diff options
Diffstat (limited to 'synapse/http/federation/matrix_federation_agent.py')
| -rw-r--r-- | synapse/http/federation/matrix_federation_agent.py | 247 |
1 files changed, 228 insertions, 19 deletions
diff --git a/synapse/http/federation/matrix_federation_agent.py b/synapse/http/federation/matrix_federation_agent.py index 0ec28c6696..f81fcd4301 100644 --- a/synapse/http/federation/matrix_federation_agent.py +++ b/synapse/http/federation/matrix_federation_agent.py @@ -12,16 +12,19 @@ # 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 json import logging +import attr +from netaddr import IPAddress from zope.interface import implementer from twisted.internet import defer from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS -from twisted.web.client import URI, Agent, HTTPConnectionPool +from twisted.web.client import URI, Agent, HTTPConnectionPool, readBody +from twisted.web.http_headers import Headers from twisted.web.iweb import IAgent -from synapse.http.endpoint import parse_server_name from synapse.http.federation.srv_resolver import SrvResolver, pick_server_from_list from synapse.util.logcontext import make_deferred_yieldable @@ -41,13 +44,19 @@ class MatrixFederationAgent(object): tls_client_options_factory (ClientTLSOptionsFactory|None): factory to use for fetching client tls options, or none to disable TLS. + _well_known_tls_policy (IPolicyForHTTPS|None): + TLS policy to use for fetching .well-known files. None to use a default + (browser-like) implementation. + srv_resolver (SrvResolver|None): SRVResolver impl to use for looking up SRV records. None to use a default implementation. """ def __init__( - self, reactor, tls_client_options_factory, _srv_resolver=None, + self, reactor, tls_client_options_factory, + _well_known_tls_policy=None, + _srv_resolver=None, ): self._reactor = reactor self._tls_client_options_factory = tls_client_options_factory @@ -60,6 +69,14 @@ class MatrixFederationAgent(object): self._pool.maxPersistentPerHost = 5 self._pool.cachedConnectionTimeout = 2 * 60 + agent_args = {} + if _well_known_tls_policy is not None: + # the param is called 'contextFactory', but actually passing a + # contextfactory is deprecated, and it expects an IPolicyForHTTPS. + agent_args['contextFactory'] = _well_known_tls_policy + _well_known_agent = Agent(self._reactor, pool=self._pool, **agent_args) + self._well_known_agent = _well_known_agent + @defer.inlineCallbacks def request(self, method, uri, headers=None, bodyProducer=None): """ @@ -85,35 +102,39 @@ class MatrixFederationAgent(object): response from being received (including problems that prevent the request from being sent). """ + parsed_uri = URI.fromBytes(uri, defaultPort=-1) + res = yield self._route_matrix_uri(parsed_uri) - parsed_uri = URI.fromBytes(uri) - server_name_bytes = parsed_uri.netloc - host, port = parse_server_name(server_name_bytes.decode("ascii")) - + # set up the TLS connection params + # # XXX disabling TLS is really only supported here for the benefit of the # unit tests. We should make the UTs cope with TLS rather than having to make # the code support the unit tests. if self._tls_client_options_factory is None: tls_options = None else: - tls_options = self._tls_client_options_factory.get_options(host) + tls_options = self._tls_client_options_factory.get_options( + res.tls_server_name.decode("ascii") + ) - if port is not None: - target = (host, port) + # make sure that the Host header is set correctly + if headers is None: + headers = Headers() else: - service_name = b"_matrix._tcp.%s" % (server_name_bytes, ) - server_list = yield self._srv_resolver.resolve_service(service_name) - if not server_list: - target = (host, 8448) - logger.debug("No SRV record for %s, using %s", host, target) - else: - target = pick_server_from_list(server_list) + headers = headers.copy() + + if not headers.hasHeader(b'host'): + headers.addRawHeader(b'host', res.host_header) class EndpointFactory(object): @staticmethod def endpointForURI(_uri): - logger.info("Connecting to %s:%s", target[0], target[1]) - ep = HostnameEndpoint(self._reactor, host=target[0], port=target[1]) + logger.info( + "Connecting to %s:%i", + res.target_host.decode("ascii"), + res.target_port, + ) + ep = HostnameEndpoint(self._reactor, res.target_host, res.target_port) if tls_options is not None: ep = wrapClientTLS(tls_options, ep) return ep @@ -123,3 +144,191 @@ class MatrixFederationAgent(object): agent.request(method, uri, headers, bodyProducer) ) defer.returnValue(res) + + @defer.inlineCallbacks + def _route_matrix_uri(self, parsed_uri, lookup_well_known=True): + """Helper for `request`: determine the routing for a Matrix URI + + Args: + parsed_uri (twisted.web.client.URI): uri to route. Note that it should be + parsed with URI.fromBytes(uri, defaultPort=-1) to set the `port` to -1 + if there is no explicit port given. + + lookup_well_known (bool): True if we should look up the .well-known file if + there is no SRV record. + + Returns: + Deferred[_RoutingResult] + """ + # check for an IP literal + try: + ip_address = IPAddress(parsed_uri.host.decode("ascii")) + except Exception: + # not an IP address + ip_address = None + + if ip_address: + port = parsed_uri.port + if port == -1: + port = 8448 + defer.returnValue(_RoutingResult( + host_header=parsed_uri.netloc, + tls_server_name=parsed_uri.host, + target_host=parsed_uri.host, + target_port=port, + )) + + if parsed_uri.port != -1: + # there is an explicit port + defer.returnValue(_RoutingResult( + host_header=parsed_uri.netloc, + tls_server_name=parsed_uri.host, + target_host=parsed_uri.host, + target_port=parsed_uri.port, + )) + + # try a SRV lookup + service_name = b"_matrix._tcp.%s" % (parsed_uri.host,) + server_list = yield self._srv_resolver.resolve_service(service_name) + + if not server_list and lookup_well_known: + # try a .well-known lookup + well_known_server = yield self._get_well_known(parsed_uri.host) + + if well_known_server: + # if we found a .well-known, start again, but don't do another + # .well-known lookup. + + # parse the server name in the .well-known response into host/port. + # (This code is lifted from twisted.web.client.URI.fromBytes). + if b':' in well_known_server: + well_known_host, well_known_port = well_known_server.rsplit(b':', 1) + try: + well_known_port = int(well_known_port) + except ValueError: + # the part after the colon could not be parsed as an int + # - we assume it is an IPv6 literal with no port (the closing + # ']' stops it being parsed as an int) + well_known_host, well_known_port = well_known_server, -1 + else: + well_known_host, well_known_port = well_known_server, -1 + + new_uri = URI( + scheme=parsed_uri.scheme, + netloc=well_known_server, + host=well_known_host, + port=well_known_port, + path=parsed_uri.path, + params=parsed_uri.params, + query=parsed_uri.query, + fragment=parsed_uri.fragment, + ) + + res = yield self._route_matrix_uri(new_uri, lookup_well_known=False) + defer.returnValue(res) + + if not server_list: + target_host = parsed_uri.host + port = 8448 + logger.debug( + "No SRV record for %s, using %s:%i", + parsed_uri.host.decode("ascii"), target_host.decode("ascii"), port, + ) + else: + target_host, port = pick_server_from_list(server_list) + logger.debug( + "Picked %s:%i from SRV records for %s", + target_host.decode("ascii"), port, parsed_uri.host.decode("ascii"), + ) + + defer.returnValue(_RoutingResult( + host_header=parsed_uri.netloc, + tls_server_name=parsed_uri.host, + target_host=target_host, + target_port=port, + )) + + @defer.inlineCallbacks + def _get_well_known(self, server_name): + """Attempt to fetch and parse a .well-known file for the given server + + Args: + server_name (bytes): name of the server, from the requested url + + Returns: + Deferred[bytes|None]: either the new server name, from the .well-known, or + None if there was no .well-known file. + """ + # FIXME: add a cache + + uri = b"https://%s/.well-known/matrix/server" % (server_name, ) + uri_str = uri.decode("ascii") + logger.info("Fetching %s", uri_str) + try: + response = yield make_deferred_yieldable( + self._well_known_agent.request(b"GET", uri), + ) + except Exception as e: + logger.info("Connection error fetching %s: %s", uri_str, e) + defer.returnValue(None) + + body = yield make_deferred_yieldable(readBody(response)) + + if response.code != 200: + logger.info("Error response %i from %s", response.code, uri_str) + defer.returnValue(None) + + try: + parsed_body = json.loads(body.decode('utf-8')) + logger.info("Response from .well-known: %s", parsed_body) + if not isinstance(parsed_body, dict): + raise Exception("not a dict") + if "m.server" not in parsed_body: + raise Exception("Missing key 'm.server'") + except Exception as e: + raise Exception("invalid .well-known response from %s: %s" % (uri_str, e,)) + defer.returnValue(parsed_body["m.server"].encode("ascii")) + + +@attr.s +class _RoutingResult(object): + """The result returned by `_route_matrix_uri`. + + Contains the parameters needed to direct a federation connection to a particular + server. + + Where a SRV record points to several servers, this object contains a single server + chosen from the list. + """ + + host_header = attr.ib() + """ + The value we should assign to the Host header (host:port from the matrix + URI, or .well-known). + + :type: bytes + """ + + tls_server_name = attr.ib() + """ + The server name we should set in the SNI (typically host, without port, from the + matrix URI or .well-known) + + :type: bytes + """ + + target_host = attr.ib() + """ + The hostname (or IP literal) we should route the TCP connection to (the target of the + SRV record, or the hostname from the URL/.well-known) + + :type: bytes + """ + + target_port = attr.ib() + """ + The port we should route the TCP connection to (the target of the SRV record, or + the port from the URL/.well-known, or 8448) + + :type: int + """ |