Add ECH keypair generator

cmd/sing-box/cmd_generate_ech.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"os"
+
+	"github.com/sagernet/sing-box/common/tls"
+	"github.com/sagernet/sing-box/log"
+
+	"github.com/spf13/cobra"
+)
+
+var pqSignatureSchemesEnabled bool
+
+var commandGenerateECHKeyPair = &cobra.Command{
+	Use:   "ech-keypair <plain_server_name>",
+	Short: "Generate TLS ECH key pair",
+	Args:  cobra.ExactArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		err := generateECHKeyPair(args[0])
+		if err != nil {
+			log.Fatal(err)
+		}
+	},
+}
+
+func init() {
+	commandGenerateECHKeyPair.Flags().BoolVar(&pqSignatureSchemesEnabled, "pq-signature-schemes-enabled", false, "Enable PQ signature schemes")
+	commandGenerate.AddCommand(commandGenerateECHKeyPair)
+}
+
+func generateECHKeyPair(serverName string) error {
+	configPem, keyPem, err := tls.ECHKeygenDefault(serverName, pqSignatureSchemesEnabled)
+	if err != nil {
+		return err
+	}
+	os.Stdout.WriteString(configPem)
+	os.Stdout.WriteString(keyPem)
+	return nil
+}