return read_pnet(pnet: &parms->net);
369}
370
371unsigned long neigh_rand_reach_time(unsigned long base);
372
373void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
374 struct sk_buff *skb);
375struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
376 const void *key, struct net_device *dev,
377 int creat);
378struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
379 const void *key, struct net_device *dev);
380int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
381 struct net_device *dev);
382
383static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
384{
385 return read_pnet(pnet: &pneigh->net);
386}
387
388void neigh_app_ns(struct neighbour *n);
389void neigh_for_each(struct neigh_table *tbl,
390 void (*cb)(struct neighbour *, void *), void *cookie);
391void __neigh_for_each_release(struct neigh_table *tbl,
392 int (*cb)(struct neighbour *));
393int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
394
395struct neigh_seq_state {
396 struct seq_net_private p;
397 struct neigh_table *tbl;
398 struct neigh_hash_table *nht;
399 void *(*neigh_sub_iter)(struct neigh_seq_state *state,
400 struct neighbour *n, loff_t *pos);
401 unsigned int bucket;
402 unsigned int flags;
403#define NEIGH_SEQ_NEIGH_ONLY 0x00000001
404#define NEIGH_SEQ_IS_PNEIGH 0x00000002
405#define NEIGH_SEQ_SKIP_NOARP 0x00000004
406};
407void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
408 unsigned int);
409void *neigh_seq_next(struct seq_file *, void *, loff_t *);
410void neigh_seq_stop(struct seq_file *, void *);
411
412int neigh_proc_dointvec(const struct ctl_table *ctl, int write,
413 void *buffer, size_t *lenp, loff_t *ppos);
414int neigh_proc_dointvec_jiffies(const struct ctl_table *ctl, int write,
415 void *buffer,
416 size_t *lenp, loff_t *ppos);
417int neigh_proc_dointvec_ms_jiffies(const struct ctl_table *ctl, int write,
418 void *buffer, size_t *lenp, loff_t *ppos);
419
420int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
421 proc_handler *proc_handler);
422void neigh_sysctl_unregister(struct neigh_parms *p);
423
424static inline void __neigh_parms_put(struct neigh_parms *parms)
425{
426 refcount_dec(r: &parms->refcnt);
427}
428
429static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
430{
431 refcount_inc(r: &parms->refcnt);
432 return parms;
433}
434
435/*
436 * Neighbour references
437 */
438
439static inline void neigh_release(struct neighbour *neigh)
440{
441 if (refcount_dec_and_test(r: &neigh->refcnt))
442 neigh_destroy(neigh);
443}
444
445static inline struct neighbour * neigh_clone(struct neighbour *neigh)
446{
447 if (neigh)
448 refcount_inc(r: &neigh->refcnt);
449 return neigh;
450}
451
452#define neigh_hold(n) refcount_inc(&(n)->refcnt)
453
454static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
455 struct sk_buff *skb,
456 const bool immediate_ok)
457{
458 unsigned long now = jiffies;
459
460 if (READ_ONCE(neigh->used) != now)
461 WRITE_ONCE(neigh->used, now);
462 if (!(READ_ONCE(neigh->nud_state) & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
463 return __neigh_event_send(neigh, skb, immediate_ok);
464 return 0;
465}
466
467static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
468{
469 return neigh_event_send_probe(neigh, skb, immediate_ok: true);
470}
471
472#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
473static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
474{
475 unsigned int seq, hh_alen;
476
477 do {
478 seq = read_seqbegin(sl: &hh->hh_lock);
479 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
480 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
481 } while (read_seqretry(sl: &hh->hh_lock, start: seq));
482 return 0;
483}
484#endif
485
486static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
487{
488 unsigned int hh_alen = 0;
489 unsigned int seq;
490 unsigned int hh_len;
491
492 do {
493 seq = read_seqbegin(sl: &hh->hh_lock);
494 hh_len = READ_ONCE(hh->hh_len);
495 if (likely(hh_len <= HH_DATA_MOD)) {
496 hh_alen = HH_DATA_MOD;
497
498 /* skb_push() would proceed silently if we have room for
499 * the unaligned size but not for the aligned size:
500 * check headroom explicitly.
501 */
502 if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
503 /* this is inlined by gcc */
504 memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
505 HH_DATA_MOD);
506 }
507 } else {
508 hh_alen = HH_DATA_ALIGN(hh_len);
509
510 if (likely(skb_headroom(skb) >= hh_alen)) {
511 memcpy(skb->data - hh_alen, hh->hh_data,
512 hh_alen);
513 }
514 }
515 } while (read_seqretry(sl: &hh->hh_lock, start: seq));
516
517 if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
518 kfree_skb(skb);
519 return NET_XMIT_DROP;
520 }
521
522 __skb_push(skb, len: hh_len);
523 return dev_queue_xmit(skb);
524}
525
526static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
527 bool skip_cache)
528{
529 const struct hh_cache *hh = &n->hh;
530
531 /* n->nud_state and hh->hh_len could be changed under us.
532 * neigh_hh_output() is taking care of the race later.
533 */
534 if (!skip_cache &&
535 (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
536 READ_ONCE(hh->hh_len))
537 return neigh_hh_output(hh, skb);
538
539 return READ_ONCE(n->output)(n, skb);
540}
541
542static inline struct neighbour *
543__neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
544{
545 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
546
547 if (n || !creat)
548 return n;
549
550 n = neigh_create(tbl, pkey, dev);
551 return IS_ERR(ptr: n) ? NULL : n;
552}
553
554static inline struct neighbour *
555__neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
556 struct net_device *dev)
557{
558 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
559
560 if (n)
561 return n;
562
563 return neigh_create(tbl, pkey, dev);
564}
565
566struct neighbour_cb {
567 unsigned long sched_next;
568 unsigned int flags;
569};
570
571#define LOCALLY_ENQUEUED 0x1
572
573#define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb)
574
575static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
576 const struct net_device *dev)
577{
578 unsigned int seq;
579
580 do {
581 seq = read_seqbegin(sl: &n->ha_lock);
582 memcpy(dst, n->ha, dev->addr_len);
583 } while (read_seqretry(sl: &n->ha_lock, start: seq));
584}
585
586static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
587 int *notify)
588{
589 u8 ndm_flags = 0;
590
591 ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
592 if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
593 if (ndm_flags & NTF_ROUTER)
594 neigh->flags |= NTF_ROUTER;
595 else
596 neigh->flags &= ~NTF_ROUTER;
597 *notify = 1;
598 }
599}
600#endif
601

source code of linux/include/net/neighbour.h