[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 <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;
	short			error;
	short			obsolete;
	int			flags;
#define DST_HOST		1
#define DST_NOXFRM		2
#define DST_NOPOLICY		4
#define DST_NOHASH		8
	unsigned long		expires;

	unsigned short		header_len;	/* more space at head required */
	unsigned short		trailer_len;	/* space to reserve at tail */

	u32			metrics[RTAX_MAX];
	struct dst_entry	*path;

	unsigned long		rate_last;	/* rate limiting for ICMP */
	unsigned long		rate_tokens;

	struct neighbour	*neighbour;
	struct hh_cache		*hh;
	struct xfrm_state	*xfrm;

	int			(*input)(struct sk_buff*);
	int			(*output)(struct sk_buff*);

#ifdef CONFIG_NET_CLS_ROUTE
	__u32			tclassid;
#endif

	struct  dst_ops	        *ops;
		
	unsigned long		lastuse;
	atomic_t		__refcnt;	/* client references	*/
	int			__use;
	union {
		struct dst_entry *next;
		struct rtable    *rt_next;
		struct rt6_info   *rt6_next;
		struct dn_route  *dn_next;
	};
	char			info[0];
};


struct dst_ops
{
	unsigned short		family;
	__be16			protocol;
	unsigned		gc_thresh;

	int			(*gc)(void);
	struct dst_entry *	(*check)(struct dst_entry *, __u32 cookie);
	void			(*destroy)(struct dst_entry *);
	void			(*ifdown)(struct dst_entry *,
					  struct net_device *dev, int how);
	struct dst_entry *	(*negative_advice)(struct dst_entry *);
	void			(*link_failure)(struct sk_buff *);
	void			(*update_pmtu)(struct dst_entry *dst, u32 mtu);
	int			entry_size;

	atomic_t		entries;
	struct kmem_cache 		*kmem_cachep;
};

#ifdef __KERNEL__

static inline u32
dst_metric(const struct dst_entry *dst, int metric)
{
	return dst->metrics[metric-1];
}

static inline u32 dst_mtu(const struct dst_entry *dst)
{
	u32 mtu = dst_metric(dst, RTAX_MTU);
	/*
	 * Alexey put it here, so ask him about it :)
	 */
	barrier();
	return mtu;
}

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

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

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

static inline
void dst_release(struct dst_entry * dst)
{
	if (dst) {
		WARN_ON(atomic_read(&dst->__refcnt) < 1);
		smp_mb__before_atomic_dec();
		atomic_dec(&dst->__refcnt);
	}
}

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

static inline struct dst_entry *dst_pop(struct dst_entry *dst)
{
	struct dst_entry *child = dst_clone(dst->child);

	dst_release(dst);
	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_negative_advice(struct dst_entry **dst_p)
{
	struct dst_entry * dst = *dst_p;
	if (dst && dst->ops->negative_advice)
		*dst_p = dst->ops->negative_advice(dst);
}

static inline void dst_link_failure(struct sk_buff *skb)
{
	struct dst_entry * dst = skb->dst;
	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->output(skb);
}

/* Input packet from network to transport.  */
static inline int dst_input(struct sk_buff *skb)
{
	int err;

	for (;;) {
		err = skb->dst->input(skb);

		if (likely(err == 0))
			return err;
		/* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
		if (unlikely(err != NET_XMIT_BYPASS))
			return err;
	}
}

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);

struct flowi;
#ifndef CONFIG_XFRM
static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
		       struct sock *sk, int flags)
{
	return 0;
} 
static inline int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
				struct sock *sk, int flags)
{
	return 0;
}
#else
extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
		       struct sock *sk, int flags);
extern int __xfrm_lookup(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
14c85021	11	#include <linux/netdevice.h>
1da177e4 LT	12	#include <linux/rtnetlink.h>
	13	#include <linux/rcupdate.h>
	14	#include <linux/jiffies.h>
	15	#include <net/neighbour.h>
	16	#include <asm/processor.h>
	17
	18	/*
	19	* 0 - no debugging messages
	20	* 1 - rare events and bugs (default)
	21	* 2 - trace mode.
	22	*/
	23	#define RT_CACHE_DEBUG 0
	24
	25	#define DST_GC_MIN (HZ/10)
	26	#define DST_GC_INC (HZ/2)
	27	#define DST_GC_MAX (120*HZ)
	28
	29	/* Each dst_entry has reference count and sits in some parent list(s).
	30	* When it is removed from parent list, it is "freed" (dst_free).
	31	* After this it enters dead state (dst->obsolete > 0) and if its refcnt
	32	* is zero, it can be destroyed immediately, otherwise it is added
	33	* to gc list and garbage collector periodically checks the refcnt.
	34	*/
	35
	36	struct sk_buff;
	37
	38	struct dst_entry
	39	{
1e19e02c	40	struct rcu_head rcu_head;
1da177e4 LT	41	struct dst_entry *child;
1da177e4 LT	42	struct net_device *dev;
c4d54110 HX	43	short error;
c4d54110 HX	44	short obsolete;
1da177e4 LT	45	int flags;
	46	#define DST_HOST 1
	47	#define DST_NOXFRM 2
	48	#define DST_NOPOLICY 4
	49	#define DST_NOHASH 8
1da177e4 LT	50	unsigned long expires;
	51
	52	unsigned short header_len; /* more space at head required */
	53	unsigned short trailer_len; /* space to reserve at tail */
	54
	55	u32 metrics[RTAX_MAX];
	56	struct dst_entry *path;
	57
	58	unsigned long rate_last; /* rate limiting for ICMP */
	59	unsigned long rate_tokens;
	60
1da177e4 LT	61	struct neighbour *neighbour;
	62	struct hh_cache *hh;
	63	struct xfrm_state *xfrm;
	64
	65	int (input)(struct sk_buff);
	66	int (output)(struct sk_buff);
	67
	68	#ifdef CONFIG_NET_CLS_ROUTE
	69	__u32 tclassid;
	70	#endif
	71
	72	struct dst_ops *ops;
1da177e4	73
1e19e02c ED	74	unsigned long lastuse;
	75	atomic_t __refcnt; /* client references */
	76	int __use;
	77	union {
	78	struct dst_entry *next;
	79	struct rtable *rt_next;
	80	struct rt6_info *rt6_next;
	81	struct dn_route *dn_next;
	82	};
1da177e4 LT	83	char info[0];
	84	};
	85
	86
	87	struct dst_ops
	88	{
	89	unsigned short family;
d77072ec	90	__be16 protocol;
1da177e4 LT	91	unsigned gc_thresh;
	92
	93	int (*gc)(void);
	94	struct dst_entry * (check)(struct dst_entry , __u32 cookie);
	95	void (destroy)(struct dst_entry );
	96	void (ifdown)(struct dst_entry ,
	97	struct net_device *dev, int how);
	98	struct dst_entry * (negative_advice)(struct dst_entry );
	99	void (link_failure)(struct sk_buff );
	100	void (update_pmtu)(struct dst_entry dst, u32 mtu);
1da177e4 LT	101	int entry_size;
	102
	103	atomic_t entries;
e18b890b	104	struct kmem_cache *kmem_cachep;
1da177e4 LT	105	};
	106
	107	#ifdef __KERNEL__
	108
	109	static inline u32
	110	dst_metric(const struct dst_entry *dst, int metric)
	111	{
	112	return dst->metrics[metric-1];
	113	}
	114
	115	static inline u32 dst_mtu(const struct dst_entry *dst)
	116	{
	117	u32 mtu = dst_metric(dst, RTAX_MTU);
	118	/*
	119	* Alexey put it here, so ask him about it :)
	120	*/
	121	barrier();
	122	return mtu;
	123	}
	124
	125	static inline u32
	126	dst_allfrag(const struct dst_entry *dst)
	127	{
	128	int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
	129	/* Yes, _exactly_. This is paranoia. */
	130	barrier();
	131	return ret;
	132	}
	133
	134	static inline int
	135	dst_metric_locked(struct dst_entry *dst, int metric)
	136	{
	137	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	138	}
	139
	140	static inline void dst_hold(struct dst_entry * dst)
	141	{
	142	atomic_inc(&dst->__refcnt);
	143	}
	144
03f49f34 PE	145	static inline void dst_use(struct dst_entry *dst, unsigned long time)
	146	{
	147	dst_hold(dst);
	148	dst->__use++;
	149	dst->lastuse = time;
	150	}
	151
1da177e4 LT	152	static inline
	153	struct dst_entry * dst_clone(struct dst_entry * dst)
	154	{
	155	if (dst)
	156	atomic_inc(&dst->__refcnt);
	157	return dst;
	158	}
	159
	160	static inline
	161	void dst_release(struct dst_entry * dst)
	162	{
	163	if (dst) {
	164	WARN_ON(atomic_read(&dst->__refcnt) < 1);
	165	smp_mb__before_atomic_dec();
	166	atomic_dec(&dst->__refcnt);
	167	}
	168	}
	169
	170	/* Children define the path of the packet through the
	171	* Linux networking. Thus, destinations are stackable.
	172	*/
	173
	174	static inline struct dst_entry dst_pop(struct dst_entry dst)
	175	{
	176	struct dst_entry *child = dst_clone(dst->child);
	177
	178	dst_release(dst);
	179	return child;
	180	}
	181
352e512c	182	extern int dst_discard(struct sk_buff *skb);
1da177e4 LT	183	extern void * dst_alloc(struct dst_ops * ops);
	184	extern void __dst_free(struct dst_entry * dst);
	185	extern struct dst_entry dst_destroy(struct dst_entry dst);
	186
	187	static inline void dst_free(struct dst_entry * dst)
	188	{
	189	if (dst->obsolete > 1)
	190	return;
	191	if (!atomic_read(&dst->__refcnt)) {
	192	dst = dst_destroy(dst);
	193	if (!dst)
	194	return;
	195	}
	196	__dst_free(dst);
	197	}
	198
	199	static inline void dst_rcu_free(struct rcu_head *head)
	200	{
	201	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
	202	dst_free(dst);
	203	}
	204
	205	static inline void dst_confirm(struct dst_entry *dst)
	206	{
	207	if (dst)
	208	neigh_confirm(dst->neighbour);
	209	}
	210
	211	static inline void dst_negative_advice(struct dst_entry **dst_p)
	212	{
	213	struct dst_entry * dst = *dst_p;
	214	if (dst && dst->ops->negative_advice)
	215	*dst_p = dst->ops->negative_advice(dst);
	216	}
	217
	218	static inline void dst_link_failure(struct sk_buff *skb)
	219	{
	220	struct dst_entry * dst = skb->dst;
	221	if (dst && dst->ops && dst->ops->link_failure)
	222	dst->ops->link_failure(skb);
	223	}
	224
	225	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
	226	{
	227	unsigned long expires = jiffies + timeout;
	228
	229	if (expires == 0)
	230	expires = 1;
	231
	232	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
	233	dst->expires = expires;
	234	}
	235
	236	/* Output packet to network from transport. */
	237	static inline int dst_output(struct sk_buff *skb)
	238	{
16a6677f	239	return skb->dst->output(skb);
1da177e4 LT	240	}
	241
	242	/* Input packet from network to transport. */
	243	static inline int dst_input(struct sk_buff *skb)
	244	{
	245	int err;
	246
	247	for (;;) {
	248	err = skb->dst->input(skb);
	249
	250	if (likely(err == 0))
	251	return err;
	252	/* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
	253	if (unlikely(err != NET_XMIT_BYPASS))
	254	return err;
	255	}
	256	}
	257
	258	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	259	{
	260	if (dst->obsolete)
	261	dst = dst->ops->check(dst, cookie);
	262	return dst;
	263	}
	264
	265	extern void dst_init(void);
	266
	267	struct flowi;
	268	#ifndef CONFIG_XFRM
	269	static inline int xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
	270	struct sock *sk, int flags)
	271	{
	272	return 0;
	273	}
14e50e57 DM	274	static inline int __xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
	275	struct sock *sk, int flags)
	276	{
	277	return 0;
	278	}
1da177e4 LT	279	#else
	280	extern int xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
	281	struct sock *sk, int flags);
14e50e57 DM	282	extern int __xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
14e50e57 DM	283	struct sock *sk, int flags);
1da177e4 LT	284	#endif
	285	#endif
	286
	287	#endif /* _NET_DST_H */