removed subshelling from veth between containers

clab/netlink.go

@@ -4,13 +4,14 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"os/exec"
+	"runtime"
 	"strings"
 	"sync"
 
 	"github.com/google/uuid"
 	log "github.com/sirupsen/logrus"
 	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netns"
 )
 
 func (c *cLab) InitVirtualWiring() {
@@ -51,23 +52,30 @@ func (c *cLab) createAToBveth(l *Link) error {
 	interfaceA := fmt.Sprintf("clab-%s", genIfName())
 	interfaceB := fmt.Sprintf("clab-%s", genIfName())
 
-	cmd := exec.Command("sudo", "ip", "link", "add", interfaceA, "type", "veth", "peer", "name", interfaceB)
-	err := runCmd(cmd)
+	nllA := &netlink.Veth{PeerName: interfaceB, LinkAttrs: netlink.LinkAttrs{Name: interfaceA}}
+
+	err := netlink.LinkAdd(nllA)
 	if err != nil {
 		return err
 	}
+
 	wg := new(sync.WaitGroup)
 	wg.Add(2)
 	go func() {
 		defer wg.Done()
-		err := c.configVeth(interfaceA, l.A.EndpointName, l.A.Node.LongName)
+		la := c.newLinkAttributes()
+		la.Name = l.A.EndpointName
+		err = c.configVeth(interfaceA, la, l.A.Node.LongName)
 		if err != nil {
 			log.Fatalf("failed to config interface '%s' in container %s: %v", l.A.EndpointName, l.A.Node.LongName, err)
 		}
 	}()
 	go func() {
 		defer wg.Done()
-		err = c.configVeth(interfaceB, l.B.EndpointName, l.B.Node.LongName)
+
+		la := c.newLinkAttributes()
+		la.Name = l.B.EndpointName
+		err = c.configVeth(interfaceB, la, l.B.Node.LongName)
 		if err != nil {
 			log.Fatalf("failed to config interface '%s' in container %s: %v", l.B.EndpointName, l.B.Node.LongName, err)
 		}
@@ -76,36 +84,128 @@ func (c *cLab) createAToBveth(l *Link) error {
 	return nil
 }
 
-func (c *cLab) configVeth(dummyInterface, endpointName, ns string) error {
-	var cmd *exec.Cmd
+// LinkAttributes Type for the adjustment of the Link Attributes
+type LinkAttributes struct {
+	Name   string
+	MTU    int
+	LinkUp bool
+	// Master is just used for interfaces meant to be attached to bridges
+	Master string
+}
+
+// Initialize and instantiate a new LinkAttributes with default values
+func (c *cLab) newLinkAttributes() LinkAttributes {
+	return LinkAttributes{Name: "", MTU: 1500, LinkUp: true, Master: ""}
+}
+
+func (c *cLab) configVeth(dummyInterface string, la LinkAttributes, ns string) error {
+
+	netNS, err := netns.GetFromName(ns)
+	if err != nil {
+		return err
+	}
+
 	log.Debugf("Disabling TX checksum offloading for the %s interface...", dummyInterface)
-	err := EthtoolTXOff(dummyInterface)
+	err = EthtoolTXOff(dummyInterface)
+	if err != nil {
+		return err
+	}
+
+	netLink, err := netlink.LinkByName(dummyInterface)
 	if err != nil {
 		return err
 	}
+
 	log.Debugf("map dummy interface '%s' to container %s", dummyInterface, ns)
-	cmd = exec.Command("sudo", "ip", "link", "set", dummyInterface, "netns", ns)
-	err = runCmd(cmd)
+	err = netlink.LinkSetNsFd(netLink, int(netNS))
 	if err != nil {
 		return err
 	}
-	log.Debugf("rename interface %s to %s", dummyInterface, endpointName)
-	cmd = exec.Command("sudo", "ip", "netns", "exec", ns, "ip", "link", "set", dummyInterface, "name", endpointName)
-	err = runCmd(cmd)
+
+	err = c.setLinkAttributes(ns, netNS, dummyInterface, la)
 	if err != nil {
 		return err
 	}
-	log.Debugf("set interface %s state to up in NS %s", endpointName, ns)
-	cmd = exec.Command("sudo", "ip", "netns", "exec", ns, "ip", "link", "set", endpointName, "up")
-	err = runCmd(cmd)
+	return nil
+
+}
+
+func (c *cLab) setLinkAttributes(namespaceName string, cnamespace netns.NsHandle, oldLinkName string, la LinkAttributes) error {
+	hostNetNs, _ := netns.Get()
+	netns.Set(cnamespace)
+	runtime.LockOSThread()
+
+	link, err := netlink.LinkByName(oldLinkName)
 	if err != nil {
 		return err
 	}
+	if la.Name != "" {
+		log.Debugf("rename interface %s to %s", oldLinkName, la.Name)
+		err = netlink.LinkSetName(link, la.Name)
+		if err != nil {
+			return err
+		}
+	}
+	if la.LinkUp {
+		log.Debugf("set interface %s state to up in NS %s", la.Name, namespaceName)
+		err = netlink.LinkSetUp(link)
+		if err != nil {
+			return err
+		}
+	}
+	if la.Master != "" {
+		// if interface should be attached to a bridge, the Master is set to bridge name
+		log.Debugf("attache interface %s to bridge %s", la.Name, la.Master)
+
+		parentIndex := link.Attrs().ParentIndex
+
+		runtime.UnlockOSThread()
+		netns.Set(hostNetNs)
+		runtime.LockOSThread()
+
+		// get handleto master link
+		rootNSvethLink, err := netlink.LinkByIndex(parentIndex)
+		if err != nil {
+			return err
+		}
+
+		bridgeIf, err := netlink.LinkByName(la.Master)
+		if err != nil {
+			return err
+		}
+
+		// assigne master for link
+		err = netlink.LinkSetMaster(rootNSvethLink, bridgeIf)
+		if err != nil {
+			return err
+		}
+
+		// Finally set rootNSvethLink interface up
+		err = netlink.LinkSetUp(rootNSvethLink)
+		if err != nil {
+			return err
+		}
+
+		log.Debugf("setting root-ns interface %s MTU to %d", la.Name, la.MTU)
+		netlink.LinkSetMTU(rootNSvethLink, la.MTU)
+		if err != nil {
+			return err
+		}
+		runtime.UnlockOSThread()
+		netns.Set(cnamespace)
+		runtime.LockOSThread()
+	}
+	log.Debugf("setting interface %s MTU to %d", la.Name, la.MTU)
+	netlink.LinkSetMTU(link, la.MTU)
+	if err != nil {
+		return err
+	}
+	runtime.UnlockOSThread()
+	netns.Set(hostNetNs)
 	return nil
 }
 
 func (c *cLab) createvethToBridge(l *Link) error {
-	var cmd *exec.Cmd
 	var err error
 	log.Debugf("Create veth to bridge wire: %s <--> %s", l.A.EndpointName, l.B.EndpointName)
 	dummyIface := fmt.Sprintf("clab-%s", genIfName())
@@ -125,27 +225,21 @@ func (c *cLab) createvethToBridge(l *Link) error {
 	}
 
 	log.Debugf("create dummy veth pair '%s'<-->'%s'", dummyIface, bridgeIfname)
-	cmd = exec.Command("sudo", "ip", "link", "add", dummyIface, "type", "veth", "peer", "name", bridgeIfname)
-	err = runCmd(cmd)
-	if err != nil {
-		return err
-	}
-	err = c.configVeth(dummyIface, containerIfName, containerNS)
-	if err != nil {
-		return err
-	}
-	log.Debugf("map veth pair %s to bridge %s", bridgeIfname, bridgeName)
-	cmd = exec.Command("sudo", "ip", "link", "set", bridgeIfname, "master", bridgeName)
-	err = runCmd(cmd)
+	nllA := &netlink.Veth{PeerName: bridgeIfname, LinkAttrs: netlink.LinkAttrs{Name: dummyIface, OperState: netlink.OperUp}}
+
+	err = netlink.LinkAdd(nllA)
 	if err != nil {
 		return err
 	}
-	log.Debugf("set interface '%s' state to up", bridgeIfname)
-	cmd = exec.Command("sudo", "ip", "link", "set", bridgeIfname, "up")
-	err = runCmd(cmd)
+
+	la := c.newLinkAttributes()
+	la.Name = containerIfName
+	la.Master = bridgeName
+	err = c.configVeth(dummyIface, la, containerNS)
 	if err != nil {
 		return err
 	}
+
 	log.Debugf("Disabling TX checksum offloading for the %s interface...", bridgeIfname)
 	err = EthtoolTXOff(bridgeIfname)
 	if err != nil {
@@ -169,17 +263,6 @@ func (c *cLab) DeleteNetnsSymlinks() (err error) {
 	return nil
 }
 
-func runCmd(cmd *exec.Cmd) error {
-	b, err := cmd.CombinedOutput()
-	if err != nil {
-		log.Debugf("'%s' failed with: %v", cmd.String(), err)
-		log.Debugf("'%s' failed output: %v", cmd.String(), string(b))
-		return err
-	}
-	log.Debugf("'%s' output: %v", cmd.String(), string(b))
-	return nil
-}
-
 func genIfName() string {
 	s, _ := uuid.New().MarshalText() // .MarshalText() always return a nil error
 	return string(s[:8])

go.mod

@@ -20,7 +20,7 @@ require (
 	github.com/spf13/cobra v1.0.0
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/vishvananda/netlink v1.1.0
-	github.com/vishvananda/netns v0.0.0-20200728191858-db3c7e526aae // indirect
+	github.com/vishvananda/netns v0.0.0-20200728191858-db3c7e526aae
 	golang.org/x/net v0.0.0-20200822124328-c89045814202 // indirect
 	gopkg.in/yaml.v2 v2.3.0
 )