# $Id$

"""RPKI "left-right" protocol."""

import base64, lxml.etree
import rpki.sax_utils, rpki.resource_set, rpki.x509, rpki.sql, rpki.exceptions, rpki.pkcs10, rpki.https

xmlns = "http://www.hactrn.net/uris/rpki/left-right-spec/"

nsmap = { None : xmlns }

class base_elt(object):
  """Virtual base type for left-right message elements."""

  attributes = ()
  elements = ()
  booleans = ()

  def startElement(self, stack, name, attrs):
    """Default startElement() handler: just process attributes."""
    self.read_attrs(attrs)

  def endElement(self, stack, name, text):
    """Default endElement() handler: just pop the stack."""
    stack.pop()

  def read_attrs(self, attrs):
    """Template-driven attribute reader."""
    for key in self.attributes:
      val = attrs.get(key, None)
      if isinstance(val, str) and val.isdigit():
        val = long(val)
      setattr(self, key, val)
    for key in self.booleans:
      setattr(self, key, attrs.get(key, False))

  def make_elt(self):
    """XML element constructor."""
    elt = lxml.etree.Element("{%s}%s" % (xmlns, self.element_name), nsmap=nsmap)
    for key in self.attributes:
      val = getattr(self, key, None)
      if val is not None:
        elt.set(key, str(val))
    for key in self.booleans:
      if getattr(self, key, False):
        elt.set(key, "yes")
    return elt

  def make_b64elt(self, elt, name, value=None):
    """Constructor for Base64-encoded subelement."""
    if value is None:
      value = getattr(self, name, None)
    if value is not None:
      lxml.etree.SubElement(elt, "{%s}%s" % (xmlns, name), nsmap=nsmap).text = base64.b64encode(value)

  def __str__(self):
    lxml.etree.tostring(self.toXML(), pretty_print=True, encoding="us-ascii")

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

  def sql_decode(self, vals):
    rpki.sql.sql_persistant.sql_decode(self, vals)
    if "peer_ta" in vals:
      self.peer_ta = rpki.x509.X509(DER=vals["peer_ta"])

  def sql_encode(self):
    d = rpki.sql.sql_persistant.sql_encode(self)
    if "peer_id" in d:
      d["peer_ta"] = self.peer_ta.get_DER()
    return d

  def make_reply(self, r_pdu=None):
    if r_pdu is None:
      r_pdu = self.__class__()
      r_pdu.self_id = self.self_id
      setattr(r_pdu, self.sql_template.index, getattr(self, self.sql_template.index))
    r_pdu.action = self.action
    r_pdu.type = "reply"
    return r_pdu

  def serve_pre_save_hook(self, q_pdu, r_pdu):
    pass

  def serve_post_save_hook(self, q_pdu, r_pdu):
    pass

  def serve_create(self, gctx, r_msg):
    r_pdu = self.make_reply()
    self.serve_pre_save_hook(self, r_pdu)
    self.sql_store(gctx.db, gctx.cur)
    setattr(r_pdu, self.sql_template.index, getattr(self, self.sql_template.index))
    self.serve_post_save_hook(self, r_pdu)
    r_msg.append(r_pdu)

  def serve_set(self, gctx, r_msg):
    db_pdu = self.sql_fetch(gctx.db, gctx.cur, getattr(self, self.sql_template.index))
    if db_pdu is not None:
      r_pdu = self.make_reply()
      for a in db_pdu.sql_template.columns[1:]:
        v = getattr(self, a)
        if v is not None:
          setattr(db_pdu, a, v)
      db_pdu.sql_dirty = True
      db_pdu.serve_pre_save_hook(self, r_pdu)
      db_pdu.sql_store(gctx.db, gctx.cur)
      db_pdu.serve_post_save_hook(self, r_pdu)
      r_msg.append(r_pdu)
    else:
      r_msg.append(make_error_report(self))

  def serve_get(self, gctx, r_msg):
    r_pdu = self.sql_fetch(gctx.db, gctx.cur, getattr(self, self.sql_template.index))
    if r_pdu is not None:
      self.make_reply(r_pdu)
      r_msg.append(r_pdu)
    else:
      r_msg.append(make_error_report(self))

  def serve_list(self, gctx, r_msg):
    for r_pdu in self.sql_fetch_all(gctx.db, gctx.cur):
      self.make_reply(r_pdu)
      r_msg.append(r_pdu)

  def serve_destroy(self, gctx, r_msg):
    db_pdu = self.sql_fetch(gctx.db, gctx.cur, getattr(self, self.sql_template.index))
    if db_pdu is not None:
      db_pdu.sql_delete(gctx.db, gctx.cur)
      r_msg.append(self.make_reply())
    else:
      r_msg.append(make_error_report(self))

  def serve_dispatch(self, gctx, r_msg):
    dispatch = { "create"  : self.serve_create,
                 "set"     : self.serve_set,
                 "get"     : self.serve_get,
                 "list"    : self.serve_list,
                 "destroy" : self.serve_destroy }
    if self.type != "query" or self.action not in dispatch:
      raise rpki.exceptions.BadQuery, "Unexpected query: type %s, action %s" % (self.type, self.action)
    dispatch[self.action](gctx, r_msg)
  
class extension_preference_elt(base_elt):
  """Container for extension preferences."""

  element_name = "extension_preference"
  attributes = ("name",)

  def startElement(self, stack, name, attrs):
    """Handle <extension_preference/> elements."""
    assert name == "extension_preference", "Unexpected name %s, stack %s" % (name, stack)
    self.read_attrs(attrs)

  def endElement(self, stack, name, text):
    """Handle <extension_preference/> elements."""
    self.value = text
    stack.pop()

  def toXML(self):
    """Generate <extension_preference/> elements."""
    elt = self.make_elt()
    elt.text = self.value
    return elt

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

  element_name = "self"
  attributes = ("action", "type", "self_id")
  elements = ("extension_preference",)
  booleans = ("rekey", "reissue", "revoke", "run_now", "publish_world_now", "clear_extension_preferences")

  sql_template = rpki.sql.template("self", "self_id", "use_hsm")

  self_id = None
  use_hsm = False

  def __init__(self):
    self.prefs = []

  def sql_fetch_hook(self, db, cur):
    cur.execute("SELECT pref_name, pref_value FROM self_pref WHERE self_id = %s", self.self_id)
    for name, value in cur.fetchall():
      e = extension_preference_elt()
      e.name = name
      e.value = value
      self.prefs.append(e)

  def sql_insert_hook(self, db, cur):
    if self.prefs:
      cur.executemany("INSERT self_pref (self_id, pref_name, pref_value) VALUES (%s, %s, %s)",
                      ((e.name, e.value, self.self_id) for e in self.prefs))
  
  def sql_delete_hook(self, db, cur):
    cur.execute("DELETE FROM self_pref WHERE self_id = %s", self.self_id)

  def serve_pre_save_hook(self, q_pdu, r_pdu):
    if self is not q_pdu:
      if q_pdu.clear_extension_preferences:
        self.prefs = []
      self.prefs.extend(pdu.prefs)

  def serve_post_save_hook(self, q_pdu, r_pdu):
    if self.rekey or self.reissue or self.revoke or self.run_now or self.publish_world_now:
      raise NotImplementedError

  def startElement(self, stack, name, attrs):
    """Handle <self/> element."""
    if name == "extension_preference":
      pref = extension_preference_elt()
      self.prefs.append(pref)
      stack.append(pref)
      pref.startElement(stack, name, attrs)
    else:
      assert name == "self", "Unexpected name %s, stack %s" % (name, stack)
      self.read_attrs(attrs)

  def endElement(self, stack, name, text):
    """Handle <self/> element."""
    assert name == "self", "Unexpected name %s, stack %s" % (name, stack)
    stack.pop()

  def toXML(self):
    """Generate <self/> element."""
    elt = self.make_elt()
    elt.extend([i.toXML() for i in self.prefs])
    return elt

class bsc_elt(data_elt):
  """<bsc/> (Business Signing Context) element."""
  
  element_name = "bsc"
  attributes = ("action", "type", "self_id", "bsc_id", "key_type", "hash_alg", "key_length")
  elements = ('signing_cert',)
  booleans = ("generate_keypair", "clear_signing_certs")

  sql_template = rpki.sql.template("bsc", "bsc_id", "self_id", "public_key", "private_key_id")

  pkcs10_cert_request = None
  public_key = None
  private_key_id = None

  def __init__(self):
    self.signing_cert = []

  def sql_fetch_hook(self, db, cur):
    cur.execute("SELECT cert FROM bsc_cert WHERE bsc_id = %s", self.bsc_id)
    self.signing_cert = [rpki.x509.X509(DER=x) for (x,) in cur.fetchall()]

  def sql_insert_hook(self, db, cur):
    if self.signing_cert:
      cur.executemany("INSERT bsc_cert (cert, bsc_id) VALUES (%s, %s)", ((x.get_DER(), self.bsc_id) for x in self.signing_cert))

  def sql_delete_hook(self, db, cur):
    cur.execute("DELETE FROM bsc_cert WHERE bsc_id = %s", self.bsc_id)

  def serve_pre_save_hook(self, q_pdu, r_pdu):
    if self is not q_pdu:
      if q_pdu.clear_signing_certs:
        self.signing_cert = []
      self.signing_cert.extend(q_pdu.signing_cert)
    if q_pdu.generate_keypair:
      #
      # Hard wire 2048-bit RSA with SHA-256 in schema for now.
      # Assume no HSM for now.
      #
      keypair = rpki.x509.RSA_Keypair()
      keypair.generate(2048)
      self.private_key_id = keypair.get_DER()
      self.public_key = keypair.get_public_DER()
      r_pdu.pkcs10_cert_request = rpki.pkcs10.make_request(keypair)

  def startElement(self, stack, name, attrs):
    """Handle <bsc/> element."""
    if not name in ("signing_cert", "public_key", "pkcs10_cert_request"):
      assert name == "bsc", "Unexpected name %s, stack %s" % (name, stack)
      self.read_attrs(attrs)

  def endElement(self, stack, name, text):
    """Handle <bsc/> element."""
    if name == "signing_cert":
      self.signing_cert.append(rpki.x509.X509(Base64=text))
    elif name == "public_key":
      self.public_key = base64.b64decode(text)
    elif name == "pkcs10_cert_request":
      self.pkcs10_cert_request = rpki.x509.PKCS10_Request(Base64=text)
    else:
      assert name == "bsc", "Unexpected name %s, stack %s" % (name, stack)
      stack.pop()

  def toXML(self):
    """Generate <bsc/> element."""
    elt = self.make_elt()
    for cert in self.signing_cert:
      self.make_b64elt(elt, "signing_cert", cert.get_DER())
    if self.pkcs10_cert_request is not None:
      self.make_b64elt(elt, "pkcs10_cert_request", self.pkcs10_cert_request.get_DER())
    self.make_b64elt(elt, "public_key")
    return elt

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

  element_name = "parent"
  attributes = ("action", "type", "self_id", "parent_id", "bsc_id", "repository_id", "peer_contact_uri", "sia_base")
  elements = ("peer_ta",)
  booleans = ("rekey", "reissue", "revoke")

  sql_template = rpki.sql.template("parent", "parent_id", "self_id", "bsc_id", "repository_id", "peer_ta", "peer_contact_uri", "sia_base")

  peer_ta = None

  def serve_post_save_hook(self, q_pdu, r_pdu):
    if self.rekey or self.reissue or self.revoke:
      raise NotImplementedError

  def startElement(self, stack, name, attrs):
    """Handle <bsc/> element."""
    if name != "peer_ta":
      assert name == "parent", "Unexpected name %s, stack %s" % (name, stack)
      self.read_attrs(attrs)

  def endElement(self, stack, name, text):
    """Handle <bsc/> element."""
    if name == "peer_ta":
      self.peer_ta = rpki.x509.X509(Base64=text)
    else:
      assert name == "parent", "Unexpected name %s, stack %s" % (name, stack)
      stack.pop()

  def toXML(self):
    """Generate <bsc/> element."""
    elt = self.make_elt()
    if self.peer_ta and not self.peer_ta.empty():
      self.make_b64elt(elt, "peer_ta", self.peer_ta.get_DER())
    return elt

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

  element_name = "child"
  attributes = ("action", "type", "self_id", "child_id", "bsc_id")
  elements = ("peer_ta",)
  booleans = ("reissue", )

  sql_template = rpki.sql.template("child", "child_id", "self_id", "bsc_id", "peer_ta")

  peer_ta = None

  def serve_post_save_hook(self, q_pdu, r_pdu):
    if self.reissue:
      raise NotImplementedError

  def startElement(self, stack, name, attrs):
    """Handle <child/> element."""
    if name != "peer_ta":
      assert name == "child", "Unexpected name %s, stack %s" % (name, stack)
      self.read_attrs(attrs)

  def endElement(self, stack, name, text):
    """Handle <child/> element."""
    if name == "peer_ta":
      self.peer_ta = rpki.x509.X509(Base64=text)
    else:
      assert name == "child", "Unexpected name %s, stack %s" % (name, stack)
      stack.pop()

  def toXML(self):
    """Generate <child/> element."""
    elt = self.make_elt()
    if self.peer_ta:
      self.make_b64elt(elt, "peer_ta", self.peer_ta.get_DER())
    return elt

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

  element_name = "repository"
  attributes = ("action", "type", "self_id", "repository_id", "bsc_id", "peer_contact_uri")
  elements = ("peer_ta",)

  sql_template = rpki.sql.template("repository", "repository_id", "self_id", "bsc_id", "peer_ta", "peer_contact_uri")

  peer_ta = None

  def startElement(self, stack, name, attrs):
    """Handle <repository/> element."""
    if name != "peer_ta":
      assert name == "repository", "Unexpected name %s, stack %s" % (name, stack)
      self.read_attrs(attrs)

  def endElement(self, stack, name, text):
    """Handle <repository/> element."""
    if name == "peer_ta":
      self.peer_ta = rpki.x509.X509(Base64=text)
    else:
      assert name == "repository", "Unexpected name %s, stack %s" % (name, stack)
      stack.pop()

  def toXML(self):
    """Generate <repository/> element."""
    elt = self.make_elt()
    if self.peer_ta:
      self.make_b64elt(elt, "peer_ta", self.peer_ta.get_DER())
    return elt

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

  element_name = "route_origin"
  attributes = ("action", "type", "self_id", "route_origin_id", "as_number", "ipv4", "ipv6")
  booleans = ("suppress_publication",)

  sql_template = rpki.sql.template("route_origin", "route_origin_id", "self_id", "as_number", "ca_detail_id", "roa")

  ca_detail_id = None
  roa = None

  def sql_fetch_hook(self, db, cur):
    self.ipv4 = rpki.resource_set.resource_set_ipv4.from_sql(cur,
                                                             "SELECT start_ip, end_ip FROM route_origin_range WHERE route_origin_id = %s AND start_ip NOT LIKE '%:%'",
                                                             self.route_origin_id)
    self.ipv6 = rpki.resource_set.resource_set_ipv6.from_sql(cur,
                                                             "SELECT start_ip, end_ip FROM route_origin_range WHERE route_origin_id = %s AND start_ip LIKE '%:%'",
                                                             self.route_origin_id)

  def sql_insert_hook(self, db, cur):
    if self.ipv4 + self.ipv6:
      cur.executemany("INSERT route_origin_range (route_origin_id, start_ip, end_ip) VALUES (%s, %s, %s)",
                      ((self.route_origin_id, x.min, x.max) for x in self.ipv4 + self.ipv6))
  
  def sql_delete_hook(self, db, cur):
    cur.execute("DELETE FROM route_origin_range WHERE route_origin_id = %s", self.route_origin_id)

  def serve_post_save_hook(self, q_pdu, r_pdu):
    if self.suppress_publication:
      raise NotImplementedError

  def startElement(self, stack, name, attrs):
    """Handle <route_origin/> element."""
    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.resource_set_ipv4(self.ipv4)
    if self.ipv6 is not None:
      self.ipv6 = rpki.resource_set.resource_set_ipv6(self.ipv4)

  def endElement(self, stack, name, text):
    """Handle <route_origin/> element."""
    assert name == "route_origin", "Unexpected name %s, stack %s" % (name, stack)
    stack.pop()

  def toXML(self):
    """Generate <route_origin/> element."""
    return self.make_elt()

class list_resources_elt(base_elt):
  """<list_resources/> element."""

  element_name = "list_resources"
  attributes = ("type", "self_id", "child_id", "valid_until", "as", "ipv4", "ipv6", "subject_name")

  def startElement(self, stack, name, attrs):
    """Handle <list_resources/> element."""
    assert name == "list_resources", "Unexpected name %s, stack %s" % (name, stack)
    self.read_attrs(attrs)
    if self.as is not None:
      self.as = rpki.resource_set.resource_set_as(self.as)
    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."""
    return self.make_elt()

class report_error_elt(base_elt):
  """<report_error/> element."""

  element_name = "report_error"
  attributes = ("self_id", "error_code")

  def startElement(self, stack, name, attrs):
    """Handle <report_error/> element."""
    assert name == self.element_name, "Unexpected name %s, stack %s" % (name, stack)
    self.read_attrs(attrs)

  def toXML(self):
    """Generate <report_error/> element."""
    return self.make_elt()

class msg(list):
  """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 startElement(self, stack, name, attrs):
    """Handle left-right PDU."""
    if name == "msg":
      assert self.version == int(attrs["version"])
    else:
      elt = self.pdus[name]()
      self.append(elt)
      stack.append(elt)
      elt.startElement(stack, name, attrs)

  def endElement(self, stack, name, text):
    """Handle left-right PDU."""
    assert name == "msg", "Unexpected name %s, stack %s" % (name, stack)
    assert len(stack) == 1
    stack.pop()

  def __str__(self):
    lxml.etree.tostring(self.toXML(), pretty_print=True, encoding="us-ascii")

  def toXML(self):
    """Generate left-right PDU."""
    elt = lxml.etree.Element("{%s}msg" % (xmlns), nsmap=nsmap, version=str(self.version))
    elt.extend([i.toXML() for i in self])
    return elt

  def serve_top_level(self, gctx):
    r_msg = self.__class__()
    for q_pdu in self:
      q_pdu.serve_dispatch(gctx, r_msg)
    return r_msg

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

  ## @var pdu
  # Top-level PDU class
  pdu = msg

  def create_top_level(self, name, attrs):
    """Top-level PDU for this protocol is <msg/>."""
    assert name == "msg" and attrs["version"] == "1"
    return self.pdu()

def irdb_query(gctx, self_id, child_id=None):
  """Perform an IRDB callback query.

  In the long run this should not be a blocking routine, it should
  instead issue a query and set up a handler to receive the response.
  For the moment, though, we're doing simple lock step and damn the
  torpedos.

  Not yet doing anything useful with validity interval or subject
  name.  Most likely this function should really be wrapped up in a
  class that carries both the query result and also the intermediate state
  needed for the event-driven code that this function will need to become.
  """

  q_msg = msg_elt()
  q_msg.append(list_resources_elt())
  q_msg[0].type = "query"
  q_msg[0].self_id = self_id
  q_msg[0].child_id = child_id
  q_elt = q_msg.toXML()
  rpki.relaxng.left_right.assertValid(q_elt)
  q_cms = rpki.cms.xml_encode(q_elt, gctx.cms_key, gctx.cms_certs)
  r_cms = rpki.https.client(privateKey    = gctx.https_key,
                            certChain     = gctx.https_certs,
                            x509TrustList = gctx.https_tas,
                            host          = gctx.irdb_host,
                            port          = gctx.irdb_port,
                            url           = gctx.irdb_url,
                            msg           = q_cms)
  r_elt = rpki.cms.xml_decode(r_cms, gctx.cms_ta_irbe)
  rpki.relaxng.left_right.assertValid(r_elt)
  r_msg = rpki.left_right.sax_handler.saxify(r_elt)
  if len(r_msg) != 0 or not isinstance(r_msg[0], list_resources_elt) or r_msg[0].type != "reply":
    raise rpki.exceptions.BadIRDBReply, "Unexpected response to IRDB query: %s" % r_msg.toXML()
  return r_msg[0].as, r_msg[0].ipv4, r_msg[0].ipv6