[fix] WireGuard auto tunnel provisioning broken with IPv6 #721

CHANGES.rst

@@ -4,7 +4,11 @@ Changelog
 Version 1.3.0 [unreleased]
 --------------------------
 
-Work in progress.
+Bugfixes
+~~~~~~~~
+
+- Fixed WireGuard auto tunnel provisioning broken with IPv6 subnets `#721
+  <https://github.com/openwisp/openwisp-controller/issues/721>`_
 
 Version 1.2.2 [2026-03-06]
 --------------------------

openwisp_controller/config/base/vpn.py

@@ -629,6 +629,12 @@ def auto_client(self, auto_cert=True, template_backend_class=None):
                     vxlan=self.config.get("vxlan", [{}])[0],
                     **context_keys,
                 )
+                if self.subnet and self.subnet.subnet.version == 6:
+                    for interface in auto.get("interfaces", []):
+                        if interface.get("type") == "wireguard":
+                            for addr in interface.get("addresses", []):
+                                addr["family"] = "ipv6"
+                                addr["mask"] = 128
             # If the backend is 'zerotier' then
             # call auto_client and update the config
             elif self._is_backend_type("zerotier") and template_backend_class:

openwisp_controller/config/tests/test_vpn.py

@@ -640,6 +640,26 @@ def test_auto_client(self):
         )
         self.assertEqual(auto, expected)
 
+    def test_auto_client_ipv6(self):
+        org = self._get_org()
+        device, vpn, template = self._create_wireguard_vpn_template(
+            vpn_options={
+                "organization": org,
+                "subnet": self._create_subnet(
+                    name="wireguard ipv6", subnet="fdca:1234::/64", organization=org
+                ),
+            }
+        )
+        auto = vpn.auto_client(template_backend_class=template.backend_class)
+        wg_interface = next(
+            (i for i in auto["interfaces"] if i.get("type") == "wireguard"), None
+        )
+        self.assertIsNotNone(wg_interface, "WireGuard interface not found")
+        addresses = wg_interface["addresses"]
+        self.assertEqual(len(addresses), 1)
+        self.assertEqual(addresses[0]["family"], "ipv6")
+        self.assertEqual(addresses[0]["mask"], 128)
+
     def test_change_vpn_backend(self):
         vpn = self._create_vpn(name="new", backend=self._BACKENDS["openvpn"])
         subnet = self._create_subnet(
@@ -996,6 +1016,28 @@ def test_auto_client(self):
         )
         self.assertEqual(auto, expected)
 
+    def test_auto_client_ipv6(self):
+        org = self._get_org()
+        device, vpn, template = self._create_vxlan_vpn_template(
+            vpn_options={
+                "organization": org,
+                "subnet": self._create_subnet(
+                    name="vxlan wireguard ipv6",
+                    subnet="fdca:1234::/64",
+                    organization=org,
+                ),
+            }
+        )
+        auto = vpn.auto_client(template_backend_class=template.backend_class)
+        wg_interface = next(
+            (i for i in auto["interfaces"] if i.get("type") == "wireguard"), None
+        )
+        self.assertIsNotNone(wg_interface, "WireGuard interface not found")
+        addresses = wg_interface["addresses"]
+        self.assertEqual(len(addresses), 1)
+        self.assertEqual(addresses[0]["family"], "ipv6")
+        self.assertEqual(addresses[0]["mask"], 128)
+
 
 class TestVxlanTransaction(
     BaseTestVpn, TestVxlanWireguardVpnMixin, TransactionTestCase

openwisp_controller/config/tests/utils.py

@@ -187,8 +187,8 @@ class TestVxlanWireguardVpnMixin(CreateIpamModelsMixin):
     def _create_vxlan_tunnel(self, config=None, **kwargs):
         if config is None:
             config = {"wireguard": [{"name": "wg0", "port": 51820}]}
-        org = self._get_org()
-        subnet = self._create_subnet(
+        org = kwargs.pop("organization", None) or self._get_org()
+        subnet = kwargs.pop("subnet", None) or self._create_subnet(
             name="wireguard test", subnet="10.0.0.0/16", organization=org
         )
         tunnel = self._create_vpn(