fix(agent): retire replaced tunnel sessions (#541)

go-backend/internal/http/handler/security_utils.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"fmt"
 	"net"
+	"net/netip"
 	"strings"
 )
 
@@ -75,6 +76,12 @@ func IsValidNodeAddress(addr string) error {
 	if strings.ContainsAny(addr, "/?") {
 		return fmt.Errorf("address must not contain path or query parameters")
 	}
+	// A bare IPv6 literal contains multiple colons, so net.SplitHostPort treats
+	// it as a malformed host:port pair. Accept IP literals before attempting
+	// host:port parsing; netip also handles scoped IPv6 addresses.
+	if _, err := netip.ParseAddr(addr); err == nil {
+		return nil
+	}
 
 	_, _, err := net.SplitHostPort(addr)
 	if err != nil {

go-backend/internal/http/handler/security_utils_test.go

@@ -0,0 +1,46 @@
+package handler
+
+import "testing"
+
+func TestIssue515IsValidNodeAddressAcceptsBareIPv6(t *testing.T) {
+	for _, addr := range []string{
+		"2001:db8::1",
+		"::1",
+		"fe80::1%eth0",
+	} {
+		t.Run(addr, func(t *testing.T) {
+			if err := IsValidNodeAddress(addr); err != nil {
+				t.Fatalf("expected bare IPv6 address %q to be accepted: %v", addr, err)
+			}
+		})
+	}
+}
+
+func TestIsValidNodeAddressKeepsExistingAddressForms(t *testing.T) {
+	for _, addr := range []string{
+		"203.0.113.10",
+		"node.example.com",
+		"node.example.com:6365",
+		"[2001:db8::1]:6365",
+	} {
+		t.Run(addr, func(t *testing.T) {
+			if err := IsValidNodeAddress(addr); err != nil {
+				t.Fatalf("expected node address %q to be accepted: %v", addr, err)
+			}
+		})
+	}
+}
+
+func TestIsValidNodeAddressRejectsURLComponents(t *testing.T) {
+	for _, addr := range []string{
+		"https://node.example.com",
+		"node.example.com/path",
+		"node.example.com?transport=tcp",
+	} {
+		t.Run(addr, func(t *testing.T) {
+			if err := IsValidNodeAddress(addr); err == nil {
+				t.Fatalf("expected node address %q to be rejected", addr)
+			}
+		})
+	}
+}

go-gost/x/chain/chain.go

@@ -2,6 +2,8 @@ package chain
 
 import (
 	"context"
+	"errors"
+	"io"
 
 	"github.com/go-gost/core/chain"
 	"github.com/go-gost/core/hop"
@@ -38,11 +40,12 @@ type chainNamer interface {
 }
 
 type Chain struct {
-	name     string
-	hops     []hop.Hop
-	marker   selector.Marker
-	metadata metadata.Metadata
-	logger   logger.Logger
+	name      string
+	hops      []hop.Hop
+	ownedHops []hop.Hop
+	marker    selector.Marker
+	metadata  metadata.Metadata
+	logger    logger.Logger
 }
 
 func NewChain(name string, opts ...ChainOption) *Chain {
@@ -61,8 +64,15 @@ func NewChain(name string, opts ...ChainOption) *Chain {
 	}
 }
 
-func (c *Chain) AddHop(hop hop.Hop) {
+func (c *Chain) AddHop(hop hop.Hop, owned ...bool) {
 	c.hops = append(c.hops, hop)
+	isOwned := true
+	if len(owned) > 0 {
+		isOwned = owned[0]
+	}
+	if isOwned {
+		c.ownedHops = append(c.ownedHops, hop)
+	}
 }
 
 // Metadata implements metadata.Metadatable interface.
@@ -112,6 +122,36 @@ func (c *Chain) Route(ctx context.Context, network, address string, opts ...chai
 	return rt
 }
 
+// Retire gracefully drains resources owned by a chain that has been replaced.
+func (c *Chain) Retire() {
+	if c == nil {
+		return
+	}
+	for _, h := range c.ownedHops {
+		if retirer, ok := h.(interface{ Retire() }); ok {
+			retirer.Retire()
+			continue
+		}
+		if closer, ok := h.(io.Closer); ok {
+			_ = closer.Close()
+		}
+	}
+}
+
+// Close immediately releases all resources owned by the chain.
+func (c *Chain) Close() error {
+	if c == nil {
+		return nil
+	}
+	var errs []error
+	for _, h := range c.ownedHops {
+		if closer, ok := h.(io.Closer); ok {
+			errs = append(errs, closer.Close())
+		}
+	}
+	return errors.Join(errs...)
+}
+
 type chainGroup struct {
 	chains   []chain.Chainer
 	selector selector.Selector[chain.Chainer]

go-gost/x/chain/chain_test.go

@@ -0,0 +1,64 @@
+package chain
+
+import (
+	"context"
+	"testing"
+
+	corechain "github.com/go-gost/core/chain"
+	corehop "github.com/go-gost/core/hop"
+)
+
+type lifecycleTestHop struct {
+	selected int
+	retired  int
+	closed   int
+}
+
+func (h *lifecycleTestHop) Select(context.Context, ...corehop.SelectOption) *corechain.Node {
+	h.selected++
+	return nil
+}
+
+func (h *lifecycleTestHop) Retire() {
+	h.retired++
+}
+
+func (h *lifecycleTestHop) Close() error {
+	h.closed++
+	return nil
+}
+
+func TestChainRoutesThroughSharedHopWithoutOwningLifecycle(t *testing.T) {
+	hop := &lifecycleTestHop{}
+	chain := NewChain("shared-hop")
+	chain.AddHop(hop, false)
+
+	if route := chain.Route(context.Background(), "tcp", "example.com:443"); route == nil {
+		t.Fatal("route is nil")
+	}
+	if hop.selected != 1 {
+		t.Fatalf("shared hop selected %d times, want 1", hop.selected)
+	}
+
+	chain.Retire()
+	if err := chain.Close(); err != nil {
+		t.Fatalf("close chain: %v", err)
+	}
+	if hop.retired != 0 || hop.closed != 0 {
+		t.Fatalf("shared hop lifecycle changed: retired=%d closed=%d", hop.retired, hop.closed)
+	}
+}
+
+func TestChainRetiresAndClosesOwnedHop(t *testing.T) {
+	hop := &lifecycleTestHop{}
+	chain := NewChain("owned-hop")
+	chain.AddHop(hop)
+
+	chain.Retire()
+	if err := chain.Close(); err != nil {
+		t.Fatalf("close chain: %v", err)
+	}
+	if hop.retired != 1 || hop.closed != 1 {
+		t.Fatalf("owned hop lifecycle: retired=%d closed=%d, want 1/1", hop.retired, hop.closed)
+	}
+}

go-gost/x/chain/transport.go

@@ -2,6 +2,8 @@ package chain
 
 import (
 	"context"
+	"errors"
+	"io"
 	"net"
 
 	"github.com/go-gost/core/chain"
@@ -102,5 +104,34 @@ func (tr *Transport) Options() *chain.TransportOptions {
 func (tr *Transport) Copy() chain.Transporter {
 	tr2 := &Transport{}
 	*tr2 = *tr
-	return tr
+	return tr2
+}
+
+// Retire prevents long-lived dialer sessions owned by an obsolete chain from
+// accepting new streams while allowing existing streams to drain.
+func (tr *Transport) Retire() {
+	if tr == nil {
+		return
+	}
+	if retirer, ok := tr.dialer.(interface{ Retire() }); ok {
+		retirer.Retire()
+	}
+	if retirer, ok := tr.connector.(interface{ Retire() }); ok {
+		retirer.Retire()
+	}
+}
+
+// Close immediately releases transport-owned dialer and connector resources.
+func (tr *Transport) Close() error {
+	if tr == nil {
+		return nil
+	}
+	var errs []error
+	if closer, ok := tr.dialer.(io.Closer); ok {
+		errs = append(errs, closer.Close())
+	}
+	if closer, ok := tr.connector.(io.Closer); ok {
+		errs = append(errs, closer.Close())
+	}
+	return errors.Join(errs...)
 }

go-gost/x/chain/transport_test.go

@@ -0,0 +1,45 @@
+package chain
+
+import (
+	"context"
+	"net"
+	"testing"
+
+	corechain "github.com/go-gost/core/chain"
+)
+
+type copyTestRoute struct{}
+
+func (copyTestRoute) Dial(context.Context, string, string, ...corechain.DialOption) (net.Conn, error) {
+	return nil, nil
+}
+
+func (copyTestRoute) Bind(context.Context, string, string, ...corechain.BindOption) (net.Listener, error) {
+	return nil, nil
+}
+
+func (copyTestRoute) Nodes() []*corechain.Node {
+	return nil
+}
+
+func TestTransportCopyReturnsIndependentTransport(t *testing.T) {
+	originalRoute := copyTestRoute{}
+	replacementRoute := &copyTestRoute{}
+	original := NewTransport(nil, nil, corechain.RouteTransportOption(originalRoute))
+
+	copied, ok := original.Copy().(*Transport)
+	if !ok {
+		t.Fatalf("copy type = %T, want *Transport", original.Copy())
+	}
+	if copied == original {
+		t.Fatal("Copy returned the original transport")
+	}
+
+	copied.Options().Route = replacementRoute
+	if original.Options().Route != originalRoute {
+		t.Fatal("mutating copied transport changed original route")
+	}
+	if copied.Options().Route != replacementRoute {
+		t.Fatal("copied transport did not retain its independent route")
+	}
+}

go-gost/x/config/parsing/chain/parse.go

@@ -35,16 +35,18 @@ func ParseChain(cfg *config.ChainConfig, log logger.Logger) (chain.Chainer, erro
 	for _, ch := range cfg.Hops {
 		var hop hop.Hop
 		var err error
+		owned := false
 
 		if ch.Nodes != nil || ch.Plugin != nil {
 			if hop, err = hop_parser.ParseHop(ch, log); err != nil {
 				return nil, err
 			}
+			owned = true
 		} else {
 			hop = registry.HopRegistry().Get(ch.Name)
 		}
 		if hop != nil {
-			c.AddHop(hop)
+			c.AddHop(hop, owned)
 		}
 	}
 

go-gost/x/dialer/kcp/conn.go

@@ -19,20 +19,23 @@ func (session *muxSession) Accept() (net.Conn, error) {
 }
 
 func (session *muxSession) Close() error {
-	if session.session == nil {
+	if session == nil || session.session == nil {
 		return nil
 	}
 	return session.session.Close()
 }
 
 func (session *muxSession) IsClosed() bool {
-	if session.session == nil {
+	if session == nil || session.session == nil {
 		return true
 	}
 	return session.session.IsClosed()
 }
 
 func (session *muxSession) NumStreams() int {
+	if session == nil || session.session == nil {
+		return 0
+	}
 	return session.session.NumStreams()
 }
 

go-gost/x/dialer/kcp/dialer.go

@@ -11,6 +11,7 @@ import (
 	"github.com/go-gost/core/logger"
 	md "github.com/go-gost/core/metadata"
 	kcp_util "github.com/go-gost/x/internal/util/kcp"
+	"github.com/go-gost/x/internal/util/sessionretire"
 	mdutil "github.com/go-gost/x/metadata/util"
 	"github.com/go-gost/x/registry"
 	"github.com/xtaci/kcp-go/v5"
@@ -25,6 +26,7 @@ func init() {
 type kcpDialer struct {
 	sessions     map[string]*muxSession
 	sessionMutex sync.Mutex
+	retired      bool
 	logger       logger.Logger
 	md           metadata
 	options      dialer.Options
@@ -64,6 +66,9 @@ func (d *kcpDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialOp
 
 	d.sessionMutex.Lock()
 	defer d.sessionMutex.Unlock()
+	if d.retired {
+		return nil, net.ErrClosed
+	}
 
 	session, ok := d.sessions[addr]
 	if session != nil && session.IsClosed() {
@@ -171,3 +176,36 @@ func (d *kcpDialer) initSession(ctx context.Context, addr net.Addr, conn net.Pac
 func (d *kcpDialer) Multiplex() bool {
 	return true
 }
+
+// Retire drains existing streams and closes their backing sessions once idle.
+func (d *kcpDialer) Retire() {
+	for _, session := range d.detachSessions() {
+		sessionretire.Gracefully(session)
+	}
+}
+
+// Close immediately releases all cached multiplex sessions.
+func (d *kcpDialer) Close() error {
+	var errs []error
+	for _, session := range d.detachSessions() {
+		errs = append(errs, session.Close())
+	}
+	return errors.Join(errs...)
+}
+
+func (d *kcpDialer) detachSessions() []*muxSession {
+	if d == nil {
+		return nil
+	}
+	d.sessionMutex.Lock()
+	d.retired = true
+	sessions := make([]*muxSession, 0, len(d.sessions))
+	for _, session := range d.sessions {
+		if session != nil {
+			sessions = append(sessions, session)
+		}
+	}
+	d.sessions = make(map[string]*muxSession)
+	d.sessionMutex.Unlock()
+	return sessions
+}

go-gost/x/dialer/kcp/dialer_test.go

@@ -0,0 +1,17 @@
+package kcp
+
+import (
+	"context"
+	"errors"
+	"net"
+	"testing"
+)
+
+func TestRetiredDialerRejectsNewConnections(t *testing.T) {
+	dialer := NewDialer().(*kcpDialer)
+	dialer.Retire()
+
+	if _, err := dialer.Dial(context.Background(), "127.0.0.1:1"); !errors.Is(err, net.ErrClosed) {
+		t.Fatalf("Dial error = %v, want net.ErrClosed", err)
+	}
+}

go-gost/x/dialer/mtcp/conn.go

@@ -20,13 +20,24 @@ func (session *muxSession) Accept() (net.Conn, error) {
 }
 
 func (session *muxSession) Close() error {
+	if session == nil {
+		return nil
+	}
 	if session.session == nil {
+		if session.conn != nil {
+			conn := session.conn
+			session.conn = nil
+			return conn.Close()
+		}
 		return nil
 	}
 	return session.session.Close()
 }
 
 func (session *muxSession) IsClosed() bool {
+	if session == nil {
+		return true
+	}
 	if session.session == nil {
 		return true
 	}
@@ -34,5 +45,8 @@ func (session *muxSession) IsClosed() bool {
 }
 
 func (session *muxSession) NumStreams() int {
+	if session == nil || session.session == nil {
+		return 0
+	}
 	return session.session.NumStreams()
 }

go-gost/x/dialer/mtcp/dialer.go

@@ -11,6 +11,7 @@ import (
 	"github.com/go-gost/core/logger"
 	md "github.com/go-gost/core/metadata"
 	"github.com/go-gost/x/internal/util/mux"
+	"github.com/go-gost/x/internal/util/sessionretire"
 	"github.com/go-gost/x/registry"
 )
 
@@ -21,6 +22,7 @@ func init() {
 type mtcpDialer struct {
 	sessions     map[string]*muxSession
 	sessionMutex sync.Mutex
+	retired      bool
 	logger       logger.Logger
 	md           metadata
 	options      dialer.Options
@@ -55,6 +57,9 @@ func (d *mtcpDialer) Multiplex() bool {
 func (d *mtcpDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialOption) (conn net.Conn, err error) {
 	d.sessionMutex.Lock()
 	defer d.sessionMutex.Unlock()
+	if d.retired {
+		return nil, net.ErrClosed
+	}
 
 	session, ok := d.sessions[addr]
 	if session != nil && session.IsClosed() {
@@ -88,6 +93,10 @@ func (d *mtcpDialer) Handshake(ctx context.Context, conn net.Conn, options ...di
 
 	d.sessionMutex.Lock()
 	defer d.sessionMutex.Unlock()
+	if d.retired {
+		conn.Close()
+		return nil, net.ErrClosed
+	}
 
 	if d.md.handshakeTimeout > 0 {
 		conn.SetDeadline(time.Now().Add(d.md.handshakeTimeout))
@@ -129,3 +138,34 @@ func (d *mtcpDialer) initSession(ctx context.Context, conn net.Conn) (*muxSessio
 	}
 	return &muxSession{conn: conn, session: session}, nil
 }
+
+func (d *mtcpDialer) Retire() {
+	for _, session := range d.detachSessions() {
+		sessionretire.Gracefully(session)
+	}
+}
+
+func (d *mtcpDialer) Close() error {
+	var errs []error
+	for _, session := range d.detachSessions() {
+		errs = append(errs, session.Close())
+	}
+	return errors.Join(errs...)
+}
+
+func (d *mtcpDialer) detachSessions() []*muxSession {
+	if d == nil {
+		return nil
+	}
+	d.sessionMutex.Lock()
+	d.retired = true
+	sessions := make([]*muxSession, 0, len(d.sessions))
+	for _, session := range d.sessions {
+		if session != nil {
+			sessions = append(sessions, session)
+		}
+	}
+	d.sessions = make(map[string]*muxSession)
+	d.sessionMutex.Unlock()
+	return sessions
+}

go-gost/x/dialer/mtcp/dialer_test.go

@@ -0,0 +1,30 @@
+package mtcp
+
+import (
+	"context"
+	"errors"
+	"net"
+	"testing"
+)
+
+func TestRetiredDialerRejectsNewConnections(t *testing.T) {
+	dialer := NewDialer().(*mtcpDialer)
+	dialer.Retire()
+
+	if _, err := dialer.Dial(context.Background(), "127.0.0.1:1"); !errors.Is(err, net.ErrClosed) {
+		t.Fatalf("Dial error = %v, want net.ErrClosed", err)
+	}
+}
+
+func TestSessionCloseReleasesPreHandshakeConnection(t *testing.T) {
+	conn, peer := net.Pipe()
+	defer peer.Close()
+	session := &muxSession{conn: conn}
+
+	if err := session.Close(); err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	if !session.IsClosed() {
+		t.Fatal("pre-handshake session still reports open after Close")
+	}
+}

go-gost/x/dialer/mtls/conn.go

@@ -20,13 +20,24 @@ func (session *muxSession) Accept() (net.Conn, error) {
 }
 
 func (session *muxSession) Close() error {
+	if session == nil {
+		return nil
+	}
 	if session.session == nil {
+		if session.conn != nil {
+			conn := session.conn
+			session.conn = nil
+			return conn.Close()
+		}
 		return nil
 	}
 	return session.session.Close()
 }
 
 func (session *muxSession) IsClosed() bool {
+	if session == nil {
+		return true
+	}
 	if session.session == nil {
 		return true
 	}
@@ -34,5 +45,8 @@ func (session *muxSession) IsClosed() bool {
 }
 
 func (session *muxSession) NumStreams() int {
+	if session == nil || session.session == nil {
+		return 0
+	}
 	return session.session.NumStreams()
 }

go-gost/x/dialer/mtls/dialer.go

@@ -12,6 +12,7 @@ import (
 	"github.com/go-gost/core/logger"
 	md "github.com/go-gost/core/metadata"
 	"github.com/go-gost/x/internal/util/mux"
+	"github.com/go-gost/x/internal/util/sessionretire"
 	"github.com/go-gost/x/registry"
 )
 
@@ -22,6 +23,7 @@ func init() {
 type mtlsDialer struct {
 	sessions     map[string]*muxSession
 	sessionMutex sync.Mutex
+	retired      bool
 	logger       logger.Logger
 	md           metadata
 	options      dialer.Options
@@ -56,6 +58,9 @@ func (d *mtlsDialer) Multiplex() bool {
 func (d *mtlsDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialOption) (conn net.Conn, err error) {
 	d.sessionMutex.Lock()
 	defer d.sessionMutex.Unlock()
+	if d.retired {
+		return nil, net.ErrClosed
+	}
 
 	session, ok := d.sessions[addr]
 	if session != nil && session.IsClosed() {
@@ -89,6 +94,10 @@ func (d *mtlsDialer) Handshake(ctx context.Context, conn net.Conn, options ...di
 
 	d.sessionMutex.Lock()
 	defer d.sessionMutex.Unlock()
+	if d.retired {
+		conn.Close()
+		return nil, net.ErrClosed
+	}
 
 	if d.md.handshakeTimeout > 0 {
 		conn.SetDeadline(time.Now().Add(d.md.handshakeTimeout))
@@ -136,3 +145,34 @@ func (d *mtlsDialer) initSession(ctx context.Context, conn net.Conn) (*muxSessio
 	}
 	return &muxSession{conn: conn, session: session}, nil
 }
+
+func (d *mtlsDialer) Retire() {
+	for _, session := range d.detachSessions() {
+		sessionretire.Gracefully(session)
+	}
+}
+
+func (d *mtlsDialer) Close() error {
+	var errs []error
+	for _, session := range d.detachSessions() {
+		errs = append(errs, session.Close())
+	}
+	return errors.Join(errs...)
+}
+
+func (d *mtlsDialer) detachSessions() []*muxSession {
+	if d == nil {
+		return nil
+	}
+	d.sessionMutex.Lock()
+	d.retired = true
+	sessions := make([]*muxSession, 0, len(d.sessions))
+	for _, session := range d.sessions {
+		if session != nil {
+			sessions = append(sessions, session)
+		}
+	}
+	d.sessions = make(map[string]*muxSession)
+	d.sessionMutex.Unlock()
+	return sessions
+}

go-gost/x/dialer/mtls/dialer_test.go

@@ -0,0 +1,30 @@
+package mtls
+
+import (
+	"context"
+	"errors"
+	"net"
+	"testing"
+)
+
+func TestRetiredDialerRejectsNewConnections(t *testing.T) {
+	dialer := NewDialer().(*mtlsDialer)
+	dialer.Retire()
+
+	if _, err := dialer.Dial(context.Background(), "127.0.0.1:1"); !errors.Is(err, net.ErrClosed) {
+		t.Fatalf("Dial error = %v, want net.ErrClosed", err)
+	}
+}
+
+func TestSessionCloseReleasesPreHandshakeConnection(t *testing.T) {
+	conn, peer := net.Pipe()
+	defer peer.Close()
+	session := &muxSession{conn: conn}
+
+	if err := session.Close(); err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	if !session.IsClosed() {
+		t.Fatal("pre-handshake session still reports open after Close")
+	}
+}

go-gost/x/dialer/mws/conn.go

@@ -20,13 +20,24 @@ func (session *muxSession) Accept() (net.Conn, error) {
 }
 
 func (session *muxSession) Close() error {
+	if session == nil {
+		return nil
+	}
 	if session.session == nil {
+		if session.conn != nil {
+			conn := session.conn
+			session.conn = nil
+			return conn.Close()
+		}
 		return nil
 	}
 	return session.session.Close()
 }
 
 func (session *muxSession) IsClosed() bool {
+	if session == nil {
+		return true
+	}
 	if session.session == nil {
 		return true
 	}
@@ -34,5 +45,8 @@ func (session *muxSession) IsClosed() bool {
 }
 
 func (session *muxSession) NumStreams() int {
+	if session == nil || session.session == nil {
+		return 0
+	}
 	return session.session.NumStreams()
 }

go-gost/x/dialer/mws/dialer.go

@@ -12,6 +12,7 @@ import (
 	"github.com/go-gost/core/logger"
 	md "github.com/go-gost/core/metadata"
 	"github.com/go-gost/x/internal/util/mux"
+	"github.com/go-gost/x/internal/util/sessionretire"
 	ws_util "github.com/go-gost/x/internal/util/ws"
 	"github.com/go-gost/x/registry"
 	"github.com/gorilla/websocket"
@@ -25,6 +26,7 @@ func init() {
 type mwsDialer struct {
 	sessions     map[string]*muxSession
 	sessionMutex sync.Mutex
+	retired      bool
 	tlsEnabled   bool
 	md           metadata
 	options      dialer.Options
@@ -70,6 +72,9 @@ func (d *mwsDialer) Multiplex() bool {
 func (d *mwsDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialOption) (conn net.Conn, err error) {
 	d.sessionMutex.Lock()
 	defer d.sessionMutex.Unlock()
+	if d.retired {
+		return nil, net.ErrClosed
+	}
 
 	session, ok := d.sessions[addr]
 	if session != nil && session.IsClosed() {
@@ -108,6 +113,10 @@ func (d *mwsDialer) Handshake(ctx context.Context, conn net.Conn, options ...dia
 
 	d.sessionMutex.Lock()
 	defer d.sessionMutex.Unlock()
+	if d.retired {
+		conn.Close()
+		return nil, net.ErrClosed
+	}
 
 	session, ok := d.sessions[opts.Addr]
 	if session != nil && session.conn != conn {
@@ -208,3 +217,34 @@ func (d *mwsDialer) keepAlive(conn ws_util.WebsocketConn) {
 		conn.SetWriteDeadline(time.Time{})
 	}
 }
+
+func (d *mwsDialer) Retire() {
+	for _, session := range d.detachSessions() {
+		sessionretire.Gracefully(session)
+	}
+}
+
+func (d *mwsDialer) Close() error {
+	var errs []error
+	for _, session := range d.detachSessions() {
+		errs = append(errs, session.Close())
+	}
+	return errors.Join(errs...)
+}
+
+func (d *mwsDialer) detachSessions() []*muxSession {
+	if d == nil {
+		return nil
+	}
+	d.sessionMutex.Lock()
+	d.retired = true
+	sessions := make([]*muxSession, 0, len(d.sessions))
+	for _, session := range d.sessions {
+		if session != nil {
+			sessions = append(sessions, session)
+		}
+	}
+	d.sessions = make(map[string]*muxSession)
+	d.sessionMutex.Unlock()
+	return sessions
+}

go-gost/x/dialer/mws/dialer_test.go

@@ -0,0 +1,30 @@
+package mws
+
+import (
+	"context"
+	"errors"
+	"net"
+	"testing"
+)
+
+func TestRetiredDialerRejectsNewConnections(t *testing.T) {
+	dialer := NewDialer().(*mwsDialer)
+	dialer.Retire()
+
+	if _, err := dialer.Dial(context.Background(), "127.0.0.1:1"); !errors.Is(err, net.ErrClosed) {
+		t.Fatalf("Dial error = %v, want net.ErrClosed", err)
+	}
+}
+
+func TestSessionCloseReleasesPreHandshakeConnection(t *testing.T) {
+	conn, peer := net.Pipe()
+	defer peer.Close()
+	session := &muxSession{conn: conn}
+
+	if err := session.Close(); err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	if !session.IsClosed() {
+		t.Fatal("pre-handshake session still reports open after Close")
+	}
+}

go-gost/x/hop/hop.go

@@ -3,6 +3,7 @@ package hop
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"io"
 	"net"
 	"sort"
@@ -92,6 +93,7 @@ type chainHop struct {
 	nodes      []*chain.Node
 	mu         sync.RWMutex
 	cancelFunc context.CancelFunc
+	stopOnce   sync.Once
 	options    options
 }
 
@@ -383,13 +385,52 @@ func (p *chainHop) parseNode(r io.Reader) ([]*chain.Node, error) {
 	return nodes, nil
 }
 
-func (p *chainHop) Close() error {
-	p.cancelFunc()
-	if p.options.fileLoader != nil {
-		p.options.fileLoader.Close()
+func (p *chainHop) stopReload() {
+	if p == nil {
+		return
 	}
-	if p.options.redisLoader != nil {
-		p.options.redisLoader.Close()
-	}
-	return nil
+	p.stopOnce.Do(func() {
+		p.cancelFunc()
+		if p.options.fileLoader != nil {
+			p.options.fileLoader.Close()
+		}
+		if p.options.redisLoader != nil {
+			p.options.redisLoader.Close()
+		}
+		if p.options.httpLoader != nil {
+			p.options.httpLoader.Close()
+		}
+	})
+}
+
+func (p *chainHop) Retire() {
+	if p == nil {
+		return
+	}
+	p.stopReload()
+	for _, node := range p.Nodes() {
+		if node == nil || node.Options().Transport == nil {
+			continue
+		}
+		if retirer, ok := node.Options().Transport.(interface{ Retire() }); ok {
+			retirer.Retire()
+		}
+	}
+}
+
+func (p *chainHop) Close() error {
+	if p == nil {
+		return nil
+	}
+	p.stopReload()
+	var errs []error
+	for _, node := range p.Nodes() {
+		if node == nil || node.Options().Transport == nil {
+			continue
+		}
+		if closer, ok := node.Options().Transport.(io.Closer); ok {
+			errs = append(errs, closer.Close())
+		}
+	}
+	return errors.Join(errs...)
 }

go-gost/x/internal/util/sessionretire/sessionretire.go

@@ -0,0 +1,58 @@
+package sessionretire
+
+import "time"
+
+const (
+	defaultIdleGrace  = time.Second
+	defaultPollPeriod = 100 * time.Millisecond
+)
+
+// Session is the lifecycle surface shared by the multiplexed dialers.
+type Session interface {
+	Close() error
+	IsClosed() bool
+	NumStreams() int
+}
+
+// Gracefully closes a retired session after all existing streams have drained.
+// A short idle grace covers the Dial/Handshake hand-off used by several dialers.
+func Gracefully(session Session) {
+	if session == nil {
+		return
+	}
+	go waitUntilIdle(session, defaultIdleGrace, defaultPollPeriod)
+}
+
+func waitUntilIdle(session Session, idleGrace, pollPeriod time.Duration) {
+	if session == nil {
+		return
+	}
+	if idleGrace <= 0 {
+		idleGrace = defaultIdleGrace
+	}
+	if pollPeriod <= 0 {
+		pollPeriod = defaultPollPeriod
+	}
+
+	ticker := time.NewTicker(pollPeriod)
+	defer ticker.Stop()
+
+	var idleSince time.Time
+	for {
+		if session.IsClosed() {
+			_ = session.Close()
+			return
+		}
+		if session.NumStreams() == 0 {
+			if idleSince.IsZero() {
+				idleSince = time.Now()
+			} else if time.Since(idleSince) >= idleGrace {
+				_ = session.Close()
+				return
+			}
+		} else {
+			idleSince = time.Time{}
+		}
+		<-ticker.C
+	}
+}

go-gost/x/internal/util/sessionretire/sessionretire_test.go

@@ -0,0 +1,59 @@
+package sessionretire
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+type testSession struct {
+	mu      sync.Mutex
+	streams int
+	closed  bool
+}
+
+func (s *testSession) Close() error {
+	s.mu.Lock()
+	s.closed = true
+	s.mu.Unlock()
+	return nil
+}
+
+func (s *testSession) IsClosed() bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.closed
+}
+
+func (s *testSession) NumStreams() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.streams
+}
+
+func TestWaitUntilIdlePreservesActiveStreams(t *testing.T) {
+	session := &testSession{streams: 1}
+	done := make(chan struct{})
+	go func() {
+		waitUntilIdle(session, 20*time.Millisecond, time.Millisecond)
+		close(done)
+	}()
+
+	time.Sleep(30 * time.Millisecond)
+	if session.IsClosed() {
+		t.Fatal("active session was closed")
+	}
+
+	session.mu.Lock()
+	session.streams = 0
+	session.mu.Unlock()
+
+	select {
+	case <-done:
+	case <-time.After(250 * time.Millisecond):
+		t.Fatal("idle session was not closed")
+	}
+	if !session.IsClosed() {
+		t.Fatal("retired session did not close after becoming idle")
+	}
+}

go-gost/x/registry/chain.go

@@ -28,7 +28,13 @@ func (r *chainRegistry) Register(name string, v chain.Chainer) error {
 }
 
 func (r *chainRegistry) replace(name string, v chain.Chainer) {
-	r.m.Store(name, v)
+	old, loaded := r.m.Swap(name, v)
+	if !loaded {
+		return
+	}
+	if retirer, ok := old.(interface{ Retire() }); ok {
+		retirer.Retire()
+	}
 }
 
 func (r *chainRegistry) Get(name string) chain.Chainer {

go-gost/x/registry/chain_test.go

@@ -16,6 +16,15 @@ func (c testChainer) Route(context.Context, string, string, ...chain.RouteOption
 	return c.route
 }
 
+type retiringTestChainer struct {
+	testChainer
+	retired bool
+}
+
+func (c *retiringTestChainer) Retire() {
+	c.retired = true
+}
+
 type testRoute struct {
 	nodes []*chain.Node
 }
@@ -49,3 +58,20 @@ func TestReplaceChainOverwritesExistingRegistration(t *testing.T) {
 		t.Fatalf("expected replacement chain route, got %#v", route)
 	}
 }
+
+func TestReplaceChainRetiresPreviousRegistration(t *testing.T) {
+	name := "replace_chain_retire_tdd"
+	ChainRegistry().Unregister(name)
+	defer ChainRegistry().Unregister(name)
+
+	old := &retiringTestChainer{}
+	if err := ChainRegistry().Register(name, old); err != nil {
+		t.Fatalf("register old chain: %v", err)
+	}
+	if err := ReplaceChain(name, testChainer{}); err != nil {
+		t.Fatalf("replace chain: %v", err)
+	}
+	if !old.retired {
+		t.Fatal("previous chain was not retired")
+	}
+}

vite-frontend/src/pages/node/tunnel-monitor-view.tsx

@@ -492,21 +492,212 @@ const parseTunnelQualityChainDetails = (
   return {};
 };
 
-const candidateRoleLabel = (role: string) => {
-  switch (role) {
-    case "entry":
-      return "入口";
-    case "middle":
-      return "中转";
-    case "exit":
-      return "出口";
-    case "target":
-      return "测试目标";
-    default:
-      return role;
-  }
+type TunnelTopologyHop = TunnelQualityHopApiItem & {
+  errorMessage?: string;
 };
 
+interface TunnelTopologyPath {
+  key: string;
+  hops: TunnelTopologyHop[];
+  alternativeNodeIndex?: number;
+}
+
+const tunnelTopologyHopKey = (fromNodeId: number, toNodeId: number) =>
+  `${fromNodeId}:${toNodeId}`;
+
+const buildTunnelTopologyPaths = (
+  details: TunnelQualityChainDetailsApiItem,
+): TunnelTopologyPath[] => {
+  const primaryHops = details.primaryPath ?? [];
+  const candidates = details.candidateHops ?? [];
+
+  if (primaryHops.length === 0) {
+    const publicCandidates = candidates.filter(
+      (candidate) => candidate.toRole === "target",
+    );
+    const selected = publicCandidates.find((candidate) => candidate.selected);
+    const paths: TunnelTopologyPath[] = [];
+
+    if (selected) {
+      paths.push({ key: "primary-public", hops: [selected] });
+    }
+    for (const candidate of publicCandidates) {
+      if (candidate.selected) continue;
+      paths.push({
+        key: `alternative-public-${candidate.fromNodeId}`,
+        hops: [candidate],
+        alternativeNodeIndex: 0,
+      });
+    }
+
+    return paths;
+  }
+
+  const primaryNodeIds = [
+    primaryHops[0].fromNodeId,
+    ...primaryHops.map((hop) => hop.toNodeId),
+  ];
+  const internalCandidates = candidates.filter(
+    (candidate) => candidate.toRole !== "target",
+  );
+  const candidateHopMap = new Map<string, TunnelQualityCandidateHopApiItem>();
+  const alternativeNodes = new Map<
+    string,
+    { column: number; nodeId: number }
+  >();
+
+  for (const candidate of internalCandidates) {
+    candidateHopMap.set(
+      tunnelTopologyHopKey(candidate.fromNodeId, candidate.toNodeId),
+      candidate,
+    );
+
+    const sourceColumn = candidate.hopIndex;
+    const targetColumn = candidate.hopIndex + 1;
+
+    if (
+      sourceColumn >= 0 &&
+      sourceColumn < primaryNodeIds.length &&
+      candidate.fromNodeId !== primaryNodeIds[sourceColumn]
+    ) {
+      alternativeNodes.set(`${sourceColumn}:${candidate.fromNodeId}`, {
+        column: sourceColumn,
+        nodeId: candidate.fromNodeId,
+      });
+    }
+    if (
+      targetColumn >= 0 &&
+      targetColumn < primaryNodeIds.length &&
+      candidate.toNodeId !== primaryNodeIds[targetColumn]
+    ) {
+      alternativeNodes.set(`${targetColumn}:${candidate.toNodeId}`, {
+        column: targetColumn,
+        nodeId: candidate.toNodeId,
+      });
+    }
+  }
+
+  const paths: TunnelTopologyPath[] = [{ key: "primary", hops: primaryHops }];
+
+  for (const alternative of alternativeNodes.values()) {
+    const nodeIds = [...primaryNodeIds];
+
+    nodeIds[alternative.column] = alternative.nodeId;
+    const hops: TunnelTopologyHop[] = [];
+
+    for (let index = 0; index < nodeIds.length - 1; index += 1) {
+      const fromNodeId = nodeIds[index];
+      const toNodeId = nodeIds[index + 1];
+      const usesPrimaryEdge =
+        fromNodeId === primaryNodeIds[index] &&
+        toNodeId === primaryNodeIds[index + 1];
+      const hop = usesPrimaryEdge
+        ? primaryHops[index]
+        : candidateHopMap.get(tunnelTopologyHopKey(fromNodeId, toNodeId));
+
+      if (!hop) break;
+      hops.push(hop);
+    }
+
+    if (hops.length === primaryHops.length) {
+      paths.push({
+        key: `alternative-${alternative.column}-${alternative.nodeId}`,
+        hops,
+        alternativeNodeIndex: alternative.column,
+      });
+    }
+  }
+
+  return paths;
+};
+
+function TunnelTopologyPathRow({ path }: { path: TunnelTopologyPath }) {
+  return (
+    <div className="flex min-w-max items-center py-2">
+      {path.hops.map((hop, index) => {
+        const hasError =
+          Boolean(hop.errorMessage) || hop.latency < 0 || hop.loss > 0;
+        const colorClass =
+          hop.latency < 0 || hop.errorMessage
+            ? "text-danger"
+            : hop.loss > 0
+              ? "text-warning"
+              : "text-success";
+        const borderColor = hasError ? "border-danger" : "";
+
+        return (
+          <React.Fragment
+            key={`${path.key}-${hop.fromNodeId}-${hop.toNodeId}-${index}`}
+          >
+            {index === 0 ? (
+              <TopologyNodeChip
+                isAlternative={path.alternativeNodeIndex === 0}
+                name={hop.fromNodeName}
+              />
+            ) : null}
+            <div
+              className="relative mx-1 flex min-w-[70px] shrink-0 flex-col items-center justify-center"
+              title={hop.errorMessage}
+            >
+              <span
+                className={`mb-1 text-[10px] font-mono leading-none ${colorClass}`}
+              >
+                {hop.latency >= 0 && !hop.errorMessage
+                  ? `${hop.latency.toFixed(0)}ms`
+                  : "超时"}
+              </span>
+              <div
+                className={`relative flex h-[2px] w-full items-center justify-end bg-default-200 ${hop.latency < 0 || hop.errorMessage ? "!bg-danger" : ""}`}
+              >
+                <ArrowRight
+                  className={`absolute -right-2 z-10 h-3.5 w-3.5 rounded-full bg-background p-[1px] ${colorClass}`}
+                />
+              </div>
+              <span
+                className={`mt-1.5 text-[10px] font-mono leading-none ${hop.errorMessage || hop.loss > 0 ? "text-warning" : "text-default-400"}`}
+              >
+                {hop.errorMessage ? "探测失败" : `${hop.loss.toFixed(0)}% 丢包`}
+              </span>
+            </div>
+            <TopologyNodeChip
+              borderColor={borderColor}
+              isAlternative={path.alternativeNodeIndex === index + 1}
+              name={hop.toNodeName}
+            />
+          </React.Fragment>
+        );
+      })}
+    </div>
+  );
+}
+
+function TopologyNodeChip({
+  name,
+  isAlternative = false,
+  borderColor = "",
+}: {
+  name: string;
+  isAlternative?: boolean;
+  borderColor?: string;
+}) {
+  return (
+    <Chip
+      className={`shrink-0 font-mono shadow-sm ${borderColor}`}
+      size="sm"
+      variant="flat"
+    >
+      <span className="flex items-center gap-1.5">
+        <span>{name}</span>
+        {isAlternative ? (
+          <span className="rounded-full bg-warning/20 px-1.5 py-0.5 text-[9px] font-semibold leading-none text-warning">
+            备选
+          </span>
+        ) : null}
+      </span>
+    </Chip>
+  );
+}
+
 const ForwardingChainTopology = React.memo(function ForwardingChainTopology({
   hopsStr,
 }: {
@@ -516,13 +707,12 @@ const ForwardingChainTopology = React.memo(function ForwardingChainTopology({
     () => parseTunnelQualityChainDetails(hopsStr),
     [hopsStr],
   );
-  const primaryHops = details.primaryPath ?? [];
-  const alternativeHops = useMemo(
-    () => (details.candidateHops ?? []).filter((hop) => !hop.selected),
-    [details.candidateHops],
+  const topologyPaths = useMemo(
+    () => buildTunnelTopologyPaths(details),
+    [details],
   );
 
-  if (primaryHops.length === 0 && alternativeHops.length === 0) return null;
+  if (topologyPaths.length === 0) return null;
 
   return (
     <Card className="border border-divider/60 shadow-sm transition-shadow bg-gradient-to-br from-background to-default-50/50 mt-4">
@@ -533,133 +723,25 @@ const ForwardingChainTopology = React.memo(function ForwardingChainTopology({
         </h3>
       </CardHeader>
       <CardBody className="py-2 px-4 pb-4">
-        {primaryHops.length > 0 ? (
-          <div className="flex items-center overflow-x-auto pb-2 py-2">
-            {primaryHops.map((hop, index) => {
-              const hasError = hop.latency < 0 || hop.loss > 0;
-              const colorClass =
-                hop.latency < 0
-                  ? "text-danger"
-                  : hop.loss > 0
-                    ? "text-warning"
-                    : "text-success";
-              const borderColor = hasError ? "border-danger" : "";
-
-              return (
-                <React.Fragment
-                  key={`${hop.fromNodeId}-${hop.toNodeId}-${index}`}
-                >
-                  {index === 0 ? (
-                    <Chip
-                      className="shrink-0 font-mono shadow-sm"
-                      size="sm"
-                      variant="flat"
-                    >
-                      {hop.fromNodeName}
-                    </Chip>
-                  ) : null}
-                  <div className="flex flex-col items-center justify-center min-w-[70px] mx-1 shrink-0 relative">
-                    <span
-                      className={`text-[10px] font-mono leading-none mb-1 ${colorClass}`}
-                    >
-                      {hop.latency >= 0
-                        ? `${hop.latency.toFixed(0)}ms`
-                        : "超时"}
-                    </span>
-                    <div
-                      className={`h-[2px] w-full relative flex items-center justify-end bg-default-200 ${hop.latency < 0 ? "!bg-danger" : ""}`}
-                    >
-                      <ArrowRight
-                        className={`w-3.5 h-3.5 absolute -right-2 ${colorClass} bg-background rounded-full p-[1px] z-10`}
-                      />
-                    </div>
-                    <span
-                      className={`text-[10px] font-mono leading-none mt-1.5 ${hop.loss > 0 ? "text-warning" : "text-default-400"}`}
-                    >
-                      {hop.loss.toFixed(0)}% 丢包
-                    </span>
-                  </div>
-                  <Chip
-                    className={`shrink-0 font-mono shadow-sm ${borderColor}`}
-                    size="sm"
-                    variant="flat"
-                  >
-                    {hop.toNodeName}
-                  </Chip>
-                </React.Fragment>
-              );
-            })}
-          </div>
-        ) : null}
-
-        {alternativeHops.length > 0 ? (
-          <div
-            className={`${primaryHops.length > 0 ? "mt-3 border-t border-divider/60 pt-3" : ""}`}
-          >
-            <div className="mb-2 flex items-center justify-between gap-2">
-              <span className="text-xs font-semibold text-default-600">
-                备选节点实时延迟
-              </span>
-              <span className="text-[10px] text-default-400">
-                {alternativeHops.length} 条候选链路
-              </span>
+        <div className="max-h-80 space-y-1 overflow-auto pb-1">
+          {topologyPaths.map((path, index) => (
+            <div
+              key={path.key}
+              className={
+                index === 0
+                  ? "overflow-x-auto"
+                  : "overflow-x-auto border-t border-dashed border-divider/60"
+              }
+            >
+              <TunnelTopologyPathRow path={path} />
             </div>
-            <div className="grid max-h-72 grid-cols-1 gap-2 overflow-y-auto pr-1 md:grid-cols-2">
-              {alternativeHops.map((hop) => (
-                <CandidateHopLatency
-                  key={`${hop.hopIndex}-${hop.fromNodeId}-${hop.toRole}-${hop.toNodeId || hop.toNodeName}`}
-                  hop={hop}
-                />
-              ))}
-            </div>
-          </div>
-        ) : null}
+          ))}
+        </div>
       </CardBody>
     </Card>
   );
 });
 
-function CandidateHopLatency({
-  hop,
-}: {
-  hop: TunnelQualityCandidateHopApiItem;
-}) {
-  const hasError = Boolean(hop.errorMessage) || hop.latency < 0;
-
-  return (
-    <div className="rounded-xl border border-divider/60 bg-default-50/50 px-3 py-2.5">
-      <div className="flex items-center gap-2 text-xs">
-        <span className="min-w-0 truncate font-medium text-foreground">
-          {hop.fromNodeName}
-        </span>
-        <ArrowRight className="h-3.5 w-3.5 shrink-0 text-default-400" />
-        <span className="min-w-0 truncate font-medium text-foreground">
-          {hop.toNodeName}
-        </span>
-        <span className="ml-auto shrink-0">
-          <LatencyDisplay value={hop.latency} />
-        </span>
-      </div>
-      <div className="mt-1.5 flex items-center gap-2 text-[10px] text-default-400">
-        <span>
-          {candidateRoleLabel(hop.fromRole)} → {candidateRoleLabel(hop.toRole)}
-        </span>
-        {hasError ? (
-          <span className="ml-auto truncate text-danger">
-            {hop.errorMessage || "探测失败"}
-          </span>
-        ) : (
-          <span
-            className={`ml-auto font-mono ${hop.loss > 0 ? "text-warning" : "text-default-500"}`}
-          >
-            {hop.loss.toFixed(0)}% 丢包
-          </span>
-        )}
-      </div>
-    </div>
-  );
-}
-
 export function TunnelMonitorView({
   viewMode = "grid",
 }: TunnelMonitorViewProps) {