[mirror_ubuntu-zesty-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 <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 */

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

	struct dst_entry	*path;

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

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

	struct  dst_ops	        *ops;

	u32			metrics[RTAX_MAX];

#ifdef CONFIG_NET_CLS_ROUTE
	__u32			tclassid;
#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    *rt_next;
		struct rt6_info   *rt6_next;
		struct dn_route  *dn_next;
	};
};


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

	int			(*gc)(struct dst_ops *ops);
	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			(*local_out)(struct sk_buff *skb);
	int			entry_size;

	atomic_t		entries;
	struct kmem_cache 		*kmem_cachep;
	struct net              *dst_net;
};

#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;
}

extern void dst_release(struct dst_entry *dst);

/* 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);

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

struct flowi;
#ifndef CONFIG_XFRM
static inline int xfrm_lookup(struct 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
69a73829	55	unsigned int rate_tokens;
f1dd9c37	56	unsigned long rate_last; /* rate limiting for ICMP */
69a73829	57
f1dd9c37	58	struct dst_entry *path;
1da177e4	59
1da177e4 LT	60	struct neighbour *neighbour;
	61	struct hh_cache *hh;
	62	struct xfrm_state *xfrm;
	63
	64	int (input)(struct sk_buff);
	65	int (output)(struct sk_buff);
	66
1da177e4	67	struct dst_ops *ops;
f1dd9c37 ZY	68
	69	u32 metrics[RTAX_MAX];
	70
	71	#ifdef CONFIG_NET_CLS_ROUTE
	72	__u32 tclassid;
	73	#endif
	74
	75	/*
	76	* __refcnt wants to be on a different cache line from
	77	* input/output/ops or performance tanks badly
	78	*/
1e19e02c ED	79	atomic_t __refcnt; /* client references */
1e19e02c ED	80	int __use;
f1dd9c37	81	unsigned long lastuse;
1e19e02c ED	82	union {
	83	struct dst_entry *next;
	84	struct rtable *rt_next;
	85	struct rt6_info *rt6_next;
	86	struct dn_route *dn_next;
	87	};
1da177e4 LT	88	};
	89
	90
	91	struct dst_ops
	92	{
	93	unsigned short family;
d77072ec	94	__be16 protocol;
1da177e4 LT	95	unsigned gc_thresh;
1da177e4 LT	96
569d3645	97	int (gc)(struct dst_ops ops);
1da177e4 LT	98	struct dst_entry * (check)(struct dst_entry , __u32 cookie);
	99	void (destroy)(struct dst_entry );
	100	void (ifdown)(struct dst_entry ,
	101	struct net_device *dev, int how);
	102	struct dst_entry * (negative_advice)(struct dst_entry );
	103	void (link_failure)(struct sk_buff );
	104	void (update_pmtu)(struct dst_entry dst, u32 mtu);
862b82c6	105	int (local_out)(struct sk_buff skb);
1da177e4 LT	106	int entry_size;
	107
	108	atomic_t entries;
e18b890b	109	struct kmem_cache *kmem_cachep;
d4fa26ff	110	struct net *dst_net;
1da177e4 LT	111	};
	112
	113	#ifdef __KERNEL__
	114
	115	static inline u32
	116	dst_metric(const struct dst_entry *dst, int metric)
	117	{
	118	return dst->metrics[metric-1];
	119	}
	120
	121	static inline u32 dst_mtu(const struct dst_entry *dst)
	122	{
	123	u32 mtu = dst_metric(dst, RTAX_MTU);
	124	/*
	125	* Alexey put it here, so ask him about it :)
	126	*/
	127	barrier();
	128	return mtu;
	129	}
	130
	131	static inline u32
	132	dst_allfrag(const struct dst_entry *dst)
	133	{
	134	int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
	135	/* Yes, _exactly_. This is paranoia. */
	136	barrier();
	137	return ret;
	138	}
	139
	140	static inline int
	141	dst_metric_locked(struct dst_entry *dst, int metric)
	142	{
	143	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	144	}
	145
	146	static inline void dst_hold(struct dst_entry * dst)
	147	{
	148	atomic_inc(&dst->__refcnt);
	149	}
	150
03f49f34 PE	151	static inline void dst_use(struct dst_entry *dst, unsigned long time)
	152	{
	153	dst_hold(dst);
	154	dst->__use++;
	155	dst->lastuse = time;
	156	}
	157
1da177e4 LT	158	static inline
	159	struct dst_entry * dst_clone(struct dst_entry * dst)
	160	{
	161	if (dst)
	162	atomic_inc(&dst->__refcnt);
	163	return dst;
	164	}
	165
8d330868	166	extern void dst_release(struct dst_entry *dst);
1da177e4 LT	167
	168	/* Children define the path of the packet through the
	169	* Linux networking. Thus, destinations are stackable.
	170	*/
	171
	172	static inline struct dst_entry dst_pop(struct dst_entry dst)
	173	{
	174	struct dst_entry *child = dst_clone(dst->child);
	175
	176	dst_release(dst);
	177	return child;
	178	}
	179
352e512c	180	extern int dst_discard(struct sk_buff *skb);
1da177e4 LT	181	extern void * dst_alloc(struct dst_ops * ops);
	182	extern void __dst_free(struct dst_entry * dst);
	183	extern struct dst_entry dst_destroy(struct dst_entry dst);
	184
	185	static inline void dst_free(struct dst_entry * dst)
	186	{
	187	if (dst->obsolete > 1)
	188	return;
	189	if (!atomic_read(&dst->__refcnt)) {
	190	dst = dst_destroy(dst);
	191	if (!dst)
	192	return;
	193	}
	194	__dst_free(dst);
	195	}
	196
	197	static inline void dst_rcu_free(struct rcu_head *head)
	198	{
	199	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
	200	dst_free(dst);
	201	}
	202
	203	static inline void dst_confirm(struct dst_entry *dst)
	204	{
	205	if (dst)
	206	neigh_confirm(dst->neighbour);
	207	}
	208
	209	static inline void dst_negative_advice(struct dst_entry **dst_p)
	210	{
	211	struct dst_entry * dst = *dst_p;
	212	if (dst && dst->ops->negative_advice)
	213	*dst_p = dst->ops->negative_advice(dst);
	214	}
	215
	216	static inline void dst_link_failure(struct sk_buff *skb)
	217	{
	218	struct dst_entry * dst = skb->dst;
	219	if (dst && dst->ops && dst->ops->link_failure)
	220	dst->ops->link_failure(skb);
	221	}
	222
	223	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
	224	{
	225	unsigned long expires = jiffies + timeout;
	226
	227	if (expires == 0)
	228	expires = 1;
	229
	230	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
	231	dst->expires = expires;
	232	}
	233
	234	/* Output packet to network from transport. */
	235	static inline int dst_output(struct sk_buff *skb)
	236	{
16a6677f	237	return skb->dst->output(skb);
1da177e4 LT	238	}
	239
	240	/* Input packet from network to transport. */
	241	static inline int dst_input(struct sk_buff *skb)
	242	{
	243	int err;
	244
	245	for (;;) {
	246	err = skb->dst->input(skb);
	247
	248	if (likely(err == 0))
	249	return err;
	250	/* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
	251	if (unlikely(err != NET_XMIT_BYPASS))
	252	return err;
	253	}
	254	}
	255
	256	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	257	{
	258	if (dst->obsolete)
	259	dst = dst->ops->check(dst, cookie);
	260	return dst;
	261	}
	262
	263	extern void dst_init(void);
	264
815f4e57 HX	265	/* Flags for xfrm_lookup flags argument. */
	266	enum {
	267	XFRM_LOOKUP_WAIT = 1 << 0,
8b7817f3	268	XFRM_LOOKUP_ICMP = 1 << 1,
815f4e57 HX	269	};
815f4e57 HX	270
1da177e4 LT	271	struct flowi;
	272	#ifndef CONFIG_XFRM
	273	static inline int xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
	274	struct sock *sk, int flags)
	275	{
	276	return 0;
	277	}
14e50e57 DM	278	static inline int __xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
	279	struct sock *sk, int flags)
	280	{
	281	return 0;
	282	}
1da177e4 LT	283	#else
	284	extern int xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
	285	struct sock *sk, int flags);
14e50e57 DM	286	extern int __xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
14e50e57 DM	287	struct sock *sk, int flags);
1da177e4 LT	288	#endif
	289	#endif
	290
	291	#endif /* _NET_DST_H */