fix(activity): detect ipv4 mapped ipv6 connections

In the ActiveConnection check, properly handle the case where a service
listening on an IPv4 address is targeted by an IPv6 connection that
uses the special IPv6 range for mapping towards IPv4 addresses. This is
realized by transforming all IPv4 addresses into the IPv6 space.
Hopefully, this catches all corner-cases.

Fixes: #116

src/autosuspend/checks/activity.py

@@ -85,10 +85,23 @@ def __init__(self, name: str, ports: Iterable[int]) -> None:
         Activity.__init__(self, name)
         self._ports = ports
 
+    def normalize_address(
+        self, family: socket.AddressFamily, address: str
+    ) -> Tuple[socket.AddressFamily, str]:
+        if family == socket.AF_INET6:
+            # strip scope
+            return family, address.split("%")[0]
+        elif family == socket.AF_INET:
+            # convert to IPv6 to handle cases where an IPv4 address is targeted via IPv6
+            # to IPv4 mapping
+            return socket.AF_INET6, f"::ffff:{address}"
+        else:
+            return family, address
+
     def check(self) -> Optional[str]:
         # Find the addresses of the system
         own_addresses = [
-            (item.family, item.address.split("%")[0])
+            self.normalize_address(item.family, item.address)
             for sublist in psutil.net_if_addrs().values()
             for item in sublist
         ]
@@ -97,7 +110,8 @@ def check(self) -> Optional[str]:
             connection.laddr[1]
             for connection in psutil.net_connections()
             if (
-                (connection.family, connection.laddr[0]) in own_addresses
+                self.normalize_address(connection.family, connection.laddr[0])
+                in own_addresses
                 and connection.status == "ESTABLISHED"
                 and connection.laddr[1] in self._ports
             )

tests/test_checks_activity.py

@@ -345,6 +345,17 @@ def test_smoke(self) -> None:
                 "ESTABLISHED",
                 None,
             ),
+            # ipv6 with mapping to ipv4
+            # https://github.com/languitar/autosuspend/issues/116
+            psutil._common.sconn(
+                -1,
+                socket.AF_INET6,
+                socket.SOCK_STREAM,
+                (f"::ffff:{MY_ADDRESS}", MY_PORT),
+                ("42.42.42.42", 42),
+                "ESTABLISHED",
+                None,
+            ),
         ],
     )
     def test_connected(