glibc/resolv/inet_pton.c

/*
 * Copyright (c) 1996,1999 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <ctype.h>
#include <string.h>
#include <errno.h>

static int inet_pton4 (const char *src, unsigned char *dst);
static int inet_pton6 (const char *src, unsigned char *dst);

/* Convert from presentation format (which usually means ASCII printable)
 * to network format (which is usually some kind of binary format).
 *
 * return:
 *      1 if the address was valid for the specified address family
 *      0 if the address wasn't valid (`dst' is untouched in this case)
 *      -1 if some other error occurred (`dst' is untouched in this case, too)
 * author:
 *      Paul Vixie, 1996.
 */
int
__inet_pton (int af, const char *src, void *dst)
{
  switch (af)
    {
    case AF_INET:
      return inet_pton4 (src, dst);
    case AF_INET6:
      return inet_pton6 (src, dst);
    default:
      __set_errno (EAFNOSUPPORT);
      return -1;
    }
}
libc_hidden_def (__inet_pton)
weak_alias (__inet_pton, inet_pton)
libc_hidden_weak (inet_pton)

/* Like inet_atonbut without all the hexadecimal, octal and shorthand.
 *
 * return:
 *      1 if `src' is a valid dotted quad, else 0.
 * notice:
 *      does not touch `dst' unless it's returning 1.
 * author:
 *      Paul Vixie, 1996.
 */
static int
inet_pton4 (const char *src, unsigned char *dst)
{
  int saw_digit, octets, ch;
  unsigned char tmp[NS_INADDRSZ], *tp;

  saw_digit = 0;
  octets = 0;
  *(tp = tmp) = 0;
  while ((ch = *src++) != '\0')
    {
      if (ch >= '0' && ch <= '9')
        {
          unsigned int new = *tp * 10 + (ch - '0');

          if (saw_digit && *tp == 0)
            return 0;
          if (new > 255)
            return 0;
          *tp = new;
          if (! saw_digit)
            {
              if (++octets > 4)
                return 0;
              saw_digit = 1;
            }
        }
      else if (ch == '.' && saw_digit)
        {
          if (octets == 4)
            return 0;
          *++tp = 0;
          saw_digit = 0;
        }
      else
        return 0;
    }
  if (octets < 4)
    return 0;
  memcpy (dst, tmp, NS_INADDRSZ);
  return 1;
}

/* Cconvert presentation level address to network order binary form.
 *
 * return:
 *      1 if `src' is a valid [RFC1884 2.2] address, else 0.
 * notice:
 *      (1) does not touch `dst' unless it's returning 1.
 *      (2) :: in a full address is silently ignored.
 * credit:
 *      inspired by Mark Andrews.
 * author:
 *      Paul Vixie, 1996.
 */
static int
inet_pton6 (const char *src, unsigned char *dst)
{
  static const char xdigits[] = "0123456789abcdef";
  unsigned char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
  const char *curtok;
  int ch, saw_xdigit;
  unsigned int val;

  tp = memset (tmp, '\0', NS_IN6ADDRSZ);
  endp = tp + NS_IN6ADDRSZ;
  colonp = NULL;
  /* Leading :: requires some special handling.  */
  if (*src == ':')
    if (*++src != ':')
      return 0;
  curtok = src;
  saw_xdigit = 0;
  val = 0;
  while ((ch = tolower (*src++)) != '\0')
    {
      const char *pch;

      pch = strchr (xdigits, ch);
      if (pch != NULL)
	{
	  val <<= 4;
	  val |= (pch - xdigits);
	  if (val > 0xffff)
	    return 0;
	  saw_xdigit = 1;
	  continue;
	}
      if (ch == ':')
	{
	  curtok = src;
	  if (!saw_xdigit)
	    {
	      if (colonp)
		return 0;
	      colonp = tp;
	      continue;
	    }
	  else if (*src == '\0')
	    {
	      return 0;
	    }
	  if (tp + NS_INT16SZ > endp)
	    return 0;
	  *tp++ = (unsigned char) (val >> 8) & 0xff;
	  *tp++ = (unsigned char) val & 0xff;
	  saw_xdigit = 0;
	  val = 0;
	  continue;
	}
      if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
	  inet_pton4 (curtok, tp) > 0)
	{
	  tp += NS_INADDRSZ;
	  saw_xdigit = 0;
	  break;  /* '\0' was seen by inet_pton4.  */
	}
      return 0;
    }
  if (saw_xdigit)
    {
      if (tp + NS_INT16SZ > endp)
	return 0;
      *tp++ = (unsigned char) (val >> 8) & 0xff;
      *tp++ = (unsigned char) val & 0xff;
    }
  if (colonp != NULL)
    {
      /*
       * Since some memmove's erroneously fail to handle
       * overlapping regions, we'll do the shift by hand.
       */
      const int n = tp - colonp;
      int i;

      if (tp == endp)
	return 0;
      for (i = 1; i <= n; i++)
	{
	  endp[- i] = colonp[n - i];
	  colonp[n - i] = 0;
	}
      tp = endp;
    }
  if (tp != endp)
    return 0;
  memcpy (dst, tmp, NS_IN6ADDRSZ);
  return 1;
}