/*      $NetBSD: inet_cidr_pton.c,v 1.8 2012/03/20 17:08:13 matt Exp $  */

/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1998,1999 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 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.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static const char rcsid[] = "Id: inet_cidr_pton.c,v 1.6 2005/04/27 04:56:19 sra Exp";
#else
__RCSID("$NetBSD: inet_cidr_pton.c,v 1.8 2012/03/20 17:08:13 matt Exp $");
#endif
#endif

#include "port_before.h"

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>

#include <isc/assertions.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>

#include "port_after.h"

#ifdef SPRINTF_CHAR
# define SPRINTF(x) strlen(sprintf/**/x)
#else
# define SPRINTF(x) ((size_t)sprintf x)
#endif

#ifdef __weak_alias
__weak_alias(inet_cidr_pton,_inet_cidr_pton)
#endif

static int      inet_cidr_pton_ipv4(const char *src, u_char *dst,
                                         int *bits, int ipv6);
static int      inet_cidr_pton_ipv6(const char *src, u_char *dst, int *bits);

static int      getbits(const char *, int ipv6);

/*%
 * int
 * inet_cidr_pton(af, src, dst, *bits)
 *      convert network address from presentation to network format.
 *      accepts inet_pton()'s input for this "af" plus trailing "/CIDR".
 *      "dst" is assumed large enough for its "af".  "bits" is set to the
 *      /CIDR prefix length, which can have defaults (like /32 for IPv4).
 * return:
 *      -1 if an error occurred (inspect errno; ENOENT means bad format).
 *      0 if successful conversion occurred.
 * note:
 *      192.5.5.1/28 has a nonzero host part, which means it isn't a network
 *      as called for by inet_net_pton() but it can be a host address with
 *      an included netmask.
 * author:
 *      Paul Vixie (ISC), October 1998
 */
int
inet_cidr_pton(int af, const char *src, void *dst, int *bits) {
        switch (af) {
        case AF_INET:
                return (inet_cidr_pton_ipv4(src, dst, bits, 0));
        case AF_INET6:
                return (inet_cidr_pton_ipv6(src, dst, bits));
        default:
                errno = EAFNOSUPPORT;
                return (-1);
        }
}

static const char digits[] = "0123456789";

static int
inet_cidr_pton_ipv4(const char *src, u_char *dst, int *pbits, int ipv6) {
        const u_char *odst = dst;
        int ch, bits;
        ptrdiff_t n, tmp;
        size_t size = 4;

        /* Get the mantissa. */
        while (ch = *src++, (isascii(ch) && isdigit(ch))) {
                tmp = 0;
                do {
                        n = strchr(digits, ch) - digits;
                        INSIST(n >= 0 && n <= 9);
                        tmp *= 10;
                        tmp += n;
                        if (tmp > 255)
                                goto enoent;
                } while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
                if (size-- == 0U)
                        goto emsgsize;
                *dst++ = (u_char) tmp;
                if (ch == '\0' || ch == '/')
                        break;
                if (ch != '.')
                        goto enoent;
        }

        /* Get the prefix length if any. */
        bits = -1;
        if (ch == '/' && dst > odst) {
                bits = getbits(src, ipv6);
                if (bits == -2)
                        goto enoent;
        } else if (ch != '\0')
                goto enoent;

        /* Prefix length can default to /32 only if all four octets spec'd. */
        if (bits == -1) {
                if (dst - odst == 4)
                        bits = ipv6 ? 128 : 32;
                else
                        goto enoent;
        }

        /* If nothing was written to the destination, we found no address. */
        if (dst == odst)
                goto enoent;

        /* If prefix length overspecifies mantissa, life is bad. */
        if (((bits - (ipv6 ? 96 : 0)) / 8) > (dst - odst))
                goto enoent;

        /* Extend address to four octets. */
        while (size-- > 0U)
                *dst++ = 0;

        *pbits = bits;
        return (0);

 enoent:
        errno = ENOENT;
        return (-1);

 emsgsize:
        errno = EMSGSIZE;
        return (-1);
}

static int
inet_cidr_pton_ipv6(const char *src, u_char *dst, int *pbits) {
        static const char xdigits_l[] = "0123456789abcdef",
                          xdigits_u[] = "0123456789ABCDEF";
        u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
        const char *xdigits, *curtok;
        int ch, saw_xdigit;
        u_int val;
        int bits;

        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;
        saw_xdigit = 0;
        val = 0;
        bits = -1;
        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 |= (int)(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;
                        } else if (*src == '\0') {
                                return (0);
                        }
                        if (tp + NS_INT16SZ > endp)
                                return (0);
                        *tp++ = (u_char) (val >> 8) & 0xff;
                        *tp++ = (u_char) val & 0xff;
                        saw_xdigit = 0;
                        val = 0;
                        continue;
                }
                if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
                    inet_cidr_pton_ipv4(curtok, tp, &bits, 1) == 0) {
                        tp += NS_INADDRSZ;
                        saw_xdigit = 0;
                        break;  /*%< '\\0' was seen by inet_pton4(). */
                }
                if (ch == '/') {
                        bits = getbits(src, 1);
                        if (bits == -2)
                                goto enoent;
                        break;
                }
                goto enoent;
        }
        if (saw_xdigit) {
                if (tp + NS_INT16SZ > endp)
                        goto emsgsize;
                *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 ptrdiff_t n = tp - colonp;
                int i;

                if (tp == endp)
                        goto enoent;
                for (i = 1; i <= n; i++) {
                        endp[- i] = colonp[n - i];
                        colonp[n - i] = 0;
                }
                tp = endp;
        }

        memcpy(dst, tmp, NS_IN6ADDRSZ);

        *pbits = bits;
        return (0);

 enoent:
        errno = ENOENT;
        return (-1);

 emsgsize:
        errno = EMSGSIZE;
        return (-1);
}

static int
getbits(const char *src, int ipv6) {
        int bits = 0;
        char *cp, ch;

        if (*src == '\0')                       /*%< syntax */
                return (-2);
        do {
                ch = *src++;
                cp = strchr(digits, ch);
                if (cp == NULL)                 /*%< syntax */
                        return (-2);
                bits *= 10;
                bits += (int)(cp - digits);
                if (bits == 0 && *src != '\0')  /*%< no leading zeros */
                        return (-2);
                if (bits > (ipv6 ? 128 : 32))   /*%< range error */
                        return (-2);
        } while (*src != '\0');

        return (bits);
}

#undef inet_cidr_pton
#pragma weak inet_cidr_pton = __inet_cidr_pton