[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>

#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;
#ifdef CONFIG_XFRM
	struct xfrm_state	*xfrm;
#else
	void			*__pad1;
#endif
	int			(*input)(struct sk_buff*);
	int			(*output)(struct sk_buff*);

	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

	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[2];
#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;
	union {
		struct dst_entry	*next;
		struct rtable __rcu	*rt_next;
		struct rt6_info		*rt6_next;
		struct dn_route __rcu	*dn_next;
	};
};

static inline struct neighbour *dst_get_neighbour(struct dst_entry *dst)
{
	return dst->_neighbour;
}

static inline void dst_set_neighbour(struct dst_entry *dst, struct neighbour *neigh)
{
	dst->_neighbour = neigh;
}

extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
extern const u32 dst_default_metrics[RTAX_MAX];

#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;

	BUG_ON(!p);

	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);
	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 = dst_clone(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, struct net_device *dev,
		       int initial_ref, int initial_obsolete, int flags);
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) {
		struct neighbour *n = dst_get_neighbour(dst);
		neigh_confirm(n);
	}
}

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_ICMP = 1 << 0,
};

struct flowi;
#ifndef CONFIG_XFRM
static inline struct dst_entry *xfrm_lookup(struct net *net,
					    struct dst_entry *dst_orig,
					    const struct flowi *fl, struct sock *sk,
					    int flags)
{
	return dst_orig;
} 
#else
extern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
				     const struct flowi *fl, struct sock *sk,
				     int flags);
#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
1da177e4 LT	19	#define DST_GC_MIN (HZ/10)
	20	#define DST_GC_INC (HZ/2)
	21	#define DST_GC_MAX (120*HZ)
	22
	23	/* Each dst_entry has reference count and sits in some parent list(s).
	24	* When it is removed from parent list, it is "freed" (dst_free).
	25	* After this it enters dead state (dst->obsolete > 0) and if its refcnt
	26	* is zero, it can be destroyed immediately, otherwise it is added
	27	* to gc list and garbage collector periodically checks the refcnt.
	28	*/
	29
	30	struct sk_buff;
	31
fd2c3ef7	32	struct dst_entry {
1e19e02c	33	struct rcu_head rcu_head;
1da177e4 LT	34	struct dst_entry *child;
1da177e4 LT	35	struct net_device *dev;
62fa8a84 DM	36	struct dst_ops *ops;
62fa8a84 DM	37	unsigned long _metrics;
1da177e4	38	unsigned long expires;
f1dd9c37	39	struct dst_entry *path;
69cce1d1	40	struct neighbour *_neighbour;
def8b4fa	41	#ifdef CONFIG_XFRM
1da177e4	42	struct xfrm_state *xfrm;
5635c10d ED	43	#else
5635c10d ED	44	void *__pad1;
def8b4fa	45	#endif
1da177e4 LT	46	int (input)(struct sk_buff);
	47	int (output)(struct sk_buff);
	48
f6b72b62 DM	49	int flags;
	50	#define DST_HOST 0x0001
	51	#define DST_NOXFRM 0x0002
	52	#define DST_NOPOLICY 0x0004
	53	#define DST_NOHASH 0x0008
	54	#define DST_NOCACHE 0x0010
	55	#define DST_NOCOUNT 0x0020
	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
f6b72b62	72	long __pad_to_align_refcnt[2];
5635c10d	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;
1e19e02c	81	union {
fc766e4c ED	82	struct dst_entry *next;
	83	struct rtable __rcu *rt_next;
	84	struct rt6_info *rt6_next;
	85	struct dn_route __rcu *dn_next;
1e19e02c	86	};
1da177e4 LT	87	};
1da177e4 LT	88
69cce1d1 DM	89	static inline struct neighbour dst_get_neighbour(struct dst_entry dst)
	90	{
	91	return dst->_neighbour;
	92	}
	93
	94	static inline void dst_set_neighbour(struct dst_entry dst, struct neighbour neigh)
	95	{
	96	dst->_neighbour = neigh;
	97	}
	98
62fa8a84	99	extern u32 dst_cow_metrics_generic(struct dst_entry dst, unsigned long old);
725d1e1b	100	extern const u32 dst_default_metrics[RTAX_MAX];
62fa8a84 DM	101
	102	#define DST_METRICS_READ_ONLY 0x1UL
	103	#define __DST_METRICS_PTR(Y) \
	104	((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
	105	#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
	106
	107	static inline bool dst_metrics_read_only(const struct dst_entry *dst)
	108	{
	109	return dst->_metrics & DST_METRICS_READ_ONLY;
	110	}
	111
	112	extern void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
	113
	114	static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
	115	{
	116	unsigned long val = dst->_metrics;
	117	if (!(val & DST_METRICS_READ_ONLY))
	118	__dst_destroy_metrics_generic(dst, val);
	119	}
	120
	121	static inline u32 dst_metrics_write_ptr(struct dst_entry dst)
	122	{
	123	unsigned long p = dst->_metrics;
	124
1f37070d SH	125	BUG_ON(!p);
1f37070d SH	126
62fa8a84 DM	127	if (p & DST_METRICS_READ_ONLY)
	128	return dst->ops->cow_metrics(dst, p);
	129	return __DST_METRICS_PTR(p);
	130	}
	131
	132	/* This may only be invoked before the entry has reached global
	133	* visibility.
	134	*/
	135	static inline void dst_init_metrics(struct dst_entry *dst,
	136	const u32 *src_metrics,
	137	bool read_only)
	138	{
	139	dst->_metrics = ((unsigned long) src_metrics) \|
	140	(read_only ? DST_METRICS_READ_ONLY : 0);
	141	}
	142
	143	static inline void dst_copy_metrics(struct dst_entry dest, const struct dst_entry src)
	144	{
	145	u32 *dst_metrics = dst_metrics_write_ptr(dest);
	146
	147	if (dst_metrics) {
	148	u32 *src_metrics = DST_METRICS_PTR(src);
	149
	150	memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
	151	}
	152	}
	153
	154	static inline u32 dst_metrics_ptr(struct dst_entry dst)
	155	{
	156	return DST_METRICS_PTR(dst);
	157	}
	158
1da177e4	159	static inline u32
5170ae82	160	dst_metric_raw(const struct dst_entry *dst, const int metric)
1da177e4	161	{
62fa8a84 DM	162	u32 *p = DST_METRICS_PTR(dst);
	163
	164	return p[metric-1];
defb3519 DM	165	}
defb3519 DM	166
5170ae82 DM	167	static inline u32
	168	dst_metric(const struct dst_entry *dst, const int metric)
	169	{
0dbaee3b	170	WARN_ON_ONCE(metric == RTAX_HOPLIMIT \|\|
d33e4553 DM	171	metric == RTAX_ADVMSS \|\|
d33e4553 DM	172	metric == RTAX_MTU);
5170ae82 DM	173	return dst_metric_raw(dst, metric);
	174	}
	175
0dbaee3b DM	176	static inline u32
	177	dst_metric_advmss(const struct dst_entry *dst)
	178	{
	179	u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
	180
	181	if (!advmss)
	182	advmss = dst->ops->default_advmss(dst);
	183
	184	return advmss;
	185	}
	186
defb3519 DM	187	static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
defb3519 DM	188	{
62fa8a84	189	u32 *p = dst_metrics_write_ptr(dst);
defb3519	190
62fa8a84 DM	191	if (p)
62fa8a84 DM	192	p[metric-1] = val;
1da177e4 LT	193	}
1da177e4 LT	194
0c3adfb8 GBY	195	static inline u32
	196	dst_feature(const struct dst_entry *dst, u32 feature)
	197	{
bb5b7c11	198	return dst_metric(dst, RTAX_FEATURES) & feature;
0c3adfb8 GBY	199	}
0c3adfb8 GBY	200
1da177e4 LT	201	static inline u32 dst_mtu(const struct dst_entry *dst)
1da177e4 LT	202	{
d33e4553 DM	203	u32 mtu = dst_metric_raw(dst, RTAX_MTU);
	204
	205	if (!mtu)
	206	mtu = dst->ops->default_mtu(dst);
	207
1da177e4 LT	208	return mtu;
	209	}
	210
c1e20f7c SH	211	/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
	212	static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
	213	{
	214	return msecs_to_jiffies(dst_metric(dst, metric));
	215	}
	216
	217	static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
	218	unsigned long rtt)
	219	{
defb3519	220	dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
c1e20f7c SH	221	}
c1e20f7c SH	222
1da177e4 LT	223	static inline u32
	224	dst_allfrag(const struct dst_entry *dst)
	225	{
0c3adfb8	226	int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
1da177e4 LT	227	return ret;
	228	}
	229
	230	static inline int
d33e4553	231	dst_metric_locked(const struct dst_entry *dst, int metric)
1da177e4 LT	232	{
	233	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	234	}
	235
	236	static inline void dst_hold(struct dst_entry * dst)
	237	{
5635c10d ED	238	/*
	239	* If your kernel compilation stops here, please check
	240	* __pad_to_align_refcnt declaration in struct dst_entry
	241	*/
	242	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
1da177e4 LT	243	atomic_inc(&dst->__refcnt);
	244	}
	245
03f49f34 PE	246	static inline void dst_use(struct dst_entry *dst, unsigned long time)
	247	{
	248	dst_hold(dst);
	249	dst->__use++;
	250	dst->lastuse = time;
	251	}
	252
7fee226a ED	253	static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
	254	{
	255	dst->__use++;
	256	dst->lastuse = time;
	257	}
	258
1da177e4 LT	259	static inline
	260	struct dst_entry * dst_clone(struct dst_entry * dst)
	261	{
	262	if (dst)
	263	atomic_inc(&dst->__refcnt);
	264	return dst;
	265	}
	266
8d330868	267	extern void dst_release(struct dst_entry *dst);
7fee226a ED	268
	269	static inline void refdst_drop(unsigned long refdst)
	270	{
	271	if (!(refdst & SKB_DST_NOREF))
	272	dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
	273	}
	274
	275	/**
	276	* skb_dst_drop - drops skb dst
	277	* @skb: buffer
	278	*
	279	* Drops dst reference count if a reference was taken.
	280	*/
adf30907 ED	281	static inline void skb_dst_drop(struct sk_buff *skb)
adf30907 ED	282	{
7fee226a ED	283	if (skb->_skb_refdst) {
	284	refdst_drop(skb->_skb_refdst);
	285	skb->_skb_refdst = 0UL;
	286	}
	287	}
	288
	289	static inline void skb_dst_copy(struct sk_buff nskb, const struct sk_buff oskb)
	290	{
	291	nskb->_skb_refdst = oskb->_skb_refdst;
	292	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
	293	dst_clone(skb_dst(nskb));
	294	}
	295
	296	/**
	297	* skb_dst_force - makes sure skb dst is refcounted
	298	* @skb: buffer
	299	*
	300	* If dst is not yet refcounted, let's do it
	301	*/
	302	static inline void skb_dst_force(struct sk_buff *skb)
	303	{
	304	if (skb_dst_is_noref(skb)) {
	305	WARN_ON(!rcu_read_lock_held());
	306	skb->_skb_refdst &= ~SKB_DST_NOREF;
	307	dst_clone(skb_dst(skb));
	308	}
adf30907	309	}
1da177e4	310
d19d56dd	311
290b895e ED	312	/**
	313	* __skb_tunnel_rx - prepare skb for rx reinsert
	314	* @skb: buffer
	315	* @dev: tunnel device
	316	*
	317	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	318	* so make some cleanups. (no accounting done)
	319	*/
	320	static inline void __skb_tunnel_rx(struct sk_buff skb, struct net_device dev)
	321	{
	322	skb->dev = dev;
	323	skb->rxhash = 0;
	324	skb_set_queue_mapping(skb, 0);
	325	skb_dst_drop(skb);
	326	nf_reset(skb);
	327	}
	328
d19d56dd ED	329	/**
	330	* skb_tunnel_rx - prepare skb for rx reinsert
	331	* @skb: buffer
	332	* @dev: tunnel device
	333	*
	334	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	335	* so make some cleanups, and perform accounting.
290b895e	336	* Note: this accounting is not SMP safe.
d19d56dd ED	337	*/
	338	static inline void skb_tunnel_rx(struct sk_buff skb, struct net_device dev)
	339	{
d19d56dd ED	340	/* TODO : stats should be SMP safe */
	341	dev->stats.rx_packets++;
	342	dev->stats.rx_bytes += skb->len;
290b895e	343	__skb_tunnel_rx(skb, dev);
d19d56dd ED	344	}
d19d56dd ED	345
1da177e4 LT	346	/* Children define the path of the packet through the
	347	* Linux networking. Thus, destinations are stackable.
	348	*/
	349
8764ab2c	350	static inline struct dst_entry skb_dst_pop(struct sk_buff skb)
1da177e4	351	{
e433430a	352	struct dst_entry *child = dst_clone(skb_dst(skb)->child);
1da177e4	353
8764ab2c	354	skb_dst_drop(skb);
1da177e4 LT	355	return child;
	356	}
	357
352e512c	358	extern int dst_discard(struct sk_buff *skb);
5c1e6aa3 DM	359	extern void dst_alloc(struct dst_ops ops, struct net_device *dev,
5c1e6aa3 DM	360	int initial_ref, int initial_obsolete, int flags);
1da177e4 LT	361	extern void __dst_free(struct dst_entry * dst);
	362	extern struct dst_entry dst_destroy(struct dst_entry dst);
	363
	364	static inline void dst_free(struct dst_entry * dst)
	365	{
	366	if (dst->obsolete > 1)
	367	return;
	368	if (!atomic_read(&dst->__refcnt)) {
	369	dst = dst_destroy(dst);
	370	if (!dst)
	371	return;
	372	}
	373	__dst_free(dst);
	374	}
	375
	376	static inline void dst_rcu_free(struct rcu_head *head)
	377	{
	378	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
	379	dst_free(dst);
	380	}
	381
	382	static inline void dst_confirm(struct dst_entry *dst)
	383	{
69cce1d1 DM	384	if (dst) {
	385	struct neighbour *n = dst_get_neighbour(dst);
	386	neigh_confirm(n);
	387	}
1da177e4 LT	388	}
1da177e4 LT	389
1da177e4 LT	390	static inline void dst_link_failure(struct sk_buff *skb)
1da177e4 LT	391	{
adf30907	392	struct dst_entry *dst = skb_dst(skb);
1da177e4 LT	393	if (dst && dst->ops && dst->ops->link_failure)
	394	dst->ops->link_failure(skb);
	395	}
	396
	397	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
	398	{
	399	unsigned long expires = jiffies + timeout;
	400
	401	if (expires == 0)
	402	expires = 1;
	403
	404	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
	405	dst->expires = expires;
	406	}
	407
	408	/* Output packet to network from transport. */
	409	static inline int dst_output(struct sk_buff *skb)
	410	{
adf30907	411	return skb_dst(skb)->output(skb);
1da177e4 LT	412	}
	413
	414	/* Input packet from network to transport. */
	415	static inline int dst_input(struct sk_buff *skb)
	416	{
adf30907	417	return skb_dst(skb)->input(skb);
1da177e4 LT	418	}
	419
	420	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	421	{
	422	if (dst->obsolete)
	423	dst = dst->ops->check(dst, cookie);
	424	return dst;
	425	}
	426
	427	extern void dst_init(void);
	428
815f4e57 HX	429	/* Flags for xfrm_lookup flags argument. */
815f4e57 HX	430	enum {
80c0bc9e	431	XFRM_LOOKUP_ICMP = 1 << 0,
815f4e57 HX	432	};
815f4e57 HX	433
1da177e4 LT	434	struct flowi;
1da177e4 LT	435	#ifndef CONFIG_XFRM
452edd59 DM	436	static inline struct dst_entry xfrm_lookup(struct net net,
	437	struct dst_entry *dst_orig,
	438	const struct flowi fl, struct sock sk,
	439	int flags)
1da177e4	440	{
452edd59	441	return dst_orig;
1da177e4 LT	442	}
1da177e4 LT	443	#else
452edd59 DM	444	extern struct dst_entry xfrm_lookup(struct net net, struct dst_entry *dst_orig,
	445	const struct flowi fl, struct sock sk,
	446	int flags);
1da177e4	447	#endif
1da177e4 LT	448
1da177e4 LT	449	#endif /* _NET_DST_H */