Andrew's git - gitweb.git/blob - compat/inet

   1/*
   2 * Copyright (c) 1996-1999 by Internet Software Consortium.
   3 *
   4 * Permission to use, copy, modify, and distribute this software for any
   5 * purpose with or without fee is hereby granted, provided that the above
   6 * copyright notice and this permission notice appear in all copies.
   7 *
   8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15 * SOFTWARE.
  16 */
  17
  18#include "../git-compat-util.h"
  19
  20#ifndef NS_INADDRSZ
  21#define NS_INADDRSZ     4
  22#endif
  23#ifndef NS_IN6ADDRSZ
  24#define NS_IN6ADDRSZ    16
  25#endif
  26#ifndef NS_INT16SZ
  27#define NS_INT16SZ      2
  28#endif
  29
  30/*
  31 * WARNING: Don't even consider trying to compile this on a system where
  32 * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  33 */
  34
  35/* const char *
  36 * inet_ntop4(src, dst, size)
  37 *      format an IPv4 address
  38 * return:
  39 *      `dst' (as a const)
  40 * notes:
  41 *      (1) uses no statics
  42 *      (2) takes a u_char* not an in_addr as input
  43 * author:
  44 *      Paul Vixie, 1996.
  45 */
  46static const char *
  47inet_ntop4(const u_char *src, char *dst, size_t size)
  48{
  49        static const char fmt[] = "%u.%u.%u.%u";
  50        char tmp[sizeof "255.255.255.255"];
  51        int nprinted;
  52
  53        nprinted = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
  54        if (nprinted < 0)
  55                return (NULL);  /* we assume "errno" was set by "snprintf()" */
  56        if ((size_t)nprinted > size) {
  57                errno = ENOSPC;
  58                return (NULL);
  59        }
  60        strcpy(dst, tmp);
  61        return (dst);
  62}
  63
  64#ifndef NO_IPV6
  65/* const char *
  66 * inet_ntop6(src, dst, size)
  67 *      convert IPv6 binary address into presentation (printable) format
  68 * author:
  69 *      Paul Vixie, 1996.
  70 */
  71static const char *
  72inet_ntop6(const u_char *src, char *dst, size_t size)
  73{
  74        /*
  75         * Note that int32_t and int16_t need only be "at least" large enough
  76         * to contain a value of the specified size.  On some systems, like
  77         * Crays, there is no such thing as an integer variable with 16 bits.
  78         * Keep this in mind if you think this function should have been coded
  79         * to use pointer overlays.  All the world's not a VAX.
  80         */
  81        char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
  82        struct { int base, len; } best, cur;
  83        unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
  84        int i;
  85
  86        /*
  87         * Preprocess:
  88         *      Copy the input (bytewise) array into a wordwise array.
  89         *      Find the longest run of 0x00's in src[] for :: shorthanding.
  90         */
  91        memset(words, '\0', sizeof words);
  92        for (i = 0; i < NS_IN6ADDRSZ; i++)
  93                words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
  94        best.base = -1;
  95        best.len = 0;
  96        cur.base = -1;
  97        cur.len = 0;
  98        for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
  99                if (words[i] == 0) {
 100                        if (cur.base == -1)
 101                                cur.base = i, cur.len = 1;
 102                        else
 103                                cur.len++;
 104                } else {
 105                        if (cur.base != -1) {
 106                                if (best.base == -1 || cur.len > best.len)
 107                                        best = cur;
 108                                cur.base = -1;
 109                        }
 110                }
 111        }
 112        if (cur.base != -1) {
 113                if (best.base == -1 || cur.len > best.len)
 114                        best = cur;
 115        }
 116        if (best.base != -1 && best.len < 2)
 117                best.base = -1;
 118
 119        /*
 120         * Format the result.
 121         */
 122        tp = tmp;
 123        for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 124                /* Are we inside the best run of 0x00's? */
 125                if (best.base != -1 && i >= best.base &&
 126                    i < (best.base + best.len)) {
 127                        if (i == best.base)
 128                                *tp++ = ':';
 129                        continue;
 130                }
 131                /* Are we following an initial run of 0x00s or any real hex? */
 132                if (i != 0)
 133                        *tp++ = ':';
 134                /* Is this address an encapsulated IPv4? */
 135                if (i == 6 && best.base == 0 &&
 136                    (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 137                        if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 138                                return (NULL);
 139                        tp += strlen(tp);
 140                        break;
 141                }
 142                tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);
 143        }
 144        /* Was it a trailing run of 0x00's? */
 145        if (best.base != -1 && (best.base + best.len) ==
 146            (NS_IN6ADDRSZ / NS_INT16SZ))
 147                *tp++ = ':';
 148        *tp++ = '\0';
 149
 150        /*
 151         * Check for overflow, copy, and we're done.
 152         */
 153        if ((size_t)(tp - tmp) > size) {
 154                errno = ENOSPC;
 155                return (NULL);
 156        }
 157        strcpy(dst, tmp);
 158        return (dst);
 159}
 160#endif
 161
 162/* char *
 163 * inet_ntop(af, src, dst, size)
 164 *      convert a network format address to presentation format.
 165 * return:
 166 *      pointer to presentation format address (`dst'), or NULL (see errno).
 167 * author:
 168 *      Paul Vixie, 1996.
 169 */
 170const char *
 171inet_ntop(int af, const void *src, char *dst, size_t size)
 172{
 173        switch (af) {
 174        case AF_INET:
 175                return (inet_ntop4(src, dst, size));
 176#ifndef NO_IPV6
 177        case AF_INET6:
 178                return (inet_ntop6(src, dst, size));
 179#endif
 180        default:
 181                errno = EAFNOSUPPORT;
 182                return (NULL);
 183        }
 184        /* NOTREACHED */
 185}