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        best.len = 0;
 102        cur.base = -1;
 103        cur.len = 0;
 104        for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 105                if (words[i] == 0) {
 106                        if (cur.base == -1)
 107                                cur.base = i, cur.len = 1;
 108                        else
 109                                cur.len++;
 110                } else {
 111                        if (cur.base != -1) {
 112                                if (best.base == -1 || cur.len > best.len)
 113                                        best = cur;
 114                                cur.base = -1;
 115                        }
 116                }
 117        }
 118        if (cur.base != -1) {
 119                if (best.base == -1 || cur.len > best.len)
 120                        best = cur;
 121        }
 122        if (best.base != -1 && best.len < 2)
 123                best.base = -1;
 124
 125        /*
 126         * Format the result.
 127         */
 128        tp = tmp;
 129        for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 130                /* Are we inside the best run of 0x00's? */
 131                if (best.base != -1 && i >= best.base &&
 132                    i < (best.base + best.len)) {
 133                        if (i == best.base)
 134                                *tp++ = ':';
 135                        continue;
 136                }
 137                /* Are we following an initial run of 0x00s or any real hex? */
 138                if (i != 0)
 139                        *tp++ = ':';
 140                /* Is this address an encapsulated IPv4? */
 141                if (i == 6 && best.base == 0 &&
 142                    (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 143                        if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 144                                return (NULL);
 145                        tp += strlen(tp);
 146                        break;
 147                }
 148                tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);
 149        }
 150        /* Was it a trailing run of 0x00's? */
 151        if (best.base != -1 && (best.base + best.len) ==
 152            (NS_IN6ADDRSZ / NS_INT16SZ))
 153                *tp++ = ':';
 154        *tp++ = '\0';
 155
 156        /*
 157         * Check for overflow, copy, and we're done.
 158         */
 159        if ((size_t)(tp - tmp) > size) {
 160                errno = ENOSPC;
 161                return (NULL);
 162        }
 163        strcpy(dst, tmp);
 164        return (dst);
 165}
 166#endif
 167
 168/* char *
 169 * inet_ntop(af, src, dst, size)
 170 *      convert a network format address to presentation format.
 171 * return:
 172 *      pointer to presentation format address (`dst'), or NULL (see errno).
 173 * author:
 174 *      Paul Vixie, 1996.
 175 */
 176const char *
 177inet_ntop(int af, const void *src, char *dst, size_t size)
 178{
 179        switch (af) {
 180        case AF_INET:
 181                return (inet_ntop4(src, dst, size));
 182#ifndef NO_IPV6
 183        case AF_INET6:
 184                return (inet_ntop6(src, dst, size));
 185#endif
 186        default:
 187                errno = EAFNOSUPPORT;
 188                return (NULL);
 189        }
 190        /* NOTREACHED */
 191}