Handle peer interface config change (#348)

Before this change, NetBird Agent wasn't handling
peer interface configuration changes dynamically.
Also, remote peer configuration changes have
not been applied (e.g. AllowedIPs changed).
Not a very common cause, but still it should be handled.
Now, Agent reacts to PeerConfig changes sent from the
management service and restarts remote connections
if AllowedIps have been changed.

iface/configuration.go

@@ -30,6 +30,8 @@ func (w *WGIface) configureDevice(config wgtypes.Config) error {
 // Configure configures a Wireguard interface
 // The interface must exist before calling this method (e.g. call interface.Create() before)
 func (w *WGIface) Configure(privateKey string, port int) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
 
 	log.Debugf("configuring Wireguard interface %s", w.Name)
 
@@ -76,6 +78,8 @@ func (w *WGIface) GetListenPort() (*int, error) {
 // UpdatePeer updates existing Wireguard Peer or creates a new one if doesn't exist
 // Endpoint is optional
 func (w *WGIface) UpdatePeer(peerKey string, allowedIps string, keepAlive time.Duration, endpoint *net.UDPAddr, preSharedKey *wgtypes.Key) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
 
 	log.Debugf("updating interface %s peer %s: endpoint %s ", w.Name, peerKey, endpoint)
 
@@ -110,6 +114,9 @@ func (w *WGIface) UpdatePeer(peerKey string, allowedIps string, keepAlive time.D
 
 // RemovePeer removes a Wireguard Peer from the interface iface
 func (w *WGIface) RemovePeer(peerKey string) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
 	log.Debugf("Removing peer %s from interface %s ", peerKey, w.Name)
 
 	peerKeyParsed, err := wgtypes.ParseKey(peerKey)

iface/iface.go

@@ -1,10 +1,11 @@
 package iface
 
 import (
-	"golang.zx2c4.com/wireguard/wgctrl"
+	"fmt"
 	"net"
 	"os"
 	"runtime"
+	"sync"
 )
 
 const (
@@ -19,6 +20,7 @@ type WGIface struct {
 	MTU       int
 	Address   WGAddress
 	Interface NetInterface
+	mu        sync.Mutex
 }
 
 // WGAddress Wireguard parsed address
@@ -27,16 +29,22 @@ type WGAddress struct {
 	Network *net.IPNet
 }
 
+func (addr *WGAddress) String() string {
+	maskSize, _ := addr.Network.Mask.Size()
+	return fmt.Sprintf("%s/%d", addr.IP.String(), maskSize)
+}
+
 // NetInterface represents a generic network tunnel interface
 type NetInterface interface {
 	Close() error
 }
 
-// NewWGIface Creates a new Wireguard interface instance
-func NewWGIface(iface string, address string, mtu int) (WGIface, error) {
-	wgIface := WGIface{
+// NewWGIFace Creates a new Wireguard interface instance
+func NewWGIFace(iface string, address string, mtu int) (*WGIface, error) {
+	wgIface := &WGIface{
 		Name: iface,
 		MTU:  mtu,
+		mu:   sync.Mutex{},
 	}
 
 	wgAddress, err := parseAddress(address)
@@ -49,30 +57,6 @@ func NewWGIface(iface string, address string, mtu int) (WGIface, error) {
 	return wgIface, nil
 }
 
-// Exists checks whether specified Wireguard device exists or not
-func Exists(iface string) (*bool, error) {
-	wg, err := wgctrl.New()
-	if err != nil {
-		return nil, err
-	}
-	defer wg.Close()
-
-	devices, err := wg.Devices()
-	if err != nil {
-		return nil, err
-	}
-
-	var exists bool
-	for _, d := range devices {
-		if d.Name == iface {
-			exists = true
-			return &exists, nil
-		}
-	}
-	exists = false
-	return &exists, nil
-}
-
 // parseAddress parse a string ("1.2.3.4/24") address to WG Address
 func parseAddress(address string) (WGAddress, error) {
 	ip, network, err := net.ParseCIDR(address)
@@ -85,8 +69,10 @@ func parseAddress(address string) (WGAddress, error) {
 	}, nil
 }
 
-// Closes the tunnel interface
+// Close closes the tunnel interface
 func (w *WGIface) Close() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
 
 	err := w.Interface.Close()
 	if err != nil {

iface/iface_darwin.go

@@ -7,7 +7,10 @@ import (
 
 // Create Creates a new Wireguard interface, sets a given IP and brings it up.
 func (w *WGIface) Create() error {
-	return w.CreateWithUserspace()
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	return w.createWithUserspace()
 }
 
 // assignAddr Adds IP address to the tunnel interface and network route based on the range provided

iface/iface_linux.go

@@ -2,7 +2,6 @@ package iface
 
 import (
 	"errors"
-	"fmt"
 	"math"
 	"os"
 	"syscall"
@@ -33,22 +32,24 @@ func WireguardModExists() bool {
 	return errors.Is(err, syscall.EINVAL)
 }
 
-// Create Creates a new Wireguard interface, sets a given IP and brings it up.
+// Create creates a new Wireguard interface, sets a given IP and brings it up.
 // Will reuse an existing one.
 func (w *WGIface) Create() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
 
 	if WireguardModExists() {
 		log.Info("using kernel WireGuard")
-		return w.CreateWithKernel()
+		return w.createWithKernel()
 	} else {
 		log.Info("using userspace WireGuard")
-		return w.CreateWithUserspace()
+		return w.createWithUserspace()
 	}
 }
 
-// CreateWithKernel Creates a new Wireguard interface using kernel Wireguard module.
+// createWithKernel Creates a new Wireguard interface using kernel Wireguard module.
 // Works for Linux and offers much better network performance
-func (w *WGIface) CreateWithKernel() error {
+func (w *WGIface) createWithKernel() error {
 
 	link := newWGLink(w.Name)
 
@@ -106,10 +107,6 @@ func (w *WGIface) CreateWithKernel() error {
 
 // assignAddr Adds IP address to the tunnel interface
 func (w *WGIface) assignAddr() error {
-
-	mask, _ := w.Address.Network.Mask.Size()
-	address := fmt.Sprintf("%s/%d", w.Address.IP.String(), mask)
-
 	link := newWGLink(w.Name)
 
 	//delete existing addresses
@@ -126,11 +123,11 @@ func (w *WGIface) assignAddr() error {
 		}
 	}
 
-	log.Debugf("adding address %s to interface: %s", address, w.Name)
-	addr, _ := netlink.ParseAddr(address)
+	log.Debugf("adding address %s to interface: %s", w.Address.String(), w.Name)
+	addr, _ := netlink.ParseAddr(w.Address.String())
 	err = netlink.AddrAdd(link, addr)
 	if os.IsExist(err) {
-		log.Infof("interface %s already has the address: %s", w.Name, address)
+		log.Infof("interface %s already has the address: %s", w.Name, w.Address.String())
 	} else if err != nil {
 		return err
 	}

iface/iface_test.go

@@ -3,6 +3,7 @@ package iface
 import (
 	"fmt"
 	log "github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
 	"golang.zx2c4.com/wireguard/wgctrl"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 	"net"
@@ -28,11 +29,71 @@ func init() {
 	peerPubKey = peerPrivateKey.PublicKey().String()
 }
 
+func TestWGIface_UpdateAddr(t *testing.T) {
+	ifaceName := fmt.Sprintf("utun%d", WgIntNumber+4)
+	addr := "100.64.0.1/8"
+	iface, err := NewWGIFace(ifaceName, addr, DefaultMTU)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = iface.Create()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		err = iface.Close()
+		if err != nil {
+			t.Error(err)
+		}
+	}()
+	port, err := iface.GetListenPort()
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = iface.Configure(key, *port)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	addrs, err := getIfaceAddrs(ifaceName)
+	if err != nil {
+		t.Error(err)
+	}
+	assert.Equal(t, addr, addrs[0].String())
+
+	//update WireGuard address
+	addr = "100.64.0.2/8"
+	err = iface.UpdateAddr(addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	addrs, err = getIfaceAddrs(ifaceName)
+	if err != nil {
+		t.Error(err)
+	}
+
+	assert.Equal(t, addr, addrs[0].String())
+
+}
+
+func getIfaceAddrs(ifaceName string) ([]net.Addr, error) {
+	ief, err := net.InterfaceByName(ifaceName)
+	if err != nil {
+		return nil, err
+	}
+	addrs, err := ief.Addrs()
+	if err != nil {
+		return nil, err
+	}
+	return addrs, nil
+}
+
 //
 func Test_CreateInterface(t *testing.T) {
 	ifaceName := fmt.Sprintf("utun%d", WgIntNumber+1)
 	wgIP := "10.99.99.1/32"
-	iface, err := NewWGIface(ifaceName, wgIP, DefaultMTU)
+	iface, err := NewWGIFace(ifaceName, wgIP, DefaultMTU)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -61,7 +122,7 @@ func Test_CreateInterface(t *testing.T) {
 func Test_Close(t *testing.T) {
 	ifaceName := fmt.Sprintf("utun%d", WgIntNumber+2)
 	wgIP := "10.99.99.2/32"
-	iface, err := NewWGIface(ifaceName, wgIP, DefaultMTU)
+	iface, err := NewWGIFace(ifaceName, wgIP, DefaultMTU)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -89,7 +150,7 @@ func Test_Close(t *testing.T) {
 func Test_ConfigureInterface(t *testing.T) {
 	ifaceName := fmt.Sprintf("utun%d", WgIntNumber+3)
 	wgIP := "10.99.99.5/30"
-	iface, err := NewWGIface(ifaceName, wgIP, DefaultMTU)
+	iface, err := NewWGIFace(ifaceName, wgIP, DefaultMTU)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -136,7 +197,7 @@ func Test_ConfigureInterface(t *testing.T) {
 func Test_UpdatePeer(t *testing.T) {
 	ifaceName := fmt.Sprintf("utun%d", WgIntNumber+4)
 	wgIP := "10.99.99.9/30"
-	iface, err := NewWGIface(ifaceName, wgIP, DefaultMTU)
+	iface, err := NewWGIFace(ifaceName, wgIP, DefaultMTU)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -195,7 +256,7 @@ func Test_UpdatePeer(t *testing.T) {
 func Test_RemovePeer(t *testing.T) {
 	ifaceName := fmt.Sprintf("utun%d", WgIntNumber+4)
 	wgIP := "10.99.99.13/30"
-	iface, err := NewWGIface(ifaceName, wgIP, DefaultMTU)
+	iface, err := NewWGIFace(ifaceName, wgIP, DefaultMTU)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -247,7 +308,7 @@ func Test_ConnectPeers(t *testing.T) {
 
 	keepAlive := 1 * time.Second
 
-	iface1, err := NewWGIface(peer1ifaceName, peer1wgIP, DefaultMTU)
+	iface1, err := NewWGIFace(peer1ifaceName, peer1wgIP, DefaultMTU)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -264,7 +325,7 @@ func Test_ConnectPeers(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	iface2, err := NewWGIface(peer2ifaceName, peer2wgIP, DefaultMTU)
+	iface2, err := NewWGIFace(peer2ifaceName, peer2wgIP, DefaultMTU)
 	if err != nil {
 		t.Fatal(err)
 	}

iface/iface_unix.go

@@ -12,8 +12,8 @@ import (
 	"net"
 )
 
-// CreateWithUserspace Creates a new Wireguard interface, using wireguard-go userspace implementation
-func (w *WGIface) CreateWithUserspace() error {
+// createWithUserspace Creates a new Wireguard interface, using wireguard-go userspace implementation
+func (w *WGIface) createWithUserspace() error {
 
 	tunIface, err := tun.CreateTUN(w.Name, w.MTU)
 	if err != nil {
@@ -61,3 +61,17 @@ func getUAPI(iface string) (net.Listener, error) {
 	}
 	return ipc.UAPIListen(iface, tunSock)
 }
+
+// UpdateAddr updates address of the interface
+func (w *WGIface) UpdateAddr(newAddr string) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	addr, err := parseAddress(newAddr)
+	if err != nil {
+		return err
+	}
+
+	w.Address = addr
+	return w.assignAddr()
+}

iface/iface_windows.go

@@ -11,6 +11,8 @@ import (
 
 // Create Creates a new Wireguard interface, sets a given IP and brings it up.
 func (w *WGIface) Create() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
 
 	WintunStaticRequestedGUID, _ := windows.GenerateGUID()
 	adapter, err := driver.CreateAdapter(w.Name, "WireGuard", &WintunStaticRequestedGUID)
@@ -40,3 +42,18 @@ func (w *WGIface) assignAddr(luid winipcfg.LUID) error {
 
 	return nil
 }
+
+// UpdateAddr updates address of the interface
+func (w *WGIface) UpdateAddr(newAddr string) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	luid := w.Interface.(*driver.Adapter).LUID()
+	addr, err := parseAddress(newAddr)
+	if err != nil {
+		return err
+	}
+
+	w.Address = addr
+	return w.assignAddr(luid)
+}