fix: 中转添加udp relay

cmd/internal/peer/kcp_client_test.go

@@ -293,12 +293,12 @@ func TestKCPClientsExchangeMessagesViaUDPRelayToSingleHub(t *testing.T) {
 	relayWG.Add(1)
 	go func() {
 		defer relayWG.Done()
-		if serveErr := relay.Serve(); serveErr != nil {
+		if serveErr := relay.Serve(); serveErr != nil && !isExpectedKCPRelayServeExit(serveErr) {
 			t.Errorf("relay.Serve() error = %v", serveErr)
 		}
 	}()
 	defer func() {
-		_ = relayConn.Close()
+		_ = relay.Close()
 		relayWG.Wait()
 	}()
 

cmd/internal/server/udp_relay.go

@@ -9,30 +9,29 @@ import (
 	"omnisocketgo/cmd/internal/protocol"
 )
 
-// udpRelayBufSize 是 relay 接收缓冲区大小，与 UDP transport 层保持一致。
 const udpRelayBufSize = protocol.MaxFrameSize + 1024
 
-// UDPRelay 是一个透明的双向 UDP 转发器。
+// UDPRelay transparently forwards UDP datagrams between one downstream client
-// 它在下游（客户端 A）和上游（server D）之间原样转发 UDP 数据报，
+// and a fixed upstream server.
-// 不解析也不修改协议内容。
 type UDPRelay struct {
-	downstream *net.UDPConn // 监听端口，等待下游客户端连接
+	downstream net.PacketConn
-	upstream   *net.UDPConn // 连接到上游 server（connected socket）
+	upstream   *net.UDPConn
 
 	mu         sync.RWMutex
-	clientAddr *net.UDPAddr // 下游客户端地址，从第一个下游包学习
+	clientAddr net.Addr
 }
 
-// NewUDPRelay 创建一个新的 UDP relay。
+// NewUDPRelay creates a relay that listens on listenConn and forwards all
-// listenConn 是已经绑定好的监听 socket（供下游客户端连接），
+// traffic to upstreamAddr.
-// upstreamAddr 是上游 server D 的地址。
+func NewUDPRelay(listenConn net.PacketConn, upstreamAddr *net.UDPAddr) (*UDPRelay, error) {
-func NewUDPRelay(listenConn *net.UDPConn, upstreamAddr string) (*UDPRelay, error) {
+	if listenConn == nil {
-	udpUpstreamAddr, err := net.ResolveUDPAddr("udp", upstreamAddr)
+		return nil, fmt.Errorf("relay: listen conn is required")
-	if err != nil {
+	}
-		return nil, fmt.Errorf("relay: resolve upstream addr %s: %w", upstreamAddr, err)
+	if upstreamAddr == nil {
+		return nil, fmt.Errorf("relay: upstream addr is required")
 	}
 
-	upstreamConn, err := net.DialUDP("udp", nil, udpUpstreamAddr)
+	upstreamConn, err := net.DialUDP("udp", nil, upstreamAddr)
 	if err != nil {
 		return nil, fmt.Errorf("relay: dial upstream %s: %w", upstreamAddr, err)
 	}
@@ -43,7 +42,8 @@ func NewUDPRelay(listenConn *net.UDPConn, upstreamAddr string) (*UDPRelay, error
 	}, nil
 }
 
-// Serve 启动双向转发循环，阻塞直到任一方向出错。
+// Serve starts bidirectional forwarding and blocks until either direction
+// exits with an error.
 func (r *UDPRelay) Serve() error {
 	errCh := make(chan error, 2)
 
@@ -55,23 +55,21 @@ func (r *UDPRelay) Serve() error {
 	}()
 
 	err := <-errCh
-	// 关闭两个 conn 让另一个 goroutine 也退出
 	_ = r.downstream.Close()
 	_ = r.upstream.Close()
 	return err
 }
 
-// forwardDownstreamToUpstream 从下游读取并转发到上游。
 func (r *UDPRelay) forwardDownstreamToUpstream() error {
 	buf := make([]byte, udpRelayBufSize)
 	for {
-		n, addr, err := r.downstream.ReadFromUDP(buf)
+		n, addr, err := r.downstream.ReadFrom(buf)
 		if err != nil {
 			return fmt.Errorf("relay: read downstream: %w", err)
 		}
 
 		r.mu.Lock()
-		r.clientAddr = addr
+		r.clientAddr = cloneRelayAddr(addr)
 		r.mu.Unlock()
 
 		if _, err := r.upstream.Write(buf[:n]); err != nil {
@@ -82,7 +80,6 @@ func (r *UDPRelay) forwardDownstreamToUpstream() error {
 	}
 }
 
-// forwardUpstreamToDownstream 从上游读取并转发到下游。
 func (r *UDPRelay) forwardUpstreamToDownstream() error {
 	buf := make([]byte, udpRelayBufSize)
 	for {
@@ -92,7 +89,7 @@ func (r *UDPRelay) forwardUpstreamToDownstream() error {
 		}
 
 		r.mu.RLock()
-		addr := r.clientAddr
+		addr := cloneRelayAddr(r.clientAddr)
 		r.mu.RUnlock()
 
 		if addr == nil {
@@ -100,7 +97,7 @@ func (r *UDPRelay) forwardUpstreamToDownstream() error {
 			continue
 		}
 
-		if _, err := r.downstream.WriteToUDP(buf[:n], addr); err != nil {
+		if _, err := r.downstream.WriteTo(buf[:n], addr); err != nil {
 			return fmt.Errorf("relay: write downstream to %s: %w", addr, err)
 		}
 
@@ -108,7 +105,6 @@ func (r *UDPRelay) forwardUpstreamToDownstream() error {
 	}
 }
 
-// Close 关闭 relay 的上下游连接。
 func (r *UDPRelay) Close() error {
 	err1 := r.downstream.Close()
 	err2 := r.upstream.Close()

cmd/internal/server/udp_relay_test.go

@@ -14,22 +14,15 @@ import (
 	"omnisocketgo/cmd/internal/transport"
 )
 
-// TestUDPRelayKCPForwardAndReturn 验证 KCP 通过 UDP relay 的完整双向转发路径：
-// peer-b -> D(KCP hub) -> C(UDP relay) -> peer-a 以及反向。
 func TestUDPRelayKCPForwardAndReturn(t *testing.T) {
-	// 启动 D（KCP Hub）
 	hub, hubAddr, hubCleanup := startKCPHubForRelay(t)
 	defer hubCleanup()
 
-	// 启动 C（UDP Relay），upstream 指向 D
 	relayAddr := startUDPRelay(t, hubAddr)
 
-	// peer-b 直连 D（KCP）
 	peerBConn := dialKCPPeer(t, hubAddr)
-	// peer-a 连 C（通过 relay 间接连到 D）
 	peerAConn := dialKCPPeer(t, relayAddr)
 
-	// 注册 peer-b
 	if err := peerBConn.Send(protocol.Message{
 		Type: protocol.MessageTypeRegister,
 		From: "peer-b",
@@ -37,8 +30,6 @@ func TestUDPRelayKCPForwardAndReturn(t *testing.T) {
 	}); err != nil {
 		t.Fatalf("peerB register: %v", err)
 	}
-
-	// 注册 peer-a（通过 relay）
 	if err := peerAConn.Send(protocol.Message{
 		Type: protocol.MessageTypeRegister,
 		From: "peer-a",
@@ -51,7 +42,6 @@ func TestUDPRelayKCPForwardAndReturn(t *testing.T) {
 		return hub.HasPeer("peer-a") && hub.HasPeer("peer-b")
 	}, "both peers to be registered")
 
-	// peer-b -> peer-a（路径: B -> D -> C -> A）
 	if err := peerBConn.Send(protocol.Message{
 		Type: protocol.MessageTypeText,
 		ID:   1,
@@ -76,19 +66,12 @@ func TestUDPRelayKCPForwardAndReturn(t *testing.T) {
 		t.Fatalf("message body = %q, want %q", string(msg.Body), "hello from peer-b")
 	}
 
-	// peer-a -> peer-b（路径: A -> C -> D -> B）
 	if err := peerAConn.Send(protocol.Message{
 		Type: protocol.MessageTypeText,
 		ID:   2,
 		From: "peer-a",
 		To:   "peer-b",
-		Body: []byte("reply from peer-单个 downstream peer 通过 relay 连到 KCP server”这条
+		Body: []byte("reply from peer-a"),
-  链路是成立的，转发逻辑本身没有明显的地址错误。cmd/internal/server/udp_relay.go 里就是原
-  样双向转发，下游来的包会记录 clientAddr 并写给上游，上游回来的包再写回这个 clientAddr。
-  关键代码在 cmd/internal/server/udp_relay.go:68 和 cmd/internal/server/udp_relay.go:89。
-
-  还有一个关键事实：kcppeer 里那句 connected to ... as ... (KCP) 不能证明 peer-a 真的在
-  hub 注册成功a"),
 	}); err != nil {
 		t.Fatalf("peerA send text: %v", err)
 	}
@@ -108,7 +91,6 @@ func TestUDPRelayKCPForwardAndReturn(t *testing.T) {
 	}
 }
 
-// TestUDPRelayKCPFileMessage 验证通过 relay 转发 KCP 文件消息。
 func TestUDPRelayKCPFileMessage(t *testing.T) {
 	hub, hubAddr, hubCleanup := startKCPHubForRelay(t)
 	defer hubCleanup()
@@ -118,16 +100,20 @@ func TestUDPRelayKCPFileMessage(t *testing.T) {
 	peerBConn := dialKCPPeer(t, hubAddr)
 	peerAConn := dialKCPPeer(t, relayAddr)
 
-	_ = peerBConn.Send(protocol.Message{
+	if err := peerBConn.Send(protocol.Message{
 		Type: protocol.MessageTypeRegister,
 		From: "peer-b",
 		To:   protocol.ServerPeerID,
-	})
+	}); err != nil {
-	_ = peerAConn.Send(protocol.Message{
+		t.Fatalf("peerB register: %v", err)
+	}
+	if err := peerAConn.Send(protocol.Message{
 		Type: protocol.MessageTypeRegister,
 		From: "peer-a",
 		To:   protocol.ServerPeerID,
-	})
+	}); err != nil {
+		t.Fatalf("peerA register: %v", err)
+	}
 
 	waitForRelay(t, func() bool {
 		return hub.HasPeer("peer-a") && hub.HasPeer("peer-b")
@@ -154,18 +140,11 @@ func TestUDPRelayKCPFileMessage(t *testing.T) {
 	if msg.FileName != "test.bin" {
 		t.Fatalf("file name = %q, want %q", msg.FileName, "test.bin")
 	}
-	if len(msg.Body) != 4 || msg.Body[0] != 0xDE {
+	if string(msg.Body) != string([]byte{0xDE, 0xAD, 0xBE, 0xEF}) {
-		t.Fatalf("file body mismatch: 单个 downstream peer 通过 relay 连到 KCP server”这条
+		t.Fatalf("file body = %v, want %v", msg.Body, []byte{0xDE, 0xAD, 0xBE, 0xEF})
-  链路是成立的，转发逻辑本身没有明显的地址错误。cmd/internal/server/udp_relay.go 里就是原
-  样双向转发，下游来的包会记录 clientAddr 并写给上游，上游回来的包再写回这个 clientAddr。
-  关键代码在 cmd/internal/server/udp_relay.go:68 和 cmd/internal/server/udp_relay.go:89。
-
-  还有一个关键事实：kcppeer 里那句 connected to ... as ... (KCP) 不能证明 peer-a 真的在
-  hub 注册成功got %v", msg.Body)
 	}
 }
 
-// startKCPHubForRelay 启动一个 KCP hub server，返回 hub、监听地址和 cleanup 函数。
 func startKCPHubForRelay(t *testing.T) (*KCPHub, string, func()) {
 	t.Helper()
 
@@ -222,7 +201,6 @@ func startKCPHubForRelay(t *testing.T) (*KCPHub, string, func()) {
 	return hub, listener.Addr().String(), cleanup
 }
 
-// dialKCPPeer 创建一条到指定地址的 KCP 连接，用于测试。
 func dialKCPPeer(t *testing.T, serverAddr string) *transport.KCPConn {
 	t.Helper()
 
@@ -244,38 +222,42 @@ func dialKCPPeer(t *testing.T, serverAddr string) *transport.KCPConn {
 	return conn
 }
 
-// startUDPRelay 创建并启动一个 UDPRelay，返回其监听地址字符串。
 func startUDPRelay(t *testing.T, upstreamAddr string) string {
 	t.Helper()
 
-	addr, err := net.ResolveUDPAddr("udp", "127.0.0.1:0")
+	remoteAddr, err := net.ResolveUDPAddr("udp", upstreamAddr)
 	if err != nil {
-		t.Fatalf("ResolveUDPAddr() error = %v", err)
+		t.Fatalf("ResolveUDPAddr(%s) error = %v", upstreamAddr, err)
 	}
 
-	conn, err := net.ListenUDP("udp", addr)
+	conn, err := net.ListenPacket("udp", "127.0.0.1:0")
 	if err != nil {
-		t.Fatalf("ListenUDP() error = %v", err)
+		t.Fatalf("ListenPacket() error = %v", err)
 	}
 
-	relay, err := NewUDPRelay(conn, upstreamAddr)
+	relay, err := NewUDPRelay(conn, remoteAddr)
 	if err != nil {
 		_ = conn.Close()
 		t.Fatalf("NewUDPRelay() error = %v", err)
 	}
 
+	var wg sync.WaitGroup
+	wg.Add(1)
 	go func() {
-		_ = relay.Serve()
+		defer wg.Done()
+		if serveErr := relay.Serve(); serveErr != nil && !isExpectedRelayServeExit(serveErr) {
+			t.Errorf("relay.Serve() error = %v", serveErr)
+		}
 	}()
 
 	t.Cleanup(func() {
 		_ = relay.Close()
+		wg.Wait()
 	})
 
 	return conn.LocalAddr().String()
 }
 
-// waitForRelay 轮询等待条件满足，超时则 fail。
 func waitForRelay(t *testing.T, condition func() bool, description string) {
 	t.Helper()
 

cmd/kcpserver/main.go

@@ -165,6 +165,7 @@ func runUDPRelayServer(listenAddr, remoteAddr string) {
 
 	relay, err := server.NewUDPRelay(conn, remote)
 	if err != nil {
+		_ = conn.Close()
 		log.Fatalf("create udp relay: %v", err)
 	}
 

cmd/udprelay/main.go

@@ -13,17 +13,17 @@ func main() {
 	upstreamAddr := flag.String("upstream", "127.0.0.1:9002", "upstream KCP server address (server D)")
 	flag.Parse()
 
-	udpAddr, err := net.ResolveUDPAddr("udp", *listenAddr)
+	upstreamUDPAddr, err := net.ResolveUDPAddr("udp", *upstreamAddr)
 	if err != nil {
-		log.Fatalf("resolve listen address %s: %v", *listenAddr, err)
+		log.Fatalf("resolve upstream address %s: %v", *upstreamAddr, err)
 	}
 
-	conn, err := net.ListenUDP("udp", udpAddr)
+	conn, err := net.ListenPacket("udp", *listenAddr)
 	if err != nil {
 		log.Fatalf("listen udp on %s: %v", *listenAddr, err)
 	}
 
-	relay, err := server.NewUDPRelay(conn, *upstreamAddr)
+	relay, err := server.NewUDPRelay(conn, upstreamUDPAddr)
 	if err != nil {
 		_ = conn.Close()
 		log.Fatalf("create udp relay: %v", err)