/*
 *  Copyright (c) 2009-2022, Peter Haag
 *  Copyright (c) 2008-2008, SWITCH - Teleinformatikdienste fuer Lehre und Forschung
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 *   * Neither the name of the author nor the names of its contributors may be
 *     used to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright (c) 1996 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 <arpa/nameser.h>
#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>

#include "config.h"

#ifdef HAVE_RESOLV_H
#include <resolv.h>
#endif

#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif

#include "ipconv.h"
#include "nfdump.h"
#include "nffile.h"
#include "util.h"

static int parse_ipv4(const char *src, uint32_t *dst, int *bytes);
static int parse_ipv6(const char *src, uint64_t *dst, int *bytes);
static int lookup_host(const char *hostname, uint64_t *iplist, uint32_t *num_ip);

int parse_ip(int *af, const char *src, uint64_t *dst, int *bytes, int lookup, uint32_t *num_ip) {
    char *alpha = "abcdefghijklmnopqrstuvwxzyABCDEFGHIJKLMNOPQRSTUVWXZY";
    uint32_t v4addr;
    int ret;

    // check for IPv6 address
    if (strchr(src, ':') != NULL) {
        *af = PF_INET6;
        // check for alpha chars -> hostname -> lookup
    } else if (strpbrk(src, alpha)) {
        *af = 0;
        if (lookup == STRICT_IP)
            return -1;
        else
            return lookup_host(src, dst, num_ip);
        // it's IPv4
    } else
        *af = PF_INET;

    *num_ip = 1;
    switch (*af) {
        case AF_INET:
            ret = (parse_ipv4(src, &v4addr, bytes));
            dst[0] = 0;
            dst[1] = ntohl(v4addr) & 0xffffffffLL;
            return ret;
            break;
        case AF_INET6:
            ret = (parse_ipv6(src, dst, bytes));
            dst[0] = ntohll(dst[0]);
            dst[1] = ntohll(dst[1]);
            return ret;
            break;
    }
    /* NOTREACHED */

    return 0;
}

static int parse_ipv4(const char *src, uint32_t *dst, int *bytes) {
    static const char digits[] = "0123456789";
    int saw_digit, ch;
    uint8_t tmp[4], *tp;

    saw_digit = 0;
    *bytes = 0;
    *(tp = tmp) = 0;
    memset(tmp, 0, sizeof(tmp));
    while ((ch = *src++) != '\0') {
        const char *pch;

        if ((pch = strchr(digits, ch)) != NULL) {
            long new = *tp * 10 + (pch - digits);

            if (new > 255) return (0);
            if (!saw_digit) {
                if (++(*bytes) > 4) return (0);
                saw_digit = 1;
            }
            *tp = new;
        } else if (ch == '.' && saw_digit) {
            if (*bytes == 4) return (0);
            *++tp = 0;
            saw_digit = 0;
            if (!(*src)) return 0;
        } else
            return (0);
    }

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

static int parse_ipv6(const char *src, uint64_t *dst, int *bytes) {
    static const char xdigits_l[] = "0123456789abcdef", xdigits_u[] = "0123456789ABCDEF";
    uint8_t tmp[16], *tp, *endp, *colonp;
    const char *xdigits, *curtok;
    int ch, saw_xdigit;
    u_int val;

    memset((tp = tmp), '\0', sizeof(tmp));
    endp = tp + sizeof(tmp);
    colonp = NULL;
    /* Leading :: requires some special handling. */
    if (*src == ':')
        if (*++src != ':') return (0);
    curtok = src;
    saw_xdigit = 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 (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 + sizeof(uint16_t) > endp) return (0);
            *tp++ = (u_char)(val >> 8) & 0xff;
            *tp++ = (u_char)val & 0xff;
            saw_xdigit = 0;
            val = 0;
            continue;
        }
        if (ch == '.' && ((tp + 4) <= endp) && parse_ipv4(curtok, (uint32_t *)tp, bytes) > 0) {
            tp += 4;
            saw_xdigit = 0;
            break; /* '\0' was seen by parse_ipv4(). */
        }
        return (0);
    }
    if (saw_xdigit) {
        if (tp + sizeof(uint16_t) > 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 long n = tp - colonp;
        int i;

        for (i = 1; i <= n; i++) {
            endp[-i] = colonp[n - i];
            colonp[n - i] = 0;
        }
        tp = endp;
    }
    *bytes = 16 - (endp - tp);

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

static int lookup_host(const char *hostname, uint64_t *iplist, uint32_t *num_ip) {
    struct addrinfo hints, *res, *r;
    int errcode, i, len;
    char addrstr[128];
    char reverse[256];
    void *ptr;

    printf("Resolving %s ...\n", hostname);

    memset(&hints, 0, sizeof(hints));
    hints.ai_family = PF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags |= AI_CANONNAME;

    errcode = getaddrinfo(hostname, NULL, &hints, &res);
    if (errcode != 0) {
        fprintf(stderr, "Failed to resolve IP address for %s: %s\n", hostname, gai_strerror(errno));
        return 0;
    }

    // count the number of records found
    *num_ip = 0;

    // remember res for later free()
    r = res;

    i = 0;
    while (res) {
        if (*num_ip >= MAXHOSTS) {
            printf("Too man IP addresses in DNS response\n");
            return 1;
        }
        switch (res->ai_family) {
            case PF_INET:
                ptr = &(((struct sockaddr_in *)res->ai_addr)->sin_addr);
                iplist[i++] = 0;
                iplist[i++] = ntohl(*(uint32_t *)ptr) & 0xffffffffLL;
                len = sizeof(struct sockaddr_in);
                break;
            case AF_INET6:
                ptr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
                iplist[i++] = ntohll(((uint64_t *)ptr)[0]);
                iplist[i++] = ntohll(((uint64_t *)ptr)[1]);
                len = sizeof(struct sockaddr_in6);
                break;
            default: {
                // not handled
                res = res->ai_next;
                continue;
            }
        }
        inet_ntop(res->ai_family, ptr, addrstr, 100);
        addrstr[99] = '\0';
        if ((errcode = getnameinfo(res->ai_addr, len, reverse, sizeof(reverse), NULL, 0, 0)) != 0) {
            snprintf(reverse, sizeof(reverse) - 1, "<reverse lookup failed>");
            // fprintf(stderr, "Failed to reverse lookup %s: %s\n", addrstr, gai_strerror(errcode));
        }

        printf("IPv%d address: %s (%s)\n", res->ai_family == PF_INET6 ? 6 : 4, addrstr, reverse);
        res = res->ai_next;
        (*num_ip)++;
    }

    freeaddrinfo(r);
    return 1;

}  // End of lookup_host

int set_nameserver(char *ns) {
    struct hostent *host;

    res_init();
    host = gethostbyname(ns);
    if (host == NULL) {
        (void)fprintf(stderr, "Can not resolv nameserver %s: %s\n", ns, hstrerror(h_errno));
        return 0;
    }
    (void)memcpy((void *)&_res.nsaddr_list[0].sin_addr, (void *)host->h_addr_list[0], (size_t)host->h_length);
    _res.nscount = 1;
    return 1;

}  // End of set_nameserver

/*
int main( int argc, char **argv ) {

char	*s, t[64];
uint64_t	anyaddr[2];
uint32_t	 num_ip;
int af, ret, bytes;


        s = argv[1];
        if (argc == 3 && !set_nameserver(argv[2]) )
                        return 0;

        lookup_host(s, &num_ip);
        return 0;

        ret = parse_ip(&af, s, anyaddr, &bytes);
        if ( ret != 1 ) {
                printf("Parse failed!\n");
                return 0;
        }

        if ( af == PF_INET )
                inet_ntop(af, &(((uint32_t *)anyaddr)[3]), t, 64);
        else
                inet_ntop(af, anyaddr, t, 64);

        printf("Convert back: %s => %s %i bytes\n", s, t, bytes);

}

*/
