Vhost net need to know the exact virtio net hdr size to be able
to copy such header correctly. Teach it about the newly defined
UDP tunnel-related option and update the hdr size computation
accordingly.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 drivers/vhost/net.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index b894685dded3e..985f9662a9003 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c

@@ -78,7 +78,9 @@ enum {
 };

 #ifdef VIRTIO_HAS_EXTENDED_FEATURES
-#define VHOST_NET_FEATURES_EX VHOST_NET_FEATURES
+#define VHOST_NET_FEATURES_EX (VHOST_NET_FEATURES | \
+                       (VIRTIO_BIT(VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO)) | \
+                       (VIRTIO_BIT(VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO)))
 #endif

 enum {

@@ -1621,12 +1623,16 @@ static long vhost_net_reset_owner(struct vhost_net *n)
 static int vhost_net_set_features(struct vhost_net *n, virtio_features_t features)
 {
        size_t vhost_hlen, sock_hlen, hdr_len;
+       bool has_tunnel;
        int i;

        hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
                               (1ULL << VIRTIO_F_VERSION_1))) ?
                        sizeof(struct virtio_net_hdr_mrg_rxbuf) :
                        sizeof(struct virtio_net_hdr);
+       has_tunnel = !!(features & (VIRTIO_BIT(VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO) |
+                                   VIRTIO_BIT(VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO)));
+       hdr_len += has_tunnel ? sizeof(struct virtio_net_hdr_tunnel) : 0;