Re: [DNSOP] Clarification question: compression pointers always to names earlier in the packet?

Ray Bellis <ray@bellis.me.uk> Wed, 24 October 2018 15:00 UTC

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From: Ray Bellis <ray@bellis.me.uk>
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Subject: Re: [DNSOP] Clarification question: compression pointers always to names earlier in the packet?
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On 24/10/2018 11:45, Tony Finch wrote:

> There are two basic ways to avoid it:
>
> * Keep a high-water-mark separate from the current location, and require
>   pointers to be strictly less than the HWM. (I prefer this way.)

Right, but to be safe the HWM should be initialised with the position of
the _start_ of the label sequence that's being parsed.

Any time you follow a pointer you reset the HWM to the target of that
pointer (which per the rule above must be lower than the current value).

Ray