feat(netstack): allow setting gvisor socket options on ForwardTCPIn

coadler · coadler · commit 715bf034c406 · 2023-04-18T15:09:55.000-05:00
diff --git a/wgengine/netstack/netstack.go b/wgengine/netstack/netstack.go
@@ -83,6 +83,9 @@ type Impl struct {
 	// TODO(bradfitz): provide mechanism for tsnet to reject a
 	// port other than accepting it and closing it.
 	ForwardTCPIn func(c net.Conn, port uint16)
+	// ForwardTCPSockOpts, if non-nil, allows setting gvisor socket options on the
+	// created TCPConn before calling ForwardTCPIn.
+	ForwardTCPSockOpts func(port uint16) []tcpip.SettableSocketOption
 
 	// ProcessLocalIPs is whether netstack should handle incoming
 	// traffic directed at the Node.Addresses (local IPs).
@@ -900,7 +903,12 @@ func (ns *Impl) acceptTCP(r *tcp.ForwarderRequest) {
 	}
 
 	if ns.ForwardTCPIn != nil {
-		c := createConn()
+		opts := []tcpip.SettableSocketOption{}
+		if ns.ForwardTCPSockOpts != nil {
+			opts = ns.ForwardTCPSockOpts(reqDetails.LocalPort)
+		}
+
+		c := createConn(opts...)
 		if c == nil {
 			return
 		}
