Net_SSH2::_login_helper PHP Method

    function _login_helper($username, $password = null)
    {
        if (!($this->bitmap & NET_SSH2_MASK_CONNECTED)) {
            return false;
        }
        if (!($this->bitmap & NET_SSH2_MASK_LOGIN_REQ)) {
            $packet = pack('CNa*', NET_SSH2_MSG_SERVICE_REQUEST, strlen('ssh-userauth'), 'ssh-userauth');
            if (!$this->_send_binary_packet($packet)) {
                return false;
            }
            $response = $this->_get_binary_packet();
            if ($response === false) {
                user_error('Connection closed by server');
                return false;
            }
            extract(unpack('Ctype', $this->_string_shift($response, 1)));
            if ($type != NET_SSH2_MSG_SERVICE_ACCEPT) {
                user_error('Expected SSH_MSG_SERVICE_ACCEPT');
                return false;
            }
            $this->bitmap |= NET_SSH2_MASK_LOGIN_REQ;
        }
        if (strlen($this->last_interactive_response)) {
            return !is_string($password) && !is_array($password) ? false : $this->_keyboard_interactive_process($password);
        }
        // although PHP5's get_class() preserves the case, PHP4's does not
        if (is_object($password)) {
            switch (strtolower(get_class($password))) {
                case 'crypt_rsa':
                    return $this->_privatekey_login($username, $password);
                case 'system_ssh_agent':
                    return $this->_ssh_agent_login($username, $password);
            }
        }
        if (is_array($password)) {
            if ($this->_keyboard_interactive_login($username, $password)) {
                $this->bitmap |= NET_SSH2_MASK_LOGIN;
                return true;
            }
            return false;
        }
        if (!isset($password)) {
            $packet = pack('CNa*Na*Na*', NET_SSH2_MSG_USERAUTH_REQUEST, strlen($username), $username, strlen('ssh-connection'), 'ssh-connection', strlen('none'), 'none');
            if (!$this->_send_binary_packet($packet)) {
                return false;
            }
            $response = $this->_get_binary_packet();
            if ($response === false) {
                user_error('Connection closed by server');
                return false;
            }
            extract(unpack('Ctype', $this->_string_shift($response, 1)));
            switch ($type) {
                case NET_SSH2_MSG_USERAUTH_SUCCESS:
                    $this->bitmap |= NET_SSH2_MASK_LOGIN;
                    return true;
                    //case NET_SSH2_MSG_USERAUTH_FAILURE:
                //case NET_SSH2_MSG_USERAUTH_FAILURE:
                default:
                    return false;
            }
        }
        $packet = pack('CNa*Na*Na*CNa*', NET_SSH2_MSG_USERAUTH_REQUEST, strlen($username), $username, strlen('ssh-connection'), 'ssh-connection', strlen('password'), 'password', 0, strlen($password), $password);
        // remove the username and password from the logged packet
        if (!defined('NET_SSH2_LOGGING')) {
            $logged = null;
        } else {
            $logged = pack('CNa*Na*Na*CNa*', NET_SSH2_MSG_USERAUTH_REQUEST, strlen('username'), 'username', strlen('ssh-connection'), 'ssh-connection', strlen('password'), 'password', 0, strlen('password'), 'password');
        }
        if (!$this->_send_binary_packet($packet, $logged)) {
            return false;
        }
        $response = $this->_get_binary_packet();
        if ($response === false) {
            user_error('Connection closed by server');
            return false;
        }
        extract(unpack('Ctype', $this->_string_shift($response, 1)));
        switch ($type) {
            case NET_SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ:
                // in theory, the password can be changed
                if (defined('NET_SSH2_LOGGING')) {
                    $this->message_number_log[count($this->message_number_log) - 1] = 'NET_SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ';
                }
                extract(unpack('Nlength', $this->_string_shift($response, 4)));
                $this->errors[] = 'SSH_MSG_USERAUTH_PASSWD_CHANGEREQ: ' . utf8_decode($this->_string_shift($response, $length));
                return $this->_disconnect(NET_SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER);
            case NET_SSH2_MSG_USERAUTH_FAILURE:
                // can we use keyboard-interactive authentication?  if not then either the login is bad or the server employees
                // multi-factor authentication
                extract(unpack('Nlength', $this->_string_shift($response, 4)));
                $auth_methods = explode(',', $this->_string_shift($response, $length));
                extract(unpack('Cpartial_success', $this->_string_shift($response, 1)));
                $partial_success = $partial_success != 0;
                if (!$partial_success && in_array('keyboard-interactive', $auth_methods)) {
                    if ($this->_keyboard_interactive_login($username, $password)) {
                        $this->bitmap |= NET_SSH2_MASK_LOGIN;
                        return true;
                    }
                    return false;
                }
                return false;
            case NET_SSH2_MSG_USERAUTH_SUCCESS:
                $this->bitmap |= NET_SSH2_MASK_LOGIN;
                return true;
        }
        return false;
    }