bsd/netinet/in_hostcache.c

   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 #include <sys/param.h>
  53 #include <sys/systm.h>
  54 #include <sys/malloc.h>
  55 #include <sys/socket.h>
  56 #include <sys/socketvar.h>
  57
  58 #include <net/hostcache.h>
  59 #include <net/if.h>
  60 #include <net/if_var.h>
  61 #include <net/route.h>
  62
  63 #include <netinet/in.h>
  64 #include <netinet/in_hostcache.h>
  65 #include <netinet/tcp.h>
  66 #include <netinet/tcp_timer.h>
  67 #include <netinet/tcp_var.h>
  68
  69 /*
  70  * Manage the IP per-host cache (really a thin veneer over the generic
  71  * per-host cache code).
  72  */
  73
  74 /* Look up an entry -- can be called from interrupt context. */
  75 struct in_hcentry *
  76 inhc_lookup(struct sockaddr_in *sin)
  77 {
  78         struct hcentry *hc;
  79
  80         hc = hc_get((struct sockaddr *)sin);
  81         return ((struct in_hcentry *)hc);
  82 }
  83
  84 /* Look up and possibly create an entry -- must be called from user mode. */
  85 struct in_hcentry *
  86 inhc_alloc(struct sockaddr_in *sin)
  87 {
  88         struct in_hcentry *inhc;
  89         struct rtentry *rt;
  90         int error;
  91         /* xxx mutual exclusion for smp */
  92
  93         inhc = inhc_lookup(sin);
  94         if (inhc != 0)
  95                 return inhc;
  96
  97         rt = rtalloc1(inhc->inhc_hc.hc_host, 1, 0);
  98         if (rt == 0)
  99                 return 0;
 100
 101         MALLOC(inhc, struct in_hcentry *, sizeof *inhc, M_HOSTCACHE, M_WAITOK);
 102         if (inhc == NULL)
 103                 retturn (ENOMEM);
 104         bzero(inhc, sizeof *inhc);
 105         inhc->inhc_hc.hc_host = dup_sockaddr((struct sockaddr *)sin, 1);
 106         if (in_broadcast(sin->sin_addr, rt->rt_ifp))
 107                 inhc->inhc_flags |= INHC_BROADCAST;
 108         else if (((struct sockaddr_in *)rt->rt_ifa->ifa_addr)->sin_addr.s_addr
 109                 == sin->sin_addr.s_addr)
 110                 inhc->inhc_flags |= INHC_LOCAL;
 111         else if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
 112                 inhc->inhc_flags |= INHC_MULTICAST;
 113         inhc->inhc_pmtu = rt->rt_rmx.rmx_mtu;
 114         inhc->inhc_recvpipe = rt->rt_rmx.rmx_recvpipe;
 115         inhc->inhc_sendpipe = rt->rt_rmx.rmx_sendpipe;
 116         inhc->inhc_ssthresh = rt->rt_rmx.rmx_ssthresh;
 117         if (rt->rt_rmx.rmx_locks & RTV_RTT)
 118                 inhc->inhc_rttmin = rt->rt_rmx.rmx_rtt
 119                         / (RTM_RTTUNIT / TCP_RTT_SCALE);
 120         inhc->inhc_hc.hc_rt = rt;
 121         error = hc_insert(&inhc->inhc_hc);
 122         if (error != 0) {
 123                 RTFREE(rt);
 124                 FREE(inhc, M_HOSTCACHE);
 125                 return 0;
 126         }
 127         /*
 128          * We don't return the structure directly because hc_get() needs
 129          * to be allowed to do its own processing.
 130          */
 131         return (inhc_lookup(sin));
 132 }
 133
 134 /*
 135  * This is Van Jacobson's hash function for IPv4 addresses.
 136  * It is designed to work with a power-of-two-sized hash table.
 137  */
 138 static u_long
 139 inhc_hash(struct sockaddr *sa, u_long nbuckets)
 140 {
 141         u_long ip;
 142
 143         ip = ((struct sockaddr_in *)sa)->sin_addr.s_addr;
 144         return ((ip ^ (ip >> 23) ^ (ip >> 17)) & ~(nbuckets - 1));
 145 }
 146
 147 /*
 148  * We don't need to do any special work... if there are no references,
 149  * as the caller has already ensured, then it's OK to kill.
 150  */
 151 static int
 152 inhc_delete(struct hcentry *hc)
 153 {
 154         return 0;
 155 }
 156
 157 /*
 158  * Return the next increment for the number of buckets in the hash table.
 159  * Zero means ``do not bump''.
 160  */
 161 static u_long
 162 inhc_bump(u_long oldsize)
 163 {
 164         if (oldsize < 512)
 165                 return (oldsize << 1);
 166         return 0;
 167 }
 168
 169 static struct hccallback inhc_cb = {
 170         inhc_hash, inhc_delete, inhc_bump
 171 };
 172
 173 int
 174 inhc_init(void)
 175 {
 176
 177         return (hc_init(AF_INET, &inhc_cb, 128, 0));
 178 }
 179