/*
* Copyright (C) 2010-2015 Mamadou DIOP.
*
* This file is part of Open Source Doubango Framework.
*
* DOUBANGO is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* DOUBANGO is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with DOUBANGO.
*
*/

/**@file tnet.c
 * @brief Network stack.
 */
#include "tnet.h"
#include "tnet_utils.h"
#include "tnet_proxy_node_socks_plugin.h"
#include "tnet_proxy_plugin.h"

#include "tsk_time.h"
#include "tsk_debug.h"

#include <stdlib.h> /* srand */

#if HAVE_OPENSSL
#	include <openssl/ssl.h>
#endif

/** @mainpage tinyNET API Overview
*
* <h1>10 Sockets and Network Functions</h1>
*
* All network functions are part of tinyNET projects.<br>
* You MUST call @ref tnet_startup() before using any network function (tnet_*). tnet_cleanup() is used to terminate use of network functions. <br>
* The startup function will determine whether the host is a little-endian machine or not (at runtime).
*
* ======
*
* - @ref tnet_socket_group
* - @ref tnet_utils_group
* - @ref tnet_dhcp_group
* - @ref tnet_dhcp6_group
* - @ref tnet_dns_group
* - @ref tnet_nat_group (@ref tnet_stun_group, @ref tnet_turn_group, ICE)
*
* ======
*
* <table>
* <tr> <td><b>LDFLAGS</b></td> <td>-ltinySAK</td> </tr>
* <tr> <td><b>CFLAGS</b></td> <td>-Isrc -ItinySAK/src</td> </tr>
* </table>
*
*/
static tsk_bool_t __tnet_started = tsk_false;
tsk_bool_t tnet_isBigEndian = tsk_false;

/**
 * @fn tnet_startup
 * This is probably the most important function. You MUST call this function to initialize the network stack before calling any <b>tnet_*</b> function. <br />
 * On windows, this function will call <a target=_blank href="http://msdn.microsoft.com/en-us/library/windows/desktop/ms742213(v=vs.85).aspx">WSAStartup</a>. <br />
 * You MUST call @ref tnet_cleanup to cleanup the network stack if you no longer need to use networking function.
 *
 * @sa @ref tnet_cleanup.
 * @return 0 if succeed and error code otherwise.
**/
int tnet_startup()
{
    int err = 0;
    short word = 0x4321;

    if (__tnet_started) {
        goto bail;
    }

    if ((err = tnet_proxy_node_plugin_register(tnet_proxy_node_socks_plugin_def_t)) != 0) {
        goto bail;
    }

    // rand()
    srand((unsigned int) tsk_time_epoch());

    // endianness
    tnet_isBigEndian = ((*(int8_t *)&word) != 0x21);
#if TNET_UNDER_WINDOWS
    if (tnet_isBigEndian) {
        TSK_DEBUG_ERROR("Big endian on Windows machine. Is it right?");
    }
#endif
    // Print messages regardless the debug level
#if TNET_UNDER_WINDOWS_CE && (BUILD_TYPE_GE && SIN_CITY)
#	define PRINT_INFO TSK_DEBUG_INFO
#	define PRINT_ERROR TSK_DEBUG_ERROR
#else
#	define PRINT_INFO(FMT, ...) fprintf(stdout, FMT "\n", ##__VA_ARGS__)
#	define PRINT_ERROR(FMT, ...) fprintf(stderr, FMT "\n", ##__VA_ARGS__)
#endif

#if TNET_UNDER_WINDOWS
    {
        WORD wVersionRequested;
        WSADATA wsaData;

        wVersionRequested = MAKEWORD(2, 2);

        err = WSAStartup(wVersionRequested, &wsaData);
        if (err != 0) {
            PRINT_ERROR("WSAStartup failed with error: %d", err);
            return -1;
        }

        if (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2) {
            PRINT_ERROR("Could not find a usable version of Winsock.dll");
            tnet_cleanup();
            return -2;
        }
        else {
            PRINT_INFO("The Winsock 2.2 dll was found okay");
        }
    }
#endif /* TNET_UNDER_WINDOWS */

#if HAVE_OPENSSL
    PRINT_INFO("SSL is enabled :)");
    SSL_library_init();
    OpenSSL_add_all_algorithms();
    SSL_load_error_strings();

    PRINT_INFO("DTLS supported: %s", tnet_dtls_is_supported() ? "yes" : "no");
    PRINT_INFO("DTLS-SRTP supported: %s", tnet_dtls_is_srtp_supported() ? "yes" : "no");
#else
    PRINT_ERROR("SSL is disabled :(");
#endif

    __tnet_started = tsk_true;

bail:
    return err;
}


/**
 * Cleanup the network stack. <br />
 * On windows, this function will call <a target=_blank href="http://msdn.microsoft.com/en-us/library/windows/desktop/ms741549(v=vs.85).aspx">WSACleanup</a>. <br />
 * @sa @ref tnet_startup.
 * @return 0 if succeed and non-zero error code otherwise.
**/
int tnet_cleanup()
{
    if (!__tnet_started) {
        goto bail;
    }

    tnet_proxy_node_plugin_unregister(tnet_proxy_node_socks_plugin_def_t);

#if TNET_UNDER_WINDOWS
    __tnet_started = tsk_false;
    return WSACleanup();
#else
    __tnet_started = tsk_false;
#endif

bail:
    return 0;
}