<?php

require_once 'ykval-config.php';
require_once 'ykval-common.php';
require_once 'lib/Db.php';

class SyncLib
{
  public $syncServers = null;
  public $dbConn = null;

  function __construct()
  {
    global $baseParams;
    $this->syncServers = explode(";", $baseParams['__YKVAL_SYNC_POOL__']);
    $this->db=new Db($baseParams['__YKVAL_DB_HOST__'],
		     $baseParams['__YKVAL_DB_USER__'],
		     $baseParams['__YKVAL_DB_PW__'],
		     $baseParams['__YKVAL_DB_NAME__']);
    $this->db->connect();
    $this->random_key=rand(0,1<<16);
  }

  function DbTimeToUnix($db_time)
  {
    $unix=strptime($db_time, '%F %H:%M:%S');
    return mktime($unix[tm_hour], $unix[tm_min], $unix[tm_sec], $unix[tm_mon]+1, $unix[tm_mday], $unix[tm_year]+1900);
  }
  
  function UnixToDbTime($unix)
  {
    return date('Y-m-d H:i:s', $unix);
  }  
  function getServer($index)
  {
    if (isset($this->syncServers[$index])) return $this->syncServers[$index];
    else return "";
  }
  function getLast() 
  {
    $res=$this->db->last('queue', 1);
    parse_str($res['info'], $info);
    return array('modified'=>$this->DbTimeToUnix($res['modified_time']), 
		 'otp'=>$res['otp'], 
		 'server'=>$res['server'], 
		 'yk_identity'=>$info['yk_identity'], 
		 'yk_counter'=>$info['yk_counter'], 
		 'yk_use'=>$info['yk_use'], 
		 'yk_high'=>$info['yk_high'], 
		 'yk_low'=>$info['yk_low']);
  }
  public function getQueueLength()
  {
    return count($this->db->last('queue', NULL));
  }
  public function queue($modified, $otp, $identity, $counter, $use, $high, $low)
  {
    $info='modified=' . $modified .
      '&otp=' . $otp .
      '&yk_identity=' . $identity .
      '&yk_counter=' . $counter .
      '&yk_use=' . $use .
      '&yk_high=' . $high .
      '&yk_low=' . $low;
    
    $this->otpParams['modified']=$modified;
    $this->otpParams['otp']=$otp;
    $this->otpParams['yk_identity']=$identity;
    $this->otpParams['yk_counter']=$counter;
    $this->otpParams['yk_use']=$use;
    $this->otpParams['yk_high']=$high;
    $this->otpParams['yk_low']=$low;
    
    $res=True;
    foreach ($this->syncServers as $server) {
      
      if(! $this->db->save('queue', array('modified_time'=>$this->UnixToDbTime($modified), 
					  'otp'=>$otp, 
					  'server'=>$server,
					  'random_key'=>$this->random_key,
					  'info'=>$info))) $res=False;
    }
    return $res;
  }
  public function getNumberOfServers()
  {
    if (is_array($this->syncServers)) return count($this->syncServers);
    else return 0;
  }

  private function log($level, $msg, $params=NULL)
  {
    $logMsg="ykval-synclib:" . $level . ":" . $msg;
    if ($params) $logMsg .= " modified=" . $params['modified'] .
		   " yk_identity=" . $params['yk_identity'] .
		   " yk_counter=" . $params['yk_counter'] .   
		   " yk_use=" . $params['yk_use'] .   
		   " yk_high=" . $params['yk_high'] .   
		   " yk_low=" . $params['yk_low'];
    error_log($logMsg);
  }
  private function getLocalParams($yk_identity)
  {
    $this->log("notice", "searching for " . $yk_identity . " (" . modhex2b64($yk_identity) . ") in local db");
    $res = $this->db->lastBy('yubikeys', 'publicName', modhex2b64($yk_identity));
    $localParams=array('modified'=>$this->DbTimeToUnix($res['accessed']),
		       'yk_identity'=>$yk_identity,
		       'yk_counter'=>$res['counter'], 
		       'yk_use'=>$res['sessionUse'],
		       'yk_high'=>$res['high'],
		       'yk_low'=>$res['low']);

    $this->log("notice", "counter found in db ", $localParams);

    return $localParams;

  }

  private function parseParamsFromMultiLineString($str)
  {
      preg_match("/^modified=([0-9]*)/m", $str, $out);
      $resParams['modified']=$out[1];
      preg_match("/^yk_identity=([[:alpha:]]*)/m", $str, $out);
      $resParams['yk_identity']=$out[1];
      preg_match("/^yk_counter=([0-9]*)/m", $str, $out);
      $resParams['yk_counter']=$out[1];
      preg_match("/^yk_use=([0-9]*)/m", $str, $out);
      $resParams['yk_use']=$out[1];
      preg_match("/^yk_high=([0-9]*)/m", $str, $out);
      $resParams['yk_high']=$out[1];
      preg_match("/^yk_low=([0-9]*)/m", $str, $out);
      $resParams['yk_low']=$out[1];

      return $resParams;
  }

  public function updateDbCounters($params)
  {


    $res=$this->db->lastBy('yubikeys', 'publicName', modhex2b64($params['yk_identity']));
    if (isset($res['id'])) {
      if(! $this->db->update('yubikeys', $res['id'], array('accessed'=>$this->UnixToDbTime($params['modified']), 
							   'counter'=>$params['yk_counter'], 
							   'sessionUse'=>$params['yk_use'],
							   'low'=>$params['yk_low'],
							   'high'=>$params['yk_high'])))
	{
	  error_log("ykval-synclib:critical: failed to update internal DB with new counters");
	  return false;
	} else {
	$this->log("notice", "updated database ", $params);
	return true;
      }
    } else return false;
  }
    
  public function countersHigherThan($p1, $p2)
  {
    if ($p1['yk_counter'] > $p2['yk_counter'] ||
	($p1['yk_counter'] == $p2['yk_counter'] &&
	 $p1['yk_use'] > $p2['yk_use'])) return true;
    else return false;
  }
  
  public function countersHigherThanOrEqual($p1, $p2)
  {
    if ($p1['yk_counter'] > $p2['yk_counter'] ||
	($p1['yk_counter'] == $p2['yk_counter'] &&
	 $p1['yk_use'] >= $p2['yk_use'])) return true;
    else return false;
  }
  
  public function sync($ans_req) 
  {
    #
    # Construct URLs
    #

    $urls=array();
    $res=$this->db->findByMultiple('queue', array("modified_time"=>$this->UnixToDbTime($this->otpParams['modified']), "random_key"=>$this->random_key));
    foreach ($res as $row) {
      $urls[]=$row['server'] . '?' . $row['info'];
    }

    #
    # Send out requests
    #
    if (count($urls)>=$ans_req) $ans_arr=$this->retrieveURLasync($urls, $ans_req);
    else return false;

    if (!is_array($ans_arr)) {
      $this->log('warning', 'No responses from validation server pool'); 
      $ans_arr=array();
    }

    #
    # Parse responses
    #
    $localParams=$this->getLocalParams($this->otpParams['yk_identity']);

    $this->answers = count($ans_arr);
    $this->valid_answers = 0;
    foreach ($ans_arr as $answer){
      // Parse out parameters from each response
      $resParams=$this->parseParamsFromMultiLineString($answer);
      $this->log("notice", "local db contains ", $localParams);
      $this->log("notice", "response contains ", $resParams);
      
# Check if internal DB should be updated
      if ($this->countersHigherThan($resParams, $localParams)) {
	$this->updateDbCounters($resParams);
      }
      
# Check for warnings 
      #
# If received sync response have lower counters than locally saved last counters 
      # (indicating that remote server wasn't synced) 
      
      if ($this->countersHigherThan($localParams, $resParams)) {
	$this->log("warning", "Remote server out of sync, local counters ", $localParams);
	$this->log("warning", "Remote server out of sync, remote counters ", $resParams);
      }
      
# If received sync response have higher counters than locally saved last counters 
      # (indicating that local server wasn't synced) 
      if ($this->countersHigherThan($resParams, $localParams)) {
	$this->log("warning", "Local server out of sync, local counters ", $localParams);
	$this->log("warning", "Local server out of sync, remote counters ", $resParams);
      }
      
# If received sync response have higher counters than OTP counters
      # (indicating REPLAYED_OTP) 
      if ($this->countersHigherThanOrEqual($resParams, $this->otpParams)) {
	$this->log("warning", "replayed OTP, remote counters " , $resParams);
	$this->log("warning", "replayed OTP, otp counters", $this->otpParams);
      }

      
# Check if answer marks OTP as valid
      if (!$this->countersHigherThanOrEqual($resParams, $this->otpParams)) $this->valid_answers++;
      
      # Delete entry from table
      preg_match('/url=(.*)\?/', $answer, $out);
      $server=$out[1];
      debug("server=" . $server);
      $this->db->deleteByMultiple('queue', array("modified_time"=>$this->UnixToDbTime($this->otpParams['modified']), "random_key"=>$this->random_key, 'server'=>$server));
      
    }
   
    /* Return true if valid answers equals required answers. Since we only obtain the required
     amount of answers from retrieveAsync this indicates that all answers were actually valid. 
     Otherwise, return false. */
    if ($this->valid_answers==$ans_req) return True;
    else return False;
  }
  public function getNumberOfValidAnswers()
  {
    if (isset($this->valid_answers)) return $this->valid_answers;
    else return 0;
  }
  public function getNumberOfAnswers()
  {
    if (isset($this->answers)) return $this->answers;
    else return 0;
  }


// This function takes a list of URLs.  It will return the content of
// the first successfully retrieved URL, whose content matches ^OK.
// The request are sent asynchronously.  Some of the URLs can fail
// with unknown host, connection errors, or network timeout, but as
// long as one of the URLs given work, data will be returned.  If all
// URLs fail, data from some URL that did not match parameter $match 
// (defaults to ^OK) is returned, or if all URLs failed, false.
function retrieveURLasync ($urls, $ans_req=1) {
  $mh = curl_multi_init();

  $ch = array();
  foreach ($urls as $id => $url) {
    $handle = curl_init();

    curl_setopt($handle, CURLOPT_URL, $url);
    curl_setopt($handle, CURLOPT_USERAGENT, "YK-VAL");
    curl_setopt($handle, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($handle, CURLOPT_FAILONERROR, true);
    curl_setopt($handle, CURLOPT_TIMEOUT, 10);

    curl_multi_add_handle($mh, $handle);

    $ch[$handle] = $handle;
  }

  $str = false;
  $ans_count = 0;
  $ans_arr = array();

  do {
    while (($mrc = curl_multi_exec($mh, $active)) == CURLM_CALL_MULTI_PERFORM)
      ;

    while ($info = curl_multi_info_read($mh)) {
      debug ("YK-KSM multi", $info);
      if ($info['result'] == CURL_OK) {
	$str = curl_multi_getcontent($info['handle']);
	debug($str);
	if (preg_match("/status=OK/", $str)) {
	  $error = curl_error ($info['handle']);
	  $errno = curl_errno ($info['handle']);
	  $cinfo = curl_getinfo ($info['handle']);
	  debug("YK-KSM errno/error: " . $errno . "/" . $error, $cinfo);
	  $ans_count++;
	  debug("found entry");
	  $ans_arr[]="url=" . $cinfo['url'] . "\n" . $str;
	}

	if ($ans_count >= $ans_req) {
	  foreach ($ch as $h) {
	    curl_multi_remove_handle ($mh, $h);
	    curl_close ($h);
	  }
	  curl_multi_close ($mh);
	  
	  return $ans_arr;
	}
	
	curl_multi_remove_handle ($mh, $info['handle']);
	curl_close ($info['handle']);
	unset ($ch[$info['handle']]);
      }

      curl_multi_select ($mh);
    }
  } while($active);

  foreach ($ch as $h) {
    curl_multi_remove_handle ($mh, $h);
    curl_close ($h);
  }
  curl_multi_close ($mh);

  return $str;
}

}

?>