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Diffstat (limited to 'synapse/federation/federation_server.py')
| -rw-r--r-- | synapse/federation/federation_server.py | 462 |
1 files changed, 462 insertions, 0 deletions
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py new file mode 100644 index 0000000000..5fbd8b19de --- /dev/null +++ b/synapse/federation/federation_server.py @@ -0,0 +1,462 @@ +# -*- 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 Transaction, Edu + +from synapse.util.logutils import log_function +from synapse.util.logcontext import PreserveLoggingContext +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 FederationError, SynapseError + +import logging + + +logger = logging.getLogger(__name__) + + +class FederationServer(object): + def set_handler(self, handler): + """Sets the handler that the replication layer will use to communicate + receipt of new PDUs from other home servers. The required methods are + documented on :py:class:`.ReplicationHandler`. + """ + self.handler = handler + + def register_edu_handler(self, edu_type, handler): + if edu_type in self.edu_handlers: + raise KeyError("Already have an EDU handler for %s" % (edu_type,)) + + self.edu_handlers[edu_type] = handler + + def register_query_handler(self, query_type, handler): + """Sets the handler callable that will be used to handle an incoming + federation Query of the given type. + + Args: + query_type (str): Category name of the query, which should match + the string used by make_query. + handler (callable): Invoked to handle incoming queries of this type + + handler is invoked as: + result = handler(args) + + where 'args' is a dict mapping strings to strings of the query + arguments. It should return a Deferred that will eventually yield an + object to encode as JSON. + """ + if query_type in self.query_handlers: + raise KeyError( + "Already have a Query handler for %s" % (query_type,) + ) + + self.query_handlers[query_type] = handler + + @defer.inlineCallbacks + @log_function + def on_backfill_request(self, origin, room_id, versions, limit): + pdus = yield self.handler.on_backfill_request( + origin, room_id, versions, limit + ) + + defer.returnValue((200, self._transaction_from_pdus(pdus).get_dict())) + + @defer.inlineCallbacks + @log_function + def on_incoming_transaction(self, transaction_data): + transaction = Transaction(**transaction_data) + + for p in transaction.pdus: + if "unsigned" in p: + unsigned = p["unsigned"] + if "age" in unsigned: + p["age"] = unsigned["age"] + if "age" in p: + p["age_ts"] = int(self._clock.time_msec()) - int(p["age"]) + del p["age"] + + pdu_list = [ + self.event_from_pdu_json(p) for p in transaction.pdus + ] + + logger.debug("[%s] Got transaction", transaction.transaction_id) + + response = yield self.transaction_actions.have_responded(transaction) + + if response: + logger.debug( + "[%s] We've already responed to this request", + transaction.transaction_id + ) + defer.returnValue(response) + return + + logger.debug("[%s] Transaction is new", transaction.transaction_id) + + with PreserveLoggingContext(): + dl = [] + for pdu in pdu_list: + dl.append(self._handle_new_pdu(transaction.origin, pdu)) + + if hasattr(transaction, "edus"): + for edu in [Edu(**x) for x in transaction.edus]: + self.received_edu( + transaction.origin, + edu.edu_type, + edu.content + ) + + results = yield defer.DeferredList(dl) + + ret = [] + for r in results: + if r[0]: + ret.append({}) + else: + logger.exception(r[1]) + ret.append({"error": str(r[1])}) + + logger.debug("Returning: %s", str(ret)) + + yield self.transaction_actions.set_response( + transaction, + 200, response + ) + defer.returnValue((200, response)) + + def received_edu(self, origin, edu_type, content): + if edu_type in self.edu_handlers: + self.edu_handlers[edu_type](origin, content) + else: + logger.warn("Received EDU of type %s with no handler", edu_type) + + @defer.inlineCallbacks + @log_function + def on_context_state_request(self, origin, room_id, event_id): + if event_id: + pdus = yield self.handler.get_state_for_pdu( + origin, room_id, event_id, + ) + auth_chain = yield self.store.get_auth_chain( + [pdu.event_id for pdu in pdus] + ) + else: + raise NotImplementedError("Specify an event") + + defer.returnValue((200, { + "pdus": [pdu.get_pdu_json() for pdu in pdus], + "auth_chain": [pdu.get_pdu_json() for pdu in auth_chain], + })) + + @defer.inlineCallbacks + @log_function + def on_pdu_request(self, origin, event_id): + pdu = yield self._get_persisted_pdu(origin, event_id) + + if pdu: + defer.returnValue( + (200, self._transaction_from_pdus([pdu]).get_dict()) + ) + else: + defer.returnValue((404, "")) + + @defer.inlineCallbacks + @log_function + def on_pull_request(self, origin, versions): + raise NotImplementedError("Pull transactions not implemented") + + @defer.inlineCallbacks + def on_query_request(self, query_type, args): + if query_type in self.query_handlers: + response = yield self.query_handlers[query_type](args) + defer.returnValue((200, response)) + else: + defer.returnValue( + (404, "No handler for Query type '%s'" % (query_type,)) + ) + + @defer.inlineCallbacks + def on_make_join_request(self, room_id, user_id): + pdu = yield self.handler.on_make_join_request(room_id, user_id) + time_now = self._clock.time_msec() + defer.returnValue({"event": pdu.get_pdu_json(time_now)}) + + @defer.inlineCallbacks + def on_invite_request(self, origin, content): + pdu = self.event_from_pdu_json(content) + ret_pdu = yield self.handler.on_invite_request(origin, pdu) + time_now = self._clock.time_msec() + defer.returnValue((200, {"event": ret_pdu.get_pdu_json(time_now)})) + + @defer.inlineCallbacks + def on_send_join_request(self, origin, content): + logger.debug("on_send_join_request: content: %s", content) + pdu = self.event_from_pdu_json(content) + logger.debug("on_send_join_request: pdu sigs: %s", pdu.signatures) + res_pdus = yield self.handler.on_send_join_request(origin, pdu) + time_now = self._clock.time_msec() + defer.returnValue((200, { + "state": [p.get_pdu_json(time_now) for p in res_pdus["state"]], + "auth_chain": [ + p.get_pdu_json(time_now) for p in res_pdus["auth_chain"] + ], + })) + + @defer.inlineCallbacks + def on_event_auth(self, origin, room_id, event_id): + time_now = self._clock.time_msec() + auth_pdus = yield self.handler.on_event_auth(event_id) + defer.returnValue((200, { + "auth_chain": [a.get_pdu_json(time_now) for a in auth_pdus], + })) + + @defer.inlineCallbacks + def on_query_auth_request(self, origin, content, event_id): + """ + Content is a dict with keys:: + auth_chain (list): A list of events that give the auth chain. + missing (list): A list of event_ids indicating what the other + side (`origin`) think we're missing. + rejects (dict): A mapping from event_id to a 2-tuple of reason + string and a proof (or None) of why the event was rejected. + The keys of this dict give the list of events the `origin` has + rejected. + + Args: + origin (str) + content (dict) + event_id (str) + + Returns: + Deferred: Results in `dict` with the same format as `content` + """ + auth_chain = [ + (yield self._check_sigs_and_hash(self.event_from_pdu_json(e))) + for e in content["auth_chain"] + ] + + missing = [ + (yield self._check_sigs_and_hash(self.event_from_pdu_json(e))) + for e in content.get("missing", []) + ] + + ret = yield self.handler.on_query_auth( + origin, event_id, auth_chain, content.get("rejects", []), missing + ) + + time_now = self._clock.time_msec() + send_content = { + "auth_chain": [ + e.get_pdu_json(time_now) + for e in ret["auth_chain"] + ], + "rejects": ret.get("rejects", []), + "missing": ret.get("missing", []), + } + + defer.returnValue( + (200, send_content) + ) + + @log_function + def _get_persisted_pdu(self, origin, event_id, do_auth=True): + """ Get a PDU from the database with given origin and id. + + Returns: + Deferred: Results in a `Pdu`. + """ + return self.handler.get_persisted_pdu( + origin, event_id, do_auth=do_auth + ) + + def _transaction_from_pdus(self, pdu_list): + """Returns a new Transaction containing the given PDUs suitable for + transmission. + """ + time_now = self._clock.time_msec() + pdus = [p.get_pdu_json(time_now) for p in pdu_list] + return Transaction( + origin=self.server_name, + pdus=pdus, + origin_server_ts=int(time_now), + destination=None, + ) + + @defer.inlineCallbacks + @log_function + def _handle_new_pdu(self, origin, pdu, max_recursion=10): + # We reprocess pdus when we have seen them only as outliers + existing = yield self._get_persisted_pdu( + origin, pdu.event_id, do_auth=False + ) + + # FIXME: Currently we fetch an event again when we already have it + # if it has been marked as an outlier. + + already_seen = ( + existing and ( + not existing.internal_metadata.is_outlier() + or pdu.internal_metadata.is_outlier() + ) + ) + if already_seen: + logger.debug("Already seen pdu %s", pdu.event_id) + defer.returnValue({}) + return + + # Check signature. + try: + pdu = yield self._check_sigs_and_hash(pdu) + except SynapseError as e: + raise FederationError( + "ERROR", + e.code, + e.msg, + affected=pdu.event_id, + ) + + state = None + + auth_chain = [] + + have_seen = yield self.store.have_events( + [ev for ev, _ in pdu.prev_events] + ) + + fetch_state = False + + # Get missing pdus if necessary. + if not pdu.internal_metadata.is_outlier(): + # We only backfill backwards to the min depth. + min_depth = yield self.handler.get_min_depth_for_context( + pdu.room_id + ) + + logger.debug( + "_handle_new_pdu min_depth for %s: %d", + pdu.room_id, min_depth + ) + + if min_depth and pdu.depth > min_depth and max_recursion > 0: + for event_id, hashes in pdu.prev_events: + if event_id not in have_seen: + logger.debug( + "_handle_new_pdu requesting pdu %s", + event_id + ) + + try: + new_pdu = yield self.federation_client.get_pdu( + [origin, pdu.origin], + event_id=event_id, + ) + + if new_pdu: + yield self._handle_new_pdu( + origin, + new_pdu, + max_recursion=max_recursion-1 + ) + + logger.debug("Processed pdu %s", event_id) + else: + logger.warn("Failed to get PDU %s", event_id) + fetch_state = True + except: + # TODO(erikj): Do some more intelligent retries. + logger.exception("Failed to get PDU") + fetch_state = True + else: + prevs = {e_id for e_id, _ in pdu.prev_events} + seen = set(have_seen.keys()) + if prevs - seen: + fetch_state = True + else: + fetch_state = True + + if fetch_state: + # We need to get the state at this event, since we haven't + # processed all the prev events. + logger.debug( + "_handle_new_pdu getting state for %s", + pdu.room_id + ) + state, auth_chain = yield self.get_state_for_room( + origin, pdu.room_id, pdu.event_id, + ) + + ret = yield self.handler.on_receive_pdu( + origin, + pdu, + backfilled=False, + state=state, + auth_chain=auth_chain, + ) + + defer.returnValue(ret) + + def __str__(self): + return "<ReplicationLayer(%s)>" % self.server_name + + 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) |