# $Id$
#
# Copyright (C) 2009--2012  Internet Systems Consortium ("ISC")
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
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# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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# PERFORMANCE OF THIS SOFTWARE.
#
# Portions copyright (C) 2007--2008  American Registry for Internet Numbers ("ARIN")
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND ARIN DISCLAIMS ALL WARRANTIES WITH
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS.  IN NO EVENT SHALL ARIN BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
# PERFORMANCE OF THIS SOFTWARE.

"""
RPKI publication control protocol.

Per IETF SIDR WG discussion, this is now separate from the publication
protocol itself.
"""

import logging
import rpki.resource_set
import rpki.x509
import rpki.sql
import rpki.exceptions
import rpki.xml_utils
import rpki.http
import rpki.up_down
import rpki.relaxng
import rpki.sundial
import rpki.log

logger = logging.getLogger(__name__)


class publication_control_namespace(object):
  """
  XML namespace parameters for publication control protocol.
  """

  xmlns = "http://www.hactrn.net/uris/rpki/publication-control/"
  nsmap = { None : xmlns }


class control_elt(rpki.xml_utils.data_elt, rpki.sql.sql_persistent, publication_control_namespace):
  """
  Virtual class for control channel objects.
  """

  pass


class config_elt(control_elt):
  """
  <config/> element.  This is a little weird because there should
  never be more than one row in the SQL config table, but we have to
  put the BPKI CRL somewhere and SQL is the least bad place available.

  So we reuse a lot of the SQL machinery, but we nail config_id at 1,
  we don't expose it in the XML protocol, and we only support the get
  and set actions.
  """

  attributes = ("action", "tag")
  element_name = "config"
  elements = ("bpki_crl",)

  sql_template = rpki.sql.template(
    "config",
    "config_id",
    ("bpki_crl", rpki.x509.CRL))

  wired_in_config_id = 1

  def startElement(self, stack, name, attrs):
    """
    StartElement() handler for config object.  This requires special
    handling because of the weird way we treat config_id.
    """
    control_elt.startElement(self, stack, name, attrs)
    self.config_id = self.wired_in_config_id

  @classmethod
  def fetch(cls, gctx):
    """
    Fetch the config object from SQL.  This requires special handling
    because of the weird way we treat config_id.
    """
    return cls.sql_fetch(gctx, cls.wired_in_config_id)

  def serve_set(self, r_msg, cb, eb):
    """
    Handle a set action.  This requires special handling because
    config doesn't support the create method.
    """
    if self.sql_fetch(self.gctx, self.config_id) is None:
      control_elt.serve_create(self, r_msg, cb, eb)
    else:
      control_elt.serve_set(self, r_msg, cb, eb)

  def serve_fetch_one_maybe(self):
    """
    Find the config object on which a get or set method should
    operate.
    """
    return self.sql_fetch(self.gctx, self.config_id)


class client_elt(control_elt):
  """
  <client/> element.
  """

  element_name = "client"
  attributes = ("action", "tag", "client_handle", "base_uri")
  elements = ("bpki_cert", "bpki_glue")
  booleans = ("clear_replay_protection",)

  sql_template = rpki.sql.template(
    "client",
    "client_id",
    "client_handle",
    "base_uri",
    ("bpki_cert", rpki.x509.X509),
    ("bpki_glue", rpki.x509.X509),
    ("last_cms_timestamp", rpki.sundial.datetime))

  base_uri  = None
  bpki_cert = None
  bpki_glue = None
  last_cms_timestamp = None

  def serve_post_save_hook(self, q_pdu, r_pdu, cb, eb):
    """
    Extra server actions for client_elt.
    """
    actions = []
    if q_pdu.clear_replay_protection:
      actions.append(self.serve_clear_replay_protection)
    def loop(iterator, action):
      action(iterator, eb)
    rpki.async.iterator(actions, loop, cb)

  def serve_clear_replay_protection(self, cb, eb):
    """
    Handle a clear_replay_protection action for this client.
    """
    self.last_cms_timestamp = None
    self.sql_mark_dirty()
    cb()

  def serve_fetch_one_maybe(self):
    """
    Find the client object on which a get, set, or destroy method
    should operate, or which would conflict with a create method.
    """
    return self.sql_fetch_where1(self.gctx, "client_handle = %s", (self.client_handle,))

  def serve_fetch_all(self):
    """
    Find client objects on which a list method should operate.
    """
    return self.sql_fetch_all(self.gctx)

  def check_allowed_uri(self, uri):
    """
    Make sure that a target URI is within this client's allowed URI space.
    """
    if not uri.startswith(self.base_uri):
      raise rpki.exceptions.ForbiddenURI


class report_error_elt(rpki.xml_utils.text_elt, publication_control_namespace):
  """
  <report_error/> element.
  """

  element_name = "report_error"
  attributes = ("tag", "error_code")
  text_attribute = "error_text"

  error_text = None

  @classmethod
  def from_exception(cls, e, tag = None):
    """
    Generate a <report_error/> element from an exception.
    """
    self = cls()
    self.tag = tag
    self.error_code = e.__class__.__name__
    self.error_text = str(e)
    return self

  def __str__(self):
    s = ""
    if getattr(self, "tag", None) is not None:
      s += "[%s] " % self.tag
    s += self.error_code
    if getattr(self, "error_text", None) is not None:
      s += ": " + self.error_text
    return s

  def raise_if_error(self):
    """
    Raise exception associated with this <report_error/> PDU.
    """
    t = rpki.exceptions.__dict__.get(self.error_code)
    if isinstance(t, type) and issubclass(t, rpki.exceptions.RPKI_Exception):
      raise t(getattr(self, "text", None))
    else:
      raise rpki.exceptions.BadPublicationReply("Unexpected response from pubd: %s" % self)


class msg(rpki.xml_utils.msg, publication_control_namespace):
  """
  Publication control PDU.
  """

  ## @var version
  # Protocol version
  version = 1

  ## @var pdus
  # Dispatch table of PDUs for this protocol.
  pdus = dict((x.element_name, x) for x in (config_elt, client_elt, report_error_elt))

  def serve_top_level(self, gctx, cb):
    """
    Serve one msg PDU.
    """
    if not self.is_query():
      raise rpki.exceptions.BadQuery("Message type is not query")
    r_msg = self.__class__.reply()

    def loop(iterator, q_pdu):

      def fail(e):
        if not isinstance(e, rpki.exceptions.NotFound):
          logger.exception("Exception processing PDU %r", q_pdu)
        r_msg.append(report_error_elt.from_exception(e, q_pdu.tag))
        cb(r_msg)

      try:
        q_pdu.gctx = gctx
        q_pdu.serve_dispatch(r_msg, iterator, fail)
      except (rpki.async.ExitNow, SystemExit):
        raise
      except Exception, e:
        fail(e)

    def done():
      cb(r_msg)

    rpki.async.iterator(self, loop, done)


class sax_handler(rpki.xml_utils.sax_handler):
  """
  SAX handler for publication control protocol.
  """

  pdu = msg
  name = "msg"
  version = "1"


class cms_msg(rpki.x509.XML_CMS_object):
  """
  Class to hold a CMS-signed publication control PDU.
  """

  encoding = "us-ascii"
  schema = rpki.relaxng.publication_control
  saxify = sax_handler.saxify