"""
RPKI "left-right" protocol.

$Id$

Copyright (C) 2009  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.

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,
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.

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.
"""

import traceback
import rpki.resource_set, rpki.x509, rpki.sql, rpki.exceptions, rpki.xml_utils
import rpki.https, rpki.up_down, rpki.relaxng, rpki.sundial, rpki.log, rpki.roa
import rpki.publication, rpki.async

# Enforce strict checking of XML "sender" field in up-down protocol
enforce_strict_up_down_xml_sender = False

class left_right_namespace(object):
  """
  XML namespace parameters for left-right protocol.
  """

  xmlns = "http://www.hactrn.net/uris/rpki/left-right-spec/"
  nsmap = { None : xmlns }

class data_elt(rpki.xml_utils.data_elt, rpki.sql.sql_persistent, left_right_namespace):
  """
  Virtual class for top-level left-right protocol data elements.
  """

  handles = ()

  self_id = None

  def self(self):
    """Fetch self object to which this object links."""
    return self_elt.sql_fetch(self.gctx, self.self_id)

  def bsc(self):
    """Return BSC object to which this object links."""
    return bsc_elt.sql_fetch(self.gctx, self.bsc_id)

  def make_reply_clone_hook(self, r_pdu):
    """Set self_handle when cloning."""
    r_pdu.self_handle = self.self_handle

  @classmethod
  def serve_fetch_handle(cls, gctx, self_id, handle):
    """
    Find an object based on its handle.
    """
    return cls.sql_fetch_where1(gctx, cls.element_name + "_handle = %s AND self_id = %s", (handle, self_id))

  def serve_fetch_one_maybe(self):
    """
    Find the object on which a get, set, or destroy method should
    operate, or which would conflict with a create method.
    """
    where = "%s.%s_handle = %%s AND %s.self_id = self.self_id AND self.self_handle = %%s" % ((self.element_name,) * 3)
    args = (getattr(self, self.element_name + "_handle"), self.self_handle)
    return self.sql_fetch_where1(self.gctx, where, args, "self")

  def serve_fetch_all(self):
    """
    Find the objects on which a list method should operate.
    """
    where = "%s.self_id = self.self_id and self.self_handle = %%s" % self.element_name
    return self.sql_fetch_where(self.gctx, where, (self.self_handle,), "self")
  
  def serve_pre_save_hook(self, q_pdu, r_pdu, cb, eb):
    """
    Hook to do _handle => _id translation before saving.
    """
    for tag, elt in self.handles:
      id_name = tag + "_id"
      if getattr(r_pdu, id_name, None) is None:
        x = elt.serve_fetch_handle(self.gctx, self.self_id, getattr(q_pdu, tag + "_handle"))
        if x is None:
          raise rpki.exceptions.NotFound
        val = getattr(x, id_name)
        rpki.log.debug("Setting %r and %r %s = %r" % (self, r_pdu, id_name, val))
        setattr(self, id_name, val)
        setattr(r_pdu, id_name, val)
    cb()

  def unimplemented_control(self, *controls):
    """
    Uniform handling for unimplemented control operations.
    """
    unimplemented = [x for x in controls if getattr(self, x, False)]
    if unimplemented:
      raise rpki.exceptions.NotImplementedYet, "Unimplemented control %s" % ", ".join(unimplemented)

class self_elt(data_elt):
  """
  <self/> element.
  """

  element_name = "self"
  attributes = ("action", "tag", "self_handle", "crl_interval", "regen_margin")
  elements = ("bpki_cert", "bpki_glue")
  booleans = ("rekey", "reissue", "revoke", "run_now", "publish_world_now")

  sql_template = rpki.sql.template("self", "self_id", "self_handle",
                                   "use_hsm", "crl_interval", "regen_margin",
                                   ("bpki_cert", rpki.x509.X509), ("bpki_glue", rpki.x509.X509))
  handles = ()

  use_hsm = False
  crl_interval = None
  regen_margin = None
  bpki_cert = None
  bpki_glue = None

  def bscs(self):
    """Fetch all BSC objects that link to this self object."""
    return bsc_elt.sql_fetch_where(self.gctx, "self_id = %s", (self.self_id,))

  def repositories(self):
    """Fetch all repository objects that link to this self object."""
    return repository_elt.sql_fetch_where(self.gctx, "self_id = %s", (self.self_id,))

  def parents(self):
    """Fetch all parent objects that link to this self object."""
    return parent_elt.sql_fetch_where(self.gctx, "self_id = %s", (self.self_id,))

  def children(self):
    """Fetch all child objects that link to this self object."""
    return child_elt.sql_fetch_where(self.gctx, "self_id = %s", (self.self_id,))

  def route_origins(self):
    """Fetch all route_origin objects that link to this self object."""
    return route_origin_elt.sql_fetch_where(self.gctx, "self_id = %s", (self.self_id,))

  def serve_post_save_hook(self, q_pdu, r_pdu, cb, eb):
    """
    Extra server actions for self_elt.
    """
    rpki.log.trace()
    if q_pdu.rekey:
      self.serve_rekey(cb, eb)
    elif q_pdu.revoke:
      self.serve_revoke(cb, eb)
    else:
      self.unimplemented_control("reissue", "run_now", "publish_world_now")
      cb()

  def serve_rekey(self, cb, eb):
    """
    Handle a left-right rekey action for this self.
    """
    rpki.log.trace()

    def loop(iterator, parent):
      parent.serve_rekey(iterator, eb)

    rpki.async.iterator(self.parents(), loop, cb)

  def serve_revoke(self, cb, eb):
    """
    Handle a left-right revoke action for this self.
    """
    rpki.log.trace()

    def loop(iterator, parent):
      parent.serve_revoke(iterator, eb)

    rpki.async.iterator(self.parents(), loop, cb)

  def serve_fetch_one_maybe(self):
    """
    Find the self object upon which a get, set, or destroy action
    should operate, or which would conflict with a create method.
    """
    return self.serve_fetch_handle(self.gctx, None, self.self_handle)

  @classmethod
  def serve_fetch_handle(cls, gctx, self_id, self_handle):
    """
    Find a self object based on its self_handle.
    """
    return cls.sql_fetch_where1(gctx, "self_handle = %s", self_handle)

  def serve_fetch_all(self):
    """
    Find the self objects upon which a list action should operate.
    This is different from the list action for all other objects,
    where list only works within a given self_id context.
    """
    return self.sql_fetch_all(self.gctx)

  def client_poll(self, callback):
    """
    Run the regular client poll cycle with each of this self's parents
    in turn.
    """

    rpki.log.trace()

    def parent_loop(parent_iterator, parent):

      def got_list(r_msg):
        ca_map = dict((ca.parent_resource_class, ca) for ca in parent.cas())

        def class_loop(class_iterator, rc):

          def class_update_failed(e):
            rpki.log.error(traceback.format_exc())
            rpki.log.warn("Couldn't update class, skipping: %s" % e)
            class_iterator()

          def class_create_failed(e):
            rpki.log.error(traceback.format_exc())
            rpki.log.warn("Couldn't create class, skipping: %s" % e)
            class_iterator()

          if rc.class_name in ca_map:
            ca = ca_map[rc.class_name]
            del  ca_map[rc.class_name]
            ca.check_for_updates(parent, rc, class_iterator, class_update_failed)
          else:
            rpki.rpki_engine.ca_obj.create(parent, rc, class_iterator, class_create_failed)

        def class_done():

          def ca_loop(iterator, ca):
            ca.delete(parent, iterator)
            
          def ca_done():
            self.gctx.sql.sweep()
            parent_iterator()

          rpki.async.iterator(ca_map.values(), ca_loop, ca_done)

        rpki.async.iterator(r_msg.payload.classes, class_loop, class_done)

      def list_failed(e):
        rpki.log.error(traceback.format_exc())
        rpki.log.warn("Couldn't get resource class list from parent %r, skipping: %s" % (parent, e))

      rpki.up_down.list_pdu.query(parent, got_list, list_failed)

    rpki.async.iterator(self.parents(), parent_loop, callback)

  def update_children(self, cb):
    """
    Check for updated IRDB data for all of this self's children and
    issue new certs as necessary.  Must handle changes both in
    resources and in expiration date.
    """

    rpki.log.trace()

    now = rpki.sundial.now()

    rsn = now + rpki.sundial.timedelta(seconds = self.regen_margin)

    def loop1(iterator1, child):

      def got_resources(irdb_resources):

        def loop2(iterator2, child_cert):

          ca_detail = child_cert.ca_detail()

          if ca_detail.state == "active":
            old_resources = child_cert.cert.get_3779resources()
            new_resources = irdb_resources.intersection(old_resources)

            if old_resources != new_resources or (old_resources.valid_until < rsn  and irdb_resources.valid_until > now):
              rpki.log.debug("Need to reissue child certificate SKI %s" % child_cert.cert.gSKI())

              def reissue_failed(e):
                rpki.log.error(traceback.format_exc())
                rpki.log.warn("Couldn't reissue child_cert %r, skipping: %s" % (child_cert, e))
                iterator2()

              child_cert.reissue(
                ca_detail = ca_detail,
                resources = new_resources,
                callback  = iterator2.ignore,
                errback   = reissue_failed)
              return

            if old_resources.valid_until < now:
              rpki.log.debug("Child certificate SKI %s has expired: cert.valid_until %s, irdb.valid_until %s"
                             % (child_cert.cert.gSKI(), old_resources.valid_until, irdb_resources.valid_until))
              ca = ca_detail.ca()
              parent = ca.parent()
              repository = parent.repository()
              child_cert.sql_delete()

              def withdraw():
                repository.withdraw(child_cert.cert, child_cert.uri(ca), iterator2, withdraw_failed)

              def manifest_failed(e):
                rpki.log.error(traceback.format_exc())
                rpki.log.warn("Couldn't reissue manifest for %r, skipping: %s" % (ca_detail, e))
                iterator2()

              def withdraw_failed(e):
                rpki.log.error(traceback.format_exc())
                rpki.log.warn("Couldn't withdraw old child_cert %r, skipping: %s" % (child_cert, e))
                iterator2()

              ca_detail.generate_manifest(withdraw, manifest_failed)
              return

          iterator2()

        rpki.async.iterator(child_certs, loop2, iterator1)

      def irdb_lookup_failed(e):
        rpki.log.error(traceback.format_exc())
        rpki.log.warn("Couldn't look up child's resources in IRDB, skipping child %r: %s" % (child, e))
        iterator1()

      child_certs = child.child_certs()
      if child_certs:
        self.gctx.irdb_query(child.self().self_handle, child.child_handle, got_resources, irdb_lookup_failed)
      else:
        iterator1()

    rpki.async.iterator(self.children(), loop1, cb)


  def regenerate_crls_and_manifests(self, cb):
    """
    Generate new CRLs and manifests as necessary for all of this
    self's CAs.  Extracting nextUpdate from a manifest is hard at the
    moment due to implementation silliness, so for now we generate a
    new manifest whenever we generate a new CRL

    This method also cleans up tombstones left behind by revoked
    ca_detail objects, since we're walking through the relevant
    portions of the database anyway.
    """

    rpki.log.trace()

    now = rpki.sundial.now()

    def loop1(iterator1, parent):
      repository = parent.repository()

      def loop2(iterator2, ca):

        def fail2(e):
          rpki.log.error(traceback.format_exc())
          rpki.log.warn("Couldn't regenerate CRLs and manifests for CA %r, skipping: %s" % (ca, e))
          iterator2()

        def loop3(iterator3, ca_detail):
          ca_detail.delete(ca, repository, iterator3, fail2)

        def done3():

          ca_detail = ca.fetch_active()

          def do_crl():
            ca_detail.generate_crl(do_manifest, fail2)

          def do_manifest():
            ca_detail.generate_manifest(iterator2, fail2)

          if ca_detail is not None and now > ca_detail.latest_crl.getNextUpdate():
            do_crl()
          else:
            iterator2()

        rpki.async.iterator([x for x in ca.fetch_revoked() if now > x.latest_crl.getNextUpdate()], loop3, done3)

      rpki.async.iterator(parent.cas(), loop2, iterator1)

    rpki.async.iterator(self.parents(), loop1, cb)


  def update_roas(self, cb):
    """
    Generate or update ROAs for this self's route_origin objects.
    """

    def loop(iterator, route_origin):
      route_origin.update_roa(iterator)

    rpki.async.iterator(self.route_origins(), loop, cb)


class bsc_elt(data_elt):
  """
  <bsc/> (Business Signing Context) element.
  """
  
  element_name = "bsc"
  attributes = ("action", "tag", "self_handle", "bsc_handle", "key_type", "hash_alg", "key_length")
  elements = ("signing_cert", "signing_cert_crl", "pkcs10_request")
  booleans = ("generate_keypair",)

  sql_template = rpki.sql.template("bsc", "bsc_id", "bsc_handle",
                                   "self_id", "hash_alg",
                                   ("private_key_id", rpki.x509.RSA),
                                   ("pkcs10_request", rpki.x509.PKCS10),
                                   ("signing_cert", rpki.x509.X509),
                                   ("signing_cert_crl", rpki.x509.CRL))
  handles = (("self", self_elt),)

  private_key_id = None
  pkcs10_request = None
  signing_cert = None
  signing_cert_crl = None

  def repositories(self):
    """Fetch all repository objects that link to this BSC object."""
    return repository_elt.sql_fetch_where(self.gctx, "bsc_id = %s", (self.bsc_id,))

  def parents(self):
    """Fetch all parent objects that link to this BSC object."""
    return parent_elt.sql_fetch_where(self.gctx, "bsc_id = %s", (self.bsc_id,))

  def children(self):
    """Fetch all child objects that link to this BSC object."""
    return child_elt.sql_fetch_where(self.gctx, "bsc_id = %s", (self.bsc_id,))

  def serve_pre_save_hook(self, q_pdu, r_pdu, cb, eb):
    """
    Extra server actions for bsc_elt -- handle key generation.  For
    now this only allows RSA with SHA-256.
    """
    if q_pdu.generate_keypair:
      assert q_pdu.key_type in (None, "rsa") and q_pdu.hash_alg in (None, "sha256")
      self.private_key_id = rpki.x509.RSA.generate(keylength = q_pdu.key_length or 2048)
      self.pkcs10_request = rpki.x509.PKCS10.create(self.private_key_id)
      r_pdu.pkcs10_request = self.pkcs10_request
    data_elt.serve_pre_save_hook(self, q_pdu, r_pdu, cb, eb)

class repository_elt(data_elt):
  """
  <repository/> element.
  """

  element_name = "repository"
  attributes = ("action", "tag", "self_handle", "repository_handle", "bsc_handle", "peer_contact_uri")
  elements = ("bpki_cms_cert", "bpki_cms_glue", "bpki_https_cert", "bpki_https_glue")

  sql_template = rpki.sql.template("repository", "repository_id", "repository_handle",
                                   "self_id", "bsc_id", "peer_contact_uri",
                                   ("bpki_cms_cert", rpki.x509.X509), ("bpki_cms_glue", rpki.x509.X509),
                                   ("bpki_https_cert", rpki.x509.X509), ("bpki_https_glue", rpki.x509.X509))
  handles = (("self", self_elt), ("bsc", bsc_elt))

  bpki_cms_cert = None
  bpki_cms_glue = None
  bpki_https_cert = None
  bpki_https_glue = None

  def parents(self):
    """Fetch all parent objects that link to this repository object."""
    return parent_elt.sql_fetch_where(self.gctx, "repository_id = %s", (self.repository_id,))

  def call_pubd(self, callback, errback, *pdus):
    """
    Send a message to publication daemon and return the response.
    """
    rpki.log.trace()
    bsc = self.bsc()
    q_msg = rpki.publication.msg(pdus)
    q_msg.type = "query"
    q_cms = rpki.publication.cms_msg.wrap(q_msg, bsc.private_key_id, bsc.signing_cert, bsc.signing_cert_crl)
    bpki_ta_path = (self.gctx.bpki_ta, self.self().bpki_cert, self.self().bpki_glue, self.bpki_https_cert, self.bpki_https_glue)

    def done(r_cms):
      try:
        r_msg = rpki.publication.cms_msg.unwrap(r_cms, bpki_ta_path)
        if len(r_msg) != 1 or isinstance(r_msg[0], rpki.publication.report_error_elt):
          raise rpki.exceptions.BadPublicationReply, "Unexpected response from pubd: %s" % msg
        callback()
      except (rpki.async.ExitNow, SystemExit):
        raise
      except Exception, edata:
        errback(edata)

    rpki.https.client(
      client_key   = bsc.private_key_id,
      client_cert  = bsc.signing_cert,
      server_ta    = bpki_ta_path,
      url          = self.peer_contact_uri,
      msg          = q_cms,
      callback     = done,
      errback      = errback)

  def publish(self, obj, uri, callback, errback):
    """
    Publish one object in the repository.
    """
    rpki.log.trace()
    rpki.log.info("Publishing %s as %s" % (repr(obj), repr(uri)))
    self.call_pubd(callback, errback, rpki.publication.obj2elt[type(obj)].make_pdu(action = "publish", uri = uri, payload = obj))

  def withdraw(self, obj, uri, callback, errback):
    """
    Withdraw one object from the repository.
    """
    rpki.log.trace()
    rpki.log.info("Withdrawing %s from at %s" % (repr(obj), repr(uri)))
    self.call_pubd(callback, errback, rpki.publication.obj2elt[type(obj)].make_pdu(action = "withdraw", uri = uri))

class parent_elt(data_elt):
  """
  <parent/> element.
  """

  element_name = "parent"
  attributes = ("action", "tag", "self_handle", "parent_handle", "bsc_handle", "repository_handle",
                "peer_contact_uri", "sia_base", "sender_name", "recipient_name")
  elements = ("bpki_cms_cert", "bpki_cms_glue", "bpki_https_cert", "bpki_https_glue")
  booleans = ("rekey", "reissue", "revoke")

  sql_template = rpki.sql.template("parent", "parent_id", "parent_handle",
                                   "self_id", "bsc_id", "repository_id",
                                   ("bpki_cms_cert", rpki.x509.X509), ("bpki_cms_glue", rpki.x509.X509),
                                   ("bpki_https_cert", rpki.x509.X509), ("bpki_https_glue", rpki.x509.X509),
                                   "peer_contact_uri", "sia_base", "sender_name", "recipient_name")
  handles = (("self", self_elt), ("bsc", bsc_elt), ("repository", repository_elt))

  bpki_cms_cert = None
  bpki_cms_glue = None
  bpki_https_cert = None
  bpki_https_glue = None

  def repository(self):
    """Fetch repository object to which this parent object links."""
    return repository_elt.sql_fetch(self.gctx, self.repository_id)

  def cas(self):
    """Fetch all CA objects that link to this parent object."""
    return rpki.rpki_engine.ca_obj.sql_fetch_where(self.gctx, "parent_id = %s", (self.parent_id,))

  def serve_post_save_hook(self, q_pdu, r_pdu, cb, eb):
    """
    Extra server actions for parent_elt.
    """
    if q_pdu.rekey:
      self.serve_rekey(cb, eb)
    elif q_pdu.revoke:
      self.serve_revoke(cb, eb)
    else:
      self.unimplemented_control("reissue")
      cb()

  def serve_rekey(self, cb, eb):
    """
    Handle a left-right rekey action for this parent.
    """

    def loop(iterator, ca):
      ca.rekey(iterator, eb)

    rpki.async.iterator(self.cas(), loop, cb)

  def serve_revoke(self, cb, eb):
    """
    Handle a left-right revoke action for this parent.
    """

    def loop(iterator, ca):
      ca.revoke(iterator, eb)

    rpki.async.iterator(self.cas(), loop, cb)

  def query_up_down(self, q_pdu, cb, eb):
    """
    Client code for sending one up-down query PDU to this parent.
    """

    rpki.log.trace()

    bsc = self.bsc()
    if bsc is None:
      raise rpki.exceptions.BSCNotFound, "Could not find BSC %s" % self.bsc_id

    q_msg = rpki.up_down.message_pdu.make_query(
      payload = q_pdu,
      sender = self.sender_name,
      recipient = self.recipient_name)

    q_cms = rpki.up_down.cms_msg.wrap(q_msg, bsc.private_key_id,
                                      bsc.signing_cert,
                                      bsc.signing_cert_crl)

    def unwrap(der):
      r_msg = rpki.up_down.cms_msg.unwrap(der, (self.gctx.bpki_ta,
                                                self.self().bpki_cert, self.self().bpki_glue,
                                                self.bpki_cms_cert, self.bpki_cms_glue))
      r_msg.payload.check_response()
      cb(r_msg)

    rpki.https.client(server_ta    = (self.gctx.bpki_ta,
                                      self.self().bpki_cert, self.self().bpki_glue,
                                      self.bpki_https_cert, self.bpki_https_glue),
                      client_key   = bsc.private_key_id,
                      client_cert  = bsc.signing_cert,
                      msg          = q_cms,
                      url          = self.peer_contact_uri,
                      callback     = unwrap,
                      errback      = eb)

class child_elt(data_elt):
  """
  <child/> element.
  """

  element_name = "child"
  attributes = ("action", "tag", "self_handle", "child_handle", "bsc_handle")
  elements = ("bpki_cert", "bpki_glue")
  booleans = ("reissue", )

  sql_template = rpki.sql.template("child", "child_id", "child_handle",
                                   "self_id", "bsc_id",
                                   ("bpki_cert", rpki.x509.X509),
                                   ("bpki_glue", rpki.x509.X509))

  handles = (("self", self_elt), ("bsc", bsc_elt))

  bpki_cert = None
  bpki_glue = None
  clear_https_ta_cache = False

  def child_certs(self, ca_detail = None, ski = None, unique = False):
    """Fetch all child_cert objects that link to this child object."""
    return rpki.rpki_engine.child_cert_obj.fetch(self.gctx, self, ca_detail, ski, unique)

  def parents(self):
    """Fetch all parent objects that link to self object to which this child object links."""
    return parent_elt.sql_fetch_where(self.gctx, "self_id = %s", (self.self_id,))

  def ca_from_class_name(self, class_name):
    """
    Fetch the CA corresponding to an up-down class_name.
    """
    if not class_name.isdigit():
      raise rpki.exceptions.BadClassNameSyntax, "Bad class name %s" % class_name
    ca = rpki.rpki_engine.ca_obj.sql_fetch(self.gctx, long(class_name))
    if ca is None:
      raise rpki.exceptions.ClassNameUnknown, "Unknown class name %s" % class_name
    parent = ca.parent()
    if self.self_id != parent.self_id:
      raise rpki.exceptions.ClassNameMismatch, "Class name mismatch: child.self_id = %d, parent.self_id = %d" % (self.self_id, parent.self_id)
    return ca

  def serve_post_save_hook(self, q_pdu, r_pdu, cb, eb):
    """
    Extra server actions for child_elt.
    """
    self.unimplemented_control("reissue")
    if self.clear_https_ta_cache:
      self.gctx.clear_https_ta_cache()
      self.clear_https_ta_cache = False
    cb()

  def endElement(self, stack, name, text):
    """
    Handle subelements of <child/> element.  These require special
    handling because modifying them invalidates the HTTPS trust anchor
    cache.
    """
    rpki.xml_utils.data_elt.endElement(self, stack, name, text)
    if name in self.elements:
      self.clear_https_ta_cache = True

  def serve_up_down(self, query, callback):
    """
    Outer layer of server handling for one up-down PDU from this child.
    """

    rpki.log.trace()

    bsc = self.bsc()
    if bsc is None:
      raise rpki.exceptions.BSCNotFound, "Could not find BSC %s" % self.bsc_id
    q_msg = rpki.up_down.cms_msg.unwrap(query, (self.gctx.bpki_ta,
                                                self.self().bpki_cert, self.self().bpki_glue,
                                                self.bpki_cert, self.bpki_glue))
    q_msg.payload.gctx = self.gctx
    if enforce_strict_up_down_xml_sender and q_msg.sender != str(self.child_id):
      raise rpki.exceptions.BadSender, "Unexpected XML sender %s" % q_msg.sender

    def done(r_msg):
      #
      # Exceptions from this point on are problematic, as we have no
      # sane way of reporting errors in the error reporting mechanism.
      # May require refactoring, ignore the issue for now.
      #
      r_cms = rpki.up_down.cms_msg.wrap(r_msg, bsc.private_key_id,
                                        bsc.signing_cert, bsc.signing_cert_crl)
      callback(r_cms)

    try:
      q_msg.serve_top_level(self, done)
    except (rpki.async.ExitNow, SystemExit):
      raise
    except rpki.exceptions.NoActiveCA, data:
      done(q_msg.serve_error(data))
    except Exception, data:
      rpki.log.error(traceback.format_exc())
      done(q_msg.serve_error(data))

class route_origin_elt(data_elt):
  """
  <route_origin/> element.
  """

  element_name = "route_origin"
  attributes = ("action", "tag", "self_handle", "route_origin_handle", "as_number", "ipv4", "ipv6")
  booleans = ("suppress_publication",)

  sql_template = rpki.sql.template("route_origin", "route_origin_id", "route_origin_handle",
                                   "ca_detail_id", "self_id", "as_number",
                                   ("roa", rpki.x509.ROA),
                                   ("cert", rpki.x509.X509))
  handles = (("self", self_elt),)

  ca_detail_id = None
  cert = None
  roa = None

  ## @var publish_ee_separately
  # Whether to publish the ROA EE certificate separately from the ROA.
  publish_ee_separately = False

  def sql_fetch_hook(self):
    """
    Extra SQL fetch actions for route_origin_elt -- handle prefix list.
    """
    self.ipv4 = rpki.resource_set.roa_prefix_set_ipv4.from_sql(
      self.gctx.sql,
      """
          SELECT address, prefixlen, max_prefixlen FROM route_origin_prefix
          WHERE route_origin_id = %s AND address NOT LIKE '%:%'
      """, (self.route_origin_id,))
    self.ipv6 = rpki.resource_set.roa_prefix_set_ipv6.from_sql(
      self.gctx.sql,
      """
          SELECT address, prefixlen, max_prefixlen FROM route_origin_prefix
          WHERE route_origin_id = %s AND address LIKE '%:%'
      """, (self.route_origin_id,))

  def sql_insert_hook(self):
    """
    Extra SQL insert actions for route_origin_elt -- handle address
    ranges.
    """
    if self.ipv4 or self.ipv6:
      self.gctx.sql.executemany(
        """
            INSERT route_origin_prefix (route_origin_id, address, prefixlen, max_prefixlen)
            VALUES (%s, %s, %s, %s)
        """,
        ((self.route_origin_id, x.address, x.prefixlen, x.max_prefixlen)
         for x in (self.ipv4 or []) + (self.ipv6 or [])))
  
  def sql_delete_hook(self):
    """
    Extra SQL delete actions for route_origin_elt -- handle address
    ranges.
    """
    self.gctx.sql.execute("DELETE FROM route_origin_prefix WHERE route_origin_id = %s", (self.route_origin_id,))

  def ca_detail(self):
    """Fetch all ca_detail objects that link to this route_origin object."""
    return rpki.rpki_engine.ca_detail_obj.sql_fetch(self.gctx, self.ca_detail_id)

  def serve_post_save_hook(self, q_pdu, r_pdu, cb, eb):
    """
    Extra server actions for route_origin_elt.
    """
    self.unimplemented_control("suppress_publication")
    cb()

  def startElement(self, stack, name, attrs):
    """
    Handle <route_origin/> element.  This requires special processing
    due to the data types of some of the attributes.
    """
    assert name == "route_origin", "Unexpected name %s, stack %s" % (name, stack)
    self.read_attrs(attrs)
    if self.as_number is not None:
      self.as_number = long(self.as_number)
    if self.ipv4 is not None:
      self.ipv4 = rpki.resource_set.roa_prefix_set_ipv4(self.ipv4)
    if self.ipv6 is not None:
      self.ipv6 = rpki.resource_set.roa_prefix_set_ipv6(self.ipv6)

  def update_roa(self, callback):
    """
    Bring this route_origin's ROA up to date if necesssary.
    """

    def lose(e):
      rpki.log.error(traceback.format_exc())
      rpki.log.warn("Could not update ROA %r, skipping: %s" % (self, e))
      callback()
      return

    if self.roa is None:
      self.generate_roa(callback, lose)
      return

    ca_detail = self.ca_detail()

    if ca_detail is None or ca_detail.state != "active":
      self.regenerate_roa(callback, lose)
      return

    regen_margin = rpki.sundial.timedelta(seconds = self.self().regen_margin)

    if rpki.sundial.now() + regen_margin > self.cert.getNotAfter():
      self.regenerate_roa(callback, lose)
      return

    ca_resources = ca_detail.latest_ca_cert.get_3779resources()
    ee_resources = self.cert.get_3779resources()

    if ee_resources.oversized(ca_resources):
      self.regenerate_roa(callback, lose)
      return

    v4 = self.ipv4.to_resource_set() if self.ipv4 is not None else rpki.resource_set.resource_set_ipv4()
    v6 = self.ipv6.to_resource_set() if self.ipv6 is not None else rpki.resource_set.resource_set_ipv6()

    if ee_resources.v4 != v4 or ee_resources.v6 != v6:
      self.regenerate_roa(callback, lose)
      return

    callback()

  def generate_roa(self, callback, errback):
    """
    Generate a ROA based on this <route_origin/> object.

    At present this does not support ROAs with multiple signatures
    (neither does the current CMS code).

    At present we have no way of performing a direct lookup from a
    desired set of resources to a covering certificate, so we have to
    search.  This could be quite slow if we have a lot of active
    ca_detail objects.  Punt on the issue for now, revisit if
    profiling shows this as a hotspot.

    Once we have the right covering certificate, we generate the ROA
    payload, generate a new EE certificate, use the EE certificate to
    sign the ROA payload, publish the result, then throw away the
    private key for the EE cert, all per the ROA specification.  This
    implies that generating a lot of ROAs will tend to thrash
    /dev/random, but there is not much we can do about that.
    """

    if self.ipv4 is None and self.ipv6 is None:
      rpki.log.warn("Can't generate ROA for empty prefix list")
      return

    # Ugly and expensive search for covering ca_detail, there has to
    # be a better way, but it would require the ability to test for
    # resource subsets in SQL.

    v4 = self.ipv4.to_resource_set() if self.ipv4 is not None else rpki.resource_set.resource_set_ipv4()
    v6 = self.ipv6.to_resource_set() if self.ipv6 is not None else rpki.resource_set.resource_set_ipv6()

    ca_detail = self.ca_detail()
    if ca_detail is None or ca_detail.state != "active":
      ca_detail = None
      for parent in self.self().parents():
        for ca in parent.cas():
          ca_detail = ca.fetch_active()
          if ca_detail is not None:
            resources = ca_detail.latest_ca_cert.get_3779resources()
            if v4.issubset(resources.v4) and v6.issubset(resources.v6):
              break
            ca_detail = None
        if ca_detail is not None:
          break

    if ca_detail is None:
      rpki.log.warn("generate_roa() could not find a certificate covering %s %s" % (v4, v6))
      return

    ca = ca_detail.ca()

    resources = rpki.resource_set.resource_bag(v4 = v4, v6 = v6)

    keypair = rpki.x509.RSA.generate()

    sia = ((rpki.oids.name2oid["id-ad-signedObject"], ("uri", self.roa_uri(ca, keypair))),)

    self.cert = ca_detail.issue_ee(ca, resources, keypair.get_RSApublic(), sia = sia)
    self.roa = rpki.x509.ROA.build(self.as_number, self.ipv4, self.ipv6, keypair, (self.cert,))
    self.ca_detail_id = ca_detail.ca_detail_id
    self.sql_store()

    repository = ca.parent().repository()

    def one():
      repository.publish(self.cert, self.ee_uri(ca), two, errback)

    def two():
      ca_detail.generate_manifest(callback, errback)

    repository.publish(self.roa, self.roa_uri(ca),
                       one if self.publish_ee_separately else two,
                       errback)

  def withdraw_roa(self, callback, errback, regenerate = False):
    """
    Withdraw ROA associated with this route_origin.

    In order to preserve make-before-break properties without
    duplicating code, this method also handles generating a
    replacement ROA when requested.
    """

    ca_detail = self.ca_detail()
    ca = ca_detail.ca()
    repository = ca.parent().repository()
    cert = self.cert
    roa = self.roa
    roa_uri = self.roa_uri(ca)
    ee_uri = self.ee_uri(ca)

    if ca_detail.state != 'active':
      self.ca_detail_id = None

    def one():
      rpki.log.debug("Withdrawing ROA and revoking its EE cert")
      rpki.rpki_engine.revoked_cert_obj.revoke(cert = cert, ca_detail = ca_detail)
      repository.withdraw(roa, roa_uri,
                          two if self.publish_ee_separately else three,
                          errback)

    def two():
      repository.withdraw(cert, ee_uri, three, errback)

    def three():
      self.gctx.sql.sweep()
      ca_detail.generate_crl(four, errback)

    def four():
      ca_detail.generate_manifest(callback, errback)

    if regenerate:
      self.generate_roa(one, errback)
    else:
      one()

  def regenerate_roa(self, callback, errback):
    """
    Reissue ROA associated with this route_origin.
    """
    if self.ca_detail() is None:
      self.generate_roa(callback, errback)
    else:
      self.withdraw_roa(callback, errback, regenerate = True)

  def roa_uri(self, ca, key = None):
    """Return the publication URI for this route_origin's ROA."""
    return ca.sia_uri + self.roa_uri_tail(key)

  def roa_uri_tail(self, key = None):
    """Return the tail (filename portion) of the publication URI for this route_origin's ROA."""
    return (key or self.cert).gSKI() + ".roa"

  def ee_uri_tail(self):
    """Return the tail (filename) portion of the URI for this route_origin's ROA's EE certificate."""
    return self.cert.gSKI() + ".cer"

  def ee_uri(self, ca):
    """Return the publication URI for this route_origin's ROA's EE certificate."""
    return ca.sia_uri + self.ee_uri_tail()

class list_resources_elt(rpki.xml_utils.base_elt, left_right_namespace):
  """
  <list_resources/> element.
  """

  element_name = "list_resources"
  attributes = ("self_handle", "tag", "child_handle", "valid_until", "asn", "ipv4", "ipv6")
  valid_until = None

  def startElement(self, stack, name, attrs):
    """
    Handle <list_resources/> element.  This requires special handling
    due to the data types of some of the attributes.
    """
    assert name == "list_resources", "Unexpected name %s, stack %s" % (name, stack)
    self.read_attrs(attrs)
    if isinstance(self.valid_until, str):
      self.valid_until = rpki.sundial.datetime.fromXMLtime(self.valid_until)
    if self.asn is not None:
      self.asn = rpki.resource_set.resource_set_as(self.asn)
    if self.ipv4 is not None:
      self.ipv4 = rpki.resource_set.resource_set_ipv4(self.ipv4)
    if self.ipv6 is not None:
      self.ipv6 = rpki.resource_set.resource_set_ipv6(self.ipv6)

  def toXML(self):
    """
    Generate <list_resources/> element.  This requires special
    handling due to the data types of some of the attributes.
    """
    elt = self.make_elt()
    if isinstance(self.valid_until, int):
      elt.set("valid_until", self.valid_until.toXMLtime())
    return elt

class report_error_elt(rpki.xml_utils.base_elt, left_right_namespace):
  """
  <report_error/> element.
  """

  element_name = "report_error"
  attributes = ("tag", "self_handle", "error_code")

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

class msg(rpki.xml_utils.msg, left_right_namespace):
  """
  Left-right 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 (self_elt, child_elt, parent_elt, bsc_elt, repository_elt,
                        route_origin_elt, list_resources_elt, report_error_elt))

  def serve_top_level(self, gctx, cb):
    """
    Serve one msg PDU.
    """
    r_msg = self.__class__()
    r_msg.type = "reply"

    def loop(iterator, q_pdu):

      def fail(e):
        rpki.log.error(traceback.format_exc())
        r_msg.append(report_error_elt.from_exception(e, self_handle = q_pdu.self_handle))
        cb(r_msg)

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

    def done():
      cb(r_msg)

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

class sax_handler(rpki.xml_utils.sax_handler):
  """
  SAX handler for Left-Right protocol.
  """

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

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

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