From 76e2ce011d94b6f553ee925be51756a84f6de631 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=96=E7=95=8C?= <i@sekai.icu>
Date: Mon, 8 Apr 2024 17:26:08 +0800
Subject: [PATCH] Add control.SetKeepAlivePeriod

---
 common/control/tcp_keep_alive_linux.go | 29 ++++++++++++++++++++++++++
 common/control/tcp_keep_alive_stub.go  | 11 ++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 common/control/tcp_keep_alive_linux.go
 create mode 100644 common/control/tcp_keep_alive_stub.go

diff --git a/common/control/tcp_keep_alive_linux.go b/common/control/tcp_keep_alive_linux.go
new file mode 100644
index 00000000..7c84a67c
--- /dev/null
+++ b/common/control/tcp_keep_alive_linux.go
@@ -0,0 +1,29 @@
+package control
+
+import (
+	"syscall"
+	"time"
+	_ "unsafe"
+
+	E "github.com/sagernet/sing/common/exceptions"
+	N "github.com/sagernet/sing/common/network"
+
+	"golang.org/x/sys/unix"
+)
+
+func SetKeepAlivePeriod(idle time.Duration, interval time.Duration) Func {
+	return func(network, address string, conn syscall.RawConn) error {
+		if N.NetworkName(network) != N.NetworkTCP {
+			return nil
+		}
+		return Raw(conn, func(fd uintptr) error {
+			return E.Errors(
+				unix.SetsockoptInt(int(fd), unix.IPPROTO_TCP, unix.TCP_KEEPIDLE, int(roundDurationUp(idle, 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
diff --git a/common/control/tcp_keep_alive_stub.go b/common/control/tcp_keep_alive_stub.go
new file mode 100644
index 00000000..180d8d3f
--- /dev/null
+++ b/common/control/tcp_keep_alive_stub.go
@@ -0,0 +1,11 @@
+//go:build !linux
+
+package control
+
+import (
+	"time"
+)
+
+func SetKeepAlivePeriod(idle time.Duration, interval time.Duration) Func {
+	return nil
+}