include/net/dst.h - maze/linux - Git at Google

 /*
  * 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;
 }

 /* 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 void set_dst_metric_rtt(struct dst_entry *dst, int metric,
 				      unsigned long rtt)
 {
 	dst->metrics[metric-1] = jiffies_to_msecs(rtt);
 }

 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 */
	/*
	* 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;
	}

	/* 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 void set_dst_metric_rtt(struct dst_entry *dst, int metric,
	unsigned long rtt)
	{
	dst->metrics[metric-1] = jiffies_to_msecs(rtt);
	}

	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 */