add http body rewrite for forward handler

config/config.go

@@ -376,6 +376,13 @@ type HTTPURLRewriteConfig struct {
 	Replacement string
 }
 
+type HTTPBodyRewriteConfig struct {
+	// filter by MIME types
+	Type        string
+	Match       string
+	Replacement string
+}
+
 type NodeFilterConfig struct {
 	Host     string `yaml:",omitempty" json:"host,omitempty"`
 	Protocol string `yaml:",omitempty" json:"protocol,omitempty"`
@@ -383,10 +390,16 @@ type NodeFilterConfig struct {
 }
 
 type HTTPNodeConfig struct {
-	Host    string                 `yaml:",omitempty" json:"host,omitempty"`
-	Header  map[string]string      `yaml:",omitempty" json:"header,omitempty"`
+	// rewrite host header
+	Host string `yaml:",omitempty" json:"host,omitempty"`
+	// additional request header
+	Header map[string]string `yaml:",omitempty" json:"header,omitempty"`
+	// rewrite URL
 	Rewrite []HTTPURLRewriteConfig `yaml:",omitempty" json:"rewrite,omitempty"`
-	Auth    *AuthConfig            `yaml:",omitempty" json:"auth,omitempty"`
+	// rewrite response body
+	RewriteBody []HTTPBodyRewriteConfig `yaml:"rewriteBody,omitempty" json:"rewriteBody,omitempty"`
+	// HTTP basic auth
+	Auth *AuthConfig `yaml:",omitempty" json:"auth,omitempty"`
 }
 
 type TLSNodeConfig struct {

config/parsing/node/parse.go

@@ -193,12 +193,21 @@ func ParseNode(hop string, cfg *config.NodeConfig, log logger.Logger) (*chain.No
 		}
 		for _, v := range cfg.HTTP.Rewrite {
 			if pattern, _ := regexp.Compile(v.Match); pattern != nil {
-				settings.Rewrite = append(settings.Rewrite, chain.HTTPURLRewriteSetting{
+				settings.RewriteURL = append(settings.RewriteURL, chain.HTTPURLRewriteSetting{
 					Pattern:     pattern,
 					Replacement: v.Replacement,
 				})
 			}
 		}
+		for _, v := range cfg.HTTP.RewriteBody {
+			if pattern, _ := regexp.Compile(v.Match); pattern != nil {
+				settings.RewriteBody = append(settings.RewriteBody, chain.HTTPBodyRewriteSettings{
+					Type:        v.Type,
+					Pattern:     pattern,
+					Replacement: []byte(v.Replacement),
+				})
+			}
+		}
 		opts = append(opts, chain.HTTPNodeOption(settings))
 	}
 

dialer/icmp/dialer.go

@@ -19,9 +19,11 @@ import (
 
 func init() {
 	registry.DialerRegistry().Register("icmp", NewDialer)
+	registry.DialerRegistry().Register("icmp6", NewDialer6)
 }
 
 type icmpDialer struct {
+	ip6          bool
 	sessions     map[string]*quicSession
 	sessionMutex sync.Mutex
 	logger       logger.Logger
@@ -42,6 +44,19 @@ func NewDialer(opts ...dialer.Option) dialer.Dialer {
 	}
 }
 
+func NewDialer6(opts ...dialer.Option) dialer.Dialer {
+	options := dialer.Options{}
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	return &icmpDialer{
+		ip6:      true,
+		sessions: make(map[string]*quicSession),
+		logger:   options.Logger,
+		options:  options,
+	}
+}
 func (d *icmpDialer) Init(md md.Metadata) (err error) {
 	if err = d.parseMetadata(md); err != nil {
 		return
@@ -71,7 +86,11 @@ func (d *icmpDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialO
 		}
 
 		var pc net.PacketConn
-		pc, err = icmp.ListenPacket("ip4:icmp", "")
+		if d.ip6 {
+			pc, err = icmp.ListenPacket("ip6:ipv6-icmp", "")
+		} else {
+			pc, err = icmp.ListenPacket("ip4:icmp", "")
+		}
 		if err != nil {
 			return
 		}
@@ -81,7 +100,7 @@ func (d *icmpDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialO
 			id = rand.New(rand.NewSource(time.Now().UnixNano())).Intn(math.MaxUint16) + 1
 			raddr.Port = id
 		}
-		pc = icmp_pkg.ClientConn(pc, id)
+		pc = icmp_pkg.ClientConn(d.ip6, pc, id)
 
 		session, err = d.initSession(ctx, raddr, pc)
 		if err != nil {

dialer/icmp/metadata.go

@@ -14,21 +14,14 @@ type metadata struct {
 }
 
 func (d *icmpDialer) parseMetadata(md mdata.Metadata) (err error) {
-	const (
-		keepAlive        = "keepAlive"
-		keepAlivePeriod  = "ttl"
-		handshakeTimeout = "handshakeTimeout"
-		maxIdleTimeout   = "maxIdleTimeout"
-	)
-
-	if mdutil.GetBool(md, keepAlive) {
-		d.md.keepAlivePeriod = mdutil.GetDuration(md, keepAlivePeriod)
+	if mdutil.GetBool(md, "keepalive") {
+		d.md.keepAlivePeriod = mdutil.GetDuration(md, "ttl")
 		if d.md.keepAlivePeriod <= 0 {
 			d.md.keepAlivePeriod = 10 * time.Second
 		}
 	}
-	d.md.handshakeTimeout = mdutil.GetDuration(md, handshakeTimeout)
-	d.md.maxIdleTimeout = mdutil.GetDuration(md, maxIdleTimeout)
+	d.md.handshakeTimeout = mdutil.GetDuration(md, "handshakeTimeout")
+	d.md.maxIdleTimeout = mdutil.GetDuration(md, "maxIdleTimeout")
 
 	return
 }

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/asaskevich/govalidator v0.0.0-20210307081110-f21760c49a8d
 	github.com/gin-contrib/cors v1.6.0
 	github.com/gin-gonic/gin v1.9.1
-	github.com/go-gost/core v0.1.0
+	github.com/go-gost/core v0.1.1
 	github.com/go-gost/gosocks4 v0.0.1
 	github.com/go-gost/gosocks5 v0.4.2
 	github.com/go-gost/plugin v0.0.0-20240103125338-9c84e29cb81a

go.sum

@@ -53,8 +53,8 @@ github.com/gin-contrib/sse v0.1.0 h1:Y/yl/+YNO8GZSjAhjMsSuLt29uWRFHdHYUb5lYOV9qE
 github.com/gin-contrib/sse v0.1.0/go.mod h1:RHrZQHXnP2xjPF+u1gW/2HnVO7nvIa9PG3Gm+fLHvGI=
 github.com/gin-gonic/gin v1.9.1 h1:4idEAncQnU5cB7BeOkPtxjfCSye0AAm1R0RVIqJ+Jmg=
 github.com/gin-gonic/gin v1.9.1/go.mod h1:hPrL7YrpYKXt5YId3A/Tnip5kqbEAP+KLuI3SUcPTeU=
-github.com/go-gost/core v0.1.0 h1:LJJc8PIlRflE8ZIpxls+wYX1e8OGB0nUKJYh8HevM4U=
-github.com/go-gost/core v0.1.0/go.mod h1:WGI43jOka7FAsSAwi/fSMaqxdR+E339ycb4NBGlFr6A=
+github.com/go-gost/core v0.1.1 h1:8joR9KJYBvpurNu3i0zqN9orQthVzOjhtT4STumwNF0=
+github.com/go-gost/core v0.1.1/go.mod h1:WGI43jOka7FAsSAwi/fSMaqxdR+E339ycb4NBGlFr6A=
 github.com/go-gost/gosocks4 v0.0.1 h1:+k1sec8HlELuQV7rWftIkmy8UijzUt2I6t+iMPlGB2s=
 github.com/go-gost/gosocks4 v0.0.1/go.mod h1:3B6L47HbU/qugDg4JnoFPHgJXE43Inz8Bah1QaN9qCc=
 github.com/go-gost/gosocks5 v0.4.2 h1:IianxHTkACPqCwiOAT3MHoMdSUl+SEPSRu1ikawC1Pc=

handler/forward/local/handler.go

@@ -2,6 +2,7 @@ package local
 
 import (
 	"bufio"
+	"bytes"
 	"context"
 	"crypto/tls"
 	"errors"
@@ -179,8 +180,9 @@ func (h *forwardHandler) Handle(ctx context.Context, conn net.Conn, opts ...hand
 func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remoteAddr net.Addr, log logger.Logger) (err error) {
 	br := bufio.NewReader(rw)
 
-	var cc net.Conn
 	for {
+		var cc net.Conn
+
 		resp := &http.Response{
 			ProtoMajor: 1,
 			ProtoMinor: 1,
@@ -241,6 +243,7 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 			})
 			log.Debugf("find node for host %s -> %s(%s)", req.Host, target.Name, target.Addr)
 
+			var bodyRewrites []chain.HTTPBodyRewriteSettings
 			if httpSettings := target.Options().HTTP; httpSettings != nil {
 				if auther := httpSettings.Auther; auther != nil {
 					username, password, _ := req.BasicAuth()
@@ -261,7 +264,7 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 					req.Header.Set(k, v)
 				}
 
-				for _, re := range httpSettings.Rewrite {
+				for _, re := range httpSettings.RewriteURL {
 					if re.Pattern.MatchString(req.URL.Path) {
 						if s := re.Pattern.ReplaceAllString(req.URL.Path, re.Replacement); s != "" {
 							req.URL.Path = s
@@ -269,6 +272,8 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 						}
 					}
 				}
+
+				bodyRewrites = httpSettings.RewriteBody
 			}
 
 			cc, err = h.options.Router.Dial(ctx, "tcp", target.Addr)
@@ -329,6 +334,11 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 					log.Trace(string(dump))
 				}
 
+				if err := h.rewriteBody(res, bodyRewrites...); err != nil {
+					log.Errorf("rewrite body: %v", err)
+					return
+				}
+
 				if err = res.Write(rw); err != nil {
 					log.Errorf("write response from node %s(%s): %v", target.Name, target.Addr, err)
 				}
@@ -348,6 +358,54 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 	return
 }
 
+func (h *forwardHandler) rewriteBody(resp *http.Response, rewrites ...chain.HTTPBodyRewriteSettings) error {
+	if resp == nil || len(rewrites) == 0 || resp.ContentLength <= 0 {
+		return nil
+	}
+
+	if encoding := resp.Header.Get("Content-Encoding"); encoding != "" {
+		return nil
+	}
+
+	body, err := drainBody(resp.Body)
+	if err != nil || body == nil {
+		return err
+	}
+
+	contentType, _, _ := strings.Cut(resp.Header.Get("Content-Type"), ";")
+	for _, rewrite := range rewrites {
+		rewriteType := rewrite.Type
+		if rewriteType == "" {
+			rewriteType = "text/html"
+		}
+		if rewriteType != "*" && !strings.Contains(rewriteType, contentType) {
+			continue
+		}
+
+		body = rewrite.Pattern.ReplaceAll(body, rewrite.Replacement)
+	}
+
+	resp.Body = io.NopCloser(bytes.NewReader(body))
+	resp.ContentLength = int64(len(body))
+
+	return nil
+}
+
+func drainBody(b io.ReadCloser) (body []byte, err error) {
+	if b == nil || b == http.NoBody {
+		// No copying needed. Preserve the magic sentinel meaning of NoBody.
+		return nil, nil
+	}
+	var buf bytes.Buffer
+	if _, err = buf.ReadFrom(b); err != nil {
+		return nil, err
+	}
+	if err = b.Close(); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
 func (h *forwardHandler) checkRateLimit(addr net.Addr) bool {
 	if h.options.RateLimiter == nil {
 		return true

handler/forward/remote/handler.go

@@ -2,6 +2,7 @@ package remote
 
 import (
 	"bufio"
+	"bytes"
 	"context"
 	"crypto/tls"
 	"errors"
@@ -179,9 +180,9 @@ func (h *forwardHandler) Handle(ctx context.Context, conn net.Conn, opts ...hand
 
 func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remoteAddr net.Addr, localAddr net.Addr, log logger.Logger) (err error) {
 	br := bufio.NewReader(rw)
-	var cc net.Conn
 
 	for {
+		var cc net.Conn
 		resp := &http.Response{
 			ProtoMajor: 1,
 			ProtoMinor: 1,
@@ -242,6 +243,7 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 			})
 			log.Debugf("find node for host %s -> %s(%s)", req.Host, target.Name, target.Addr)
 
+			var bodyRewrites []chain.HTTPBodyRewriteSettings
 			if httpSettings := target.Options().HTTP; httpSettings != nil {
 				if auther := httpSettings.Auther; auther != nil {
 					username, password, _ := req.BasicAuth()
@@ -261,7 +263,7 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 					req.Header.Set(k, v)
 				}
 
-				for _, re := range httpSettings.Rewrite {
+				for _, re := range httpSettings.RewriteURL {
 					if re.Pattern.MatchString(req.URL.Path) {
 						if s := re.Pattern.ReplaceAllString(req.URL.Path, re.Replacement); s != "" {
 							req.URL.Path = s
@@ -269,6 +271,8 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 						}
 					}
 				}
+
+				bodyRewrites = httpSettings.RewriteBody
 			}
 
 			cc, err = h.options.Router.Dial(ctx, "tcp", target.Addr)
@@ -331,6 +335,11 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 					log.Trace(string(dump))
 				}
 
+				if err := h.rewriteBody(res, bodyRewrites...); err != nil {
+					log.Errorf("rewrite body: %v", err)
+					return
+				}
+
 				if err = res.Write(rw); err != nil {
 					log.Errorf("write response from node %s(%s): %v", target.Name, target.Addr, err)
 				}
@@ -350,6 +359,50 @@ func (h *forwardHandler) handleHTTP(ctx context.Context, rw io.ReadWriter, remot
 	return
 }
 
+func (h *forwardHandler) rewriteBody(resp *http.Response, rewrites ...chain.HTTPBodyRewriteSettings) error {
+	if resp == nil || len(rewrites) == 0 || resp.ContentLength <= 0 {
+		return nil
+	}
+
+	body, err := drainBody(resp.Body)
+	if err != nil || body == nil {
+		return err
+	}
+
+	contentType, _, _ := strings.Cut(resp.Header.Get("Content-Type"), ";")
+	for _, rewrite := range rewrites {
+		rewriteType := rewrite.Type
+		if rewriteType == "" {
+			rewriteType = "text/html"
+		}
+		if rewriteType != "*" && !strings.Contains(rewriteType, contentType) {
+			continue
+		}
+
+		body = rewrite.Pattern.ReplaceAll(body, rewrite.Replacement)
+	}
+
+	resp.Body = io.NopCloser(bytes.NewReader(body))
+	resp.ContentLength = int64(len(body))
+
+	return nil
+}
+
+func drainBody(b io.ReadCloser) (body []byte, err error) {
+	if b == nil || b == http.NoBody {
+		// No copying needed. Preserve the magic sentinel meaning of NoBody.
+		return nil, nil
+	}
+	var buf bytes.Buffer
+	if _, err = buf.ReadFrom(b); err != nil {
+		return nil, err
+	}
+	if err = b.Close(); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
 func (h *forwardHandler) checkRateLimit(addr net.Addr) bool {
 	if h.options.RateLimiter == nil {
 		return true

handler/redirect/tcp/metadata.go

@@ -14,12 +14,8 @@ type metadata struct {
 }
 
 func (h *redirectHandler) parseMetadata(md mdata.Metadata) (err error) {
-	const (
-		tproxy   = "tproxy"
-		sniffing = "sniffing"
-	)
-	h.md.tproxy = mdutil.GetBool(md, tproxy)
-	h.md.sniffing = mdutil.GetBool(md, sniffing)
+	h.md.tproxy = mdutil.GetBool(md, "tproxy")
+	h.md.sniffing = mdutil.GetBool(md, "sniffing")
 	h.md.sniffingTimeout = mdutil.GetDuration(md, "sniffing.timeout")
 	return
 }

internal/util/icmp/conn.go

@@ -12,6 +12,12 @@ import (
 	"github.com/go-gost/core/logger"
 	"golang.org/x/net/icmp"
 	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+const (
+	ICMPv4 = 1
+	ICMPv6 = 58
 )
 
 const (
@@ -79,13 +85,15 @@ func (m *message) Decode(b []byte) (n int, err error) {
 }
 
 type clientConn struct {
+	ip6 bool
 	net.PacketConn
 	id  int
 	seq uint32
 }
 
-func ClientConn(conn net.PacketConn, id int) net.PacketConn {
+func ClientConn(ip6 bool, conn net.PacketConn, id int) net.PacketConn {
 	return &clientConn{
+		ip6:        ip6,
 		PacketConn: conn,
 		id:         id,
 	}
@@ -101,13 +109,17 @@ func (c *clientConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
 			return
 		}
 
-		m, err := icmp.ParseMessage(1, buf[:n])
+		proto := ICMPv4
+		if c.ip6 {
+			proto = ICMPv6
+		}
+		m, err := icmp.ParseMessage(proto, buf[:n])
 		if err != nil {
 			// logger.Default().Error("icmp: parse message %v", err)
 			return 0, addr, err
 		}
 		echo, ok := m.Body.(*icmp.Echo)
-		if !ok || m.Type != ipv4.ICMPTypeEchoReply {
+		if !ok || m.Type != ipv4.ICMPTypeEchoReply && m.Type != ipv6.ICMPTypeEchoReply {
 			// logger.Default().Warnf("icmp: invalid type %s (discarded)", m.Type)
 			continue // discard
 		}
@@ -135,6 +147,7 @@ func (c *clientConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
 		addr = &net.UDPAddr{
 			IP:   v.IP,
 			Port: c.id,
+			Zone: v.Zone,
 		}
 	}
 	// logger.Default().Infof("icmp: read from: %v %d", addr, n)
@@ -146,7 +159,7 @@ func (c *clientConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
 	// logger.Default().Infof("icmp: write to: %v %d", addr, len(b))
 	switch v := addr.(type) {
 	case *net.UDPAddr:
-		addr = &net.IPAddr{IP: v.IP}
+		addr = &net.IPAddr{IP: v.IP, Zone: v.Zone}
 	}
 
 	buf := bufpool.Get(writeBufferSize)
@@ -170,6 +183,10 @@ func (c *clientConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
 		Code: 0,
 		Body: &echo,
 	}
+	if c.ip6 {
+		m.Type = ipv6.ICMPTypeEchoRequest
+	}
+
 	wb, err := m.Marshal(nil)
 	if err != nil {
 		return 0, err
@@ -180,12 +197,14 @@ func (c *clientConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
 }
 
 type serverConn struct {
+	ip6 bool
 	net.PacketConn
 	seqs [65535]uint32
 }
 
-func ServerConn(conn net.PacketConn) net.PacketConn {
+func ServerConn(ip6 bool, conn net.PacketConn) net.PacketConn {
 	return &serverConn{
+		ip6:        ip6,
 		PacketConn: conn,
 	}
 }
@@ -200,14 +219,18 @@ func (c *serverConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
 			return
 		}
 
-		m, err := icmp.ParseMessage(1, buf[:n])
+		proto := ICMPv4
+		if c.ip6 {
+			proto = ICMPv6
+		}
+		m, err := icmp.ParseMessage(proto, buf[:n])
 		if err != nil {
 			// logger.Default().Error("icmp: parse message %v", err)
 			return 0, addr, err
 		}
 
 		echo, ok := m.Body.(*icmp.Echo)
-		if !ok || m.Type != ipv4.ICMPTypeEcho || echo.ID <= 0 {
+		if !ok || echo.ID <= 0 || m.Type != ipv4.ICMPTypeEcho && m.Type != ipv6.ICMPTypeEchoRequest {
 			// logger.Default().Warnf("icmp: invalid type %s (discarded)", m.Type)
 			continue
 		}
@@ -229,6 +252,7 @@ func (c *serverConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
 			addr = &net.UDPAddr{
 				IP:   v.IP,
 				Port: echo.ID,
+				Zone: v.Zone,
 			}
 		}
 		break
@@ -244,7 +268,7 @@ func (c *serverConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
 	var id int
 	switch v := addr.(type) {
 	case *net.UDPAddr:
-		addr = &net.IPAddr{IP: v.IP}
+		addr = &net.IPAddr{IP: v.IP, Zone: v.Zone}
 		id = v.Port
 	}
 
@@ -275,6 +299,10 @@ func (c *serverConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
 		Code: 0,
 		Body: &echo,
 	}
+	if c.ip6 {
+		m.Type = ipv6.ICMPTypeEchoReply
+	}
+
 	wb, err := m.Marshal(nil)
 	if err != nil {
 		return 0, err

listener/icmp/listener.go

@@ -19,9 +19,11 @@ import (
 
 func init() {
 	registry.ListenerRegistry().Register("icmp", NewListener)
+	registry.ListenerRegistry().Register("icmp6", NewListener6)
 }
 
 type icmpListener struct {
+	ip6     bool
 	ln      quic.EarlyListener
 	cqueue  chan net.Conn
 	errChan chan error
@@ -41,6 +43,18 @@ func NewListener(opts ...listener.Option) listener.Listener {
 	}
 }
 
+func NewListener6(opts ...listener.Option) listener.Listener {
+	options := listener.Options{}
+	for _, opt := range opts {
+		opt(&options)
+	}
+	return &icmpListener{
+		ip6:     true,
+		logger:  options.Logger,
+		options: options,
+	}
+}
+
 func (l *icmpListener) Init(md md.Metadata) (err error) {
 	if err = l.parseMetadata(md); err != nil {
 		return
@@ -52,11 +66,15 @@ func (l *icmpListener) Init(md md.Metadata) (err error) {
 	}
 
 	var conn net.PacketConn
-	conn, err = icmp.ListenPacket("ip4:icmp", addr)
+	if l.ip6 {
+		conn, err = icmp.ListenPacket("ip6:ipv6-icmp", addr)
+	} else {
+		conn, err = icmp.ListenPacket("ip4:icmp", addr)
+	}
 	if err != nil {
 		return
 	}
-	conn = icmp_pkg.ServerConn(conn)
+	conn = icmp_pkg.ServerConn(l.ip6, conn)
 	conn = metrics.WrapPacketConn(l.options.Service, conn)
 	conn = stats.WrapPacketConn(conn, l.options.Stats)
 	conn = admission.WrapPacketConn(l.options.Admission, conn)

listener/icmp/metadata.go

@@ -20,28 +20,19 @@ type metadata struct {
 }
 
 func (l *icmpListener) parseMetadata(md mdata.Metadata) (err error) {
-	const (
-		keepAlive        = "keepAlive"
-		keepAlivePeriod  = "ttl"
-		handshakeTimeout = "handshakeTimeout"
-		maxIdleTimeout   = "maxIdleTimeout"
-
-		backlog = "backlog"
-	)
-
-	l.md.backlog = mdutil.GetInt(md, backlog)
+	l.md.backlog = mdutil.GetInt(md, "backlog")
 	if l.md.backlog <= 0 {
 		l.md.backlog = defaultBacklog
 	}
 
-	if mdutil.GetBool(md, keepAlive) {
-		l.md.keepAlivePeriod = mdutil.GetDuration(md, keepAlivePeriod)
+	if mdutil.GetBool(md, "keepalive") {
+		l.md.keepAlivePeriod = mdutil.GetDuration(md, "ttl")
 		if l.md.keepAlivePeriod <= 0 {
 			l.md.keepAlivePeriod = 10 * time.Second
 		}
 	}
-	l.md.handshakeTimeout = mdutil.GetDuration(md, handshakeTimeout)
-	l.md.maxIdleTimeout = mdutil.GetDuration(md, maxIdleTimeout)
+	l.md.handshakeTimeout = mdutil.GetDuration(md, "handshakeTimeout")
+	l.md.maxIdleTimeout = mdutil.GetDuration(md, "maxIdleTimeout")
 
 	return
 }

listener/redirect/tcp/metadata.go

@@ -11,10 +11,7 @@ type metadata struct {
 }
 
 func (l *redirectListener) parseMetadata(md mdata.Metadata) (err error) {
-	const (
-		tproxy = "tproxy"
-	)
-	l.md.tproxy = mdutil.GetBool(md, tproxy)
+	l.md.tproxy = mdutil.GetBool(md, "tproxy")
 	l.md.mptcp = mdutil.GetBool(md, "mptcp")
 	return
 }