Remove KCP (fixes #4737) (#4741)

lib/protocol/benchmark_test.go

@@ -9,7 +9,6 @@ import (
 	"testing"
 
 	"github.com/syncthing/syncthing/lib/dialer"
-	"github.com/xtaci/kcp-go"
 )
 
 func BenchmarkRequestsRawTCP(b *testing.B) {
@@ -29,25 +28,6 @@ func BenchmarkRequestsRawTCP(b *testing.B) {
 	benchmarkRequestsConnPair(b, conn0, conn1)
 }
 
-func BenchmarkRequestsRawKCP(b *testing.B) {
-	b.Skip("KCP broken")
-
-	// Benchmarks the rate at which we can serve requests over a single,
-	// unencrypted KCP channel over the loopback interface.
-
-	// Get a connected KCP pair
-	conn0, conn1, err := getKCPConnectionPair()
-	if err != nil {
-		b.Fatal(err)
-	}
-
-	defer conn0.Close()
-	defer conn1.Close()
-
-	// Bench it
-	benchmarkRequestsConnPair(b, conn0, conn1)
-}
-
 func BenchmarkRequestsTLSoTCP(b *testing.B) {
 	conn0, conn1, err := getTCPConnectionPair()
 	if err != nil {
@@ -58,18 +38,6 @@ func BenchmarkRequestsTLSoTCP(b *testing.B) {
 	benchmarkRequestsTLS(b, conn0, conn1)
 }
 
-func BenchmarkRequestsTLSoKCP(b *testing.B) {
-	b.Skip("KCP broken")
-
-	conn0, conn1, err := getKCPConnectionPair()
-	if err != nil {
-		b.Fatal(err)
-	}
-	defer conn0.Close()
-	defer conn1.Close()
-	benchmarkRequestsTLS(b, conn0, conn1)
-}
-
 func benchmarkRequestsTLS(b *testing.B, conn0, conn1 net.Conn) {
 	// Benchmarks the rate at which we can serve requests over a single,
 	// TLS encrypted channel over the loopback interface.
@@ -170,35 +138,6 @@ func getTCPConnectionPair() (net.Conn, net.Conn, error) {
 	return conn0, conn1, nil
 }
 
-func getKCPConnectionPair() (net.Conn, net.Conn, error) {
-	lst, err := kcp.Listen("127.0.0.1:0")
-	if err != nil {
-		return nil, nil, err
-	}
-
-	var conn0 net.Conn
-	var err0 error
-	done := make(chan struct{})
-	go func() {
-		conn0, err0 = lst.Accept()
-		close(done)
-	}()
-
-	// Dial the connection
-	conn1, err := kcp.Dial(lst.Addr().String())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	// Check any error from accept
-	<-done
-	if err0 != nil {
-		return nil, nil, err0
-	}
-
-	return conn0, conn1, nil
-}
-
 func negotiateTLS(cert tls.Certificate, conn0, conn1 net.Conn) (net.Conn, net.Conn) {
 	cfg := &tls.Config{
 		Certificates:           []tls.Certificate{cert},