lib/connections, vendor: Change KCP mux to SMUX

Closes #4032

lib/connections/config.go

@@ -7,10 +7,9 @@
 package connections
 
 import (
-	"io/ioutil"
 	"time"
 
-	"github.com/hashicorp/yamux"
+	"github.com/xtaci/smux"
 )
 
 const (
@@ -25,12 +24,10 @@ const (
 )
 
 var (
-	yamuxConfig = &yamux.Config{
-		AcceptBacklog:          256,
-		EnableKeepAlive:        true,
-		KeepAliveInterval:      30 * time.Second,
-		ConnectionWriteTimeout: 10 * time.Second,
-		MaxStreamWindowSize:    256 * 1024,
-		LogOutput:              ioutil.Discard,
+	smuxConfig = &smux.Config{
+		KeepAliveInterval: 10 * time.Second,
+		KeepAliveTimeout:  30 * time.Second,
+		MaxFrameSize:      4096,
+		MaxReceiveBuffer:  4 * 1024 * 1024,
 	}
 )

lib/connections/kcp_dial.go

@@ -11,10 +11,10 @@ import (
 	"net/url"
 	"time"
 
-	"github.com/hashicorp/yamux"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/xtaci/kcp-go"
+	"github.com/xtaci/smux"
 )
 
 func init() {
@@ -56,7 +56,7 @@ func (d *kcpDialer) Dial(id protocol.DeviceID, uri *url.URL) (internalConn, erro
 	conn.SetWindowSize(opts.KCPSendWindowSize, opts.KCPReceiveWindowSize)
 	conn.SetNoDelay(boolInt(opts.KCPNoDelay), opts.KCPUpdateIntervalMs, boolInt(opts.KCPFastResend), boolInt(!opts.KCPCongestionControl))
 
-	ses, err := yamux.Client(conn, yamuxConfig)
+	ses, err := smux.Client(conn, smuxConfig)
 	if err != nil {
 		conn.Close()
 		return internalConn{}, err

lib/connections/kcp_listen.go

@@ -16,10 +16,10 @@ import (
 
 	"github.com/AudriusButkevicius/pfilter"
 	"github.com/ccding/go-stun/stun"
-	"github.com/hashicorp/yamux"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/nat"
 	"github.com/xtaci/kcp-go"
+	"github.com/xtaci/smux"
 )
 
 func init() {
@@ -116,16 +116,16 @@ func (t *kcpListener) Serve() {
 
 		l.Debugln("connect from", conn.RemoteAddr())
 
-		ses, err := yamux.Server(conn, yamuxConfig)
+		ses, err := smux.Server(conn, smuxConfig)
 		if err != nil {
-			l.Debugln("yamux server:", err)
+			l.Debugln("smux server:", err)
 			conn.Close()
 			continue
 		}
 
 		stream, err := ses.AcceptStream()
 		if err != nil {
-			l.Debugln("yamux accept:", err)
+			l.Debugln("smux accept:", err)
 			ses.Close()
 			continue
 		}

lib/connections/kcp_misc.go

@@ -16,7 +16,7 @@ import (
 	"time"
 
 	"github.com/AudriusButkevicius/pfilter"
-	"github.com/hashicorp/yamux"
+	"github.com/xtaci/smux"
 )
 
 var (
@@ -162,8 +162,8 @@ func (f *stunFilter) reap() {
 }
 
 type sessionClosingStream struct {
-	*yamux.Stream
-	session *yamux.Session
+	*smux.Stream
+	session *smux.Session
 }
 
 func (w *sessionClosingStream) Close() error {