network: Refactor network setup to avoid code duplication

Signed-off-by: Georgios Ntoutsos <[email protected]>
Reviewed-by: Charalampos Mainas <[email protected]>
Approved-by: Charalampos Mainas <[email protected]>
PR: #30

Author: Georgios Ntoutsos

cmd/urunc/create.go

@@ -80,7 +80,6 @@ var createCommand = cli.Command{
 			if err != nil {
 				return err
 			}
-
 			return createUnikontainer(context)
 		}
 		err := handleNonBimaContainer(context)

cmd/urunc/utils.go

@@ -87,6 +87,10 @@ func handleNonBimaContainer(context *cli.Context) error {
 		return nil
 	}
 	logrus.Info("This is a normal container. Calling runc...")
+	return runcExec()
+}
+
+func runcExec() error {
 	args := os.Args
 	binPath, err := exec.LookPath("runc")
 	if err != nil {
@@ -172,6 +176,7 @@ func handleQueueProxy(context *cli.Context) error {
 		if err != nil {
 			return fmt.Errorf("error writing to file: %v", err)
 		}
+		return runcExec()
 	}
 	return nil
 }

internal/constants/network_constants.go

@@ -17,6 +17,7 @@ package constants
 const (
 	StaticNetworkTapIP       = "172.16.1.1"
 	StaticNetworkUnikernelIP = "172.16.1.2"
-	DynamicNetworkTapIP      = "172.16.X.2"
-	QueueProxyRedirectIP     = "172.16.1.2"
+	// TODO: Experiment with DynamicNetworkTapIP starting from 172.16.X.1
+	DynamicNetworkTapIP  = "172.16.X.2"
+	QueueProxyRedirectIP = "172.16.1.2"
 )

internal/metrics/metrics.go

@@ -40,7 +40,6 @@ func NewZerologMetrics(target string) Writer {
 		if err != nil {
 			return nil
 		}
-		defer file.Close()
 		logger := zerolog.New(file).Level(zerolog.InfoLevel).With().Timestamp().Logger()
 		zerolog.TimeFieldFormat = zerolog.TimeFormatUnixNano
 		return &zerologMetrics{

pkg/network/network.go

@@ -18,6 +18,8 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"os/user"
+	"strconv"
 	"strings"
 
 	"github.com/jackpal/gateway"
@@ -72,6 +74,9 @@ func getTapIndex() (int, error) {
 			tapCount++
 		}
 	}
+	if tapCount > 255 {
+		return tapCount, fmt.Errorf("TAP interfaces count higher than 255")
+	}
 	return tapCount, nil
 }
 
@@ -212,3 +217,60 @@ func addRedirectFilter(source netlink.Link, target netlink.Link) error {
 		},
 	})
 }
+
+func networkSetup(tapName string, ipAdrress string, redirectLink netlink.Link, addTCRules bool) (netlink.Link, error) {
+	err := ensureEth0Exists()
+	// if eth0 does not exist in the namespace, the unikernel was spawned using ctr, so we skip the network setup
+	if err != nil {
+		netlog.Info("eth0 interface not found, assuming unikernel was spawned using ctr")
+		return nil, nil
+	}
+	currentUser, err := user.Current()
+	if err != nil {
+		return nil, err
+	}
+	uid, err := strconv.Atoi(currentUser.Uid)
+	if err != nil {
+		return nil, err
+	}
+	gid, err := strconv.Atoi(currentUser.Gid)
+	if err != nil {
+		return nil, err
+	}
+	newTapDevice, err := createTapDevice(tapName, redirectLink.Attrs().MTU, uid, gid)
+	if err != nil {
+		return nil, err
+	}
+	if addTCRules {
+		err = addIngressQdisc(newTapDevice)
+		if err != nil {
+			return nil, err
+		}
+		err = addIngressQdisc(redirectLink)
+		if err != nil {
+			return nil, err
+		}
+		err = addRedirectFilter(newTapDevice, redirectLink)
+		if err != nil {
+			return nil, err
+		}
+		err = addRedirectFilter(redirectLink, newTapDevice)
+		if err != nil {
+			return nil, err
+		}
+	}
+	ipn, err := netlink.ParseAddr(ipAdrress)
+	if err != nil {
+		return nil, err
+	}
+	err = netlink.AddrReplace(newTapDevice, ipn)
+	if err != nil {
+		return nil, err
+	}
+
+	err = netlink.LinkSetUp(newTapDevice)
+	if err != nil {
+		return nil, err
+	}
+	return newTapDevice, nil
+}

pkg/network/network_dynamic.go

@@ -16,7 +16,6 @@ package network
 
 import (
 	"fmt"
-	"os/user"
 	"strconv"
 	"strings"
 
@@ -37,72 +36,27 @@ type DynamicNetwork struct {
 // for multiple unikernels in the same pod/network namespace
 // See: https://github.com/nubificus/urunc/issues/13
 func (n DynamicNetwork) NetworkSetup() (*UnikernelNetworkInfo, error) {
-	err := ensureEth0Exists()
-	// if eth0 does not exist in the namespace, the unikernel was spawned using ctr, so we skip the network setup
-	if err != nil {
-		netlog.Info("eth0 interface not found, assuming unikernel was spawned using ctr")
-		return nil, nil
-	}
-	redirectLink, err := netlink.LinkByName(DefaultInterface)
-	if err != nil {
-		netlog.Errorf("failed to find %s  interface", DefaultInterface)
-		return nil, err
-	}
-	ifInfo, err := getInterfaceInfo(DefaultInterface)
-	if err != nil {
-		return nil, err
-	}
-	currentUser, err := user.Current()
-	if err != nil {
-		return nil, err
-	}
-	uid, err := strconv.Atoi(currentUser.Uid)
-	if err != nil {
-		return nil, err
-	}
-	gid, err := strconv.Atoi(currentUser.Gid)
-	if err != nil {
-		return nil, err
-	}
 	tapIndex, err := getTapIndex()
 	if err != nil {
 		return nil, err
 	}
-	newTapName := strings.ReplaceAll(DefaultTap, "X", strconv.Itoa(tapIndex))
-	newTapDevice, err := createTapDevice(newTapName, redirectLink.Attrs().MTU, uid, gid)
+	redirectLink, err := netlink.LinkByName(DefaultInterface)
 	if err != nil {
+		netlog.Errorf("failed to find %s interface", DefaultInterface)
 		return nil, err
 	}
+	newTapName := strings.ReplaceAll(DefaultTap, "X", strconv.Itoa(tapIndex))
+	addTCRules := false
 	if tapIndex == 0 {
-		err = addIngressQdisc(newTapDevice)
-		if err != nil {
-			return nil, err
-		}
-		err = addIngressQdisc(redirectLink)
-		if err != nil {
-			return nil, err
-		}
-		err = addRedirectFilter(newTapDevice, redirectLink)
-		if err != nil {
-			return nil, err
-		}
-		err = addRedirectFilter(redirectLink, newTapDevice)
-		if err != nil {
-			return nil, err
-		}
+		addTCRules = true
 	}
 	ipTemplate := fmt.Sprintf("%s/24", constants.DynamicNetworkTapIP)
 	newIPAddr := strings.ReplaceAll(ipTemplate, "X", strconv.Itoa(tapIndex+1))
-	ipn, err := netlink.ParseAddr(newIPAddr)
-	if err != nil {
-		return nil, err
-	}
-	err = netlink.AddrReplace(newTapDevice, ipn)
+	newTapDevice, err := networkSetup(newTapName, newIPAddr, redirectLink, addTCRules)
 	if err != nil {
 		return nil, err
 	}
-
-	err = netlink.LinkSetUp(newTapDevice)
+	ifInfo, err := getInterfaceInfo(DefaultInterface)
 	if err != nil {
 		return nil, err
 	}

pkg/network/network_static.go

@@ -16,8 +16,6 @@ package network
 
 import (
 	"fmt"
-	"os/user"
-	"strconv"
 	"strings"
 
 	"github.com/nubificus/urunc/internal/constants"
@@ -30,42 +28,14 @@ type StaticNetwork struct {
 }
 
 func (n StaticNetwork) NetworkSetup() (*UnikernelNetworkInfo, error) {
-	err := ensureEth0Exists()
-	if err != nil {
-		netlog.Error("failed to find eth0 interface in current netns")
-		return nil, err
-	}
-	redirectLink, err := netlink.LinkByName(DefaultInterface)
-	if err != nil {
-		netlog.Errorf("failed to find %s  interface", DefaultInterface)
-		return nil, err
-	}
-	currentUser, err := user.Current()
-	if err != nil {
-		return nil, err
-	}
-	uid, err := strconv.Atoi(currentUser.Uid)
-	if err != nil {
-		return nil, err
-	}
-	gid, err := strconv.Atoi(currentUser.Gid)
-	if err != nil {
-		return nil, err
-	}
 	newTapName := strings.ReplaceAll(DefaultTap, "X", "0")
-	newTapDevice, err := createTapDevice(newTapName, redirectLink.Attrs().MTU, uid, gid)
-	if err != nil {
-		return nil, err
-	}
-	ipn, err := netlink.ParseAddr(StaticIPAddr)
-	if err != nil {
-		return nil, err
-	}
-	err = netlink.AddrReplace(newTapDevice, ipn)
+	addTCRules := false
+	redirectLink, err := netlink.LinkByName(DefaultInterface)
 	if err != nil {
+		netlog.Errorf("failed to find %s interface", DefaultInterface)
 		return nil, err
 	}
-	err = netlink.LinkSetUp(newTapDevice)
+	newTapDevice, err := networkSetup(newTapName, StaticIPAddr, redirectLink, addTCRules)
 	if err != nil {
 		return nil, err
 	}
@@ -75,7 +45,7 @@ func (n StaticNetwork) NetworkSetup() (*UnikernelNetworkInfo, error) {
 			IP:             constants.StaticNetworkUnikernelIP,
 			DefaultGateway: constants.StaticNetworkTapIP,
 			Mask:           "255.255.255.0",
-			Interface:      "eth0", // or tap0_urunc?
+			Interface:      DefaultInterface, // or tap0_urunc?
 			MAC:            redirectLink.Attrs().HardwareAddr.String(),
 		},
 	}, nil

pkg/unikontainers/unikontainers.go

@@ -169,7 +169,7 @@ func (u *Unikontainer) Exec() error {
 	}
 	networkInfo, err := netManager.NetworkSetup()
 	if err != nil {
-		return err
+		Log.Errorf("Failed to setup network :%v. Possibly due to ctr", err)
 	}
 	metrics.Capture(u.State.ID, "TS17")