/*
* 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 dst_entry *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 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;
unsigned short 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;
kmem_cache_t *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 */
