# Authors:
#   Andrew Wnuk <awnuk@redhat.com>
#   Jason Gerard DeRose <jderose@redhat.com>
#   Rob Crittenden <rcritten@@redhat.com>
#
# Copyright (C) 2009  Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; version 2 only
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

"""
Backend plugin for RA using Dogtag.
"""

from ipalib import api, SkipPluginModule
if api.env.ra_plugin != 'dogtag':
    # In this case, abort loading this plugin module...
    raise SkipPluginModule(reason='dogtag not selected as RA plugin')
import os
from httplib import HTTPConnection
from urllib import urlencode
from ipaserver.plugins import rabase
import socket
from ipalib.errors import NetworkError
from ipalib.constants import TYPE_ERROR
from ipapython import nsslib
import nss.nss as nss
import xml.dom.minidom

def get_xml_value(doc, tagname):
    try:
        item_node = doc.getElementsByTagName(tagname)
        return item_node[0].childNodes[0].data
    except IndexError:
        return None

class ra(rabase.rabase):
    """
    Request Authority backend plugin.
    """
    def __init__(self):
        if api.env.home:
            self.sec_dir = api.env.dot_ipa + os.sep + 'alias'
            self.pwd_file = self.sec_dir + os.sep + '.pwd'
        else:
            self.sec_dir = "/etc/httpd/alias"
            self.pwd_file = "/etc/httpd/alias/pwdfile.txt"
        self.noise_file = self.sec_dir + os.sep + '.noise'
        self.ipa_key_size = "2048"
        self.ipa_certificate_nickname = "ipaCert"
        self.ca_certificate_nickname = "caCert"
        f = open(self.pwd_file, "r")
        self.password = f.readline().strip()
        f.close()
        super(ra, self).__init__()

    def _request(self, url, **kw):
        """
        Perform an HTTP request.

        :param url: The URL to post to.
        :param kw: Keyword arguments to encode into POST body.
        """
        uri = 'http://%s:%s%s' % (self.env.ca_host, self.env.ca_port, url)
        post = urlencode(kw)
        self.info('request %r', uri)
        self.debug('request post %r', post)
        conn = HTTPConnection(self.env.ca_host, self.env.ca_port)
        try:
            conn.request('POST', url,
                body=post,
                headers={'Content-type': 'application/x-www-form-urlencoded'},
            )
        except socket.error, e:
            raise NetworkError(uri=uri, error=e.args[1])
        response = conn.getresponse()
        (status, reason) = (response.status, response.reason)
        data = response.read()
        conn.close()
        self.debug('request status %r', status)
        self.debug('request reason %s', reason)
        self.debug('request data %s', data)
        return (status, reason, data)

    def _sslget(self, url, port, **kw):
        """
        Perform an HTTPS request

        :param url: The URL to post to.
        :param kw: Keyword arguments to encode into POST body.
        """
        uri = 'https://%s:%d%s' % (self.env.ca_host, port, url)
        post = urlencode(kw)
        self.info('sslget %r', uri)
        self.debug('sslget post %r', post)
        headers = {"Content-type": "application/x-www-form-urlencoded",
                   "Accept": "text/plain"}
        conn = nsslib.NSSConnection(self.env.ca_host, port, dbdir=self.sec_dir)
        conn.sslsock.set_client_auth_data_callback(nsslib.client_auth_data_callback, self.ipa_certificate_nickname, self.password, nss.get_default_certdb())
        conn.set_debuglevel(10)
        conn.request("POST", url, post, headers)
        res = conn.getresponse()
        (status, reason) = (res.status, res.reason)
        data = res.read()
        conn.close()

        self.debug('sslget status %r', status)
        self.debug('sslget reason %s', reason)
        self.debug('sslget output %s', data)
        return (status, reason, data)

    def check_request_status(self, request_id):
        """
        Check status of a certificate signing request.

        :param request_id: request ID
        """
        self.debug('%s.check_request_status()', self.fullname)
        (s, r, data) = self._request('/ca/ee/ca/checkRequest',
            requestId=request_id,
            xmlOutput='true',
        )
        response = {'status': '2'}
        if data is not None:
            request_status = self.__find_substring(
                data, 'header.status = "', '"'
            )
            if request_status is not None:
                response['status'] = '0'
                response['request_status'] = request_status
                serial_number = self.__find_substring(
                    data, 'record.serialNumber="', '"'
                )
                if serial_number is not None:
                    # This was "0x"+serial_number, but we should return it in
                    # the same form used as arg to get_certificate(), etc.
                    response['serial_number'] = serial_number
            request_id = self.__find_substring(
                data, 'header.requestId = "', '"'
            )
            if request_id is not None:
                response['request_id'] = request_id
            error = self.__find_substring(
                data, 'fixed.unexpectedError = "', '"'
            )
            if error is not None:
                response['error'] = error
        return response

    def get_certificate(self, serial_number=None):
        """
        Retrieve an existing certificate.

        :param serial_number: certificate serial number
        """
        self.debug('%s.get_certificate()', self.fullname)
        issued_certificate = None
        (status, reason, stdout) = self._sslget(
            '/ca/agent/ca/displayBySerial',
            self.env.ca_agent_port,
            serialNumber=serial_number,
            xmlOutput='true',
        )
        response = {}
        if (status == 200):
            issued_certificate = self.__find_substring(
                stdout, 'header.certChainBase64 = "', '"'
            )
            if issued_certificate is not None:
                response['status'] = '0'
                issued_certificate = issued_certificate.replace('\\r', '')
                issued_certificate = issued_certificate.replace('\\n', '')
                self.debug('IPA-RA: issued_certificate: %s', issued_certificate)
                response['certificate'] = issued_certificate
            else:
                response['status'] = '1'
            revocation_reason = self.__find_substring(
                stdout, 'header.revocationReason = ', ';'
            )
            if revocation_reason is not None:
                response['revocation_reason'] = revocation_reason
        else:
            response['status'] = str(status)
        return response

    def request_certificate(self, csr, request_type='pkcs10'):
        """
        Submit certificate signing request.

        :param csr: The certificate signing request.
        :param request_type: The request type (defaults to ``'pkcs10'``).
        """
        self.debug('%s.request_certificate()', self.fullname)
        certificate = None
        (status, reason, stdout) = self._sslget('/ca/ee/ca/profileSubmit',
            self.env.ca_ee_port,
            profileId='caRAserverCert',
            cert_request_type=request_type,
            cert_request=csr,
            xmlOutput='true',
        )
        response = {}
        if (status == 200):
            doc = xml.dom.minidom.parseString(stdout)

            status = get_xml_value(doc, "Status")
            if status is not None:
                response["status"] = status
            request_id = get_xml_value(doc, "Id")
            if request_id is not None:
                response["request_id"] = request_id
            serial_number = get_xml_value(doc, "serialno")
            if serial_number is not None:
                response["serial_number"] = ("0x%s" % serial_number)
            subject = get_xml_value(doc, "SubjectDN")
            if subject is not None:
                response["subject"] = subject
            certificate = get_xml_value(doc, "b64")
            if certificate is not None:
                response["certificate"] = certificate
            if response.has_key("status") is False:
                response["status"] = "2"

            doc.unlink()
        else:
            response["status"] = str(status)
        return response

    def revoke_certificate(self, serial_number, revocation_reason=0):
        """
        Revoke a certificate.

        The integer ``revocation_reason`` code must have one of these values:

            * ``0`` - unspecified
            * ``1`` - keyCompromise
            * ``2`` - cACompromise
            * ``3`` - affiliationChanged
            * ``4`` - superseded
            * ``5`` - cessationOfOperation
            * ``6`` - certificateHold
            * ``8`` - removeFromCRL
            * ``9`` - privilegeWithdrawn
            * ``10`` - aACompromise

        Note that reason code ``7`` is not used.  See RFC 5280 for more details:

            http://www.ietf.org/rfc/rfc5280.txt

        :param serial_number: Certificate serial number.
        :param revocation_reason: Integer code of revocation reason.
        """
        self.debug('%s.revoke_certificate()', self.fullname)
        if type(revocation_reason) is not int:
            raise TYPE_ERROR('revocation_reason', int, revocation_reason,
                type(revocation_reason)
            )
        response = {}
        (status, reason, stdout) = self._sslget('/ca/agent/ca/doRevoke',
            self.env.ca_agent_port,
            op='revoke',
            revocationReason=revocation_reason,
            revokeAll='(certRecordId=%s)' % serial_number,
            totalRecordCount=1,
        )
        if status == 200:
            response['status'] = '0'
            if (stdout.find('revoked = "yes"') > -1):
                response['revoked'] = True
            else:
                response['revoked'] = False
        else:
            response['status'] = str(status)
        return response

    def take_certificate_off_hold(self, serial_number):
        """
        Take revoked certificate off hold.

        :param serial_number: Certificate serial number.
        """
        response = {}
        self.debug('%s.take_certificate_off_hold()', self.fullname)
        (status, reason, stdout) = self._sslget('/ca/agent/ca/doUnrevoke',
            self.env.ca_agent_port,
            serialNumber=serial_number,
        )
        if (status == 0):
            if (stdout.find('unrevoked = "yes"') > -1):
                response['taken_off_hold'] = True
            else:
                response['taken_off_hold'] = False
        else:
            response['status'] = str(status)
        return response

    def __find_substring(self, str, str1, str2):
        sub_str = None
        k0 = len(str)
        k1 = str.find(str1)
        k2 = len(str1)
        if (k0 > 0 and k1 > -1 and k2 > 0 and k0 > k1 + k2):
            sub_str = str[k1+k2:]
            k3 = len(sub_str)
            k4 = sub_str.find(str2)
            if (k3 > 0 and k4 > -1 and k3 > k4):
                sub_str = sub_str[:k4]
        return sub_str

api.register(ra)