inet_ntop.c

Windump3.6.2源代码

/*
 * Copyright (c) 1999 Kungliga Tekniska H鰃skolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * 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 Kungliga Tekniska
 *      H鰃skolan and its contributors.
 * 
 * 4. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
 */

/* $Id: inet_ntop.c,v 1.3 2000/01/09 21:35:45 fenner Exp $ */

#ifndef lint
static const char rcsid[] =
     "@(#) $Header: /tcpdump/master/tcpdump/missing/inet_ntop.c,v 1.3 2000/01/09 21:35:45 fenner Exp $";
#endif

#include <stdio.h>
#include <errno.h>
#ifndef WIN32
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#else
#ifdef __MINGW32__
int* _errno();
#define errno (*_errno())
#endif /* __MINGW32__ */
#include <winsock2.h>
#endif /* WIN32 */

/*
 *
 */

#ifndef INET_ADDRSTRLEN
#define INET_ADDRSTRLEN    16
#endif

static const char *
inet_ntop_v4 (const void *src, char *dst, size_t size)
{
    const char digits[] = "0123456789";
    int i;
    struct in_addr *addr = (struct in_addr *)src;
    u_long a = ntohl(addr->s_addr);
    const char *orig_dst = dst;

    if (size < INET_ADDRSTRLEN) {
	errno = ENOSPC;
	return NULL;
    }
    for (i = 0; i < 4; ++i) {
	int n = (a >> (24 - i * 8)) & 0xFF;
	int non_zerop = 0;

	if (non_zerop || n / 100 > 0) {
	    *dst++ = digits[n / 100];
	    n %= 100;
	    non_zerop = 1;
	}
	if (non_zerop || n / 10 > 0) {
	    *dst++ = digits[n / 10];
	    n %= 10;
	    non_zerop = 1;
	}
	*dst++ = digits[n];
	if (i != 3)
	    *dst++ = '.';
    }
    *dst++ = '\0';
    return orig_dst;
}

#ifdef WIN32

static const char *
inet_ntop_v6(const void *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++)
		words[i / 2] |= (((u_char*)src)[i] << ((1 - (i % 2)) << 3));
	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_ntop_v4(((u_char*)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) {
		errno = ENOSPC;
		return (NULL);
	}
	strcpy(dst, tmp);
	return (dst);
}

#endif


const char *
inet_ntop(int af, const void *src, char *dst, size_t size)
{
    switch (af) {
    case AF_INET :
	return inet_ntop_v4 (src, dst, size);
#ifdef WIN32
	case AF_INET6 :
	return inet_ntop_v6 (src, dst, size);
#endif
    default :
	errno = EAFNOSUPPORT;
	return NULL;
    }
}