lib/isc/inet_pton.c

/*
 * Copyright (C) 1996-2005, 2007, 2013, 2014, 2016, 2017  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/*! \file */

#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] =
    "$Id: inet_pton.c,v 1.19 2007/06/19 23:47:17 tbox Exp $";
#endif /* LIBC_SCCS and not lint */

#include <config.h>

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

#include <isc/net.h>

/*% INT16 Size */
#define NS_INT16SZ   2
/*% IPv4 Address Size */
#define NS_INADDRSZ  4
/*% IPv6 Address Size */
#define NS_IN6ADDRSZ    16

/*
 * 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);

/*%
 *  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
isc_net_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 */
}

/*!\fn static int inet_pton4(const char *src, unsigned char *dst)
 * \brief
 *  like inet_aton() but without all the hexadecimal and shorthand.
 * \return
 *  1 if `src' is a valid dotted quad, else 0.
 * \note
 *  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[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 byte = *tp * 10;

            byte += (int)(pch - digits);
            if (saw_digit && *tp == 0)
                return (0);
            if (byte > 255)
                return (0);
            *tp = byte;
            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);
    memmove(dst, tmp, NS_INADDRSZ);
    return (1);
}

/*%
 *  convert presentation level address to network order binary form.
 * \return
 *  1 if `src' is a valid [RFC1884 2.2] address, else 0.
 * \note
 *  (1) does not touch `dst' unless it's returning 1.
 * \note
 *  (2) :: in a full address is silently ignored.
 * \author
 *  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[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;

        if (tp == endp)
            return (0);
        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);
}