text: /*
   * 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.
   */
  
  #define __FORCE_GLIBC
  #include <features.h>
  #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 <errno.h>
  #include <stdio.h>
  #include <string.h>
  #include <ctype.h>
  
  
  /*
   * WARNING: Don't even consider trying to compile this on a system where
   * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
   */
  
  
  /* const char *
   * inet_ntop4(src, dst, size)
   *	format an IPv4 address
   * return:
   *	`dst' (as a const)
   * notes:
   *	(1) uses no statics
   *	(2) takes a u_char* not an in_addr as input
   * author:
   *	Paul Vixie, 1996.
   */
  static const char *
  inet_ntop4(const u_char *src, char *dst, size_t size)
  {
  	char tmp[sizeof ("255.255.255.255") + 1] = "\0";
  	int octet;
  	int i;
  
  	i = 0;
  	for (octet = 0; octet <= 3; octet++) {
  
  #if 0	/* since src is unsigned char, it will never be > 255 ... */
  		if (src[octet] > 255) {
  			__set_errno (ENOSPC);
  			return (NULL);
  		}
  #endif
  		tmp[i++] = '0' + src[octet] / 100;
  		if (tmp[i - 1] == '0') {
  			tmp[i - 1] = '0' + (src[octet] / 10 % 10);
  			if (tmp[i - 1] == '0') i--;
  		} else {
  			tmp[i++] = '0' + (src[octet] / 10 % 10);
  		}
  		tmp[i++] = '0' + src[octet] % 10;
  		tmp[i++] = '.';
  	}
  	tmp[i - 1] = '\0';
  
  	if (strlen (tmp) > size) {
  		__set_errno (ENOSPC);
  		return (NULL);
  	}
  
  	return strcpy(dst, tmp);
  }
  
  
  /* const char *
   * inet_ntop6(src, dst, size)
   *	convert IPv6 binary address into presentation (printable) format
   * author:
   *	Paul Vixie, 1996.
   */
  
  #ifdef __UCLIBC_HAS_IPV6__
  
  static const char *
  inet_ntop6(const u_char *src, char *dst, size_t size)
  {
  	/*
  	 * Note that int32_t and int16_t need only be "at least" large enough
  	 * to contain a value of the specified size.  On some systems, like
  	 * Crays, there is no such thing as an integer variable with 16 bits.
  	 * Keep this in mind if you think this function should have been coded
  	 * to use pointer overlays.  All the world's not a VAX.
  	 */
  	char tmp[sizeof ("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
  	struct { int base, len; } best, cur;
  	u_int words[8];
  	int i;
  
  	/*
  	 * Preprocess:
  	 *	Copy the input (bytewise) array into a wordwise array.
  	 *	Find the longest run of 0x00's in src[] for :: shorthanding.
  	 */
  	memset(words, '\0', sizeof words);
  	for (i = 0; i < 16; i += 2)
  		words[i / 2] = (src[i] << 8) | src[i + 1];
  	best.base = -1;
  	cur.base = -1;
  	for (i = 0; i < 8; i++) {
  		if (words[i] == 0) {
  			if (cur.base == -1)
  				cur.base = i, cur.len = 1;
  			else
  				cur.len++;
  		} else {
  			if (cur.base != -1) {
  				if (best.base == -1 || cur.len > best.len)
  					best = cur;
  				cur.base = -1;
  			}
  		}
  	}
  	if (cur.base != -1) {
  		if (best.base == -1 || cur.len > best.len)
  			best = cur;
  	}
  	if (best.base != -1 && best.len < 2)
  		best.base = -1;
  
  	/*
  	 * Format the result.
  	 */
  	tp = tmp;
  	for (i = 0; i < 8; i++) {
  		/* Are we inside the best run of 0x00's? */
  		if (best.base != -1 && i >= best.base &&
  		    i < (best.base + best.len)) {
  			if (i == best.base)
  				*tp++ = ':';
  			continue;
  		}
  		/* Are we following an initial run of 0x00s or any real hex? */
  		if (i != 0)
  			*tp++ = ':';
  		/* Is this address an encapsulated IPv4? */
  		if (i == 6 && best.base == 0 &&
  		    (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
  			if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
  				return (NULL);
  			tp += strlen(tp);
  			break;
  		}
  		tp += sprintf(tp, "%x", words[i]);
  	}
  	/* Was it a trailing run of 0x00's? */
  	if (best.base != -1 && (best.base + best.len) == 8)
  		*tp++ = ':';
  	*tp++ = '\0';
  
  	/*
  	 * Check for overflow, copy, and we're done.
  	 */
  	if ((size_t)(tp - tmp) > size) {
  		__set_errno (ENOSPC);
  		return (NULL);
  	}
  	return strcpy(dst, tmp);
  }
  #endif /* __UCLIBC_HAS_IPV6__ */
  
  
  /* int
   * inet_pton4(src, dst)
   *	like inet_aton() but without all the hexadecimal 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, u_char *dst)
  {
  	int saw_digit, octets, ch;
  	u_char tmp[4], *tp;
  
  	saw_digit = 0;
  	octets = 0;
  	*(tp = tmp) = 0;
  	while ((ch = *src++) != '\0') {
  
  		if (ch >= '0' && ch <= '9') {
  			u_int new = *tp * 10 + (ch - '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, 4);
  	return (1);
  }
  
  /* int
   * inet_pton6(src, dst)
   *	convert 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.
   */
  
  #ifdef __UCLIBC_HAS_IPV6__
  
  /* We cannot use the macro version of tolower() or very bad
   * things happen when '*src++' gets evaluated multiple times.  
   * So * undef it here so we get the function version of tolower
   * instead.
   */
  #undef tolower
  
  static int
  inet_pton6(const char *src, u_char *dst)
  {
  	static const char xdigits[] = "0123456789abcdef";
  	u_char tmp[16], *tp, *endp, *colonp;
  	const char *curtok;
  	int ch, saw_xdigit;
  	u_int val;
  
  
  	tp = memset(tmp, '\0', 16);
  	endp = tp + 16;
  	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 + 2 > endp)
  				return (0);
  			*tp++ = (u_char) (val >> 8) & 0xff;
  			*tp++ = (u_char) val & 0xff;
  			saw_xdigit = 0;
  			val = 0;
  			continue;
  		}
  		if (ch == '.' && ((tp + 4) <= endp) &&
  		    inet_pton4(curtok, tp) > 0) {
  			tp += 4;
  			saw_xdigit = 0;
  			break;	/* '\0' was seen by inet_pton4(). */
  		}
  		return (0);
  	}
  	if (saw_xdigit) {
  		if (tp + 2 > endp)
  			return (0);
  		*tp++ = (u_char) (val >> 8) & 0xff;
  		*tp++ = (u_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, 16);
  	return (1);
  }
  
  #endif /* __UCLIBC_HAS_IPV6__ */
  
  
  
  /* char *
   * inet_ntop(af, src, dst, size)
   *	convert a network format address to presentation format.
   * return:
   *	pointer to presentation format address (`dst'), or NULL (see errno).
   * author:
   *	Paul Vixie, 1996.
   */
  extern const char *
  inet_ntop(af, src, dst, size)
  	int af;
  	const void *src;
  	char *dst;
  	socklen_t size;
  {
  	switch (af) {
  	case AF_INET:
  		return (inet_ntop4(src, dst, size));
  #ifdef __UCLIBC_HAS_IPV6__
  	case AF_INET6:
  		return (inet_ntop6(src, dst, size));
  #endif
  	default:
  		__set_errno (EAFNOSUPPORT);
  		return (NULL);
  	}
  	/* NOTREACHED */
  }
  
  
  /* int
   * inet_pton(af, src, 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.
   */
  extern int
  inet_pton(af, src, dst)
  	int af;
  	const char *src;
  	void *dst;
  {
  	switch (af) {
  	case AF_INET:
  		return (inet_pton4(src, dst));
  #ifdef __UCLIBC_HAS_IPV6__
  	case AF_INET6:
  		return (inet_pton6(src, dst));
  #endif
  	default:
  		__set_errno (EAFNOSUPPORT);
  		return (-1);
  	}
  	/* NOTREACHED */
  }
  
  