tls: Disable clientsessioncache

The ClientCessionCache causes incompatibilities between go-dqlite
1.11.6 and 1.11.7.

go-dqlite 1.11.7 contains a new SimpleTLSConfig that eliminated
incompatibilities with go 1.19.6 and newer. However, it seems nodes
running go-dqlite versions older than 1.11.7 throw TLS errors when
communication with modern nodes if the ClientCessionCache is enabled.

So, disable the ClientCessionCache by default. Users can still opt to
enable it by adapting the client config returned by SimpleTLSConfig.

Signed-off-by: Mathieu Borderé <[email protected]>

app/tls.go

@@ -96,10 +96,9 @@ func SimpleListenTLSConfig(cert tls.Certificate, pool *x509.CertPool) *tls.Confi
 // A user can modify the returned config to suit their specifig needs.
 func SimpleDialTLSConfig(cert tls.Certificate, pool *x509.CertPool) *tls.Config {
 	config := &tls.Config{
-		MinVersion:         tls.VersionTLS12,
-		RootCAs:            pool,
-		Certificates:       []tls.Certificate{cert},
-		ClientSessionCache: tls.NewLRUClientSessionCache(256),
+		MinVersion:   tls.VersionTLS12,
+		RootCAs:      pool,
+		Certificates: []tls.Certificate{cert},
 	}
 
 	x509cert, err := x509.ParseCertificate(cert.Certificate[0])