/*

 * Copyright (c) 2015 DeNA Co., Ltd., Kazuho Oku

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#ifndef h2o__hostinfo_h

#define h2o__hostinfo_h

#include <arpa/inet.h>

#include <netdb.h>

#include <netinet/in.h>

#include <stdlib.h>

#include <string.h>

#include <sys/socket.h>

#include <sys/types.h>

#include "h2o/multithread.h"

/* generic errors (https://tools.ietf.org/html/rfc8499#section-3) */

extern const char h2o_hostinfo_error_nxdomain[];

extern const char h2o_hostinfo_error_nodata[];

extern const char h2o_hostinfo_error_refused[];

extern const char h2o_hostinfo_error_servfail[];

/* errors specfic to getaddrinfo */

extern const char h2o_hostinfo_error_gai_addrfamily[];

extern const char h2o_hostinfo_error_gai_badflags[];

extern const char h2o_hostinfo_error_gai_family[];

extern const char h2o_hostinfo_error_gai_memory[];

extern const char h2o_hostinfo_error_gai_service[];

extern const char h2o_hostinfo_error_gai_socktype[];

extern const char h2o_hostinfo_error_gai_system[];

extern const char h2o_hostinfo_error_gai_other[];

typedef struct st_h2o_hostinfo_getaddr_req_t h2o_hostinfo_getaddr_req_t;

typedef void (*h2o_hostinfo_getaddr_cb)(h2o_hostinfo_getaddr_req_t *req, const char *errstr, struct addrinfo *res, void *cbdata);

extern size_t h2o_hostinfo_max_threads;

/**

 * dispatches a (possibly) asynchronous hostname lookup

 */

h2o_hostinfo_getaddr_req_t *h2o_hostinfo_getaddr(h2o_multithread_receiver_t *receiver, h2o_iovec_t name, h2o_iovec_t serv,

                                                 int family, int socktype, int protocol, int flags, h2o_hostinfo_getaddr_cb cb,

                                                 void *cbdata);

/**

 * cancels the request

 */

void h2o_hostinfo_getaddr_cancel(h2o_hostinfo_getaddr_req_t *req);

/**

 * function that receives and dispatches the responses

 */

void h2o_hostinfo_getaddr_receiver(h2o_multithread_receiver_t *receiver, h2o_linklist_t *messages);

/**

 * select one entry at random from the response

 */

static struct addrinfo *h2o_hostinfo_select_one(struct addrinfo *res);

/**

 * equiv. to inet_pton(AF_INET4)

 */

int h2o_hostinfo_aton(h2o_iovec_t host, struct in_addr *addr);

/* inline defs */

inline struct addrinfo *h2o_hostinfo_select_one(struct addrinfo *res)

{

    if (res->ai_next == NULL)

        return res;

    /* count the number of candidates */

    size_t i = 0;

    struct addrinfo *ai = res;

    do {

        ++i;

    } while ((ai = ai->ai_next) != NULL);

    /* choose one, distributed by rand() :-p */

    i = rand() % i;

    for (ai = res; i != 0; ai = ai->ai_next, --i)

        ;

    return ai;

}

#endif