/*
 * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
 * 
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */

/*
 * Copyright 1994, 1995 Massachusetts Institute of Technology
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that both the above copyright notice and this
 * permission notice appear in all copies, that both the above
 * copyright notice and this permission notice appear in all
 * supporting documentation, and that the name of M.I.T. not be used
 * in advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.  M.I.T. makes
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied
 * warranty.
 *
 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
 * SHALL M.I.T. 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.
 */

#include <sys/param.h>
#include <sys/systm.h>

#include <netinet/in.h>

static const char *hexchars = "0123456789abcdef";

static const char *
inet_ntop4(const struct in_addr *addr, char *buf, size_t len)
{
	const u_int8_t *ap = (const u_int8_t *)&addr->s_addr;
	char tmp[MAX_IPv4_STR_LEN]; /* max length of ipv4 addr string */
	int fulllen;
	
	/*
	 * snprintf returns number of bytes printed (not including NULL) or
	 * number of bytes that would have been printed if more than would
	 * fit
	 */
	fulllen = snprintf(tmp, sizeof(tmp), "%d.%d.%d.%d",
					   ap[0], ap[1], ap[2], ap[3]);
	if (fulllen >= (int)len) {
		return NULL;
	}
	
	bcopy(tmp, buf, fulllen + 1);
	
	return buf;
}

static const char *
inet_ntop6(const struct in6_addr *addr, char *dst, size_t size)
{
	char hexa[8][5], tmp[MAX_IPv6_STR_LEN];
	int zr[8];
	size_t len;
	int32_t i, j, k, skip;
	uint8_t x8, hx8;
	uint16_t x16;
	struct in_addr a4;
	
	if (addr == NULL) return NULL;
	
	bzero(tmp, sizeof(tmp));
	
	/*  check for mapped or compat addresses */
	i = IN6_IS_ADDR_V4MAPPED(addr);
	j = IN6_IS_ADDR_V4COMPAT(addr);
	if ((i != 0) || (j != 0))
	{
		char tmp2[16]; /* max length of ipv4 addr string */
		a4.s_addr = addr->__u6_addr.__u6_addr32[3];
		len = snprintf(tmp, sizeof(tmp), "::%s%s", (i != 0) ? "ffff:" : "",
					   inet_ntop4(&a4, tmp2, sizeof(tmp2)));
		if (len >= size) return NULL;
		bcopy(tmp, dst, len + 1);
		return dst;
	}
	
	k = 0;
	for (i = 0; i < 16; i += 2)
	{
		j = 0;
		skip = 1;
		
		bzero(hexa[k], 5);
		
		x8 = addr->__u6_addr.__u6_addr8[i];
		
		hx8 = x8 >> 4;
		if (hx8 != 0)
		{
			skip = 0;
			hexa[k][j++] = hexchars[hx8];
		}
		
		hx8 = x8 & 0x0f;
		if ((skip == 0) || ((skip == 1) && (hx8 != 0)))
		{
			skip = 0;
			hexa[k][j++] = hexchars[hx8];
		}
		
		x8 = addr->__u6_addr.__u6_addr8[i + 1];
		
		hx8 = x8 >> 4;
		if ((skip == 0) || ((skip == 1) && (hx8 != 0)))
		{
			hexa[k][j++] = hexchars[hx8];
		}
		
		hx8 = x8 & 0x0f;
		hexa[k][j++] = hexchars[hx8];
		
		k++;
	}
	
	/* find runs of zeros for :: convention */
	j = 0;
	for (i = 7; i >= 0; i--)
	{
		zr[i] = j;
		x16 = addr->__u6_addr.__u6_addr16[i];
		if (x16 == 0) j++;
		else j = 0;
		zr[i] = j;
	}
	
	/* find longest run of zeros */
	k = -1;
	j = 0;
	for(i = 0; i < 8; i++)
	{
		if (zr[i] > j)
		{
			k = i;
			j = zr[i];
		}
	}
	
	for(i = 0; i < 8; i++)
	{
		if (i != k) zr[i] = 0;
	}
	
	len = 0;
	for (i = 0; i < 8; i++)
	{
		if (zr[i] != 0)
		{
			/* check for leading zero */
			if (i == 0) tmp[len++] = ':';
			tmp[len++] = ':';
			i += (zr[i] - 1);
			continue;
		}
		for (j = 0; hexa[i][j] != '\0'; j++) tmp[len++] = hexa[i][j];
		if (i != 7) tmp[len++] = ':';
	}

	/* trailing NULL */
	len++;

	if (len > size) return NULL;
	bcopy(tmp, dst, len);
	return dst;
}

const char *
inet_ntop(int af, const void *addr, char *buf, size_t len)
{
	if(af==AF_INET6)
		return inet_ntop6(addr, buf, len);
	if(af==AF_INET)
		return inet_ntop4(addr, buf, len);
	return NULL;
}