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To: Dave Taht <dave.taht@gmail.com>, Cake List <cake@lists.bufferbloat.net>
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Date: Sun, 05 Feb 2023 23:17:35 +0100
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Subject: Re: [Cake] flow dissection vs encapsulated traffic?
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Dave Taht via Cake <cake@lists.bufferbloat.net> writes:

> In looking how the code has morphed since I last looked at it, I found
> myself staring at this bit...
>
>         skb_flow_dissect_flow_keys(skb, &keys,
>                                    FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
>
> // so we have delved deeply into the packet at this point... finding
> various encapsulations...
>
> then we get to:
>
>         /* Don't use the SKB hash if we change the lookup keys from conntrack */
>         if (nat_enabled && cake_update_flowkeys(&keys, skb))
>                 use_skbhash = false;
>
> This leverages skb_protocol(), which as best as I can tell just peers
> into the *vlan headers*,
> not deeper into the packet...
>
> Then we proceed merrily into the update_flowkeys code thinking it is
> the outer type
> (ipv4), not the inner, then dissect away, using a v4 union...
>
> Am I reading this wrong? Please tell me I am reading this wrong...

I don't follow. What's the bug you are seeing, specifically?

-Toke