Extract veth creation and LinkSetUp to net package

net/veth.go

@@ -0,0 +1,57 @@
+package net
+
+import (
+	"fmt"
+
+	"github.com/vishvananda/netlink"
+
+	"github.com/weaveworks/weave/common/odp"
+)
+
+// create and attach local name to the Weave bridge
+func CreateAndAttachVeth(localName, peerName, bridgeName string, mtu int) (*netlink.Veth, error) {
+	maybeBridge, err := netlink.LinkByName(bridgeName)
+	if err != nil {
+		return nil, fmt.Errorf(`bridge "%s" not present; did you launch weave?`, bridgeName)
+	}
+
+	if mtu == 0 {
+		mtu = maybeBridge.Attrs().MTU
+	}
+	local := &netlink.Veth{
+		LinkAttrs: netlink.LinkAttrs{
+			Name: localName,
+			MTU:  mtu},
+		PeerName: peerName,
+	}
+	if err := netlink.LinkAdd(local); err != nil {
+		return nil, fmt.Errorf(`could not create veth pair %s-%s: %s`, local.Name, local.PeerName, err)
+	}
+
+	switch maybeBridge.(type) {
+	case *netlink.Bridge:
+		if err := netlink.LinkSetMasterByIndex(local, maybeBridge.Attrs().Index); err != nil {
+			return nil, fmt.Errorf(`unable to set master of %s: %s`, local.Name, err)
+		}
+	case *netlink.GenericLink:
+		if maybeBridge.Type() != "openvswitch" {
+			return nil, fmt.Errorf(`device "%s" is of type "%s"`, bridgeName, maybeBridge.Type())
+		}
+		if err := odp.AddDatapathInterface(bridgeName, local.Name); err != nil {
+			return nil, fmt.Errorf(`failed to attach %s to device "%s": %s`, local.Name, bridgeName, err)
+		}
+	case *netlink.Device:
+		// Assume it's our openvswitch device, and the kernel has not been updated to report the kind.
+		if err := odp.AddDatapathInterface(bridgeName, local.Name); err != nil {
+			return nil, fmt.Errorf(`failed to attach %s to device "%s": %s`, local.Name, bridgeName, err)
+		}
+	default:
+		return nil, fmt.Errorf(`device "%s" is not a bridge`, bridgeName)
+	}
+
+	if err := netlink.LinkSetUp(local); err != nil {
+		return nil, fmt.Errorf("unable to bring veth up: %s", err)
+	}
+
+	return local, nil
+}

plugin/net/cni.go

@@ -15,6 +15,7 @@ import (
 	"github.com/vishvananda/netns"
 	weaveapi "github.com/weaveworks/weave/api"
 	"github.com/weaveworks/weave/common"
+	weavenet "github.com/weaveworks/weave/net"
 	ipamplugin "github.com/weaveworks/weave/plugin/ipam"
 )
 
@@ -70,7 +71,8 @@ func (c *CNIPlugin) CmdAdd(args *skel.CmdArgs) error {
 		id = fmt.Sprintf("%x", data)
 	}
 
-	local, err := createAndAttach(id, conf.BrName, conf.MTU)
+	name, peerName := vethPair(id)
+	local, err := weavenet.CreateAndAttachVeth(name, peerName, conf.BrName, conf.MTU)
 	if err != nil {
 		return err
 	}
@@ -87,10 +89,6 @@ func (c *CNIPlugin) CmdAdd(args *skel.CmdArgs) error {
 		return cleanup(fmt.Errorf("failed to move veth to container netns: %s", err))
 	}
 
-	if err := netlink.LinkSetUp(local); err != nil {
-		return cleanup(fmt.Errorf("unable to bring veth up: %s", err))
-	}
-
 	var result *types.Result
 	// Default IPAM is Weave's own
 	if conf.IPAM.Type == "" {

plugin/net/driver.go

@@ -11,7 +11,7 @@ import (
 	weaveapi "github.com/weaveworks/weave/api"
 	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/common/docker"
-	"github.com/weaveworks/weave/common/odp"
+	weavenet "github.com/weaveworks/weave/net"
 	"github.com/weaveworks/weave/plugin/skel"
 )
 
@@ -100,15 +100,12 @@ func (driver *driver) EndpointInfo(req *api.EndpointInfoRequest) (*api.EndpointI
 func (driver *driver) JoinEndpoint(j *api.JoinRequest) (*api.JoinResponse, error) {
 	driver.logReq("JoinEndpoint", j, fmt.Sprintf("%s:%s to %s", j.NetworkID, j.EndpointID, j.SandboxKey))
 
-	local, err := createAndAttach(j.EndpointID, WeaveBridge, 0)
+	name, peerName := vethPair(j.EndpointID)
+	local, err := weavenet.CreateAndAttachVeth(name, peerName, WeaveBridge, 0)
 	if err != nil {
 		return nil, driver.error("JoinEndpoint", "%s", err)
 	}
 
-	if err := netlink.LinkSetUp(local); err != nil {
-		return nil, driver.error("JoinEndpoint", "unable to bring up veth %s-%s: %s", local.Name, local.PeerName, err)
-	}
-
 	ifname := &api.InterfaceName{
 		SrcName:   local.PeerName,
 		DstPrefix: "ethwe",
@@ -128,50 +125,11 @@ func (driver *driver) JoinEndpoint(j *api.JoinRequest) (*api.JoinResponse, error
 	return response, nil
 }
 
-// create and attach local name to the Weave bridge
-func createAndAttach(id, bridgeName string, mtu int) (*netlink.Veth, error) {
-	maybeBridge, err := netlink.LinkByName(bridgeName)
-	if err != nil {
-		return nil, fmt.Errorf(`bridge "%s" not present; did you launch weave?`, bridgeName)
-	}
-
-	local := vethPair(id[:5])
-	if mtu == 0 {
-		local.Attrs().MTU = maybeBridge.Attrs().MTU
-	} else {
-		local.Attrs().MTU = mtu
-	}
-	if err := netlink.LinkAdd(local); err != nil {
-		return nil, fmt.Errorf(`could not create veth pair %s-%s: %s`, local.Name, local.PeerName, err)
-	}
-
-	switch maybeBridge.(type) {
-	case *netlink.Bridge:
-		if err := netlink.LinkSetMasterByIndex(local, maybeBridge.Attrs().Index); err != nil {
-			return nil, fmt.Errorf(`unable to set master of %s: %s`, local.Name, err)
-		}
-	case *netlink.GenericLink:
-		if maybeBridge.Type() != "openvswitch" {
-			return nil, fmt.Errorf(`device "%s" is of type "%s"`, bridgeName, maybeBridge.Type())
-		}
-		if err := odp.AddDatapathInterface(bridgeName, local.Name); err != nil {
-			return nil, fmt.Errorf(`failed to attach %s to device "%s": %s`, local.Name, bridgeName, err)
-		}
-	case *netlink.Device:
-		// Assume it's our openvswitch device, and the kernel has not been updated to report the kind.
-		if err := odp.AddDatapathInterface(bridgeName, local.Name); err != nil {
-			return nil, fmt.Errorf(`failed to attach %s to device "%s": %s`, local.Name, bridgeName, err)
-		}
-	default:
-		return nil, fmt.Errorf(`device "%s" is not a bridge`, bridgeName)
-	}
-	return local, nil
-}
-
 func (driver *driver) LeaveEndpoint(leave *api.LeaveRequest) error {
 	driver.logReq("LeaveEndpoint", leave, fmt.Sprintf("%s:%s", leave.NetworkID, leave.EndpointID))
 
-	local := vethPair(leave.EndpointID[:5])
+	name, _ := vethPair(leave.EndpointID)
+	local := &netlink.Veth{LinkAttrs: netlink.LinkAttrs{Name: name}}
 	if err := netlink.LinkDel(local); err != nil {
 		driver.warn("LeaveEndpoint", "unable to delete veth: %s", err)
 	}
@@ -188,13 +146,8 @@ func (driver *driver) DiscoverDelete(disco *api.DiscoveryNotification) error {
 	return nil
 }
 
-// ===
-
-func vethPair(suffix string) *netlink.Veth {
-	return &netlink.Veth{
-		LinkAttrs: netlink.LinkAttrs{Name: "vethwl" + suffix},
-		PeerName:  "vethwg" + suffix,
-	}
+func vethPair(id string) (string, string) {
+	return "vethwl" + id[:5], "vethwg" + id[:5]
 }
 
 // logging