From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next] vrf: Add ethernet header for pass through VRF
 device
Date: Tue, 25 Aug 2015 14:02:20 -0700 (PDT)
Message-ID: <20150825.140220.156958823239060297.davem@davemloft.net>
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From: David Ahern <dsa@cumulusnetworks.com>
Date: Sun, 23 Aug 2015 12:41:00 -0600

> @@ -250,6 +253,17 @@ static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
>  
>  static netdev_tx_t vrf_finish(struct sock *sk, struct sk_buff *skb)
>  {
> +	int err;
> +
> +	__skb_pull(skb, skb_network_offset(skb));
> +	err = dev_hard_header(skb, skb->dev, ntohs(skb->protocol),
> +			      NULL, NULL, skb->len);
> +
> +	if (err < 0) {
> +		vrf_tx_error(skb->dev, skb);
> +		return -EINVAL;
> +	}
> +
>  	return dev_queue_xmit(skb);

This is expensive and rediculous to do for every TX frame.

You'll need to find another way.