diff options
Diffstat (limited to 'synapse/http/endpoint.py')
| -rw-r--r-- | synapse/http/endpoint.py | 103 |
1 files changed, 8 insertions, 95 deletions
diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py index 87639b9151..00572c2897 100644 --- a/synapse/http/endpoint.py +++ b/synapse/http/endpoint.py @@ -12,8 +12,6 @@ # 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 socket - from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS from twisted.internet import defer, reactor from twisted.internet.error import ConnectError @@ -33,7 +31,7 @@ SERVER_CACHE = {} # our record of an individual server which can be tried to reach a destination. # -# "host" is actually a dotted-quad or ipv6 address string. Except when there's +# "host" is the hostname acquired from the SRV record. Except when there's # no SRV record, in which case it is the original hostname. _Server = collections.namedtuple( "_Server", "priority weight host port expires" @@ -297,20 +295,13 @@ def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE, clock=t payload = answer.payload - hosts = yield _get_hosts_for_srv_record( - dns_client, str(payload.target) - ) - - for (ip, ttl) in hosts: - host_ttl = min(answer.ttl, ttl) - - servers.append(_Server( - host=ip, - port=int(payload.port), - priority=int(payload.priority), - weight=int(payload.weight), - expires=int(clock.time()) + host_ttl, - )) + servers.append(_Server( + host=str(payload.target), + port=int(payload.port), + priority=int(payload.priority), + weight=int(payload.weight), + expires=int(clock.time()) + answer.ttl, + )) servers.sort() cache[service_name] = list(servers) @@ -328,81 +319,3 @@ def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE, clock=t raise e defer.returnValue(servers) - - -@defer.inlineCallbacks -def _get_hosts_for_srv_record(dns_client, host): - """Look up each of the hosts in a SRV record - - Args: - dns_client (twisted.names.dns.IResolver): - host (basestring): host to look up - - Returns: - Deferred[list[(str, int)]]: a list of (host, ttl) pairs - - """ - ip4_servers = [] - ip6_servers = [] - - def cb(res): - # lookupAddress and lookupIP6Address return a three-tuple - # giving the answer, authority, and additional sections of the - # response. - # - # we only care about the answers. - - return res[0] - - def eb(res, record_type): - if res.check(DNSNameError): - return [] - logger.warn("Error looking up %s for %s: %s", record_type, host, res) - return res - - # no logcontexts here, so we can safely fire these off and gatherResults - d1 = dns_client.lookupAddress(host).addCallbacks( - cb, eb, errbackArgs=("A", )) - d2 = dns_client.lookupIPV6Address(host).addCallbacks( - cb, eb, errbackArgs=("AAAA", )) - results = yield defer.DeferredList( - [d1, d2], consumeErrors=True) - - # if all of the lookups failed, raise an exception rather than blowing out - # the cache with an empty result. - if results and all(s == defer.FAILURE for (s, _) in results): - defer.returnValue(results[0][1]) - - for (success, result) in results: - if success == defer.FAILURE: - continue - - for answer in result: - if not answer.payload: - continue - - try: - if answer.type == dns.A: - ip = answer.payload.dottedQuad() - ip4_servers.append((ip, answer.ttl)) - elif answer.type == dns.AAAA: - ip = socket.inet_ntop( - socket.AF_INET6, answer.payload.address, - ) - ip6_servers.append((ip, answer.ttl)) - else: - # the most likely candidate here is a CNAME record. - # rfc2782 says srvs may not point to aliases. - logger.warn( - "Ignoring unexpected DNS record type %s for %s", - answer.type, host, - ) - continue - except Exception as e: - logger.warn("Ignoring invalid DNS response for %s: %s", - host, e) - continue - - # keep the ipv4 results before the ipv6 results, mostly to match historical - # behaviour. - defer.returnValue(ip4_servers + ip6_servers) |