Support reading OvnPort from args.cni

pkg/plugin/plugin.go

@@ -277,6 +277,17 @@ func CmdAdd(args *skel.CmdArgs) error {
 		return err
 	}
 
+	// Check for OvnPort and MAC in args.cni (CNI convention)
+	// args.cni takes precedence over CNI_ARGS per CNI spec
+	if netconf.Args != nil && netconf.Args.CNI != nil {
+		if netconf.Args.CNI.OvnPort != "" {
+			ovnPort = netconf.Args.CNI.OvnPort
+		}
+		if netconf.Args.CNI.MAC != "" {
+			mac = netconf.Args.CNI.MAC
+		}
+	}
+
 	var vlanTagNum uint = 0
 	trunks := make([]uint, 0)
 	portType := "access"
@@ -558,6 +569,12 @@ func CmdDel(args *skel.CmdArgs) error {
 	if envArgs != nil {
 		ovnPort = string(envArgs.OvnPort)
 	}
+	// Check for OvnPort in args.cni (CNI convention) - takes precedence
+	if cache.Netconf.Args != nil && cache.Netconf.Args.CNI != nil {
+		if cache.Netconf.Args.CNI.OvnPort != "" {
+			ovnPort = cache.Netconf.Args.CNI.OvnPort
+		}
+	}
 	ovsDriver, err := ovsdb.NewOvsDriver(cache.Netconf.SocketFile)
 	if err != nil {
 		return err
@@ -679,6 +696,12 @@ func CmdCheck(args *skel.CmdArgs) error {
 	if envArgs != nil {
 		ovnPort = string(envArgs.OvnPort)
 	}
+	// Check for OvnPort in args.cni (CNI convention) - takes precedence
+	if netconf.Args != nil && netconf.Args.CNI != nil {
+		if netconf.Args.CNI.OvnPort != "" {
+			ovnPort = netconf.Args.CNI.OvnPort
+		}
+	}
 	ovsDriver, err := ovsdb.NewOvsDriver(netconf.SocketFile)
 	if err != nil {
 		return err

pkg/plugin/plugin_test.go

@@ -735,6 +735,70 @@ var testFunc = func(version string) {
 				Expect(string(output[:len(output)-1])).To(Equal(ovsOutput))
 			})
 		})
+		Context("specified OvnPort via args.cni", func() {
+			It("should successfully complete ADD, CHECK and DEL commands with args.cni OvnPort", func() {
+				const ovsOutput = "external_ids        : {iface-id=test-port-from-args}"
+
+				// OvnPort specified in args.cni (CNI convention) instead of CNI_ARGS
+				conf := fmt.Sprintf(`{
+				"cniVersion": "%s",
+				"name": "mynet",
+				"type": "ovs",
+				"bridge": "%s",
+				"args": {
+					"cni": {
+						"OvnPort": "test-port-from-args"
+					}
+				}}`, version, bridgeName)
+
+				targetNs := newNS()
+				defer func() {
+					closeNS(targetNs)
+				}()
+
+				By("Calling ADD command with args.cni OvnPort")
+				hostIfName, result := testAdd(conf, false, false, "", targetNs)
+				hostIface := result.(*current.Result).Interfaces[0]
+
+				By("Verifying iface-id was set from args.cni")
+				output, err := exec.Command("ovs-vsctl", "--column=external_ids", "find", "Interface", fmt.Sprintf("name=%s", hostIface.Name)).CombinedOutput()
+				Expect(err).NotTo(HaveOccurred())
+				Expect(string(output[:len(output)-1])).To(Equal(ovsOutput))
+
+				By("Calling CHECK command")
+				testCheck(conf, result, targetNs)
+
+				By("Calling DEL command")
+				testDel(conf, hostIfName, targetNs, true)
+			})
+			It("should prefer args.cni OvnPort over CNI_ARGS", func() {
+				// args.cni should take precedence per CNI conventions
+				const ovsOutput = "external_ids        : {iface-id=args-cni-port}"
+
+				conf := fmt.Sprintf(`{
+				"cniVersion": "%s",
+				"name": "mynet",
+				"type": "ovs",
+				"bridge": "%s",
+				"args": {
+					"cni": {
+						"OvnPort": "args-cni-port"
+					}
+				}}`, version, bridgeName)
+
+				targetNs := newNS()
+				defer func() {
+					closeNS(targetNs)
+				}()
+
+				// Pass a different ovnPort via CNI_ARGS - args.cni should win
+				result := attach(targetNs, conf, IFNAME, "", "cni-args-port")
+				hostIface := result.Interfaces[0]
+				output, err := exec.Command("ovs-vsctl", "--column=external_ids", "find", "Interface", fmt.Sprintf("name=%s", hostIface.Name)).CombinedOutput()
+				Expect(err).NotTo(HaveOccurred())
+				Expect(string(output[:len(output)-1])).To(Equal(ovsOutput))
+			})
+		})
 		Context("specified OfportRequest", func() {
 			It("should configure an ovs interface with a specific ofport", func() {
 				// Pick a random ofport 5000-6000

pkg/types/types.go

@@ -26,6 +26,13 @@ type NetConfs interface {
 	NetConf | MirrorNetConf
 }
 
+// CNIArgs contains arguments passed via args.cni in the CNI config
+// This follows CNI conventions: https://www.cni.dev/docs/conventions/
+type CNIArgs struct {
+	OvnPort string `json:"OvnPort,omitempty"`
+	MAC     string `json:"MAC,omitempty"`
+}
+
 // NetConf extends types.NetConf for ovs-cni
 type NetConf struct {
 	types.NetConf
@@ -40,6 +47,10 @@ type NetConf struct {
 	SocketFile             string   `json:"socket_file"`
 	LinkStateCheckRetries  int      `json:"link_state_check_retries"`
 	LinkStateCheckInterval int      `json:"link_state_check_interval"`
+	// Args contains CNI args passed via args.cni in the config
+	Args *struct {
+		CNI *CNIArgs `json:"cni,omitempty"`
+	} `json:"args,omitempty"`
 }
 
 // MirrorNetConf extends types.NetConf for ovs-mirrors

pkg/types/types_test.go

@@ -0,0 +1,110 @@
+// Copyright (c) 2026 VEXXHOST, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package types
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestNetConfArgsCNIParsing(t *testing.T) {
+	tests := []struct {
+		name           string
+		config         string
+		expectedOvnPort string
+		expectedMAC    string
+	}{
+		{
+			name: "args.cni with OvnPort",
+			config: `{
+				"cniVersion": "1.0.0",
+				"name": "test-net",
+				"type": "ovs",
+				"bridge": "br-int",
+				"args": {
+					"cni": {
+						"OvnPort": "test-port-id"
+					}
+				}
+			}`,
+			expectedOvnPort: "test-port-id",
+			expectedMAC:    "",
+		},
+		{
+			name: "args.cni with OvnPort and MAC",
+			config: `{
+				"cniVersion": "1.0.0",
+				"name": "test-net",
+				"type": "ovs",
+				"bridge": "br-int",
+				"args": {
+					"cni": {
+						"OvnPort": "my-ovn-port",
+						"MAC": "fa:16:3e:aa:bb:cc"
+					}
+				}
+			}`,
+			expectedOvnPort: "my-ovn-port",
+			expectedMAC:    "fa:16:3e:aa:bb:cc",
+		},
+		{
+			name: "no args section",
+			config: `{
+				"cniVersion": "1.0.0",
+				"name": "test-net",
+				"type": "ovs",
+				"bridge": "br-int"
+			}`,
+			expectedOvnPort: "",
+			expectedMAC:    "",
+		},
+		{
+			name: "empty args.cni",
+			config: `{
+				"cniVersion": "1.0.0",
+				"name": "test-net",
+				"type": "ovs",
+				"bridge": "br-int",
+				"args": {
+					"cni": {}
+				}
+			}`,
+			expectedOvnPort: "",
+			expectedMAC:    "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var netconf NetConf
+			if err := json.Unmarshal([]byte(tt.config), &netconf); err != nil {
+				t.Fatalf("Failed to unmarshal config: %v", err)
+			}
+
+			var gotOvnPort, gotMAC string
+			if netconf.Args != nil && netconf.Args.CNI != nil {
+				gotOvnPort = netconf.Args.CNI.OvnPort
+				gotMAC = netconf.Args.CNI.MAC
+			}
+
+			if gotOvnPort != tt.expectedOvnPort {
+				t.Errorf("OvnPort = %q, want %q", gotOvnPort, tt.expectedOvnPort)
+			}
+			if gotMAC != tt.expectedMAC {
+				t.Errorf("MAC = %q, want %q", gotMAC, tt.expectedMAC)
+			}
+		})
+	}
+}