<?php
/**
 * Extra functionality for PandoraFMS WebSockets.
 *
 * Register here your methods to handle different WebSocket steps.
 * * connected
 * * process
 * * disconnect
 * * tick
 *
 * DO NOT FORGET TO REGISTER THEM TO ws.php!!
 *
 * @category   Websocket
 * @package    Pandora FMS
 * @subpackage Console
 * @version    1.0.0
 * @license    See below
 *
 *    ______                 ___                    _______ _______ ________
 * |   __ \.-----.--.--.--|  |.-----.----.-----. |    ___|   |   |     __|
 * |    __/|  _  |     |  _  ||  _  |   _|  _  | |    ___|       |__     |
 * |___|   |___._|__|__|_____||_____|__| |___._| |___|   |__|_|__|_______|
 *
 * ============================================================================
 * Copyright (c) 2005-2023 Pandora FMS
 * Please see https://pandorafms.com/community/ for full contribution list
 * This program 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 for version 2.
 * This program 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.
 * ============================================================================
 */

use PandoraFMS\Websockets\WSManager;

/*
 * ============================================================================
 * * GOTTY PROTOCOL: PROXY
 * ============================================================================
 */


/**
 * Connects to internal socket.
 *
 * @param WSManager $ws_object Main WebSocket manager object.
 * @param array     $headers   Communication headers.
 * @param string    $to_addr   Target address (internal).
 * @param integer   $to_port   Target port (internal).
 * @param string    $to_url    Target url (internal).
 *
 * @return socket Active socket or null.
 */
function connectInt(
    WSManager $ws_object,
    array $headers,
    string $to_addr,
    int $to_port,
    string $to_url
) {
    $intSocket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
    // Not sure.
    $connect = socket_connect(
        $intSocket,
        $to_addr,
        $to_port
    );

    if ($connect === false) {
        $ws_object->stderr(socket_last_error($intSocket));
        return null;
    }

    $c_str = 'GET '.$to_url." HTTP/1.1\r\n";
    $c_str .= 'Host: '.$to_addr."\r\n";
    $c_str .= "Upgrade: websocket\r\n";
    $c_str .= "Connection: Upgrade\r\n";
    $c_str .= 'Origin: http://'.$to_addr."\r\n";
    $c_str .= 'Sec-WebSocket-Key: '.$headers['Sec-WebSocket-Key']."\r\n";
    $c_str .= 'Sec-WebSocket-Version: '.$headers['Sec-WebSocket-Version']."\r\n";
    if (isset($headers['Sec-WebSocket-Protocol']) === true) {
        $c_str .= 'Sec-WebSocket-Protocol: '.$headers['Sec-WebSocket-Protocol']."\r\n";
    }

    $c_str .= "\r\n";

    // Send.
    // Register user - internal.
    $intUser = new $ws_object->userClass('INTERNAL-'.uniqid('u'), $intSocket);

    $intUser->headers = [
        'get'                    => $to_url.' HTTP/1.1',
        'host'                   => $to_addr,
        'origin'                 => $to_addr,
        'sec-websocket-protocol' => 'gotty',
    ];

    $ws_object->writeSocket($intUser, $c_str);

    return $intUser;
}


/**
 * Process a connected step on proxied protocols.
 *
 * @param WSManager $ws_object Main WebSocket manager object.
 * @param User      $user      WebSocketUser.
 *
 * @return void
 */
function proxyConnected(
    $ws_object,
    $user
) {
    global $config;

    /*
     * $user->redirect is connected to internal (reflexive).
     * $user->socket is connected to external.
     */

    $failed = false;

    // Gotty. Based on the command selected, redirect to a target port.
    if ($user->requestedResource === '/ssh') {
        $port = $config['gotty_ssh_port'];
    } else if ($user->requestedResource === '/telnet') {
        $port = $config['gotty_telnet_port'];
    } else {
        $failed = true;
    }

    if ($failed === true
        || isset($config['gotty_host']) === false
        || isset($port) === false
    ) {
        $ws_object->disconnect($user->socket);
        return;
    }

    // Switch between ports...
    // Create a new socket connection (internal).
    $intUser = connectInt(
        $ws_object,
        $ws_object->rawHeaders,
        $config['gotty_host'],
        $port,
        '/ws'
    );

    if ($intUser === null) {
        $ws_object->disconnect($user->socket);
        return;
    }

    // Map user.
    $user->intUser = $intUser;
    // And socket.
    $user->intSocket = $intUser->socket;
    $user->redirect = $intUser;
    $intUser->redirect = $user;

    // Keep an eye on changes.
    $ws_object->remoteSockets[$intUser->id] = $intUser->socket;
    $ws_object->remoteUsers[$intUser->id] = $intUser;

    // Ignore. Cleanup socket.
    $ws_object->readSocket($user->intUser);
}


/**
 * Redirects input from user to redirection stabished.
 *
 * @param WSManager     $ws_object Main WebSocket manager object.
 * @param WebSocketUser $user      WebSocket user.
 * @param string        $buffer    Buffer.
 *
 * @return boolean Ok or not.
 */
function proxyProcessRaw($ws_object, $user, $buffer)
{
    if (isset($user->redirect) !== true) {
        $ws_object->disconnect($user->socket);
        return false;
    }

    $ws_object->stderr($user->id.' >> '.$user->redirect->id);
    $ws_object->stderr($ws_object->dump($buffer));
    $ws_object->writeSocket($user->redirect, $buffer);

    return true;
}


/*
 * ============================================================================
 * * ENDS: GOTTY PROTOCOL: PROXY
 * ============================================================================
 */