src/port/inet_net_ntop.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1996,1999 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  *
  17  *        src/port/inet_net_ntop.c
  18  */
  19
  20 #if defined(LIBC_SCCS) && !defined(lint)
  21 static const char rcsid[] = "Id: inet_net_ntop.c,v 1.1.2.2 2004/03/09 09:17:27 marka Exp $";
  22 #endif
  23
  24 #ifndef FRONTEND
  25 #include "postgres.h"
  26 #else
  27 #include "postgres_fe.h"
  28 #endif
  29
  30 #include <sys/socket.h>
  31 #include <netinet/in.h>
  32 #include <arpa/inet.h>
  33
  34 #ifndef FRONTEND
  35 #include "utils/inet.h"
  36 #else
  37 /*
  38  * In a frontend build, we can't include inet.h, but we still need to have
  39  * sensible definitions of these two constants.  Note that pg_inet_net_ntop()
  40  * assumes that PGSQL_AF_INET is equal to AF_INET.
  41  */
  42 #define PGSQL_AF_INET   (AF_INET + 0)
  43 #define PGSQL_AF_INET6  (AF_INET + 1)
  44 #endif
  45
  46
  47 #define NS_IN6ADDRSZ 16
  48 #define NS_INT16SZ 2
  49
  50 #ifdef SPRINTF_CHAR
  51 #define SPRINTF(x) strlen(sprintf/**/x)
  52 #else
  53 #define SPRINTF(x) ((size_t)sprintf x)
  54 #endif
  55
  56 static char *inet_net_ntop_ipv4(const u_char *src, int bits,
  57                                                                 char *dst, size_t size);
  58 static char *inet_net_ntop_ipv6(const u_char *src, int bits,
  59                                                                 char *dst, size_t size);
  60
  61
  62 /*
  63  * char *
  64  * pg_inet_net_ntop(af, src, bits, dst, size)
  65  *      convert host/network address from network to presentation format.
  66  *      "src"'s size is determined from its "af".
  67  * return:
  68  *      pointer to dst, or NULL if an error occurred (check errno).
  69  * note:
  70  *      192.5.5.1/28 has a nonzero host part, which means it isn't a network
  71  *      as called for by pg_inet_net_pton() but it can be a host address with
  72  *      an included netmask.
  73  * author:
  74  *      Paul Vixie (ISC), October 1998
  75  */
  76 char *
  77 pg_inet_net_ntop(int af, const void *src, int bits, char *dst, size_t size)
  78 {
  79         /*
  80          * We need to cover both the address family constants used by the PG inet
  81          * type (PGSQL_AF_INET and PGSQL_AF_INET6) and those used by the system
  82          * libraries (AF_INET and AF_INET6).  We can safely assume PGSQL_AF_INET
  83          * == AF_INET, but the INET6 constants are very likely to be different.
  84          */
  85         switch (af)
  86         {
  87                 case PGSQL_AF_INET:
  88                         return (inet_net_ntop_ipv4(src, bits, dst, size));
  89                 case PGSQL_AF_INET6:
  90 #if AF_INET6 != PGSQL_AF_INET6
  91                 case AF_INET6:
  92 #endif
  93                         return (inet_net_ntop_ipv6(src, bits, dst, size));
  94                 default:
  95                         errno = EAFNOSUPPORT;
  96                         return (NULL);
  97         }
  98 }
  99
 100 /*
 101  * static char *
 102  * inet_net_ntop_ipv4(src, bits, dst, size)
 103  *      convert IPv4 network address from network to presentation format.
 104  *      "src"'s size is determined from its "af".
 105  * return:
 106  *      pointer to dst, or NULL if an error occurred (check errno).
 107  * note:
 108  *      network byte order assumed.  this means 192.5.5.240/28 has
 109  *      0b11110000 in its fourth octet.
 110  * author:
 111  *      Paul Vixie (ISC), October 1998
 112  */
 113 static char *
 114 inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
 115 {
 116         char       *odst = dst;
 117         char       *t;
 118         int                     len = 4;
 119         int                     b;
 120
 121         if (bits < 0 || bits > 32)
 122         {
 123                 errno = EINVAL;
 124                 return (NULL);
 125         }
 126
 127         /* Always format all four octets, regardless of mask length. */
 128         for (b = len; b > 0; b--)
 129         {
 130                 if (size <= sizeof ".255")
 131                         goto emsgsize;
 132                 t = dst;
 133                 if (dst != odst)
 134                         *dst++ = '.';
 135                 dst += SPRINTF((dst, "%u", *src++));
 136                 size -= (size_t) (dst - t);
 137         }
 138
 139         /* don't print masklen if 32 bits */
 140         if (bits != 32)
 141         {
 142                 if (size <= sizeof "/32")
 143                         goto emsgsize;
 144                 dst += SPRINTF((dst, "/%u", bits));
 145         }
 146
 147         return (odst);
 148
 149 emsgsize:
 150         errno = EMSGSIZE;
 151         return (NULL);
 152 }
 153
 154 static int
 155 decoct(const u_char *src, int bytes, char *dst, size_t size)
 156 {
 157         char       *odst = dst;
 158         char       *t;
 159         int                     b;
 160
 161         for (b = 1; b <= bytes; b++)
 162         {
 163                 if (size <= sizeof "255.")
 164                         return (0);
 165                 t = dst;
 166                 dst += SPRINTF((dst, "%u", *src++));
 167                 if (b != bytes)
 168                 {
 169                         *dst++ = '.';
 170                         *dst = '\0';
 171                 }
 172                 size -= (size_t) (dst - t);
 173         }
 174         return (dst - odst);
 175 }
 176
 177 static char *
 178 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size)
 179 {
 180         /*
 181          * Note that int32_t and int16_t need only be "at least" large enough to
 182          * contain a value of the specified size.  On some systems, like Crays,
 183          * there is no such thing as an integer variable with 16 bits. Keep this
 184          * in mind if you think this function should have been coded to use
 185          * pointer overlays.  All the world's not a VAX.
 186          */
 187         char            tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"];
 188         char       *tp;
 189         struct
 190         {
 191                 int                     base,
 192                                         len;
 193         }                       best, cur;
 194         u_int           words[NS_IN6ADDRSZ / NS_INT16SZ];
 195         int                     i;
 196
 197         if ((bits < -1) || (bits > 128))
 198         {
 199                 errno = EINVAL;
 200                 return (NULL);
 201         }
 202
 203         /*
 204          * Preprocess: Copy the input (bytewise) array into a wordwise array. Find
 205          * the longest run of 0x00's in src[] for :: shorthanding.
 206          */
 207         memset(words, '\0', sizeof words);
 208         for (i = 0; i < NS_IN6ADDRSZ; i++)
 209                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 210         best.base = -1;
 211         cur.base = -1;
 212         best.len = 0;
 213         cur.len = 0;
 214         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++)
 215         {
 216                 if (words[i] == 0)
 217                 {
 218                         if (cur.base == -1)
 219                                 cur.base = i, cur.len = 1;
 220                         else
 221                                 cur.len++;
 222                 }
 223                 else
 224                 {
 225                         if (cur.base != -1)
 226                         {
 227                                 if (best.base == -1 || cur.len > best.len)
 228                                         best = cur;
 229                                 cur.base = -1;
 230                         }
 231                 }
 232         }
 233         if (cur.base != -1)
 234         {
 235                 if (best.base == -1 || cur.len > best.len)
 236                         best = cur;
 237         }
 238         if (best.base != -1 && best.len < 2)
 239                 best.base = -1;
 240
 241         /*
 242          * Format the result.
 243          */
 244         tp = tmp;
 245         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++)
 246         {
 247                 /* Are we inside the best run of 0x00's? */
 248                 if (best.base != -1 && i >= best.base &&
 249                         i < (best.base + best.len))
 250                 {
 251                         if (i == best.base)
 252                                 *tp++ = ':';
 253                         continue;
 254                 }
 255                 /* Are we following an initial run of 0x00s or any real hex? */
 256                 if (i != 0)
 257                         *tp++ = ':';
 258                 /* Is this address an encapsulated IPv4? */
 259                 if (i == 6 && best.base == 0 && (best.len == 6 ||
 260                                                                                  (best.len == 7 && words[7] != 0x0001) ||
 261                                                                                  (best.len == 5 && words[5] == 0xffff)))
 262                 {
 263                         int                     n;
 264
 265                         n = decoct(src + 12, 4, tp, sizeof tmp - (tp - tmp));
 266                         if (n == 0)
 267                         {
 268                                 errno = EMSGSIZE;
 269                                 return (NULL);
 270                         }
 271                         tp += strlen(tp);
 272                         break;
 273                 }
 274                 tp += SPRINTF((tp, "%x", words[i]));
 275         }
 276
 277         /* Was it a trailing run of 0x00's? */
 278         if (best.base != -1 && (best.base + best.len) ==
 279                 (NS_IN6ADDRSZ / NS_INT16SZ))
 280                 *tp++ = ':';
 281         *tp = '\0';
 282
 283         if (bits != -1 && bits != 128)
 284                 tp += SPRINTF((tp, "/%u", bits));
 285
 286         /*
 287          * Check for overflow, copy, and we're done.
 288          */
 289         if ((size_t) (tp - tmp) > size)
 290         {
 291                 errno = EMSGSIZE;
 292                 return (NULL);
 293         }
 294         strcpy(dst, tmp);
 295         return (dst);
 296 }