Set the default TCP keep alive period

common/dialer/default.go

@@ -63,6 +63,9 @@ func NewDefault(router adapter.Router, options option.DialerOptions) (*DefaultDi
 	} else {
 		dialer.Timeout = C.TCPTimeout
 	}
+	// TODO: Add an option to customize the keep alive period
+	dialer.KeepAlive = C.TCPKeepAliveInitial
+	dialer.Control = control.Append(dialer.Control, control.SetKeepAlivePeriod(C.TCPKeepAliveInitial, C.TCPKeepAliveInterval))
 	var udpFragment bool
 	if options.UDPFragment != nil {
 		udpFragment = *options.UDPFragment

constant/timeout.go

@@ -3,6 +3,8 @@ package constant
 import "time"
 
 const (
+	TCPKeepAliveInitial        = 10 * time.Minute
+	TCPKeepAliveInterval       = 75 * time.Second
 	TCPTimeout                 = 5 * time.Second
 	ReadPayloadTimeout         = 300 * time.Millisecond
 	DNSTimeout                 = 10 * time.Second

inbound/default_tcp.go

@@ -5,7 +5,9 @@ import (
 	"net"
 
 	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/log"
+	"github.com/sagernet/sing/common/control"
 	E "github.com/sagernet/sing/common/exceptions"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
@@ -16,6 +18,9 @@ func (a *myInboundAdapter) ListenTCP() (net.Listener, error) {
 	bindAddr := M.SocksaddrFrom(a.listenOptions.Listen.Build(), a.listenOptions.ListenPort)
 	var tcpListener net.Listener
 	var listenConfig net.ListenConfig
+	// TODO: Add an option to customize the keep alive period
+	listenConfig.KeepAlive = C.TCPKeepAliveInitial
+	listenConfig.Control = control.Append(listenConfig.Control, control.SetKeepAlivePeriod(C.TCPKeepAliveInitial, C.TCPKeepAliveInterval))
 	if a.listenOptions.TCPMultiPath {
 		if !go121Available {
 			return nil, E.New("MultiPath TCP requires go1.21, please recompile your binary.")