Refactor TUN setup (isolated config)

cmd/yggdrasil/main.go

@@ -38,7 +38,6 @@ import (
 
 type node struct {
 	core      *core.Core
-	config    *config.NodeConfig
 	tuntap    *tuntap.TunAdapter
 	multicast *multicast.Multicast
 	admin     *admin.AdminSocket
@@ -326,7 +325,7 @@ func run(args yggArgs, ctx context.Context, done chan struct{}) {
 	default:
 	}
 
-	n := &node{config: cfg}
+	n := &node{}
 
 	// Setup the Yggdrasil node itself.
 	{
@@ -390,15 +389,22 @@ func run(args yggArgs, ctx context.Context, done chan struct{}) {
 		}
 	}
 
-	// Start the TUN/TAP interface
-	n.tuntap = &tuntap.TunAdapter{}
-	rwc := ipv6rwc.NewReadWriteCloser(n.core)
-	if err := n.tuntap.Init(rwc, cfg, logger, nil); err != nil {
-		logger.Errorln("An error occurred initialising TUN/TAP:", err)
-	} else if err := n.tuntap.Start(); err != nil {
-		logger.Errorln("An error occurred starting TUN/TAP:", err)
+	// Setup the TUN module.
+	{
+		options := []tuntap.SetupOption{
+			tuntap.InterfaceName(cfg.IfName),
+			tuntap.InterfaceMTU(cfg.IfMTU),
 		}
+		rwc := ipv6rwc.NewReadWriteCloser(n.core)
+		n.tuntap, err = tuntap.New(rwc, logger, options...)
+		if err != nil {
+			panic(err)
+		}
+		if n.admin != nil {
 			n.tuntap.SetupAdminHandlers(n.admin)
+		}
+	}
+
 	// Make some nice output that tells us what our IPv6 address and subnet are.
 	// This is just logged to stdout for the user.
 	address := n.core.Address()

src/multicast/multicast.go

@@ -80,8 +80,8 @@ func (m *Multicast) _start() error {
 	if len(m.config._interfaces) == 0 {
 		return nil
 	}
-	m.log.Infoln("Starting multicast module")
-	defer m.log.Infoln("Started multicast module")
+	m.log.Debugln("Starting multicast module")
+	defer m.log.Debugln("Started multicast module")
 	addr, err := net.ResolveUDPAddr("udp", string(m.config._groupAddr))
 	if err != nil {
 		return err

src/tuntap/options.go

@@ -0,0 +1,20 @@
+package tuntap
+
+func (m *TunAdapter) _applyOption(opt SetupOption) {
+	switch v := opt.(type) {
+	case InterfaceName:
+		m.config.name = v
+	case InterfaceMTU:
+		m.config.mtu = v
+	}
+}
+
+type SetupOption interface {
+	isSetupOption()
+}
+
+type InterfaceName string
+type InterfaceMTU uint64
+
+func (a InterfaceName) isSetupOption() {}
+func (a InterfaceMTU) isSetupOption()  {}

src/tuntap/tun.go

@@ -16,13 +16,12 @@ import (
 	//"sync"
 
 	"github.com/Arceliar/phony"
-	"github.com/gologme/log"
 	"golang.zx2c4.com/wireguard/tun"
 
 	"github.com/yggdrasil-network/yggdrasil-go/src/address"
-	"github.com/yggdrasil-network/yggdrasil-go/src/config"
 	"github.com/yggdrasil-network/yggdrasil-go/src/defaults"
 	"github.com/yggdrasil-network/yggdrasil-go/src/ipv6rwc"
+	"github.com/yggdrasil-network/yggdrasil-go/src/util"
 )
 
 type MTU uint16
@@ -33,8 +32,7 @@ type MTU uint16
 // calling yggdrasil.Start().
 type TunAdapter struct {
 	rwc         *ipv6rwc.ReadWriteCloser
-	config      *config.NodeConfig
-	log         *log.Logger
+	log         util.Logger
 	addr        address.Address
 	subnet      address.Subnet
 	mtu         uint64
@@ -43,6 +41,10 @@ type TunAdapter struct {
 	//mutex        sync.RWMutex // Protects the below
 	isOpen    bool
 	isEnabled bool // Used by the writer to drop sessionTraffic if not enabled
+	config    struct {
+		name InterfaceName
+		mtu  InterfaceMTU
+	}
 }
 
 // Gets the maximum supported MTU for the platform based on the defaults in
@@ -93,50 +95,39 @@ func MaximumMTU() uint64 {
 
 // Init initialises the TUN module. You must have acquired a Listener from
 // the Yggdrasil core before this point and it must not be in use elsewhere.
-func (tun *TunAdapter) Init(rwc *ipv6rwc.ReadWriteCloser, config *config.NodeConfig, log *log.Logger, options interface{}) error {
-	tun.rwc = rwc
-	tun.config = config
-	tun.log = log
-	return nil
+func New(rwc *ipv6rwc.ReadWriteCloser, log util.Logger, opts ...SetupOption) (*TunAdapter, error) {
+	tun := &TunAdapter{
+		rwc: rwc,
+		log: log,
 	}
-
-// Start the setup process for the TUN adapter. If successful, starts the
-// reader actor to handle packets on that interface.
-func (tun *TunAdapter) Start() error {
-	var err error
-	phony.Block(tun, func() {
-		err = tun._start()
-	})
-	return err
+	for _, opt := range opts {
+		tun._applyOption(opt)
+	}
+	return tun, tun._start()
 }
 
 func (tun *TunAdapter) _start() error {
 	if tun.isOpen {
 		return errors.New("TUN module is already started")
 	}
-	if tun.config == nil {
-		return errors.New("no configuration available to TUN")
-	}
-	tun.config.RLock()
-	defer tun.config.RUnlock()
 	tun.addr = tun.rwc.Address()
 	tun.subnet = tun.rwc.Subnet()
 	addr := fmt.Sprintf("%s/%d", net.IP(tun.addr[:]).String(), 8*len(address.GetPrefix())-1)
-	if tun.config.IfName == "none" || tun.config.IfName == "dummy" {
+	if tun.config.name == "none" || tun.config.name == "dummy" {
 		tun.log.Debugln("Not starting TUN as ifname is none or dummy")
 		tun.isEnabled = false
 		go tun.write()
 		return nil
 	}
-	mtu := tun.config.IfMTU
+	mtu := uint64(tun.config.mtu)
 	if tun.rwc.MaxMTU() < mtu {
 		mtu = tun.rwc.MaxMTU()
 	}
-	if err := tun.setup(tun.config.IfName, addr, mtu); err != nil {
+	if err := tun.setup(string(tun.config.name), addr, mtu); err != nil {
 		return err
 	}
 	if tun.MTU() != mtu {
-		tun.log.Warnf("Warning: Interface MTU %d automatically adjusted to %d (supported range is 1280-%d)", tun.config.IfMTU, tun.MTU(), MaximumMTU())
+		tun.log.Warnf("Warning: Interface MTU %d automatically adjusted to %d (supported range is 1280-%d)", tun.config.mtu, tun.MTU(), MaximumMTU())
 	}
 	tun.rwc.SetMTU(tun.MTU())
 	tun.isOpen = true