resolv/ns_name_pton.c

   1 /* Convert a DNS domain name from presentation to wire format.
   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
  18 #include <arpa/nameser.h>
  19 #include <errno.h>
  20 #include <shlib-compat.h>
  21
  22 /* Converts an ASCII string into an encoded domain name as per
  23    RFC1035.  Returns -1 if it fails, 1 if string was fully qualified,
  24    0 is string was not fully qualified.  Enforces label and domain
  25    length limits.  */
  26 int
  27 ___ns_name_pton (const char *src, unsigned char *dst, size_t dstsiz)
  28 {
  29   unsigned char *label, *bp, *eom;
  30   int c, n, escaped;
  31
  32   escaped = 0;
  33   bp = dst;
  34   eom = dst + dstsiz;
  35   label = bp++;
  36
  37   while ((c = *src++) != 0)
  38     {
  39       if (escaped)
  40         {
  41           if ('0' <= c && c <= '9')
  42             {
  43               n = (c - '0') * 100;
  44               if ((c = *src++) == 0 || c < '0' || c > '9')
  45                 {
  46                   __set_errno (EMSGSIZE);
  47                   return -1;
  48                 }
  49               n += (c - '0') * 10;
  50               if ((c = *src++) == 0 || c < '0' || c > '9')
  51                 {
  52                   __set_errno (EMSGSIZE);
  53                   return -1;
  54                 }
  55               n += c - '0';
  56               if (n > 255)
  57                 {
  58                   __set_errno (EMSGSIZE);
  59                   return -1;
  60                 }
  61               c = n;
  62             }
  63           escaped = 0;
  64         }
  65       else if (c == '\\')
  66         {
  67           escaped = 1;
  68           continue;
  69         }
  70       else if (c == '.')
  71         {
  72           c = (bp - label - 1);
  73           if ((c & NS_CMPRSFLGS) != 0) /* Label too big.  */
  74             {
  75               __set_errno (EMSGSIZE);
  76               return -1;
  77             }
  78           if (label >= eom)
  79             {
  80               __set_errno (EMSGSIZE);
  81               return -1;
  82             }
  83           *label = c;
  84           /* Fully qualified ? */
  85           if (*src == '\0')
  86             {
  87               if (c != 0)
  88                 {
  89                   if (bp >= eom)
  90                     {
  91                       __set_errno (EMSGSIZE);
  92                       return -1;
  93                     }
  94                   *bp++ = '\0';
  95                 }
  96               if ((bp - dst) > MAXCDNAME)
  97                 {
  98                   __set_errno (EMSGSIZE);
  99                   return -1;
 100                 }
 101               return 1;
 102             }
 103           if (c == 0 || *src == '.')
 104             {
 105               __set_errno (EMSGSIZE);
 106               return -1;
 107             }
 108           label = bp++;
 109           continue;
 110         }
 111       if (bp >= eom)
 112         {
 113           __set_errno (EMSGSIZE);
 114           return -1;
 115         }
 116       *bp++ = (unsigned char) c;
 117     }
 118   if (escaped)                  /* Trailing backslash.  */
 119     {
 120       __set_errno (EMSGSIZE);
 121       return -1;
 122     }
 123   c = (bp - label - 1);
 124   if ((c & NS_CMPRSFLGS) != 0)  /* Label too big.  */
 125     {
 126       __set_errno (EMSGSIZE);
 127       return -1;
 128     }
 129   if (label >= eom)
 130     {
 131       __set_errno (EMSGSIZE);
 132       return -1;
 133     }
 134   *label = c;
 135   if (c != 0)
 136     {
 137       if (bp >= eom)
 138         {
 139           __set_errno (EMSGSIZE);
 140           return -1;
 141         }
 142       *bp++ = 0;
 143     }
 144   if ((bp - dst) > MAXCDNAME)   /* src too big.  */
 145     {
 146       __set_errno (EMSGSIZE);
 147       return -1;
 148     }
 149   return 0;
 150 }
 151 versioned_symbol (libc, ___ns_name_pton, ns_name_pton, GLIBC_2_34);
 152 versioned_symbol (libc, ___ns_name_pton, __ns_name_pton, GLIBC_PRIVATE);
 153 libc_hidden_ver (___ns_name_pton, __ns_name_pton)
 154
 155 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_9, GLIBC_2_34)
 156 compat_symbol (libresolv, ___ns_name_pton, ns_name_pton, GLIBC_2_9);
 157 #endif