🔗 Fix connecting to link-local IPv6 addresses (#4556)

aio-libs · Oct 16, 2020 · 86107ed · 86107ed
1 parent 2940484
commit 86107ed
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Showing 3 changed files with 28 additions and 12 deletions.
diff --git a/CHANGES/4554.bugfix b/CHANGES/4554.bugfix
@@ -0,0 +1 @@
+Fix connecting to link-local IPv6 addresses.
diff --git a/aiohttp/resolver.py b/aiohttp/resolver.py
@@ -31,11 +31,23 @@ async def resolve(self, host: str, port: int=0,
 
         hosts = []
         for family, _, proto, _, address in infos:
-            hosts.append(
-                {'hostname': host,
-                 'host': address[0], 'port': address[1],
-                 'family': family, 'proto': proto,
-                 'flags': socket.AI_NUMERICHOST})
+            if family == socket.AF_INET6 and address[3]:  # type: ignore
+                # This is essential for link-local IPv6 addresses.
+                # LL IPv6 is a VERY rare case. Strictly speaking, we should use
+                # getnameinfo() unconditionally, but performance makes sense.
+                host, _port = socket.getnameinfo(
+                    address, socket.NI_NUMERICHOST | socket.NI_NUMERICSERV)
+                port = int(_port)
+            else:
+                host, port = address[:2]
+            hosts.append({
+                'hostname': host,
+                'host': host,
+                'port': port,
+                'family': family,
+                'proto': proto,
+                'flags': socket.AI_NUMERICHOST | socket.AI_NUMERICSERV,
+            })
 
         return hosts
 
@@ -62,11 +74,14 @@ async def resolve(self, host: str, port: int=0,
             raise OSError(msg) from exc
         hosts = []
         for address in resp.addresses:
-            hosts.append(
-                {'hostname': host,
-                 'host': address, 'port': port,
-                 'family': family, 'proto': 0,
-                 'flags': socket.AI_NUMERICHOST})
+            hosts.append({
+                'hostname': host,
+                'host': address,
+                'port': port,
+                'family': family,
+                'proto': 0,
+                'flags': socket.AI_NUMERICHOST | socket.AI_NUMERICSERV,
+            })
 
         if not hosts:
             raise OSError("DNS lookup failed")

diff --git a/tests/test_connector.py b/tests/test_connector.py
@@ -652,10 +652,10 @@ async def test_tcp_connector_resolve_host(loop) -> None:
     for rec in res:
         if rec['family'] == socket.AF_INET:
             assert rec['host'] == '127.0.0.1'
-            assert rec['hostname'] == 'localhost'
+            assert rec['hostname'] == '127.0.0.1'
             assert rec['port'] == 8080
         elif rec['family'] == socket.AF_INET6:
-            assert rec['hostname'] == 'localhost'
+            assert rec['hostname'] == '::1'
             assert rec['port'] == 8080
             if platform.system() == 'Darwin':
                 assert rec['host'] in ('::1', 'fe80::1', 'fe80::1%lo0')