/*      $OpenBSD: inet_net_pton.c,v 1.14 2022/12/27 17:10:06 jmc Exp $  */

/*
 * Copyright (c) 2012 by Gilles Chehade <gilles@openbsd.org>
 * Copyright (c) 1996,1999 by Internet Software Consortium.
 *
 * SPDX-License-Identifier: ISC
 *
 * 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 "port_before.h"

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

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "port_after.h"

static int      inet_net_pton_ipv4(const char *, u_char *, size_t);
static int      inet_net_pton_ipv6(const char *, u_char *, size_t);

/*
 * static int
 * inet_net_pton(af, src, dst, size)
 *      convert network number from presentation to network format.
 *      accepts hex octets, hex strings, decimal octets, and /CIDR.
 *      "size" is in bytes and describes "dst".
 * return:
 *      number of bits, either imputed classfully or specified with /CIDR,
 *      or -1 if some failure occurred (check errno).  ENOENT means it was
 *      not a valid network specification.
 * author:
 *      Paul Vixie (ISC), June 1996
 */
int
inet_net_pton(int af, const char *src, void *dst, size_t size)
{
        switch (af) {
        case AF_INET:
                return (inet_net_pton_ipv4(src, dst, size));
        case AF_INET6:
                return (inet_net_pton_ipv6(src, dst, size));
        default:
                errno = EAFNOSUPPORT;
                return (-1);
        }
}

/*
 * static int
 * inet_net_pton_ipv4(src, dst, size)
 *      convert IPv4 network number from presentation to network format.
 *      accepts hex octets, hex strings, decimal octets, and /CIDR.
 *      "size" is in bytes and describes "dst".
 * return:
 *      number of bits, either imputed classfully or specified with /CIDR,
 *      or -1 if some failure occurred (check errno).  ENOENT means it was
 *      not an IPv4 network specification.
 * note:
 *      network byte order assumed.  this means 192.5.5.240/28 has
 *      0b11110000 in its fourth octet.
 * author:
 *      Paul Vixie (ISC), June 1996
 */
static int
inet_net_pton_ipv4(const char *src, u_char *dst, size_t size)
{
        static const char
                xdigits[] = "0123456789abcdef",
                digits[] = "0123456789";
        int n, ch, tmp, dirty, bits;
        const u_char *odst = dst;

        ch = (unsigned char)*src++;
        if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
            && isascii((unsigned char)src[1]) && isxdigit((unsigned char)src[1])) {
                /* Hexadecimal: Eat nybble string. */
                if (size == 0)
                        goto emsgsize;
                tmp = 0, dirty = 0;
                src++;  /* skip x or X. */
                while ((ch = (unsigned char)*src++) != '\0' &&
                    isascii(ch) && isxdigit(ch)) {
                        if (isupper(ch))
                                ch = tolower(ch);
                        n = strchr(xdigits, ch) - xdigits;
                        assert(n >= 0 && n <= 15);
                        if (dirty == 0)
                                tmp = n;
                        else
                                tmp = (tmp << 4) | n;
                        if (++dirty == 2) {
                                if (size-- == 0)
                                        goto emsgsize;
                                *dst++ = (u_char) tmp;
                                dirty = 0;
                        }
                }
                if (dirty) {  /* Odd trailing nybble? */
                        if (size-- == 0)
                                goto emsgsize;
                        *dst++ = (u_char) (tmp << 4);
                }
        } else if (isascii(ch) && isdigit(ch)) {
                /* Decimal: eat dotted digit string. */
                for (;;) {
                        tmp = 0;
                        do {
                                n = strchr(digits, ch) - digits;
                                assert(n >= 0 && n <= 9);
                                tmp *= 10;
                                tmp += n;
                                if (tmp > 255)
                                        goto enoent;
                        } while ((ch = (unsigned char)*src++) != '\0' &&
                                 isascii(ch) && isdigit(ch));
                        if (size-- == 0)
                                goto emsgsize;
                        *dst++ = (u_char) tmp;
                        if (ch == '\0' || ch == '/')
                                break;
                        if (ch != '.')
                                goto enoent;
                        ch = (unsigned char)*src++;
                        if (!isascii(ch) || !isdigit(ch))
                                goto enoent;
                }
        } else
                goto enoent;

        bits = -1;
        if (ch == '/' && isascii((unsigned char)src[0]) &&
            isdigit((unsigned char)src[0]) && dst > odst) {
                /* CIDR width specifier.  Nothing can follow it. */
                ch = (unsigned char)*src++;     /* Skip over the /. */
                bits = 0;
                do {
                        n = strchr(digits, ch) - digits;
                        assert(n >= 0 && n <= 9);
                        bits *= 10;
                        bits += n;
                        if (bits > 32)
                                goto emsgsize;
                } while ((ch = (unsigned char)*src++) != '\0' &&
                         isascii(ch) && isdigit(ch));
                if (ch != '\0')
                        goto enoent;
        }

        /* Fiery death and destruction unless we prefetched EOS. */
        if (ch != '\0')
                goto enoent;

        /* If nothing was written to the destination, we found no address. */
        if (dst == odst)
                goto enoent;
        /* If no CIDR spec was given, infer width from net class. */
        if (bits == -1) {
                if (*odst >= 240)       /* Class E */
                        bits = 32;
                else if (*odst >= 224)  /* Class D */
                        bits = 4;
                else if (*odst >= 192)  /* Class C */
                        bits = 24;
                else if (*odst >= 128)  /* Class B */
                        bits = 16;
                else                    /* Class A */
                        bits = 8;
                /* If imputed mask is narrower than specified octets, widen. */
                if (bits < ((dst - odst) * 8))
                        bits = (dst - odst) * 8;
        }
        /* Extend network to cover the actual mask. */
        while (bits > ((dst - odst) * 8)) {
                if (size-- == 0)
                        goto emsgsize;
                *dst++ = '\0';
        }
        return (bits);

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

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


static int
inet_net_pton_ipv6(const char *src, u_char *dst, size_t size)
{
        struct in6_addr  in6;
        int              ret;
        int              bits;
        size_t           bytes;
        char             buf[INET6_ADDRSTRLEN + sizeof("/128")];
        char            *sep;
        const char      *errstr;

        if (strlcpy(buf, src, sizeof buf) >= sizeof buf) {
                errno = EMSGSIZE;
                return (-1);
        }

        sep = strchr(buf, '/');
        if (sep != NULL)
                *sep++ = '\0';

        ret = inet_pton(AF_INET6, buf, &in6);
        if (ret != 1)
                return (-1);

        if (sep == NULL)
                bits = 128;
        else {
                bits = strtonum(sep, 0, 128, &errstr);
                if (errstr) {
                        errno = EINVAL;
                        return (-1);
                }
        }

        bytes = (bits + 7) / 8;
        if (bytes > size) {
                errno = EMSGSIZE;
                return (-1);
        }
        memcpy(dst, &in6.s6_addr, bytes);
        return (bits);
}

/*
 * Weak aliases for applications that use certain private entry points,
 * and fail to include <arpa/inet.h>.
 */
#undef inet_net_pton
__weak_reference(__inet_net_pton, inet_net_pton);