[deliverable/linux.git] / include / net / dst.h

/*
 * net/dst.h	Protocol independent destination cache definitions.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 */

#ifndef _NET_DST_H
#define _NET_DST_H

#include <net/dst_ops.h>
#include <linux/netdevice.h>
#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;

struct dst_entry {
	struct rcu_head		rcu_head;
	struct dst_entry	*child;
	struct net_device       *dev;
	struct  dst_ops	        *ops;
	unsigned long		_metrics;
	unsigned long		expires;
	struct dst_entry	*path;
	struct neighbour	*neighbour;
	struct hh_cache		*hh;
#ifdef CONFIG_XFRM
	struct xfrm_state	*xfrm;
#else
	void			*__pad1;
#endif
	int			(*input)(struct sk_buff*);
	int			(*output)(struct sk_buff*);

	short			error;
	short			obsolete;
	unsigned short		header_len;	/* more space at head required */
	unsigned short		trailer_len;	/* space to reserve at tail */
#ifdef CONFIG_IP_ROUTE_CLASSID
	__u32			tclassid;
#else
	__u32			__pad2;
#endif

	/*
	 * Align __refcnt to a 64 bytes alignment
	 * (L1_CACHE_SIZE would be too much)
	 */
#ifdef CONFIG_64BIT
	long			__pad_to_align_refcnt[1];
#endif
	/*
	 * __refcnt wants to be on a different cache line from
	 * input/output/ops or performance tanks badly
	 */
	atomic_t		__refcnt;	/* client references	*/
	int			__use;
	unsigned long		lastuse;
	unsigned long		rate_last;	/* rate limiting for ICMP */
	unsigned int		rate_tokens;
	int			flags;
#define DST_HOST		0x0001
#define DST_NOXFRM		0x0002
#define DST_NOPOLICY		0x0004
#define DST_NOHASH		0x0008
#define DST_NOCACHE		0x0010
	union {
		struct dst_entry	*next;
		struct rtable __rcu	*rt_next;
		struct rt6_info		*rt6_next;
		struct dn_route __rcu	*dn_next;
	};
};

#ifdef __KERNEL__

extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);

#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;

	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);
}

static inline u32
dst_metric_raw(const struct dst_entry *dst, const int metric)
{
	u32 *p = DST_METRICS_PTR(dst);

	return p[metric-1];
}

static inline u32
dst_metric(const struct dst_entry *dst, const int metric)
{
	WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
		     metric == RTAX_ADVMSS ||
		     metric == RTAX_MTU);
	return dst_metric_raw(dst, metric);
}

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;
}

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

	if (p)
		p[metric-1] = val;
}

static inline u32
dst_feature(const struct dst_entry *dst, u32 feature)
{
	return dst_metric(dst, RTAX_FEATURES) & feature;
}

static inline u32 dst_mtu(const struct dst_entry *dst)
{
	u32 mtu = dst_metric_raw(dst, RTAX_MTU);

	if (!mtu)
		mtu = dst->ops->default_mtu(dst);

	return mtu;
}

/* 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_metric_set(dst, metric, jiffies_to_msecs(rtt));
}

static inline u32
dst_allfrag(const struct dst_entry *dst)
{
	int ret = dst_feature(dst,  RTAX_FEATURE_ALLFRAG);
	/* Yes, _exactly_. This is paranoia. */
	barrier();
	return ret;
}

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

static inline void dst_hold(struct dst_entry * dst)
{
	/*
	 * 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);
	atomic_inc(&dst->__refcnt);
}

static inline void dst_use(struct dst_entry *dst, unsigned long time)
{
	dst_hold(dst);
	dst->__use++;
	dst->lastuse = time;
}

static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
{
	dst->__use++;
	dst->lastuse = time;
}

static inline
struct dst_entry * dst_clone(struct dst_entry * dst)
{
	if (dst)
		atomic_inc(&dst->__refcnt);
	return dst;
}

extern void dst_release(struct dst_entry *dst);

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.
 */
static inline void skb_dst_drop(struct sk_buff *skb)
{
	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));
	}
}


/**
 *	__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;
	skb->rxhash = 0;
	skb_set_queue_mapping(skb, 0);
	skb_dst_drop(skb);
	nf_reset(skb);
}

/**
 *	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.
 *	Note: this accounting is not SMP safe.
 */
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;
	__skb_tunnel_rx(skb, dev);
}

/* Children define the path of the packet through the
 * Linux networking.  Thus, destinations are stackable.
 */

static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
{
	struct dst_entry *child = skb_dst(skb)->child;

	skb_dst_drop(skb);
	return child;
}

extern int dst_discard(struct sk_buff *skb);
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)
{
	struct dst_entry *dst = skb_dst(skb);
	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)
{
	return skb_dst(skb)->output(skb);
}

/* Input packet from network to transport.  */
static inline int dst_input(struct sk_buff *skb)
{
	return skb_dst(skb)->input(skb);
}

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);

/* Flags for xfrm_lookup flags argument. */
enum {
	XFRM_LOOKUP_WAIT = 1 << 0,
	XFRM_LOOKUP_ICMP = 1 << 1,
};

struct flowi;
#ifndef CONFIG_XFRM
static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
			      struct flowi *fl, struct sock *sk, int flags)
{
	return 0;
} 
static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
				struct flowi *fl, struct sock *sk, int flags)
{
	return 0;
}
#else
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);
#endif
#endif

#endif /* _NET_DST_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* net/dst.h Protocol independent destination cache definitions.
	3	*
	4	* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	5	*
	6	*/
	7
	8	#ifndef _NET_DST_H
	9	#define _NET_DST_H
	10
86393e52	11	#include <net/dst_ops.h>
14c85021	12	#include <linux/netdevice.h>
1da177e4 LT	13	#include <linux/rtnetlink.h>
	14	#include <linux/rcupdate.h>
	15	#include <linux/jiffies.h>
	16	#include <net/neighbour.h>
	17	#include <asm/processor.h>
	18
	19	/*
	20	* 0 - no debugging messages
	21	* 1 - rare events and bugs (default)
	22	* 2 - trace mode.
	23	*/
	24	#define RT_CACHE_DEBUG 0
	25
	26	#define DST_GC_MIN (HZ/10)
	27	#define DST_GC_INC (HZ/2)
	28	#define DST_GC_MAX (120*HZ)
	29
	30	/* Each dst_entry has reference count and sits in some parent list(s).
	31	* When it is removed from parent list, it is "freed" (dst_free).
	32	* After this it enters dead state (dst->obsolete > 0) and if its refcnt
	33	* is zero, it can be destroyed immediately, otherwise it is added
	34	* to gc list and garbage collector periodically checks the refcnt.
	35	*/
	36
	37	struct sk_buff;
	38
fd2c3ef7	39	struct dst_entry {
1e19e02c	40	struct rcu_head rcu_head;
1da177e4 LT	41	struct dst_entry *child;
1da177e4 LT	42	struct net_device *dev;
62fa8a84 DM	43	struct dst_ops *ops;
62fa8a84 DM	44	unsigned long _metrics;
1da177e4	45	unsigned long expires;
f1dd9c37	46	struct dst_entry *path;
1da177e4 LT	47	struct neighbour *neighbour;
1da177e4 LT	48	struct hh_cache *hh;
def8b4fa	49	#ifdef CONFIG_XFRM
1da177e4	50	struct xfrm_state *xfrm;
5635c10d ED	51	#else
5635c10d ED	52	void *__pad1;
def8b4fa	53	#endif
1da177e4 LT	54	int (input)(struct sk_buff);
	55	int (output)(struct sk_buff);
	56
62fa8a84 DM	57	short error;
	58	short obsolete;
	59	unsigned short header_len; /* more space at head required */
	60	unsigned short trailer_len; /* space to reserve at tail */
c7066f70	61	#ifdef CONFIG_IP_ROUTE_CLASSID
f1dd9c37	62	__u32 tclassid;
5635c10d ED	63	#else
5635c10d ED	64	__u32 __pad2;
f1dd9c37 ZY	65	#endif
f1dd9c37 ZY	66
5635c10d ED	67	/*
	68	* Align __refcnt to a 64 bytes alignment
	69	* (L1_CACHE_SIZE would be too much)
	70	*/
	71	#ifdef CONFIG_64BIT
5635c10d ED	72	long __pad_to_align_refcnt[1];
5635c10d ED	73	#endif
f1dd9c37 ZY	74	/*
	75	* __refcnt wants to be on a different cache line from
	76	* input/output/ops or performance tanks badly
	77	*/
1e19e02c ED	78	atomic_t __refcnt; /* client references */
1e19e02c ED	79	int __use;
f1dd9c37	80	unsigned long lastuse;
62fa8a84 DM	81	unsigned long rate_last; /* rate limiting for ICMP */
	82	unsigned int rate_tokens;
	83	int flags;
	84	#define DST_HOST 0x0001
	85	#define DST_NOXFRM 0x0002
	86	#define DST_NOPOLICY 0x0004
	87	#define DST_NOHASH 0x0008
	88	#define DST_NOCACHE 0x0010
1e19e02c	89	union {
fc766e4c ED	90	struct dst_entry *next;
	91	struct rtable __rcu *rt_next;
	92	struct rt6_info *rt6_next;
	93	struct dn_route __rcu *dn_next;
1e19e02c	94	};
1da177e4 LT	95	};
1da177e4 LT	96
1da177e4 LT	97	#ifdef __KERNEL__
1da177e4 LT	98
62fa8a84 DM	99	extern u32 dst_cow_metrics_generic(struct dst_entry dst, unsigned long old);
	100
	101	#define DST_METRICS_READ_ONLY 0x1UL
	102	#define __DST_METRICS_PTR(Y) \
	103	((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
	104	#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
	105
	106	static inline bool dst_metrics_read_only(const struct dst_entry *dst)
	107	{
	108	return dst->_metrics & DST_METRICS_READ_ONLY;
	109	}
	110
	111	extern void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
	112
	113	static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
	114	{
	115	unsigned long val = dst->_metrics;
	116	if (!(val & DST_METRICS_READ_ONLY))
	117	__dst_destroy_metrics_generic(dst, val);
	118	}
	119
	120	static inline u32 dst_metrics_write_ptr(struct dst_entry dst)
	121	{
	122	unsigned long p = dst->_metrics;
	123
	124	if (p & DST_METRICS_READ_ONLY)
	125	return dst->ops->cow_metrics(dst, p);
	126	return __DST_METRICS_PTR(p);
	127	}
	128
	129	/* This may only be invoked before the entry has reached global
	130	* visibility.
	131	*/
	132	static inline void dst_init_metrics(struct dst_entry *dst,
	133	const u32 *src_metrics,
	134	bool read_only)
	135	{
	136	dst->_metrics = ((unsigned long) src_metrics) \|
	137	(read_only ? DST_METRICS_READ_ONLY : 0);
	138	}
	139
	140	static inline void dst_copy_metrics(struct dst_entry dest, const struct dst_entry src)
	141	{
	142	u32 *dst_metrics = dst_metrics_write_ptr(dest);
	143
	144	if (dst_metrics) {
	145	u32 *src_metrics = DST_METRICS_PTR(src);
	146
	147	memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
	148	}
	149	}
	150
	151	static inline u32 dst_metrics_ptr(struct dst_entry dst)
	152	{
	153	return DST_METRICS_PTR(dst);
	154	}
	155
1da177e4	156	static inline u32
5170ae82	157	dst_metric_raw(const struct dst_entry *dst, const int metric)
1da177e4	158	{
62fa8a84 DM	159	u32 *p = DST_METRICS_PTR(dst);
	160
	161	return p[metric-1];
defb3519 DM	162	}
defb3519 DM	163
5170ae82 DM	164	static inline u32
	165	dst_metric(const struct dst_entry *dst, const int metric)
	166	{
0dbaee3b	167	WARN_ON_ONCE(metric == RTAX_HOPLIMIT \|\|
d33e4553 DM	168	metric == RTAX_ADVMSS \|\|
d33e4553 DM	169	metric == RTAX_MTU);
5170ae82 DM	170	return dst_metric_raw(dst, metric);
	171	}
	172
0dbaee3b DM	173	static inline u32
	174	dst_metric_advmss(const struct dst_entry *dst)
	175	{
	176	u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
	177
	178	if (!advmss)
	179	advmss = dst->ops->default_advmss(dst);
	180
	181	return advmss;
	182	}
	183
defb3519 DM	184	static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
defb3519 DM	185	{
62fa8a84	186	u32 *p = dst_metrics_write_ptr(dst);
defb3519	187
62fa8a84 DM	188	if (p)
62fa8a84 DM	189	p[metric-1] = val;
1da177e4 LT	190	}
1da177e4 LT	191
0c3adfb8 GBY	192	static inline u32
	193	dst_feature(const struct dst_entry *dst, u32 feature)
	194	{
bb5b7c11	195	return dst_metric(dst, RTAX_FEATURES) & feature;
0c3adfb8 GBY	196	}
0c3adfb8 GBY	197
1da177e4 LT	198	static inline u32 dst_mtu(const struct dst_entry *dst)
1da177e4 LT	199	{
d33e4553 DM	200	u32 mtu = dst_metric_raw(dst, RTAX_MTU);
	201
	202	if (!mtu)
	203	mtu = dst->ops->default_mtu(dst);
	204
1da177e4 LT	205	return mtu;
	206	}
	207
c1e20f7c SH	208	/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
	209	static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
	210	{
	211	return msecs_to_jiffies(dst_metric(dst, metric));
	212	}
	213
	214	static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
	215	unsigned long rtt)
	216	{
defb3519	217	dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
c1e20f7c SH	218	}
c1e20f7c SH	219
1da177e4 LT	220	static inline u32
	221	dst_allfrag(const struct dst_entry *dst)
	222	{
0c3adfb8	223	int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
1da177e4 LT	224	/* Yes, _exactly_. This is paranoia. */
	225	barrier();
	226	return ret;
	227	}
	228
	229	static inline int
d33e4553	230	dst_metric_locked(const struct dst_entry *dst, int metric)
1da177e4 LT	231	{
	232	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	233	}
	234
	235	static inline void dst_hold(struct dst_entry * dst)
	236	{
5635c10d ED	237	/*
	238	* If your kernel compilation stops here, please check
	239	* __pad_to_align_refcnt declaration in struct dst_entry
	240	*/
	241	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
1da177e4 LT	242	atomic_inc(&dst->__refcnt);
	243	}
	244
03f49f34 PE	245	static inline void dst_use(struct dst_entry *dst, unsigned long time)
	246	{
	247	dst_hold(dst);
	248	dst->__use++;
	249	dst->lastuse = time;
	250	}
	251
7fee226a ED	252	static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
	253	{
	254	dst->__use++;
	255	dst->lastuse = time;
	256	}
	257
1da177e4 LT	258	static inline
	259	struct dst_entry * dst_clone(struct dst_entry * dst)
	260	{
	261	if (dst)
	262	atomic_inc(&dst->__refcnt);
	263	return dst;
	264	}
	265
8d330868	266	extern void dst_release(struct dst_entry *dst);
7fee226a ED	267
	268	static inline void refdst_drop(unsigned long refdst)
	269	{
	270	if (!(refdst & SKB_DST_NOREF))
	271	dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
	272	}
	273
	274	/**
	275	* skb_dst_drop - drops skb dst
	276	* @skb: buffer
	277	*
	278	* Drops dst reference count if a reference was taken.
	279	*/
adf30907 ED	280	static inline void skb_dst_drop(struct sk_buff *skb)
adf30907 ED	281	{
7fee226a ED	282	if (skb->_skb_refdst) {
	283	refdst_drop(skb->_skb_refdst);
	284	skb->_skb_refdst = 0UL;
	285	}
	286	}
	287
	288	static inline void skb_dst_copy(struct sk_buff nskb, const struct sk_buff oskb)
	289	{
	290	nskb->_skb_refdst = oskb->_skb_refdst;
	291	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
	292	dst_clone(skb_dst(nskb));
	293	}
	294
	295	/**
	296	* skb_dst_force - makes sure skb dst is refcounted
	297	* @skb: buffer
	298	*
	299	* If dst is not yet refcounted, let's do it
	300	*/
	301	static inline void skb_dst_force(struct sk_buff *skb)
	302	{
	303	if (skb_dst_is_noref(skb)) {
	304	WARN_ON(!rcu_read_lock_held());
	305	skb->_skb_refdst &= ~SKB_DST_NOREF;
	306	dst_clone(skb_dst(skb));
	307	}
adf30907	308	}
1da177e4	309
d19d56dd	310
290b895e ED	311	/**
	312	* __skb_tunnel_rx - prepare skb for rx reinsert
	313	* @skb: buffer
	314	* @dev: tunnel device
	315	*
	316	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	317	* so make some cleanups. (no accounting done)
	318	*/
	319	static inline void __skb_tunnel_rx(struct sk_buff skb, struct net_device dev)
	320	{
	321	skb->dev = dev;
	322	skb->rxhash = 0;
	323	skb_set_queue_mapping(skb, 0);
	324	skb_dst_drop(skb);
	325	nf_reset(skb);
	326	}
	327
d19d56dd ED	328	/**
	329	* skb_tunnel_rx - prepare skb for rx reinsert
	330	* @skb: buffer
	331	* @dev: tunnel device
	332	*
	333	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	334	* so make some cleanups, and perform accounting.
290b895e	335	* Note: this accounting is not SMP safe.
d19d56dd ED	336	*/
	337	static inline void skb_tunnel_rx(struct sk_buff skb, struct net_device dev)
	338	{
d19d56dd ED	339	/* TODO : stats should be SMP safe */
	340	dev->stats.rx_packets++;
	341	dev->stats.rx_bytes += skb->len;
290b895e	342	__skb_tunnel_rx(skb, dev);
d19d56dd ED	343	}
d19d56dd ED	344
1da177e4 LT	345	/* Children define the path of the packet through the
	346	* Linux networking. Thus, destinations are stackable.
	347	*/
	348
8764ab2c	349	static inline struct dst_entry skb_dst_pop(struct sk_buff skb)
1da177e4	350	{
8764ab2c	351	struct dst_entry *child = skb_dst(skb)->child;
1da177e4	352
8764ab2c	353	skb_dst_drop(skb);
1da177e4 LT	354	return child;
	355	}
	356
352e512c	357	extern int dst_discard(struct sk_buff *skb);
1da177e4 LT	358	extern void * dst_alloc(struct dst_ops * ops);
	359	extern void __dst_free(struct dst_entry * dst);
	360	extern struct dst_entry dst_destroy(struct dst_entry dst);
	361
	362	static inline void dst_free(struct dst_entry * dst)
	363	{
	364	if (dst->obsolete > 1)
	365	return;
	366	if (!atomic_read(&dst->__refcnt)) {
	367	dst = dst_destroy(dst);
	368	if (!dst)
	369	return;
	370	}
	371	__dst_free(dst);
	372	}
	373
	374	static inline void dst_rcu_free(struct rcu_head *head)
	375	{
	376	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
	377	dst_free(dst);
	378	}
	379
	380	static inline void dst_confirm(struct dst_entry *dst)
	381	{
	382	if (dst)
	383	neigh_confirm(dst->neighbour);
	384	}
	385
1da177e4 LT	386	static inline void dst_link_failure(struct sk_buff *skb)
1da177e4 LT	387	{
adf30907	388	struct dst_entry *dst = skb_dst(skb);
1da177e4 LT	389	if (dst && dst->ops && dst->ops->link_failure)
	390	dst->ops->link_failure(skb);
	391	}
	392
	393	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
	394	{
	395	unsigned long expires = jiffies + timeout;
	396
	397	if (expires == 0)
	398	expires = 1;
	399
	400	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
	401	dst->expires = expires;
	402	}
	403
	404	/* Output packet to network from transport. */
	405	static inline int dst_output(struct sk_buff *skb)
	406	{
adf30907	407	return skb_dst(skb)->output(skb);
1da177e4 LT	408	}
	409
	410	/* Input packet from network to transport. */
	411	static inline int dst_input(struct sk_buff *skb)
	412	{
adf30907	413	return skb_dst(skb)->input(skb);
1da177e4 LT	414	}
	415
	416	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	417	{
	418	if (dst->obsolete)
	419	dst = dst->ops->check(dst, cookie);
	420	return dst;
	421	}
	422
	423	extern void dst_init(void);
	424
815f4e57 HX	425	/* Flags for xfrm_lookup flags argument. */
	426	enum {
	427	XFRM_LOOKUP_WAIT = 1 << 0,
8b7817f3	428	XFRM_LOOKUP_ICMP = 1 << 1,
815f4e57 HX	429	};
815f4e57 HX	430
1da177e4 LT	431	struct flowi;
1da177e4 LT	432	#ifndef CONFIG_XFRM
52479b62 AD	433	static inline int xfrm_lookup(struct net net, struct dst_entry *dst_p,
52479b62 AD	434	struct flowi fl, struct sock sk, int flags)
1da177e4 LT	435	{
	436	return 0;
	437	}
52479b62 AD	438	static inline int __xfrm_lookup(struct net net, struct dst_entry *dst_p,
52479b62 AD	439	struct flowi fl, struct sock sk, int flags)
14e50e57 DM	440	{
	441	return 0;
	442	}
1da177e4	443	#else
52479b62 AD	444	extern int xfrm_lookup(struct net net, struct dst_entry *dst_p,
	445	struct flowi fl, struct sock sk, int flags);
	446	extern int __xfrm_lookup(struct net net, struct dst_entry *dst_p,
	447	struct flowi fl, struct sock sk, int flags);
1da177e4 LT	448	#endif
	449	#endif
	450
	451	#endif /* _NET_DST_H */