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File Content: `SMTP.php`

<?php

/**
 * PHPMailer RFC821 SMTP email transport class.
 * PHP Version 5.5.
 *
 * @see       https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
 *
 * @author    Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
 * @author    Jim Jagielski (jimjag) <jimjag@gmail.com>
 * @author    Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
 * @author    Brent R. Matzelle (original founder)
 * @copyright 2012 - 2020 Marcus Bointon
 * @copyright 2010 - 2012 Jim Jagielski
 * @copyright 2004 - 2009 Andy Prevost
 * @license   https://www.gnu.org/licenses/old-licenses/lgpl-2.1.html GNU Lesser General Public License
 * @note      This program is distributed in the hope that it will be useful - WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 */

namespace PHPMailer\PHPMailer;

/**
 * PHPMailer RFC821 SMTP email transport class.
 * Implements RFC 821 SMTP commands and provides some utility methods for sending mail to an SMTP server.
 *
 * @author Chris Ryan
 * @author Marcus Bointon <phpmailer@synchromedia.co.uk>
 */
class SMTP
{
    /**
     * The PHPMailer SMTP version number.
     *
     * @var string
     */
    const VERSION = '7.0.0';

    /**
     * SMTP line break constant.
     *
     * @var string
     */
    const LE = "\r\n";

    /**
     * The SMTP port to use if one is not specified.
     *
     * @var int
     */
    const DEFAULT_PORT = 25;

    /**
     * The SMTPs port to use if one is not specified.
     *
     * @var int
     */
    const DEFAULT_SECURE_PORT = 465;

    /**
     * The maximum line length allowed by RFC 5321 section 4.5.3.1.6,
     * *excluding* a trailing CRLF break.
     *
     * @see https://www.rfc-editor.org/rfc/rfc5321#section-4.5.3.1.6
     *
     * @var int
     */
    const MAX_LINE_LENGTH = 998;

    /**
     * The maximum line length allowed for replies in RFC 5321 section 4.5.3.1.5,
     * *including* a trailing CRLF line break.
     *
     * @see https://www.rfc-editor.org/rfc/rfc5321#section-4.5.3.1.5
     *
     * @var int
     */
    const MAX_REPLY_LENGTH = 512;

    /**
     * Debug level for no output.
     *
     * @var int
     */
    const DEBUG_OFF = 0;

    /**
     * Debug level to show client -> server messages.
     *
     * @var int
     */
    const DEBUG_CLIENT = 1;

    /**
     * Debug level to show client -> server and server -> client messages.
     *
     * @var int
     */
    const DEBUG_SERVER = 2;

    /**
     * Debug level to show connection status, client -> server and server -> client messages.
     *
     * @var int
     */
    const DEBUG_CONNECTION = 3;

    /**
     * Debug level to show all messages.
     *
     * @var int
     */
    const DEBUG_LOWLEVEL = 4;

    /**
     * Debug output level.
     * Options:
     * * self::DEBUG_OFF (`0`) No debug output, default
     * * self::DEBUG_CLIENT (`1`) Client commands
     * * self::DEBUG_SERVER (`2`) Client commands and server responses
     * * self::DEBUG_CONNECTION (`3`) As DEBUG_SERVER plus connection status
     * * self::DEBUG_LOWLEVEL (`4`) Low-level data output, all messages.
     *
     * @var int
     */
    public $do_debug = self::DEBUG_OFF;

    /**
     * How to handle debug output.
     * Options:
     * * `echo` Output plain-text as-is, appropriate for CLI
     * * `html` Output escaped, line breaks converted to `<br>`, appropriate for browser output
     * * `error_log` Output to error log as configured in php.ini
     * Alternatively, you can provide a callable expecting two params: a message string and the debug level:
     *
     * ```php
     * $smtp->Debugoutput = function($str, $level) {echo "debug level $level; message: $str";};
     * ```
     *
     * Alternatively, you can pass in an instance of a PSR-3 compatible logger, though only `debug`
     * level output is used:
     *
     * ```php
     * $mail->Debugoutput = new myPsr3Logger;
     * ```
     *
     * @var string|callable|\Psr\Log\LoggerInterface
     */
    public $Debugoutput = 'echo';

    /**
     * Whether to use VERP.
     *
     * @see https://en.wikipedia.org/wiki/Variable_envelope_return_path
     * @see https://www.postfix.org/VERP_README.html Info on VERP
     *
     * @var bool
     */
    public $do_verp = false;

    /**
     * Whether to use SMTPUTF8.
     *
     * @see https://www.rfc-editor.org/rfc/rfc6531
     *
     * @var bool
     */
    public $do_smtputf8 = false;

    /**
     * The timeout value for connection, in seconds.
     * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2.
     * This needs to be quite high to function correctly with hosts using greetdelay as an anti-spam measure.
     *
     * @see https://www.rfc-editor.org/rfc/rfc2821#section-4.5.3.2
     *
     * @var int
     */
    public $Timeout = 300;

    /**
     * How long to wait for commands to complete, in seconds.
     * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2.
     *
     * @var int
     */
    public $Timelimit = 300;

    /**
     * Patterns to extract an SMTP transaction id from reply to a DATA command.
     * The first capture group in each regex will be used as the ID.
     * MS ESMTP returns the message ID, which may not be correct for internal tracking.
     *
     * @var string[]
     */
    protected $smtp_transaction_id_patterns = [
        'exim' => '/[\d]{3} OK id=(.*)/',
        'sendmail' => '/[\d]{3} 2\.0\.0 (.*) Message/',
        'postfix' => '/[\d]{3} 2\.0\.0 Ok: queued as (.*)/',
        'Microsoft_ESMTP' => '/[0-9]{3} 2\.[\d]\.0 (.*)@(?:.*) Queued mail for delivery/',
        'Amazon_SES' => '/[\d]{3} Ok (.*)/',
        'SendGrid' => '/[\d]{3} Ok: queued as (.*)/',
        'CampaignMonitor' => '/[\d]{3} 2\.0\.0 OK:([a-zA-Z\d]{48})/',
        'Haraka' => '/[\d]{3} Message Queued \((.*)\)/',
        'ZoneMTA' => '/[\d]{3} Message queued as (.*)/',
        'Mailjet' => '/[\d]{3} OK queued as (.*)/',
        'Gsmtp' => '/[\d]{3} 2\.0\.0 OK (.*) - gsmtp/',
    ];

    /**
     * Allowed SMTP XCLIENT attributes.
     * Must be allowed by the SMTP server. EHLO response is not checked.
     *
     * @see https://www.postfix.org/XCLIENT_README.html
     *
     * @var array
     */
    public static $xclient_allowed_attributes = [
        'NAME', 'ADDR', 'PORT', 'PROTO', 'HELO', 'LOGIN', 'DESTADDR', 'DESTPORT'
    ];

    /**
     * The last transaction ID issued in response to a DATA command,
     * if one was detected.
     *
     * @var string|bool|null
     */
    protected $last_smtp_transaction_id;

    /**
     * The socket for the server connection.
     *
     * @var ?resource
     */
    protected $smtp_conn;

    /**
     * Error information, if any, for the last SMTP command.
     *
     * @var array
     */
    protected $error = [
        'error' => '',
        'detail' => '',
        'smtp_code' => '',
        'smtp_code_ex' => '',
    ];

    /**
     * The reply the server sent to us for HELO.
     * If null, no HELO string has yet been received.
     *
     * @var string|null
     */
    protected $helo_rply;

    /**
     * The set of SMTP extensions sent in reply to EHLO command.
     * Indexes of the array are extension names.
     * Value at index 'HELO' or 'EHLO' (according to command that was sent)
     * represents the server name. In case of HELO it is the only element of the array.
     * Other values can be boolean TRUE or an array containing extension options.
     * If null, no HELO/EHLO string has yet been received.
     *
     * @var array|null
     */
    protected $server_caps;

    /**
     * The most recent reply received from the server.
     *
     * @var string
     */
    protected $last_reply = '';

    /**
     * Output debugging info via a user-selected method.
     *
     * @param string $str   Debug string to output
     * @param int    $level The debug level of this message; see DEBUG_* constants
     *
     * @see SMTP::$Debugoutput
     * @see SMTP::$do_debug
     */
    protected function edebug($str, $level = 0)
    {
        if ($level > $this->do_debug) {
            return;
        }
        //Is this a PSR-3 logger?
        if ($this->Debugoutput instanceof \Psr\Log\LoggerInterface) {
            //Remove trailing line breaks potentially added by calls to SMTP::client_send()
            $this->Debugoutput->debug(rtrim($str, "\r\n"));

            return;
        }
        //Avoid clash with built-in function names
        if (is_callable($this->Debugoutput) && !in_array($this->Debugoutput, ['error_log', 'html', 'echo'])) {
            call_user_func($this->Debugoutput, $str, $level);

            return;
        }
        switch ($this->Debugoutput) {
            case 'error_log':
                //Don't output, just log
                /** @noinspection ForgottenDebugOutputInspection */
                error_log($str);
                break;
            case 'html':
                //Cleans up output a bit for a better looking, HTML-safe output
                echo gmdate('Y-m-d H:i:s'), ' ', htmlentities(
                    preg_replace('/[\r\n]+/', '', $str),
                    ENT_QUOTES,
                    'UTF-8'
                ), "<br>\n";
                break;
            case 'echo':
            default:
                //Normalize line breaks
                $str = preg_replace('/\r\n|\r/m', "\n", $str);
                echo gmdate('Y-m-d H:i:s'),
                "\t",
                    //Trim trailing space
                trim(
                    //Indent for readability, except for trailing break
                    str_replace(
                        "\n",
                        "\n                   \t                  ",
                        trim($str)
                    )
                ),
                "\n";
        }
    }

    /**
     * Connect to an SMTP server.
     *
     * @param string $host    SMTP server IP or host name
     * @param int    $port    The port number to connect to
     * @param int    $timeout How long to wait for the connection to open
     * @param array  $options An array of options for stream_context_create()
     *
     * @return bool
     */
    public function connect($host, $port = null, $timeout = 30, $options = [])
    {
        //Clear errors to avoid confusion
        $this->setError('');
        //Make sure we are __not__ connected
        if ($this->connected()) {
            //Already connected, generate error
            $this->setError('Already connected to a server');

            return false;
        }
        if (empty($port)) {
            $port = self::DEFAULT_PORT;
        }
        //Connect to the SMTP server
        $this->edebug(
            "Connection: opening to $host:$port, timeout=$timeout, options=" .
            (count($options) > 0 ? var_export($options, true) : 'array()'),
            self::DEBUG_CONNECTION
        );

        $this->smtp_conn = $this->getSMTPConnection($host, $port, $timeout, $options);

        if ($this->smtp_conn === false) {
            //Error info already set inside `getSMTPConnection()`
            return false;
        }

        $this->edebug('Connection: opened', self::DEBUG_CONNECTION);

        //Get any announcement
        $this->last_reply = $this->get_lines();
        $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);
        $responseCode = (int)substr($this->last_reply, 0, 3);
        if ($responseCode === 220) {
            return true;
        }
        //Anything other than a 220 response means something went wrong
        //RFC 5321 says the server will wait for us to send a QUIT in response to a 554 error
        //https://www.rfc-editor.org/rfc/rfc5321#section-3.1
        if ($responseCode === 554) {
            $this->quit();
        }
        //This will handle 421 responses which may not wait for a QUIT (e.g. if the server is being shut down)
        $this->edebug('Connection: closing due to error', self::DEBUG_CONNECTION);
        $this->close();
        return false;
    }

    /**
     * Create connection to the SMTP server.
     *
     * @param string $host    SMTP server IP or host name
     * @param int    $port    The port number to connect to
     * @param int    $timeout How long to wait for the connection to open
     * @param array  $options An array of options for stream_context_create()
     *
     * @return false|resource
     */
    protected function getSMTPConnection($host, $port = null, $timeout = 30, $options = [])
    {
        static $streamok;
        //This is enabled by default since 5.0.0 but some providers disable it
        //Check this once and cache the result
        if (null === $streamok) {
            $streamok = function_exists('stream_socket_client');
        }

        $errno = 0;
        $errstr = '';
        if ($streamok) {
            $socket_context = stream_context_create($options);
            set_error_handler(function () {
                call_user_func_array([$this, 'errorHandler'], func_get_args());
            });
            $connection = stream_socket_client(
                $host . ':' . $port,
                $errno,
                $errstr,
                $timeout,
                STREAM_CLIENT_CONNECT,
                $socket_context
            );
        } else {
            //Fall back to fsockopen which should work in more places, but is missing some features
            $this->edebug(
                'Connection: stream_socket_client not available, falling back to fsockopen',
                self::DEBUG_CONNECTION
            );
            set_error_handler(function () {
                call_user_func_array([$this, 'errorHandler'], func_get_args());
            });
            $connection = fsockopen(
                $host,
                $port,
                $errno,
                $errstr,
                $timeout
            );
        }
        restore_error_handler();

        //Verify we connected properly
        if (!is_resource($connection)) {
            $this->setError(
                'Failed to connect to server',
                '',
                (string) $errno,
                $errstr
            );
            $this->edebug(
                'SMTP ERROR: ' . $this->error['error']
                . ": $errstr ($errno)",
                self::DEBUG_CLIENT
            );

            return false;
        }

        //SMTP server can take longer to respond, give longer timeout for first read
        //Windows does not have support for this timeout function
        if (strpos(PHP_OS, 'WIN') !== 0) {
            $max = (int)ini_get('max_execution_time');
            //Don't bother if unlimited, or if set_time_limit is disabled
            if (0 !== $max && $timeout > $max && strpos(ini_get('disable_functions'), 'set_time_limit') === false) {
                @set_time_limit($timeout);
            }
            stream_set_timeout($connection, $timeout, 0);
        }

        return $connection;
    }

    /**
     * Initiate a TLS (encrypted) session.
     *
     * @return bool
     */
    public function startTLS()
    {
        if (!$this->sendCommand('STARTTLS', 'STARTTLS', 220)) {
            return false;
        }

        //Allow the best TLS version(s) we can
        $crypto_method = STREAM_CRYPTO_METHOD_TLS_CLIENT;

        //PHP 5.6.7 dropped inclusion of TLS 1.1 and 1.2 in STREAM_CRYPTO_METHOD_TLS_CLIENT
        //so add them back in manually if we can
        if (defined('STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT')) {
            $crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT;
            $crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT;
        }

        //Begin encrypted connection
            set_error_handler(function () {
                call_user_func_array([$this, 'errorHandler'], func_get_args());
            });
        $crypto_ok = stream_socket_enable_crypto(
            $this->smtp_conn,
            true,
            $crypto_method
        );
        restore_error_handler();

        return (bool) $crypto_ok;
    }

    /**
     * Perform SMTP authentication.
     * Must be run after hello().
     *
     * @see    hello()
     *
     * @param string $username The user name
     * @param string $password The password
     * @param string $authtype The auth type (CRAM-MD5, PLAIN, LOGIN, XOAUTH2)
     * @param OAuthTokenProvider $OAuth An optional OAuthTokenProvider instance for XOAUTH2 authentication
     *
     * @return bool True if successfully authenticated
     */
    public function authenticate(
        $username,
        $password,
        $authtype = null,
        $OAuth = null
    ) {
        if (!$this->server_caps) {
            $this->setError('Authentication is not allowed before HELO/EHLO');

            return false;
        }

        if (array_key_exists('EHLO', $this->server_caps)) {
            //SMTP extensions are available; try to find a proper authentication method
            if (!array_key_exists('AUTH', $this->server_caps)) {
                $this->setError('Authentication is not allowed at this stage');
                //'at this stage' means that auth may be allowed after the stage changes
                //e.g. after STARTTLS

                return false;
            }

            $this->edebug('Auth method requested: ' . ($authtype ?: 'UNSPECIFIED'), self::DEBUG_LOWLEVEL);
            $this->edebug(
                'Auth methods available on the server: ' . implode(',', $this->server_caps['AUTH']),
                self::DEBUG_LOWLEVEL
            );

            //If we have requested a specific auth type, check the server supports it before trying others
            if (null !== $authtype && !in_array($authtype, $this->server_caps['AUTH'], true)) {
                $this->edebug('Requested auth method not available: ' . $authtype, self::DEBUG_LOWLEVEL);
                $authtype = null;
            }

            if (empty($authtype)) {
                //If no auth mechanism is specified, attempt to use these, in this order
                //Try CRAM-MD5 first as it's more secure than the others
                foreach (['CRAM-MD5', 'LOGIN', 'PLAIN', 'XOAUTH2'] as $method) {
                    if (in_array($method, $this->server_caps['AUTH'], true)) {
                        $authtype = $method;
                        break;
                    }
                }
                if (empty($authtype)) {
                    $this->setError('No supported authentication methods found');

                    return false;
                }
                $this->edebug('Auth method selected: ' . $authtype, self::DEBUG_LOWLEVEL);
            }

            if (!in_array($authtype, $this->server_caps['AUTH'], true)) {
                $this->setError("The requested authentication method \"$authtype\" is not supported by the server");

                return false;
            }
        } elseif (empty($authtype)) {
            $authtype = 'LOGIN';
        }
        switch ($authtype) {
            case 'PLAIN':
                //Start authentication
                if (!$this->sendCommand('AUTH', 'AUTH PLAIN', 334)) {
                    return false;
                }
                //Send encoded username and password
                if (
                    //Format from https://www.rfc-editor.org/rfc/rfc4616#section-2
                    //We skip the first field (it's forgery), so the string starts with a null byte
                    !$this->sendCommand(
                        'User & Password',
                        base64_encode("\0" . $username . "\0" . $password),
                        235
                    )
                ) {
                    return false;
                }
                break;
            case 'LOGIN':
                //Start authentication
                if (!$this->sendCommand('AUTH', 'AUTH LOGIN', 334)) {
                    return false;
                }
                if (!$this->sendCommand('Username', base64_encode($username), 334)) {
                    return false;
                }
                if (!$this->sendCommand('Password', base64_encode($password), 235)) {
                    return false;
                }
                break;
            case 'CRAM-MD5':
                //Start authentication
                if (!$this->sendCommand('AUTH CRAM-MD5', 'AUTH CRAM-MD5', 334)) {
                    return false;
                }
                //Get the challenge
                $challenge = base64_decode(substr($this->last_reply, 4));

                //Build the response
                $response = $username . ' ' . $this->hmac($challenge, $password);

                //send encoded credentials
                return $this->sendCommand('Username', base64_encode($response), 235);
            case 'XOAUTH2':
                //The OAuth instance must be set up prior to requesting auth.
                if (null === $OAuth) {
                    return false;
                }
                $oauth = $OAuth->getOauth64();
                /*
                 * An SMTP command line can have a maximum length of 512 bytes, including the command name,
                 * so the base64-encoded OAUTH token has a maximum length of:
                 * 512 - 13 (AUTH XOAUTH2) - 2 (CRLF) = 497 bytes
                 * If the token is longer than that, the command and the token must be sent separately as described in
                 * https://www.rfc-editor.org/rfc/rfc4954#section-4
                 */
                if ($oauth === '') {
                    //Sending an empty auth token is legitimate, but it must be encoded as '='
                    //to indicate it's not a 2-part command
                    if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 =', 235)) {
                        return false;
                    }
                } elseif (strlen($oauth) <= 497) {
                    //Authenticate using a token in the initial-response part
                    if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 ' . $oauth, 235)) {
                        return false;
                    }
                } else {
                    //The token is too long, so we need to send it in two parts.
                    //Send the auth command without a token and expect a 334
                    if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2', 334)) {
                        return false;
                    }
                    //Send the token
                    if (!$this->sendCommand('OAuth TOKEN', $oauth, [235, 334])) {
                        return false;
                    }
                    //If the server answers with 334, send an empty line and wait for a 235
                    if (
                        substr($this->last_reply, 0, 3) === '334'
                        && $this->sendCommand('AUTH End', '', 235)
                    ) {
                        return false;
                    }
                }
                break;
            default:
                $this->setError("Authentication method \"$authtype\" is not supported");

                return false;
        }

        return true;
    }

    /**
     * Calculate an MD5 HMAC hash.
     * Works like hash_hmac('md5', $data, $key)
     * in case that function is not available.
     *
     * @param string $data The data to hash
     * @param string $key  The key to hash with
     *
     * @return string
     */
    protected function hmac($data, $key)
    {
        if (function_exists('hash_hmac')) {
            return hash_hmac('md5', $data, $key);
        }

        //The following borrowed from
        //https://www.php.net/manual/en/function.mhash.php#27225

        //RFC 2104 HMAC implementation for php.
        //Creates an md5 HMAC.
        //Eliminates the need to install mhash to compute a HMAC
        //by Lance Rushing

        $bytelen = 64; //byte length for md5
        if (strlen($key) > $bytelen) {
            $key = pack('H*', md5($key));
        }
        $key = str_pad($key, $bytelen, chr(0x00));
        $ipad = str_pad('', $bytelen, chr(0x36));
        $opad = str_pad('', $bytelen, chr(0x5c));
        $k_ipad = $key ^ $ipad;
        $k_opad = $key ^ $opad;

        return md5($k_opad . pack('H*', md5($k_ipad . $data)));
    }

    /**
     * Check connection state.
     *
     * @return bool True if connected
     */
    public function connected()
    {
        if (is_resource($this->smtp_conn)) {
            $sock_status = stream_get_meta_data($this->smtp_conn);
            if ($sock_status['eof']) {
                //The socket is valid but we are not connected
                $this->edebug(
                    'SMTP NOTICE: EOF caught while checking if connected',
                    self::DEBUG_CLIENT
                );
                $this->close();

                return false;
            }

            return true; //everything looks good
        }

        return false;
    }

    /**
     * Close the socket and clean up the state of the class.
     * Don't use this function without first trying to use QUIT.
     *
     * @see quit()
     */
    public function close()
    {
        $this->server_caps = null;
        $this->helo_rply = null;
        if (is_resource($this->smtp_conn)) {
            //Close the connection and cleanup
            fclose($this->smtp_conn);
            $this->smtp_conn = null; //Makes for cleaner serialization
            $this->edebug('Connection: closed', self::DEBUG_CONNECTION);
        }
    }

    /**
     * Send an SMTP DATA command.
     * Issues a data command and sends the msg_data to the server,
     * finalizing the mail transaction. $msg_data is the message
     * that is to be sent with the headers. Each header needs to be
     * on a single line followed by a <CRLF> with the message headers
     * and the message body being separated by an additional <CRLF>.
     * Implements RFC 821: DATA <CRLF>.
     *
     * @param string $msg_data Message data to send
     *
     * @return bool
     */
    public function data($msg_data)
    {
        //This will use the standard timelimit
        if (!$this->sendCommand('DATA', 'DATA', 354)) {
            return false;
        }

        /* The server is ready to accept data!
         * According to rfc821 we should not send more than 1000 characters on a single line (including the LE)
         * so we will break the data up into lines by \r and/or \n then if needed we will break each of those into
         * smaller lines to fit within the limit.
         * We will also look for lines that start with a '.' and prepend an additional '.'.
         * NOTE: this does not count towards line-length limit.
         */

        //Normalize line breaks before exploding
        $lines = explode("\n", str_replace(["\r\n", "\r"], "\n", $msg_data));

        /* To distinguish between a complete RFC822 message and a plain message body, we check if the first field
         * of the first line (':' separated) does not contain a space then it _should_ be a header, and we will
         * process all lines before a blank line as headers.
         */

        $field = substr($lines[0], 0, strpos($lines[0], ':'));
        $in_headers = false;
        if (!empty($field) && strpos($field, ' ') === false) {
            $in_headers = true;
        }

        foreach ($lines as $line) {
            $lines_out = [];
            if ($in_headers && $line === '') {
                $in_headers = false;
            }
            //Break this line up into several smaller lines if it's too long
            //Micro-optimisation: isset($str[$len]) is faster than (strlen($str) > $len),
            while (isset($line[self::MAX_LINE_LENGTH])) {
                //Working backwards, try to find a space within the last MAX_LINE_LENGTH chars of the line to break on
                //so as to avoid breaking in the middle of a word
                $pos = strrpos(substr($line, 0, self::MAX_LINE_LENGTH), ' ');
                //Deliberately matches both false and 0
                if (!$pos) {
                    //No nice break found, add a hard break
                    $pos = self::MAX_LINE_LENGTH - 1;
                    $lines_out[] = substr($line, 0, $pos);
                    $line = substr($line, $pos);
                } else {
                    //Break at the found point
                    $lines_out[] = substr($line, 0, $pos);
                    //Move along by the amount we dealt with
                    $line = substr($line, $pos + 1);
                }
                //If processing headers add a LWSP-char to the front of new line RFC822 section 3.1.1
                if ($in_headers) {
                    $line = "\t" . $line;
                }
            }
            $lines_out[] = $line;

            //Send the lines to the server
            foreach ($lines_out as $line_out) {
                //Dot-stuffing as per RFC5321 section 4.5.2
                //https://www.rfc-editor.org/rfc/rfc5321#section-4.5.2
                if (!empty($line_out) && $line_out[0] === '.') {
                    $line_out = '.' . $line_out;
                }
                $this->client_send($line_out . static::LE, 'DATA');
            }
        }

        //Message data has been sent, complete the command
        //Increase timelimit for end of DATA command
        $savetimelimit = $this->Timelimit;
        $this->Timelimit *= 2;
        $result = $this->sendCommand('DATA END', '.', 250);
        $this->recordLastTransactionID();
        //Restore timelimit
        $this->Timelimit = $savetimelimit;

        return $result;
    }

    /**
     * Send an SMTP HELO or EHLO command.
     * Used to identify the sending server to the receiving server.
     * This makes sure that client and server are in a known state.
     * Implements RFC 821: HELO <SP> <domain> <CRLF>
     * and RFC 2821 EHLO.
     *
     * @param string $host The host name or IP to connect to
     *
     * @return bool
     */
    public function hello($host = '')
    {
        //Try extended hello first (RFC 2821)
        if ($this->sendHello('EHLO', $host)) {
            return true;
        }

        //Some servers shut down the SMTP service here (RFC 5321)
        if (substr($this->helo_rply, 0, 3) == '421') {
            return false;
        }

        return $this->sendHello('HELO', $host);
    }

    /**
     * Send an SMTP HELO or EHLO command.
     * Low-level implementation used by hello().
     *
     * @param string $hello The HELO string
     * @param string $host  The hostname to say we are
     *
     * @return bool
     *
     * @see hello()
     */
    protected function sendHello($hello, $host)
    {
        $noerror = $this->sendCommand($hello, $hello . ' ' . $host, 250);
        $this->helo_rply = $this->last_reply;
        if ($noerror) {
            $this->parseHelloFields($hello);
        } else {
            $this->server_caps = null;
        }

        return $noerror;
    }

    /**
     * Parse a reply to HELO/EHLO command to discover server extensions.
     * In case of HELO, the only parameter that can be discovered is a server name.
     *
     * @param string $type `HELO` or `EHLO`
     */
    protected function parseHelloFields($type)
    {
        $this->server_caps = [];
        $lines = explode("\n", $this->helo_rply);

        foreach ($lines as $n => $s) {
            //First 4 chars contain response code followed by - or space
            $s = trim(substr($s, 4));
            if (empty($s)) {
                continue;
            }
            $fields = explode(' ', $s);
            if (!empty($fields)) {
                if (!$n) {
                    $name = $type;
                    $fields = $fields[0];
                } else {
                    $name = array_shift($fields);
                    switch ($name) {
                        case 'SIZE':
                            $fields = ($fields ? $fields[0] : 0);
                            break;
                        case 'AUTH':
                            if (!is_array($fields)) {
                                $fields = [];
                            }
                            break;
                        default:
                            $fields = true;
                    }
                }
                $this->server_caps[$name] = $fields;
            }
        }
    }

    /**
     * Send an SMTP MAIL command.
     * Starts a mail transaction from the email address specified in
     * $from. Returns true if successful or false otherwise. If True
     * the mail transaction is started and then one or more recipient
     * commands may be called followed by a data command.
     * Implements RFC 821: MAIL <SP> FROM:<reverse-path> <CRLF> and
     * two extensions, namely XVERP and SMTPUTF8.
     *
     * The server's EHLO response is not checked. If use of either
     * extensions is enabled even though the server does not support
     * that, mail submission will fail.
     *
     * XVERP is documented at https://www.postfix.org/VERP_README.html
     * and SMTPUTF8 is specified in RFC 6531.
     *
     * @param string $from Source address of this message
     *
     * @return bool
     */
    public function mail($from)
    {
        $useVerp = ($this->do_verp ? ' XVERP' : '');
        $useSmtputf8 = ($this->do_smtputf8 ? ' SMTPUTF8' : '');

        return $this->sendCommand(
            'MAIL FROM',
            'MAIL FROM:<' . $from . '>' . $useSmtputf8 . $useVerp,
            250
        );
    }

    /**
     * Send an SMTP QUIT command.
     * Closes the socket if there is no error or the $close_on_error argument is true.
     * Implements from RFC 821: QUIT <CRLF>.
     *
     * @param bool $close_on_error Should the connection close if an error occurs?
     *
     * @return bool
     */
    public function quit($close_on_error = true)
    {
        $noerror = $this->sendCommand('QUIT', 'QUIT', 221);
        $err = $this->error; //Save any error
        if ($noerror || $close_on_error) {
            $this->close();
            $this->error = $err; //Restore any error from the quit command
        }

        return $noerror;
    }

    /**
     * Send an SMTP RCPT command.
     * Sets the TO argument to $toaddr.
     * Returns true if the recipient was accepted false if it was rejected.
     * Implements from RFC 821: RCPT <SP> TO:<forward-path> <CRLF>.
     *
     * @param string $address The address the message is being sent to
     * @param string $dsn     Comma separated list of DSN notifications. NEVER, SUCCESS, FAILURE
     *                        or DELAY. If you specify NEVER all other notifications are ignored.
     *
     * @return bool
     */
    public function recipient($address, $dsn = '')
    {
        if (empty($dsn)) {
            $rcpt = 'RCPT TO:<' . $address . '>';
        } else {
            $dsn = strtoupper($dsn);
            $notify = [];

            if (strpos($dsn, 'NEVER') !== false) {
                $notify[] = 'NEVER';
            } else {
                foreach (['SUCCESS', 'FAILURE', 'DELAY'] as $value) {
                    if (strpos($dsn, $value) !== false) {
                        $notify[] = $value;
                    }
                }
            }

            $rcpt = 'RCPT TO:<' . $address . '> NOTIFY=' . implode(',', $notify);
        }

        return $this->sendCommand(
            'RCPT TO',
            $rcpt,
            [250, 251]
        );
    }

    /**
     * Send SMTP XCLIENT command to server and check its return code.
     *
     * @return bool True on success
     */
    public function xclient(array $vars)
    {
        $xclient_options = "";
        foreach ($vars as $key => $value) {
            if (in_array($key, SMTP::$xclient_allowed_attributes)) {
                $xclient_options .= " {$key}={$value}";
            }
        }
        if (!$xclient_options) {
            return true;
        }
        return $this->sendCommand('XCLIENT', 'XCLIENT' . $xclient_options, 250);
    }

    /**
     * Send an SMTP RSET command.
     * Abort any transaction that is currently in progress.
     * Implements RFC 821: RSET <CRLF>.
     *
     * @return bool True on success
     */
    public function reset()
    {
        return $this->sendCommand('RSET', 'RSET', 250);
    }

    /**
     * Send a command to an SMTP server and check its return code.
     *
     * @param string    $command       The command name - not sent to the server
     * @param string    $commandstring The actual command to send
     * @param int|array $expect        One or more expected integer success codes
     *
     * @return bool True on success
     */
    protected function sendCommand($command, $commandstring, $expect)
    {
        if (!$this->connected()) {
            $this->setError("Called $command without being connected");

            return false;
        }
        //Reject line breaks in all commands
        if ((strpos($commandstring, "\n") !== false) || (strpos($commandstring, "\r") !== false)) {
            $this->setError("Command '$command' contained line breaks");

            return false;
        }
        $this->client_send($commandstring . static::LE, $command);

        $this->last_reply = $this->get_lines();
        //Fetch SMTP code and possible error code explanation
        $matches = [];
        if (preg_match('/^([\d]{3})[ -](?:([\d]\\.[\d]\\.[\d]{1,2}) )?/', $this->last_reply, $matches)) {
            $code = (int) $matches[1];
            $code_ex = (count($matches) > 2 ? $matches[2] : null);
            //Cut off error code from each response line
            $detail = preg_replace(
                "/{$code}[ -]" .
                ($code_ex ? str_replace('.', '\\.', $code_ex) . ' ' : '') . '/m',
                '',
                $this->last_reply
            );
        } else {
            //Fall back to simple parsing if regex fails
            $code = (int) substr($this->last_reply, 0, 3);
            $code_ex = null;
            $detail = substr($this->last_reply, 4);
        }

        $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);

        if (!in_array($code, (array) $expect, true)) {
            $this->setError(
                "$command command failed",
                $detail,
                $code,
                $code_ex
            );
            $this->edebug(
                'SMTP ERROR: ' . $this->error['error'] . ': ' . $this->last_reply,
                self::DEBUG_CLIENT
            );

            return false;
        }

        //Don't clear the error store when using keepalive
        if ($command !== 'RSET') {
            $this->setError('');
        }

        return true;
    }

    /**
     * Send an SMTP SAML command.
     * Starts a mail transaction from the email address specified in $from.
     * Returns true if successful or false otherwise. If True
     * the mail transaction is started and then one or more recipient
     * commands may be called followed by a data command. This command
     * will send the message to the users terminal if they are logged
     * in and send them an email.
     * Implements RFC 821: SAML <SP> FROM:<reverse-path> <CRLF>.
     *
     * @param string $from The address the message is from
     *
     * @return bool
     */
    public function sendAndMail($from)
    {
        return $this->sendCommand('SAML', "SAML FROM:$from", 250);
    }

    /**
     * Send an SMTP VRFY command.
     *
     * @param string $name The name to verify
     *
     * @return bool
     */
    public function verify($name)
    {
        return $this->sendCommand('VRFY', "VRFY $name", [250, 251]);
    }

    /**
     * Send an SMTP NOOP command.
     * Used to keep keep-alives alive, doesn't actually do anything.
     *
     * @return bool
     */
    public function noop()
    {
        return $this->sendCommand('NOOP', 'NOOP', 250);
    }

    /**
     * Send an SMTP TURN command.
     * This is an optional command for SMTP that this class does not support.
     * This method is here to make the RFC821 Definition complete for this class
     * and _may_ be implemented in future.
     * Implements from RFC 821: TURN <CRLF>.
     *
     * @return bool
     */
    public function turn()
    {
        $this->setError('The SMTP TURN command is not implemented');
        $this->edebug('SMTP NOTICE: ' . $this->error['error'], self::DEBUG_CLIENT);

        return false;
    }

    /**
     * Send raw data to the server.
     *
     * @param string $data    The data to send
     * @param string $command Optionally, the command this is part of, used only for controlling debug output
     *
     * @return int|bool The number of bytes sent to the server or false on error
     */
    public function client_send($data, $command = '')
    {
        //If SMTP transcripts are left enabled, or debug output is posted online
        //it can leak credentials, so hide credentials in all but lowest level
        if (
            self::DEBUG_LOWLEVEL > $this->do_debug &&
            in_array($command, ['User & Password', 'Username', 'Password'], true)
        ) {
            $this->edebug('CLIENT -> SERVER: [credentials hidden]', self::DEBUG_CLIENT);
        } else {
            $this->edebug('CLIENT -> SERVER: ' . $data, self::DEBUG_CLIENT);
        }
        set_error_handler(function () {
            call_user_func_array([$this, 'errorHandler'], func_get_args());
        });
        $result = fwrite($this->smtp_conn, $data);
        restore_error_handler();

        return $result;
    }

    /**
     * Get the latest error.
     *
     * @return array
     */
    public function getError()
    {
        return $this->error;
    }

    /**
     * Get SMTP extensions available on the server.
     *
     * @return array|null
     */
    public function getServerExtList()
    {
        return $this->server_caps;
    }

    /**
     * Get metadata about the SMTP server from its HELO/EHLO response.
     * The method works in three ways, dependent on argument value and current state:
     *   1. HELO/EHLO has not been sent - returns null and populates $this->error.
     *   2. HELO has been sent -
     *     $name == 'HELO': returns server name
     *     $name == 'EHLO': returns boolean false
     *     $name == any other string: returns null and populates $this->error
     *   3. EHLO has been sent -
     *     $name == 'HELO'|'EHLO': returns the server name
     *     $name == any other string: if extension $name exists, returns True
     *       or its options (e.g. AUTH mechanisms supported). Otherwise returns False.
     *
     * @param string $name Name of SMTP extension or 'HELO'|'EHLO'
     *
     * @return string|bool|null
     */
    public function getServerExt($name)
    {
        if (!$this->server_caps) {
            $this->setError('No HELO/EHLO was sent');

            return null;
        }

        if (!array_key_exists($name, $this->server_caps)) {
            if ('HELO' === $name) {
                return $this->server_caps['EHLO'];
            }
            if ('EHLO' === $name || array_key_exists('EHLO', $this->server_caps)) {
                return false;
            }
            $this->setError('HELO handshake was used; No information about server extensions available');

            return null;
        }

        return $this->server_caps[$name];
    }

    /**
     * Get the last reply from the server.
     *
     * @return string
     */
    public function getLastReply()
    {
        return $this->last_reply;
    }

    /**
     * Read the SMTP server's response.
     * Either before eof or socket timeout occurs on the operation.
     * With SMTP we can tell if we have more lines to read if the
     * 4th character is '-' symbol. If it is a space then we don't
     * need to read anything else.
     *
     * @return string
     */
    protected function get_lines()
    {
        //If the connection is bad, give up straight away
        if (!is_resource($this->smtp_conn)) {
            return '';
        }
        $data = '';
        $endtime = 0;
        stream_set_timeout($this->smtp_conn, $this->Timeout);
        if ($this->Timelimit > 0) {
            $endtime = time() + $this->Timelimit;
        }
        $selR = [$this->smtp_conn];
        $selW = null;
        while (is_resource($this->smtp_conn) && !feof($this->smtp_conn)) {
            //Must pass vars in here as params are by reference
            //solution for signals inspired by https://github.com/symfony/symfony/pull/6540
            set_error_handler(function () {
                call_user_func_array([$this, 'errorHandler'], func_get_args());
            });
            $n = stream_select($selR, $selW, $selW, $this->Timelimit);
            restore_error_handler();

            if ($n === false) {
                $message = $this->getError()['detail'];

                $this->edebug(
                    'SMTP -> get_lines(): select failed (' . $message . ')',
                    self::DEBUG_LOWLEVEL
                );

                //stream_select returns false when the `select` system call is interrupted
                //by an incoming signal, try the select again
                if (
                    stripos($message, 'interrupted system call') !== false ||
                    (
                        // on applications with a different locale than english, the message above is not found because
                        // it's translated. So we also check for the SOCKET_EINTR constant which is defined under
                        // Windows and UNIX-like platforms (if available on the platform).
                        defined('SOCKET_EINTR') &&
                        stripos($message, 'stream_select(): Unable to select [' . SOCKET_EINTR . ']') !== false
                    )
                ) {
                    $this->edebug(
                        'SMTP -> get_lines(): retrying stream_select',
                        self::DEBUG_LOWLEVEL
                    );
                    $this->setError('');
                    continue;
                }

                break;
            }

            if (!$n) {
                $this->edebug(
                    'SMTP -> get_lines(): select timed-out in (' . $this->Timelimit . ' sec)',
                    self::DEBUG_LOWLEVEL
                );
                break;
            }

            //Deliberate noise suppression - errors are handled afterwards
            $str = @fgets($this->smtp_conn, self::MAX_REPLY_LENGTH);
            $this->edebug('SMTP INBOUND: "' . trim($str) . '"', self::DEBUG_LOWLEVEL);
            $data .= $str;
            //If response is only 3 chars (not valid, but RFC5321 S4.2 says it must be handled),
            //or 4th character is a space or a line break char, we are done reading, break the loop.
            //String array access is a significant micro-optimisation over strlen
            if (!isset($str[3]) || $str[3] === ' ' || $str[3] === "\r" || $str[3] === "\n") {
                break;
            }
            //Timed-out? Log and break
            $info = stream_get_meta_data($this->smtp_conn);
            if ($info['timed_out']) {
                $this->edebug(
                    'SMTP -> get_lines(): stream timed-out (' . $this->Timeout . ' sec)',
                    self::DEBUG_LOWLEVEL
                );
                break;
            }
            //Now check if reads took too long
            if ($endtime && time() > $endtime) {
                $this->edebug(
                    'SMTP -> get_lines(): timelimit reached (' .
                    $this->Timelimit . ' sec)',
                    self::DEBUG_LOWLEVEL
                );
                break;
            }
        }

        return $data;
    }

    /**
     * Enable or disable VERP address generation.
     *
     * @param bool $enabled
     */
    public function setVerp($enabled = false)
    {
        $this->do_verp = $enabled;
    }

    /**
     * Get VERP address generation mode.
     *
     * @return bool
     */
    public function getVerp()
    {
        return $this->do_verp;
    }

    /**
     * Enable or disable use of SMTPUTF8.
     *
     * @param bool $enabled
     */
    public function setSMTPUTF8($enabled = false)
    {
        $this->do_smtputf8 = $enabled;
    }

    /**
     * Get SMTPUTF8 use.
     *
     * @return bool
     */
    public function getSMTPUTF8()
    {
        return $this->do_smtputf8;
    }

    /**
     * Set error messages and codes.
     *
     * @param string $message      The error message
     * @param string $detail       Further detail on the error
     * @param string $smtp_code    An associated SMTP error code
     * @param string $smtp_code_ex Extended SMTP code
     */
    protected function setError($message, $detail = '', $smtp_code = '', $smtp_code_ex = '')
    {
        $this->error = [
            'error' => $message,
            'detail' => $detail,
            'smtp_code' => $smtp_code,
            'smtp_code_ex' => $smtp_code_ex,
        ];
    }

    /**
     * Set debug output method.
     *
     * @param string|callable $method The name of the mechanism to use for debugging output, or a callable to handle it
     */
    public function setDebugOutput($method = 'echo')
    {
        $this->Debugoutput = $method;
    }

    /**
     * Get debug output method.
     *
     * @return string
     */
    public function getDebugOutput()
    {
        return $this->Debugoutput;
    }

    /**
     * Set debug output level.
     *
     * @param int $level
     */
    public function setDebugLevel($level = 0)
    {
        $this->do_debug = $level;
    }

    /**
     * Get debug output level.
     *
     * @return int
     */
    public function getDebugLevel()
    {
        return $this->do_debug;
    }

    /**
     * Set SMTP timeout.
     *
     * @param int $timeout The timeout duration in seconds
     */
    public function setTimeout($timeout = 0)
    {
        $this->Timeout = $timeout;
    }

    /**
     * Get SMTP timeout.
     *
     * @return int
     */
    public function getTimeout()
    {
        return $this->Timeout;
    }

    /**
     * Reports an error number and string.
     *
     * @param int    $errno   The error number returned by PHP
     * @param string $errmsg  The error message returned by PHP
     * @param string $errfile The file the error occurred in
     * @param int    $errline The line number the error occurred on
     */
    protected function errorHandler($errno, $errmsg, $errfile = '', $errline = 0)
    {
        $notice = 'Connection failed.';
        $this->setError(
            $notice,
            $errmsg,
            (string) $errno
        );
        $this->edebug(
            "$notice Error #$errno: $errmsg [$errfile line $errline]",
            self::DEBUG_CONNECTION
        );
    }

    /**
     * Extract and return the ID of the last SMTP transaction based on
     * a list of patterns provided in SMTP::$smtp_transaction_id_patterns.
     * Relies on the host providing the ID in response to a DATA command.
     * If no reply has been received yet, it will return null.
     * If no pattern was matched, it will return false.
     *
     * @return bool|string|null
     */
    protected function recordLastTransactionID()
    {
        $reply = $this->getLastReply();

        if (empty($reply)) {
            $this->last_smtp_transaction_id = null;
        } else {
            $this->last_smtp_transaction_id = false;
            foreach ($this->smtp_transaction_id_patterns as $smtp_transaction_id_pattern) {
                $matches = [];
                if (preg_match($smtp_transaction_id_pattern, $reply, $matches)) {
                    $this->last_smtp_transaction_id = trim($matches[1]);
                    break;
                }
            }
        }

        return $this->last_smtp_transaction_id;
    }

    /**
     * Get the queue/transaction ID of the last SMTP transaction
     * If no reply has been received yet, it will return null.
     * If no pattern was matched, it will return false.
     *
     * @return bool|string|null
     *
     * @see recordLastTransactionID()
     */
    public function getLastTransactionID()
    {
        return $this->last_smtp_transaction_id;
    }
}
Name	Size	Permission
DSNConfigurator.php	6883 bytes	0644
Exception.php	1256 bytes	0644
OAuth.php	3791 bytes	0644
OAuthTokenProvider.php	1538 bytes	0644
PHPMailer.php	191033 bytes	0644
POP3.php	12351 bytes	0644
SMTP.php	52484 bytes	0644
error_log	1224 bytes	0644
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