/*
 * 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 <arpa/inet.h>
#include <netinet/in.h>

#include "api.h"

#ifndef NS_INADDRSZ
#define NS_INADDRSZ 4
#endif
#ifndef NS_IN6ADDRSZ
#define NS_IN6ADDRSZ 16
#endif
#ifndef NS_INT16SZ
#define NS_INT16SZ 2
#endif

/* int inet_pton4(src, dst)
 *    like inet_aton() but without all the hexadecimal, octal (with the
 *    exception of 0) 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.
 */
int inet_pton4(const char* src, size_t len, void* dstp) {
    unsigned char* dst = (unsigned char*)dstp;
    const char* end    = src + len;
    int saw_digit, octets, ch;
    unsigned char tmp[NS_INADDRSZ], *tp;

    saw_digit   = 0;
    octets      = 0;
    *(tp = tmp) = 0;
    while (src < end && (ch = *src++) != '\0') {
        if (ch >= '0' && ch <= '9') {
            uint32_t new = *tp * 10 + (ch - '0');

            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;
    memcpy(dst, tmp, NS_INADDRSZ);
    return 1;
}

static int tolower(char c) {
    return c >= 'A' && c < 'Z' ? c + ('a' - 'A') : c;
}

/* 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.
 */
int inet_pton6(const char* src, size_t len, void* dstp) {
    unsigned char* dst          = (unsigned char*)dstp;
    const char* end             = src + len;
    static const char xdigits[] = "0123456789abcdef";
    unsigned char tmp[NS_IN6ADDRSZ];
    unsigned char* tp;
    unsigned char* endp;
    unsigned char* colonp;
    const char* curtok;
    int ch, saw_xdigit;
    unsigned int val;

    tp     = memset(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;
    while (src < end && (ch = tolower(*src++)) != '\0') {
        const char* pch;

        pch = strchr(xdigits, ch);
        if (pch != NULL) {
            val <<= 4;
            val |= (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++      = (unsigned char)(val >> 8) & 0xff;
            *tp++      = (unsigned char)val & 0xff;
            saw_xdigit = 0;
            val        = 0;
            continue;
        }
        if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) && inet_pton4(curtok, end - curtok, tp) > 0) {
            tp += NS_INADDRSZ;
            saw_xdigit = 0;
            break; /* '\0' was seen by inet_pton4(). */
        }
        return 0;
    }
    if (saw_xdigit) {
        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 = 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;
}