fix(chain): Copy returns wrong pointer, connection leaks in Connect/Handshake, deferred cancel accumulation in retry loops

- transport.go: Copy() returned original pointer instead of the allocated copy,
  causing data races and incorrect routing for multiplexed chains.
- route.go: Connect and Handshake failures in intermediate nodes leaked the
  returned connection. Handshake fix preserves the original Connect result
  (guaranteed non-nil) and closes both the Handshake return value and input.
- router.go: defer cancel() inside retry loops accumulated context timers
  across iterations. Wrapped each loop body in an IIFE so defer scopes
  per-iteration and timers are released immediately.

chain/route.go

@@ -271,20 +271,29 @@ func (r *chainRoute) connect(ctx context.Context, logger logger.Logger) (conn ne
 		}
 		cc, err = preNode.Options().Transport.Connect(ctx, cn, "tcp", addr)
 		if err != nil {
+			if cc != nil {
+				cc.Close()
+			}
 			cn.Close()
 			if marker != nil {
 				marker.Mark()
 			}
 			return
 		}
-		cc, err = node.Options().Transport.Handshake(ctx, cc)
+		var cc2 net.Conn
+		cc2, err = node.Options().Transport.Handshake(ctx, cc)
 		if err != nil {
+			if cc2 != nil {
+				cc2.Close()
+			}
+			cc.Close()
 			cn.Close()
 			if marker != nil {
 				marker.Mark()
 			}
 			return
 		}
+		cc = cc2
 		if marker != nil {
 			marker.Reset()
 		}

chain/router.go

@@ -90,6 +90,7 @@ func (r *Router) dial(ctx context.Context, network, address string, log logger.L
 	log.Debugf("dial %s/%s", address, network)
 
 	for i := 0; i < count; i++ {
+		func() {
 			ctx := ctx
 			if r.options.Timeout > 0 {
 				var cancel context.CancelFunc
@@ -106,7 +107,7 @@ func (r *Router) dial(ctx context.Context, network, address string, log logger.L
 			ipAddr, err = xnet.Resolve(ctx, "ip", address, r.options.Resolver, r.options.HostMapper, log)
 			if err != nil {
 				log.Error(err)
-			break
+				return
 			}
 
 			if buf != nil {
@@ -139,9 +140,13 @@ func (r *Router) dial(ctx context.Context, network, address string, log logger.L
 				}, callerOpts...)...,
 			)
 			if err == nil {
-			break
+				return
 			}
 			log.Errorf("route(retry=%d) %s", i, err)
+		}()
+		if conn != nil || err == nil {
+			break
+		}
 	}
 
 	return
@@ -160,6 +165,7 @@ func (r *Router) Bind(ctx context.Context, network, address string, opts ...chai
 	log.Debugf("bind on %s/%s", address, network)
 
 	for i := 0; i < count; i++ {
+		func() {
 			ctx := ctx
 			if r.options.Timeout > 0 {
 				var cancel context.CancelFunc
@@ -190,9 +196,13 @@ func (r *Router) Bind(ctx context.Context, network, address string, opts ...chai
 			}
 			ln, err = route.Bind(ctx, network, address, opts...)
 			if err == nil {
-			break
+				return
 			}
 			log.Errorf("route(retry=%d) %s", i, err)
+		}()
+		if ln != nil || err == nil {
+			break
+		}
 	}
 
 	return

chain/transport.go

@@ -102,5 +102,5 @@ func (tr *Transport) Options() *chain.TransportOptions {
 func (tr *Transport) Copy() chain.Transporter {
 	tr2 := &Transport{}
 	*tr2 = *tr
-	return tr
+	return tr2
 }