dst_ops.h

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#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 sock;

struct dst_ops {
    unsigned short      family;
    __be16          protocol;
    unsigned int        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        (*mtu)(const struct dst_entry *);
    u32 *           (*cow_metrics)(struct dst_entry *, unsigned long);
    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, struct sock *sk,
                           struct sk_buff *skb, u32 mtu);
    void            (*redirect)(struct dst_entry *dst, struct sock *sk,
                        struct sk_buff *skb);
    int         (*local_out)(struct sk_buff *skb);
    struct neighbour *  (*neigh_lookup)(const struct dst_entry *dst,
                        struct sk_buff *skb,
                        const void *daddr);

    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