From eb6e4a982d6044147d7613875a4ccf5c0e3c3764 Mon Sep 17 00:00:00 2001
From: dalbodeule <11470513+dalbodeule@users.noreply.github.com>
Date: Tue, 2 Dec 2025 23:33:42 +0900
Subject: [PATCH] [fix](client): ensure proper SNI hostname extraction in TLS
 config

- Updated `tlsCfg.ServerName` logic to extract and set hostname (DNS) from `ServerAddr` to comply with SNI requirements.
- Utilized `net.SplitHostPort` for accurate parsing of `host:port` format.
---
 cmd/client/main.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/cmd/client/main.go b/cmd/client/main.go
index 60dfa13..86e2b2a 100644
--- a/cmd/client/main.go
+++ b/cmd/client/main.go
@@ -5,6 +5,7 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"flag"
+	"net"
 	"os"
 	"strings"
 
@@ -118,7 +119,13 @@ func main() {
 	}
 	// DTLS 서버 측은 SNI(ServerName)가 HOP_SERVER_DOMAIN(cfg.Domain)과 일치하는지 검사하므로,
 	// 클라이언트 TLS 설정에도 반드시 도메인을 설정해준다.
-	tlsCfg.ServerName = finalCfg.Domain
+	//
+	// finalCfg.ServerAddr 가 "host:port" 형태이므로, SNI 에는 DNS(host) 부분만 넣어야 한다.
+	host := finalCfg.ServerAddr
+	if h, _, err := net.SplitHostPort(finalCfg.ServerAddr); err == nil && strings.TrimSpace(h) != "" {
+		host = h
+	}
+	tlsCfg.ServerName = host
 
 	client := dtls.NewPionClient(dtls.PionClientConfig{
 		Addr:      finalCfg.ServerAddr,