MatrixSynapse/synapse/federation/federation_client.py

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# -*- 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)
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@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(
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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", []),
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}
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)