[mirror_ubuntu-eoan-kernel.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;
	union {
		unsigned long           expires;
		/* point to where the dst_entry copied from */
		struct dst_entry        *from;
	};
	struct dst_entry	*path;
	void			*__pad0;
#ifdef CONFIG_XFRM
	struct xfrm_state	*xfrm;
#else
	void			*__pad1;
#endif
	int			(*input)(struct sk_buff *);
	int			(*output)(struct sk_buff *);

	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_NOPEER		0x0040
#define DST_FAKE_RTABLE		0x0080
#define DST_XFRM_TUNNEL		0x0100
#define DST_XFRM_QUEUE		0x0200

	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;
	};
};

extern 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_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)
{
	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;
}

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;

	/*
	 * 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;
	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,
		       unsigned short 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 > 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)
{
	return dst->ops->neigh_lookup(dst, NULL, daddr);
}

static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
						     struct sk_buff *skb)
{
	return dst->ops->neigh_lookup(dst, skb, NULL);
}

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>
1da177e4 LT	14	#include <linux/rcupdate.h>
187f1882	15	#include <linux/bug.h>
1da177e4 LT	16	#include <linux/jiffies.h>
	17	#include <net/neighbour.h>
	18	#include <asm/processor.h>
	19
1da177e4 LT	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
fd2c3ef7	33	struct dst_entry {
1e19e02c	34	struct rcu_head rcu_head;
1da177e4 LT	35	struct dst_entry *child;
1da177e4 LT	36	struct net_device *dev;
62fa8a84 DM	37	struct dst_ops *ops;
62fa8a84 DM	38	unsigned long _metrics;
1716a961 G	39	union {
	40	unsigned long expires;
	41	/* point to where the dst_entry copied from */
	42	struct dst_entry *from;
	43	};
f1dd9c37	44	struct dst_entry *path;
36bdbcae	45	void *__pad0;
def8b4fa	46	#ifdef CONFIG_XFRM
1da177e4	47	struct xfrm_state *xfrm;
5635c10d ED	48	#else
5635c10d ED	49	void *__pad1;
def8b4fa	50	#endif
7f95e188 EZ	51	int (input)(struct sk_buff );
7f95e188 EZ	52	int (output)(struct sk_buff );
1da177e4	53
5110effe	54	unsigned short flags;
f6b72b62 DM	55	#define DST_HOST 0x0001
	56	#define DST_NOXFRM 0x0002
	57	#define DST_NOPOLICY 0x0004
	58	#define DST_NOHASH 0x0008
	59	#define DST_NOCACHE 0x0010
	60	#define DST_NOCOUNT 0x0020
e688a604	61	#define DST_NOPEER 0x0040
a881e963	62	#define DST_FAKE_RTABLE 0x0080
0c183379	63	#define DST_XFRM_TUNNEL 0x0100
a0073fe1	64	#define DST_XFRM_QUEUE 0x0200
f6b72b62	65
5110effe DM	66	unsigned short pending_confirm;
5110effe DM	67
62fa8a84	68	short error;
f5b0a874 DM	69
	70	/* A non-zero value of dst->obsolete forces by-hand validation
	71	* of the route entry. Positive values are set by the generic
	72	* dst layer to indicate that the entry has been forcefully
	73	* destroyed.
	74	*
	75	* Negative values are used by the implementation layer code to
	76	* force invocation of the dst_ops->check() method.
	77	*/
62fa8a84	78	short obsolete;
f5b0a874 DM	79	#define DST_OBSOLETE_NONE 0
	80	#define DST_OBSOLETE_DEAD 2
	81	#define DST_OBSOLETE_FORCE_CHK -1
ceb33206	82	#define DST_OBSOLETE_KILL -2
62fa8a84 DM	83	unsigned short header_len; /* more space at head required */
62fa8a84 DM	84	unsigned short trailer_len; /* space to reserve at tail */
c7066f70	85	#ifdef CONFIG_IP_ROUTE_CLASSID
f1dd9c37	86	__u32 tclassid;
5635c10d ED	87	#else
5635c10d ED	88	__u32 __pad2;
f1dd9c37 ZY	89	#endif
f1dd9c37 ZY	90
5635c10d ED	91	/*
	92	* Align __refcnt to a 64 bytes alignment
	93	* (L1_CACHE_SIZE would be too much)
	94	*/
	95	#ifdef CONFIG_64BIT
f6b72b62	96	long __pad_to_align_refcnt[2];
5635c10d	97	#endif
f1dd9c37 ZY	98	/*
	99	* __refcnt wants to be on a different cache line from
	100	* input/output/ops or performance tanks badly
	101	*/
1e19e02c ED	102	atomic_t __refcnt; /* client references */
1e19e02c ED	103	int __use;
f1dd9c37	104	unsigned long lastuse;
1e19e02c	105	union {
fc766e4c ED	106	struct dst_entry *next;
	107	struct rtable __rcu *rt_next;
	108	struct rt6_info *rt6_next;
	109	struct dn_route __rcu *dn_next;
1e19e02c	110	};
1da177e4 LT	111	};
1da177e4 LT	112
62fa8a84	113	extern u32 dst_cow_metrics_generic(struct dst_entry dst, unsigned long old);
a37e6e34	114	extern const u32 dst_default_metrics[];
62fa8a84 DM	115
	116	#define DST_METRICS_READ_ONLY 0x1UL
	117	#define __DST_METRICS_PTR(Y) \
	118	((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
	119	#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
	120
	121	static inline bool dst_metrics_read_only(const struct dst_entry *dst)
	122	{
	123	return dst->_metrics & DST_METRICS_READ_ONLY;
	124	}
	125
	126	extern void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
	127
	128	static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
	129	{
	130	unsigned long val = dst->_metrics;
	131	if (!(val & DST_METRICS_READ_ONLY))
	132	__dst_destroy_metrics_generic(dst, val);
	133	}
	134
	135	static inline u32 dst_metrics_write_ptr(struct dst_entry dst)
	136	{
	137	unsigned long p = dst->_metrics;
	138
1f37070d SH	139	BUG_ON(!p);
1f37070d SH	140
62fa8a84 DM	141	if (p & DST_METRICS_READ_ONLY)
	142	return dst->ops->cow_metrics(dst, p);
	143	return __DST_METRICS_PTR(p);
	144	}
	145
	146	/* This may only be invoked before the entry has reached global
	147	* visibility.
	148	*/
	149	static inline void dst_init_metrics(struct dst_entry *dst,
	150	const u32 *src_metrics,
	151	bool read_only)
	152	{
	153	dst->_metrics = ((unsigned long) src_metrics) \|
	154	(read_only ? DST_METRICS_READ_ONLY : 0);
	155	}
	156
	157	static inline void dst_copy_metrics(struct dst_entry dest, const struct dst_entry src)
	158	{
	159	u32 *dst_metrics = dst_metrics_write_ptr(dest);
	160
	161	if (dst_metrics) {
	162	u32 *src_metrics = DST_METRICS_PTR(src);
	163
	164	memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
	165	}
	166	}
	167
	168	static inline u32 dst_metrics_ptr(struct dst_entry dst)
	169	{
	170	return DST_METRICS_PTR(dst);
	171	}
	172
1da177e4	173	static inline u32
5170ae82	174	dst_metric_raw(const struct dst_entry *dst, const int metric)
1da177e4	175	{
62fa8a84 DM	176	u32 *p = DST_METRICS_PTR(dst);
	177
	178	return p[metric-1];
defb3519 DM	179	}
defb3519 DM	180
5170ae82 DM	181	static inline u32
	182	dst_metric(const struct dst_entry *dst, const int metric)
	183	{
0dbaee3b	184	WARN_ON_ONCE(metric == RTAX_HOPLIMIT \|\|
d33e4553 DM	185	metric == RTAX_ADVMSS \|\|
d33e4553 DM	186	metric == RTAX_MTU);
5170ae82 DM	187	return dst_metric_raw(dst, metric);
	188	}
	189
0dbaee3b DM	190	static inline u32
	191	dst_metric_advmss(const struct dst_entry *dst)
	192	{
	193	u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
	194
	195	if (!advmss)
	196	advmss = dst->ops->default_advmss(dst);
	197
	198	return advmss;
	199	}
	200
defb3519 DM	201	static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
defb3519 DM	202	{
62fa8a84	203	u32 *p = dst_metrics_write_ptr(dst);
defb3519	204
62fa8a84 DM	205	if (p)
62fa8a84 DM	206	p[metric-1] = val;
1da177e4 LT	207	}
1da177e4 LT	208
0c3adfb8 GBY	209	static inline u32
	210	dst_feature(const struct dst_entry *dst, u32 feature)
	211	{
bb5b7c11	212	return dst_metric(dst, RTAX_FEATURES) & feature;
0c3adfb8 GBY	213	}
0c3adfb8 GBY	214
1da177e4 LT	215	static inline u32 dst_mtu(const struct dst_entry *dst)
1da177e4 LT	216	{
618f9bc7	217	return dst->ops->mtu(dst);
1da177e4 LT	218	}
1da177e4 LT	219
c1e20f7c SH	220	/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
	221	static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
	222	{
	223	return msecs_to_jiffies(dst_metric(dst, metric));
	224	}
	225
1da177e4 LT	226	static inline u32
	227	dst_allfrag(const struct dst_entry *dst)
	228	{
0c3adfb8	229	int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
1da177e4 LT	230	return ret;
	231	}
	232
	233	static inline int
d33e4553	234	dst_metric_locked(const struct dst_entry *dst, int metric)
1da177e4 LT	235	{
	236	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	237	}
	238
7f95e188	239	static inline void dst_hold(struct dst_entry *dst)
1da177e4	240	{
5635c10d ED	241	/*
	242	* If your kernel compilation stops here, please check
	243	* __pad_to_align_refcnt declaration in struct dst_entry
	244	*/
	245	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
1da177e4 LT	246	atomic_inc(&dst->__refcnt);
	247	}
	248
03f49f34 PE	249	static inline void dst_use(struct dst_entry *dst, unsigned long time)
	250	{
	251	dst_hold(dst);
	252	dst->__use++;
	253	dst->lastuse = time;
	254	}
	255
7fee226a ED	256	static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
	257	{
	258	dst->__use++;
	259	dst->lastuse = time;
	260	}
	261
7f95e188	262	static inline struct dst_entry dst_clone(struct dst_entry dst)
1da177e4 LT	263	{
	264	if (dst)
	265	atomic_inc(&dst->__refcnt);
	266	return dst;
	267	}
	268
8d330868	269	extern void dst_release(struct dst_entry *dst);
7fee226a ED	270
	271	static inline void refdst_drop(unsigned long refdst)
	272	{
	273	if (!(refdst & SKB_DST_NOREF))
	274	dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
	275	}
	276
	277	/**
	278	* skb_dst_drop - drops skb dst
	279	* @skb: buffer
	280	*
	281	* Drops dst reference count if a reference was taken.
	282	*/
adf30907 ED	283	static inline void skb_dst_drop(struct sk_buff *skb)
adf30907 ED	284	{
7fee226a ED	285	if (skb->_skb_refdst) {
	286	refdst_drop(skb->_skb_refdst);
	287	skb->_skb_refdst = 0UL;
	288	}
	289	}
	290
	291	static inline void skb_dst_copy(struct sk_buff nskb, const struct sk_buff oskb)
	292	{
	293	nskb->_skb_refdst = oskb->_skb_refdst;
	294	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
	295	dst_clone(skb_dst(nskb));
	296	}
	297
	298	/**
	299	* skb_dst_force - makes sure skb dst is refcounted
	300	* @skb: buffer
	301	*
	302	* If dst is not yet refcounted, let's do it
	303	*/
	304	static inline void skb_dst_force(struct sk_buff *skb)
	305	{
	306	if (skb_dst_is_noref(skb)) {
	307	WARN_ON(!rcu_read_lock_held());
	308	skb->_skb_refdst &= ~SKB_DST_NOREF;
	309	dst_clone(skb_dst(skb));
	310	}
adf30907	311	}
1da177e4	312
d19d56dd	313
290b895e ED	314	/**
	315	* __skb_tunnel_rx - prepare skb for rx reinsert
	316	* @skb: buffer
	317	* @dev: tunnel device
	318	*
	319	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	320	* so make some cleanups. (no accounting done)
	321	*/
	322	static inline void __skb_tunnel_rx(struct sk_buff skb, struct net_device dev)
	323	{
	324	skb->dev = dev;
bdeab991 TH	325
	326	/*
	327	* Clear rxhash so that we can recalulate the hash for the
	328	* encapsulated packet, unless we have already determine the hash
	329	* over the L4 4-tuple.
	330	*/
	331	if (!skb->l4_rxhash)
	332	skb->rxhash = 0;
290b895e ED	333	skb_set_queue_mapping(skb, 0);
	334	skb_dst_drop(skb);
	335	nf_reset(skb);
	336	}
	337
d19d56dd ED	338	/**
	339	* skb_tunnel_rx - prepare skb for rx reinsert
	340	* @skb: buffer
	341	* @dev: tunnel device
	342	*
	343	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	344	* so make some cleanups, and perform accounting.
290b895e	345	* Note: this accounting is not SMP safe.
d19d56dd ED	346	*/
	347	static inline void skb_tunnel_rx(struct sk_buff skb, struct net_device dev)
	348	{
d19d56dd ED	349	/* TODO : stats should be SMP safe */
	350	dev->stats.rx_packets++;
	351	dev->stats.rx_bytes += skb->len;
290b895e	352	__skb_tunnel_rx(skb, dev);
d19d56dd ED	353	}
d19d56dd ED	354
1da177e4 LT	355	/* Children define the path of the packet through the
	356	* Linux networking. Thus, destinations are stackable.
	357	*/
	358
8764ab2c	359	static inline struct dst_entry skb_dst_pop(struct sk_buff skb)
1da177e4	360	{
e433430a	361	struct dst_entry *child = dst_clone(skb_dst(skb)->child);
1da177e4	362
8764ab2c	363	skb_dst_drop(skb);
1da177e4 LT	364	return child;
	365	}
	366
352e512c	367	extern int dst_discard(struct sk_buff *skb);
7f95e188	368	extern void dst_alloc(struct dst_ops ops, struct net_device *dev,
5110effe DM	369	int initial_ref, int initial_obsolete,
5110effe DM	370	unsigned short flags);
7f95e188 EZ	371	extern void __dst_free(struct dst_entry *dst);
7f95e188 EZ	372	extern struct dst_entry dst_destroy(struct dst_entry dst);
1da177e4	373
7f95e188	374	static inline void dst_free(struct dst_entry *dst)
1da177e4	375	{
f5b0a874	376	if (dst->obsolete > 0)
1da177e4 LT	377	return;
	378	if (!atomic_read(&dst->__refcnt)) {
	379	dst = dst_destroy(dst);
	380	if (!dst)
	381	return;
	382	}
	383	__dst_free(dst);
	384	}
	385
	386	static inline void dst_rcu_free(struct rcu_head *head)
	387	{
	388	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
	389	dst_free(dst);
	390	}
	391
	392	static inline void dst_confirm(struct dst_entry *dst)
	393	{
5110effe DM	394	dst->pending_confirm = 1;
5110effe DM	395	}
f2c31e32	396
5110effe DM	397	static inline int dst_neigh_output(struct dst_entry dst, struct neighbour n,
	398	struct sk_buff *skb)
	399	{
425f09ab ED	400	const struct hh_cache *hh;
	401
	402	if (dst->pending_confirm) {
	403	unsigned long now = jiffies;
5110effe	404
5110effe	405	dst->pending_confirm = 0;
425f09ab ED	406	/* avoid dirtying neighbour */
	407	if (n->confirmed != now)
	408	n->confirmed = now;
69cce1d1	409	}
5110effe DM	410
	411	hh = &n->hh;
	412	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
	413	return neigh_hh_output(hh, skb);
	414	else
	415	return n->output(n, skb);
1da177e4 LT	416	}
1da177e4 LT	417
d3aaeb38 DM	418	static inline struct neighbour dst_neigh_lookup(const struct dst_entry dst, const void *daddr)
d3aaeb38 DM	419	{
f894cbf8 DM	420	return dst->ops->neigh_lookup(dst, NULL, daddr);
	421	}
	422
	423	static inline struct neighbour dst_neigh_lookup_skb(const struct dst_entry dst,
	424	struct sk_buff *skb)
	425	{
	426	return dst->ops->neigh_lookup(dst, skb, NULL);
d3aaeb38 DM	427	}
d3aaeb38 DM	428
1da177e4 LT	429	static inline void dst_link_failure(struct sk_buff *skb)
1da177e4 LT	430	{
adf30907	431	struct dst_entry *dst = skb_dst(skb);
1da177e4 LT	432	if (dst && dst->ops && dst->ops->link_failure)
	433	dst->ops->link_failure(skb);
	434	}
	435
	436	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
	437	{
	438	unsigned long expires = jiffies + timeout;
	439
	440	if (expires == 0)
	441	expires = 1;
	442
	443	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
	444	dst->expires = expires;
	445	}
	446
	447	/* Output packet to network from transport. */
	448	static inline int dst_output(struct sk_buff *skb)
	449	{
adf30907	450	return skb_dst(skb)->output(skb);
1da177e4 LT	451	}
	452
	453	/* Input packet from network to transport. */
	454	static inline int dst_input(struct sk_buff *skb)
	455	{
adf30907	456	return skb_dst(skb)->input(skb);
1da177e4 LT	457	}
	458
	459	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	460	{
	461	if (dst->obsolete)
	462	dst = dst->ops->check(dst, cookie);
	463	return dst;
	464	}
	465
	466	extern void dst_init(void);
	467
815f4e57 HX	468	/* Flags for xfrm_lookup flags argument. */
815f4e57 HX	469	enum {
80c0bc9e	470	XFRM_LOOKUP_ICMP = 1 << 0,
815f4e57 HX	471	};
815f4e57 HX	472
1da177e4 LT	473	struct flowi;
1da177e4 LT	474	#ifndef CONFIG_XFRM
452edd59 DM	475	static inline struct dst_entry xfrm_lookup(struct net net,
	476	struct dst_entry *dst_orig,
	477	const struct flowi fl, struct sock sk,
	478	int flags)
1da177e4	479	{
452edd59	480	return dst_orig;
1da177e4 LT	481	}
1da177e4 LT	482	#else
452edd59 DM	483	extern struct dst_entry xfrm_lookup(struct net net, struct dst_entry *dst_orig,
	484	const struct flowi fl, struct sock sk,
	485	int flags);
1da177e4	486	#endif
1da177e4 LT	487
1da177e4 LT	488	#endif /* _NET_DST_H */