/* inet_misc.c - inet_pton and inet_ntop for those who don't have it.
 * $Id: inet_misc.c 33 2005-10-02 20:50:00Z knight $
 *
 * Copyright (c) 1983, 1990, 1993
 *		The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *	  notice, this list of conditions and the following disclaimer in the
 *	  documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *	  must display the following acknowledgement:
 *		This product includes software developed by the University of
 *		California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *	  may be used to endorse or promote products derived from this software
 *	  without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.	IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.  */

/*	This inet_aton() function was taken from the GNU C library and
 *	incorporated into ircd-hybrid for those systems which do not have this
 *	routine in their standard C libraries.
 *
 *	The function was been extracted whole from the file inet_aton.c in
 *	Release 5.3.12 of the Linux C library, which is derived from the
 *	GNU C library, by Bryan Henderson in October 1996.	The copyright
 *	notice from that file is below.
 */

#include "stdinc.h"
#include "irc_res.h"

#ifdef NO_IN6ADDR_ANY
/* Stolen from glibc */
const struct in6_addr in6addr_any =
{ { { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } } };
#endif

#ifdef NO_INET_ATON
/*
 * Check whether "cp" is a valid ascii representation
 * of an Internet address and convert to a binary address.
 * Returns 1 if the address is valid, 0 if not.
 * This replaces inet_addr, the return value from which
 * cannot distinguish between failure and a local broadcast address.
 */
int
inet_aton(const char *cp, struct in_addr * addr)
{
	unsigned int val;
	int			 base,
				 n;
	char		 c;
	unsigned int parts[4];
	unsigned int *pp = parts;

	for (;;)
	{
		/*
		 * Collect number up to ``.''. Values are specified as for C:
		 * 0x=hex, 0=octal, other=decimal.
		 */
		val = 0;
		base = 10;
		if (*cp == '0')
		{
			if (*++cp == 'x' || *cp == 'X')
				base = 16, cp++;
			else
				base = 8;
		}
		while ((c = *cp) != '\0')
		{
			if (isdigit((unsigned char) c))
			{
				val = (val * base) + (c - '0');
				cp++;
				continue;
			}
			if (base == 16 && isxdigit((unsigned char) c))
			{
				val = (val << 4) +
					(c + 10 - (islower((unsigned char) c) ? 'a' : 'A'));
				cp++;
				continue;
			}
			break;
		}
		if (*cp == '.')
		{
			/*
			 * Internet format: a.b.c.d a.b.c	(with c treated as
			 * 16-bits) a.b		(with b treated as 24 bits)
			 */
			if (pp >= parts + 3 || val > 0xff)
				return 0;
			*pp++ = val, cp++;
		}
		else
			break;
	}

	/*
	 * Check for trailing junk.
	 */
	while (*cp)
		if (!isspace((unsigned char) *cp++))
			return 0;

	/*
	 * Concoct the address according to the number of parts specified.
	 */
	n = pp - parts + 1;
	switch (n)
	{

		case 1:			/* a -- 32 bits */
			break;

		case 2:			/* a.b -- 8.24 bits */
			if (val > 0xffffff)
				return 0;
			val |= parts[0] << 24;
			break;

		case 3:			/* a.b.c -- 8.8.16 bits */
			if (val > 0xffff)
				return 0;
			val |= (parts[0] << 24) | (parts[1] << 16);
			break;

		case 4:			/* a.b.c.d -- 8.8.8.8 bits */
			if (val > 0xff)
				return 0;
			val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
			break;
	}
	if (addr)
		addr->s_addr = htonl(val);
	return 1;
}

#endif /* NO_INET_ATON */

#ifdef NO_INET_NTOP
static const char *inet_ntop4(const unsigned char *src, char *dst,
			      size_t size);

#ifdef IPV6
static const char *inet_ntop6(const unsigned char *src, char *dst,
			      size_t size);
#endif

/* char *
 * isc_net_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.
 */
const char *
inet_ntop(int af, const void *src, char *dst, size_t size)
{
	switch (af) {
	case AF_INET:
		return (inet_ntop4(src, dst, size));
#ifdef IPV6
	case AF_INET6:
		return (inet_ntop6(src, dst, size));
#endif
	default:
		errno = EAFNOSUPPORT;
		return (NULL);
	}
	/* NOTREACHED */
}

/* const char *
 * inet_ntop4(src, dst, size)
 *	format an IPv4 address
 * return:
 *	`dst' (as a const)
 * notes:
 *	(1) uses no statics
 *	(2) takes a unsigned char* not an in_addr as input
 * author:
 *	Paul Vixie, 1996.
 */
static const char *
inet_ntop4(const unsigned char *src, char *dst, size_t size)
{
	static const char *fmt = "%u.%u.%u.%u";
	char tmp[sizeof "255.255.255.255"];

	if ((size_t)sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) >= size)
	{
		errno = ENOSPC;
		return (NULL);
	}
	strcpy(dst, tmp);

	return (dst);
}

/* const char *
 * isc_inet_ntop6(src, dst, size)
 *	convert IPv6 binary address into presentation (printable) format
 * author:
 *	Paul Vixie, 1996.
 */
#ifdef IPV6
static const char *
inet_ntop6(const unsigned 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;
	unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
	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 < NS_IN6ADDRSZ; i++)
		words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
	best.base = -1;
	cur.base = -1;
	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); 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 < (NS_IN6ADDRSZ / NS_INT16SZ); 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) ==
	    (NS_IN6ADDRSZ / NS_INT16SZ))
		*tp++ = ':';
	*tp++ = '\0';

	/*
	 * Check for overflow, copy, and we're done.
	 */
	if ((size_t)(tp - tmp) > size) {
		errno = ENOSPC;
		return (NULL);
	}
	strcpy(dst, tmp);
	return (dst);
}
#endif /* IPV6 */

#endif /* NO_INET_NTOP */

#ifdef NO_INET_PTON

static int inet_pton4(const char *src, unsigned char *dst);
#ifdef IPV6
static int inet_pton6(const char *src, unsigned char *dst);
#endif

/* 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.
 */
int
inet_pton(int af,
	  const char *src,
	  void *dst)
{
	switch (af) {
	case AF_INET:
		return (inet_pton4(src, dst));
#ifdef IPV6
	case AF_INET6:
		return (inet_pton6(src, dst));
#endif
	default:
		errno = EAFNOSUPPORT;
		return (-1);
	}
	/* NOTREACHED */
}

/* 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(src, dst)
	const char *src;
	unsigned char *dst;
{
	static const char digits[] = "0123456789";
	int saw_digit, octets, ch;
	unsigned char tmp[NS_INADDRSZ], *tp;

	saw_digit = 0;
	octets = 0;
	*(tp = tmp) = 0;
	while ((ch = *src++) != '\0') {
		const char *pch;

		if ((pch = strchr(digits, ch)) != NULL) {
			unsigned int new = *tp * 10 + (pch - digits);

			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);
}

/* 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 IPV6
static int
inet_pton6(src, dst)
	const char *src;
	unsigned char *dst;
{
	static const char xdigits_l[] = "0123456789abcdef",
			  xdigits_u[] = "0123456789ABCDEF";
	unsigned char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
	const char *xdigits, *curtok;
	int ch, saw_xdigit;
	unsigned int val;

	memset((tp = 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 = *src++) != '\0') {
		const char *pch;

		if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
			pch = strchr((xdigits = xdigits_u), 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;
			}
			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;

		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);
}
#endif /* IPV6 */

#endif /* NO_INET_PTON */
