text: static const char rcsid[] = "$Header: /proj/cvs/prod/libbind/dst/support.c,v 1.6 2005/10/11 00:10:13 marka Exp $";
  
  
  /*
   * Portions Copyright (c) 1995-1998 by Trusted Information Systems, Inc.
   *
   * 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 TRUSTED INFORMATION SYSTEMS
   * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL
   * TRUSTED INFORMATION SYSTEMS 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 THE SOFTWARE.
   */
  
  #include <port_before.h>
  
  #include <stdio.h>
  #include <unistd.h>
  #include <memory.h>
  #include <kits/support/String.h>
  #include <errno.h>
  #include <sys/stat.h>
  #include <netinet/in.h>
  #include <arpa/nameser.h>
  #include <resolv.h>
  
  #include <dst_internal.h>
  
  #include <port_after.h>
  
  /*%
   * dst_s_verify_str()
   *     Validate that the input string(*str) is at the head of the input
   *     buffer(**buf).  If so, move the buffer head pointer (*buf) to
   *     the first byte of data following the string(*str).
   * Parameters
   *     buf     Input buffer.
   *     str     Input string.
   * Return
   *	0       *str is not the head of **buff
   *	1       *str is the head of **buff, *buf is is advanced to
   *	the tail of **buf.
   */
  
  int
  dst_s_verify_str(const char **buf, const char *str)
  {
  	int b, s;
  	if (*buf == NULL)	/*%< error checks */
  		return (0);
  	if (str == NULL || *str == '\0')
  		return (1);
  
  	b = strlen(*buf);	/*%< get length of strings */
  	s = strlen(str);
  	if (s > b || strncmp(*buf, str, s))	/*%< check if same */
  		return (0);	/*%< not a match */
  	(*buf) += s;		/*%< advance pointer */
  	return (1);
  }
  
  /*%
   * dst_s_calculate_bits
   *     Given a binary number represented in a u_char[], determine
   *     the number of significant bits used.
   * Parameters
   *     str       An input character string containing a binary number.
   *     max_bits The maximum possible significant bits.
   * Return
   *     N       The number of significant bits in str.
   */
  
  int
  dst_s_calculate_bits(const u_char *str, const int max_bits)
  {
  	const u_char *p = str;
  	u_char i, j = 0x80;
  	int bits;
  	for (bits = max_bits; *p == 0x00 && bits > 0; p++)
  		bits -= 8;
  	for (i = *p; (i & j) != j; j >>= 1)
  		bits--;
  	return (bits);
  }
  
  /*%
   * calculates a checksum used in dst for an id.
   * takes an array of bytes and a length.
   * returns a 16  bit checksum.
   */
  u_int16_t
  dst_s_id_calc(const u_char *key, const int keysize)
  {
  	u_int32_t ac;
  	const u_char *kp = key;
  	int size = keysize;
  
  	if (!key || (keysize <= 0))
  		return (0xffffU);
   
  	for (ac = 0; size > 1; size -= 2, kp += 2)
  		ac += ((*kp) << 8) + *(kp + 1);
  
  	if (size > 0)
  		ac += ((*kp) << 8);
  	ac += (ac >> 16) & 0xffff;
  
  	return (ac & 0xffff);
  }
  
  /*%
   * dst_s_dns_key_id() Function to calculate DNSSEC footprint from KEY record
   *   rdata
   * Input:
   *	dns_key_rdata: the raw data in wire format 
   *      rdata_len: the size of the input data 
   * Output:
   *      the key footprint/id calculated from the key data 
   */ 
  u_int16_t
  dst_s_dns_key_id(const u_char *dns_key_rdata, const int rdata_len)
  {
  	if (!dns_key_rdata)
  		return 0;
  
  	/* compute id */
  	if (dns_key_rdata[3] == KEY_RSA)	/*%< Algorithm RSA */
  		return dst_s_get_int16((const u_char *)
  				       &dns_key_rdata[rdata_len - 3]);
  	else if (dns_key_rdata[3] == KEY_HMAC_MD5)
  		/* compatibility */
  		return 0;
  	else
  		/* compute a checksum on the key part of the key rr */
  		return dst_s_id_calc(dns_key_rdata, rdata_len);
  }
  
  /*%
   * dst_s_get_int16
   *     This routine extracts a 16 bit integer from a two byte character
   *     string.  The character string is assumed to be in network byte
   *     order and may be unaligned.  The number returned is in host order.
   * Parameter
   *     buf     A two byte character string.
   * Return
   *     The converted integer value.
   */
  
  u_int16_t
  dst_s_get_int16(const u_char *buf)
  {
  	register u_int16_t a = 0;
  	a = ((u_int16_t)(buf[0] << 8)) | ((u_int16_t)(buf[1]));
  	return (a);
  }
  
  /*%
   * dst_s_get_int32  *     This routine extracts a 32 bit integer from a four byte character
   *     string.  The character string is assumed to be in network byte
   *     order and may be unaligned.  The number returned is in host order.
   * Parameter
   *     buf     A four byte character string.
   * Return
   *     The converted integer value.
   */
  
  u_int32_t
  dst_s_get_int32(const u_char *buf)
  {
  	register u_int32_t a = 0;
  	a = ((u_int32_t)(buf[0] << 24)) | ((u_int32_t)(buf[1] << 16)) |
  		((u_int32_t)(buf[2] << 8)) | ((u_int32_t)(buf[3]));
  	return (a);
  }
  
  /*%
   * dst_s_put_int16
   *     Take a 16 bit integer and store the value in a two byte
   *     character string.  The integer is assumed to be in network
   *     order and the string is returned in host order.
   *
   * Parameters
   *     buf     Storage for a two byte character string.
   *     val     16 bit integer.
   */
  
  void
  dst_s_put_int16(u_int8_t *buf, const u_int16_t val)
  {
  	buf[0] = (u_int8_t)(val >> 8);
  	buf[1] = (u_int8_t)(val);
  }
  
  /*%
   * dst_s_put_int32  *     Take a 32 bit integer and store the value in a four byte
   *     character string.  The integer is assumed to be in network
   *     order and the string is returned in host order.
   *
   * Parameters
   *     buf     Storage for a four byte character string.
   *     val     32 bit integer.
   */
  
  void
  dst_s_put_int32(u_int8_t *buf, const u_int32_t val)
  {
  	buf[0] = (u_int8_t)(val >> 24);
  	buf[1] = (u_int8_t)(val >> 16);
  	buf[2] = (u_int8_t)(val >> 8);
  	buf[3] = (u_int8_t)(val);
  }
  
  /*%
   *  dst_s_filename_length
   *
   *	This function returns the number of bytes needed to hold the
   *	filename for a key file.  '/', '\' and ':' are not allowed.
   *	form:  K&lt;keyname&gt;+&lt;alg&gt;+&lt;id&gt;.&lt;suffix&gt;
   *
   *	Returns 0 if the filename would contain either '\', '/' or ':'
   */
  size_t
  dst_s_filename_length(const char *name, const char *suffix)
  {
  	if (name == NULL)
  		return (0);
  	if (strrchr(name, '\\'))
  		return (0);
  	if (strrchr(name, '/'))
  		return (0);
  	if (strrchr(name, ':'))
  		return (0);
  	if (suffix == NULL)
  		return (0);
  	if (strrchr(suffix, '\\'))
  		return (0);
  	if (strrchr(suffix, '/'))
  		return (0);
  	if (strrchr(suffix, ':'))
  		return (0);
  	return (1 + strlen(name) + 6 + strlen(suffix));
  }
  
  /*%
   *  dst_s_build_filename ()
   *	Builds a key filename from the key name, it's id, and a
   *	suffix.  '\', '/' and ':' are not allowed. fA filename is of the
   *	form:  K&lt;keyname&gt;&lt;id&gt;.&lt;suffix&gt;
   *	form: K&lt;keyname&gt;+&lt;alg&gt;+&lt;id&gt;.&lt;suffix&gt;
   *
   *	Returns -1 if the conversion fails:
   *	  if the filename would be too long for space allotted
   *	  if the filename would contain a '\', '/' or ':'
   *	Returns 0 on success
   */
  
  int
  dst_s_build_filename(char *filename, const char *name, u_int16_t id,
  		     int alg, const char *suffix, size_t filename_length)
  {
  	u_int32_t my_id;
  	if (filename == NULL)
  		return (-1);
  	memset(filename, 0, filename_length);
  	if (name == NULL)
  		return (-1);
  	if (suffix == NULL)
  		return (-1);
  	if (filename_length < 1 + strlen(name) + 4 + 6 + 1 + strlen(suffix))
  		return (-1);
  	my_id = id;
  	sprintf(filename, "K%s+%03d+%05d.%s", name, alg, my_id,
  		(const char *) suffix);
  	if (strrchr(filename, '/'))
  		return (-1);
  	if (strrchr(filename, '\\'))
  		return (-1);
  	if (strrchr(filename, ':'))
  		return (-1);
  	return (0);
  }
  
  /*%
   *  dst_s_fopen ()
   *     Open a file in the dst_path directory.  If perm is specified, the
   *     file is checked for existence first, and not opened if it exists.
   *  Parameters
   *     filename  File to open
   *     mode       Mode to open the file (passed directly to fopen)
   *     perm       File permission, if creating a new file.
   *  Returns
   *     NULL       Failure
   *     NON-NULL  (FILE *) of opened file.
   */
  FILE *
  dst_s_fopen(const char *filename, const char *mode, int perm)
  {
  	FILE *fp;
  	char pathname[PATH_MAX];
  
  	if (strlen(filename) + strlen(dst_path) >= sizeof(pathname))
  		return (NULL);
  
  	if (*dst_path != '\0') {
  		strcpy(pathname, dst_path);
  		strcat(pathname, filename);
  	} else
  		strcpy(pathname, filename);
  	
  	fp = fopen(pathname, mode);
  	if (perm)
  		chmod(pathname, perm);
  	return (fp);
  }
  
  void
  dst_s_dump(const int mode, const u_char *data, const int size, 
  	    const char *msg)
  {
  	UNUSED(data);
  
  	if (size > 0) {
  #ifdef LONG_TEST
  		static u_char scratch[1000];
  		int n ;
  		n = b64_ntop(data, scratch, size, sizeof(scratch));
  		printf("%s: %x %d %s\n", msg, mode, n, scratch);
  #else
  		printf("%s,%x %d\n", msg, mode, size);
  #endif
  	}
  }
  
  /*! \file */
  