StdLib/BsdSocketLib/inet_net_ntop.c

/*
 * Copyright (c) 1996 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static const char orig_rcsid[] = "From Id: inet_net_ntop.c,v 8.2 1996/08/08 06:54:44 vixie Exp";
static const char rcsid[] = "$Id: inet_net_ntop.c,v 1.1.1.1 2003/11/19 01:51:29 kyu3 Exp $";
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#ifdef SPRINTF_CHAR
# define SPRINTF(x) strlen(sprintf/**/x)
#else
# define SPRINTF(x) ((size_t)sprintf x)
#endif

static char *   inet_net_ntop_ipv4 (const u_char *src, int bits,
                    char *dst, size_t size);

/*
 * char *
 * inet_net_ntop(af, src, bits, dst, size)
 *  convert network number from network to presentation format.
 *  generates CIDR style result always.
 * return:
 *  pointer to dst, or NULL if an error occurred (check errno).
 * author:
 *  Paul Vixie (ISC), July 1996
 */
char *
inet_net_ntop(
    int af,
    const void *src,
    int bits,
    char *dst,
    size_t size
    )
{
    switch (af) {
    case AF_INET:
        return (inet_net_ntop_ipv4(src, bits, dst, size));
    default:
        errno = EAFNOSUPPORT;
        return (NULL);
    }
}

/*
 * static char *
 * inet_net_ntop_ipv4(src, bits, dst, size)
 *  convert IPv4 network number from network to presentation format.
 *  generates CIDR style result always.
 * return:
 *  pointer to dst, or NULL if an error occurred (check errno).
 * note:
 *  network byte order assumed.  this means 192.5.5.240/28 has
 *  0x11110000 in its fourth octet.
 * author:
 *  Paul Vixie (ISC), July 1996
 */
static char *
inet_net_ntop_ipv4(
    const u_char *src,
    int bits,
    char *dst,
    size_t size
    )
{
    char *odst = dst;
    char *t;
    u_int m;
    int b;

    if (bits < 0 || bits > 32) {
        errno = EINVAL;
        return (NULL);
    }
    if (bits == 0) {
        if (size < sizeof "0")
            goto emsgsize;
        *dst++ = '0';
        *dst = '\0';
    }

    /* Format whole octets. */
    for (b = bits / 8; b > 0; b--) {
        if (size < sizeof "255.")
            goto emsgsize;
        t = dst;
        dst += SPRINTF((dst, "%u", *src++));
        if (b > 1) {
            *dst++ = '.';
            *dst = '\0';
        }
        size -= (size_t)(dst - t);
    }

    /* Format partial octet. */
    b = bits % 8;
    if (b > 0) {
        if (size < sizeof ".255")
            goto emsgsize;
        t = dst;
        if (dst != odst)
            *dst++ = '.';
        m = ((1 << b) - 1) << (8 - b);
        dst += SPRINTF((dst, "%u", *src & m));
        size -= (size_t)(dst - t);
    }

    /* Format CIDR /width. */
    if (size < sizeof "/32")
        goto emsgsize;
    dst += SPRINTF((dst, "/%u", bits));
    return (odst);

 emsgsize:
    errno = EMSGSIZE;
    return (NULL);
}