fix(nova-understack): fix client/target prefix handling

The calculation of the target prefix from the client IP was incorrect
based on the actual prefixes in use. This updates the code to have the
correct client side prefixes and then updates the tests to match while
including the correct target side prefixes as well.

Author: cardoe

python/nova-understack/ironic_understack/nautobot_client.py

@@ -30,12 +30,19 @@ def address(self) -> str:
     @property
     def target_network(self) -> ipaddress.IPv4Network:
         """Returns the respective target-side network."""
-        third_octet = self.address.split(".")[2]
-        if third_octet not in ["0", "128"]:
+        target_a_prefix = ipaddress.IPv4Network("100.127.0.0/17")
+        target_b_prefix = ipaddress.IPv4Network("100.127.128.0/17")
+        client_a_prefix = ipaddress.IPv4Network("100.126.0.0/17")
+        client_b_prefix = ipaddress.IPv4Network("100.126.128.0/17")
+
+        if self.interface.ip in client_a_prefix:
+            return target_a_prefix
+        elif self.interface.ip in client_b_prefix:
+            return target_b_prefix
+        else:
             raise ValueError(
-                f"Cannot determine the target-side network from {self.address}"
+                f"Cannot determine the target-side network from {self.interface}"
             )
-        return ipaddress.IPv4Network(f"100.127.{third_octet}.0/24")
 
     @property
     def address_with_prefix(self) -> str:

python/nova-understack/tests/test_nautobot_client.py

@@ -54,16 +54,16 @@ def test_network_property(self):
 
     def test_target_network_octet_0(self):
         """Test target_network calculation for third octet 0."""
-        ip = IPAddress.from_address_string("100.127.0.10/24")
+        ip = IPAddress.from_address_string("100.126.0.10/24")
 
-        expected_network = ipaddress.IPv4Network("100.127.0.0/24")
+        expected_network = ipaddress.IPv4Network("100.127.0.0/17")
         assert ip.target_network == expected_network
 
     def test_target_network_octet_128(self):
         """Test target_network calculation for third octet 128."""
-        ip = IPAddress.from_address_string("100.127.128.10/24")
+        ip = IPAddress.from_address_string("100.126.128.10/24")
 
-        expected_network = ipaddress.IPv4Network("100.127.128.0/24")
+        expected_network = ipaddress.IPv4Network("100.127.128.0/17")
         assert ip.target_network == expected_network
 
     def test_target_network_invalid_octet(self):
@@ -230,7 +230,7 @@ def test_as_openstack_network(self):
         """Test OpenStack network generation."""
         # Create IP with specific values for predictable gateway calculation
         ip_assignment = IPAddressAssignment(
-            ip_address=IPAddress.from_address_string("100.127.0.10/24")
+            ip_address=IPAddress.from_address_string("100.126.0.10/24")
         )
         interface = Interface(
             id="interface-1",
@@ -247,13 +247,13 @@ def test_as_openstack_network(self):
             "id": "network-for-if5",
             "type": "ipv4",
             "link": "tap-stor-5",
-            "ip_address": "100.127.0.10",
+            "ip_address": "100.126.0.10",
             "netmask": "255.255.255.0",
             "routes": [
                 {
                     "network": "100.127.0.0",
-                    "netmask": "255.255.255.0",
-                    "gateway": "100.127.0.1",
+                    "netmask": "255.255.128.0",
+                    "gateway": "100.126.0.1",
                 }
             ],
             "network_id": "test-network-id",
@@ -554,7 +554,7 @@ def test_generate_network_config_all_interfaces(self):
                     mac_address="aa:bb:cc:dd:ee:ff",
                     ip_address_assignments=[
                         IPAddressAssignment(
-                            ip_address=IPAddress.from_address_string("100.127.0.10/24")
+                            ip_address=IPAddress.from_address_string("100.126.0.10/24")
                         )
                     ],
                 ),
@@ -564,7 +564,7 @@ def test_generate_network_config_all_interfaces(self):
                     ip_address_assignments=[
                         IPAddressAssignment(
                             ip_address=IPAddress.from_address_string(
-                                "100.127.128.10/24"
+                                "100.126.128.10/24"
                             )
                         )
                     ],