<?php
/** DomFramework
  * @package domframework
  * @author Dominique Fournier <dominique@fournier38.fr>
  */

/** TCP Client
  * Allow to create TCP connections to a server.
  * If both IPv6 and IPv4 are allowed by the server, try in IPv6 then back in
  * IPv4 if it doesn't works.
  * If the name of the server is provided instead of the IP, look for all the
  * IP address, manage the CNAME aliases.
  * If multiple addresses are available in IPv6 or IPv4, randomize them to allow
  * round-robin connections to the server.
  * Manage the timeout, send a command, receive a max number of bytes,
  * allow SSL trafic with CA verification
  */
class tcpclient
{
  //    PROPERTIES    //
  // {{{
  /** The IPv6 allowed for the server
    */
  private $ipv6 = array ();

  /** The IPv4 allowed for the server
    */
  private $ipv4 = array ();

  /** The ipOrName parameter
    */
  private $ipOrName = null;

  /** The port to connect to the server
    */
  private $port = null;

  /** Prefer the IPv4 connection either the IPv6 is valid
    */
  private $preferIPv4 = false;

  /** The internal socket connected to the server
    */
  private $socket = null;

  /** Read in Text mode or in Binary mode
    */
  private $readMode = "text";

  /** The timeout before aborting the connection
    * 30s by default
    */
  private $timeout = 30;
  // }}}

  /** Initialize the object, by setting the name or the IP of the server
    * @param string $ipOrName The IP or the name of the server
    * @param integer $port The port of the server to connect
    */
  public function __construct ($ipOrName, $port)
  // {{{
  {
    $providedIpOrName = $ipOrName;
    if (filter_var ($ipOrName, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4))
      $this->ipv4 = array ($ipOrName);
    elseif (filter_var ($ipOrName, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6))
      $this->ipv6 = array ($ipOrName);
    else
    {
      $i = 0;
      while (empty ($this->ipv4) && empty ($this->ipv6) && $i < 10)
      {
        $nsRecords = @dns_get_record ($ipOrName, DNS_A + DNS_AAAA);
        if ($nsRecords === false || $nsRecords == array ())
        {
          // There is some problems with CNAME if they are not defined.
          // So enter in this case only if there is no other solution
          $nsRecords = @dns_get_record ($ipOrName, DNS_CNAME);
          if ($nsRecords === false || $nsRecords == array ())
            throw new \Exception ("Can not find the IP for $ipOrName : ".
              "DNS Error (No A, AAAA, CNAME entries)", 523);
        }
        foreach ($nsRecords as $val)
        {
          if ($val["type"] === "CNAME")
            $ipOrName = $val["target"];
          elseif ($val["type"] === "A")
            $this->ipv4[] = $val["ip"];
          elseif ($val["type"] === "AAAA")
            $this->ipv6[] = $val["ipv6"];
        }
        $i++;
      }
      if ($i >= 10)
        throw new \Exception ("Can not find the IP for $ipOrName : ".
          "CNAME loop", 404);
      if (empty ($this->ipv4) && empty ($this->ipv6))
        throw new \Exception ("Can not find the IP for $ipOrName : ".
          "No A or AAAA record", 404);
    }
    $port = intval ($port);
    if ($port < 0 || $port > 65535)
      throw new \Exception ("Invalid port provided to connection to server",
        500);
    $this->ipOrName = $providedIpOrName;
    $this->port = $port;
    shuffle ($this->ipv6);
    shuffle ($this->ipv4);
  }
  // }}}

  /** Set/get the preferIPv4 property
    * @param boolean|null $preferIPv4 The preferIPv4 property to set (or to get
    * if null)
    */
  public function preferIPv4 ($preferIPv4 = null)
  // {{{
  {
    if ($preferIPv4 === null)
      return $this->preferIPv4;
    if ($this->socket !== null)
      throw new \Exception ("Can not connect in IPv4 prefered to server ".
        " $this->ipOrName : The server is already connected", 500);
    $this->preferIPv4 = !!$preferIPv4;
    return $this;
  }
  // }}}

  /** Set/get the read mode : text or binary
    * @param string|null $readMode The mode to set (or get if null)
    */
  public function readMode ($readMode = null)
  // {{{
  {
    if ($readMode === null)
      return $this->readMode;
    if ($readMode !== "text" && $readMode !== "binary")
      throw new \Exception ("Invalid readMode provided (nor text nor binary)",
        500);
    $this->readMode = $readMode;
    return $this;
  }
  // }}}

  /** Set/get the timeout
    * @param integer|null $timeout The timeout in seconds
    */
  public function timeout ($timeout = null)
  // {{{
  {
    if ($timeout === null)
      return $this->timeout;
    $this->timeout = intval ($timeout);
    return $this;
  }
  // }}}

  /** Initialize the connection to the server
    * Return the socket
    */
  public function connect ()
  // {{{
  {
    if ($this->preferIPv4)
      $ips = array_merge ($this->ipv4, $this->ipv6);
    else
      $ips = array_merge ($this->ipv6, $this->ipv4);
    foreach ($ips as $ip)
    {
      if (filter_var ($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6))
        $ip = "[$ip]";
      $socket = @stream_socket_client ("tcp://$ip:$this->port", $errno, $errstr,
        $this->timeout);
      if ($socket === false)
        continue;
      $this->socket = $socket;
      return $this->socket;
    }
    if ($errno === 110)
      throw new \Exception ("Can not connect to server $this->ipOrName : ".
        "Connection timed out", 522);
    if ($errno === 111)
      throw new \Exception ("Can not connect to server $this->ipOrName : ".
        "Connection refused", 521);
    if ($errno === 113)
      throw new \Exception ("Can not connect to server $this->ipOrName : ".
        "No route to host", 523);
    throw new \Exception ("Can not connect to server $this->ipOrName : ".
      $errstr, 500);
  }
  // }}}

  /** Activate the SSL connection.
    * Put the socket in blocking mode, as it is mandatory to have SSL connection
    * @param boolean $val True to activate, false to disable SSL
    * @param integer|null $cryptoMethod The cryptoMethod allowed
    * @param array|null $options Can overload the SSL options if needed
    * @return false if the client can not found a encryption method with the
    * server
    */
  public function cryptoEnable ($val, $cryptoMethod = null, $options = array ())
  // {{{
  {
    if ($this->socket === null)
      throw new \Exception ("Can not send to server $this->ipOrName : ".
        "The server is not connected", 500);
    if ($cryptoMethod === null)
      $cryptoMethod = STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT|
                      STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT|
                      STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT;
    $optionsBase = array ("ssl" => array (
      "peer_name" => $this->ipOrName,
      "verify_peer" => true,
      "verify_peer_name" => true,
      "capture_peer_cert" => true,
      "capture_peer_cert_chain" => true,
      "SNI_enabled" => true,
    ));
    $optionsMerged["ssl"] = array_merge ($optionsBase["ssl"], $options);
    stream_set_blocking ($this->socket, true);
    stream_context_set_option ($this->socket, $optionsMerged);
    $php_errormsg = "";
    ini_set ("track_errors", 1);
    $rc = @stream_socket_enable_crypto ($this->socket, !!$val, $cryptoMethod);
    ini_set ("track_errors", 0);
    if ($rc === false)
      throw new \Exception ("Can not enable crypto to '$this->ipOrName' : ".
        substr (strrchr ($php_errormsg, ":"), 1), 500);
    return $rc;
  }
  // }}}

  /** Send a data to the server.
    * The connection must be established
    * @param mixed $data The data to send
    */
  public function send ($data)
  // {{{
  {
    if ($this->socket === null)
      throw new \Exception ("Can not send to server $this->ipOrName : ".
        "The server is not connected", 500);
    stream_set_timeout ($this->socket, $this->timeout);
    $length = strlen ($data);
    $sentLen = @fwrite ($this->socket, $data);
    if ($sentLen < $length)
      throw new \Exception ("Can not send to server $this->ipOrName", 500);
    return $sentLen;
  }
  // }}}

  /** Read the data from the server.
    * The connection must be established
    * Use the readMode in text or binary (text by default)
    * In text mode, the read return when found the first \r\n, and doesn't
    * returns the \r\n.
    * @param integer $maxLength Limit the length of the data from the server
    * @return The content
    */
  public function read ($maxLength = 1024)
  // {{{
  {
    if ($this->socket === null)
      throw new \Exception ("Can not read from server $this->ipOrName : ".
        "The server is not connected", 500);
    stream_set_timeout ($this->socket, $this->timeout);
    if ($this->readMode === "text")
    {
      $read = stream_get_line ($this->socket, $maxLength, "\r\n");
      if ($read === false)
        throw new \Exception ("Can not read from server in text", 500);
    }
    else
    {
      $read = fread ($this->socket, $maxLength);
      if ($read === false)
        throw new \Exception ("Can not read from server in binary" , 500);
    }
    return $read;
  }
  // }}}

  /** Disconnect the socket
    */
  public function disconnect ()
  // {{{
  {
    if ($this->socket === null)
      throw new \Exception ("Can not disconnect server $this->ipOrName : ".
        "The server is not connected", 500);
    @stream_socket_shutdown ($this->socket, STREAM_SHUT_RDWR);
    $this->socket = null;
  }
  // }}}

  /** Get meta data, like the timeout state, the crypto protocol and ciphers...
    */
  public function getMeta ()
  // {{{
  {
    return stream_get_meta_data ($this->socket);
  }
  // }}}

  /** Get the connection peer address, peer port and localaddress and localport
    * @return array
    */
  public function getInfo ()
  // {{{
  {
    if ($this->socket === null)
      throw new \Exception ("Can not getInfo for server $this->ipOrName : ".
        "The server is not connected", 500);
    $name = stream_socket_get_name ($this->socket, false);
    $pos = strrpos ($name, ":");
    $localPort = substr ($name, $pos+1);
    $localAddress = substr ($name, 0, $pos);
    $name = stream_socket_get_name ($this->socket, true);
    $pos = strrpos ($name, ":");
    $port = substr ($name, $pos+1);
    $address = substr ($name, 0, $pos);
    return array ($address, $port, $localAddress, $localPort);
  }
  // }}}

  /** Get the socket to direct access
    * @return resource The socket with the client
    */
  public function getSock ()
  // {{{
  {
    return $this->socket;
  }
  // }}}
}