inet_pton.c

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/*
 * Copyright (C) 2004, 2005, 2007, 2013, 2014  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1996-2003  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.
 */

/*! \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 new = *tp * 10;

                        new += (int)(pch - digits);
                        if (saw_digit && *tp == 0)
                                return (0);
                        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);
                        *++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);
}

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