kernel-ark/include/net/dst_ops.h
David S. Miller d33e455337 net: Abstract default MTU metric calculation behind an accessor.
Like RTAX_ADVMSS, make the default calculation go through a dst_ops
method rather than caching the computation in the routing cache
entries.

Now dst metrics are pretty much left as-is when new entries are
created, thus optimizing metric sharing becomes a real possibility.

Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-14 13:01:14 -08:00

67 lines
1.6 KiB
C

#ifndef _NET_DST_OPS_H
#define _NET_DST_OPS_H
#include <linux/types.h>
#include <linux/percpu_counter.h>
#include <linux/cache.h>
struct dst_entry;
struct kmem_cachep;
struct net_device;
struct sk_buff;
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);
unsigned int (*default_advmss)(const struct dst_entry *);
unsigned int (*default_mtu)(const struct dst_entry *);
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);
struct kmem_cache *kmem_cachep;
struct percpu_counter pcpuc_entries ____cacheline_aligned_in_smp;
};
static inline int dst_entries_get_fast(struct dst_ops *dst)
{
return percpu_counter_read_positive(&dst->pcpuc_entries);
}
static inline int dst_entries_get_slow(struct dst_ops *dst)
{
int res;
local_bh_disable();
res = percpu_counter_sum_positive(&dst->pcpuc_entries);
local_bh_enable();
return res;
}
static inline void dst_entries_add(struct dst_ops *dst, int val)
{
local_bh_disable();
percpu_counter_add(&dst->pcpuc_entries, val);
local_bh_enable();
}
static inline int dst_entries_init(struct dst_ops *dst)
{
return percpu_counter_init(&dst->pcpuc_entries, 0);
}
static inline void dst_entries_destroy(struct dst_ops *dst)
{
percpu_counter_destroy(&dst->pcpuc_entries);
}
#endif