From 3a8cfbc381869d3b4590da84185783f60db5a993 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Sat, 24 Aug 2024 18:04:58 -0700
Subject: [PATCH] tstest/natlab: be more paranoid about IP versions from gvisor

I didn't actually see this, but added this while debugging something
and figured it'd be good to keep.

Updates #13038

Change-Id: I67934c8a329e0233f79c3b08516fd6bad6bfe22a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
---
 tstest/natlab/vnet/vnet.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tstest/natlab/vnet/vnet.go b/tstest/natlab/vnet/vnet.go
index b23bf4342..cecf49942 100644
--- a/tstest/natlab/vnet/vnet.go
+++ b/tstest/natlab/vnet/vnet.go
@@ -234,7 +234,7 @@ func (n *network) handleIPPacketFromGvisor(ipRaw []byte) {
 			ipRaw,
 			layers.LayerTypeIPv6, gopacket.Lazy)
 	default:
-		return
+		panic(fmt.Sprintf("unexpected IP packet version %v", ipVer))
 	}
 	flow, ok := flow(goPkt)
 	if !ok {