usr/src/lib/libsocket/inet/inet6_rthdr.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 2003 Sun Microsystems, Inc.
  24  * All rights reserved.  Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 /*
  30  * This code is conformant to revision 7 of 2292bis.  Some of these functions
  31  * were provided (named inet6_rthdr_) in a very similar form in RFC 2292.
  32  * The RFC 2292 variants are not supported.
  33  */
  34
  35 #include <stdio.h>
  36 #include <ctype.h>
  37 #include <string.h>
  38 #include <stdlib.h>
  39 #include <sys/types.h>
  40 #include <sys/socket.h>
  41 #include <netinet/in.h>
  42 #include <netinet/ip6.h>
  43 #include <unistd.h>
  44 #include <errno.h>
  45
  46 #define MAX_RTHDR0_SEGMENTS 127
  47
  48 /*
  49  * Return amount of space needed to hold N segments for the specified
  50  * routing type. Does NOT include space for cmsghdr.
  51  */
  52 socklen_t
  53 inet6_rth_space(int type, int segments)
  54 {
  55         if (type != IPV6_RTHDR_TYPE_0 || segments < 0 ||
  56             segments > MAX_RTHDR0_SEGMENTS)
  57                 return (0);
  58
  59         return (sizeof (struct ip6_rthdr0) +
  60             segments * sizeof (struct in6_addr));
  61 }
  62
  63 /*
  64  * Initializes rthdr structure. Verifies the segments against the length of
  65  * the buffer.
  66  * Note that a routing header can only hold 127 segments since the length field
  67  * in the header is just a byte.
  68  */
  69 void *
  70 inet6_rth_init(void *bp, socklen_t bp_len, int type, int segments)
  71 {
  72         struct ip6_rthdr0 *rthdr;
  73
  74         if (type != IPV6_RTHDR_TYPE_0 || segments < 0 ||
  75             segments > MAX_RTHDR0_SEGMENTS)
  76                 return (NULL);
  77
  78         if (bp_len < sizeof (struct ip6_rthdr0) +
  79             segments * sizeof (struct in6_addr))
  80                 return (NULL);
  81
  82         rthdr = (struct ip6_rthdr0 *)bp;
  83         rthdr->ip6r0_nxt = 0;
  84         rthdr->ip6r0_len = (segments * 2);
  85         rthdr->ip6r0_type = type;
  86         rthdr->ip6r0_segleft = 0;       /* Incremented by rthdr_add */
  87         *(uint32_t *)&rthdr->ip6r0_reserved = 0;
  88         return (bp);
  89 }
  90
  91 /*
  92  * Add one more address to the routing header. Fails when there is no more
  93  * room.
  94  */
  95 int
  96 inet6_rth_add(void *bp, const struct in6_addr *addr)
  97 {
  98         struct ip6_rthdr0 *rthdr;
  99         struct in6_addr *addrs;
 100
 101         rthdr = (struct ip6_rthdr0 *)bp;
 102         if ((rthdr->ip6r0_segleft + 1) * 2 > rthdr->ip6r0_len) {
 103                 /* Not room for one more */
 104                 return (-1);
 105         }
 106         addrs = (struct in6_addr *)((char *)rthdr + sizeof (*rthdr));
 107         addrs[rthdr->ip6r0_segleft++] = *addr;
 108         return (0);
 109 }
 110
 111 /*
 112  * Reverse a source route. Both arguments can point to the same buffer.
 113  */
 114 int
 115 inet6_rth_reverse(const void *in, void *out)
 116 {
 117         struct ip6_rthdr0 *rtin, *rtout;
 118         int i, segments;
 119         struct in6_addr tmp;
 120         struct in6_addr *rtout_addrs;
 121         struct in6_addr *rtin_addrs;
 122
 123         rtin = (struct ip6_rthdr0 *)in;
 124         rtout = (struct ip6_rthdr0 *)out;
 125
 126         if (rtout->ip6r0_type != 0 || rtin->ip6r0_type != 0 ||
 127             rtout->ip6r0_len > MAX_RTHDR0_SEGMENTS * 2 ||
 128             rtin->ip6r0_len > MAX_RTHDR0_SEGMENTS * 2 ||
 129             rtout->ip6r0_len != rtin->ip6r0_len)
 130                 return (-1);
 131
 132         segments = rtin->ip6r0_len / 2;
 133         rtout_addrs = (struct in6_addr *)((char *)rtout + sizeof (*rtout));
 134         rtin_addrs = (struct in6_addr *)((char *)rtin + sizeof (*rtin));
 135         for (i = 0; i < (segments + 1)/2; i++) {
 136                 tmp = rtin_addrs[i];
 137                 rtout_addrs[i] = rtin_addrs[segments - 1 - i];
 138                 rtout_addrs[segments - 1 - i] = tmp;
 139         }
 140         rtout->ip6r0_segleft = segments;
 141         return (0);
 142 }
 143
 144 /*
 145  * Return the number of segments in the routing header.
 146  */
 147 int
 148 inet6_rth_segments(const void *bp)
 149 {
 150         struct ip6_rthdr0 *rthdr;
 151
 152         rthdr = (struct ip6_rthdr0 *)bp;
 153         if (rthdr->ip6r0_type == 0) {
 154                 if (rthdr->ip6r0_len > MAX_RTHDR0_SEGMENTS * 2) {
 155                         return (-1);
 156                 } else {
 157                         return (rthdr->ip6r0_len / 2);
 158                 }
 159         } else {
 160                 return (-1);
 161         }
 162 }
 163
 164 /*
 165  * Return a pointer to an element in the source route.
 166  * This uses the C convention for index [0, size-1].
 167  */
 168 struct in6_addr *
 169 inet6_rth_getaddr(const void *bp, int index)
 170 {
 171         struct ip6_rthdr0 *rthdr;
 172         struct in6_addr *rv;
 173
 174         rthdr = (struct ip6_rthdr0 *)bp;
 175         if (index >= rthdr->ip6r0_len/2 || index < 0)
 176                 return (NULL);
 177
 178         rv = (struct in6_addr *)((char *)rthdr + sizeof (*rthdr));
 179         return (&rv[index]);
 180 }