OpenDKIM_RecordCreator

<?php

/**
 * Replace '\n' with "\n". The escape sequence is not recognized when you use '.
 * For the question of how to write line endings, see the note here. 
 * Basically, different operating systems have different conventions for line endings. 
 * Windows uses "\r\n", unix based operating systems use "\n". 
 * You should stick to one convention (I'd chose "\n") and open your file in binary mode (fopen should get "wb", not "w").
 */

/**
 *  DKIMHelper
 *  Used to create keys (using opendkim-keygen) and add entries to KeyTable and SigningTable
 */

class DKIMHelper {

    //Selector for DKIM record
    public $selector;
    //Domain name for DKIM record ex. domain.com
    public $domain;

    //Path to DKIM Base Directory
    public static $OPENDKIM_BASE_DIRECTORY = "G://opt//opendkim//";
    //Name of Keytable
    public static $OPENDKIM_KEY_TABLE = "KeyTable";
    //Name of SigningTable
    public static $OPENDKIM_SIGNING_TABLE = "SigningTable";
    //Name of keys directory for storing folders and private key for use with DKIM
    public static $OPENDKIM_KEY_DIRECTORY = "keys";

    public function __construct($selector, $domain) {
        $this->selector = $selector;
        $this->domain = $domain;
        echo "Creating Folder structure\n";
        $this->_createDKIMKeyFolder();
        echo "Adding Key Table Entry\n";
        $this->_addKeyTableEntry();
        echo "Adding Signing Table Entry\n";
        $this->_addSigningTableEntry();
        // echo $this->getDKIMValue();
        // $this->enableDKIM();
        // $this->disableDKIM();
        // $this->removeDKIM();
    }

    private function _isValidDomain() {

    }

    /**
     *  getDKIMValue - returns the contents of keys/example.com/selector.txt contents(which is the actual DKIM record value.)     
     */
    public function getDKIMValue() {
        $filePath = $this->_getKeyFolderPath()."//".$this->selector.".txt";
        $contents = file_get_contents($filePath);
        // echo $contents;
        return $contents;
    }

    /**
     *  _addKeyTableEntry - add a DKIM Key Table Entry to KeyTable file if none exists.
     *
     */
    //key table entry format : mail._domainkey.example.com example.com:mail:/etc/opendkim/keys/example.com/mail.private
    private function _addKeyTableEntry() {
        $keyTableFile = fopen(self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_KEY_TABLE, "a+");
        // print_r(stream_get_meta_data($keyTableFile));
        while(!feof($keyTableFile)) {
            $line = fgets($keyTableFile);
            $offset = strpos($line, $this->_getKeyTableEntryRecord());
            if($offset !== FALSE) {
                //found the key
                //do nothing if key found.
                break;
            }
        }
        if($offset === FALSE) {
            //lets add it 
            //move to end
            fseek($keyTableFile, 0, SEEK_END);
            flock($keyTableFile, LOCK_EX);
            fwrite($keyTableFile, "\n");
            //add metadata if necessary.
            //append data
            fputs($keyTableFile, $this->_getKeyTableEntryRecord());
            fwrite($keyTableFile, "\n");
            flock($keyTableFile, LOCK_UN);
            //close 
        }

        fclose($keyTableFile);
    }

    public function enableDKIM() {
        //enable DKIM Records?
        $this->_enableDKIMKeyTableFile();
        $this->_enableDKIMSigningTableFile();
    }

    public function disableDKIM() {
        $this->_disableDKIMKeyTableFile();
        $this->_disableDKIMSigningTableFile();
    }

    private function _enableDKIMKeyTableFile() {
        $keyTableFile = fopen(self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_KEY_TABLE, "c+");
        // print_r(stream_get_meta_data($keyTableFile));
        while(!feof($keyTableFile)) {
            $line = fgets($keyTableFile);
            $offset = strpos($line, $this->_getKeyTableEntryRecord());
            if($offset !== FALSE) {
                //found the key
                //do nothing if key found.
                break;
            }
        }
        $cursorPosition = ftell($keyTableFile);
        //move cursor position to starrt of line
        $cursorPosition = $cursorPosition - strlen($line);
        fseek($keyTableFile, $cursorPosition, SEEK_SET);
        $disabledOffset = strpos($line, "#");
        // echo fread($keyTableFile, 15);
        //if disabledOffset = FALSE then item is not disabled
        if($disabledOffset === FALSE) {
            // do nothing
            echo "Already Enabled\n";
        } else {
            echo "Writing data to file \n";
            //get a lock on file before editing
            $lineLength = strlen($line);
            $line = preg_replace("/./", " ", $line);
            //fwrite and flock are used since this file can be accessed by multiple processes at once
            //updation by other process should not result in our changes being lost so we get a exclusive write to it.
            flock($keyTableFile, LOCK_EX);
            fwrite($keyTableFile, $line, $lineLength);
            fseek($keyTableFile, $cursorPosition, SEEK_SET);
            fwrite($keyTableFile, $this->_getKeyTableEntryRecord());
            flock($keyTableFile, LOCK_UN);
            
        }
        fclose($keyTableFile);
    }

    private function _disableDKIMKeyTableFile() {
        //disable DKIM records.
        $keyTableFile = fopen(self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_KEY_TABLE, "c+");
        // print_r(stream_get_meta_data($keyTableFile));
        while(!feof($keyTableFile)) {
            $line = fgets($keyTableFile);
            $offset = strpos($line, $this->_getKeyTableEntryRecord());
            if($offset !== FALSE) {
                //found the key
                //do nothing if key found.
                break;
            }
        }
        $cursorPosition = ftell($keyTableFile);
        //move cursor position to starrt of line
        $cursorPosition = $cursorPosition - strlen($line);
        fseek($keyTableFile, $cursorPosition, SEEK_SET);
        $disabledOffset = strpos($line, "#");
        // echo fread($keyTableFile, 15);
        //if disabledOffset = FALSE then item is not disabled
        if($disabledOffset === FALSE) {
            // do nothing
            //get a lock on file before editing
            $lineLength = strlen($line);
            $line = preg_replace("/./", " ", $line);
            //fwrite and flock are used since this file can be accessed by multiple processes at once
            //updation by other process should not result in our changes being lost so we get a exclusive write to it.
            flock($keyTableFile, LOCK_EX);
            fwrite($keyTableFile, $line, $lineLength);
            fseek($keyTableFile, $cursorPosition, SEEK_SET);
            fwrite($keyTableFile, '#'.$this->_getKeyTableEntryRecord());
            flock($keyTableFile, LOCK_UN);
        } else {
            
        }
        fclose($keyTableFile);
    }

    private function _getKeyTableEntryRecord() {
        return $this->selector."._domainkey.".$this->domain." ".$this->domain.":".$this->selector.":".$this->_getKeyFolderPath()."/".$this->selector.".private";
    }

    private function _addSigningTableEntry() {
        $signingTableFile = fopen(self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_SIGNING_TABLE, "a+");
        while(!feof($signingTableFile)) {
            $line = fgets($signingTableFile);
            $offset = strpos($line, $this->_getSigningTableEntryRecord());
            if($offset !== FALSE) {
                //found the key
                //do nothing if key found.
                break;
            }
        }
        if($offset === FALSE) {
            //lets add it 
            //move to end
            fseek($signingTableFile, 0, SEEK_END);
            flock($signingTableFile, LOCK_EX);
            fwrite($signingTableFile, "\n");
            //append data
            fputs($signingTableFile, $this->_getSigningTableEntryRecord());
            fwrite($signingTableFile, "\n");
            flock($signingTableFile, LOCK_UN);
            //close 
        }

        fclose($signingTableFile);
    }

    private function _enableDKIMSigningTableFile() {
        $signingTableFile = fopen(self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_SIGNING_TABLE, "c+");
        // print_r(stream_get_meta_data($signingTableFile));
        while(!feof($signingTableFile)) {
            $line = fgets($signingTableFile);
            $offset = strpos($line, $this->_getSigningTableEntryRecord());
            if($offset !== FALSE) {
                //found the key
                //do nothing if key found.
                break;
            }
        }
        $cursorPosition = ftell($signingTableFile);
        //move cursor position to starrt of line
        $cursorPosition = $cursorPosition - strlen($line);
        fseek($signingTableFile, $cursorPosition, SEEK_SET);
        $disabledOffset = strpos($line, "#");
        // echo fread($signingTableFile, 15);
        //if disabledOffset = FALSE then item is not disabled
        if($disabledOffset === FALSE) {
            // do nothing
            echo "Already Enabled\n";
        } else {
            echo "Writing data to file \n";
            //get a lock on file before editing
            $lineLength = strlen($line);
            $line = preg_replace("/./", " ", $line);
            //fwrite and flock are used since this file can be accessed by multiple processes at once
            //updation by other process should not result in our changes being lost so we get a exclusive write to it.
            flock($signingTableFile, LOCK_EX);
            fwrite($signingTableFile, $line, $lineLength);
            fseek($signingTableFile, $cursorPosition, SEEK_SET);
            fwrite($signingTableFile, $this->_getSigningTableEntryRecord());
            flock($signingTableFile, LOCK_UN);
            
        }
        fclose($signingTableFile);
    }

    private function _disableDKIMSigningTableFile() {
        //disable DKIM records.
        $signingTableFile = fopen(self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_SIGNING_TABLE, "c+");
        // print_r(stream_get_meta_data($signingTableFile));
        while(!feof($signingTableFile)) {
            $line = fgets($signingTableFile);
            $offset = strpos($line, $this->_getSigningTableEntryRecord());
            if($offset !== FALSE) {
                //found the key
                //do nothing if key found.
                break;
            }
        }
        $cursorPosition = ftell($signingTableFile);
        //move cursor position to starrt of line
        $cursorPosition = $cursorPosition - strlen($line);
        fseek($signingTableFile, $cursorPosition, SEEK_SET);
        $disabledOffset = strpos($line, "#");
        // echo fread($signingTableFile, 15);
        //if disabledOffset = FALSE then item is not disabled
        if($disabledOffset === FALSE) {
            // do nothing
            //get a lock on file before editing
            $lineLength = strlen($line);
            $line = preg_replace("/./", " ", $line);
            //fwrite and flock are used since this file can be accessed by multiple processes at once
            //updation by other process should not result in our changes being lost so we get a exclusive write to it.
            flock($signingTableFile, LOCK_EX);
            fwrite($signingTableFile, $line, $lineLength);
            fseek($signingTableFile, $cursorPosition, SEEK_SET);
            fwrite($signingTableFile, '#'.$this->_getSigningTableEntryRecord());
            flock($signingTableFile, LOCK_UN);
        } else {
            
        }
        fclose($signingTableFile);
    }

    //Signing tablle entry format *@example.com mail._domainkey.example.com
    private function _getSigningTableEntryRecord() {
        return "*@".$this->domain." ".$this->selector."._domainkey.".$this->domain;
    }

    /**
     *  _createDKIMKeyFolder - create key folder if none exists 
     *  a folder inside /opt/opendkim/keys/ is created with the same name as that of $this->domain
     *  /opt/opendkim/keys/google.com
     *  Private key and DKIM TXT record is generated if none exists.
     */
    private function _createDKIMKeyFolder() {

        if(file_exists($this->_getKeyFolderPath())) {
            //if folder exists make see if file is present
            if(file_exists($this->_getKeyFolderPath()."//".$this->selector.".txt") && file_exists($this->_getKeyFolderPath()."//".$this->selector.".private")) {
                //if keyfile and dkim exists.
                //do nothing.
            } else {
                echo $this->_generateDKIMKeys();
            }

        } else {
            //create folder
            if(mkdir($this->_getKeyFolderPath())) {
                //directory created.
                echo "Directory Created";
                echo $this->_generateDKIMKeys();
            } else {
                //stop
                die();
            }
        }
    }

    private function _generateDKIMKeys() {
        return shell_exec("cd ".$this->_getKeyFolderPath()."//".$this->domain." && opendkim-keygen -s ".$this->selector." -d ".$this->domain);
    }

    private function _getKeyFolderPath() {
        return self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_KEY_DIRECTORY."//".$this->domain;
    }

    public function removeDKIM() {
        //delete keys
        $output = shell_exec("rm -rf ".$this->_getKeyFolderPath()."//".$this->domain);
        //remove entries from KeyTable and SigningTable.
        $this->_removeKeyTablEntry();
        $this->_removeSigningTableEntry();
        
    }

    private function _removeKeyTablEntry() {
        $keyTableFile = fopen(self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_KEY_TABLE, "c+");
        // print_r(stream_get_meta_data($keyTableFile));
        while(!feof($keyTableFile)) {
            $line = fgets($keyTableFile);
            $offset = strpos($line, $this->_getKeyTableEntryRecord());
            if($offset !== FALSE) {
                //found the key
                //do nothing if key found.
                break;
            }
        }
        $cursorPosition = ftell($keyTableFile);
        //move cursor position to starrt of line
        $cursorPosition = $cursorPosition - strlen($line);
        fseek($keyTableFile, $cursorPosition, SEEK_SET);
        if($offset === FALSE) {
            // do nothing
            echo "Non Existent\n";
        } else {

            //get a lock on file before editing
            $lineLength = strlen($line);
            $line = preg_replace("/./", " ", $line);
            //fwrite and flock are used since this file can be accessed by multiple processes at once
            //updation by other process should not result in our changes being lost so we get a exclusive write to it.
            flock($keyTableFile, LOCK_EX);
            fwrite($keyTableFile, $line, $lineLength);
            flock($keyTableFile, LOCK_UN);
            
        }
        fclose($keyTableFile);
    }

    private function _removeSigningTableEntry() {
        $signingTableFile = fopen(self::$OPENDKIM_BASE_DIRECTORY.self::$OPENDKIM_SIGNING_TABLE, "c+");
        // print_r(stream_get_meta_data($signingTableFile));
        while(!feof($signingTableFile)) {
            $line = fgets($signingTableFile);
            $offset = strpos($line, $this->_getSigningTableEntryRecord());
            if($offset !== FALSE) {
                //found the key
                //do nothing if key found.
                break;
            }
        }
        $cursorPosition = ftell($signingTableFile);
        //move cursor position to starrt of line
        $cursorPosition = $cursorPosition - strlen($line);
        fseek($signingTableFile, $cursorPosition, SEEK_SET);
        if($offset === FALSE) {
            // do nothing
            echo "Non Existent\n";
        } else {
            //get a lock on file before editing
            $lineLength = strlen($line);
            $line = preg_replace("/./", " ", $line);
            //fwrite and flock are used since this file can be accessed by multiple processes at once
            //updation by other process should not result in our changes being lost so we get a exclusive write to it.
            flock($signingTableFile, LOCK_EX);
            fwrite($signingTableFile, $line, $lineLength);
            flock($signingTableFile, LOCK_UN);
            
        }
        fclose($signingTableFile);
    }
}