[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/bug.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 dst_entry	*from;
#ifdef CONFIG_XFRM
	struct xfrm_state	*xfrm;
#else
	void			*__pad1;
#endif
	int			(*input)(struct sk_buff *);
	int			(*output)(struct sock *sk, struct sk_buff *skb);

	unsigned short		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
#define DST_FAKE_RTABLE		0x0040
#define DST_XFRM_TUNNEL		0x0080
#define DST_XFRM_QUEUE		0x0100

	unsigned short		pending_confirm;

	short			error;

	/* A non-zero value of dst->obsolete forces by-hand validation
	 * of the route entry.  Positive values are set by the generic
	 * dst layer to indicate that the entry has been forcefully
	 * destroyed.
	 *
	 * Negative values are used by the implementation layer code to
	 * force invocation of the dst_ops->check() method.
	 */
	short			obsolete;
#define DST_OBSOLETE_NONE	0
#define DST_OBSOLETE_DEAD	2
#define DST_OBSOLETE_FORCE_CHK	-1
#define DST_OBSOLETE_KILL	-2
	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;
	};
};

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

#define DST_METRICS_READ_ONLY		0x1UL
#define DST_METRICS_FORCE_OVERWRITE	0x2UL
#define DST_METRICS_FLAGS		0x3UL
#define __DST_METRICS_PTR(Y)	\
	((u32 *)((Y) & ~DST_METRICS_FLAGS))
#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;
}

static inline void dst_metrics_set_force_overwrite(struct dst_entry *dst)
{
	dst->_metrics |= DST_METRICS_FORCE_OVERWRITE;
}

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)
{
	return dst->ops->mtu(dst);
}

/* 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 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;
}

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
 *	@net: netns for packet i/o
 *
 *	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,
				   struct net *net)
{
	skb->dev = dev;

	/*
	 * Clear hash so that we can recalulate the hash for the
	 * encapsulated packet, unless we have already determine the hash
	 * over the L4 4-tuple.
	 */
	skb_clear_hash_if_not_l4(skb);
	skb_set_queue_mapping(skb, 0);
	skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
}

/**
 *	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,
				 struct net *net)
{
	/* TODO : stats should be SMP safe */
	dev->stats.rx_packets++;
	dev->stats.rx_bytes += skb->len;
	__skb_tunnel_rx(skb, dev, net);
}

/* 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;
}

int dst_discard_sk(struct sock *sk, struct sk_buff *skb);
static inline int dst_discard(struct sk_buff *skb)
{
	return dst_discard_sk(skb->sk, skb);
}
void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
		int initial_obsolete, unsigned short flags);
void __dst_free(struct dst_entry *dst);
struct dst_entry *dst_destroy(struct dst_entry *dst);

static inline void dst_free(struct dst_entry *dst)
{
	if (dst->obsolete > 0)
		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)
{
	dst->pending_confirm = 1;
}

static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
				   struct sk_buff *skb)
{
	const struct hh_cache *hh;

	if (dst->pending_confirm) {
		unsigned long now = jiffies;

		dst->pending_confirm = 0;
		/* avoid dirtying neighbour */
		if (n->confirmed != now)
			n->confirmed = now;
	}

	hh = &n->hh;
	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
		return neigh_hh_output(hh, skb);
	else
		return n->output(n, skb);
}

static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
{
	struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
	return IS_ERR(n) ? NULL : n;
}

static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
						     struct sk_buff *skb)
{
	struct neighbour *n =  dst->ops->neigh_lookup(dst, skb, NULL);
	return IS_ERR(n) ? NULL : 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_sk(struct sock *sk, struct sk_buff *skb)
{
	return skb_dst(skb)->output(sk, skb);
}
static inline int dst_output(struct sk_buff *skb)
{
	return dst_output_sk(skb->sk, 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;
}

void dst_init(void);

/* Flags for xfrm_lookup flags argument. */
enum {
	XFRM_LOOKUP_ICMP = 1 << 0,
	XFRM_LOOKUP_QUEUE = 1 << 1,
	XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
};

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;
}

static inline struct dst_entry *xfrm_lookup_route(struct net *net,
						  struct dst_entry *dst_orig,
						  const struct flowi *fl,
						  struct sock *sk,
						  int flags)
{
	return dst_orig;
}

static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
{
	return NULL;
}

#else
struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
			      const struct flowi *fl, struct sock *sk,
			      int flags);

struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
				    const struct flowi *fl, struct sock *sk,
				    int flags);

/* skb attached with this dst needs transformation if dst->xfrm is valid */
static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
{
	return dst->xfrm;
}
#endif

#endif /* _NET_DST_H */
Commit	Line	Data
	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
	11	#include <net/dst_ops.h>
	12	#include <linux/netdevice.h>
	13	#include <linux/rtnetlink.h>
	14	#include <linux/rcupdate.h>
	15	#include <linux/bug.h>
	16	#include <linux/jiffies.h>
	17	#include <net/neighbour.h>
	18	#include <asm/processor.h>
	19
	20	#define DST_GC_MIN (HZ/10)
	21	#define DST_GC_INC (HZ/2)
	22	#define DST_GC_MAX (120*HZ)
	23
	24	/* Each dst_entry has reference count and sits in some parent list(s).
	25	* When it is removed from parent list, it is "freed" (dst_free).
	26	* After this it enters dead state (dst->obsolete > 0) and if its refcnt
	27	* is zero, it can be destroyed immediately, otherwise it is added
	28	* to gc list and garbage collector periodically checks the refcnt.
	29	*/
	30
	31	struct sk_buff;
	32
	33	struct dst_entry {
	34	struct rcu_head rcu_head;
	35	struct dst_entry *child;
	36	struct net_device *dev;
	37	struct dst_ops *ops;
	38	unsigned long _metrics;
	39	unsigned long expires;
	40	struct dst_entry *path;
	41	struct dst_entry *from;
	42	#ifdef CONFIG_XFRM
	43	struct xfrm_state *xfrm;
	44	#else
	45	void *__pad1;
	46	#endif
	47	int (input)(struct sk_buff );
	48	int (output)(struct sock sk, struct sk_buff *skb);
	49
	50	unsigned short flags;
	51	#define DST_HOST 0x0001
	52	#define DST_NOXFRM 0x0002
	53	#define DST_NOPOLICY 0x0004
	54	#define DST_NOHASH 0x0008
	55	#define DST_NOCACHE 0x0010
	56	#define DST_NOCOUNT 0x0020
	57	#define DST_FAKE_RTABLE 0x0040
	58	#define DST_XFRM_TUNNEL 0x0080
	59	#define DST_XFRM_QUEUE 0x0100
	60
	61	unsigned short pending_confirm;
	62
	63	short error;
	64
	65	/* A non-zero value of dst->obsolete forces by-hand validation
	66	* of the route entry. Positive values are set by the generic
	67	* dst layer to indicate that the entry has been forcefully
	68	* destroyed.
	69	*
	70	* Negative values are used by the implementation layer code to
	71	* force invocation of the dst_ops->check() method.
	72	*/
	73	short obsolete;
	74	#define DST_OBSOLETE_NONE 0
	75	#define DST_OBSOLETE_DEAD 2
	76	#define DST_OBSOLETE_FORCE_CHK -1
	77	#define DST_OBSOLETE_KILL -2
	78	unsigned short header_len; /* more space at head required */
	79	unsigned short trailer_len; /* space to reserve at tail */
	80	#ifdef CONFIG_IP_ROUTE_CLASSID
	81	__u32 tclassid;
	82	#else
	83	__u32 __pad2;
	84	#endif
	85
	86	/*
	87	* Align __refcnt to a 64 bytes alignment
	88	* (L1_CACHE_SIZE would be too much)
	89	*/
	90	#ifdef CONFIG_64BIT
	91	long __pad_to_align_refcnt[2];
	92	#endif
	93	/*
	94	* __refcnt wants to be on a different cache line from
	95	* input/output/ops or performance tanks badly
	96	*/
	97	atomic_t __refcnt; /* client references */
	98	int __use;
	99	unsigned long lastuse;
	100	union {
	101	struct dst_entry *next;
	102	struct rtable __rcu *rt_next;
	103	struct rt6_info *rt6_next;
	104	struct dn_route __rcu *dn_next;
	105	};
	106	};
	107
	108	u32 dst_cow_metrics_generic(struct dst_entry dst, unsigned long old);
	109	extern const u32 dst_default_metrics[];
	110
	111	#define DST_METRICS_READ_ONLY 0x1UL
	112	#define DST_METRICS_FORCE_OVERWRITE 0x2UL
	113	#define DST_METRICS_FLAGS 0x3UL
	114	#define __DST_METRICS_PTR(Y) \
	115	((u32 *)((Y) & ~DST_METRICS_FLAGS))
	116	#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
	117
	118	static inline bool dst_metrics_read_only(const struct dst_entry *dst)
	119	{
	120	return dst->_metrics & DST_METRICS_READ_ONLY;
	121	}
	122
	123	static inline void dst_metrics_set_force_overwrite(struct dst_entry *dst)
	124	{
	125	dst->_metrics \|= DST_METRICS_FORCE_OVERWRITE;
	126	}
	127
	128	void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
	129
	130	static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
	131	{
	132	unsigned long val = dst->_metrics;
	133	if (!(val & DST_METRICS_READ_ONLY))
	134	__dst_destroy_metrics_generic(dst, val);
	135	}
	136
	137	static inline u32 dst_metrics_write_ptr(struct dst_entry dst)
	138	{
	139	unsigned long p = dst->_metrics;
	140
	141	BUG_ON(!p);
	142
	143	if (p & DST_METRICS_READ_ONLY)
	144	return dst->ops->cow_metrics(dst, p);
	145	return __DST_METRICS_PTR(p);
	146	}
	147
	148	/* This may only be invoked before the entry has reached global
	149	* visibility.
	150	*/
	151	static inline void dst_init_metrics(struct dst_entry *dst,
	152	const u32 *src_metrics,
	153	bool read_only)
	154	{
	155	dst->_metrics = ((unsigned long) src_metrics) \|
	156	(read_only ? DST_METRICS_READ_ONLY : 0);
	157	}
	158
	159	static inline void dst_copy_metrics(struct dst_entry dest, const struct dst_entry src)
	160	{
	161	u32 *dst_metrics = dst_metrics_write_ptr(dest);
	162
	163	if (dst_metrics) {
	164	u32 *src_metrics = DST_METRICS_PTR(src);
	165
	166	memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
	167	}
	168	}
	169
	170	static inline u32 dst_metrics_ptr(struct dst_entry dst)
	171	{
	172	return DST_METRICS_PTR(dst);
	173	}
	174
	175	static inline u32
	176	dst_metric_raw(const struct dst_entry *dst, const int metric)
	177	{
	178	u32 *p = DST_METRICS_PTR(dst);
	179
	180	return p[metric-1];
	181	}
	182
	183	static inline u32
	184	dst_metric(const struct dst_entry *dst, const int metric)
	185	{
	186	WARN_ON_ONCE(metric == RTAX_HOPLIMIT \|\|
	187	metric == RTAX_ADVMSS \|\|
	188	metric == RTAX_MTU);
	189	return dst_metric_raw(dst, metric);
	190	}
	191
	192	static inline u32
	193	dst_metric_advmss(const struct dst_entry *dst)
	194	{
	195	u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
	196
	197	if (!advmss)
	198	advmss = dst->ops->default_advmss(dst);
	199
	200	return advmss;
	201	}
	202
	203	static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
	204	{
	205	u32 *p = dst_metrics_write_ptr(dst);
	206
	207	if (p)
	208	p[metric-1] = val;
	209	}
	210
	211	static inline u32
	212	dst_feature(const struct dst_entry *dst, u32 feature)
	213	{
	214	return dst_metric(dst, RTAX_FEATURES) & feature;
	215	}
	216
	217	static inline u32 dst_mtu(const struct dst_entry *dst)
	218	{
	219	return dst->ops->mtu(dst);
	220	}
	221
	222	/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
	223	static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
	224	{
	225	return msecs_to_jiffies(dst_metric(dst, metric));
	226	}
	227
	228	static inline u32
	229	dst_allfrag(const struct dst_entry *dst)
	230	{
	231	int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
	232	return ret;
	233	}
	234
	235	static inline int
	236	dst_metric_locked(const struct dst_entry *dst, int metric)
	237	{
	238	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	239	}
	240
	241	static inline void dst_hold(struct dst_entry *dst)
	242	{
	243	/*
	244	* If your kernel compilation stops here, please check
	245	* __pad_to_align_refcnt declaration in struct dst_entry
	246	*/
	247	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
	248	atomic_inc(&dst->__refcnt);
	249	}
	250
	251	static inline void dst_use(struct dst_entry *dst, unsigned long time)
	252	{
	253	dst_hold(dst);
	254	dst->__use++;
	255	dst->lastuse = time;
	256	}
	257
	258	static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
	259	{
	260	dst->__use++;
	261	dst->lastuse = time;
	262	}
	263
	264	static inline struct dst_entry dst_clone(struct dst_entry dst)
	265	{
	266	if (dst)
	267	atomic_inc(&dst->__refcnt);
	268	return dst;
	269	}
	270
	271	void dst_release(struct dst_entry *dst);
	272
	273	static inline void refdst_drop(unsigned long refdst)
	274	{
	275	if (!(refdst & SKB_DST_NOREF))
	276	dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
	277	}
	278
	279	/**
	280	* skb_dst_drop - drops skb dst
	281	* @skb: buffer
	282	*
	283	* Drops dst reference count if a reference was taken.
	284	*/
	285	static inline void skb_dst_drop(struct sk_buff *skb)
	286	{
	287	if (skb->_skb_refdst) {
	288	refdst_drop(skb->_skb_refdst);
	289	skb->_skb_refdst = 0UL;
	290	}
	291	}
	292
	293	static inline void skb_dst_copy(struct sk_buff nskb, const struct sk_buff oskb)
	294	{
	295	nskb->_skb_refdst = oskb->_skb_refdst;
	296	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
	297	dst_clone(skb_dst(nskb));
	298	}
	299
	300	/**
	301	* skb_dst_force - makes sure skb dst is refcounted
	302	* @skb: buffer
	303	*
	304	* If dst is not yet refcounted, let's do it
	305	*/
	306	static inline void skb_dst_force(struct sk_buff *skb)
	307	{
	308	if (skb_dst_is_noref(skb)) {
	309	WARN_ON(!rcu_read_lock_held());
	310	skb->_skb_refdst &= ~SKB_DST_NOREF;
	311	dst_clone(skb_dst(skb));
	312	}
	313	}
	314
	315
	316	/**
	317	* __skb_tunnel_rx - prepare skb for rx reinsert
	318	* @skb: buffer
	319	* @dev: tunnel device
	320	* @net: netns for packet i/o
	321	*
	322	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	323	* so make some cleanups. (no accounting done)
	324	*/
	325	static inline void __skb_tunnel_rx(struct sk_buff skb, struct net_device dev,
	326	struct net *net)
	327	{
	328	skb->dev = dev;
	329
	330	/*
	331	* Clear hash so that we can recalulate the hash for the
	332	* encapsulated packet, unless we have already determine the hash
	333	* over the L4 4-tuple.
	334	*/
	335	skb_clear_hash_if_not_l4(skb);
	336	skb_set_queue_mapping(skb, 0);
	337	skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
	338	}
	339
	340	/**
	341	* skb_tunnel_rx - prepare skb for rx reinsert
	342	* @skb: buffer
	343	* @dev: tunnel device
	344	*
	345	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	346	* so make some cleanups, and perform accounting.
	347	* Note: this accounting is not SMP safe.
	348	*/
	349	static inline void skb_tunnel_rx(struct sk_buff skb, struct net_device dev,
	350	struct net *net)
	351	{
	352	/* TODO : stats should be SMP safe */
	353	dev->stats.rx_packets++;
	354	dev->stats.rx_bytes += skb->len;
	355	__skb_tunnel_rx(skb, dev, net);
	356	}
	357
	358	/* Children define the path of the packet through the
	359	* Linux networking. Thus, destinations are stackable.
	360	*/
	361
	362	static inline struct dst_entry skb_dst_pop(struct sk_buff skb)
	363	{
	364	struct dst_entry *child = dst_clone(skb_dst(skb)->child);
	365
	366	skb_dst_drop(skb);
	367	return child;
	368	}
	369
	370	int dst_discard_sk(struct sock sk, struct sk_buff skb);
	371	static inline int dst_discard(struct sk_buff *skb)
	372	{
	373	return dst_discard_sk(skb->sk, skb);
	374	}
	375	void dst_alloc(struct dst_ops ops, struct net_device *dev, int initial_ref,
	376	int initial_obsolete, unsigned short flags);
	377	void __dst_free(struct dst_entry *dst);
	378	struct dst_entry dst_destroy(struct dst_entry dst);
	379
	380	static inline void dst_free(struct dst_entry *dst)
	381	{
	382	if (dst->obsolete > 0)
	383	return;
	384	if (!atomic_read(&dst->__refcnt)) {
	385	dst = dst_destroy(dst);
	386	if (!dst)
	387	return;
	388	}
	389	__dst_free(dst);
	390	}
	391
	392	static inline void dst_rcu_free(struct rcu_head *head)
	393	{
	394	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
	395	dst_free(dst);
	396	}
	397
	398	static inline void dst_confirm(struct dst_entry *dst)
	399	{
	400	dst->pending_confirm = 1;
	401	}
	402
	403	static inline int dst_neigh_output(struct dst_entry dst, struct neighbour n,
	404	struct sk_buff *skb)
	405	{
	406	const struct hh_cache *hh;
	407
	408	if (dst->pending_confirm) {
	409	unsigned long now = jiffies;
	410
	411	dst->pending_confirm = 0;
	412	/* avoid dirtying neighbour */
	413	if (n->confirmed != now)
	414	n->confirmed = now;
	415	}
	416
	417	hh = &n->hh;
	418	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
	419	return neigh_hh_output(hh, skb);
	420	else
	421	return n->output(n, skb);
	422	}
	423
	424	static inline struct neighbour dst_neigh_lookup(const struct dst_entry dst, const void *daddr)
	425	{
	426	struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
	427	return IS_ERR(n) ? NULL : n;
	428	}
	429
	430	static inline struct neighbour dst_neigh_lookup_skb(const struct dst_entry dst,
	431	struct sk_buff *skb)
	432	{
	433	struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
	434	return IS_ERR(n) ? NULL : n;
	435	}
	436
	437	static inline void dst_link_failure(struct sk_buff *skb)
	438	{
	439	struct dst_entry *dst = skb_dst(skb);
	440	if (dst && dst->ops && dst->ops->link_failure)
	441	dst->ops->link_failure(skb);
	442	}
	443
	444	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
	445	{
	446	unsigned long expires = jiffies + timeout;
	447
	448	if (expires == 0)
	449	expires = 1;
	450
	451	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
	452	dst->expires = expires;
	453	}
	454
	455	/* Output packet to network from transport. */
	456	static inline int dst_output_sk(struct sock sk, struct sk_buff skb)
	457	{
	458	return skb_dst(skb)->output(sk, skb);
	459	}
	460	static inline int dst_output(struct sk_buff *skb)
	461	{
	462	return dst_output_sk(skb->sk, skb);
	463	}
	464
	465	/* Input packet from network to transport. */
	466	static inline int dst_input(struct sk_buff *skb)
	467	{
	468	return skb_dst(skb)->input(skb);
	469	}
	470
	471	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	472	{
	473	if (dst->obsolete)
	474	dst = dst->ops->check(dst, cookie);
	475	return dst;
	476	}
	477
	478	void dst_init(void);
	479
	480	/* Flags for xfrm_lookup flags argument. */
	481	enum {
	482	XFRM_LOOKUP_ICMP = 1 << 0,
	483	XFRM_LOOKUP_QUEUE = 1 << 1,
	484	XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
	485	};
	486
	487	struct flowi;
	488	#ifndef CONFIG_XFRM
	489	static inline struct dst_entry xfrm_lookup(struct net net,
	490	struct dst_entry *dst_orig,
	491	const struct flowi fl, struct sock sk,
	492	int flags)
	493	{
	494	return dst_orig;
	495	}
	496
	497	static inline struct dst_entry xfrm_lookup_route(struct net net,
	498	struct dst_entry *dst_orig,
	499	const struct flowi *fl,
	500	struct sock *sk,
	501	int flags)
	502	{
	503	return dst_orig;
	504	}
	505
	506	static inline struct xfrm_state dst_xfrm(const struct dst_entry dst)
	507	{
	508	return NULL;
	509	}
	510
	511	#else
	512	struct dst_entry xfrm_lookup(struct net net, struct dst_entry *dst_orig,
	513	const struct flowi fl, struct sock sk,
	514	int flags);
	515
	516	struct dst_entry xfrm_lookup_route(struct net net, struct dst_entry *dst_orig,
	517	const struct flowi fl, struct sock sk,
	518	int flags);
	519
	520	/* skb attached with this dst needs transformation if dst->xfrm is valid */
	521	static inline struct xfrm_state dst_xfrm(const struct dst_entry dst)
	522	{
	523	return dst->xfrm;
	524	}
	525	#endif
	526
	527	#endif /* _NET_DST_H */