VSOCK: Add virtio vsock vsockmon hooks

The virtio drivers deal with struct virtio_vsock_pkt.  Add
virtio_transport_deliver_tap_pkt(pkt) for handing packets to the
vsockmon device.

We call virtio_transport_deliver_tap_pkt(pkt) from
net/vmw_vsock/virtio_transport.c and drivers/vhost/vsock.c instead of
common code.  This is because the drivers may drop packets before
handing them to common code - we still want to capture them.

Signed-off-by: Gerard Garcia <ggarcia@deic.uab.cat>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/vhost/vsock.c

@@ -176,6 +176,11 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 				restart_tx = true;
 		}
 
+		/* Deliver to monitoring devices all correctly transmitted
+		 * packets.
+		 */
+		virtio_transport_deliver_tap_pkt(pkt);
+
 		virtio_transport_free_pkt(pkt);
 	}
 	if (added)
@@ -383,6 +388,9 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 
 		len = pkt->len;
 
+		/* Deliver to monitoring devices all received packets */
+		virtio_transport_deliver_tap_pkt(pkt);
+
 		/* Only accept correctly addressed packets */
 		if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid)
 			virtio_transport_recv_pkt(pkt);