netdev - Re: [PATCH net-next 2/3] net/act_pedit: Support using offset relative to the conventional network headers

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Date:   Thu, 01 Dec 2016 14:41:14 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     amir@...ai.me
Cc:     netdev@...r.kernel.org, jhs@...atatu.com, ogerlitz@...lanox.com,
        hadarh@...lanox.com
Subject: Re: [PATCH net-next 2/3] net/act_pedit: Support using offset
 relative to the conventional network headers

From: Amir Vadai <amir@...ai.me>
Date: Wed, 30 Nov 2016 11:09:27 +0200

> @@ -119,18 +119,45 @@ static bool offset_valid(struct sk_buff *skb, int offset)
>  	return true;
>  }
>  
> +static int pedit_skb_hdr_offset(struct sk_buff *skb,
> +				enum pedit_header_type htype, int *hoffset)
> +{
> +	int ret = -1;
> +
> +	switch (htype) {
> +	case PEDIT_HDR_TYPE_ETH:
> +		if (skb_mac_header_was_set(skb)) {
> +			*hoffset = skb_mac_offset(skb);
> +			ret = 0;
> +		}
> +		break;
> +	case PEDIT_HDR_TYPE_RAW:
> +	case PEDIT_HDR_TYPE_IP4:
> +	case PEDIT_HDR_TYPE_IP6:
> +		*hoffset = skb_network_offset(skb);
> +		ret = 0;
> +		break;
> +	case PEDIT_HDR_TYPE_TCP:
> +	case PEDIT_HDR_TYPE_UDP:
> +		if (skb_transport_header_was_set(skb)) {
> +			*hoffset = skb_transport_offset(skb);
> +			ret = 0;
> +		}
> +		break;
> +	};
> +
> +	return ret;
> +}
> +

The only distinction between the cases is "L2", "L3", and "L4".

Therefore I don't see any reason to break it down into IP4 vs. IP6 vs.
RAW, for example.  They all map to the same thing.

So why not just have PEDIT_HDR_TYPE_L2, PEDIT_HDR_TYPE_L3, and
PEDIT_HDR_TYPE_L4?  It definitely seems more straightforward
and cleaner that way.

Thanks.