socket option PACKET_VNET_HDR usage

Hi, All

What's the usage scenario of PACKET_VNET_HDR option?

I noticed the author of its owner tried use it in a qemu patch below:
but it didn't seems to be merged after I quick search current qemu tree.
Is there any other user land application to make use of this option?

https://www.mail-archive.com/kvm@vger.kernel.org/msg27833.html


Thanks