Hashing the WireGuard interface

Hashing the interface and using ephmeral ports so that the admin doesn't
choose an interface and port combination. An administrator can alteranatively
decide to provide port but this isn't critical.

cmd/wg-mesh/main.go

@@ -16,7 +16,6 @@ const SockAddr = "/tmp/wgmesh_ipc.sock"
 
 type CreateMeshParams struct {
 	Client   *ipcRpc.Client
-	IfName   string
 	WgPort   int
 	Endpoint string
 }
@@ -24,7 +23,6 @@ type CreateMeshParams struct {
 func createMesh(args *CreateMeshParams) string {
 	var reply string
 	newMeshParams := ipc.NewMeshArgs{
-		IfName:   args.IfName,
 		WgPort:   args.WgPort,
 		Endpoint: args.Endpoint,
 	}
@@ -68,7 +66,6 @@ func joinMesh(params *JoinMeshParams) string {
 	args := ipc.JoinMeshArgs{
 		MeshId:   params.MeshId,
 		IpAdress: params.IpAddress,
-		IfName:   params.IfName,
 		Port:     params.WgPort,
 	}
 
@@ -251,14 +248,12 @@ func main() {
 	deleteServiceCmd := parser.NewCommand("delete-service", "Remove a service from your advertisements")
 	getNodeCmd := parser.NewCommand("get-node", "Get a specific node from the mesh")
 
-	var newMeshIfName *string = newMeshCmd.String("f", "ifname", &argparse.Options{Required: true})
-	var newMeshPort *int = newMeshCmd.Int("p", "wgport", &argparse.Options{Required: true})
+	var newMeshPort *int = newMeshCmd.Int("p", "wgport", &argparse.Options{})
 	var newMeshEndpoint *string = newMeshCmd.String("e", "endpoint", &argparse.Options{})
 
 	var joinMeshId *string = joinMeshCmd.String("m", "mesh", &argparse.Options{Required: true})
 	var joinMeshIpAddress *string = joinMeshCmd.String("i", "ip", &argparse.Options{Required: true})
-	var joinMeshIfName *string = joinMeshCmd.String("f", "ifname", &argparse.Options{Required: true})
-	var joinMeshPort *int = joinMeshCmd.Int("p", "wgport", &argparse.Options{Required: true})
+	var joinMeshPort *int = joinMeshCmd.Int("p", "wgport", &argparse.Options{})
 	var joinMeshEndpoint *string = joinMeshCmd.String("e", "endpoint", &argparse.Options{})
 
 	var enableInterfaceMeshId *string = enableInterfaceCmd.String("m", "mesh", &argparse.Options{Required: true})
@@ -298,7 +293,6 @@ func main() {
 	if newMeshCmd.Happened() {
 		fmt.Println(createMesh(&CreateMeshParams{
 			Client:   client,
-			IfName:   *newMeshIfName,
 			WgPort:   *newMeshPort,
 			Endpoint: *newMeshEndpoint,
 		}))
@@ -311,7 +305,6 @@ func main() {
 	if joinMeshCmd.Happened() {
 		fmt.Println(joinMesh(&JoinMeshParams{
 			Client:    client,
-			IfName:    *joinMeshIfName,
 			WgPort:    *joinMeshPort,
 			IpAddress: *joinMeshIpAddress,
 			MeshId:    *joinMeshId,

pkg/api/apiserver.go

@@ -62,11 +62,11 @@ func (s *SmegServer) CreateMesh(c *gin.Context) {
 		c.JSON(http.StatusBadRequest, &gin.H{
 			"error": err.Error(),
 		})
+
 		return
 	}
 
 	ipcRequest := ipc.NewMeshArgs{
-		IfName: createMesh.IfName,
 		WgPort: createMesh.WgPort,
 	}
 
@@ -100,7 +100,6 @@ func (s *SmegServer) JoinMesh(c *gin.Context) {
 	ipcRequest := ipc.JoinMeshArgs{
 		MeshId:   joinMesh.MeshId,
 		IpAdress: joinMesh.Bootstrap,
-		IfName:   joinMesh.IfName,
 		Port:     joinMesh.WgPort,
 	}
 

pkg/api/types.go

@@ -18,13 +18,11 @@ type SmegMesh struct {
 }
 
 type CreateMeshRequest struct {
-	IfName string `json:"ifName" binding:"required"`
-	WgPort int    `json:"port" binding:"required,gte=1024,lt=65535"`
+	WgPort int `json:"port" binding:"gte=1024,lt=65535"`
 }
 
 type JoinMeshRequest struct {
-	IfName    string `json:"ifName" binding:"required"`
-	WgPort    int    `json:"port" binding:"required,gte=1024,lt=65535"`
+	WgPort    int    `json:"port" binding:"gte=1024,lt=65535"`
 	Bootstrap string `json:"bootstrap" binding:"required"`
 	MeshId    string `json:"meshid" binding:"required"`
 }

pkg/ipc/ipc.go

@@ -11,8 +11,6 @@ import (
 )
 
 type NewMeshArgs struct {
-	// IfName is the interface that the mesh instance will run on
-	IfName string
 	// WgPort is the WireGuard port to expose
 	WgPort int
 	// Endpoint is the routable alias of the machine. Can be an IP
@@ -25,8 +23,6 @@ type JoinMeshArgs struct {
 	MeshId string
 	// IpAddress is a routable IP in another mesh
 	IpAdress string
-	// IfName is the interface name of the mesh
-	IfName string
 	// Port is the WireGuard port to expose
 	Port int
 	// Endpoint is the routable address of this machine. If not provided

pkg/mesh/manager.go

@@ -14,7 +14,7 @@ import (
 )
 
 type MeshManager interface {
-	CreateMesh(devName string, port int) (string, error)
+	CreateMesh(port int) (string, error)
 	AddMesh(params *AddMeshParams) error
 	HasChanges(meshid string) bool
 	GetMesh(meshId string) MeshProvider
@@ -115,15 +115,25 @@ func (m *MeshManagerImpl) Prune() error {
 }
 
 // CreateMesh: Creates a new mesh, stores it and returns the mesh id
-func (m *MeshManagerImpl) CreateMesh(devName string, port int) (string, error) {
+func (m *MeshManagerImpl) CreateMesh(port int) (string, error) {
 	meshId, err := m.idGenerator.GetId()
 
+	var ifName string = ""
+
 	if err != nil {
 		return "", err
 	}
 
+	if !m.conf.StubWg {
+		ifName, err = m.interfaceManipulator.CreateInterface(port)
+
+		if err != nil {
+			return "", fmt.Errorf("error creating mesh: %w", err)
+		}
+	}
+
 	nodeManager, err := m.meshProviderFactory.CreateMesh(&MeshProviderFactoryParams{
-		DevName: devName,
+		DevName: ifName,
 		Port:    port,
 		Conf:    m.conf,
 		Client:  m.Client,
@@ -134,32 +144,31 @@ func (m *MeshManagerImpl) CreateMesh(devName string, port int) (string, error) {
 		return "", fmt.Errorf("error creating mesh: %w", err)
 	}
 
-	if !m.conf.StubWg {
-		err = m.interfaceManipulator.CreateInterface(&wg.CreateInterfaceParams{
-			IfName: devName,
-			Port:   port,
-		})
-
-		if err != nil {
-			return "", fmt.Errorf("error creating mesh: %w", err)
-		}
-	}
-
 	m.Meshes[meshId] = nodeManager
 	return meshId, nil
 }
 
 type AddMeshParams struct {
 	MeshId    string
-	DevName   string
 	WgPort    int
 	MeshBytes []byte
 }
 
 // AddMesh: Add the mesh to the list of meshes
 func (m *MeshManagerImpl) AddMesh(params *AddMeshParams) error {
+	var ifName string
+	var err error
+
+	if !m.conf.StubWg {
+		ifName, err = m.interfaceManipulator.CreateInterface(params.WgPort)
+
+		if err != nil {
+			return err
+		}
+	}
+
 	meshProvider, err := m.meshProviderFactory.CreateMesh(&MeshProviderFactoryParams{
-		DevName: params.DevName,
+		DevName: ifName,
 		Port:    params.WgPort,
 		Conf:    m.conf,
 		Client:  m.Client,
@@ -177,14 +186,6 @@ func (m *MeshManagerImpl) AddMesh(params *AddMeshParams) error {
 	}
 
 	m.Meshes[params.MeshId] = meshProvider
-
-	if !m.conf.StubWg {
-		return m.interfaceManipulator.CreateInterface(&wg.CreateInterfaceParams{
-			IfName: params.DevName,
-			Port:   params.WgPort,
-		})
-	}
-
 	return nil
 }
 

pkg/mesh/stub_types.go

@@ -250,7 +250,7 @@ func NewMeshManagerStub() MeshManager {
 	return &MeshManagerStub{meshes: make(map[string]MeshProvider)}
 }
 
-func (m *MeshManagerStub) CreateMesh(devName string, port int) (string, error) {
+func (m *MeshManagerStub) CreateMesh(port int) (string, error) {
 	return "tim123", nil
 }
 

pkg/robin/requester.go

@@ -20,7 +20,7 @@ type IpcHandler struct {
 }
 
 func (n *IpcHandler) CreateMesh(args *ipc.NewMeshArgs, reply *string) error {
-	meshId, err := n.Server.GetMeshManager().CreateMesh(args.IfName, args.WgPort)
+	meshId, err := n.Server.GetMeshManager().CreateMesh(args.WgPort)
 
 	if err != nil {
 		return err
@@ -83,7 +83,6 @@ func (n *IpcHandler) JoinMesh(args ipc.JoinMeshArgs, reply *string) error {
 
 	err = n.Server.GetMeshManager().AddMesh(&mesh.AddMeshParams{
 		MeshId:    args.MeshId,
-		DevName:   args.IfName,
 		WgPort:    args.Port,
 		MeshBytes: meshReply.Mesh,
 	})

pkg/sync/syncrequester.go

@@ -50,7 +50,6 @@ func (s *SyncRequesterImpl) GetMesh(meshId string, ifName string, port int, endP
 
 	err = s.server.MeshManager.AddMesh(&mesh.AddMeshParams{
 		MeshId:    meshId,
-		DevName:   ifName,
 		WgPort:    port,
 		MeshBytes: reply.Mesh,
 	})

pkg/wg/stubs.go

@@ -2,7 +2,7 @@ package wg
 
 type WgInterfaceManipulatorStub struct{}
 
-func (i *WgInterfaceManipulatorStub) CreateInterface(params *CreateInterfaceParams) error {
+func (i *WgInterfaceManipulatorStub) CreateInterface(port int) error {
 	return nil
 }
 

pkg/wg/types.go

@@ -8,14 +8,9 @@ func (m *WgError) Error() string {
 	return m.msg
 }
 
-type CreateInterfaceParams struct {
-	IfName string
-	Port   int
-}
-
 type WgInterfaceManipulator interface {
 	// CreateInterface creates a WireGuard interface
-	CreateInterface(params *CreateInterfaceParams) error
+	CreateInterface(port int) (string, error)
 	// AddAddress adds an address to the given interface name
 	AddAddress(ifName string, addr string) error
 	// RemoveInterface removes the specified interface

pkg/wg/wg.go

@@ -1,6 +1,9 @@
 package wg
 
 import (
+	"crypto"
+	"crypto/rand"
+	"encoding/base64"
 	"fmt"
 
 	"github.com/tim-beatham/wgmesh/pkg/lib"
@@ -13,40 +16,54 @@ type WgInterfaceManipulatorImpl struct {
 	client *wgctrl.Client
 }
 
+const hashLength = 6
+
 // CreateInterface creates a WireGuard interface
-func (m *WgInterfaceManipulatorImpl) CreateInterface(params *CreateInterfaceParams) error {
+func (m *WgInterfaceManipulatorImpl) CreateInterface(port int) (string, error) {
 	rtnl, err := lib.NewRtNetlinkConfig()
 
 	if err != nil {
-		return fmt.Errorf("failed to access link: %w", err)
+		return "", fmt.Errorf("failed to access link: %w", err)
 	}
 	defer rtnl.Close()
 
-	err = rtnl.CreateLink(params.IfName)
+	randomBuf := make([]byte, 32)
+	_, err = rand.Read(randomBuf)
 
 	if err != nil {
-		return fmt.Errorf("failed to create link: %w", err)
+		return "", err
+	}
+
+	md5 := crypto.MD5.New().Sum(randomBuf)
+
+	md5Str := fmt.Sprintf("wg%s", base64.StdEncoding.EncodeToString(md5)[:hashLength])
+
+	err = rtnl.CreateLink(md5Str)
+
+	if err != nil {
+		return "", fmt.Errorf("failed to create link: %w", err)
 	}
 
 	privateKey, err := wgtypes.GeneratePrivateKey()
 
 	if err != nil {
-		return fmt.Errorf("failed to create private key: %w", err)
+		return "", fmt.Errorf("failed to create private key: %w", err)
 	}
 
 	var cfg wgtypes.Config = wgtypes.Config{
 		PrivateKey: &privateKey,
-		ListenPort: &params.Port,
+		ListenPort: &port,
 	}
 
-	err = m.client.ConfigureDevice(params.IfName, cfg)
+	err = m.client.ConfigureDevice(md5Str, cfg)
 
 	if err != nil {
-		return fmt.Errorf("failed to configure dev: %w", err)
+		m.RemoveInterface(md5Str)
+		return "", fmt.Errorf("failed to configure dev: %w", err)
 	}
 
-	logging.Log.WriteInfof("ip link set up dev %s type wireguard", params.IfName)
-	return nil
+	logging.Log.WriteInfof("ip link set up dev %s type wireguard", md5Str)
+	return md5Str, nil
 }
 
 // Add an address to the given interface