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Diffstat (limited to 'synapse/federation/federation_client.py')
| -rw-r--r-- | synapse/federation/federation_client.py | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py new file mode 100644 index 0000000000..e1539bd0e0 --- /dev/null +++ b/synapse/federation/federation_client.py @@ -0,0 +1,409 @@ +# -*- coding: utf-8 -*- +# Copyright 2015 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. + + +from twisted.internet import defer + +from .units import Edu + +from synapse.util.logutils import log_function +from synapse.events import FrozenEvent +from synapse.events.utils import prune_event + +from syutil.jsonutil import encode_canonical_json + +from synapse.crypto.event_signing import check_event_content_hash + +from synapse.api.errors import SynapseError + +import logging + + +logger = logging.getLogger(__name__) + + +class FederationClient(object): + @log_function + def send_pdu(self, pdu, destinations): + """Informs the replication layer about a new PDU generated within the + home server that should be transmitted to others. + + TODO: Figure out when we should actually resolve the deferred. + + Args: + pdu (Pdu): The new Pdu. + + Returns: + Deferred: Completes when we have successfully processed the PDU + and replicated it to any interested remote home servers. + """ + order = self._order + self._order += 1 + + logger.debug("[%s] transaction_layer.enqueue_pdu... ", pdu.event_id) + + # TODO, add errback, etc. + self._transaction_queue.enqueue_pdu(pdu, destinations, order) + + logger.debug( + "[%s] transaction_layer.enqueue_pdu... done", + pdu.event_id + ) + + @log_function + def send_edu(self, destination, edu_type, content): + edu = Edu( + origin=self.server_name, + destination=destination, + edu_type=edu_type, + content=content, + ) + + # TODO, add errback, etc. + self._transaction_queue.enqueue_edu(edu) + return defer.succeed(None) + + @log_function + def send_failure(self, failure, destination): + self._transaction_queue.enqueue_failure(failure, destination) + return defer.succeed(None) + + @log_function + def make_query(self, destination, query_type, args, + retry_on_dns_fail=True): + """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. + + Returns: + a Deferred which will eventually yield a JSON object from the + response + """ + return self.transport_layer.make_query( + destination, query_type, args, retry_on_dns_fail=retry_on_dns_fail + ) + + @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 = [ + self.event_from_pdu_json(p, outlier=False) + for p in transaction_data["pdus"] + ] + + for i, pdu in enumerate(pdus): + pdus[i] = yield self._check_sigs_and_hash(pdu) + + # FIXME: We should handle signature failures more gracefully. + + defer.returnValue(pdus) + + @defer.inlineCallbacks + @log_function + def get_pdu(self, destinations, event_id, outlier=False): + """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. + + This will persist the PDU locally upon receipt. + + Args: + destinations (list): Which home servers to query + pdu_origin (str): The home server that originally sent the pdu. + event_id (str) + 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` + + Returns: + Deferred: Results in the requested PDU. + """ + + # TODO: Rate limit the number of times we try and get the same event. + + pdu = None + for destination in destinations: + try: + transaction_data = yield self.transport_layer.get_event( + destination, event_id + ) + + logger.debug("transaction_data %r", transaction_data) + + pdu_list = [ + self.event_from_pdu_json(p, outlier=outlier) + for p in transaction_data["pdus"] + ] + + if pdu_list: + pdu = pdu_list[0] + + # Check signatures are correct. + pdu = yield self._check_sigs_and_hash(pdu) + + break + + except Exception as e: + logger.info( + "Failed to get PDU %s from %s because %s", + event_id, destination, e, + ) + continue + + defer.returnValue(pdu) + + @defer.inlineCallbacks + @log_function + def get_state_for_room(self, destination, room_id, event_id): + """Requests all of the `current` state PDUs for a given room 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: Results in a list of PDUs. + """ + + result = yield self.transport_layer.get_room_state( + destination, room_id, event_id=event_id, + ) + + pdus = [ + self.event_from_pdu_json(p, outlier=True) for p in result["pdus"] + ] + + auth_chain = [ + self.event_from_pdu_json(p, outlier=True) + for p in result.get("auth_chain", []) + ] + + for i, pdu in enumerate(pdus): + pdus[i] = yield self._check_sigs_and_hash(pdu) + + # FIXME: We should handle signature failures more gracefully. + + for i, pdu in enumerate(auth_chain): + auth_chain[i] = yield self._check_sigs_and_hash(pdu) + + # FIXME: We should handle signature failures more gracefully. + + defer.returnValue((pdus, auth_chain)) + + @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 = [ + self.event_from_pdu_json(p, outlier=True) + for p in res["auth_chain"] + ] + + for i, pdu in enumerate(auth_chain): + auth_chain[i] = yield self._check_sigs_and_hash(pdu) + + # FIXME: We should handle signature failures more gracefully. + + auth_chain.sort(key=lambda e: e.depth) + + defer.returnValue(auth_chain) + + @defer.inlineCallbacks + def make_join(self, destination, room_id, user_id): + ret = yield self.transport_layer.make_join( + destination, room_id, user_id + ) + + pdu_dict = ret["event"] + + logger.debug("Got response to make_join: %s", pdu_dict) + + defer.returnValue(self.event_from_pdu_json(pdu_dict)) + + @defer.inlineCallbacks + def send_join(self, destination, pdu): + 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 = [ + self.event_from_pdu_json(p, outlier=True) + for p in content.get("state", []) + ] + + auth_chain = [ + self.event_from_pdu_json(p, outlier=True) + for p in content.get("auth_chain", []) + ] + + for i, pdu in enumerate(state): + state[i] = yield self._check_sigs_and_hash(pdu) + + # FIXME: We should handle signature failures more gracefully. + + for i, pdu in enumerate(auth_chain): + auth_chain[i] = yield self._check_sigs_and_hash(pdu) + + # FIXME: We should handle signature failures more gracefully. + + auth_chain.sort(key=lambda e: e.depth) + + defer.returnValue({ + "state": state, + "auth_chain": auth_chain, + }) + + @defer.inlineCallbacks + def send_invite(self, destination, room_id, event_id, pdu): + time_now = self._clock.time_msec() + 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), + ) + + pdu_dict = content["event"] + + logger.debug("Got response to send_invite: %s", pdu_dict) + + pdu = self.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) + + @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 = [ + (yield self._check_sigs_and_hash(self.event_from_pdu_json(e))) + for e in content["auth_chain"] + ] + + ret = { + "auth_chain": auth_chain, + "rejects": content.get("rejects", []), + "missing": content.get("missing", []), + } + + defer.returnValue(ret) + + def event_from_pdu_json(self, pdu_json, outlier=False): + event = FrozenEvent( + pdu_json + ) + + event.internal_metadata.outlier = outlier + + return event + + @defer.inlineCallbacks + def _check_sigs_and_hash(self, pdu): + """Throws a SynapseError if the PDU does not have the correct + signatures. + + Returns: + FrozenEvent: Either the given event or it redacted if it failed the + content hash check. + """ + # Check signatures are correct. + redacted_event = prune_event(pdu) + redacted_pdu_json = redacted_event.get_pdu_json() + + try: + yield self.keyring.verify_json_for_server( + pdu.origin, redacted_pdu_json + ) + except SynapseError: + logger.warn( + "Signature check failed for %s redacted to %s", + encode_canonical_json(pdu.get_pdu_json()), + encode_canonical_json(redacted_pdu_json), + ) + raise + + if not check_event_content_hash(pdu): + logger.warn( + "Event content has been tampered, redacting %s, %s", + pdu.event_id, encode_canonical_json(pdu.get_dict()) + ) + defer.returnValue(redacted_event) + + defer.returnValue(pdu) |