From 13bad86c3b1570f5e203a29a82afd4b843d612a1 Mon Sep 17 00:00:00 2001
From: dyhkwong <50692134+dyhkwong@users.noreply.github.com>
Date: Sun, 13 Oct 2024 02:59:43 +0800
Subject: [PATCH] Fix the use of ServerName in ECH config (#3188)

---
 transport/internet/tls/ech.go | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/transport/internet/tls/ech.go b/transport/internet/tls/ech.go
index 8b012250e86..41be26d9db8 100644
--- a/transport/internet/tls/ech.go
+++ b/transport/internet/tls/ech.go
@@ -24,10 +24,11 @@ func ApplyECH(c *Config, config *tls.Config) error {
 	if len(c.EchConfig) > 0 {
 		ECHConfig = c.EchConfig
 	} else { // ECH config > DOH lookup
-		if config.ServerName == "" {
-			return newError("Using DOH for ECH needs serverName")
+		addr := net.ParseAddress(config.ServerName)
+		if !addr.Family().IsDomain() {
+			return newError("Using DOH for ECH needs SNI")
 		}
-		ECHConfig, err = QueryRecord(c.ServerName, c.Ech_DOHserver)
+		ECHConfig, err = QueryRecord(addr.Domain(), c.Ech_DOHserver)
 		if err != nil {
 			return err
 		}