Enable IPv6 address discovery (#578)

Agents will use IPv6 when available for ICE negotiation

client/internal/config.go

@@ -40,6 +40,7 @@ type Config struct {
 	WgIface              string
 	WgPort               int
 	IFaceBlackList       []string
+	DisableIPv6Discovery bool
 	// SSHKey is a private SSH key in a PEM format
 	SSHKey         string
 
@@ -74,6 +75,7 @@ func createNewConfig(managementURL, adminURL, configPath, preSharedKey string) (
 		WgIface:              iface.WgInterfaceDefault,
 		WgPort:               iface.DefaultWgPort,
 		IFaceBlackList:       []string{},
+		DisableIPv6Discovery: false,
 	}
 	if managementURL != "" {
 		URL, err := ParseURL("Management URL", managementURL)

client/internal/connect.go

@@ -188,6 +188,7 @@ func createEngineConfig(key wgtypes.Key, config *Config, peerConfig *mgmProto.Pe
 		WgIfaceName:          config.WgIface,
 		WgAddr:               peerConfig.Address,
 		IFaceBlackList:       config.IFaceBlackList,
+		DisableIPv6Discovery: config.DisableIPv6Discovery,
 		WgPrivateKey:         key,
 		WgPort:               config.WgPort,
 		SSHKey:               []byte(config.SSHKey),

client/internal/engine.go

@@ -56,6 +56,7 @@ type EngineConfig struct {
 
 	// IFaceBlackList is a list of network interfaces to ignore when discovering connection candidates (ICE related)
 	IFaceBlackList       []string
+	DisableIPv6Discovery bool
 
 	PreSharedKey *wgtypes.Key
 
@@ -226,13 +227,18 @@ func (e *Engine) Start() error {
 		return err
 	}
 
-	e.udpMuxConn, err = net.ListenUDP("udp4", &net.UDPAddr{Port: e.config.UDPMuxPort})
+	networkName := "udp"
+	if e.config.DisableIPv6Discovery {
+		networkName = "udp4"
+	}
+
+	e.udpMuxConn, err = net.ListenUDP(networkName, &net.UDPAddr{Port: e.config.UDPMuxPort})
 	if err != nil {
 		log.Errorf("failed listening on UDP port %d: [%s]", e.config.UDPMuxPort, err.Error())
 		return err
 	}
 
-	e.udpMuxConnSrflx, err = net.ListenUDP("udp4", &net.UDPAddr{Port: e.config.UDPMuxSrflxPort})
+	e.udpMuxConnSrflx, err = net.ListenUDP(networkName, &net.UDPAddr{Port: e.config.UDPMuxSrflxPort})
 	if err != nil {
 		log.Errorf("failed listening on UDP port %d: [%s]", e.config.UDPMuxSrflxPort, err.Error())
 		return err
@@ -823,6 +829,7 @@ func (e Engine) createPeerConn(pubKey string, allowedIPs string) (*peer.Conn, er
 		LocalKey:             e.config.WgPrivateKey.PublicKey().String(),
 		StunTurn:             stunTurn,
 		InterfaceBlackList:   e.config.IFaceBlackList,
+		DisableIPv6Discovery: e.config.DisableIPv6Discovery,
 		Timeout:              timeout,
 		UDPMux:               e.udpMux,
 		UDPMuxSrflx:          e.udpMuxSrflx,

client/internal/peer/conn.go

@@ -30,6 +30,7 @@ type ConnConfig struct {
 	// InterfaceBlackList is a list of machine interfaces that should be filtered out by ICE Candidate gathering
 	// (e.g. if eth0 is in the list, host candidate of this interface won't be used)
 	InterfaceBlackList   []string
+	DisableIPv6Discovery bool
 
 	Timeout time.Duration
 
@@ -145,9 +146,9 @@ func (conn *Conn) reCreateAgent() error {
 
 	failedTimeout := 6 * time.Second
 	var err error
-	conn.agent, err = ice.NewAgent(&ice.AgentConfig{
+	agentConfig := &ice.AgentConfig{
 		MulticastDNSMode: ice.MulticastDNSModeDisabled,
-		NetworkTypes:     []ice.NetworkType{ice.NetworkTypeUDP4},
+		NetworkTypes:     []ice.NetworkType{ice.NetworkTypeUDP4, ice.NetworkTypeUDP6},
 		Urls:             conn.config.StunTurn,
 		CandidateTypes:   []ice.CandidateType{ice.CandidateTypeHost, ice.CandidateTypeServerReflexive, ice.CandidateTypeRelay},
 		FailedTimeout:    &failedTimeout,
@@ -155,7 +156,14 @@ func (conn *Conn) reCreateAgent() error {
 		UDPMux:           conn.config.UDPMux,
 		UDPMuxSrflx:      conn.config.UDPMuxSrflx,
 		NAT1To1IPs:       conn.config.NATExternalIPs,
-	})
+	}
+
+	if conn.config.DisableIPv6Discovery {
+		agentConfig.NetworkTypes = []ice.NetworkType{ice.NetworkTypeUDP4}
+	}
+
+	conn.agent, err = ice.NewAgent(agentConfig)
+
 	if err != nil {
 		return err
 	}