From 31615a854c5e46a05087a1d8033e7cb9665d1709 Mon Sep 17 00:00:00 2001
From: Ghislain Bourgeois <ghislain.bourgeois@canonical.com>
Date: Fri, 23 Aug 2024 08:25:03 -0400
Subject: [PATCH] fix: Add MTU to NAD when using DPDK (#341)

---
 src/charm.py             | 28 ++++++++++++++++------------
 tests/unit/test_charm.py | 29 +++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/src/charm.py b/src/charm.py
index ae19f83..b425448 100755
--- a/src/charm.py
+++ b/src/charm.py
@@ -307,16 +307,14 @@ def _create_nad_from_config(self, interface_name: str) -> NetworkAttachmentDefin
         Returns:
             NetworkAttachmentDefinition: NetworkAttachmentDefinition object
         """
-        nad_config = self._get_nad_base_config()
-        cni_type = self._charm_config.cni_type
-        # MTU is optional for bridge, macvlan, dpdk
-        # MTU is ignored by host-device
-        if cni_type != CNIType.host_device:
-            if interface_mtu := self._get_interface_mtu_config(interface_name):
-                nad_config.update({"mtu": interface_mtu})
+        nad_config = self._get_nad_base_config(interface_name)
+
         nad_config["ipam"].update(
             {"addresses": [{"address": self._get_network_ip_config(interface_name)}]}
         )
+
+        cni_type = self._charm_config.cni_type
+
         # host interface name is used only by macvlan and host-device
         if host_interface := self._get_interface_config(interface_name):
             if cni_type == CNIType.macvlan:
@@ -352,7 +350,7 @@ def _create_dpdk_access_nad_from_config(self) -> NetworkAttachmentDefinition:
         Returns:
             NetworkAttachmentDefinition: NetworkAttachmentDefinition object
         """
-        access_nad_config = self._get_nad_base_config()
+        access_nad_config = self._get_nad_base_config(ACCESS_INTERFACE_NAME)
         access_nad_config.update({"type": "vfioveth"})
 
         return NetworkAttachmentDefinition(
@@ -371,7 +369,7 @@ def _create_dpdk_core_nad_from_config(self) -> NetworkAttachmentDefinition:
         Returns:
             NetworkAttachmentDefinition: NetworkAttachmentDefinition object
         """
-        core_nad_config = self._get_nad_base_config()
+        core_nad_config = self._get_nad_base_config(CORE_INTERFACE_NAME)
         core_nad_config.update({"type": "vfioveth"})
 
         return NetworkAttachmentDefinition(
@@ -384,8 +382,7 @@ def _create_dpdk_core_nad_from_config(self) -> NetworkAttachmentDefinition:
             spec={"config": json.dumps(core_nad_config)},
         )
 
-    @staticmethod
-    def _get_nad_base_config() -> Dict[Any, Any]:
+    def _get_nad_base_config(self, interface_name: str) -> Dict[Any, Any]:
         """Get the base NetworkAttachmentDefinition.
 
         This config is extended according to charm config.
@@ -393,13 +390,20 @@ def _get_nad_base_config() -> Dict[Any, Any]:
         Returns:
             config (dict): Base NAD config
         """
-        return {
+        base_nad = {
             "cniVersion": "0.3.1",
             "ipam": {
                 "type": "static",
             },
             "capabilities": {"mac": True},
         }
+        cni_type = self._charm_config.cni_type
+        # MTU is optional for bridge, macvlan, dpdk
+        # MTU is ignored by host-device
+        if cni_type != CNIType.host_device:
+            if interface_mtu := self._get_interface_mtu_config(interface_name):
+                base_nad.update({"mtu": interface_mtu})
+        return base_nad
 
     def _write_upf_config_file_to_bessd_container(self, content: str) -> None:
         push_file(
diff --git a/tests/unit/test_charm.py b/tests/unit/test_charm.py
index 1404b3c..1e281bc 100644
--- a/tests/unit/test_charm.py
+++ b/tests/unit/test_charm.py
@@ -1188,6 +1188,35 @@ def _get_create_core_nad_call(mock_call):
             DPDK_CORE_INTERFACE_RESOURCE_NAME in nad_annotations["k8s.v1.cni.cncf.io/resourceName"]
         )
 
+    def test_given_upf_configured_to_run_in_dpdk_mode_and_mtu_is_set_when_create_network_attachment_definitions_then_nads_have_mtu_specified(  # noqa: E501
+        self, set_can_connect_containers, enable_huge_pages_multus_and_dpdk
+    ):
+        self.mock_running_service()
+        self.mock_client_list.side_effect = [
+            [Node(status=NodeStatus(allocatable={"hugepages-1Gi": "3Gi"}))],
+            [Node(status=NodeStatus(allocatable={"hugepages-1Gi": "3Gi"}))],
+            [],
+            [],
+            [],
+        ]
+        self.harness.update_config(
+            key_values={
+                "cni-type": "vfioveth",
+                "upf-mode": "dpdk",
+                "access-interface-mac-address": VALID_ACCESS_MAC,
+                "core-interface-mac-address": VALID_CORE_MAC,
+                "access-interface-mtu-size": 9000,
+                "core-interface-mtu-size": 9000,
+            }
+        )
+
+        nads = self.harness.charm._network_attachment_definitions_from_config()
+        for nad in nads:
+            assert nad.spec
+            config = json.loads(nad.spec["config"])
+            assert "mtu" in config
+            assert config["mtu"] == 9000
+
     def test_given_upf_charm_configured_to_run_in_default_mode_when_patch_statefulset_then_2_network_annotations_are_created(  # noqa: E501
         self, set_can_connect_containers, enable_huge_pages_multus_and_dpdk
     ):