# -*- 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 import random from six.moves import range from prometheus_client import Counter from twisted.internet import defer from synapse.api.constants import KNOWN_ROOM_VERSIONS, EventTypes, Membership from synapse.api.errors import ( CodeMessageException, FederationDeniedError, HttpResponseException, SynapseError, ) from synapse.crypto.event_signing import add_hashes_and_signatures from synapse.federation.federation_base import FederationBase, event_from_pdu_json from synapse.util import logcontext, unwrapFirstError from synapse.util.caches.expiringcache import ExpiringCache from synapse.util.logcontext import make_deferred_yieldable, run_in_background from synapse.util.logutils import log_function 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 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.event_builder_factory = hs.get_event_builder_factory() 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 ) @defer.inlineCallbacks @log_function def backfill(self, dest, context, limit, extremities): """Requests some more historic PDUs for the given context from the given destination server. Args: dest (str): The remote home server to ask. context (str): The context to backfill. limit (int): The maximum number of PDUs to return. extremities (list): List of PDU id and origins of the first pdus we have seen from the context Returns: Deferred: Results in the received PDUs. """ logger.debug("backfill extrem=%s", extremities) # If there are no extremeties then we've (probably) reached the start. if not extremities: return transaction_data = yield self.transport_layer.backfill( dest, context, extremities, limit) logger.debug("backfill transaction_data=%s", repr(transaction_data)) pdus = [ event_from_pdu_json(p, outlier=False) for p in transaction_data["pdus"] ] # FIXME: We should handle signature failures more gracefully. pdus[:] = yield logcontext.make_deferred_yieldable(defer.gatherResults( self._check_sigs_and_hashes(pdus), consumeErrors=True, ).addErrback(unwrapFirstError)) defer.returnValue(pdus) @defer.inlineCallbacks @log_function def get_pdu(self, destinations, event_id, outlier=False, timeout=None): """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 (list): Which home servers to query event_id (str): event to fetch outlier (bool): 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 (int): How long to try (in ms) each destination for before moving to the next destination. None indicates no timeout. Returns: Deferred: Results in the requested PDU. """ # TODO: Rate limit the number of times we try and get the same event. ev = self._get_pdu_cache.get(event_id) if ev: defer.returnValue(ev) pdu_attempts = self.pdu_destination_tried.setdefault(event_id, {}) 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 = yield self.transport_layer.get_event( destination, event_id, timeout=timeout, ) logger.debug("transaction_data %r", transaction_data) pdu_list = [ event_from_pdu_json(p, 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 = yield self._check_sigs_and_hash(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, ) 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 defer.returnValue(signed_pdu) @defer.inlineCallbacks @log_function def get_state_for_room(self, destination, room_id, event_id): """Requests all of the room state at a given event from a remote home server. Args: destination (str): The remote homeserver to query for the state. room_id (str): The id of the room we're interested in. event_id (str): The id of the event we want the state at. Returns: Deferred[Tuple[List[EventBase], List[EventBase]]]: A list of events in the state, and a list of events in the auth chain for the given event. """ try: # First we try and ask for just the IDs, as thats far quicker if # we have most of the state and auth_chain already. # However, this may 404 if the other side has an old synapse. result = yield 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", []) fetched_events, failed_to_fetch = yield self.get_events( [destination], room_id, set(state_event_ids + auth_event_ids) ) if failed_to_fetch: logger.warn("Failed to get %r", failed_to_fetch) event_map = { ev.event_id: ev for ev in fetched_events } pdus = [event_map[e_id] for e_id in state_event_ids if e_id in event_map] auth_chain = [ event_map[e_id] for e_id in auth_event_ids if e_id in event_map ] auth_chain.sort(key=lambda e: e.depth) defer.returnValue((pdus, auth_chain)) except HttpResponseException as e: if e.code == 400 or e.code == 404: logger.info("Failed to use get_room_state_ids API, falling back") else: raise e result = yield self.transport_layer.get_room_state( destination, room_id, event_id=event_id, ) pdus = [ event_from_pdu_json(p, outlier=True) for p in result["pdus"] ] auth_chain = [ event_from_pdu_json(p, outlier=True) for p in result.get("auth_chain", []) ] seen_events = yield self.store.get_events([ ev.event_id for ev in itertools.chain(pdus, auth_chain) ]) signed_pdus = yield self._check_sigs_and_hash_and_fetch( destination, [p for p in pdus if p.event_id not in seen_events], outlier=True ) signed_pdus.extend( seen_events[p.event_id] for p in pdus if p.event_id in seen_events ) signed_auth = yield self._check_sigs_and_hash_and_fetch( destination, [p for p in auth_chain if p.event_id not in seen_events], outlier=True ) signed_auth.extend( seen_events[p.event_id] for p in auth_chain if p.event_id in seen_events ) signed_auth.sort(key=lambda e: e.depth) defer.returnValue((signed_pdus, signed_auth)) @defer.inlineCallbacks def get_events(self, destinations, room_id, event_ids, return_local=True): """Fetch events from some remote destinations, checking if we already have them. Args: destinations (list) room_id (str) event_ids (list) return_local (bool): Whether to include events we already have in the DB in the returned list of events Returns: Deferred: A deferred resolving to a 2-tuple where the first is a list of events and the second is a list of event ids that we failed to fetch. """ if return_local: seen_events = yield self.store.get_events(event_ids, allow_rejected=True) signed_events = list(seen_events.values()) else: seen_events = yield self.store.have_seen_events(event_ids) signed_events = [] failed_to_fetch = set() missing_events = set(event_ids) for k in seen_events: missing_events.discard(k) if not missing_events: defer.returnValue((signed_events, failed_to_fetch)) def random_server_list(): srvs = list(destinations) random.shuffle(srvs) return srvs batch_size = 20 missing_events = list(missing_events) for i in range(0, len(missing_events), batch_size): batch = set(missing_events[i:i + batch_size]) deferreds = [ run_in_background( self.get_pdu, destinations=random_server_list(), event_id=e_id, ) for e_id in batch ] res = yield make_deferred_yieldable( defer.DeferredList(deferreds, consumeErrors=True) ) for success, result in res: if success and result: signed_events.append(result) batch.discard(result.event_id) # We removed all events we successfully fetched from `batch` failed_to_fetch.update(batch) defer.returnValue((signed_events, failed_to_fetch)) @defer.inlineCallbacks @log_function def get_event_auth(self, destination, room_id, event_id): res = yield self.transport_layer.get_event_auth( destination, room_id, event_id, ) auth_chain = [ event_from_pdu_json(p, outlier=True) for p in res["auth_chain"] ] signed_auth = yield self._check_sigs_and_hash_and_fetch( destination, auth_chain, outlier=True ) signed_auth.sort(key=lambda e: e.depth) defer.returnValue(signed_auth) @defer.inlineCallbacks def _try_destination_list(self, description, destinations, callback): """Try an operation on a series of servers, until it succeeds Args: description (unicode): description of the operation we're doing, for logging destinations (Iterable[unicode]): list of server_names to try callback (callable): Function to run for each server. Passed a single argument: the server_name to try. May return a deferred. 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 [Deferred] result of callback, if it succeeds Raises: SynapseError if the chosen remote server returns a 300/400 code. RuntimeError if no servers were reachable. """ for destination in destinations: if destination == self.server_name: continue try: res = yield callback(destination) defer.returnValue(res) except InvalidResponseError as e: logger.warn( "Failed to %s via %s: %s", description, destination, e, ) except HttpResponseException as e: if not 500 <= e.code < 600: raise e.to_synapse_error() else: logger.warn( "Failed to %s via %s: %i %s", description, destination, e.code, e.args[0], ) except Exception: logger.warn( "Failed to %s via %s", description, destination, exc_info=1, ) raise RuntimeError("Failed to %s via any server" % (description, )) def make_membership_event(self, destinations, room_id, user_id, membership, content, params): """ 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 (str): Candidate homeservers which are probably participating in the room. room_id (str): The room in which the event will happen. user_id (str): The user whose membership is being evented. membership (str): The "membership" property of the event. Must be one of "join" or "leave". content (dict): Any additional data to put into the content field of the event. params (dict[str, str|Iterable[str]]): Query parameters to include in the request. Return: Deferred[tuple[str, FrozenEvent]]: resolves to a tuple of `origin` and event where origin is the remote homeserver which generated the event. Fails with a ``SynapseError`` if the chosen remote server returns a 300/400 code. Fails with a ``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)) ) @defer.inlineCallbacks def send_request(destination): ret = yield self.transport_layer.make_membership_event( destination, room_id, user_id, membership, params, ) 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"] = [] # Strip off the fields that we want to clobber. pdu_dict.pop("origin", None) pdu_dict.pop("origin_server_ts", None) pdu_dict.pop("unsigned", None) builder = self.event_builder_factory.new(pdu_dict) add_hashes_and_signatures( builder, self.hs.hostname, self.hs.config.signing_key[0] ) ev = builder.build() defer.returnValue( (destination, ev) ) return self._try_destination_list( "make_" + membership, destinations, send_request, ) def send_join(self, destinations, pdu): """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 (str): Candidate homeservers which are probably participating in the room. pdu (BaseEvent): event to be sent Return: Deferred: resolves to a dict with members ``origin`` (a string giving the serer the event was sent to, ``state`` (?) and ``auth_chain``. Fails with a ``SynapseError`` if the chosen remote server returns a 300/400 code. Fails with a ``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, )) @defer.inlineCallbacks def send_request(destination): time_now = self._clock.time_msec() _, content = yield self.transport_layer.send_join( destination=destination, room_id=pdu.room_id, event_id=pdu.event_id, content=pdu.get_pdu_json(time_now), ) logger.debug("Got content: %s", content) state = [ event_from_pdu_json(p, outlier=True) for p in content.get("state", []) ] auth_chain = [ event_from_pdu_json(p, outlier=True) for p in content.get("auth_chain", []) ] pdus = { p.event_id: p for p in itertools.chain(state, auth_chain) } valid_pdus = yield self._check_sigs_and_hash_and_fetch( destination, list(pdus.values()), outlier=True, ) 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) defer.returnValue({ "state": signed_state, "auth_chain": signed_auth, "origin": destination, }) return self._try_destination_list("send_join", destinations, send_request) @defer.inlineCallbacks def send_invite(self, destination, room_id, event_id, pdu): time_now = self._clock.time_msec() try: code, content = yield self.transport_layer.send_invite( destination=destination, room_id=room_id, event_id=event_id, content=pdu.get_pdu_json(time_now), ) except HttpResponseException as e: if e.code == 403: raise e.to_synapse_error() raise pdu_dict = content["event"] logger.debug("Got response to send_invite: %s", pdu_dict) pdu = event_from_pdu_json(pdu_dict) # Check signatures are correct. pdu = yield self._check_sigs_and_hash(pdu) # FIXME: We should handle signature failures more gracefully. defer.returnValue(pdu) def send_leave(self, destinations, pdu): """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 (str): Candidate homeservers which are probably participating in the room. pdu (BaseEvent): event to be sent Return: Deferred: resolves to None. Fails with a ``SynapseError`` if the chosen remote server returns a 300/400 code. Fails with a ``RuntimeError`` if no servers were reachable. """ @defer.inlineCallbacks def send_request(destination): time_now = self._clock.time_msec() _, content = yield self.transport_layer.send_leave( destination=destination, room_id=pdu.room_id, event_id=pdu.event_id, content=pdu.get_pdu_json(time_now), ) logger.debug("Got content: %s", content) defer.returnValue(None) return self._try_destination_list("send_leave", destinations, send_request) 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, ) @defer.inlineCallbacks def query_auth(self, destination, room_id, event_id, local_auth): """ Params: destination (str) event_it (str) local_auth (list) """ time_now = self._clock.time_msec() send_content = { "auth_chain": [e.get_pdu_json(time_now) for e in local_auth], } code, content = yield self.transport_layer.send_query_auth( destination=destination, room_id=room_id, event_id=event_id, content=send_content, ) auth_chain = [ event_from_pdu_json(e) for e in content["auth_chain"] ] signed_auth = yield self._check_sigs_and_hash_and_fetch( destination, auth_chain, outlier=True ) signed_auth.sort(key=lambda e: e.depth) ret = { "auth_chain": signed_auth, "rejects": content.get("rejects", []), "missing": content.get("missing", []), } defer.returnValue(ret) @defer.inlineCallbacks def get_missing_events(self, destination, room_id, earliest_events_ids, latest_events, limit, min_depth, timeout): """Tries to fetch events we are missing. This is called when we receive an event without having received all of its ancestors. Args: destination (str) room_id (str) earliest_events_ids (list): 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): List of events we have received that we don't have all previous events for. limit (int): Maximum number of events to return. min_depth (int): Minimum depth of events tor return. timeout (int): Max time to wait in ms """ try: content = yield 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, ) events = [ event_from_pdu_json(e) for e in content.get("events", []) ] signed_events = yield self._check_sigs_and_hash_and_fetch( destination, events, outlier=False ) 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 = [] defer.returnValue(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, ) defer.returnValue(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.")