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  
      18  #include <sys/types.h>
      19  
      20  #include <netinet/in.h>
      21  #include <arpa/nameser.h>
      22  
      23  #include <errno.h>
      24  #include <resolv.h>
      25  #include <string.h>
      26  #include <ctype.h>
      27  #include <stdlib.h>
      28  #include <limits.h>
      29  
      30  # define SPRINTF(x) ((size_t)sprintf x)
      31  
      32  /* Forward. */
      33  
      34  static int		labellen(const u_char *);
      35  
      36  /* Public. */
      37  
      38  /*%
      39   *	Convert a network strings labels into all lowercase.
      40   *
      41   * return:
      42   *\li	Number of bytes written to buffer, or -1 (with errno set)
      43   *
      44   * notes:
      45   *\li	Enforces label and domain length limits.
      46   */
      47  
      48  int
      49  ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
      50  {
      51  	const u_char *cp;
      52  	u_char *dn, *eom;
      53  	u_char c;
      54  	u_int n;
      55  	int l;
      56  
      57  	cp = src;
      58  	dn = dst;
      59  	eom = dst + dstsiz;
      60  
      61  	if (dn >= eom) {
      62  		__set_errno (EMSGSIZE);
      63  		return (-1);
      64  	}
      65  	while ((n = *cp++) != 0) {
      66  		if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
      67  			/* Some kind of compression pointer. */
      68  			__set_errno (EMSGSIZE);
      69  			return (-1);
      70  		}
      71  		*dn++ = n;
      72  		if ((l = labellen(cp - 1)) < 0) {
      73  			__set_errno (EMSGSIZE);
      74  			return (-1);
      75  		}
      76  		if (dn + l >= eom) {
      77  			__set_errno (EMSGSIZE);
      78  			return (-1);
      79  		}
      80  		for ((void)NULL; l > 0; l--) {
      81  			c = *cp++;
      82  			if (isupper(c))
      83  				*dn++ = tolower(c);
      84  			else
      85  				*dn++ = c;
      86  		}
      87  	}
      88  	*dn++ = '\0';
      89  	return (dn - dst);
      90  }
      91  
      92  /*%
      93   * Reset dnptrs so that there are no active references to pointers at or
      94   * after src.
      95   */
      96  void
      97  ns_name_rollback(const u_char *src, const u_char **dnptrs,
      98  		 const u_char **lastdnptr)
      99  {
     100  	while (dnptrs < lastdnptr && *dnptrs != NULL) {
     101  		if (*dnptrs >= src) {
     102  			*dnptrs = NULL;
     103  			break;
     104  		}
     105  		dnptrs++;
     106  	}
     107  }
     108  
     109  /* Private. */
     110  
     111  /* Return the length of the encoded label starting at LP, or -1 for
     112     compression references and extended label types.  */
     113  static int
     114  labellen (const unsigned char *lp)
     115  {
     116    if (*lp <= 63)
     117      return *lp;
     118    return -1;
     119  }
     120  
     121  /*! \file */