dst.h 10.7 KB
Newer Older
L
Linus Torvalds 已提交
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>
L
Linus Torvalds 已提交
13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
#include <linux/rtnetlink.h>
#include <linux/rcupdate.h>
#include <linux/jiffies.h>
#include <net/neighbour.h>
#include <asm/processor.h>

#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;

E
Eric Dumazet 已提交
32
struct dst_entry {
33
	struct rcu_head		rcu_head;
L
Linus Torvalds 已提交
34 35
	struct dst_entry	*child;
	struct net_device       *dev;
36 37
	struct  dst_ops	        *ops;
	unsigned long		_metrics;
L
Linus Torvalds 已提交
38
	unsigned long		expires;
39
	struct dst_entry	*path;
40
	struct neighbour __rcu	*_neighbour;
41
#ifdef CONFIG_XFRM
L
Linus Torvalds 已提交
42
	struct xfrm_state	*xfrm;
43 44
#else
	void			*__pad1;
45
#endif
L
Linus Torvalds 已提交
46 47 48
	int			(*input)(struct sk_buff*);
	int			(*output)(struct sk_buff*);

49 50 51 52 53 54 55
	int			flags;
#define DST_HOST		0x0001
#define DST_NOXFRM		0x0002
#define DST_NOPOLICY		0x0004
#define DST_NOHASH		0x0008
#define DST_NOCACHE		0x0010
#define DST_NOCOUNT		0x0020
E
Eric Dumazet 已提交
56
#define DST_NOPEER		0x0040
57

58 59 60 61
	short			error;
	short			obsolete;
	unsigned short		header_len;	/* more space at head required */
	unsigned short		trailer_len;	/* space to reserve at tail */
62
#ifdef CONFIG_IP_ROUTE_CLASSID
63
	__u32			tclassid;
64 65
#else
	__u32			__pad2;
66 67
#endif

68 69 70 71 72
	/*
	 * Align __refcnt to a 64 bytes alignment
	 * (L1_CACHE_SIZE would be too much)
	 */
#ifdef CONFIG_64BIT
73
	long			__pad_to_align_refcnt[2];
74
#endif
75 76 77 78
	/*
	 * __refcnt wants to be on a different cache line from
	 * input/output/ops or performance tanks badly
	 */
79 80
	atomic_t		__refcnt;	/* client references	*/
	int			__use;
81
	unsigned long		lastuse;
82
	union {
83 84 85 86
		struct dst_entry	*next;
		struct rtable __rcu	*rt_next;
		struct rt6_info		*rt6_next;
		struct dn_route __rcu	*dn_next;
87
	};
L
Linus Torvalds 已提交
88 89
};

90 91
static inline struct neighbour *dst_get_neighbour(struct dst_entry *dst)
{
92 93 94 95 96 97
	return rcu_dereference(dst->_neighbour);
}

static inline struct neighbour *dst_get_neighbour_raw(struct dst_entry *dst)
{
	return rcu_dereference_raw(dst->_neighbour);
98 99 100 101
}

static inline void dst_set_neighbour(struct dst_entry *dst, struct neighbour *neigh)
{
102
	rcu_assign_pointer(dst->_neighbour, neigh);
103 104
}

105
extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
106
extern const u32 dst_default_metrics[RTAX_MAX];
107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130

#define DST_METRICS_READ_ONLY	0x1UL
#define __DST_METRICS_PTR(Y)	\
	((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
#define DST_METRICS_PTR(X)	__DST_METRICS_PTR((X)->_metrics)

static inline bool dst_metrics_read_only(const struct dst_entry *dst)
{
	return dst->_metrics & DST_METRICS_READ_ONLY;
}

extern void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);

static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
{
	unsigned long val = dst->_metrics;
	if (!(val & DST_METRICS_READ_ONLY))
		__dst_destroy_metrics_generic(dst, val);
}

static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
{
	unsigned long p = dst->_metrics;

131 132
	BUG_ON(!p);

133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164
	if (p & DST_METRICS_READ_ONLY)
		return dst->ops->cow_metrics(dst, p);
	return __DST_METRICS_PTR(p);
}

/* This may only be invoked before the entry has reached global
 * visibility.
 */
static inline void dst_init_metrics(struct dst_entry *dst,
				    const u32 *src_metrics,
				    bool read_only)
{
	dst->_metrics = ((unsigned long) src_metrics) |
		(read_only ? DST_METRICS_READ_ONLY : 0);
}

static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
{
	u32 *dst_metrics = dst_metrics_write_ptr(dest);

	if (dst_metrics) {
		u32 *src_metrics = DST_METRICS_PTR(src);

		memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
	}
}

static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
{
	return DST_METRICS_PTR(dst);
}

L
Linus Torvalds 已提交
165
static inline u32
166
dst_metric_raw(const struct dst_entry *dst, const int metric)
L
Linus Torvalds 已提交
167
{
168 169 170
	u32 *p = DST_METRICS_PTR(dst);

	return p[metric-1];
171 172
}

173 174 175
static inline u32
dst_metric(const struct dst_entry *dst, const int metric)
{
176
	WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
177 178
		     metric == RTAX_ADVMSS ||
		     metric == RTAX_MTU);
179 180 181
	return dst_metric_raw(dst, metric);
}

182 183 184 185 186 187 188 189 190 191 192
static inline u32
dst_metric_advmss(const struct dst_entry *dst)
{
	u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);

	if (!advmss)
		advmss = dst->ops->default_advmss(dst);

	return advmss;
}

193 194
static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
{
195
	u32 *p = dst_metrics_write_ptr(dst);
196

197 198
	if (p)
		p[metric-1] = val;
L
Linus Torvalds 已提交
199 200
}

201 202 203
static inline u32
dst_feature(const struct dst_entry *dst, u32 feature)
{
204
	return dst_metric(dst, RTAX_FEATURES) & feature;
205 206
}

L
Linus Torvalds 已提交
207 208
static inline u32 dst_mtu(const struct dst_entry *dst)
{
209
	return dst->ops->mtu(dst);
L
Linus Torvalds 已提交
210 211
}

S
Stephen Hemminger 已提交
212 213 214 215 216 217 218 219 220
/* 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)
{
221
	dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
S
Stephen Hemminger 已提交
222 223
}

L
Linus Torvalds 已提交
224 225 226
static inline u32
dst_allfrag(const struct dst_entry *dst)
{
227
	int ret = dst_feature(dst,  RTAX_FEATURE_ALLFRAG);
L
Linus Torvalds 已提交
228 229 230 231
	return ret;
}

static inline int
232
dst_metric_locked(const struct dst_entry *dst, int metric)
L
Linus Torvalds 已提交
233 234 235 236 237 238
{
	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
}

static inline void dst_hold(struct dst_entry * dst)
{
239 240 241 242 243
	/*
	 * 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);
L
Linus Torvalds 已提交
244 245 246
	atomic_inc(&dst->__refcnt);
}

247 248 249 250 251 252 253
static inline void dst_use(struct dst_entry *dst, unsigned long time)
{
	dst_hold(dst);
	dst->__use++;
	dst->lastuse = time;
}

E
Eric Dumazet 已提交
254 255 256 257 258 259
static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
{
	dst->__use++;
	dst->lastuse = time;
}

L
Linus Torvalds 已提交
260 261 262 263 264 265 266 267
static inline
struct dst_entry * dst_clone(struct dst_entry * dst)
{
	if (dst)
		atomic_inc(&dst->__refcnt);
	return dst;
}

I
Ilpo Järvinen 已提交
268
extern void dst_release(struct dst_entry *dst);
E
Eric Dumazet 已提交
269 270 271 272 273 274 275 276 277 278 279 280 281

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.
 */
E
Eric Dumazet 已提交
282 283
static inline void skb_dst_drop(struct sk_buff *skb)
{
E
Eric Dumazet 已提交
284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309
	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));
	}
E
Eric Dumazet 已提交
310
}
L
Linus Torvalds 已提交
311

312

313 314 315 316 317 318 319 320 321 322 323
/**
 *	__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. (no accounting done)
 */
static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
{
	skb->dev = dev;
324 325 326 327 328 329 330 331

	/*
	 * Clear rxhash so that we can recalulate the hash for the
	 * encapsulated packet, unless we have already determine the hash
	 * over the L4 4-tuple.
	 */
	if (!skb->l4_rxhash)
		skb->rxhash = 0;
332 333 334 335 336
	skb_set_queue_mapping(skb, 0);
	skb_dst_drop(skb);
	nf_reset(skb);
}

337 338 339 340 341 342 343
/**
 *	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.
344
 *	Note: this accounting is not SMP safe.
345 346 347 348 349 350
 */
static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
{
	/* TODO : stats should be SMP safe */
	dev->stats.rx_packets++;
	dev->stats.rx_bytes += skb->len;
351
	__skb_tunnel_rx(skb, dev);
352 353
}

L
Linus Torvalds 已提交
354 355 356 357
/* Children define the path of the packet through the
 * Linux networking.  Thus, destinations are stackable.
 */

358
static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
L
Linus Torvalds 已提交
359
{
360
	struct dst_entry *child = dst_clone(skb_dst(skb)->child);
L
Linus Torvalds 已提交
361

362
	skb_dst_drop(skb);
L
Linus Torvalds 已提交
363 364 365
	return child;
}

366
extern int dst_discard(struct sk_buff *skb);
367 368
extern void *dst_alloc(struct dst_ops * ops, struct net_device *dev,
		       int initial_ref, int initial_obsolete, int flags);
L
Linus Torvalds 已提交
369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391
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)
{
392
	if (dst) {
393 394 395 396
		struct neighbour *n;

		rcu_read_lock();
		n = dst_get_neighbour(dst);
397
		neigh_confirm(n);
398
		rcu_read_unlock();
399
	}
L
Linus Torvalds 已提交
400 401
}

402 403 404 405 406
static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
{
	return dst->ops->neigh_lookup(dst, daddr);
}

L
Linus Torvalds 已提交
407 408
static inline void dst_link_failure(struct sk_buff *skb)
{
E
Eric Dumazet 已提交
409
	struct dst_entry *dst = skb_dst(skb);
L
Linus Torvalds 已提交
410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427
	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)
{
E
Eric Dumazet 已提交
428
	return skb_dst(skb)->output(skb);
L
Linus Torvalds 已提交
429 430 431 432 433
}

/* Input packet from network to transport.  */
static inline int dst_input(struct sk_buff *skb)
{
E
Eric Dumazet 已提交
434
	return skb_dst(skb)->input(skb);
L
Linus Torvalds 已提交
435 436 437 438 439 440 441 442 443 444 445
}

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);

446 447
/* Flags for xfrm_lookup flags argument. */
enum {
448
	XFRM_LOOKUP_ICMP = 1 << 0,
449 450
};

L
Linus Torvalds 已提交
451 452
struct flowi;
#ifndef CONFIG_XFRM
453 454 455 456
static inline struct dst_entry *xfrm_lookup(struct net *net,
					    struct dst_entry *dst_orig,
					    const struct flowi *fl, struct sock *sk,
					    int flags)
L
Linus Torvalds 已提交
457
{
458
	return dst_orig;
L
Linus Torvalds 已提交
459 460
} 
#else
461 462 463
extern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
				     const struct flowi *fl, struct sock *sk,
				     int flags);
L
Linus Torvalds 已提交
464 465 466
#endif

#endif /* _NET_DST_H */