tap: allow for a tap device to be created as a bridge port

plugins/main/tap/tap.go

@@ -47,6 +47,7 @@ type NetConf struct {
 	Owner          *uint32   `json:"owner,omitempty"`
 	Group          *uint32   `json:"group,omitempty"`
 	SelinuxContext string    `json:"selinuxContext,omitempty"`
+	Bridge         string    `json:"bridge,omitempty"`
 	Args           *struct{} `json:"args,omitempty"`
 	RuntimeConfig  struct {
 		Mac string `json:"mac,omitempty"`
@@ -216,6 +217,18 @@ func createTap(conf *NetConf, ifName string, netns ns.NetNS) (*current.Interface
 			return fmt.Errorf("failed to refetch tap %q: %v", ifName, err)
 		}
 
+		if conf.Bridge != "" {
+			bridge, err := netlink.LinkByName(conf.Bridge)
+			if err != nil {
+				return fmt.Errorf("failed to get bridge %s: %v", conf.Bridge, err)
+			}
+
+			tapDev := link
+			if err := netlink.LinkSetMaster(tapDev, bridge); err != nil {
+				return fmt.Errorf("failed to set tap %s as a port of bridge %s: %v", tap.Name, conf.Bridge, err)
+			}
+		}
+
 		err = netlink.LinkSetUp(link)
 		if err != nil {
 			return fmt.Errorf("failed to set tap interface up: %v", err)

plugins/main/tap/tap_test.go

@@ -314,5 +314,120 @@ var _ = Describe("Add, check, remove tap plugin", func() {
 			Expect(err).NotTo(HaveOccurred())
 		})
 
+		It(fmt.Sprintf("[%s] add, check and remove a tap device as a bridge port", ver), func() {
+			const bridgeName = "br1"
+			conf := fmt.Sprintf(`{
+				    "cniVersion": "%s",
+				    "name": "tapTest",
+				    "type": "tap",
+				    "owner": 0,
+				    "group": 0,
+                    "bridge": %q,
+				    "ipam": {
+						"type": "host-local",
+						"subnet": "10.1.2.0/24",
+						"dataDir": "%s"
+				    }
+				}`, ver, bridgeName, dataDir)
+
+			args := &skel.CmdArgs{
+				ContainerID: "dummy",
+				Netns:       targetNS.Path(),
+				IfName:      IFNAME,
+				StdinData:   []byte(conf),
+			}
+
+			t := newTesterByVersion(ver)
+
+			var bridge netlink.Link
+			var result types.Result
+			var macAddress string
+			var err error
+
+			Expect(
+				targetNS.Do(func(ns.NetNS) error {
+					if err := netlink.LinkAdd(&netlink.Bridge{
+						LinkAttrs: netlink.LinkAttrs{
+							Name: bridgeName,
+						},
+					}); err != nil {
+						return err
+					}
+					bridge, err = netlink.LinkByName(bridgeName)
+					if err != nil {
+						return err
+					}
+					return nil
+				}),
+			).To(Succeed())
+
+			err = originalNS.Do(func(ns.NetNS) error {
+				defer GinkgoRecover()
+
+				result, _, err = testutils.CmdAddWithArgs(args, func() error {
+					return cmdAdd(args)
+				})
+				Expect(err).NotTo(HaveOccurred())
+				macAddress = t.verifyResult(result, IFNAME)
+				return nil
+			})
+			Expect(err).NotTo(HaveOccurred())
+
+			By("Make sure the tap link exists in the target namespace")
+			err = targetNS.Do(func(ns.NetNS) error {
+				defer GinkgoRecover()
+
+				link, err := netlink.LinkByName(IFNAME)
+				Expect(err).NotTo(HaveOccurred())
+				Expect(link.Attrs().Name).To(Equal(IFNAME))
+				Expect(link.Type()).To(Equal(TYPETAP))
+				Expect(link.Attrs().MasterIndex).To(Equal(bridge.Attrs().Index))
+
+				if macAddress != "" {
+					hwaddr, err := net.ParseMAC(macAddress)
+					Expect(err).NotTo(HaveOccurred())
+					Expect(link.Attrs().HardwareAddr).To(Equal(hwaddr))
+				}
+				addrs, err := netlink.AddrList(link, syscall.AF_INET)
+				Expect(err).NotTo(HaveOccurred())
+				Expect(addrs).To(HaveLen(1))
+				return nil
+			})
+			Expect(err).NotTo(HaveOccurred())
+
+			By("Running cmdDel")
+			args.StdinData = []byte(conf)
+			err = originalNS.Do(func(ns.NetNS) error {
+				defer GinkgoRecover()
+
+				err = testutils.CmdDelWithArgs(args, func() error {
+					return cmdDel(args)
+				})
+				Expect(err).NotTo(HaveOccurred())
+				return nil
+			})
+			Expect(err).NotTo(HaveOccurred())
+
+			err = targetNS.Do(func(ns.NetNS) error {
+				defer GinkgoRecover()
+
+				link, err := netlink.LinkByName(IFNAME)
+				Expect(err).To(HaveOccurred())
+				Expect(link).To(BeNil())
+				return nil
+			})
+			Expect(err).NotTo(HaveOccurred())
+
+			By("Running cmdDel more than once without error")
+			err = originalNS.Do(func(ns.NetNS) error {
+				defer GinkgoRecover()
+				err = testutils.CmdDelWithArgs(args, func() error {
+					return cmdDel(args)
+				})
+				Expect(err).NotTo(HaveOccurred())
+				return nil
+			})
+			Expect(err).NotTo(HaveOccurred())
+		})
 	}
 })