vxlan: Only set has-GBP bit in header if any other bits would be set

This allows for a VXLAN-GBP socket to talk to a Linux VXLAN socket by
not setting any of the bits.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index c184717e8b28..d08072c10aa9 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1667,6 +1667,9 @@ static void vxlan_build_gbp_hdr(struct vxlanhdr *vxh, u32 vxflags,
 {
         struct vxlanhdr_gbp *gbp;
 
+        if (!md->gbp)
+                return;
+
         gbp = (struct vxlanhdr_gbp *)vxh;
         vxh->vx_flags |= htonl(VXLAN_HF_GBP);