/* 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.
 */

/* Modified by Fyodor (fyodor@nmap.org) for inclusion in the Nmap
 * Security Scanner.
 *
 * $Id$
 */

#include "nbase.h"

#ifndef HAVE_INET_PTON

#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif

#ifndef IN6ADDRSZ
#define IN6ADDRSZ   16
#endif

#ifndef INT16SZ
#define INT16SZ 2
#endif

#ifndef INADDRSZ
#define INADDRSZ    4
#endif

#if !defined(EAFNOSUPPORT) && defined(WSAEAFNOSUPPORT)
#define EAFNOSUPPORT WSAEAFNOSUPPORT
#endif

/*
 * 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.
 */

static int    inet_pton4 (const char *src, unsigned char *dst);
#if HAVE_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, (unsigned char *) dst));
#if HAVE_IPV6
    case AF_INET6:
        return (inet_pton6(src, (unsigned char *) dst));
#endif
    default:
#ifndef WIN32
        errno = EAFNOSUPPORT;
#endif
        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(const char *src, unsigned char *dst)
{
    static const char digits[] = "0123456789";
    int saw_digit, octets, ch;
    unsigned char tmp[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 newval = (unsigned int) (*tp * 10 + (pch - digits));

            if (newval > 255)
                return (0);
            *tp = newval;
            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, INADDRSZ);
    return (1);
}

#if HAVE_IPV6
/* 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.
 */
static int
inet_pton6(const char *src, unsigned char *dst)
{
    static const char xdigits_l[] = "0123456789abcdef",
              xdigits_u[] = "0123456789ABCDEF";
    unsigned char tmp[IN6ADDRSZ], *tp, *endp, *colonp;
    const char *xdigits, *curtok;
    int ch, saw_xdigit;
    unsigned int val;

    memset((tp = tmp), '\0', IN6ADDRSZ);
    endp = tp + 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 + INT16SZ > endp)
                return (0);
            *tp++ = (unsigned char) (val >> 8) & 0xff;
            *tp++ = (unsigned char) val & 0xff;
            saw_xdigit = 0;
            val = 0;
            continue;
        }
        if (ch == '.' && ((tp + INADDRSZ) <= endp) &&
            inet_pton4(curtok, tp) > 0) {
            tp += INADDRSZ;
            saw_xdigit = 0;
            break;    /* '\0' was seen by inet_pton4(). */
        }
        return (0);
    }
    if (saw_xdigit) {
        if (tp + 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, IN6ADDRSZ);
    return (1);
}
#endif

#endif /* ifndef HAVE_INET_PTON */
