[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
{
	union {
		struct dst_entry *next;
		struct rtable    *rt_next;
		struct rt6_info   *rt6_next;
		struct dn_route  *dn_next;
	};
	atomic_t		__refcnt;	/* client references	*/
	int			__use;
	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
#define DST_BALANCED            0x10
	unsigned long		lastuse;
	unsigned long		expires;

	unsigned short		header_len;	/* more space at head required */
	unsigned short		nfheader_len;	/* more non-fragment 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;
	struct rcu_head		rcu_head;
		
	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
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 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;
} 
#else
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	{
75ce7cea ED	40	union {
	41	struct dst_entry *next;
	42	struct rtable *rt_next;
	43	struct rt6_info *rt6_next;
	44	struct dn_route *dn_next;
	45	};
1da177e4 LT	46	atomic_t __refcnt; /* client references */
	47	int __use;
	48	struct dst_entry *child;
	49	struct net_device *dev;
c4d54110 HX	50	short error;
c4d54110 HX	51	short obsolete;
1da177e4 LT	52	int flags;
	53	#define DST_HOST 1
	54	#define DST_NOXFRM 2
	55	#define DST_NOPOLICY 4
	56	#define DST_NOHASH 8
	57	#define DST_BALANCED 0x10
	58	unsigned long lastuse;
	59	unsigned long expires;
	60
	61	unsigned short header_len; /* more space at head required */
1b5c2299	62	unsigned short nfheader_len; /* more non-fragment space at head required */
1da177e4 LT	63	unsigned short trailer_len; /* space to reserve at tail */
	64
	65	u32 metrics[RTAX_MAX];
	66	struct dst_entry *path;
	67
	68	unsigned long rate_last; /* rate limiting for ICMP */
	69	unsigned long rate_tokens;
	70
1da177e4 LT	71	struct neighbour *neighbour;
	72	struct hh_cache *hh;
	73	struct xfrm_state *xfrm;
	74
	75	int (input)(struct sk_buff);
	76	int (output)(struct sk_buff);
	77
	78	#ifdef CONFIG_NET_CLS_ROUTE
	79	__u32 tclassid;
	80	#endif
	81
	82	struct dst_ops *ops;
	83	struct rcu_head rcu_head;
	84
	85	char info[0];
	86	};
	87
	88
	89	struct dst_ops
	90	{
	91	unsigned short family;
d77072ec	92	__be16 protocol;
1da177e4 LT	93	unsigned gc_thresh;
	94
	95	int (*gc)(void);
	96	struct dst_entry * (check)(struct dst_entry , __u32 cookie);
	97	void (destroy)(struct dst_entry );
	98	void (ifdown)(struct dst_entry ,
	99	struct net_device *dev, int how);
	100	struct dst_entry * (negative_advice)(struct dst_entry );
	101	void (link_failure)(struct sk_buff );
	102	void (update_pmtu)(struct dst_entry dst, u32 mtu);
1da177e4 LT	103	int entry_size;
	104
	105	atomic_t entries;
e18b890b	106	struct kmem_cache *kmem_cachep;
1da177e4 LT	107	};
	108
	109	#ifdef __KERNEL__
	110
	111	static inline u32
	112	dst_metric(const struct dst_entry *dst, int metric)
	113	{
	114	return dst->metrics[metric-1];
	115	}
	116
	117	static inline u32 dst_mtu(const struct dst_entry *dst)
	118	{
	119	u32 mtu = dst_metric(dst, RTAX_MTU);
	120	/*
	121	* Alexey put it here, so ask him about it :)
	122	*/
	123	barrier();
	124	return mtu;
	125	}
	126
	127	static inline u32
	128	dst_allfrag(const struct dst_entry *dst)
	129	{
	130	int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
	131	/* Yes, _exactly_. This is paranoia. */
	132	barrier();
	133	return ret;
	134	}
	135
	136	static inline int
	137	dst_metric_locked(struct dst_entry *dst, int metric)
	138	{
	139	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	140	}
	141
	142	static inline void dst_hold(struct dst_entry * dst)
	143	{
	144	atomic_inc(&dst->__refcnt);
	145	}
	146
	147	static inline
	148	struct dst_entry * dst_clone(struct dst_entry * dst)
	149	{
	150	if (dst)
	151	atomic_inc(&dst->__refcnt);
	152	return dst;
	153	}
	154
	155	static inline
	156	void dst_release(struct dst_entry * dst)
	157	{
	158	if (dst) {
	159	WARN_ON(atomic_read(&dst->__refcnt) < 1);
	160	smp_mb__before_atomic_dec();
	161	atomic_dec(&dst->__refcnt);
	162	}
	163	}
	164
	165	/* Children define the path of the packet through the
	166	* Linux networking. Thus, destinations are stackable.
	167	*/
	168
	169	static inline struct dst_entry dst_pop(struct dst_entry dst)
	170	{
171	struct dst_entry *child = dst_clone(dst->child);
172
173	dst_release(dst);
174	return child;
175	}
176
177	extern void * dst_alloc(struct dst_ops * ops);
178	extern void __dst_free(struct dst_entry * dst);
179	extern struct dst_entry dst_destroy(struct dst_entry dst);
180
181	static inline void dst_free(struct dst_entry * dst)
182	{
183	if (dst->obsolete > 1)
184	return;
185	if (!atomic_read(&dst->__refcnt)) {
186	dst = dst_destroy(dst);
187	if (!dst)
188	return;
189	}
190	__dst_free(dst);
191	}
192
193	static inline void dst_rcu_free(struct rcu_head *head)
194	{
195	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
196	dst_free(dst);
197	}
198
199	static inline void dst_confirm(struct dst_entry *dst)
200	{
201	if (dst)
202	neigh_confirm(dst->neighbour);
203	}
204
205	static inline void dst_negative_advice(struct dst_entry **dst_p)
206	{
207	struct dst_entry * dst = *dst_p;
208	if (dst && dst->ops->negative_advice)
209	*dst_p = dst->ops->negative_advice(dst);
210	}
211
212	static inline void dst_link_failure(struct sk_buff *skb)
213	{
214	struct dst_entry * dst = skb->dst;
215	if (dst && dst->ops && dst->ops->link_failure)
216	dst->ops->link_failure(skb);
217	}
218
219	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
220	{
221	unsigned long expires = jiffies + timeout;
222
223	if (expires == 0)
224	expires = 1;
225
226	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
227	dst->expires = expires;
228	}
229
230	/* Output packet to network from transport. */
231	static inline int dst_output(struct sk_buff *skb)
232	{
16a6677f	233	return skb->dst->output(skb);
1da177e4 LT	234	}
	235
	236	/* Input packet from network to transport. */
	237	static inline int dst_input(struct sk_buff *skb)
	238	{
	239	int err;
	240
	241	for (;;) {
	242	err = skb->dst->input(skb);
	243
	244	if (likely(err == 0))
	245	return err;
	246	/* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
	247	if (unlikely(err != NET_XMIT_BYPASS))
	248	return err;
	249	}
	250	}
	251
	252	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	253	{
	254	if (dst->obsolete)
	255	dst = dst->ops->check(dst, cookie);
	256	return dst;
	257	}
	258
	259	extern void dst_init(void);
	260
	261	struct flowi;
	262	#ifndef CONFIG_XFRM
	263	static inline int xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
	264	struct sock *sk, int flags)
	265	{
	266	return 0;
	267	}
	268	#else
	269	extern int xfrm_lookup(struct dst_entry *dst_p, struct flowi fl,
	270	struct sock *sk, int flags);
	271	#endif
	272	#endif
	273
	274	#endif /* _NET_DST_H */