cni: add promiscous mode knob

Signed-off-by: Miguel Duarte Barroso <[email protected]>

README.md

@@ -105,6 +105,8 @@ The CNI config json allows the following parameters:
 * `deviceID` (string, required): name of an existing macvtap host interface, which
   will be moved to the correct net namespace and configured. Optional when used within a
   NetworkAttachmentDefinition, as Multus provides the deviceID in that case.
+* `promiscMode` (bool, optional): enable promiscous mode on the pod side of the
+  veth. Defaults to false.
 
 A pod can be attached to that network which would result in the pod having the corresponding
 macvtap interface:

pkg/cni/plugin.go

@@ -33,8 +33,9 @@ import (
 // A NetConf structure represents a Multus network attachment definition configuration
 type NetConf struct {
 	types.NetConf
-	DeviceID string `json:"deviceID"`
-	MTU      int    `json:"mtu,omitempty"`
+	DeviceID      string `json:"deviceID"`
+	MTU           int    `json:"mtu,omitempty"`
+	IsPromiscuous bool   `json:"promiscMode,omitempty"`
 }
 
 // EnvArgs structure represents inputs sent from each VMI via environment variables
@@ -103,7 +104,7 @@ func CmdAdd(args *skel.CmdArgs) error {
 		}
 	}()
 
-	macvtapInterface, err := util.ConfigureInterface(netConf.DeviceID, args.IfName, mac, netConf.MTU, netns)
+	macvtapInterface, err := util.ConfigureInterface(netConf.DeviceID, args.IfName, mac, netConf.MTU, netConf.IsPromiscuous, netns)
 	if err != nil {
 		return err
 	}

pkg/cni/plugin_test.go

@@ -211,5 +211,46 @@ var _ = Describe("Macvtap CNI", func() {
 				})
 			})
 		})
+
+		When("importing a macvtap interface into the target netns with promiscous mode enabled", func() {
+			BeforeEach(func() {
+				promiscousModeArgs := fmt.Sprintf(`{
+				"cniVersion": "0.3.1",
+				"name": "mynet",
+				"type": "macvtap",
+				"deviceID": "%s",
+				"promiscMode": true
+			}`, deviceID)
+				args := &skel.CmdArgs{
+					ContainerID: "dummy",
+					Netns:       targetNs.Path(),
+					IfName:      deviceID,
+					StdinData:   []byte(promiscousModeArgs),
+				}
+
+				originalNS.Do(func(ns.NetNS) error {
+					defer GinkgoRecover()
+
+					_, _, err := testutils.CmdAdd(args.Netns, args.ContainerID, args.IfName, args.StdinData, func() error { return cni.CmdAdd(args) })
+					Expect(err).NotTo(HaveOccurred())
+
+					return nil
+				})
+			})
+
+			It("SHOULD successfully import the macvtap interface into the target netns, having the link promisc mode enabled", func() {
+				// confirm macvtap is available on target namespace, and the correct configurations were applied
+				targetNs.Do(func(ns.NetNS) error {
+					const enabled = 1
+					defer GinkgoRecover()
+
+					link, err := netlink.LinkByName(deviceID)
+					Expect(err).NotTo(HaveOccurred())
+					Expect(link.Attrs().Promisc).To(Equal(enabled))
+
+					return nil
+				})
+			})
+		})
 	})
 })

pkg/util/netlink.go

@@ -227,7 +227,7 @@ func onLinkEvent(match func(netlink.Link) bool, nsPath string, do func(), stop <
 
 // Move an existing macvtap interface from the current netns to the target netns, and rename it..
 // Optionally configure the MAC address of the interface and the link's MTU.
-func ConfigureInterface(currentIfaceName string, newIfaceName string, macAddr *net.HardwareAddr, mtu int, netns ns.NetNS) (*current.Interface, error) {
+func ConfigureInterface(currentIfaceName string, newIfaceName string, macAddr *net.HardwareAddr, mtu int, promisc bool, netns ns.NetNS) (*current.Interface, error) {
 	var err error
 
 	macvtapIface, err := netlink.LinkByName(currentIfaceName)
@@ -263,6 +263,12 @@ func ConfigureInterface(currentIfaceName string, newIfaceName string, macAddr *n
 			}
 		}
 
+		if promisc {
+			if err := netlink.SetPromiscOn(macvtapIface); err != nil {
+				return fmt.Errorf("failed to enable promiscous mode on %q: %v", currentIfaceName, err)
+			}
+		}
+
 		renamedMacvtapIface, err := renameInterface(macvtapIface, newIfaceName)
 		if err != nil {
 			return err