cmd/syncthing: Enable KCP by default

Also, use upstream library, as my changes have been merged.

lib/config/config.go

@@ -48,11 +48,8 @@ var (
 	DefaultListenAddresses = []string{
 		util.Address("tcp", net.JoinHostPort("0.0.0.0", strconv.Itoa(DefaultTCPPort))),
 		"dynamic+https://relays.syncthing.net/endpoint",
+		util.Address("kcp", net.JoinHostPort("0.0.0.0", strconv.Itoa(DefaultKCPPort))),
 	}
-	// DefaultKCPListenAddress gets added to the default listen address set
-	// when the appropriate feature flag is set. Feature flag stuff to be
-	// removed later.
-	DefaultKCPListenAddress = util.Address("kcp", net.JoinHostPort("0.0.0.0", strconv.Itoa(DefaultKCPPort)))
 	// DefaultDiscoveryServersV4 should be substituted when the configuration
 	// contains <globalAnnounceServer>default-v4</globalAnnounceServer>.
 	DefaultDiscoveryServersV4 = []string{

lib/config/config_test.go

@@ -68,7 +68,6 @@ func TestDefaultValues(t *testing.T) {
 		WeakHashSelectionMethod: WeakHashAuto,
 		StunKeepaliveS:          24,
 		StunServers:             []string{"default"},
-		DefaultKCPEnabled:       false,
 		KCPCongestionControl:    true,
 		KCPReceiveWindowSize:    128,
 		KCPSendWindowSize:       128,
@@ -214,7 +213,6 @@ func TestOverriddenValues(t *testing.T) {
 		WeakHashSelectionMethod: WeakHashNever,
 		StunKeepaliveS:          10,
 		StunServers:             []string{"a.stun.com", "b.stun.com"},
-		DefaultKCPEnabled:       true,
 		KCPCongestionControl:    false,
 		KCPReceiveWindowSize:    1280,
 		KCPSendWindowSize:       1280,

lib/config/optionsconfiguration.go

@@ -134,7 +134,6 @@ type OptionsConfiguration struct {
 	WeakHashSelectionMethod WeakHashSelectionMethod `xml:"weakHashSelectionMethod" json:"weakHashSelectionMethod"`
 	StunServers             []string                `xml:"stunServer" json:"stunServers" default:"default"`
 	StunKeepaliveS          int                     `xml:"stunKeepaliveSeconds" json:"stunKeepaliveSeconds" default:"24"`
-	DefaultKCPEnabled       bool                    `xml:"defaultKCPEnabled" json:"defaultKCPEnabled" default:"false"`
 	KCPNoDelay              bool                    `xml:"kcpNoDelay" json:"kcpNoDelay" default:"false"`
 	KCPUpdateIntervalMs     int                     `xml:"kcpUpdateIntervalMs" json:"kcpUpdateIntervalMs" default:"25"`
 	KCPFastResend           bool                    `xml:"kcpFastResend" json:"kcpFastResend" default:"false"`

lib/config/testdata/overridenvalues.xml

@@ -38,7 +38,6 @@
         <stunKeepaliveSeconds>10</stunKeepaliveSeconds>
         <stunServer>a.stun.com</stunServer>
         <stunServer>b.stun.com</stunServer>
-        <defaultKCPEnabled>true</defaultKCPEnabled>
         <kcpCongestionControl>false</kcpCongestionControl>
         <kcpReceiveWindowSize>1280</kcpReceiveWindowSize>
         <kcpSendWindowSize>1280</kcpSendWindowSize>

lib/config/wrapper.go

@@ -423,9 +423,6 @@ func (w *Wrapper) ListenAddresses() []string {
 		switch addr {
 		case "default":
 			addresses = append(addresses, DefaultListenAddresses...)
-			if w.cfg.Options.DefaultKCPEnabled { // temporary feature flag
-				addresses = append(addresses, DefaultKCPListenAddress)
-			}
 		default:
 			addresses = append(addresses, addr)
 		}