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 <errno.h>
  19#include <sys/types.h>
  20
  21#include "../git-compat-util.h"
  22
  23#include <stdio.h>
  24#include <string.h>
  25
  26#ifndef NS_INADDRSZ
  27#define NS_INADDRSZ     4
  28#endif
  29#ifndef NS_IN6ADDRSZ
  30#define NS_IN6ADDRSZ    16
  31#endif
  32#ifndef NS_INT16SZ
  33#define NS_INT16SZ      2
  34#endif
  35
  36/*
  37 * WARNING: Don't even consider trying to compile this on a system where
  38 * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  39 */
  40
  41/* const char *
  42 * inet_ntop4(src, dst, size)
  43 *      format an IPv4 address
  44 * return:
  45 *      `dst' (as a const)
  46 * notes:
  47 *      (1) uses no statics
  48 *      (2) takes a u_char* not an in_addr as input
  49 * author:
  50 *      Paul Vixie, 1996.
  51 */
  52static const char *
  53inet_ntop4(const u_char *src, char *dst, size_t size)
  54{
  55        static const char fmt[] = "%u.%u.%u.%u";
  56        char tmp[sizeof "255.255.255.255"];
  57        int nprinted;
  58
  59        nprinted = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
  60        if (nprinted < 0)
  61                return (NULL);  /* we assume "errno" was set by "snprintf()" */
  62        if ((size_t)nprinted > size) {
  63                errno = ENOSPC;
  64                return (NULL);
  65        }
  66        strcpy(dst, tmp);
  67        return (dst);
  68}
  69
  70#ifndef NO_IPV6
  71/* const char *
  72 * inet_ntop6(src, dst, size)
  73 *      convert IPv6 binary address into presentation (printable) format
  74 * author:
  75 *      Paul Vixie, 1996.
  76 */
  77static const char *
  78inet_ntop6(const u_char *src, char *dst, size_t size)
  79{
  80        /*
  81         * Note that int32_t and int16_t need only be "at least" large enough
  82         * to contain a value of the specified size.  On some systems, like
  83         * Crays, there is no such thing as an integer variable with 16 bits.
  84         * Keep this in mind if you think this function should have been coded
  85         * to use pointer overlays.  All the world's not a VAX.
  86         */
  87        char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
  88        struct { int base, len; } best, cur;
  89        unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
  90        int i;
  91
  92        /*
  93         * Preprocess:
  94         *      Copy the input (bytewise) array into a wordwise array.
  95         *      Find the longest run of 0x00's in src[] for :: shorthanding.
  96         */
  97        memset(words, '\0', sizeof words);
  98        for (i = 0; i < NS_IN6ADDRSZ; i++)
  99                words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 100        best.base = -1;
 101        cur.base = -1;
 102        for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 103                if (words[i] == 0) {
 104                        if (cur.base == -1)
 105                                cur.base = i, cur.len = 1;
 106                        else
 107                                cur.len++;
 108                } else {
 109                        if (cur.base != -1) {
 110                                if (best.base == -1 || cur.len > best.len)
 111                                        best = cur;
 112                                cur.base = -1;
 113                        }
 114                }
 115        }
 116        if (cur.base != -1) {
 117                if (best.base == -1 || cur.len > best.len)
 118                        best = cur;
 119        }
 120        if (best.base != -1 && best.len < 2)
 121                best.base = -1;
 122
 123        /*
 124         * Format the result.
 125         */
 126        tp = tmp;
 127        for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 128                /* Are we inside the best run of 0x00's? */
 129                if (best.base != -1 && i >= best.base &&
 130                    i < (best.base + best.len)) {
 131                        if (i == best.base)
 132                                *tp++ = ':';
 133                        continue;
 134                }
 135                /* Are we following an initial run of 0x00s or any real hex? */
 136                if (i != 0)
 137                        *tp++ = ':';
 138                /* Is this address an encapsulated IPv4? */
 139                if (i == 6 && best.base == 0 &&
 140                    (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 141                        if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 142                                return (NULL);
 143                        tp += strlen(tp);
 144                        break;
 145                }
 146                tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);
 147        }
 148        /* Was it a trailing run of 0x00's? */
 149        if (best.base != -1 && (best.base + best.len) ==
 150            (NS_IN6ADDRSZ / NS_INT16SZ))
 151                *tp++ = ':';
 152        *tp++ = '\0';
 153
 154        /*
 155         * Check for overflow, copy, and we're done.
 156         */
 157        if ((size_t)(tp - tmp) > size) {
 158                errno = ENOSPC;
 159                return (NULL);
 160        }
 161        strcpy(dst, tmp);
 162        return (dst);
 163}
 164#endif
 165
 166/* char *
 167 * inet_ntop(af, src, dst, size)
 168 *      convert a network format address to presentation format.
 169 * return:
 170 *      pointer to presentation format address (`dst'), or NULL (see errno).
 171 * author:
 172 *      Paul Vixie, 1996.
 173 */
 174const char *
 175inet_ntop(int af, const void *src, char *dst, size_t size)
 176{
 177        switch (af) {
 178        case AF_INET:
 179                return (inet_ntop4(src, dst, size));
 180#ifndef NO_IPV6
 181        case AF_INET6:
 182                return (inet_ntop6(src, dst, size));
 183#endif
 184        default:
 185                errno = EAFNOSUPPORT;
 186                return (NULL);
 187        }
 188        /* NOTREACHED */
 189}