Add ECH keypair generator

common/tls/ech_stub.go

@@ -10,10 +10,16 @@ import (
 	E "github.com/sagernet/sing/common/exceptions"
 )
 
+var errECHNotIncluded = E.New(`ECH is not included in this build, rebuild with -tags with_ech`)
+
 func NewECHServer(ctx context.Context, logger log.Logger, options option.InboundTLSOptions) (ServerConfig, error) {
-	return nil, E.New(`ECH is not included in this build, rebuild with -tags with_ech`)
+	return nil, errECHNotIncluded
 }
 
 func NewECHClient(ctx context.Context, serverAddress string, options option.OutboundTLSOptions) (Config, error) {
-	return nil, E.New(`ECH is not included in this build, rebuild with -tags with_ech`)
+	return nil, errECHNotIncluded
+}
+
+func ECHKeygenDefault(host string, pqSignatureSchemesEnabled bool) (configPem string, keyPem string, err error) {
+	return "", "", errECHNotIncluded
 }