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	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
88static 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
102static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
103{
104	bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
105}
106
107static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
108{
109	bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
110}
111
112struct 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
134struct 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
163struct 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
171struct pneigh_entry {
172	struct pneigh_entry	*next;
173	possible_net_t		net;
174	struct net_device	*dev;
175	u8			flags;
176	u8			protocol;
177	u32			key[];
178};
179
180/*
181 *	neighbour table manipulation
182 */
183
184#define NEIGH_NUM_HASH_RND	4
185
186struct 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
194struct 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	int			(*is_multicast)(const void *pkey);
208	bool			(*allow_add)(const struct net_device *dev,
209					     struct netlink_ext_ack *extack);
210	char			*id;
211	struct neigh_parms	parms;
212	struct list_head	parms_list;
213	int			gc_interval;
214	int			gc_thresh1;
215	int			gc_thresh2;
216	int			gc_thresh3;
217	unsigned long		last_flush;
218	struct delayed_work	gc_work;
219	struct timer_list 	proxy_timer;
220	struct sk_buff_head	proxy_queue;
221	atomic_t		entries;
222	atomic_t		gc_entries;
223	struct list_head	gc_list;
224	rwlock_t		lock;
225	unsigned long		last_rand;
226	struct neigh_statistics	__percpu *stats;
227	struct neigh_hash_table __rcu *nht;
228	struct pneigh_entry	**phash_buckets;
229};
230
231enum {
232	NEIGH_ARP_TABLE = 0,
233	NEIGH_ND_TABLE = 1,
234	NEIGH_DN_TABLE = 2,
235#ifdef CONFIG_NEWIP
236	NEIGH_NND_TABLE = 3,	/* NIP */
237#endif
238	NEIGH_NR_TABLES,
239	NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
240};
241
242static inline int neigh_parms_family(struct neigh_parms *p)
243{
244	return p->tbl->family;
245}
246
247#define NEIGH_PRIV_ALIGN	sizeof(long long)
248#define NEIGH_ENTRY_SIZE(size)	ALIGN((size), NEIGH_PRIV_ALIGN)
249
250static inline void *neighbour_priv(const struct neighbour *n)
251{
252	return (char *)n + n->tbl->entry_size;
253}
254
255/* flags for neigh_update() */
256#define NEIGH_UPDATE_F_OVERRIDE			0x00000001
257#define NEIGH_UPDATE_F_WEAK_OVERRIDE		0x00000002
258#define NEIGH_UPDATE_F_OVERRIDE_ISROUTER	0x00000004
259#define NEIGH_UPDATE_F_USE			0x10000000
260#define NEIGH_UPDATE_F_EXT_LEARNED		0x20000000
261#define NEIGH_UPDATE_F_ISROUTER			0x40000000
262#define NEIGH_UPDATE_F_ADMIN			0x80000000
263
264extern const struct nla_policy nda_policy[];
265
266static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
267{
268	return *(const u32 *)n->primary_key == *(const u32 *)pkey;
269}
270
271static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
272{
273	const u32 *n32 = (const u32 *)n->primary_key;
274	const u32 *p32 = pkey;
275
276	return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
277		(n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
278}
279
280static inline struct neighbour *___neigh_lookup_noref(
281	struct neigh_table *tbl,
282	bool (*key_eq)(const struct neighbour *n, const void *pkey),
283	__u32 (*hash)(const void *pkey,
284		      const struct net_device *dev,
285		      __u32 *hash_rnd),
286	const void *pkey,
287	struct net_device *dev)
288{
289	struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
290	struct neighbour *n;
291	u32 hash_val;
292
293	hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
294	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
295	     n != NULL;
296	     n = rcu_dereference_bh(n->next)) {
297		if (n->dev == dev && key_eq(n, pkey))
298			return n;
299	}
300
301	return NULL;
302}
303
304static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
305						     const void *pkey,
306						     struct net_device *dev)
307{
308	return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
309}
310
311void neigh_table_init(int index, struct neigh_table *tbl);
312int neigh_table_clear(int index, struct neigh_table *tbl);
313struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
314			       struct net_device *dev);
315struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
316				 struct net_device *dev, bool want_ref);
317static inline struct neighbour *neigh_create(struct neigh_table *tbl,
318					     const void *pkey,
319					     struct net_device *dev)
320{
321	return __neigh_create(tbl, pkey, dev, true);
322}
323void neigh_destroy(struct neighbour *neigh);
324int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
325int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
326		 u32 nlmsg_pid);
327void __neigh_set_probe_once(struct neighbour *neigh);
328bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
329void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
330int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
331int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
332int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
333int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
334int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
335struct neighbour *neigh_event_ns(struct neigh_table *tbl,
336						u8 *lladdr, void *saddr,
337						struct net_device *dev);
338
339struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
340				      struct neigh_table *tbl);
341void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
342
343static inline
344struct net *neigh_parms_net(const struct neigh_parms *parms)
345{
346	return read_pnet(&parms->net);
347}
348
349unsigned long neigh_rand_reach_time(unsigned long base);
350
351void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
352		    struct sk_buff *skb);
353struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
354				   const void *key, struct net_device *dev,
355				   int creat);
356struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
357				     const void *key, struct net_device *dev);
358int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
359		  struct net_device *dev);
360
361static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
362{
363	return read_pnet(&pneigh->net);
364}
365
366void neigh_app_ns(struct neighbour *n);
367void neigh_for_each(struct neigh_table *tbl,
368		    void (*cb)(struct neighbour *, void *), void *cookie);
369void __neigh_for_each_release(struct neigh_table *tbl,
370			      int (*cb)(struct neighbour *));
371int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
372void pneigh_for_each(struct neigh_table *tbl,
373		     void (*cb)(struct pneigh_entry *));
374
375struct neigh_seq_state {
376	struct seq_net_private p;
377	struct neigh_table *tbl;
378	struct neigh_hash_table *nht;
379	void *(*neigh_sub_iter)(struct neigh_seq_state *state,
380				struct neighbour *n, loff_t *pos);
381	unsigned int bucket;
382	unsigned int flags;
383#define NEIGH_SEQ_NEIGH_ONLY	0x00000001
384#define NEIGH_SEQ_IS_PNEIGH	0x00000002
385#define NEIGH_SEQ_SKIP_NOARP	0x00000004
386};
387void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
388		      unsigned int);
389void *neigh_seq_next(struct seq_file *, void *, loff_t *);
390void neigh_seq_stop(struct seq_file *, void *);
391
392int neigh_proc_dointvec(struct ctl_table *ctl, int write,
393			void *buffer, size_t *lenp, loff_t *ppos);
394int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
395				void *buffer,
396				size_t *lenp, loff_t *ppos);
397int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
398				   void *buffer, size_t *lenp, loff_t *ppos);
399
400int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
401			  proc_handler *proc_handler);
402void neigh_sysctl_unregister(struct neigh_parms *p);
403
404static inline void __neigh_parms_put(struct neigh_parms *parms)
405{
406	refcount_dec(&parms->refcnt);
407}
408
409static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
410{
411	refcount_inc(&parms->refcnt);
412	return parms;
413}
414
415/*
416 *	Neighbour references
417 */
418
419static inline void neigh_release(struct neighbour *neigh)
420{
421	if (refcount_dec_and_test(&neigh->refcnt))
422		neigh_destroy(neigh);
423}
424
425static inline struct neighbour * neigh_clone(struct neighbour *neigh)
426{
427	if (neigh)
428		refcount_inc(&neigh->refcnt);
429	return neigh;
430}
431
432#define neigh_hold(n)	refcount_inc(&(n)->refcnt)
433
434static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
435{
436	unsigned long now = jiffies;
437
438	if (READ_ONCE(neigh->used) != now)
439		WRITE_ONCE(neigh->used, now);
440	if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
441		return __neigh_event_send(neigh, skb);
442	return 0;
443}
444
445#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
446static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
447{
448	unsigned int seq, hh_alen;
449
450	do {
451		seq = read_seqbegin(&hh->hh_lock);
452		hh_alen = HH_DATA_ALIGN(ETH_HLEN);
453		memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
454	} while (read_seqretry(&hh->hh_lock, seq));
455	return 0;
456}
457#endif
458
459static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
460{
461	unsigned int hh_alen = 0;
462	unsigned int seq;
463	unsigned int hh_len;
464
465	do {
466		seq = read_seqbegin(&hh->hh_lock);
467		hh_len = READ_ONCE(hh->hh_len);
468		if (likely(hh_len <= HH_DATA_MOD)) {
469			hh_alen = HH_DATA_MOD;
470
471			/* skb_push() would proceed silently if we have room for
472			 * the unaligned size but not for the aligned size:
473			 * check headroom explicitly.
474			 */
475			if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
476				/* this is inlined by gcc */
477				memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
478				       HH_DATA_MOD);
479			}
480		} else {
481			hh_alen = HH_DATA_ALIGN(hh_len);
482
483			if (likely(skb_headroom(skb) >= hh_alen)) {
484				memcpy(skb->data - hh_alen, hh->hh_data,
485				       hh_alen);
486			}
487		}
488	} while (read_seqretry(&hh->hh_lock, seq));
489
490	if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
491		kfree_skb(skb);
492		return NET_XMIT_DROP;
493	}
494
495	__skb_push(skb, hh_len);
496	return dev_queue_xmit(skb);
497}
498
499static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
500			       bool skip_cache)
501{
502	const struct hh_cache *hh = &n->hh;
503
504	/* n->nud_state and hh->hh_len could be changed under us.
505	 * neigh_hh_output() is taking care of the race later.
506	 */
507	if (!skip_cache &&
508	    (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
509	    READ_ONCE(hh->hh_len))
510		return neigh_hh_output(hh, skb);
511
512	return n->output(n, skb);
513}
514
515static inline struct neighbour *
516__neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
517{
518	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
519
520	if (n || !creat)
521		return n;
522
523	n = neigh_create(tbl, pkey, dev);
524	return IS_ERR(n) ? NULL : n;
525}
526
527static inline struct neighbour *
528__neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
529  struct net_device *dev)
530{
531	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
532
533	if (n)
534		return n;
535
536	return neigh_create(tbl, pkey, dev);
537}
538
539struct neighbour_cb {
540	unsigned long sched_next;
541	unsigned int flags;
542};
543
544#define LOCALLY_ENQUEUED 0x1
545
546#define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
547
548static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
549				     const struct net_device *dev)
550{
551	unsigned int seq;
552
553	do {
554		seq = read_seqbegin(&n->ha_lock);
555		memcpy(dst, n->ha, dev->addr_len);
556	} while (read_seqretry(&n->ha_lock, seq));
557}
558
559static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
560					  int *notify)
561{
562	u8 ndm_flags = 0;
563
564	ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
565	if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
566		if (ndm_flags & NTF_ROUTER)
567			neigh->flags |= NTF_ROUTER;
568		else
569			neigh->flags &= ~NTF_ROUTER;
570		*notify = 1;
571	}
572}
573#endif
574