bsd/net/hostcache.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright 1997 Massachusetts Institute of Technology
  24  *
  25  * Permission to use, copy, modify, and distribute this software and
  26  * its documentation for any purpose and without fee is hereby
  27  * granted, provided that both the above copyright notice and this
  28  * permission notice appear in all copies, that both the above
  29  * copyright notice and this permission notice appear in all
  30  * supporting documentation, and that the name of M.I.T. not be used
  31  * in advertising or publicity pertaining to distribution of the
  32  * software without specific, written prior permission.  M.I.T. makes
  33  * no representations about the suitability of this software for any
  34  * purpose.  It is provided "as is" without express or implied
  35  * warranty.
  36  *
  37  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
  38  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
  39  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  40  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
  41  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  44  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  46  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  48  * SUCH DAMAGE.
  49  *
  50  */
  51
  52 #ifndef _NET_HOSTCACHE_H
  53 #define _NET_HOSTCACHE_H        1
  54
  55 /*
  56  * This file defines the interface between network protocols and
  57  * the cache of host-specific information maintained by the kernel.
  58  * The generic interface takes care of inserting and deleting entries,
  59  * maintaining mutual exclusion, and enforcing policy constraint on the
  60  * size of the cache and the maximum age of its entries.
  61  * It replaces an earlier scheme which overloaded the routing table
  62  * for this purpose, and should be significantly more efficient
  63  * at performing most operations.  (It does keep a route to each
  64  * entry in the cache.)  Most protocols will want to define a
  65  * structure which begins with `struct hcentry' so that they
  66  * can keep additional, protocol-specific information in it.
  67  */
  68
  69 #include <sys/queue.h>
  70
  71 struct hcentry {
  72         LIST_ENTRY(hcentry) hc_link;
  73         struct  timeval hc_idlesince;   /* time last ref dropped */
  74         struct  sockaddr *hc_host;      /* address of this entry's host */
  75         struct  rtentry *hc_rt;         /* route to get there */
  76         /* struct nexthop *hc_nh; */
  77         int     hc_refcnt;              /* reference count */
  78         struct  hctable *hc_hct;        /* back ref to table */
  79 };
  80
  81 struct hccallback {
  82         u_long  (*hccb_hash)(struct sockaddr *, u_long);
  83         int     (*hccb_delete)(struct hcentry *);
  84         u_long  (*hccb_bump)(u_long);
  85 };
  86
  87 LIST_HEAD(hchead, hcentry);
  88
  89 struct hctable {
  90         u_long  hct_nentries;
  91         u_long  hct_active;
  92         u_long  hct_idle;
  93         struct  hchead *hct_heads;
  94         struct  hccallback *hct_cb;
  95         int     hct_primes;
  96 };
  97
  98 #ifdef KERNEL
  99
 100 #ifdef MALLOC_DECLARE
 101 MALLOC_DECLARE(M_HOSTCACHE);
 102 #endif
 103 /*
 104  * The table-modification functions must be called from user mode, as
 105  * they may block waiting for memory and/or locks.
 106  */
 107 int     hc_init(int af, struct hccallback *hccb, int init_nelem, int primes);
 108 struct  hcentry *hc_get(struct sockaddr *sa);
 109 void    hc_ref(struct hcentry *hc);
 110 void    hc_rele(struct hcentry *hc);
 111 int     hc_insert(struct hcentry *hc);
 112 int     hc_delete(struct hcentry *hc);
 113 #endif /* KERNEL */
 114
 115 #endif /* _NET_HOSTCACHE_H */