src/utils/inet_pton.cpp

/*
 * Copyright (c) 1996-1999 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.
 */

#include "autoconfig.h"

#ifndef HAVE_INET_PTON
#include <stdio.h>

#include "UpnpInet.h"
#include "inet_pton.h"
/* For upnp_strlcpy */
#include "genut.h"

/*%
 * 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 char    *inet_ntop4(const unsigned char *src, char *dst, socklen_t size);
static char    *inet_ntop6(const unsigned char *src, char *dst, socklen_t size);

/* const char *inet_ntop(af, src, dst, size)
 *    convert a network format address to presentation format.
 * return:
 *    pointer to presentation format address (`dst'), or NULL (see errno).
 * author:
 *    Paul Vixie, 1996.
 */
const char *inet_ntop(int af, const void *src, char *dst, socklen_t size)
{
    switch (af) {
    case AF_INET:
        return (inet_ntop4((const unsigned char*)src, dst, size));
    case AF_INET6:
        return (inet_ntop6((const unsigned char*)src, dst, size));
    default:
        return (NULL);
    }
    /* NOTREACHED */
}

/* const char *inet_ntop4(src, dst, size)
 *    format an IPv4 address
 * return:
 *    `dst' (as a const)
 * notes:
 *    (1) uses no statics
 *    (2) takes a u_char* not an in_addr as input
 * author:
 *    Paul Vixie, 1996.
 */
static char *inet_ntop4(const unsigned char *src, char *dst, socklen_t size)
{
    static const char fmt[] = "%u.%u.%u.%u";
    char tmp[sizeof "255.255.255.255"];
    int l;

    l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
    if (l <= 0 || (socklen_t) l >= size) {
        return (NULL);
    }
    upnp_strlcpy(dst, tmp, size);
    return (dst);
}

/* const char *inet_ntop6(src, dst, size)
 *    convert IPv6 binary address into presentation (printable) format
 * author:
 *    Paul Vixie, 1996.
 */
static char *inet_ntop6(const unsigned char *src, char *dst, socklen_t size)
{
    /*
     * Note that int32_t and int16_t need only be "at least" large enough
     * to contain a value of the specified size.  On some systems, like
     * Crays, there is no such thing as an integer variable with 16 bits.
     * Keep this in mind if you think this function should have been coded
     * to use pointer overlays.  All the world's not a VAX.
     */
    char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
    struct { int base, len; } best, cur;
#define NS_IN6ADDRSZ    16
#define NS_INT16SZ    2
    u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
    int i;

    /*
     * Preprocess:
     *    Copy the input (bytewise) array into a wordwise array.
     *    Find the longest run of 0x00's in src[] for :: shorthanding.
     */

    memset(words, '\0', sizeof words);
    for (i = 0; i < NS_IN6ADDRSZ; i++)
        words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
    best.base = -1;
    best.len = 0;
    cur.base = -1;
    cur.len = 0;
    for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
        if (words[i] == 0) {
            if (cur.base == -1)
                cur.base = i, cur.len = 1;
            else
                cur.len++;
        } else {
            if (cur.base != -1) {
                if (best.base == -1 || cur.len > best.len)
                    best = cur;
                cur.base = -1;
            }
        }
    }
    if (cur.base != -1) {
        if (best.base == -1 || cur.len > best.len)
            best = cur;
    }
    if (best.base != -1 && best.len < 2)
        best.base = -1;

    /*
     * Format the result.
     */
    tp = tmp;
    for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
        /* Are we inside the best run of 0x00's? */
        if (best.base != -1 && i >= best.base &&
            i < (best.base + best.len)) {
            if (i == best.base)
                *tp++ = ':';
            continue;
        }
        /* Are we following an initial run of 0x00s or any real hex? */
        if (i != 0)
            *tp++ = ':';
        /* Is this address an encapsulated IPv4? */
        if (i == 6 && best.base == 0 && (best.len == 6 ||
            (best.len == 7 && words[7] != 0x0001) ||
            (best.len == 5 && words[5] == 0xffff))) {
            if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
                return (NULL);
            tp += strlen(tp);
            break;
        }
        tp += sprintf(tp, "%x", words[i]);
    }
    /* Was it a trailing run of 0x00's? */
    if (best.base != -1 && (best.base + best.len) ==
        (NS_IN6ADDRSZ / NS_INT16SZ))
        *tp++ = ':';
    *tp++ = '\0';

    /*
     * Check for overflow, copy, and we're done.
     */
    if ((socklen_t)(tp - tmp) > size) {
        return (NULL);
    }
    strcpy(dst, tmp);
    return (dst);
}


/*
 * 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, u_char *dst);
static int    inet_pton6(const char *src, u_char *dst);

/* 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));
    case AF_INET6:
        return (inet_pton6(src, (unsigned char *)dst));
    default:
        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, u_char *dst)
{
    static const char digits[] = "0123456789";
    int saw_digit, octets, ch;
#define NS_INADDRSZ    4
    u_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) {
            u_int uiNew = *tp * 10 + (pch - digits);

            if (saw_digit && *tp == 0)
                return (0);
            if (uiNew > 255)
                return (0);
            *tp = uiNew;
            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, NS_INADDRSZ);
    return (1);
}

/* 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, u_char *dst)
{
    static const char xdigits_l[] = "0123456789abcdef",
              xdigits_u[] = "0123456789ABCDEF";
#define NS_IN6ADDRSZ    16
#define NS_INT16SZ    2
    u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
    const char *xdigits, *curtok;
    int ch, seen_xdigits;
    u_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;
            } else if (*src == '\0') {
                return (0);
            }
            if (tp + NS_INT16SZ > endp)
                return (0);
            *tp++ = (u_char) (val >> 8) & 0xff;
            *tp++ = (u_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++ = (u_char) (val >> 8) & 0xff;
        *tp++ = (u_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;

        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);
    memcpy(dst, tmp, NS_IN6ADDRSZ);
    return (1);
}
#endif /* !HAVE_INET_PTON */