add utils.go to socks

proxy/socks/utils.go

@@ -0,0 +1,28 @@
+package socks
+
+import (
+	"net"
+	"time"
+
+	"github.com/xjasonlyu/tun2socks/common/log"
+)
+
+type duplexConn interface {
+	net.Conn
+	CloseRead() error
+	CloseWrite() error
+}
+
+func tcpCloseRead(conn net.Conn) {
+	if c, ok := conn.(duplexConn); ok {
+		log.Warnf("ok!----")
+		c.CloseRead()
+	}
+}
+
+func tcpKeepAlive(conn net.Conn) {
+	if tcp, ok := conn.(*net.TCPConn); ok {
+		tcp.SetKeepAlive(true)
+		tcp.SetKeepAlivePeriod(30 * time.Second)
+	}
+}