root/include/net/inetpeer.h

INCLUDED FROM

DEFINITIONS

1. inetpeer_ptr
2. inetpeer_base_ptr
3. inetpeer_ptr_is_peer
4. __inetpeer_ptr_set_peer
5. inetpeer_ptr_set_peer
6. inetpeer_init_ptr
7. inetpeer_transfer_peer
8. inet_initpeers
9. inet_getpeer_v4
10. inet_getpeer_v6
11. inet_peer_refcheck

/*
 *              INETPEER - A storage for permanent information about peers
 *
 *  Authors:    Andrey V. Savochkin <saw@msu.ru>
 */

#ifndef _NET_INETPEER_H
#define _NET_INETPEER_H

#include <linux/types.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/spinlock.h>
#include <linux/rtnetlink.h>
#include <net/ipv6.h>
#include <linux/atomic.h>

struct inetpeer_addr_base {
        union {
                __be32                  a4;
                __be32                  a6[4];
        };
};

struct inetpeer_addr {
        struct inetpeer_addr_base       addr;
        __u16                           family;
};

struct inet_peer {
        /* group together avl_left,avl_right,v4daddr to speedup lookups */
        struct inet_peer __rcu  *avl_left, *avl_right;
        struct inetpeer_addr    daddr;
        __u32                   avl_height;

        u32                     metrics[RTAX_MAX];
        u32                     rate_tokens;    /* rate limiting for ICMP */
        unsigned long           rate_last;
        union {
                struct list_head        gc_list;
                struct rcu_head     gc_rcu;
        };
        /*
         * Once inet_peer is queued for deletion (refcnt == -1), following field
         * is not available: rid
         * We can share memory with rcu_head to help keep inet_peer small.
         */
        union {
                struct {
                        atomic_t                        rid;            /* Frag reception counter */
                };
                struct rcu_head         rcu;
                struct inet_peer        *gc_next;
        };

        /* following fields might be frequently dirtied */
        __u32                   dtime;  /* the time of last use of not referenced entries */
        atomic_t                refcnt;
};

struct inet_peer_base {
        struct inet_peer __rcu  *root;
        seqlock_t               lock;
        int                     total;
};

#define INETPEER_BASE_BIT       0x1UL

static inline struct inet_peer *inetpeer_ptr(unsigned long val)
{
        BUG_ON(val & INETPEER_BASE_BIT);
        return (struct inet_peer *) val;
}

static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
{
        if (!(val & INETPEER_BASE_BIT))
                return NULL;
        val &= ~INETPEER_BASE_BIT;
        return (struct inet_peer_base *) val;
}

static inline bool inetpeer_ptr_is_peer(unsigned long val)
{
        return !(val & INETPEER_BASE_BIT);
}

static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
{
        /* This implicitly clears INETPEER_BASE_BIT */
        *val = (unsigned long) peer;
}

static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
{
        unsigned long val = (unsigned long) peer;
        unsigned long orig = *ptr;

        if (!(orig & INETPEER_BASE_BIT) ||
            cmpxchg(ptr, orig, val) != orig)
                return false;
        return true;
}

static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
{
        *ptr = (unsigned long) base | INETPEER_BASE_BIT;
}

static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
{
        unsigned long val = *from;

        *to = val;
        if (inetpeer_ptr_is_peer(val)) {
                struct inet_peer *peer = inetpeer_ptr(val);
                atomic_inc(&peer->refcnt);
        }
}

void inet_peer_base_init(struct inet_peer_base *);

void inet_initpeers(void) __init;

#define INETPEER_METRICS_NEW    (~(u32) 0)

static inline bool inet_metrics_new(const struct inet_peer *p)
{
        return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
}

/* can be called with or without local BH being disabled */
struct inet_peer *inet_getpeer(struct inet_peer_base *base,
                               const struct inetpeer_addr *daddr,
                               int create);

static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
                                                __be32 v4daddr,
                                                int create)
{
        struct inetpeer_addr daddr;

        daddr.addr.a4 = v4daddr;
        daddr.family = AF_INET;
        return inet_getpeer(base, &daddr, create);
}

static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
                                                const struct in6_addr *v6daddr,
                                                int create)
{
        struct inetpeer_addr daddr;

        *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
        daddr.family = AF_INET6;
        return inet_getpeer(base, &daddr, create);
}

/* can be called from BH context or outside */
void inet_putpeer(struct inet_peer *p);
bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);

void inetpeer_invalidate_tree(struct inet_peer_base *);

/*
 * temporary check to make sure we dont access rid, tcp_ts,
 * tcp_ts_stamp if no refcount is taken on inet_peer
 */
static inline void inet_peer_refcheck(const struct inet_peer *p)
{
        WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
}
#endif /* _NET_INETPEER_H */