refactor(handler/forward/remote): split handler into 6 focused files with 41 tests

Split the 339-line handler monolith and 1169-line test blob into 11 files
(5 source + 6 test) following the handler/forward/local/ pattern.

Source files: handler.go (core), forward.go (raw forwarding),
sniffing.go (SnifferBuilder + protocol dispatch), util.go (errors +
recorder + rate limit), metadata.go (config parsing).

Fixes: add sync.Mutex for hop access (race), use sentinel errors for
errors.Is compatibility, add nil-addr guard in checkRateLimit, reuse
SnifferBuilder via Build() instead of per-call construction.

handler/forward/remote/forward.go

@@ -0,0 +1,101 @@
+package remote
+
+import (
+	"bytes"
+	"context"
+	"net"
+	"time"
+
+	"github.com/go-gost/core/chain"
+	"github.com/go-gost/core/hop"
+	"github.com/go-gost/core/logger"
+	xctx "github.com/go-gost/x/ctx"
+	ictx "github.com/go-gost/x/internal/ctx"
+	xnet "github.com/go-gost/x/internal/net"
+	"github.com/go-gost/x/internal/net/proxyproto"
+	mdutil "github.com/go-gost/x/metadata/util"
+	xrecorder "github.com/go-gost/x/recorder"
+)
+
+// handleRawForwarding performs node selection, dials the target through the
+// router, and pipes the raw connection. It is used when sniffing is disabled
+// or the protocol was not HTTP/TLS.
+func (h *forwardHandler) handleRawForwarding(ctx context.Context, conn net.Conn, ro *xrecorder.HandlerRecorderObject, log logger.Logger, network, proto string) error {
+	target := h.selectTarget(ctx, proto)
+	if target == nil {
+		log.Error(errNodeNotAvailable)
+		return errNodeNotAvailable
+	}
+	addr := target.Addr
+	if opts := target.Options(); opts != nil {
+		switch opts.Network {
+		case "unix":
+			network = opts.Network
+		default:
+			if _, _, err := net.SplitHostPort(addr); err != nil {
+				addr += ":0"
+			}
+		}
+	}
+
+	ro.Network = network
+	ro.Host = addr
+
+	log = log.WithFields(map[string]any{
+		"node":    target.Name,
+		"dst":     addr,
+		"network": network,
+	})
+
+	log.Debugf("%s >> %s", conn.RemoteAddr(), addr)
+
+	var buf bytes.Buffer
+	cc, err := h.options.Router.Dial(ictx.ContextWithBuffer(ctx, &buf), network, addr)
+	ro.Route = buf.String()
+	if err != nil {
+		log.Error(err)
+		// TODO: the router itself may be failed due to the failed node in the router,
+		// the dead marker may be a wrong operation.
+		if marker := target.Marker(); marker != nil {
+			marker.Mark()
+		}
+		return err
+	}
+	if marker := target.Marker(); marker != nil {
+		marker.Reset()
+	}
+	defer cc.Close()
+
+	cc = proxyproto.WrapClientConn(
+		h.md.proxyProtocol,
+		xctx.SrcAddrFromContext(ctx),
+		xctx.DstAddrFromContext(ctx),
+		cc)
+
+	log = log.WithFields(map[string]any{"src": cc.LocalAddr().String(), "dst": cc.RemoteAddr().String()})
+	ro.SrcAddr = cc.LocalAddr().String()
+	ro.DstAddr = cc.RemoteAddr().String()
+
+	t := time.Now()
+	log.Infof("%s <-> %s", conn.RemoteAddr(), target.Addr)
+	if err := xnet.Pipe(ctx, conn, cc, xnet.WithReadTimeout(h.md.readTimeout)); err != nil {
+		log.Debugf("pipe: %v", err)
+	}
+	log.WithFields(map[string]any{
+		"duration": time.Since(t),
+	}).Infof("%s >-< %s", conn.RemoteAddr(), target.Addr)
+
+	return nil
+}
+
+// selectTarget picks a forwarding target, preferring the host from context
+// metadata when set, then falling back to hop selection.
+func (h *forwardHandler) selectTarget(ctx context.Context, proto string) *chain.Node {
+	if host := mdutil.GetString(ictx.MetadataFromContext(ctx), "host"); host != "" {
+		return &chain.Node{Addr: host}
+	}
+	if curHop := h.getHop(); curHop != nil {
+		return curHop.Select(ctx, hop.ProtocolSelectOption(proto))
+	}
+	return nil
+}

handler/forward/remote/forward_test.go

@@ -0,0 +1,233 @@
+package remote
+
+import (
+	"context"
+	"errors"
+	"net"
+	"testing"
+
+	"github.com/go-gost/core/chain"
+	"github.com/go-gost/core/hop"
+	ictx "github.com/go-gost/x/internal/ctx"
+	xmd "github.com/go-gost/x/metadata"
+	xrecorder "github.com/go-gost/x/recorder"
+)
+
+// ---------------------------------------------------------------------------
+// handleRawForwarding
+// ---------------------------------------------------------------------------
+
+func TestHandleRawForwarding_NilHop(t *testing.T) {
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return nil, errors.New("no route to host")
+		},
+	}))
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	err := h.handleRawForwarding(context.Background(), conn, ro, nopLog(), "tcp", "")
+	if err == nil {
+		t.Fatal("expected error when hop is nil")
+	}
+}
+
+func TestHandleRawForwarding_NodeUnavailable(t *testing.T) {
+	h := newInitdHandler()
+	h.Forward(&mockHop{
+		selectFn: func(ctx context.Context, opts ...hop.SelectOption) *chain.Node {
+			return nil
+		},
+	})
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	err := h.handleRawForwarding(context.Background(), conn, ro, nopLog(), "tcp", "")
+	if err == nil {
+		t.Fatal("expected error when node is nil")
+	}
+	if !errors.Is(err, errNodeNotAvailable) {
+		t.Errorf("expected errNodeNotAvailable, got %v", err)
+	}
+}
+
+func TestHandleRawForwarding_DialError(t *testing.T) {
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return nil, errors.New("dial failed")
+		},
+	}))
+	h.Forward(&mockHop{
+		selectFn: func(ctx context.Context, opts ...hop.SelectOption) *chain.Node {
+			return chain.NewNode("test-node", "127.0.0.1:9999")
+		},
+	})
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	err := h.handleRawForwarding(context.Background(), conn, ro, nopLog(), "tcp", "")
+	if err == nil {
+		t.Fatal("expected error when dial fails")
+	}
+	if ro.Host != "127.0.0.1:9999" {
+		t.Errorf("expected host 127.0.0.1:9999, got %s", ro.Host)
+	}
+}
+
+func TestHandleRawForwarding_Success(t *testing.T) {
+	server, client := net.Pipe()
+	defer server.Close()
+	defer client.Close()
+
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return server, nil
+		},
+	}))
+	h.Forward(&mockHop{
+		selectFn: func(ctx context.Context, opts ...hop.SelectOption) *chain.Node {
+			return &chain.Node{Addr: "10.0.0.1:80", Name: "upstream"}
+		},
+	})
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	err := h.handleRawForwarding(context.Background(), conn, ro, nopLog(), "tcp", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if ro.Host != "10.0.0.1:80" {
+		t.Errorf("expected host 10.0.0.1:80, got %s", ro.Host)
+	}
+	if ro.Network != "tcp" {
+		t.Errorf("expected network tcp, got %s", ro.Network)
+	}
+	if ro.SrcAddr == "" {
+		t.Error("expected SrcAddr to be set")
+	}
+	if ro.DstAddr == "" {
+		t.Error("expected DstAddr to be set")
+	}
+}
+
+func TestHandleRawForwarding_AddrWithoutPort(t *testing.T) {
+	server, client := net.Pipe()
+	defer server.Close()
+	defer client.Close()
+
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return server, nil
+		},
+	}))
+	h.Forward(&mockHop{
+		selectFn: func(ctx context.Context, opts ...hop.SelectOption) *chain.Node {
+			return &chain.Node{Addr: "10.0.0.1", Name: "noport"}
+		},
+	})
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	err := h.handleRawForwarding(context.Background(), conn, ro, nopLog(), "tcp", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if ro.Host != "10.0.0.1:0" {
+		t.Errorf("expected ':0' appended to addr, got %s", ro.Host)
+	}
+}
+
+func TestHandleRawForwarding_UnixSocket(t *testing.T) {
+	server, client := net.Pipe()
+	defer server.Close()
+	defer client.Close()
+
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return server, nil
+		},
+	}))
+	h.Forward(&mockHop{
+		selectFn: func(ctx context.Context, opts ...hop.SelectOption) *chain.Node {
+			return chain.NewNode("unix-node", "/tmp/unix.sock",
+				chain.NetworkNodeOption("unix"),
+			)
+		},
+	})
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	err := h.handleRawForwarding(context.Background(), conn, ro, nopLog(), "tcp", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if ro.Network != "unix" {
+		t.Errorf("expected network 'unix', got '%s'", ro.Network)
+	}
+}
+
+func TestHandleRawForwarding_MarkerReset(t *testing.T) {
+	server, client := net.Pipe()
+	defer server.Close()
+	defer client.Close()
+
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return server, nil
+		},
+	}))
+	h.Forward(&mockHop{
+		selectFn: func(ctx context.Context, opts ...hop.SelectOption) *chain.Node {
+			return chain.NewNode("target", "10.0.0.1:80")
+		},
+	})
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	err := h.handleRawForwarding(context.Background(), conn, ro, nopLog(), "tcp", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if ro.Host != "10.0.0.1:80" {
+		t.Errorf("expected host '10.0.0.1:80', got '%s'", ro.Host)
+	}
+}
+
+func TestHandleRawForwarding_ContextHost(t *testing.T) {
+	server, client := net.Pipe()
+	defer server.Close()
+	defer client.Close()
+
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return server, nil
+		},
+	}))
+	h.Forward(&mockHop{
+		selectFn: func(ctx context.Context, opts ...hop.SelectOption) *chain.Node {
+			return &chain.Node{Addr: "10.0.0.2:80"}
+		},
+	})
+	ctx := ictx.ContextWithMetadata(context.Background(), xmd.NewMetadata(map[string]any{
+		"host": "10.0.0.99:8080",
+	}))
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	err := h.handleRawForwarding(ctx, conn, ro, nopLog(), "tcp", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if ro.Host != "10.0.0.99:8080" {
+		t.Errorf("expected host from context, got '%s'", ro.Host)
+	}
+}

handler/forward/remote/handler.go

@@ -1,29 +1,81 @@
+// Package remote implements a reverse forwarding handler for connections
+// received from remote GOST nodes. It listens for "rtcp" and "rudp" protocols
+// and forwards the accepted connections to the configured hop.
+//
+// The handler is registered under the names "rtcp" and "rudp" via
+// NewHandler in init().
+//
+// # Connection processing flow
+//
+// Each inbound net.Conn is processed by Handle, which wraps the connection
+// with I/O stats, checks the rate limiter, and dispatches to one of two
+// forwarding paths:
+//
+//	Handle()
+//	  ├─ stats_wrapper.WrapConn (per-connection I/O counters)
+//	  ├─ newRecorderObject (session metadata: service, SID, addresses)
+//	  ├─ checkRateLimit (connection rate limiter, if configured)
+//	  ├─ Router nil check → errRouterNotAvailable
+//	  ├─ [sniffing enabled] sniffing.Sniff (peek buffer, detect protocol)
+//	  │     └─ handleSniffedProtocol()
+//	  │           ├─ sniffing.ProtoHTTP → SnifferBuilder.Build().HandleHTTP()
+//	  │           ├─ sniffing.ProtoTLS  → SnifferBuilder.Build().HandleTLS()
+//	  │           └─ default → fall through to raw forwarding
+//	  └─ [sniffing disabled / unrecognised] handleRawForwarding()
+//
+// # Protocol sniffing dispatch (handleSniffedProtocol)
+//
+// When sniffing is enabled and the initial bytes match HTTP or TLS, the
+// connection is delegated to the forwarder package for protocol-aware
+// handling:
+//
+//   - HTTP: parses the request, applies MITM if configured, forwards to
+//     the upstream, and records WebSocket frames when enabled.
+//   - TLS: parses the ClientHello to extract the server name, applies
+//     MITM or SNI-based routing through the hop, and records the TLS
+//     handshake.
+//
+// SnifferBuilder is populated once during Init and reused via Build()
+// to create per-connection forwarder.Sniffer instances.
+//
+// # Raw forwarding (handleRawForwarding)
+//
+// The default path for unrecognised traffic. It selects a target node
+// from context metadata or the hop, dials the upstream through the
+// router, wraps the connection with proxy protocol (HAProxy) when
+// enabled, and pipes data bidirectionally:
+//
+//  1. Node selection — context host metadata takes priority, then
+//     getHop().Select() with optional protocol hint.
+//  2. Router dial — Router.Dial() through the configured chain.
+//  3. Proxy protocol — proxyproto.WrapClientConn() prepends HAProxy
+//     header when metadata proxyProtocol is set.
+//  4. Bidirectional pipe — xnet.Pipe(ctx, conn, cc) with read timeout.
+//
+// # Hop management
+//
+// The handler implements handler.Forwarder. Forward() is called during
+// service startup (and on reload) to install or update the hop. The hop
+// is protected by a mutex because Forward() runs on the loader goroutine
+// while Handle() reads it from per-connection goroutines.
 package remote
 
 import (
 	"bufio"
-	"bytes"
 	"context"
-	"errors"
 	"net"
+	"sync"
 	"time"
 
-	"github.com/go-gost/core/chain"
 	"github.com/go-gost/core/handler"
 	"github.com/go-gost/core/hop"
-	"github.com/go-gost/core/logger"
 	md "github.com/go-gost/core/metadata"
 	"github.com/go-gost/core/observer/stats"
 	"github.com/go-gost/core/recorder"
-	xctx "github.com/go-gost/x/ctx"
-	ictx "github.com/go-gost/x/internal/ctx"
 	xnet "github.com/go-gost/x/internal/net"
-	"github.com/go-gost/x/internal/net/proxyproto"
-	"github.com/go-gost/x/internal/util/forwarder"
 	"github.com/go-gost/x/internal/util/sniffing"
 	tls_util "github.com/go-gost/x/internal/util/tls"
 	rate_limiter "github.com/go-gost/x/limiter/rate"
-	mdutil "github.com/go-gost/x/metadata/util"
 	xstats "github.com/go-gost/x/observer/stats"
 	stats_wrapper "github.com/go-gost/x/observer/stats/wrapper"
 	xrecorder "github.com/go-gost/x/recorder"
@@ -37,10 +89,12 @@ func init() {
 
 type forwardHandler struct {
 	hop      hop.Hop
+	hopMu    sync.Mutex
 	md       metadata
 	options  handler.Options
 	recorder recorder.RecorderObject
 	certPool tls_util.CertPool
+	sniffer  *SnifferBuilder
 }
 
 // NewHandler creates a remote forwarding handler with the given options.
@@ -72,12 +126,33 @@ func (h *forwardHandler) Init(md md.Metadata) (err error) {
 		h.certPool = tls_util.NewMemoryCertPool()
 	}
 
+	h.sniffer = &SnifferBuilder{
+		Websocket:           h.md.sniffingWebsocket,
+		WebsocketSampleRate: h.md.sniffingWebsocketSampleRate,
+		Recorder:            h.recorder.Recorder,
+		RecorderOptions:     h.recorder.Options,
+		Certificate:         h.md.certificate,
+		PrivateKey:          h.md.privateKey,
+		ALPN:                h.md.alpn,
+		CertPool:            h.certPool,
+		MitmBypass:          h.md.mitmBypass,
+		ReadTimeout:         h.md.readTimeout,
+	}
+
 	return
 }
 
 // Forward implements handler.Forwarder.
 func (h *forwardHandler) Forward(hop hop.Hop) {
+	h.hopMu.Lock()
 	h.hop = hop
+	h.hopMu.Unlock()
+}
+
+func (h *forwardHandler) getHop() hop.Hop {
+	h.hopMu.Lock()
+	defer h.hopMu.Unlock()
+	return h.hop
 }
 
 // Handle forwards the accepted connection to a node selected from the hop.
@@ -126,9 +201,8 @@ func (h *forwardHandler) Handle(ctx context.Context, conn net.Conn, opts ...hand
 	}
 
 	if h.options.Router == nil {
-		err := errors.New("router not available")
+		log.Error(errRouterNotAvailable)
-		log.Error(err)
+		return errRouterNotAvailable
-		return err
 	}
 
 	var proto string
@@ -157,182 +231,3 @@ func (h *forwardHandler) Handle(ctx context.Context, conn net.Conn, opts ...hand
 
 	return h.handleRawForwarding(ctx, conn, ro, log, network, proto)
 }
-
-// handleRawForwarding performs node selection, dials the target through the
-// router, and pipes the raw connection. It is used when sniffing is disabled
-// or the protocol was not HTTP/TLS.
-func (h *forwardHandler) handleRawForwarding(ctx context.Context, conn net.Conn, ro *xrecorder.HandlerRecorderObject, log logger.Logger, network, proto string) error {
-	target := h.selectTarget(ctx, proto)
-	if target == nil {
-		err := errors.New("node not available")
-		log.Error(err)
-		return err
-	}
-	addr := target.Addr
-	if opts := target.Options(); opts != nil {
-		switch opts.Network {
-		case "unix":
-			network = opts.Network
-		default:
-			if _, _, err := net.SplitHostPort(addr); err != nil {
-				addr += ":0"
-			}
-		}
-	}
-
-	ro.Network = network
-	ro.Host = addr
-
-	log = log.WithFields(map[string]any{
-		"node":    target.Name,
-		"dst":     addr,
-		"network": network,
-	})
-
-	log.Debugf("%s >> %s", conn.RemoteAddr(), addr)
-
-	var buf bytes.Buffer
-	cc, err := h.options.Router.Dial(ictx.ContextWithBuffer(ctx, &buf), network, addr)
-	ro.Route = buf.String()
-	if err != nil {
-		log.Error(err)
-		// TODO: the router itself may be failed due to the failed node in the router,
-		// the dead marker may be a wrong operation.
-		if marker := target.Marker(); marker != nil {
-			marker.Mark()
-		}
-		return err
-	}
-	if marker := target.Marker(); marker != nil {
-		marker.Reset()
-	}
-	defer cc.Close()
-
-	cc = proxyproto.WrapClientConn(
-		h.md.proxyProtocol,
-		xctx.SrcAddrFromContext(ctx),
-		xctx.DstAddrFromContext(ctx),
-		cc)
-
-	log = log.WithFields(map[string]any{"src": cc.LocalAddr().String(), "dst": cc.RemoteAddr().String()})
-	ro.SrcAddr = cc.LocalAddr().String()
-	ro.DstAddr = cc.RemoteAddr().String()
-
-	t := time.Now()
-	log.Infof("%s <-> %s", conn.RemoteAddr(), target.Addr)
-	if err := xnet.Pipe(ctx, conn, cc, xnet.WithReadTimeout(h.md.readTimeout)); err != nil {
-		log.Debugf("pipe: %v", err)
-	}
-	log.WithFields(map[string]any{
-		"duration": time.Since(t),
-	}).Infof("%s >-< %s", conn.RemoteAddr(), target.Addr)
-
-	return nil
-}
-
-// selectTarget picks a forwarding target, preferring the host from context
-// metadata when set, then falling back to hop selection.
-func (h *forwardHandler) selectTarget(ctx context.Context, proto string) *chain.Node {
-	if host := mdutil.GetString(ictx.MetadataFromContext(ctx), "host"); host != "" {
-		return &chain.Node{Addr: host}
-	}
-	if h.hop != nil {
-		return h.hop.Select(ctx, hop.ProtocolSelectOption(proto))
-	}
-	return nil
-}
-
-// newRecorderObject creates a HandlerRecorderObject populated with connection
-// metadata (service, addresses, network type, session ID, client address).
-func (h *forwardHandler) newRecorderObject(ctx context.Context, conn net.Conn, start time.Time) *xrecorder.HandlerRecorderObject {
-	ro := &xrecorder.HandlerRecorderObject{
-		Service:    h.options.Service,
-		RemoteAddr: conn.RemoteAddr().String(),
-		LocalAddr:  conn.LocalAddr().String(),
-		Network:    "tcp",
-		Time:       start,
-		SID:        xctx.SidFromContext(ctx).String(),
-	}
-	if srcAddr := xctx.SrcAddrFromContext(ctx); srcAddr != nil {
-		ro.ClientAddr = srcAddr.String()
-	}
-	if _, ok := conn.(net.PacketConn); ok {
-		ro.Network = "udp"
-	}
-	return ro
-}
-
-// sniffingDial creates a dial function for the sniffing branch that wraps
-// Router.Dial with route recording and proxy protocol encapsulation.
-func (h *forwardHandler) sniffingDial(ctx context.Context, network, address string, ro *xrecorder.HandlerRecorderObject) (net.Conn, error) {
-	var buf bytes.Buffer
-	cc, err := h.options.Router.Dial(ictx.ContextWithBuffer(ctx, &buf), "tcp", address)
-	ro.Route = buf.String()
-	return proxyproto.WrapClientConn(
-		h.md.proxyProtocol,
-		xctx.SrcAddrFromContext(ctx),
-		xctx.DstAddrFromContext(ctx),
-		cc), err
-}
-
-// buildSniffer creates a forwarder.Sniffer configured from handler metadata.
-func (h *forwardHandler) buildSniffer() *forwarder.Sniffer {
-	return &forwarder.Sniffer{
-		Websocket:           h.md.sniffingWebsocket,
-		WebsocketSampleRate: h.md.sniffingWebsocketSampleRate,
-		Recorder:            h.recorder.Recorder,
-		RecorderOptions:     h.recorder.Options,
-		Certificate:         h.md.certificate,
-		PrivateKey:          h.md.privateKey,
-		NegotiatedProtocol:  h.md.alpn,
-		CertPool:            h.certPool,
-		MitmBypass:          h.md.mitmBypass,
-		ReadTimeout:         h.md.readTimeout,
-	}
-}
-
-// handleSniffedProtocol dispatches a sniffed connection to the protocol-specific
-// sniffer (HandleHTTP or HandleTLS). It returns (true, err) when the protocol was
-// handled and (false, nil) when the caller should fall through to raw forwarding.
-func (h *forwardHandler) handleSniffedProtocol(ctx context.Context, conn net.Conn, ro *xrecorder.HandlerRecorderObject, log logger.Logger, proto string) (handled bool, err error) {
-	switch proto {
-	case sniffing.ProtoHTTP, sniffing.ProtoTLS:
-		dial := func(ctx context.Context, network, address string) (net.Conn, error) {
-			return h.sniffingDial(ctx, network, address, ro)
-		}
-		sniffer := h.buildSniffer()
-		if proto == sniffing.ProtoHTTP {
-			return true, sniffer.HandleHTTP(ctx, conn,
-				forwarder.WithService(h.options.Service),
-				forwarder.WithDial(dial),
-				forwarder.WithHop(h.hop),
-				forwarder.WithBypass(h.options.Bypass),
-				forwarder.WithHTTPKeepalive(h.md.httpKeepalive),
-				forwarder.WithRecorderObject(ro),
-				forwarder.WithLog(log),
-			)
-		}
-		return true, sniffer.HandleTLS(ctx, conn,
-			forwarder.WithService(h.options.Service),
-			forwarder.WithDial(dial),
-			forwarder.WithHop(h.hop),
-			forwarder.WithBypass(h.options.Bypass),
-			forwarder.WithRecorderObject(ro),
-			forwarder.WithLog(log),
-		)
-	default:
-		return false, nil
-	}
-}
-
-func (h *forwardHandler) checkRateLimit(addr net.Addr) bool {
-	if h.options.RateLimiter == nil {
-		return true
-	}
-	host, _, _ := net.SplitHostPort(addr.String())
-	if limiter := h.options.RateLimiter.Limiter(host); limiter != nil {
-		return limiter.Allow(1)
-	}
-
-	return true
-}

handler/forward/remote/helpers_test.go

@@ -0,0 +1,243 @@
+package remote
+
+import (
+	"bytes"
+	"context"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"errors"
+	"math/big"
+	"net"
+	"os"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/go-gost/core/chain"
+	"github.com/go-gost/core/handler"
+	"github.com/go-gost/core/hop"
+	"github.com/go-gost/core/limiter/rate"
+	"github.com/go-gost/core/logger"
+	"github.com/go-gost/core/recorder"
+	xlogger "github.com/go-gost/x/logger"
+	xmd "github.com/go-gost/x/metadata"
+)
+
+// ---------------------------------------------------------------------------
+// Mocks
+// ---------------------------------------------------------------------------
+
+// mockRouter implements chain.Router.
+type mockRouter struct {
+	opts   *chain.RouterOptions
+	dialFn func(ctx context.Context, network, address string) (net.Conn, error)
+}
+
+func (m *mockRouter) Options() *chain.RouterOptions { return m.opts }
+func (m *mockRouter) Dial(ctx context.Context, network, address string, opts ...chain.DialOption) (net.Conn, error) {
+	if m.dialFn != nil {
+		return m.dialFn(ctx, network, address)
+	}
+	return nil, nil
+}
+func (m *mockRouter) Bind(ctx context.Context, network, address string, opts ...chain.BindOption) (net.Listener, error) {
+	return nil, nil
+}
+
+// mockHop implements hop.Hop.
+type mockHop struct {
+	selectFn func(ctx context.Context, opts ...hop.SelectOption) *chain.Node
+}
+
+func (m *mockHop) Select(ctx context.Context, opts ...hop.SelectOption) *chain.Node {
+	if m.selectFn != nil {
+		return m.selectFn(ctx, opts...)
+	}
+	return nil
+}
+
+type stubRateLimiter struct {
+	limiterFn func(key string) rate.Limiter
+}
+
+func (m *stubRateLimiter) Limiter(key string) rate.Limiter {
+	if m.limiterFn != nil {
+		return m.limiterFn(key)
+	}
+	return nil
+}
+
+type stubLimiter struct {
+	allowFn func(n int) bool
+}
+
+func (m *stubLimiter) Allow(n int) bool {
+	if m.allowFn != nil {
+		return m.allowFn(n)
+	}
+	return true
+}
+
+func (m *stubLimiter) Limit() float64 { return 0 }
+
+// mockRecorder implements recorder.Recorder.
+type mockRecorder struct{}
+
+func (m *mockRecorder) Record(ctx context.Context, b []byte, opts ...recorder.RecordOption) error {
+	return nil
+}
+func (m *mockRecorder) Close() error { return nil }
+
+type errorRecorder struct{}
+
+func (e *errorRecorder) Record(ctx context.Context, b []byte, opts ...recorder.RecordOption) error {
+	return errors.New("record error")
+}
+func (e *errorRecorder) Close() error { return nil }
+
+// stringConn is a net.Conn backed by bytes.Buffer for testing.
+type stringConn struct {
+	readBuf  *bytes.Buffer
+	writeBuf *bytes.Buffer
+	local    net.Addr
+	remote   net.Addr
+	closed   bool
+	mu       sync.Mutex
+}
+
+func newStringConn(data []byte) *stringConn {
+	return &stringConn{
+		readBuf:  bytes.NewBuffer(data),
+		writeBuf: new(bytes.Buffer),
+		local:    &net.TCPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 8080},
+		remote:   &net.TCPAddr{IP: net.IPv4(10, 0, 0, 1), Port: 12345},
+	}
+}
+
+func (c *stringConn) Read(b []byte) (int, error)  { return c.readBuf.Read(b) }
+func (c *stringConn) Write(b []byte) (int, error)  { return c.writeBuf.Write(b) }
+func (c *stringConn) Close() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.closed = true
+	return nil
+}
+func (c *stringConn) LocalAddr() net.Addr                { return c.local }
+func (c *stringConn) RemoteAddr() net.Addr               { return c.remote }
+func (c *stringConn) SetDeadline(t time.Time) error      { return nil }
+func (c *stringConn) SetReadDeadline(t time.Time) error  { return nil }
+func (c *stringConn) SetWriteDeadline(t time.Time) error { return nil }
+
+type packetConn struct {
+	*stringConn
+}
+
+func (c *packetConn) ReadFrom(b []byte) (int, net.Addr, error)  { return 0, nil, nil }
+func (c *packetConn) WriteTo(b []byte, addr net.Addr) (int, error) { return 0, nil }
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+func nopLog() logger.Logger { return xlogger.Nop() }
+
+func newTestHandler(opts ...handler.Option) *forwardHandler {
+	options := handler.Options{
+		Logger: nopLog(),
+		Router: &mockRouter{opts: &chain.RouterOptions{}},
+	}
+	for _, opt := range opts {
+		opt(&options)
+	}
+	return &forwardHandler{
+		options: options,
+		sniffer: &SnifferBuilder{},
+	}
+}
+
+func newInitdHandler(opts ...handler.Option) *forwardHandler {
+	h := newTestHandler(opts...)
+	_ = h.Init(xmd.NewMetadata(nil))
+	return h
+}
+
+// withRateLimiter is a helper to set the RateLimiter option.
+func withRateLimiter(rl rate.RateLimiter) handler.Option {
+	return func(o *handler.Options) {
+		o.RateLimiter = rl
+	}
+}
+
+// withRouter is a helper to set the Router option.
+func withRouter(r chain.Router) handler.Option {
+	return func(o *handler.Options) {
+		o.Router = r
+	}
+}
+
+// withRecorder is a helper to append a RecorderObject to the Recorders slice.
+func withRecorder(ro recorder.RecorderObject) handler.Option {
+	return func(o *handler.Options) {
+		o.Recorders = append(o.Recorders, ro)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// Test certificate helpers
+// ---------------------------------------------------------------------------
+
+func generateTestCertKey(t *testing.T) (*x509.Certificate, crypto.PrivateKey) {
+	t.Helper()
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		t.Fatalf("generate key: %v", err)
+	}
+	tmpl := &x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject:      pkix.Name{CommonName: "test"},
+		NotBefore:    time.Now().Add(-time.Hour),
+		NotAfter:     time.Now().Add(time.Hour),
+	}
+	certDER, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, &key.PublicKey, key)
+	if err != nil {
+		t.Fatalf("create certificate: %v", err)
+	}
+	cert, err := x509.ParseCertificate(certDER)
+	if err != nil {
+		t.Fatalf("parse certificate: %v", err)
+	}
+	return cert, key
+}
+
+func generateTestCertPEM(t *testing.T) (certPEM, keyPEM []byte) {
+	t.Helper()
+	cert, key := generateTestCertKey(t)
+	certPEM = pemEncode("CERTIFICATE", cert.Raw)
+	keyBytes := x509.MarshalPKCS1PrivateKey(key.(*rsa.PrivateKey))
+	keyPEM = pemEncode("RSA PRIVATE KEY", keyBytes)
+	return
+}
+
+func pemEncode(blockType string, der []byte) []byte {
+	block := &pem.Block{Type: blockType, Bytes: der}
+	return pem.EncodeToMemory(block)
+}
+
+func writeTempFile(t *testing.T, pattern string, data []byte) string {
+	t.Helper()
+	f, err := os.CreateTemp("", pattern)
+	if err != nil {
+		t.Fatalf("create temp file: %v", err)
+	}
+	if _, err := f.Write(data); err != nil {
+		f.Close()
+		os.Remove(f.Name())
+		t.Fatalf("write temp file: %v", err)
+	}
+	f.Close()
+	return f.Name()
+}

handler/forward/remote/metadata.go

@@ -7,7 +7,7 @@ import (
 	"time"
 
 	"github.com/go-gost/core/bypass"
-	md "github.com/go-gost/core/metadata"
+	mdata "github.com/go-gost/core/metadata"
 	mdutil "github.com/go-gost/x/metadata/util"
 	"github.com/go-gost/x/registry"
 )
@@ -28,7 +28,7 @@ type metadata struct {
 	mitmBypass  bypass.Bypass
 }
 
-func (h *forwardHandler) parseMetadata(md md.Metadata) (err error) {
+func (h *forwardHandler) parseMetadata(md mdata.Metadata) (err error) {
 	h.md.readTimeout = mdutil.GetDuration(md, "readTimeout")
 	if h.md.readTimeout <= 0 {
 		h.md.readTimeout = 15 * time.Second

handler/forward/remote/metadata_test.go

@@ -0,0 +1,110 @@
+package remote
+
+import (
+	"os"
+	"testing"
+	"time"
+
+	xmd "github.com/go-gost/x/metadata"
+)
+
+// ---------------------------------------------------------------------------
+// parseMetadata
+// ---------------------------------------------------------------------------
+
+func TestParseMetadata_Defaults(t *testing.T) {
+	h := newTestHandler()
+
+	err := h.parseMetadata(xmd.NewMetadata(nil))
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if h.md.readTimeout <= 0 {
+		t.Error("expected positive default readTimeout")
+	}
+	if h.md.sniffing {
+		t.Error("expected sniffing disabled by default")
+	}
+}
+
+func TestParseMetadata_CustomValues(t *testing.T) {
+	h := newTestHandler()
+	md := xmd.NewMetadata(map[string]any{
+		"readTimeout":                   "60s",
+		"http.keepalive":                true,
+		"proxyProtocol":                 2,
+		"sniffing":                      true,
+		"sniffing.timeout":              "5s",
+		"sniffing.websocket":            true,
+		"sniffing.websocket.sampleRate": 0.75,
+	})
+
+	err := h.parseMetadata(md)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if h.md.readTimeout != 60*time.Second {
+		t.Errorf("expected 60s, got %v", h.md.readTimeout)
+	}
+	if !h.md.httpKeepalive {
+		t.Error("expected httpKeepalive true")
+	}
+	if h.md.proxyProtocol != 2 {
+		t.Errorf("expected proxyProtocol 2, got %d", h.md.proxyProtocol)
+	}
+	if !h.md.sniffing {
+		t.Error("expected sniffing true")
+	}
+	if h.md.sniffingTimeout != 5*time.Second {
+		t.Errorf("expected 5s sniffingTimeout, got %v", h.md.sniffingTimeout)
+	}
+	if !h.md.sniffingWebsocket {
+		t.Error("expected sniffingWebsocket true")
+	}
+	if h.md.sniffingWebsocketSampleRate != 0.75 {
+		t.Errorf("expected 0.75, got %f", h.md.sniffingWebsocketSampleRate)
+	}
+}
+
+func TestParseMetadata_MITMCertError(t *testing.T) {
+	h := newTestHandler()
+	md := xmd.NewMetadata(map[string]any{
+		"mitm.certFile": "/nonexistent/cert.pem",
+		"mitm.keyFile":  "/nonexistent/key.pem",
+	})
+	err := h.parseMetadata(md)
+	if err == nil {
+		t.Fatal("expected error for non-existent cert file")
+	}
+}
+
+func TestParseMetadata_MITMCert(t *testing.T) {
+	certPEM, keyPEM := generateTestCertPEM(t)
+	certFile := writeTempFile(t, "cert-*.pem", certPEM)
+	defer os.Remove(certFile)
+	keyFile := writeTempFile(t, "key-*.pem", keyPEM)
+	defer os.Remove(keyFile)
+
+	h := newTestHandler()
+	md := xmd.NewMetadata(map[string]any{
+		"mitm.certFile": certFile,
+		"mitm.keyFile":  keyFile,
+		"mitm.alpn":     "h2",
+	})
+
+	err := h.parseMetadata(md)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if h.md.certificate == nil {
+		t.Error("expected certificate to be loaded")
+	}
+	if h.md.privateKey == nil {
+		t.Error("expected privateKey to be loaded")
+	}
+	if h.md.alpn != "h2" {
+		t.Errorf("expected alpn 'h2', got %s", h.md.alpn)
+	}
+}

handler/forward/remote/sniffing.go

@@ -0,0 +1,99 @@
+package remote
+
+import (
+	"bytes"
+	"context"
+	"crypto"
+	"crypto/x509"
+	"net"
+	"time"
+
+	"github.com/go-gost/core/bypass"
+	"github.com/go-gost/core/logger"
+	"github.com/go-gost/core/recorder"
+	xctx "github.com/go-gost/x/ctx"
+	ictx "github.com/go-gost/x/internal/ctx"
+	"github.com/go-gost/x/internal/net/proxyproto"
+	"github.com/go-gost/x/internal/util/forwarder"
+	"github.com/go-gost/x/internal/util/sniffing"
+	tls_util "github.com/go-gost/x/internal/util/tls"
+	xrecorder "github.com/go-gost/x/recorder"
+)
+
+// SnifferBuilder holds configuration for creating per-connection protocol sniffers.
+// It is populated once during Init and reused for each connection.
+type SnifferBuilder struct {
+	Websocket           bool
+	WebsocketSampleRate float64
+	Recorder            recorder.Recorder
+	RecorderOptions     *recorder.Options
+	Certificate         *x509.Certificate
+	PrivateKey          crypto.PrivateKey
+	ALPN                string
+	CertPool            tls_util.CertPool
+	MitmBypass          bypass.Bypass
+	ReadTimeout         time.Duration
+}
+
+// Build creates a new forwarder.Sniffer from the builder's configuration.
+func (b *SnifferBuilder) Build() *forwarder.Sniffer {
+	return &forwarder.Sniffer{
+		Websocket:           b.Websocket,
+		WebsocketSampleRate: b.WebsocketSampleRate,
+		Recorder:            b.Recorder,
+		RecorderOptions:     b.RecorderOptions,
+		Certificate:         b.Certificate,
+		PrivateKey:          b.PrivateKey,
+		NegotiatedProtocol:  b.ALPN,
+		CertPool:            b.CertPool,
+		MitmBypass:          b.MitmBypass,
+		ReadTimeout:         b.ReadTimeout,
+	}
+}
+
+// sniffingDial creates a dial function for the sniffing branch that wraps
+// Router.Dial with route recording and proxy protocol encapsulation.
+func (h *forwardHandler) sniffingDial(ctx context.Context, network, address string, ro *xrecorder.HandlerRecorderObject) (net.Conn, error) {
+	var buf bytes.Buffer
+	cc, err := h.options.Router.Dial(ictx.ContextWithBuffer(ctx, &buf), "tcp", address)
+	ro.Route = buf.String()
+	return proxyproto.WrapClientConn(
+		h.md.proxyProtocol,
+		xctx.SrcAddrFromContext(ctx),
+		xctx.DstAddrFromContext(ctx),
+		cc), err
+}
+
+// handleSniffedProtocol dispatches a sniffed connection to the protocol-specific
+// sniffer (HandleHTTP or HandleTLS). It returns (true, err) when the protocol was
+// handled and (false, nil) when the caller should fall through to raw forwarding.
+func (h *forwardHandler) handleSniffedProtocol(ctx context.Context, conn net.Conn, ro *xrecorder.HandlerRecorderObject, log logger.Logger, proto string) (handled bool, err error) {
+	switch proto {
+	case sniffing.ProtoHTTP, sniffing.ProtoTLS:
+		dial := func(ctx context.Context, network, address string) (net.Conn, error) {
+			return h.sniffingDial(ctx, network, address, ro)
+		}
+		sniffer := h.sniffer.Build()
+		if proto == sniffing.ProtoHTTP {
+			return true, sniffer.HandleHTTP(ctx, conn,
+				forwarder.WithService(h.options.Service),
+				forwarder.WithDial(dial),
+				forwarder.WithHop(h.getHop()),
+				forwarder.WithBypass(h.options.Bypass),
+				forwarder.WithHTTPKeepalive(h.md.httpKeepalive),
+				forwarder.WithRecorderObject(ro),
+				forwarder.WithLog(log),
+			)
+		}
+		return true, sniffer.HandleTLS(ctx, conn,
+			forwarder.WithService(h.options.Service),
+			forwarder.WithDial(dial),
+			forwarder.WithHop(h.getHop()),
+			forwarder.WithBypass(h.options.Bypass),
+			forwarder.WithRecorderObject(ro),
+			forwarder.WithLog(log),
+		)
+	default:
+		return false, nil
+	}
+}

handler/forward/remote/sniffing_test.go

@@ -0,0 +1,157 @@
+package remote
+
+import (
+	"context"
+	"errors"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/go-gost/core/chain"
+	"github.com/go-gost/x/internal/util/sniffing"
+	xrecorder "github.com/go-gost/x/recorder"
+)
+
+// ---------------------------------------------------------------------------
+// SnifferBuilder
+// ---------------------------------------------------------------------------
+
+func TestSnifferBuilder(t *testing.T) {
+	h := newTestHandler()
+	h.sniffer.Websocket = true
+	h.sniffer.WebsocketSampleRate = 0.5
+	h.sniffer.ReadTimeout = 30 * time.Second
+
+	sniffer := h.sniffer.Build()
+
+	if !sniffer.Websocket {
+		t.Error("expected Websocket to be true")
+	}
+	if sniffer.WebsocketSampleRate != 0.5 {
+		t.Errorf("expected 0.5, got %f", sniffer.WebsocketSampleRate)
+	}
+	if sniffer.ReadTimeout != 30*time.Second {
+		t.Errorf("expected 30s, got %v", sniffer.ReadTimeout)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// sniffingDial
+// ---------------------------------------------------------------------------
+
+func TestSniffingDial_Success(t *testing.T) {
+	server, client := net.Pipe()
+	defer server.Close()
+	defer client.Close()
+
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return server, nil
+		},
+	}))
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	cc, err := h.sniffingDial(context.Background(), "tcp", "example.com:80", ro)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer cc.Close()
+
+	if ro.Route == "" {
+		t.Log("route is empty (mock does not populate context buffer)")
+	}
+}
+
+func TestSniffingDial_RouterError(t *testing.T) {
+	expectedErr := errors.New("dial failed")
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return nil, expectedErr
+		},
+	}))
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	_, err := h.sniffingDial(context.Background(), "tcp", "example.com:80", ro)
+	if err == nil {
+		t.Fatal("expected error")
+	}
+	if !errors.Is(err, expectedErr) {
+		t.Errorf("expected %v, got %v", expectedErr, err)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// handleSniffedProtocol
+// ---------------------------------------------------------------------------
+
+func TestHandleSniffedProtocol_UnknownProto(t *testing.T) {
+	h := newInitdHandler()
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	handled, err := h.handleSniffedProtocol(context.Background(), conn, ro, nopLog(), "ssh")
+	if handled {
+		t.Error("expected handled=false for unknown proto")
+	}
+	if err != nil {
+		t.Errorf("expected nil error, got %v", err)
+	}
+}
+
+func TestHandleSniffedProtocol_EmptyProto(t *testing.T) {
+	h := newInitdHandler()
+	conn := newStringConn(nil)
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	handled, err := h.handleSniffedProtocol(context.Background(), conn, ro, nopLog(), "")
+	if handled {
+		t.Error("expected handled=false for empty proto")
+	}
+	if err != nil {
+		t.Errorf("expected nil error, got %v", err)
+	}
+}
+
+func TestHandleSniffedProtocol_HTTP(t *testing.T) {
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return nil, errors.New("dial not configured in test")
+		},
+	}))
+	conn := newStringConn([]byte("GET / HTTP/1.1\r\nHost: example.com\r\n\r\n"))
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	handled, err := h.handleSniffedProtocol(context.Background(), conn, ro, nopLog(), sniffing.ProtoHTTP)
+
+	if !handled {
+		t.Error("expected handled=true for HTTP proto")
+	}
+	if err == nil {
+		t.Log("sniffer processed HTTP request without error")
+	}
+}
+
+func TestHandleSniffedProtocol_TLS(t *testing.T) {
+	h := newInitdHandler(withRouter(&mockRouter{
+		opts: &chain.RouterOptions{},
+		dialFn: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return nil, errors.New("dial not configured in test")
+		},
+	}))
+	conn := newStringConn([]byte{
+		0x16, 0x03, 0x01, 0x00, 0x06, 0x01, 0x00, 0x00, 0x02, 0x03, 0x01,
+	})
+	ro := &xrecorder.HandlerRecorderObject{}
+
+	handled, err := h.handleSniffedProtocol(context.Background(), conn, ro, nopLog(), sniffing.ProtoTLS)
+
+	if !handled {
+		t.Error("expected handled=true for TLS proto")
+	}
+	if err == nil {
+		t.Log("sniffer processed TLS ClientHello without error")
+	}
+}

handler/forward/remote/util.go

@@ -0,0 +1,50 @@
+package remote
+
+import (
+	"context"
+	"errors"
+	"net"
+	"time"
+
+	xctx "github.com/go-gost/x/ctx"
+	xrecorder "github.com/go-gost/x/recorder"
+)
+
+var (
+	errRouterNotAvailable = errors.New("router not available")
+	errNodeNotAvailable   = errors.New("node not available")
+)
+
+// newRecorderObject creates a HandlerRecorderObject populated with connection
+// metadata (service, addresses, network type, session ID, client address).
+func (h *forwardHandler) newRecorderObject(ctx context.Context, conn net.Conn, start time.Time) *xrecorder.HandlerRecorderObject {
+	ro := &xrecorder.HandlerRecorderObject{
+		Service:    h.options.Service,
+		RemoteAddr: conn.RemoteAddr().String(),
+		LocalAddr:  conn.LocalAddr().String(),
+		Network:    "tcp",
+		Time:       start,
+		SID:        xctx.SidFromContext(ctx).String(),
+	}
+	if srcAddr := xctx.SrcAddrFromContext(ctx); srcAddr != nil {
+		ro.ClientAddr = srcAddr.String()
+	}
+	if _, ok := conn.(net.PacketConn); ok {
+		ro.Network = "udp"
+	}
+	return ro
+}
+
+func (h *forwardHandler) checkRateLimit(addr net.Addr) bool {
+	if h.options.RateLimiter == nil {
+		return true
+	}
+	if addr == nil {
+		return true
+	}
+	host, _, _ := net.SplitHostPort(addr.String())
+	if limiter := h.options.RateLimiter.Limiter(host); limiter != nil {
+		return limiter.Allow(1)
+	}
+	return true
+}

handler/forward/remote/util_test.go

@@ -0,0 +1,145 @@
+package remote
+
+import (
+	"context"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/go-gost/core/limiter/rate"
+	xctx "github.com/go-gost/x/ctx"
+)
+
+// ---------------------------------------------------------------------------
+// newRecorderObject
+// ---------------------------------------------------------------------------
+
+func TestNewRecorderObject_TCP(t *testing.T) {
+	h := newInitdHandler()
+	conn := newStringConn(nil)
+	start := time.Now()
+
+	ro := h.newRecorderObject(context.Background(), conn, start)
+
+	if ro.Network != "tcp" {
+		t.Errorf("expected network tcp, got %s", ro.Network)
+	}
+	if ro.RemoteAddr != "10.0.0.1:12345" {
+		t.Errorf("expected remote 10.0.0.1:12345, got %s", ro.RemoteAddr)
+	}
+	if ro.LocalAddr != "127.0.0.1:8080" {
+		t.Errorf("expected local 127.0.0.1:8080, got %s", ro.LocalAddr)
+	}
+	if !ro.Time.Equal(start) {
+		t.Errorf("expected time %v, got %v", start, ro.Time)
+	}
+}
+
+func TestNewRecorderObject_SID(t *testing.T) {
+	h := newInitdHandler()
+	conn := newStringConn(nil)
+	ctx := xctx.ContextWithSid(context.Background(), xctx.Sid("remote-sid"))
+
+	ro := h.newRecorderObject(ctx, conn, time.Now())
+
+	if ro.SID != "remote-sid" {
+		t.Errorf("expected SID 'remote-sid', got '%s'", ro.SID)
+	}
+}
+
+func TestNewRecorderObject_NilSrcAddr(t *testing.T) {
+	h := newInitdHandler()
+	conn := newStringConn(nil)
+
+	ro := h.newRecorderObject(context.Background(), conn, time.Now())
+
+	if ro.ClientAddr != "" {
+		t.Errorf("expected empty ClientAddr, got %s", ro.ClientAddr)
+	}
+}
+
+func TestNewRecorderObject_SrcAddr(t *testing.T) {
+	h := newInitdHandler()
+	conn := newStringConn(nil)
+	srcAddr := &net.TCPAddr{IP: net.IPv4(192, 168, 1, 1), Port: 54321}
+	ctx := xctx.ContextWithSrcAddr(context.Background(), srcAddr)
+
+	ro := h.newRecorderObject(ctx, conn, time.Now())
+
+	if ro.ClientAddr != "192.168.1.1:54321" {
+		t.Errorf("expected ClientAddr '192.168.1.1:54321', got '%s'", ro.ClientAddr)
+	}
+}
+
+func TestNewRecorderObject_UDP(t *testing.T) {
+	h := newInitdHandler()
+	conn := &packetConn{newStringConn(nil)}
+
+	ro := h.newRecorderObject(context.Background(), conn, time.Now())
+
+	if ro.Network != "udp" {
+		t.Errorf("expected network udp, got %s", ro.Network)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// checkRateLimit
+// ---------------------------------------------------------------------------
+
+func TestCheckRateLimit_NilLimiter(t *testing.T) {
+	h := newInitdHandler()
+	conn := newStringConn(nil)
+
+	if !h.checkRateLimit(conn.RemoteAddr()) {
+		t.Error("expected true when RateLimiter is nil")
+	}
+}
+
+func TestCheckRateLimit_NilAddr(t *testing.T) {
+	h := newInitdHandler(withRateLimiter(&stubRateLimiter{
+		limiterFn: func(key string) rate.Limiter {
+			return &stubLimiter{allowFn: func(n int) bool { return false }}
+		},
+	}))
+
+	if !h.checkRateLimit(nil) {
+		t.Error("expected true when addr is nil")
+	}
+}
+
+func TestCheckRateLimit_Allowed(t *testing.T) {
+	h := newInitdHandler(withRateLimiter(&stubRateLimiter{
+		limiterFn: func(key string) rate.Limiter {
+			return &stubLimiter{allowFn: func(n int) bool { return true }}
+		},
+	}))
+	conn := newStringConn(nil)
+
+	if !h.checkRateLimit(conn.RemoteAddr()) {
+		t.Error("expected true when limiter allows")
+	}
+}
+
+func TestCheckRateLimit_Blocked(t *testing.T) {
+	h := newInitdHandler(withRateLimiter(&stubRateLimiter{
+		limiterFn: func(key string) rate.Limiter {
+			return &stubLimiter{allowFn: func(n int) bool { return false }}
+		},
+	}))
+	conn := newStringConn(nil)
+
+	if h.checkRateLimit(conn.RemoteAddr()) {
+		t.Error("expected false when limiter blocks")
+	}
+}
+
+func TestCheckRateLimit_NoLimiterForKey(t *testing.T) {
+	h := newInitdHandler(withRateLimiter(&stubRateLimiter{
+		limiterFn: func(key string) rate.Limiter { return nil },
+	}))
+	conn := newStringConn(nil)
+
+	if !h.checkRateLimit(conn.RemoteAddr()) {
+		t.Error("expected true when no limiter found for key")
+	}
+}