src/kits/network/netresolv/inet/inet_net_ntop.c

   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 <sys/cdefs.h>
  19 #if defined(LIBC_SCCS) && !defined(lint)
  20 #ifdef notdef
  21 static const char rcsid[] = "Id: inet_net_ntop.c,v 1.1.2.1 2002/08/02 02:17:21 marka Exp ";
  22 #else
  23 __RCSID("$NetBSD: inet_net_ntop.c,v 1.4 2017/05/09 02:56:44 maya Exp $");
  24 #endif
  25 #endif
  26
  27 #include "port_before.h"
  28
  29 #include <sys/types.h>
  30 #include <sys/socket.h>
  31 #include <netinet/in.h>
  32 #include <arpa/inet.h>
  33
  34 #include <errno.h>
  35 #include <stdio.h>
  36 #include <string.h>
  37 #include <stdlib.h>
  38
  39 #include "port_after.h"
  40
  41 #ifdef __weak_alias
  42 __weak_alias(inet_net_ntop,_inet_net_ntop)
  43 #endif
  44
  45 #ifdef SPRINTF_CHAR
  46 # define SPRINTF(x) strlen(sprintf/**/x)
  47 #else
  48 # define SPRINTF(x) sprintf x
  49 #endif
  50
  51 static char *   inet_net_ntop_ipv4(const u_char *src, int bits,
  52                                         char *dst, size_t size);
  53 static char *   inet_net_ntop_ipv6(const u_char *src, int bits,
  54                                         char *dst, size_t size);
  55
  56 /*
  57  * char *
  58  * inet_net_ntop(af, src, bits, dst, size)
  59  *      convert network number from network to presentation format.
  60  *      generates CIDR style result always.
  61  * return:
  62  *      pointer to dst, or NULL if an error occurred (check errno).
  63  * author:
  64  *      Paul Vixie (ISC), July 1996
  65  */
  66 char *
  67 inet_net_ntop(int af, const void *src, int bits, char *dst, size_t size)
  68 {
  69         switch (af) {
  70         case AF_INET:
  71                 return (inet_net_ntop_ipv4(src, bits, dst, size));
  72         case AF_INET6:
  73                 return (inet_net_ntop_ipv6(src, bits, dst, size));
  74         default:
  75                 errno = EAFNOSUPPORT;
  76                 return (NULL);
  77         }
  78 }
  79
  80 /*
  81  * static char *
  82  * inet_net_ntop_ipv4(src, bits, dst, size)
  83  *      convert IPv4 network number from network to presentation format.
  84  *      generates CIDR style result always.
  85  * return:
  86  *      pointer to dst, or NULL if an error occurred (check errno).
  87  * note:
  88  *      network byte order assumed.  this means 192.5.5.240/28 has
  89  *      0b11110000 in its fourth octet.
  90  * author:
  91  *      Paul Vixie (ISC), July 1996
  92  */
  93 static char *
  94 inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
  95 {
  96         char *odst = dst;
  97         char *t;
  98         u_int m;
  99         int b;
 100
 101         if (bits < 0 || bits > 32) {
 102                 errno = EINVAL;
 103                 return (NULL);
 104         }
 105
 106         if (bits == 0) {
 107                 if (size < sizeof "0")
 108                         goto emsgsize;
 109                 *dst++ = '0';
 110                 size--;
 111                 *dst = '\0';
 112         }
 113
 114         /* Format whole octets. */
 115         for (b = bits / 8; b > 0; b--) {
 116                 if (size <= sizeof "255.")
 117                         goto emsgsize;
 118                 t = dst;
 119                 dst += SPRINTF((dst, "%u", *src++));
 120                 if (b > 1) {
 121                         *dst++ = '.';
 122                         *dst = '\0';
 123                 }
 124                 size -= (size_t)(dst - t);
 125         }
 126
 127         /* Format partial octet. */
 128         b = bits % 8;
 129         if (b > 0) {
 130                 if (size <= sizeof ".255")
 131                         goto emsgsize;
 132                 t = dst;
 133                 if (dst != odst)
 134                         *dst++ = '.';
 135                 m = ((1 << b) - 1) << (8 - b);
 136                 dst += SPRINTF((dst, "%u", *src & m));
 137                 size -= (size_t)(dst - t);
 138         }
 139
 140         /* Format CIDR /width. */
 141         if (size <= sizeof "/32")
 142                 goto emsgsize;
 143         dst += SPRINTF((dst, "/%u", bits));
 144         return (odst);
 145
 146  emsgsize:
 147         errno = EMSGSIZE;
 148         return (NULL);
 149 }
 150
 151 /*
 152  * static char *
 153  * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
 154  *      convert IPv6 network number from network to presentation format.
 155  *      generates CIDR style result always. Picks the shortest representation
 156  *      unless the IP is really IPv4.
 157  *      always prints specified number of bits (bits).
 158  * return:
 159  *      pointer to dst, or NULL if an error occurred (check errno).
 160  * note:
 161  *      network byte order assumed.  this means 192.5.5.240/28 has
 162  *      0x11110000 in its fourth octet.
 163  * author:
 164  *      Vadim Kogan (UCB), June 2001
 165  *  Original version (IPv4) by Paul Vixie (ISC), July 1996
 166  */
 167
 168 static char *
 169 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size)
 170 {
 171         u_int   m;
 172         int     b;
 173         size_t  p;
 174         size_t  zero_s, zero_l, tmp_zero_s, tmp_zero_l;
 175         size_t  i;
 176         int     is_ipv4 = 0;
 177         unsigned char inbuf[16];
 178         char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
 179         char    *cp;
 180         size_t  words;
 181         u_char  *s;
 182
 183         if (bits < 0 || bits > 128) {
 184                 errno = EINVAL;
 185                 return (NULL);
 186         }
 187
 188         cp = outbuf;
 189
 190         if (bits == 0) {
 191                 *cp++ = ':';
 192                 *cp++ = ':';
 193                 *cp = '\0';
 194         } else {
 195                 /* Copy src to private buffer.  Zero host part. */
 196                 p = (bits + 7) / 8;
 197                 memcpy(inbuf, src, p);
 198                 memset(inbuf + p, 0, 16 - p);
 199                 b = bits % 8;
 200                 if (b != 0) {
 201                         m = ~0u << (8 - b);
 202                         inbuf[p-1] &= m;
 203                 }
 204
 205                 s = inbuf;
 206
 207                 /* how many words need to be displayed in output */
 208                 words = (bits + 15) / 16;
 209                 if (words == 1)
 210                         words = 2;
 211
 212                 /* Find the longest substring of zero's */
 213                 zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
 214                 for (i = 0; i < (words * 2); i += 2) {
 215                         if ((s[i] | s[i+1]) == 0) {
 216                                 if (tmp_zero_l == 0)
 217                                         tmp_zero_s = i / 2;
 218                                 tmp_zero_l++;
 219                         } else {
 220                                 if (tmp_zero_l && zero_l < tmp_zero_l) {
 221                                         zero_s = tmp_zero_s;
 222                                         zero_l = tmp_zero_l;
 223                                         tmp_zero_l = 0;
 224                                 }
 225                         }
 226                 }
 227
 228                 if (tmp_zero_l && zero_l < tmp_zero_l) {
 229                         zero_s = tmp_zero_s;
 230                         zero_l = tmp_zero_l;
 231                 }
 232
 233                 if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
 234                     ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
 235                     ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
 236                         is_ipv4 = 1;
 237
 238                 /* Format whole words. */
 239                 for (p = 0; p < words; p++) {
 240                         if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
 241                                 /* Time to skip some zeros */
 242                                 if (p == zero_s)
 243                                         *cp++ = ':';
 244                                 if (p == words - 1)
 245                                         *cp++ = ':';
 246                                 s++;
 247                                 s++;
 248                                 continue;
 249                         }
 250
 251                         if (is_ipv4 && p > 5 ) {
 252                                 *cp++ = (p == 6) ? ':' : '.';
 253                                 cp += SPRINTF((cp, "%u", *s++));
 254                                 /* we can potentially drop the last octet */
 255                                 if (p != 7 || bits > 120) {
 256                                         *cp++ = '.';
 257                                         cp += SPRINTF((cp, "%u", *s++));
 258                                 }
 259                         } else {
 260                                 if (cp != outbuf)
 261                                         *cp++ = ':';
 262                                 cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
 263                                 s += 2;
 264                         }
 265                 }
 266         }
 267         /* Format CIDR /width. */
 268         (void)SPRINTF((cp, "/%u", bits));
 269         if (strlen(outbuf) + 1 > size)
 270                 goto emsgsize;
 271         strcpy(dst, outbuf);
 272
 273         return (dst);
 274
 275 emsgsize:
 276         errno = EMSGSIZE;
 277         return (NULL);
 278 }
 279
 280 #undef inet_net_ntop
 281 #pragma weak inet_net_ntop = __inet_net_ntop