# -*- coding: utf-8 -*- # Copyright 2015, 2016 OpenMarket Ltd # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import copy import itertools import logging from typing import ( Any, Awaitable, Callable, Dict, Iterable, List, Optional, Sequence, Tuple, TypeVar, ) from prometheus_client import Counter from twisted.internet import defer from synapse.api.constants import EventTypes, Membership from synapse.api.errors import ( CodeMessageException, Codes, FederationDeniedError, HttpResponseException, SynapseError, UnsupportedRoomVersionError, ) from synapse.api.room_versions import ( KNOWN_ROOM_VERSIONS, EventFormatVersions, RoomVersion, RoomVersions, ) from synapse.events import EventBase, builder, room_version_to_event_format from synapse.federation.federation_base import FederationBase, event_from_pdu_json from synapse.logging.context import make_deferred_yieldable from synapse.logging.utils import log_function from synapse.util import unwrapFirstError from synapse.util.caches.expiringcache import ExpiringCache from synapse.util.retryutils import NotRetryingDestination logger = logging.getLogger(__name__) sent_queries_counter = Counter("synapse_federation_client_sent_queries", "", ["type"]) PDU_RETRY_TIME_MS = 1 * 60 * 1000 T = TypeVar("T") class InvalidResponseError(RuntimeError): """Helper for _try_destination_list: indicates that the server returned a response we couldn't parse """ pass class FederationClient(FederationBase): def __init__(self, hs): super(FederationClient, self).__init__(hs) self.pdu_destination_tried = {} self._clock.looping_call(self._clear_tried_cache, 60 * 1000) self.state = hs.get_state_handler() self.transport_layer = hs.get_federation_transport_client() self.hostname = hs.hostname self.signing_key = hs.config.signing_key[0] self._get_pdu_cache = ExpiringCache( cache_name="get_pdu_cache", clock=self._clock, max_len=1000, expiry_ms=120 * 1000, reset_expiry_on_get=False, ) def _clear_tried_cache(self): """Clear pdu_destination_tried cache""" now = self._clock.time_msec() old_dict = self.pdu_destination_tried self.pdu_destination_tried = {} for event_id, destination_dict in old_dict.items(): destination_dict = { dest: time for dest, time in destination_dict.items() if time + PDU_RETRY_TIME_MS > now } if destination_dict: self.pdu_destination_tried[event_id] = destination_dict @log_function def make_query( self, destination, query_type, args, retry_on_dns_fail=False, ignore_backoff=False, ): """Sends a federation Query to a remote homeserver of the given type and arguments. Args: destination (str): Domain name of the remote homeserver query_type (str): Category of the query type; should match the handler name used in register_query_handler(). args (dict): Mapping of strings to strings containing the details of the query request. ignore_backoff (bool): true to ignore the historical backoff data and try the request anyway. Returns: a Deferred which will eventually yield a JSON object from the response """ sent_queries_counter.labels(query_type).inc() return self.transport_layer.make_query( destination, query_type, args, retry_on_dns_fail=retry_on_dns_fail, ignore_backoff=ignore_backoff, ) @log_function def query_client_keys(self, destination, content, timeout): """Query device keys for a device hosted on a remote server. Args: destination (str): Domain name of the remote homeserver content (dict): The query content. Returns: a Deferred which will eventually yield a JSON object from the response """ sent_queries_counter.labels("client_device_keys").inc() return self.transport_layer.query_client_keys(destination, content, timeout) @log_function def query_user_devices(self, destination, user_id, timeout=30000): """Query the device keys for a list of user ids hosted on a remote server. """ sent_queries_counter.labels("user_devices").inc() return self.transport_layer.query_user_devices(destination, user_id, timeout) @log_function def claim_client_keys(self, destination, content, timeout): """Claims one-time keys for a device hosted on a remote server. Args: destination (str): Domain name of the remote homeserver content (dict): The query content. Returns: a Deferred which will eventually yield a JSON object from the response """ sent_queries_counter.labels("client_one_time_keys").inc() return self.transport_layer.claim_client_keys(destination, content, timeout) async def backfill( self, dest: str, room_id: str, limit: int, extremities: Iterable[str] ) -> List[EventBase]: """Requests some more historic PDUs for the given room from the given destination server. Args: dest (str): The remote homeserver to ask. room_id (str): The room_id to backfill. limit (int): The maximum number of events to return. extremities (list): our current backwards extremities, to backfill from """ logger.debug("backfill extrem=%s", extremities) # If there are no extremeties then we've (probably) reached the start. if not extremities: return transaction_data = await self.transport_layer.backfill( dest, room_id, extremities, limit ) logger.debug("backfill transaction_data=%r", transaction_data) room_version = await self.store.get_room_version_id(room_id) format_ver = room_version_to_event_format(room_version) pdus = [ event_from_pdu_json(p, format_ver, outlier=False) for p in transaction_data["pdus"] ] # FIXME: We should handle signature failures more gracefully. pdus[:] = await make_deferred_yieldable( defer.gatherResults( self._check_sigs_and_hashes(room_version, pdus), consumeErrors=True ).addErrback(unwrapFirstError) ) return pdus async def get_pdu( self, destinations: Iterable[str], event_id: str, room_version: str, outlier: bool = False, timeout: Optional[int] = None, ) -> Optional[EventBase]: """Requests the PDU with given origin and ID from the remote home servers. Will attempt to get the PDU from each destination in the list until one succeeds. Args: destinations: Which homeservers to query event_id: event to fetch room_version: version of the room outlier: Indicates whether the PDU is an `outlier`, i.e. if it's from an arbitary point in the context as opposed to part of the current block of PDUs. Defaults to `False` timeout: How long to try (in ms) each destination for before moving to the next destination. None indicates no timeout. Returns: The requested PDU, or None if we were unable to find it. """ # TODO: Rate limit the number of times we try and get the same event. ev = self._get_pdu_cache.get(event_id) if ev: return ev pdu_attempts = self.pdu_destination_tried.setdefault(event_id, {}) format_ver = room_version_to_event_format(room_version) signed_pdu = None for destination in destinations: now = self._clock.time_msec() last_attempt = pdu_attempts.get(destination, 0) if last_attempt + PDU_RETRY_TIME_MS > now: continue try: transaction_data = await self.transport_layer.get_event( destination, event_id, timeout=timeout ) logger.debug( "retrieved event id %s from %s: %r", event_id, destination, transaction_data, ) pdu_list = [ event_from_pdu_json(p, format_ver, outlier=outlier) for p in transaction_data["pdus"] ] if pdu_list and pdu_list[0]: pdu = pdu_list[0] # Check signatures are correct. signed_pdu = await self._check_sigs_and_hash(room_version, pdu) break pdu_attempts[destination] = now except SynapseError as e: logger.info( "Failed to get PDU %s from %s because %s", event_id, destination, e ) continue except NotRetryingDestination as e: logger.info(str(e)) continue except FederationDeniedError as e: logger.info(str(e)) continue except Exception as e: pdu_attempts[destination] = now logger.info( "Failed to get PDU %s from %s because %s", event_id, destination, e ) continue if signed_pdu: self._get_pdu_cache[event_id] = signed_pdu return signed_pdu async def get_room_state_ids( self, destination: str, room_id: str, event_id: str ) -> Tuple[List[str], List[str]]: """Calls the /state_ids endpoint to fetch the state at a particular point in the room, and the auth events for the given event Returns: a tuple of (state event_ids, auth event_ids) """ result = await self.transport_layer.get_room_state_ids( destination, room_id, event_id=event_id ) state_event_ids = result["pdu_ids"] auth_event_ids = result.get("auth_chain_ids", []) if not isinstance(state_event_ids, list) or not isinstance( auth_event_ids, list ): raise Exception("invalid response from /state_ids") return state_event_ids, auth_event_ids async def get_event_auth(self, destination, room_id, event_id): res = await self.transport_layer.get_event_auth(destination, room_id, event_id) room_version = await self.store.get_room_version_id(room_id) format_ver = room_version_to_event_format(room_version) auth_chain = [ event_from_pdu_json(p, format_ver, outlier=True) for p in res["auth_chain"] ] signed_auth = await self._check_sigs_and_hash_and_fetch( destination, auth_chain, outlier=True, room_version=room_version ) signed_auth.sort(key=lambda e: e.depth) return signed_auth async def _try_destination_list( self, description: str, destinations: Iterable[str], callback: Callable[[str], Awaitable[T]], ) -> T: """Try an operation on a series of servers, until it succeeds Args: description: description of the operation we're doing, for logging destinations: list of server_names to try callback: Function to run for each server. Passed a single argument: the server_name to try. If the callback raises a CodeMessageException with a 300/400 code, attempts to perform the operation stop immediately and the exception is reraised. Otherwise, if the callback raises an Exception the error is logged and the next server tried. Normally the stacktrace is logged but this is suppressed if the exception is an InvalidResponseError. Returns: The result of callback, if it succeeds Raises: SynapseError if the chosen remote server returns a 300/400 code, or no servers were reachable. """ for destination in destinations: if destination == self.server_name: continue try: res = await callback(destination) return res except InvalidResponseError as e: logger.warning("Failed to %s via %s: %s", description, destination, e) except UnsupportedRoomVersionError: raise except HttpResponseException as e: if not 500 <= e.code < 600: raise e.to_synapse_error() else: logger.warning( "Failed to %s via %s: %i %s", description, destination, e.code, e.args[0], ) except Exception: logger.warning( "Failed to %s via %s", description, destination, exc_info=True ) raise SynapseError(502, "Failed to %s via any server" % (description,)) async def make_membership_event( self, destinations: Iterable[str], room_id: str, user_id: str, membership: str, content: dict, params: Dict[str, str], ) -> Tuple[str, EventBase, RoomVersion]: """ Creates an m.room.member event, with context, without participating in the room. Does so by asking one of the already participating servers to create an event with proper context. Returns a fully signed and hashed event. Note that this does not append any events to any graphs. Args: destinations: Candidate homeservers which are probably participating in the room. room_id: The room in which the event will happen. user_id: The user whose membership is being evented. membership: The "membership" property of the event. Must be one of "join" or "leave". content: Any additional data to put into the content field of the event. params: Query parameters to include in the request. Returns: `(origin, event, room_version)` where origin is the remote homeserver which generated the event, and room_version is the version of the room. Raises: UnsupportedRoomVersionError: if remote responds with a room version we don't understand. SynapseError: if the chosen remote server returns a 300/400 code. RuntimeError: if no servers were reachable. """ valid_memberships = {Membership.JOIN, Membership.LEAVE} if membership not in valid_memberships: raise RuntimeError( "make_membership_event called with membership='%s', must be one of %s" % (membership, ",".join(valid_memberships)) ) async def send_request(destination: str) -> Tuple[str, EventBase, RoomVersion]: ret = await self.transport_layer.make_membership_event( destination, room_id, user_id, membership, params ) # Note: If not supplied, the room version may be either v1 or v2, # however either way the event format version will be v1. room_version_id = ret.get("room_version", RoomVersions.V1.identifier) room_version = KNOWN_ROOM_VERSIONS.get(room_version_id) if not room_version: raise UnsupportedRoomVersionError() pdu_dict = ret.get("event", None) if not isinstance(pdu_dict, dict): raise InvalidResponseError("Bad 'event' field in response") logger.debug("Got response to make_%s: %s", membership, pdu_dict) pdu_dict["content"].update(content) # The protoevent received over the JSON wire may not have all # the required fields. Lets just gloss over that because # there's some we never care about if "prev_state" not in pdu_dict: pdu_dict["prev_state"] = [] ev = builder.create_local_event_from_event_dict( self._clock, self.hostname, self.signing_key, room_version=room_version, event_dict=pdu_dict, ) return destination, ev, room_version return await self._try_destination_list( "make_" + membership, destinations, send_request ) async def send_join( self, destinations: Iterable[str], pdu: EventBase, event_format_version: int ) -> Dict[str, Any]: """Sends a join event to one of a list of homeservers. Doing so will cause the remote server to add the event to the graph, and send the event out to the rest of the federation. Args: destinations: Candidate homeservers which are probably participating in the room. pdu: event to be sent event_format_version: The event format version Returns: a dict with members ``origin`` (a string giving the serer the event was sent to, ``state`` (?) and ``auth_chain``. Raises: SynapseError: if the chosen remote server returns a 300/400 code. RuntimeError: if no servers were reachable. """ def check_authchain_validity(signed_auth_chain): for e in signed_auth_chain: if e.type == EventTypes.Create: create_event = e break else: raise InvalidResponseError("no %s in auth chain" % (EventTypes.Create,)) # the room version should be sane. room_version = create_event.content.get("room_version", "1") if room_version not in KNOWN_ROOM_VERSIONS: # This shouldn't be possible, because the remote server should have # rejected the join attempt during make_join. raise InvalidResponseError( "room appears to have unsupported version %s" % (room_version,) ) async def send_request(destination) -> Dict[str, Any]: content = await self._do_send_join(destination, pdu) logger.debug("Got content: %s", content) state = [ event_from_pdu_json(p, event_format_version, outlier=True) for p in content.get("state", []) ] auth_chain = [ event_from_pdu_json(p, event_format_version, outlier=True) for p in content.get("auth_chain", []) ] pdus = {p.event_id: p for p in itertools.chain(state, auth_chain)} room_version = None for e in state: if (e.type, e.state_key) == (EventTypes.Create, ""): room_version = e.content.get( "room_version", RoomVersions.V1.identifier ) break if room_version is None: # If the state doesn't have a create event then the room is # invalid, and it would fail auth checks anyway. raise SynapseError(400, "No create event in state") valid_pdus = await self._check_sigs_and_hash_and_fetch( destination, list(pdus.values()), outlier=True, room_version=room_version, ) valid_pdus_map = {p.event_id: p for p in valid_pdus} # NB: We *need* to copy to ensure that we don't have multiple # references being passed on, as that causes... issues. signed_state = [ copy.copy(valid_pdus_map[p.event_id]) for p in state if p.event_id in valid_pdus_map ] signed_auth = [ valid_pdus_map[p.event_id] for p in auth_chain if p.event_id in valid_pdus_map ] # NB: We *need* to copy to ensure that we don't have multiple # references being passed on, as that causes... issues. for s in signed_state: s.internal_metadata = copy.deepcopy(s.internal_metadata) check_authchain_validity(signed_auth) return { "state": signed_state, "auth_chain": signed_auth, "origin": destination, } return await self._try_destination_list("send_join", destinations, send_request) async def _do_send_join(self, destination: str, pdu: EventBase): time_now = self._clock.time_msec() try: content = await self.transport_layer.send_join_v2( destination=destination, room_id=pdu.room_id, event_id=pdu.event_id, content=pdu.get_pdu_json(time_now), ) return content except HttpResponseException as e: if e.code in [400, 404]: err = e.to_synapse_error() # If we receive an error response that isn't a generic error, or an # unrecognised endpoint error, we assume that the remote understands # the v2 invite API and this is a legitimate error. if err.errcode not in [Codes.UNKNOWN, Codes.UNRECOGNIZED]: raise err else: raise e.to_synapse_error() logger.debug("Couldn't send_join with the v2 API, falling back to the v1 API") resp = await self.transport_layer.send_join_v1( destination=destination, room_id=pdu.room_id, event_id=pdu.event_id, content=pdu.get_pdu_json(time_now), ) # We expect the v1 API to respond with [200, content], so we only return the # content. return resp[1] @defer.inlineCallbacks def send_invite(self, destination, room_id, event_id, pdu): room_version = yield self.store.get_room_version_id(room_id) content = yield self._do_send_invite(destination, pdu, room_version) pdu_dict = content["event"] logger.debug("Got response to send_invite: %s", pdu_dict) room_version = yield self.store.get_room_version_id(room_id) format_ver = room_version_to_event_format(room_version) pdu = event_from_pdu_json(pdu_dict, format_ver) # Check signatures are correct. pdu = yield self._check_sigs_and_hash(room_version, pdu) # FIXME: We should handle signature failures more gracefully. return pdu @defer.inlineCallbacks def _do_send_invite(self, destination, pdu, room_version): """Actually sends the invite, first trying v2 API and falling back to v1 API if necessary. Args: destination (str): Target server pdu (FrozenEvent) room_version (str) Returns: dict: The event as a dict as returned by the remote server """ time_now = self._clock.time_msec() try: content = yield self.transport_layer.send_invite_v2( destination=destination, room_id=pdu.room_id, event_id=pdu.event_id, content={ "event": pdu.get_pdu_json(time_now), "room_version": room_version, "invite_room_state": pdu.unsigned.get("invite_room_state", []), }, ) return content except HttpResponseException as e: if e.code in [400, 404]: err = e.to_synapse_error() # If we receive an error response that isn't a generic error, we # assume that the remote understands the v2 invite API and this # is a legitimate error. if err.errcode != Codes.UNKNOWN: raise err # Otherwise, we assume that the remote server doesn't understand # the v2 invite API. That's ok provided the room uses old-style event # IDs. v = KNOWN_ROOM_VERSIONS.get(room_version) if v.event_format != EventFormatVersions.V1: raise SynapseError( 400, "User's homeserver does not support this room version", Codes.UNSUPPORTED_ROOM_VERSION, ) elif e.code == 403: raise e.to_synapse_error() else: raise # Didn't work, try v1 API. # Note the v1 API returns a tuple of `(200, content)` _, content = yield self.transport_layer.send_invite_v1( destination=destination, room_id=pdu.room_id, event_id=pdu.event_id, content=pdu.get_pdu_json(time_now), ) return content async def send_leave(self, destinations: Iterable[str], pdu: EventBase) -> None: """Sends a leave event to one of a list of homeservers. Doing so will cause the remote server to add the event to the graph, and send the event out to the rest of the federation. This is mostly useful to reject received invites. Args: destinations: Candidate homeservers which are probably participating in the room. pdu: event to be sent Raises: SynapseError if the chosen remote server returns a 300/400 code. RuntimeError if no servers were reachable. """ async def send_request(destination: str) -> None: content = await self._do_send_leave(destination, pdu) logger.debug("Got content: %s", content) return await self._try_destination_list( "send_leave", destinations, send_request ) async def _do_send_leave(self, destination, pdu): time_now = self._clock.time_msec() try: content = await self.transport_layer.send_leave_v2( destination=destination, room_id=pdu.room_id, event_id=pdu.event_id, content=pdu.get_pdu_json(time_now), ) return content except HttpResponseException as e: if e.code in [400, 404]: err = e.to_synapse_error() # If we receive an error response that isn't a generic error, or an # unrecognised endpoint error, we assume that the remote understands # the v2 invite API and this is a legitimate error. if err.errcode not in [Codes.UNKNOWN, Codes.UNRECOGNIZED]: raise err else: raise e.to_synapse_error() logger.debug("Couldn't send_leave with the v2 API, falling back to the v1 API") resp = await self.transport_layer.send_leave_v1( destination=destination, room_id=pdu.room_id, event_id=pdu.event_id, content=pdu.get_pdu_json(time_now), ) # We expect the v1 API to respond with [200, content], so we only return the # content. return resp[1] def get_public_rooms( self, destination, limit=None, since_token=None, search_filter=None, include_all_networks=False, third_party_instance_id=None, ): if destination == self.server_name: return return self.transport_layer.get_public_rooms( destination, limit, since_token, search_filter, include_all_networks=include_all_networks, third_party_instance_id=third_party_instance_id, ) async def get_missing_events( self, destination: str, room_id: str, earliest_events_ids: Sequence[str], latest_events: Iterable[EventBase], limit: int, min_depth: int, timeout: int, ) -> List[EventBase]: """Tries to fetch events we are missing. This is called when we receive an event without having received all of its ancestors. Args: destination room_id earliest_events_ids: List of event ids. Effectively the events we expected to receive, but haven't. `get_missing_events` should only return events that didn't happen before these. latest_events: List of events we have received that we don't have all previous events for. limit: Maximum number of events to return. min_depth: Minimum depth of events to return. timeout: Max time to wait in ms """ try: content = await self.transport_layer.get_missing_events( destination=destination, room_id=room_id, earliest_events=earliest_events_ids, latest_events=[e.event_id for e in latest_events], limit=limit, min_depth=min_depth, timeout=timeout, ) room_version = await self.store.get_room_version_id(room_id) format_ver = room_version_to_event_format(room_version) events = [ event_from_pdu_json(e, format_ver) for e in content.get("events", []) ] signed_events = await self._check_sigs_and_hash_and_fetch( destination, events, outlier=False, room_version=room_version ) except HttpResponseException as e: if not e.code == 400: raise # We are probably hitting an old server that doesn't support # get_missing_events signed_events = [] return signed_events @defer.inlineCallbacks def forward_third_party_invite(self, destinations, room_id, event_dict): for destination in destinations: if destination == self.server_name: continue try: yield self.transport_layer.exchange_third_party_invite( destination=destination, room_id=room_id, event_dict=event_dict ) return None except CodeMessageException: raise except Exception as e: logger.exception( "Failed to send_third_party_invite via %s: %s", destination, str(e) ) raise RuntimeError("Failed to send to any server.") @defer.inlineCallbacks def get_room_complexity(self, destination, room_id): """ Fetch the complexity of a remote room from another server. Args: destination (str): The remote server room_id (str): The room ID to ask about. Returns: Deferred[dict] or Deferred[None]: Dict contains the complexity metric versions, while None means we could not fetch the complexity. """ try: complexity = yield self.transport_layer.get_room_complexity( destination=destination, room_id=room_id ) defer.returnValue(complexity) except CodeMessageException as e: # We didn't manage to get it -- probably a 404. We are okay if other # servers don't give it to us. logger.debug( "Failed to fetch room complexity via %s for %s, got a %d", destination, room_id, e.code, ) except Exception: logger.exception( "Failed to fetch room complexity via %s for %s", destination, room_id ) # If we don't manage to find it, return None. It's not an error if a # server doesn't give it to us. defer.returnValue(None)