net: fix TAP networking on host kernels without IFF_VNET_HDR support

vnet_hdr is initialized at 1 by default. We need to reset it to 0 if
the kernel doesn't support IFF_VNET_HDR.

Signed-off-by: Pierre Riteau <Pierre.Riteau@irisa.fr>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/net/tap-linux.c b/net/tap-linux.c
index 0f621a2315d323ffde277cc2eda483118d7b3567..e4f7e2723b76bff4b16512bd1dcedf2dc66656c5 100644 (file)
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -52,6 +52,8 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required
             features & IFF_VNET_HDR) {
             *vnet_hdr = 1;
             ifr.ifr_flags |= IFF_VNET_HDR;
+        } else {
+            *vnet_hdr = 0;
         }
 
         if (vnet_hdr_required && !*vnet_hdr) {