Implementation of server_acls

... as described at
https://docs.google.com/document/d/1EttUVzjc2DWe2ciw4XPtNpUpIl9lWXGEsy2ewDS7rtw.

tests/federation/test_federation_server.py

@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector 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.
+import logging
+
+from synapse.events import FrozenEvent
+from synapse.federation.federation_server import server_matches_acl_event
+from tests import unittest
+
+
+@unittest.DEBUG
+class ServerACLsTestCase(unittest.TestCase):
+    def test_blacklisted_server(self):
+        e = _create_acl_event({
+            "allow": ["*"],
+            "deny": ["evil.com"],
+        })
+        logging.info("ACL event: %s", e.content)
+
+        self.assertFalse(server_matches_acl_event("evil.com", e))
+        self.assertFalse(server_matches_acl_event("EVIL.COM", e))
+
+        self.assertTrue(server_matches_acl_event("evil.com.au", e))
+        self.assertTrue(server_matches_acl_event("honestly.not.evil.com", e))
+
+    def test_block_ip_literals(self):
+        e = _create_acl_event({
+            "allow_ip_literals": False,
+            "allow": ["*"],
+        })
+        logging.info("ACL event: %s", e.content)
+
+        self.assertFalse(server_matches_acl_event("1.2.3.4", e))
+        self.assertTrue(server_matches_acl_event("1a.2.3.4", e))
+        self.assertFalse(server_matches_acl_event("[1:2::]", e))
+        self.assertTrue(server_matches_acl_event("1:2:3:4", e))
+
+
+def _create_acl_event(content):
+    return FrozenEvent({
+        "room_id": "!a:b",
+        "event_id": "$a:b",
+        "type": "m.room.server_acls",
+        "sender": "@a:b",
+        "content": content
+    })