FreeBSD/Linux Kernel Cross Reference
sys/net/hostcache.h

     /*
      * Copyright 1997 Massachusetts Institute of Technology
      *
      * Permission to use, copy, modify, and distribute this software and
      * its documentation for any purpose and without fee is hereby
      * granted, provided that both the above copyright notice and this
      * permission notice appear in all copies, that both the above
      * copyright notice and this permission notice appear in all
      * supporting documentation, and that the name of M.I.T. not be used
     * in advertising or publicity pertaining to distribution of the
     * software without specific, written prior permission.  M.I.T. makes
     * no representations about the suitability of this software for any
     * purpose.  It is provided "as is" without express or implied
     * warranty.
     * 
     * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
     * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
     * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
     * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
     * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    #ifndef _NET_HOSTCACHE_H
    #define _NET_HOSTCACHE_H        1
    
    /*
     * This file defines the interface between network protocols and
     * the cache of host-specific information maintained by the kernel.
     * The generic interface takes care of inserting and deleting entries,
     * maintaining mutual exclusion, and enforcing policy constraint on the
     * size of the cache and the maximum age of its entries.
     * It replaces an earlier scheme which overloaded the routing table
     * for this purpose, and should be significantly more efficient
     * at performing most operations.  (It does keep a route to each
     * entry in the cache.)  Most protocols will want to define a
     * structure which begins with `struct hcentry' so that they
     * can keep additional, protocol-specific information in it.
     */
    
    #include <sys/queue.h>
    
    struct hcentry {
            LIST_ENTRY(hcentry) hc_link;
            struct  timeval hc_idlesince;   /* time last ref dropped */
            struct  sockaddr *hc_host;      /* address of this entry's host */
            struct  rtentry *hc_rt;         /* route to get there */
            /* struct nexthop *hc_nh; */
            int     hc_refcnt;              /* reference count */
            struct  hctable *hc_hct;        /* back ref to table */
    };
    
    struct hccallback {
            u_long  (*hccb_hash)(struct sockaddr *, u_long);
            int     (*hccb_delete)(struct hcentry *);
            u_long  (*hccb_bump)(u_long);
    };
    
    LIST_HEAD(hchead, hcentry);
    
    struct hctable {
            u_long  hct_nentries;
            u_long  hct_active;
            u_long  hct_idle;
            struct  hchead *hct_heads;
            struct  hccallback *hct_cb;
            int     hct_primes;
    };
    
    #ifdef KERNEL
    
    #ifdef MALLOC_DECLARE
    MALLOC_DECLARE(M_HOSTCACHE);
    #endif
    /*
     * The table-modification functions must be called from user mode, as
     * they may block waiting for memory and/or locks.
     */
    int     hc_init(int af, struct hccallback *hccb, int init_nelem, int primes);
    struct  hcentry *hc_get(struct sockaddr *sa);
    void    hc_ref(struct hcentry *hc);
    void    hc_rele(struct hcentry *hc);
    int     hc_insert(struct hcentry *hc);
    int     hc_delete(struct hcentry *hc);
    #endif /* KERNEL */
    
    #endif /* _NET_HOSTCACHE_H */

Cache object: 8025908ecf9bbbdcb0f221cab6c974df