inet_pton.h

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/*
 * Copyright (C) 2004, 2005, 2007, 2011-2014  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1996-2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */
 
/*
 * 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);
static int inet_pton6(const char *src, unsigned char *dst);
 
static int os_inet_pton(int af, const char *src, void *dst)
{
    switch (af) {
    case AF_INET:
        return (inet_pton4(src, dst));
    case AF_INET6:
        return (inet_pton6(src, dst));
    default:
        /* errno = EAFNOSUPPORT */;
        return (-1);
    }
    /* NOTREACHED */
}
 
static int inet_pton4(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;
 
            new += (unsigned int)(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);
            /*
             * "clang --analyse" generates warnings using:
             *      *++tp = 0;
             */
            tp++;
            *tp = 0;
            saw_digit = 0;
        } else
            return (0);
    }
    if (octets < 4)
        return (0);
    memmove(dst, tmp, NS_INADDRSZ);
    return (1);
}
 
static int inet_pton6(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, seen_xdigits;
    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;
    seen_xdigits = 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 (++seen_xdigits > 4)
                return (0);
            continue;
        }
        if (ch == ':') {
            curtok = src;
            if (!seen_xdigits) {
                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;
            seen_xdigits = 0;
            val = 0;
            continue;
        }
        if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
            inet_pton4(curtok, tp) > 0) {
            tp += NS_INADDRSZ;
            seen_xdigits = 0;
            break;  /* '\0' was seen by inet_pton4(). */
        }
        return (0);
    }
    if (seen_xdigits) {
        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 = (int)(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);
    memmove(dst, tmp, NS_IN6ADDRSZ);
    return (1);
}