resolv/inet_pton.c

   1 /* Copyright (C) 1996-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 /*
  19  * Copyright (c) 1996,1999 by Internet Software Consortium.
  20  *
  21  * Permission to use, copy, modify, and distribute this software for any
  22  * purpose with or without fee is hereby granted, provided that the above
  23  * copyright notice and this permission notice appear in all copies.
  24  *
  25  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  26  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  28  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  29  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  30  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  31  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  32  * SOFTWARE.
  33  */
  34
  35 #include <arpa/inet.h>
  36 #include <arpa/nameser.h>
  37 #include <ctype.h>
  38 #include <errno.h>
  39 #include <netinet/in.h>
  40 #include <resolv/resolv-internal.h>
  41 #include <string.h>
  42 #include <sys/socket.h>
  43 #include <sys/types.h>
  44
  45 static int inet_pton4 (const char *src, const char *src_end, u_char *dst);
  46 static int inet_pton6 (const char *src, const char *src_end, u_char *dst);
  47
  48 int
  49 __inet_pton_length (int af, const char *src, size_t srclen, void *dst)
  50 {
  51   switch (af)
  52     {
  53     case AF_INET:
  54       return inet_pton4 (src, src + srclen, dst);
  55     case AF_INET6:
  56       return inet_pton6 (src, src + srclen, dst);
  57     default:
  58       __set_errno (EAFNOSUPPORT);
  59       return -1;
  60     }
  61 }
  62 libc_hidden_def (__inet_pton_length)
  63
  64 /* Like __inet_pton_length, but use strlen (SRC) as the length of
  65    SRC.  */
  66 int
  67 __inet_pton (int af, const char *src, void *dst)
  68 {
  69   return __inet_pton_length (af, src, strlen (src), dst);
  70 }
  71 libc_hidden_def (__inet_pton)
  72 weak_alias (__inet_pton, inet_pton)
  73 libc_hidden_weak (inet_pton)
  74
  75 /* Like inet_aton but without all the hexadecimal, octal and shorthand
  76    (and trailing garbage is not ignored).  Return 1 if SRC is a valid
  77    dotted quad, else 0.  This function does not touch DST unless it's
  78    returning 1.
  79    Author: Paul Vixie, 1996.  */
  80 static int
  81 inet_pton4 (const char *src, const char *end, unsigned char *dst)
  82 {
  83   int saw_digit, octets, ch;
  84   unsigned char tmp[NS_INADDRSZ], *tp;
  85
  86   saw_digit = 0;
  87   octets = 0;
  88   *(tp = tmp) = 0;
  89   while (src < end)
  90     {
  91       ch = *src++;
  92       if (ch >= '0' && ch <= '9')
  93         {
  94           unsigned int new = *tp * 10 + (ch - '0');
  95
  96           if (saw_digit && *tp == 0)
  97             return 0;
  98           if (new > 255)
  99             return 0;
 100           *tp = new;
 101           if (! saw_digit)
 102             {
 103               if (++octets > 4)
 104                 return 0;
 105               saw_digit = 1;
 106             }
 107         }
 108       else if (ch == '.' && saw_digit)
 109         {
 110           if (octets == 4)
 111             return 0;
 112           *++tp = 0;
 113           saw_digit = 0;
 114         }
 115       else
 116         return 0;
 117     }
 118   if (octets < 4)
 119     return 0;
 120   memcpy (dst, tmp, NS_INADDRSZ);
 121   return 1;
 122 }
 123
 124 /* Return the value of CH as a hexadecimal digit, or -1 if it is a
 125    different type of character.  */
 126 static int
 127 hex_digit_value (char ch)
 128 {
 129   if ('0' <= ch && ch <= '9')
 130     return ch - '0';
 131   if ('a' <= ch && ch <= 'f')
 132     return ch - 'a' + 10;
 133   if ('A' <= ch && ch <= 'F')
 134     return ch - 'A' + 10;
 135   return -1;
 136 }
 137
 138 /* Convert presentation-level IPv6 address to network order binary
 139    form.  Return 1 if SRC is a valid [RFC1884 2.2] address, else 0.
 140    This function does not touch DST unless it's returning 1.
 141    Author: Paul Vixie, 1996.  Inspired by Mark Andrews.  */
 142 static int
 143 inet_pton6 (const char *src, const char *src_endp, unsigned char *dst)
 144 {
 145   unsigned char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
 146   const char *curtok;
 147   int ch;
 148   size_t xdigits_seen;  /* Number of hex digits since colon.  */
 149   unsigned int val;
 150
 151   tp = memset (tmp, '\0', NS_IN6ADDRSZ);
 152   endp = tp + NS_IN6ADDRSZ;
 153   colonp = NULL;
 154
 155   /* Leading :: requires some special handling.  */
 156   if (src == src_endp)
 157     return 0;
 158   if (*src == ':')
 159     {
 160       ++src;
 161       if (src == src_endp || *src != ':')
 162         return 0;
 163     }
 164
 165   curtok = src;
 166   xdigits_seen = 0;
 167   val = 0;
 168   while (src < src_endp)
 169     {
 170       ch = *src++;
 171       int digit = hex_digit_value (ch);
 172       if (digit >= 0)
 173         {
 174           if (xdigits_seen == 4)
 175             return 0;
 176           val <<= 4;
 177           val |= digit;
 178           if (val > 0xffff)
 179             return 0;
 180           ++xdigits_seen;
 181           continue;
 182         }
 183       if (ch == ':')
 184         {
 185           curtok = src;
 186           if (xdigits_seen == 0)
 187             {
 188               if (colonp)
 189                 return 0;
 190               colonp = tp;
 191               continue;
 192             }
 193           else if (src == src_endp)
 194             return 0;
 195           if (tp + NS_INT16SZ > endp)
 196             return 0;
 197           *tp++ = (unsigned char) (val >> 8) & 0xff;
 198           *tp++ = (unsigned char) val & 0xff;
 199           xdigits_seen = 0;
 200           val = 0;
 201           continue;
 202         }
 203       if (ch == '.' && ((tp + NS_INADDRSZ) <= endp)
 204           && inet_pton4 (curtok, src_endp, tp) > 0)
 205         {
 206           tp += NS_INADDRSZ;
 207           xdigits_seen = 0;
 208           break;  /* '\0' was seen by inet_pton4.  */
 209         }
 210       return 0;
 211     }
 212   if (xdigits_seen > 0)
 213     {
 214       if (tp + NS_INT16SZ > endp)
 215         return 0;
 216       *tp++ = (unsigned char) (val >> 8) & 0xff;
 217       *tp++ = (unsigned char) val & 0xff;
 218     }
 219   if (colonp != NULL)
 220     {
 221       /* Replace :: with zeros.  */
 222       if (tp == endp)
 223         /* :: would expand to a zero-width field.  */
 224         return 0;
 225       size_t n = tp - colonp;
 226       memmove (endp - n, colonp, n);
 227       memset (colonp, 0, endp - n - colonp);
 228       tp = endp;
 229     }
 230   if (tp != endp)
 231     return 0;
 232   memcpy (dst, tmp, NS_IN6ADDRSZ);
 233   return 1;
 234 }