From 241d179eba0fba0d180926123b9de15b48e46cbe Mon Sep 17 00:00:00 2001
From: "Zvi \"CtrlZvi\" Effron" <viz+GitHub@flippedperspective.com>
Date: Sat, 2 Sep 2017 20:24:57 +0000
Subject: [PATCH] Fix failing XDP test

On newer linux kernels (4.12), netlink rejects a request to set an XDP
program with flags set to 0. Instead, flags need to not be specified if they
are 0.
---
 link_linux.go | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/link_linux.go b/link_linux.go
index 5bdff5f..ed35c0d 100644
--- a/link_linux.go
+++ b/link_linux.go
@@ -1811,8 +1811,10 @@ func addXdpAttrs(xdp *LinkXdp, req *nl.NetlinkRequest) {
 	b := make([]byte, 4)
 	native.PutUint32(b, uint32(xdp.Fd))
 	nl.NewRtAttrChild(attrs, nl.IFLA_XDP_FD, b)
-	native.PutUint32(b, xdp.Flags)
-	nl.NewRtAttrChild(attrs, nl.IFLA_XDP_FLAGS, b)
+	if xdp.Flags != 0 {
+		native.PutUint32(b, xdp.Flags)
+		nl.NewRtAttrChild(attrs, nl.IFLA_XDP_FLAGS, b)
+	}
 	req.AddData(attrs)
 }