sys/net/hostcache.h

   1 /*
   2  * Copyright 1997 Massachusetts Institute of Technology
   3  *
   4  * Permission to use, copy, modify, and distribute this software and
   5  * its documentation for any purpose and without fee is hereby
   6  * granted, provided that both the above copyright notice and this
   7  * permission notice appear in all copies, that both the above
   8  * copyright notice and this permission notice appear in all
   9  * supporting documentation, and that the name of M.I.T. not be used
  10  * in advertising or publicity pertaining to distribution of the
  11  * software without specific, written prior permission.  M.I.T. makes
  12  * no representations about the suitability of this software for any
  13  * purpose.  It is provided "as is" without express or implied
  14  * warranty.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
  17  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
  18  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
  20  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  23  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  26  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/sys/net/hostcache.h,v 1.4 1999/12/29 04:38:32 peter Exp $
  30  * $DragonFly: src/sys/net/Attic/hostcache.h,v 1.4 2006/05/20 02:42:08 dillon Exp $
  31  */
  32
  33 #ifndef _NET_HOSTCACHE_H_
  34 #define _NET_HOSTCACHE_H_
  35
  36 #ifndef _SYS_TYPES_H_
  37 #include <sys/types.h>
  38 #endif
  39 #ifndef _SYS_TIME_H_
  40 #include <sys/time.h>
  41 #endif
  42
  43 /*
  44  * This file defines the interface between network protocols and
  45  * the cache of host-specific information maintained by the kernel.
  46  * The generic interface takes care of inserting and deleting entries,
  47  * maintaining mutual exclusion, and enforcing policy constraint on the
  48  * size of the cache and the maximum age of its entries.
  49  * It replaces an earlier scheme which overloaded the routing table
  50  * for this purpose, and should be significantly more efficient
  51  * at performing most operations.  (It does keep a route to each
  52  * entry in the cache.)  Most protocols will want to define a
  53  * structure which begins with `struct hcentry' so that they
  54  * can keep additional, protocol-specific information in it.
  55  */
  56
  57 #include <sys/queue.h>
  58
  59 struct hcentry {
  60         LIST_ENTRY(hcentry) hc_link;
  61         struct  timeval hc_idlesince;   /* time last ref dropped */
  62         struct  sockaddr *hc_host;      /* address of this entry's host */
  63         struct  rtentry *hc_rt;         /* route to get there */
  64         /* struct nexthop *hc_nh; */
  65         int     hc_refcnt;              /* reference count */
  66         struct  hctable *hc_hct;        /* back ref to table */
  67 };
  68
  69 struct hccallback {
  70         u_long  (*hccb_hash)(struct sockaddr *, u_long);
  71         int     (*hccb_delete)(struct hcentry *);
  72         u_long  (*hccb_bump)(u_long);
  73 };
  74
  75 LIST_HEAD(hchead, hcentry);
  76
  77 struct hctable {
  78         u_long  hct_nentries;
  79         u_long  hct_active;
  80         u_long  hct_idle;
  81         struct  hchead *hct_heads;
  82         struct  hccallback *hct_cb;
  83         int     hct_primes;
  84 };
  85
  86 #ifdef _KERNEL
  87
  88 #ifdef MALLOC_DECLARE
  89 MALLOC_DECLARE(M_HOSTCACHE);
  90 #endif
  91 /*
  92  * The table-modification functions must be called from user mode, as
  93  * they may block waiting for memory and/or locks.
  94  */
  95 int     hc_init(int af, struct hccallback *hccb, int init_nelem, int primes);
  96 struct  hcentry *hc_get(struct sockaddr *sa);
  97 void    hc_ref(struct hcentry *hc);
  98 void    hc_rele(struct hcentry *hc);
  99 int     hc_insert(struct hcentry *hc);
 100 int     hc_delete(struct hcentry *hc);
 101 #endif
 102
 103 #endif /* _NET_HOSTCACHE_H_ */