dst.h 7.82 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
10
/*
 * net/dst.h	Protocol independent destination cache definitions.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 */

#ifndef _NET_DST_H
#define _NET_DST_H

11
#include <net/dst_ops.h>
12
#include <linux/netdevice.h>
Linus Torvalds's avatar
Linus Torvalds committed
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
#include <linux/rtnetlink.h>
#include <linux/rcupdate.h>
#include <linux/jiffies.h>
#include <net/neighbour.h>
#include <asm/processor.h>

/*
 * 0 - no debugging messages
 * 1 - rare events and bugs (default)
 * 2 - trace mode.
 */
#define RT_CACHE_DEBUG		0

#define DST_GC_MIN	(HZ/10)
#define DST_GC_INC	(HZ/2)
#define DST_GC_MAX	(120*HZ)

/* Each dst_entry has reference count and sits in some parent list(s).
 * When it is removed from parent list, it is "freed" (dst_free).
 * After this it enters dead state (dst->obsolete > 0) and if its refcnt
 * is zero, it can be destroyed immediately, otherwise it is added
 * to gc list and garbage collector periodically checks the refcnt.
 */

struct sk_buff;

Eric Dumazet's avatar
Eric Dumazet committed
39
struct dst_entry {
40
	struct rcu_head		rcu_head;
Linus Torvalds's avatar
Linus Torvalds committed
41
42
	struct dst_entry	*child;
	struct net_device       *dev;
43
44
	short			error;
	short			obsolete;
Linus Torvalds's avatar
Linus Torvalds committed
45
46
47
48
49
50
51
52
53
54
	int			flags;
#define DST_HOST		1
#define DST_NOXFRM		2
#define DST_NOPOLICY		4
#define DST_NOHASH		8
	unsigned long		expires;

	unsigned short		header_len;	/* more space at head required */
	unsigned short		trailer_len;	/* space to reserve at tail */

55
	unsigned int		rate_tokens;
56
	unsigned long		rate_last;	/* rate limiting for ICMP */
57

58
	struct dst_entry	*path;
Linus Torvalds's avatar
Linus Torvalds committed
59
60
61

	struct neighbour	*neighbour;
	struct hh_cache		*hh;
62
#ifdef CONFIG_XFRM
Linus Torvalds's avatar
Linus Torvalds committed
63
	struct xfrm_state	*xfrm;
64
65
#else
	void			*__pad1;
66
#endif
Linus Torvalds's avatar
Linus Torvalds committed
67
68
69
70
	int			(*input)(struct sk_buff*);
	int			(*output)(struct sk_buff*);

	struct  dst_ops	        *ops;
71
72
73
74
75

	u32			metrics[RTAX_MAX];

#ifdef CONFIG_NET_CLS_ROUTE
	__u32			tclassid;
76
77
#else
	__u32			__pad2;
78
79
#endif

80
81
82
83
84
85
86
87

	/*
	 * Align __refcnt to a 64 bytes alignment
	 * (L1_CACHE_SIZE would be too much)
	 */
#ifdef CONFIG_64BIT
	long			__pad_to_align_refcnt[1];
#endif
88
89
90
91
	/*
	 * __refcnt wants to be on a different cache line from
	 * input/output/ops or performance tanks badly
	 */
92
93
	atomic_t		__refcnt;	/* client references	*/
	int			__use;
94
	unsigned long		lastuse;
95
96
97
98
99
100
	union {
		struct dst_entry *next;
		struct rtable    *rt_next;
		struct rt6_info   *rt6_next;
		struct dn_route  *dn_next;
	};
Linus Torvalds's avatar
Linus Torvalds committed
101
102
103
104
105
106
107
108
109
110
};

#ifdef __KERNEL__

static inline u32
dst_metric(const struct dst_entry *dst, int metric)
{
	return dst->metrics[metric-1];
}

111
112
113
static inline u32
dst_feature(const struct dst_entry *dst, u32 feature)
{
114
	return dst_metric(dst, RTAX_FEATURES) & feature;
115
116
}

Linus Torvalds's avatar
Linus Torvalds committed
117
118
119
120
121
122
123
124
125
126
static inline u32 dst_mtu(const struct dst_entry *dst)
{
	u32 mtu = dst_metric(dst, RTAX_MTU);
	/*
	 * Alexey put it here, so ask him about it :)
	 */
	barrier();
	return mtu;
}

Stephen Hemminger's avatar
Stephen Hemminger committed
127
128
129
130
131
132
133
134
135
136
137
138
/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
{
	return msecs_to_jiffies(dst_metric(dst, metric));
}

static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
				      unsigned long rtt)
{
	dst->metrics[metric-1] = jiffies_to_msecs(rtt);
}

Linus Torvalds's avatar
Linus Torvalds committed
139
140
141
static inline u32
dst_allfrag(const struct dst_entry *dst)
{
142
	int ret = dst_feature(dst,  RTAX_FEATURE_ALLFRAG);
Linus Torvalds's avatar
Linus Torvalds committed
143
144
145
146
147
148
149
150
151
152
153
154
155
	/* Yes, _exactly_. This is paranoia. */
	barrier();
	return ret;
}

static inline int
dst_metric_locked(struct dst_entry *dst, int metric)
{
	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
}

static inline void dst_hold(struct dst_entry * dst)
{
156
157
158
159
160
	/*
	 * If your kernel compilation stops here, please check
	 * __pad_to_align_refcnt declaration in struct dst_entry
	 */
	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
Linus Torvalds's avatar
Linus Torvalds committed
161
162
163
	atomic_inc(&dst->__refcnt);
}

164
165
166
167
168
169
170
static inline void dst_use(struct dst_entry *dst, unsigned long time)
{
	dst_hold(dst);
	dst->__use++;
	dst->lastuse = time;
}

Eric Dumazet's avatar
Eric Dumazet committed
171
172
173
174
175
176
static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
{
	dst->__use++;
	dst->lastuse = time;
}

Linus Torvalds's avatar
Linus Torvalds committed
177
178
179
180
181
182
183
184
static inline
struct dst_entry * dst_clone(struct dst_entry * dst)
{
	if (dst)
		atomic_inc(&dst->__refcnt);
	return dst;
}

Ilpo Järvinen's avatar
Ilpo Järvinen committed
185
extern void dst_release(struct dst_entry *dst);
Eric Dumazet's avatar
Eric Dumazet committed
186
187
188
189
190
191
192
193
194
195
196
197
198

static inline void refdst_drop(unsigned long refdst)
{
	if (!(refdst & SKB_DST_NOREF))
		dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
}

/**
 * skb_dst_drop - drops skb dst
 * @skb: buffer
 *
 * Drops dst reference count if a reference was taken.
 */
Eric Dumazet's avatar
Eric Dumazet committed
199
200
static inline void skb_dst_drop(struct sk_buff *skb)
{
Eric Dumazet's avatar
Eric Dumazet committed
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
	if (skb->_skb_refdst) {
		refdst_drop(skb->_skb_refdst);
		skb->_skb_refdst = 0UL;
	}
}

static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
{
	nskb->_skb_refdst = oskb->_skb_refdst;
	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
		dst_clone(skb_dst(nskb));
}

/**
 * skb_dst_force - makes sure skb dst is refcounted
 * @skb: buffer
 *
 * If dst is not yet refcounted, let's do it
 */
static inline void skb_dst_force(struct sk_buff *skb)
{
	if (skb_dst_is_noref(skb)) {
		WARN_ON(!rcu_read_lock_held());
		skb->_skb_refdst &= ~SKB_DST_NOREF;
		dst_clone(skb_dst(skb));
	}
Eric Dumazet's avatar
Eric Dumazet committed
227
}
Linus Torvalds's avatar
Linus Torvalds committed
228

229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244

/**
 *	skb_tunnel_rx - prepare skb for rx reinsert
 *	@skb: buffer
 *	@dev: tunnel device
 *
 *	After decapsulation, packet is going to re-enter (netif_rx()) our stack,
 *	so make some cleanups, and perform accounting.
 */
static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
{
	skb->dev = dev;
	/* TODO : stats should be SMP safe */
	dev->stats.rx_packets++;
	dev->stats.rx_bytes += skb->len;
	skb->rxhash = 0;
245
	skb_set_queue_mapping(skb, 0);
246
247
248
249
	skb_dst_drop(skb);
	nf_reset(skb);
}

Linus Torvalds's avatar
Linus Torvalds committed
250
251
252
253
/* Children define the path of the packet through the
 * Linux networking.  Thus, destinations are stackable.
 */

254
static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
Linus Torvalds's avatar
Linus Torvalds committed
255
{
256
	struct dst_entry *child = skb_dst(skb)->child;
Linus Torvalds's avatar
Linus Torvalds committed
257

258
	skb_dst_drop(skb);
Linus Torvalds's avatar
Linus Torvalds committed
259
260
261
	return child;
}

262
extern int dst_discard(struct sk_buff *skb);
Linus Torvalds's avatar
Linus Torvalds committed
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
extern void * dst_alloc(struct dst_ops * ops);
extern void __dst_free(struct dst_entry * dst);
extern struct dst_entry *dst_destroy(struct dst_entry * dst);

static inline void dst_free(struct dst_entry * dst)
{
	if (dst->obsolete > 1)
		return;
	if (!atomic_read(&dst->__refcnt)) {
		dst = dst_destroy(dst);
		if (!dst)
			return;
	}
	__dst_free(dst);
}

static inline void dst_rcu_free(struct rcu_head *head)
{
	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
	dst_free(dst);
}

static inline void dst_confirm(struct dst_entry *dst)
{
	if (dst)
		neigh_confirm(dst->neighbour);
}

static inline void dst_link_failure(struct sk_buff *skb)
{
Eric Dumazet's avatar
Eric Dumazet committed
293
	struct dst_entry *dst = skb_dst(skb);
Linus Torvalds's avatar
Linus Torvalds committed
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
	if (dst && dst->ops && dst->ops->link_failure)
		dst->ops->link_failure(skb);
}

static inline void dst_set_expires(struct dst_entry *dst, int timeout)
{
	unsigned long expires = jiffies + timeout;

	if (expires == 0)
		expires = 1;

	if (dst->expires == 0 || time_before(expires, dst->expires))
		dst->expires = expires;
}

/* Output packet to network from transport.  */
static inline int dst_output(struct sk_buff *skb)
{
Eric Dumazet's avatar
Eric Dumazet committed
312
	return skb_dst(skb)->output(skb);
Linus Torvalds's avatar
Linus Torvalds committed
313
314
315
316
317
}

/* Input packet from network to transport.  */
static inline int dst_input(struct sk_buff *skb)
{
Eric Dumazet's avatar
Eric Dumazet committed
318
	return skb_dst(skb)->input(skb);
Linus Torvalds's avatar
Linus Torvalds committed
319
320
321
322
323
324
325
326
327
328
329
}

static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
{
	if (dst->obsolete)
		dst = dst->ops->check(dst, cookie);
	return dst;
}

extern void		dst_init(void);

330
331
332
/* Flags for xfrm_lookup flags argument. */
enum {
	XFRM_LOOKUP_WAIT = 1 << 0,
333
	XFRM_LOOKUP_ICMP = 1 << 1,
334
335
};

Linus Torvalds's avatar
Linus Torvalds committed
336
337
struct flowi;
#ifndef CONFIG_XFRM
Alexey Dobriyan's avatar
Alexey Dobriyan committed
338
339
static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
			      struct flowi *fl, struct sock *sk, int flags)
Linus Torvalds's avatar
Linus Torvalds committed
340
341
342
{
	return 0;
} 
Alexey Dobriyan's avatar
Alexey Dobriyan committed
343
344
static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
				struct flowi *fl, struct sock *sk, int flags)
345
346
347
{
	return 0;
}
Linus Torvalds's avatar
Linus Torvalds committed
348
#else
Alexey Dobriyan's avatar
Alexey Dobriyan committed
349
350
351
352
extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
		       struct flowi *fl, struct sock *sk, int flags);
extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
			 struct flowi *fl, struct sock *sk, int flags);
Linus Torvalds's avatar
Linus Torvalds committed
353
354
355
356
#endif
#endif

#endif /* _NET_DST_H */