From 32783047b171039487cba34ab50da644f5eabbea Mon Sep 17 00:00:00 2001
From: gVisor bot <gvisor-bot@google.com>
Date: Wed, 29 Aug 2018 15:00:12 +0800
Subject: [PATCH] Improve: Better handling of TCP connections

---
 adapters/remote/direct.go      | 2 +-
 adapters/remote/shadowsocks.go | 2 +-
 adapters/remote/socks5.go      | 3 +--
 adapters/remote/util.go        | 7 +++++++
 4 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/adapters/remote/direct.go b/adapters/remote/direct.go
index ac46c4a7..9d22f948 100644
--- a/adapters/remote/direct.go
+++ b/adapters/remote/direct.go
@@ -36,7 +36,7 @@ func (d *Direct) Generator(addr *C.Addr) (adapter C.ProxyAdapter, err error) {
 	if err != nil {
 		return
 	}
-	c.(*net.TCPConn).SetKeepAlive(true)
+	tcpKeepAlive(c)
 	return &DirectAdapter{conn: c}, nil
 }
 
diff --git a/adapters/remote/shadowsocks.go b/adapters/remote/shadowsocks.go
index 6323a897..07590c9d 100644
--- a/adapters/remote/shadowsocks.go
+++ b/adapters/remote/shadowsocks.go
@@ -46,7 +46,7 @@ func (ss *ShadowSocks) Generator(addr *C.Addr) (adapter C.ProxyAdapter, err erro
 	if err != nil {
 		return nil, fmt.Errorf("%s connect error", ss.server)
 	}
-	c.(*net.TCPConn).SetKeepAlive(true)
+	tcpKeepAlive(c)
 	c = ss.cipher.StreamConn(c)
 	_, err = c.Write(serializesSocksAddr(addr))
 	return &ShadowsocksAdapter{conn: c}, err
diff --git a/adapters/remote/socks5.go b/adapters/remote/socks5.go
index dec9adde..8d82f183 100644
--- a/adapters/remote/socks5.go
+++ b/adapters/remote/socks5.go
@@ -44,8 +44,7 @@ func (ss *Socks5) Generator(addr *C.Addr) (adapter C.ProxyAdapter, err error) {
 	if err != nil {
 		return nil, fmt.Errorf("%s connect error", ss.addr)
 	}
-	c.(*net.TCPConn).SetKeepAlive(true)
-
+	tcpKeepAlive(c)
 	if err := ss.sharkHand(addr, c); err != nil {
 		return nil, err
 	}
diff --git a/adapters/remote/util.go b/adapters/remote/util.go
index 02c084bc..e8a35006 100644
--- a/adapters/remote/util.go
+++ b/adapters/remote/util.go
@@ -84,3 +84,10 @@ func selectFast(in chan interface{}) chan interface{} {
 
 	return out
 }
+
+func tcpKeepAlive(c net.Conn) {
+	if tcp, ok := c.(*net.TCPConn); ok {
+		tcp.SetKeepAlive(true)
+		tcp.SetKeepAlivePeriod(3 * time.Minute)
+	}
+}