1 #ifndef _NET_NEIGHBOUR_H
2 #define _NET_NEIGHBOUR_H
3 
4 #include <linux/neighbour.h>
5 
6 /*
7  *	Generic neighbour manipulation
8  *
9  *	Authors:
10  *	Pedro Roque		<roque@di.fc.ul.pt>
11  *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
12  *
13  * 	Changes:
14  *
15  *	Harald Welte:		<laforge@gnumonks.org>
16  *		- Add neighbour cache statistics like rtstat
17  */
18 
19 #include <linux/atomic.h>
20 #include <linux/netdevice.h>
21 #include <linux/skbuff.h>
22 #include <linux/rcupdate.h>
23 #include <linux/seq_file.h>
24 
25 #include <linux/err.h>
26 #include <linux/sysctl.h>
27 #include <linux/workqueue.h>
28 #include <net/rtnetlink.h>
29 
30 /*
31  * NUD stands for "neighbor unreachability detection"
32  */
33 
34 #define NUD_IN_TIMER	(NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
35 #define NUD_VALID	(NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
36 #define NUD_CONNECTED	(NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
37 
38 struct neighbour;
39 
40 struct neigh_parms {
41 #ifdef CONFIG_NET_NS
42 	struct net *net;
43 #endif
44 	struct net_device *dev;
45 	struct neigh_parms *next;
46 	int	(*neigh_setup)(struct neighbour *);
47 	void	(*neigh_cleanup)(struct neighbour *);
48 	struct neigh_table *tbl;
49 
50 	void	*sysctl_table;
51 
52 	int dead;
53 	atomic_t refcnt;
54 	struct rcu_head rcu_head;
55 
56 	int	base_reachable_time;
57 	int	retrans_time;
58 	int	gc_staletime;
59 	int	reachable_time;
60 	int	delay_probe_time;
61 
62 	int	queue_len_bytes;
63 	int	ucast_probes;
64 	int	app_probes;
65 	int	mcast_probes;
66 	int	anycast_delay;
67 	int	proxy_delay;
68 	int	proxy_qlen;
69 	int	locktime;
70 };
71 
72 struct neigh_statistics {
73 	unsigned long allocs;		/* number of allocated neighs */
74 	unsigned long destroys;		/* number of destroyed neighs */
75 	unsigned long hash_grows;	/* number of hash resizes */
76 
77 	unsigned long res_failed;	/* number of failed resolutions */
78 
79 	unsigned long lookups;		/* number of lookups */
80 	unsigned long hits;		/* number of hits (among lookups) */
81 
82 	unsigned long rcv_probes_mcast;	/* number of received mcast ipv6 */
83 	unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
84 
85 	unsigned long periodic_gc_runs;	/* number of periodic GC runs */
86 	unsigned long forced_gc_runs;	/* number of forced GC runs */
87 
88 	unsigned long unres_discards;	/* number of unresolved drops */
89 };
90 
91 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
92 
93 struct neighbour {
94 	struct neighbour __rcu	*next;
95 	struct neigh_table	*tbl;
96 	struct neigh_parms	*parms;
97 	unsigned long		confirmed;
98 	unsigned long		updated;
99 	rwlock_t		lock;
100 	atomic_t		refcnt;
101 	struct sk_buff_head	arp_queue;
102 	unsigned int		arp_queue_len_bytes;
103 	struct timer_list	timer;
104 	unsigned long		used;
105 	atomic_t		probes;
106 	__u8			flags;
107 	__u8			nud_state;
108 	__u8			type;
109 	__u8			dead;
110 	seqlock_t		ha_lock;
111 	unsigned char		ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
112 	struct hh_cache		hh;
113 	int			(*output)(struct neighbour *, struct sk_buff *);
114 	const struct neigh_ops	*ops;
115 	struct rcu_head		rcu;
116 	struct net_device	*dev;
117 	u8			primary_key[0];
118 };
119 
120 struct neigh_ops {
121 	int			family;
122 	void			(*solicit)(struct neighbour *, struct sk_buff *);
123 	void			(*error_report)(struct neighbour *, struct sk_buff *);
124 	int			(*output)(struct neighbour *, struct sk_buff *);
125 	int			(*connected_output)(struct neighbour *, struct sk_buff *);
126 };
127 
128 struct pneigh_entry {
129 	struct pneigh_entry	*next;
130 #ifdef CONFIG_NET_NS
131 	struct net		*net;
132 #endif
133 	struct net_device	*dev;
134 	u8			flags;
135 	u8			key[0];
136 };
137 
138 /*
139  *	neighbour table manipulation
140  */
141 
142 #define NEIGH_NUM_HASH_RND	4
143 
144 struct neigh_hash_table {
145 	struct neighbour __rcu	**hash_buckets;
146 	unsigned int		hash_shift;
147 	__u32			hash_rnd[NEIGH_NUM_HASH_RND];
148 	struct rcu_head		rcu;
149 };
150 
151 
152 struct neigh_table {
153 	struct neigh_table	*next;
154 	int			family;
155 	int			entry_size;
156 	int			key_len;
157 	__u32			(*hash)(const void *pkey,
158 					const struct net_device *dev,
159 					__u32 *hash_rnd);
160 	int			(*constructor)(struct neighbour *);
161 	int			(*pconstructor)(struct pneigh_entry *);
162 	void			(*pdestructor)(struct pneigh_entry *);
163 	void			(*proxy_redo)(struct sk_buff *skb);
164 	char			*id;
165 	struct neigh_parms	parms;
166 	/* HACK. gc_* should follow parms without a gap! */
167 	int			gc_interval;
168 	int			gc_thresh1;
169 	int			gc_thresh2;
170 	int			gc_thresh3;
171 	unsigned long		last_flush;
172 	struct delayed_work	gc_work;
173 	struct timer_list 	proxy_timer;
174 	struct sk_buff_head	proxy_queue;
175 	atomic_t		entries;
176 	rwlock_t		lock;
177 	unsigned long		last_rand;
178 	struct neigh_statistics	__percpu *stats;
179 	struct neigh_hash_table __rcu *nht;
180 	struct pneigh_entry	**phash_buckets;
181 };
182 
183 #define NEIGH_PRIV_ALIGN	sizeof(long long)
184 
neighbour_priv(const struct neighbour * n)185 static inline void *neighbour_priv(const struct neighbour *n)
186 {
187 	return (char *)n + ALIGN(sizeof(*n) + n->tbl->key_len, NEIGH_PRIV_ALIGN);
188 }
189 
190 /* flags for neigh_update() */
191 #define NEIGH_UPDATE_F_OVERRIDE			0x00000001
192 #define NEIGH_UPDATE_F_WEAK_OVERRIDE		0x00000002
193 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER	0x00000004
194 #define NEIGH_UPDATE_F_ISROUTER			0x40000000
195 #define NEIGH_UPDATE_F_ADMIN			0x80000000
196 
197 extern void			neigh_table_init(struct neigh_table *tbl);
198 extern void			neigh_table_init_no_netlink(struct neigh_table *tbl);
199 extern int			neigh_table_clear(struct neigh_table *tbl);
200 extern struct neighbour *	neigh_lookup(struct neigh_table *tbl,
201 					     const void *pkey,
202 					     struct net_device *dev);
203 extern struct neighbour *	neigh_lookup_nodev(struct neigh_table *tbl,
204 						   struct net *net,
205 						   const void *pkey);
206 extern struct neighbour *	neigh_create(struct neigh_table *tbl,
207 					     const void *pkey,
208 					     struct net_device *dev);
209 extern void			neigh_destroy(struct neighbour *neigh);
210 extern int			__neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
211 extern int			neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
212 					     u32 flags);
213 extern void			neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
214 extern int			neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
215 extern int			neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
216 extern int			neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
217 extern int			neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
218 extern int			neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
219 extern struct neighbour 	*neigh_event_ns(struct neigh_table *tbl,
220 						u8 *lladdr, void *saddr,
221 						struct net_device *dev);
222 
223 extern struct neigh_parms	*neigh_parms_alloc(struct net_device *dev, struct neigh_table *tbl);
224 extern void			neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
225 
226 static inline
neigh_parms_net(const struct neigh_parms * parms)227 struct net			*neigh_parms_net(const struct neigh_parms *parms)
228 {
229 	return read_pnet(&parms->net);
230 }
231 
232 extern unsigned long		neigh_rand_reach_time(unsigned long base);
233 
234 extern void			pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
235 					       struct sk_buff *skb);
236 extern struct pneigh_entry	*pneigh_lookup(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev, int creat);
237 extern struct pneigh_entry	*__pneigh_lookup(struct neigh_table *tbl,
238 						 struct net *net,
239 						 const void *key,
240 						 struct net_device *dev);
241 extern int			pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev);
242 
243 static inline
pneigh_net(const struct pneigh_entry * pneigh)244 struct net			*pneigh_net(const struct pneigh_entry *pneigh)
245 {
246 	return read_pnet(&pneigh->net);
247 }
248 
249 extern void neigh_app_ns(struct neighbour *n);
250 extern void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie);
251 extern void __neigh_for_each_release(struct neigh_table *tbl, int (*cb)(struct neighbour *));
252 extern void pneigh_for_each(struct neigh_table *tbl, void (*cb)(struct pneigh_entry *));
253 
254 struct neigh_seq_state {
255 	struct seq_net_private p;
256 	struct neigh_table *tbl;
257 	struct neigh_hash_table *nht;
258 	void *(*neigh_sub_iter)(struct neigh_seq_state *state,
259 				struct neighbour *n, loff_t *pos);
260 	unsigned int bucket;
261 	unsigned int flags;
262 #define NEIGH_SEQ_NEIGH_ONLY	0x00000001
263 #define NEIGH_SEQ_IS_PNEIGH	0x00000002
264 #define NEIGH_SEQ_SKIP_NOARP	0x00000004
265 };
266 extern void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, unsigned int);
267 extern void *neigh_seq_next(struct seq_file *, void *, loff_t *);
268 extern void neigh_seq_stop(struct seq_file *, void *);
269 
270 extern int			neigh_sysctl_register(struct net_device *dev,
271 						      struct neigh_parms *p,
272 						      char *p_name,
273 						      proc_handler *proc_handler);
274 extern void			neigh_sysctl_unregister(struct neigh_parms *p);
275 
__neigh_parms_put(struct neigh_parms * parms)276 static inline void __neigh_parms_put(struct neigh_parms *parms)
277 {
278 	atomic_dec(&parms->refcnt);
279 }
280 
neigh_parms_clone(struct neigh_parms * parms)281 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
282 {
283 	atomic_inc(&parms->refcnt);
284 	return parms;
285 }
286 
287 /*
288  *	Neighbour references
289  */
290 
neigh_release(struct neighbour * neigh)291 static inline void neigh_release(struct neighbour *neigh)
292 {
293 	if (atomic_dec_and_test(&neigh->refcnt))
294 		neigh_destroy(neigh);
295 }
296 
neigh_clone(struct neighbour * neigh)297 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
298 {
299 	if (neigh)
300 		atomic_inc(&neigh->refcnt);
301 	return neigh;
302 }
303 
304 #define neigh_hold(n)	atomic_inc(&(n)->refcnt)
305 
neigh_confirm(struct neighbour * neigh)306 static inline void neigh_confirm(struct neighbour *neigh)
307 {
308 	if (neigh)
309 		neigh->confirmed = jiffies;
310 }
311 
neigh_event_send(struct neighbour * neigh,struct sk_buff * skb)312 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
313 {
314 	unsigned long now = jiffies;
315 
316 	if (neigh->used != now)
317 		neigh->used = now;
318 	if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
319 		return __neigh_event_send(neigh, skb);
320 	return 0;
321 }
322 
323 #ifdef CONFIG_BRIDGE_NETFILTER
neigh_hh_bridge(struct hh_cache * hh,struct sk_buff * skb)324 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
325 {
326 	unsigned seq, hh_alen;
327 
328 	do {
329 		seq = read_seqbegin(&hh->hh_lock);
330 		hh_alen = HH_DATA_ALIGN(ETH_HLEN);
331 		memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
332 	} while (read_seqretry(&hh->hh_lock, seq));
333 	return 0;
334 }
335 #endif
336 
neigh_hh_output(struct hh_cache * hh,struct sk_buff * skb)337 static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
338 {
339 	unsigned seq;
340 	int hh_len;
341 
342 	do {
343 		int hh_alen;
344 
345 		seq = read_seqbegin(&hh->hh_lock);
346 		hh_len = hh->hh_len;
347 		hh_alen = HH_DATA_ALIGN(hh_len);
348 		memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
349 	} while (read_seqretry(&hh->hh_lock, seq));
350 
351 	skb_push(skb, hh_len);
352 	return dev_queue_xmit(skb);
353 }
354 
neigh_output(struct neighbour * n,struct sk_buff * skb)355 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb)
356 {
357 	struct hh_cache *hh = &n->hh;
358 	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
359 		return neigh_hh_output(hh, skb);
360 	else
361 		return n->output(n, skb);
362 }
363 
364 static inline struct neighbour *
__neigh_lookup(struct neigh_table * tbl,const void * pkey,struct net_device * dev,int creat)365 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
366 {
367 	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
368 
369 	if (n || !creat)
370 		return n;
371 
372 	n = neigh_create(tbl, pkey, dev);
373 	return IS_ERR(n) ? NULL : n;
374 }
375 
376 static inline struct neighbour *
__neigh_lookup_errno(struct neigh_table * tbl,const void * pkey,struct net_device * dev)377 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
378   struct net_device *dev)
379 {
380 	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
381 
382 	if (n)
383 		return n;
384 
385 	return neigh_create(tbl, pkey, dev);
386 }
387 
388 struct neighbour_cb {
389 	unsigned long sched_next;
390 	unsigned int flags;
391 };
392 
393 #define LOCALLY_ENQUEUED 0x1
394 
395 #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
396 
neigh_ha_snapshot(char * dst,const struct neighbour * n,const struct net_device * dev)397 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
398 				     const struct net_device *dev)
399 {
400 	unsigned int seq;
401 
402 	do {
403 		seq = read_seqbegin(&n->ha_lock);
404 		memcpy(dst, n->ha, dev->addr_len);
405 	} while (read_seqretry(&n->ha_lock, seq));
406 }
407 #endif
408