1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _NET_NEIGHBOUR_H
3 #define _NET_NEIGHBOUR_H
5 #include <linux/neighbour.h>
8 * Generic neighbour manipulation
11 * Pedro Roque <roque@di.fc.ul.pt>
12 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
16 * Harald Welte: <laforge@gnumonks.org>
17 * - Add neighbour cache statistics like rtstat
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>
28 #include <linux/err.h>
29 #include <linux/sysctl.h>
30 #include <linux/workqueue.h>
31 #include <net/rtnetlink.h>
34 * NUD stands for "neighbor unreachability detection"
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)
44 NEIGH_VAR_MCAST_PROBES,
45 NEIGH_VAR_UCAST_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,
54 NEIGH_VAR_ANYCAST_DELAY,
55 NEIGH_VAR_PROXY_DELAY,
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,
72 struct net_device *dev;
73 netdevice_tracker dev_tracker;
74 struct list_head list;
75 int (*neigh_setup)(struct neighbour *);
76 struct neigh_table *tbl;
82 struct rcu_head rcu_head;
85 int data[NEIGH_VAR_DATA_MAX];
86 DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
89 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
91 set_bit(index, p->data_state);
95 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
97 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
98 * In other cases, NEIGH_VAR_SET should be used.
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)
103 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
105 bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
108 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
110 bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
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 */
118 unsigned long res_failed; /* number of failed resolutions */
120 unsigned long lookups; /* number of lookups */
121 unsigned long hits; /* number of hits (among lookups) */
123 unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
124 unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
126 unsigned long periodic_gc_runs; /* number of periodic GC runs */
127 unsigned long forced_gc_runs; /* number of forced GC runs */
129 unsigned long unres_discards; /* number of unresolved drops */
130 unsigned long table_fulls; /* times even gc couldn't help */
133 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
136 struct neighbour __rcu *next;
137 struct neigh_table *tbl;
138 struct neigh_parms *parms;
139 unsigned long confirmed;
140 unsigned long updated;
143 unsigned int arp_queue_len_bytes;
144 struct sk_buff_head arp_queue;
145 struct timer_list timer;
154 unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
156 int (*output)(struct neighbour *, struct sk_buff *);
157 const struct neigh_ops *ops;
158 struct list_head gc_list;
159 struct list_head managed_list;
161 struct net_device *dev;
162 netdevice_tracker dev_tracker;
164 } __randomize_layout;
168 void (*solicit)(struct neighbour *, struct sk_buff *);
169 void (*error_report)(struct neighbour *, struct sk_buff *);
170 int (*output)(struct neighbour *, struct sk_buff *);
171 int (*connected_output)(struct neighbour *, struct sk_buff *);
174 struct pneigh_entry {
175 struct pneigh_entry *next;
177 struct net_device *dev;
178 netdevice_tracker dev_tracker;
185 * neighbour table manipulation
188 #define NEIGH_NUM_HASH_RND 4
190 struct neigh_hash_table {
191 struct neighbour __rcu **hash_buckets;
192 unsigned int hash_shift;
193 __u32 hash_rnd[NEIGH_NUM_HASH_RND];
200 unsigned int entry_size;
201 unsigned int key_len;
203 __u32 (*hash)(const void *pkey,
204 const struct net_device *dev,
206 bool (*key_eq)(const struct neighbour *, const void *pkey);
207 int (*constructor)(struct neighbour *);
208 int (*pconstructor)(struct pneigh_entry *);
209 void (*pdestructor)(struct pneigh_entry *);
210 void (*proxy_redo)(struct sk_buff *skb);
211 int (*is_multicast)(const void *pkey);
212 bool (*allow_add)(const struct net_device *dev,
213 struct netlink_ext_ack *extack);
215 struct neigh_parms parms;
216 struct list_head parms_list;
221 unsigned long last_flush;
222 struct delayed_work gc_work;
223 struct delayed_work managed_work;
224 struct timer_list proxy_timer;
225 struct sk_buff_head proxy_queue;
228 struct list_head gc_list;
229 struct list_head managed_list;
231 unsigned long last_rand;
232 struct neigh_statistics __percpu *stats;
233 struct neigh_hash_table __rcu *nht;
234 struct pneigh_entry **phash_buckets;
242 NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
245 static inline int neigh_parms_family(struct neigh_parms *p)
247 return p->tbl->family;
250 #define NEIGH_PRIV_ALIGN sizeof(long long)
251 #define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN)
253 static inline void *neighbour_priv(const struct neighbour *n)
255 return (char *)n + n->tbl->entry_size;
258 /* flags for neigh_update() */
259 #define NEIGH_UPDATE_F_OVERRIDE BIT(0)
260 #define NEIGH_UPDATE_F_WEAK_OVERRIDE BIT(1)
261 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER BIT(2)
262 #define NEIGH_UPDATE_F_USE BIT(3)
263 #define NEIGH_UPDATE_F_MANAGED BIT(4)
264 #define NEIGH_UPDATE_F_EXT_LEARNED BIT(5)
265 #define NEIGH_UPDATE_F_ISROUTER BIT(6)
266 #define NEIGH_UPDATE_F_ADMIN BIT(7)
268 /* In-kernel representation for NDA_FLAGS_EXT flags: */
269 #define NTF_OLD_MASK 0xff
270 #define NTF_EXT_SHIFT 8
271 #define NTF_EXT_MASK (NTF_EXT_MANAGED)
273 #define NTF_MANAGED (NTF_EXT_MANAGED << NTF_EXT_SHIFT)
275 extern const struct nla_policy nda_policy[];
277 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
279 return *(const u16 *)n->primary_key == *(const u16 *)pkey;
282 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
284 return *(const u32 *)n->primary_key == *(const u32 *)pkey;
287 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
289 const u32 *n32 = (const u32 *)n->primary_key;
290 const u32 *p32 = pkey;
292 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
293 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
296 static inline struct neighbour *___neigh_lookup_noref(
297 struct neigh_table *tbl,
298 bool (*key_eq)(const struct neighbour *n, const void *pkey),
299 __u32 (*hash)(const void *pkey,
300 const struct net_device *dev,
303 struct net_device *dev)
305 struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
309 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
310 for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
312 n = rcu_dereference_bh(n->next)) {
313 if (n->dev == dev && key_eq(n, pkey))
320 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
322 struct net_device *dev)
324 return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
327 static inline void neigh_confirm(struct neighbour *n)
330 unsigned long now = jiffies;
332 /* avoid dirtying neighbour */
333 if (READ_ONCE(n->confirmed) != now)
334 WRITE_ONCE(n->confirmed, now);
338 void neigh_table_init(int index, struct neigh_table *tbl);
339 int neigh_table_clear(int index, struct neigh_table *tbl);
340 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
341 struct net_device *dev);
342 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
344 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
345 struct net_device *dev, bool want_ref);
346 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
348 struct net_device *dev)
350 return __neigh_create(tbl, pkey, dev, true);
352 void neigh_destroy(struct neighbour *neigh);
353 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
354 const bool immediate_ok);
355 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
357 void __neigh_set_probe_once(struct neighbour *neigh);
358 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
359 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
360 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
361 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
362 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
363 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
364 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
365 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
366 u8 *lladdr, void *saddr,
367 struct net_device *dev);
369 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
370 struct neigh_table *tbl);
371 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
374 struct net *neigh_parms_net(const struct neigh_parms *parms)
376 return read_pnet(&parms->net);
379 unsigned long neigh_rand_reach_time(unsigned long base);
381 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
382 struct sk_buff *skb);
383 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
384 const void *key, struct net_device *dev,
386 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
387 const void *key, struct net_device *dev);
388 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
389 struct net_device *dev);
391 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
393 return read_pnet(&pneigh->net);
396 void neigh_app_ns(struct neighbour *n);
397 void neigh_for_each(struct neigh_table *tbl,
398 void (*cb)(struct neighbour *, void *), void *cookie);
399 void __neigh_for_each_release(struct neigh_table *tbl,
400 int (*cb)(struct neighbour *));
401 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
402 void pneigh_for_each(struct neigh_table *tbl,
403 void (*cb)(struct pneigh_entry *));
405 struct neigh_seq_state {
406 struct seq_net_private p;
407 struct neigh_table *tbl;
408 struct neigh_hash_table *nht;
409 void *(*neigh_sub_iter)(struct neigh_seq_state *state,
410 struct neighbour *n, loff_t *pos);
413 #define NEIGH_SEQ_NEIGH_ONLY 0x00000001
414 #define NEIGH_SEQ_IS_PNEIGH 0x00000002
415 #define NEIGH_SEQ_SKIP_NOARP 0x00000004
417 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
419 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
420 void neigh_seq_stop(struct seq_file *, void *);
422 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
423 void *buffer, size_t *lenp, loff_t *ppos);
424 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
426 size_t *lenp, loff_t *ppos);
427 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
428 void *buffer, size_t *lenp, loff_t *ppos);
430 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
431 proc_handler *proc_handler);
432 void neigh_sysctl_unregister(struct neigh_parms *p);
434 static inline void __neigh_parms_put(struct neigh_parms *parms)
436 refcount_dec(&parms->refcnt);
439 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
441 refcount_inc(&parms->refcnt);
446 * Neighbour references
449 static inline void neigh_release(struct neighbour *neigh)
451 if (refcount_dec_and_test(&neigh->refcnt))
452 neigh_destroy(neigh);
455 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
458 refcount_inc(&neigh->refcnt);
462 #define neigh_hold(n) refcount_inc(&(n)->refcnt)
464 static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
466 const bool immediate_ok)
468 unsigned long now = jiffies;
470 if (READ_ONCE(neigh->used) != now)
471 WRITE_ONCE(neigh->used, now);
472 if (!(neigh->nud_state & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
473 return __neigh_event_send(neigh, skb, immediate_ok);
477 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
479 return neigh_event_send_probe(neigh, skb, true);
482 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
483 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
485 unsigned int seq, hh_alen;
488 seq = read_seqbegin(&hh->hh_lock);
489 hh_alen = HH_DATA_ALIGN(ETH_HLEN);
490 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
491 } while (read_seqretry(&hh->hh_lock, seq));
496 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
498 unsigned int hh_alen = 0;
503 seq = read_seqbegin(&hh->hh_lock);
504 hh_len = READ_ONCE(hh->hh_len);
505 if (likely(hh_len <= HH_DATA_MOD)) {
506 hh_alen = HH_DATA_MOD;
508 /* skb_push() would proceed silently if we have room for
509 * the unaligned size but not for the aligned size:
510 * check headroom explicitly.
512 if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
513 /* this is inlined by gcc */
514 memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
518 hh_alen = HH_DATA_ALIGN(hh_len);
520 if (likely(skb_headroom(skb) >= hh_alen)) {
521 memcpy(skb->data - hh_alen, hh->hh_data,
525 } while (read_seqretry(&hh->hh_lock, seq));
527 if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
529 return NET_XMIT_DROP;
532 __skb_push(skb, hh_len);
533 return dev_queue_xmit(skb);
536 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
539 const struct hh_cache *hh = &n->hh;
541 /* n->nud_state and hh->hh_len could be changed under us.
542 * neigh_hh_output() is taking care of the race later.
545 (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
546 READ_ONCE(hh->hh_len))
547 return neigh_hh_output(hh, skb);
549 return n->output(n, skb);
552 static inline struct neighbour *
553 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
555 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
560 n = neigh_create(tbl, pkey, dev);
561 return IS_ERR(n) ? NULL : n;
564 static inline struct neighbour *
565 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
566 struct net_device *dev)
568 struct neighbour *n = neigh_lookup(tbl, pkey, dev);
573 return neigh_create(tbl, pkey, dev);
576 struct neighbour_cb {
577 unsigned long sched_next;
581 #define LOCALLY_ENQUEUED 0x1
583 #define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb)
585 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
586 const struct net_device *dev)
591 seq = read_seqbegin(&n->ha_lock);
592 memcpy(dst, n->ha, dev->addr_len);
593 } while (read_seqretry(&n->ha_lock, seq));
596 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
601 ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
602 if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
603 if (ndm_flags & NTF_ROUTER)
604 neigh->flags |= NTF_ROUTER;
606 neigh->flags &= ~NTF_ROUTER;