Merge pull request #195 from SchSeba/l2-bridge

L2 bridge Implementation

plugins/main/bridge/README.md

@@ -28,6 +28,17 @@ If the bridge is missing, the plugin will create one on first use and, if gatewa
 }
 ```
 
+## Example L2-only configuration
+```
+{
+    "cniVersion": "0.3.1",
+	"name": "mynet",
+	"type": "bridge",
+	"bridge": "mynet0",
+	"ipam": {}
+}
+```
+
 ## Network configuration reference
 
 * `name` (string, required): the name of the network.
@@ -39,5 +50,5 @@ If the bridge is missing, the plugin will create one on first use and, if gatewa
 * `ipMasq` (boolean, optional): set up IP Masquerade on the host for traffic originating from this network and destined outside of it. Defaults to false.
 * `mtu` (integer, optional): explicitly set MTU to the specified value. Defaults to the value chosen by the kernel.
 * `hairpinMode` (boolean, optional): set hairpin mode for interfaces on the bridge. Defaults to false.
-* `ipam` (dictionary, required): IPAM configuration to be used for this network.
+* `ipam` (dictionary, required): IPAM configuration to be used for this network. For L2-only network, create empty dictionary.
 * `promiscMode` (boolean, optional): set promiscuous mode on the bridge. Defaults to false.

plugins/main/bridge/bridge.go

@@ -334,6 +334,8 @@ func cmdAdd(args *skel.CmdArgs) error {
 		return err
 	}
 
+	isLayer3 := n.IPAM.Type != ""
+
 	if n.IsDefaultGW {
 		n.IsGW = true
 	}
@@ -358,6 +360,10 @@ func cmdAdd(args *skel.CmdArgs) error {
 		return err
 	}
 
+	// Assume L2 interface only
+	result := &current.Result{CNIVersion: cniVersion, Interfaces: []*current.Interface{brInterface, hostInterface, containerInterface}}
+
+	if isLayer3 {
 		// run the IPAM plugin and get back the config to apply
 		r, err := ipam.ExecAdd(n.IPAM.Type, args.StdinData)
 		if err != nil {
@@ -374,17 +380,18 @@ func cmdAdd(args *skel.CmdArgs) error {
 		}()
 
 		// Convert whatever the IPAM result was into the current Result type
-	result, err := current.NewResultFromResult(r)
+		ipamResult, err := current.NewResultFromResult(r)
 		if err != nil {
 			return err
 		}
 
+		result.IPs = ipamResult.IPs
+		result.Routes = ipamResult.Routes
+
 		if len(result.IPs) == 0 {
 			return errors.New("IPAM plugin returned missing IP config")
 		}
 
-	result.Interfaces = []*current.Interface{brInterface, hostInterface, containerInterface}
-
 		// Gather gateway information for each IP family
 		gwsV4, gwsV6, err := calcGateways(result, n)
 		if err != nil {
@@ -458,6 +465,7 @@ func cmdAdd(args *skel.CmdArgs) error {
 				}
 			}
 		}
+	}
 
 	// Refetch the bridge since its MAC address may change when the first
 	// veth is added or after its IP address is set
@@ -485,9 +493,13 @@ func cmdDel(args *skel.CmdArgs) error {
 		return err
 	}
 
+	isLayer3 := n.IPAM.Type != ""
+
+	if isLayer3 {
 		if err := ipam.ExecDel(n.IPAM.Type, args.StdinData); err != nil {
 			return err
 		}
+	}
 
 	if args.Netns == "" {
 		return nil
@@ -510,7 +522,7 @@ func cmdDel(args *skel.CmdArgs) error {
 		return err
 	}
 
-	if n.IPMasq {
+	if isLayer3 && n.IPMasq {
 		chain := utils.FormatChainName(n.Name, args.ContainerID)
 		comment := utils.FormatComment(n.Name, args.ContainerID)
 		for _, ipn := range ipnets {

plugins/main/bridge/bridge_test.go

@@ -47,6 +47,7 @@ type testCase struct {
 	gateway    string      // Single subnet config: Gateway
 	ranges     []rangeInfo // Ranges list (multiple subnets config)
 	isGW       bool
+	isLayer2   bool
 	expGWCIDRs []string // Expected gateway addresses in CIDR form
 }
 
@@ -77,7 +78,9 @@ const (
 	"cniVersion": "%s",
 	"name": "testConfig",
 	"type": "bridge",
-	"bridge": "%s",
+	"bridge": "%s",`
+
+	netDefault = `
 	"isDefaultGateway": true,
 	"ipMasq": false`
 
@@ -117,6 +120,8 @@ const (
 // for a test case.
 func (tc testCase) netConfJSON(dataDir string) string {
 	conf := fmt.Sprintf(netConfStr, tc.cniVersion, BRNAME)
+	if !tc.isLayer2 {
+		conf += netDefault
 		if tc.subnet != "" || tc.ranges != nil {
 			conf += ipamStartStr
 			if dataDir != "" {
@@ -130,6 +135,10 @@ func (tc testCase) netConfJSON(dataDir string) string {
 			}
 			conf += ipamEndStr
 		}
+	} else {
+		conf += `
+	"ipam": {}`
+	}
 	return "{" + conf + "\n}"
 }
 
@@ -336,7 +345,10 @@ func (tester *testerV03x) cmdAddTest(tc testCase, dataDir string) {
 		// Check that the bridge has a different mac from the veth
 		// If not, it means the bridge has an unstable mac and will change
 		// as ifs are added and removed
+		// this check is not relevant for a layer 2 bridge
+		if !tc.isLayer2 {
 			Expect(link.Attrs().HardwareAddr.String()).NotTo(Equal(bridgeMAC))
+		}
 
 		return nil
 	})
@@ -700,6 +712,16 @@ var _ = Describe("bridge Operations", func() {
 		}
 	})
 
+	It("configures and deconfigures a l2 bridge and veth with ADD/DEL for 0.3.1 config", func() {
+		tc := testCase{cniVersion: "0.3.0", isLayer2: true}
+		cmdAddDelTest(originalNS, tc, dataDir)
+	})
+
+	It("configures and deconfigures a l2 bridge and veth with ADD/DEL for 0.3.1 config", func() {
+		tc := testCase{cniVersion: "0.3.1", isLayer2: true}
+		cmdAddDelTest(originalNS, tc, dataDir)
+	})
+
 	It("configures and deconfigures a bridge and veth with default route with ADD/DEL for 0.3.1 config", func() {
 		testCases := []testCase{
 			{