Add control.SetKeepAlivePeriod

Author: nekohasekai

common/control/tcp_keep_alive_linux.go

@@ -0,0 +1,25 @@
+package control
+
+import (
+	E "github.com/sagernet/sing/common/exceptions"
+	"golang.org/x/sys/unix"
+	"syscall"
+	"time"
+
+	_ "unsafe"
+)
+
+func SetKeepAlivePeriod(keepCnt int, keepIdle time.Duration, interval time.Duration) Func {
+	return func(network, address string, conn syscall.RawConn) error {
+		return Raw(conn, func(fd uintptr) error {
+			return E.Errors(
+				unix.SetsockoptInt(int(fd), unix.IPPROTO_TCP, unix.TCP_KEEPCNT, keepCnt),
+				unix.SetsockoptInt(int(fd), unix.IPPROTO_TCP, unix.TCP_KEEPIDLE, int(roundDurationUp(keepIdle, time.Second))),
+				unix.SetsockoptInt(int(fd), unix.IPPROTO_TCP, unix.TCP_KEEPINTVL, int(roundDurationUp(interval, time.Second))),
+			)
+		})
+	}
+}
+
+//go:linkname roundDurationUp net.roundDurationUp
+func roundDurationUp(d time.Duration, to time.Duration) time.Duration

common/control/tcp_keep_alive_stub.go

@@ -0,0 +1,11 @@
+//go:build !linux
+
+package control
+
+import (
+	"time"
+)
+
+func SetKeepAlivePeriod(keepCnt int, keepIdle time.Duration, interval time.Duration) Func {
+	return nil
+}