Add OpenVPN, TrustTunnel, Sudoku, inbound managers. Fixes

common/onclose/conn.go

@@ -0,0 +1,38 @@
+package onclose
+
+import (
+	"net"
+	"sync"
+)
+
+type CloseHandlerFunc = func()
+
+type Conn struct {
+	net.Conn
+	onClose func()
+	once    sync.Once
+}
+
+func NewConn(conn net.Conn, onClose func()) *Conn {
+	return &Conn{Conn: conn, onClose: onClose}
+}
+
+func (c *Conn) Close() error {
+	c.once.Do(c.onClose)
+	return c.Conn.Close()
+}
+
+type PacketConn struct {
+	net.PacketConn
+	onClose func()
+	once    sync.Once
+}
+
+func NewPacketConn(conn net.PacketConn, onClose func()) *PacketConn {
+	return &PacketConn{PacketConn: conn, onClose: onClose}
+}
+
+func (c *PacketConn) Close() error {
+	c.once.Do(c.onClose)
+	return c.PacketConn.Close()
+}