Re: [hybi] deflate-stream and masking
"Andy Green (林安廸)" <andy@warmcat.com> Mon, 20 June 2011 08:33 UTC
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Date: Mon, 20 Jun 2011 09:33:47 +0100
From: "\"Andy Green (林安廸)\"" <andy@warmcat.com>
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To: Greg Wilkins <gregw@intalio.com>
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Cc: Hybi <hybi@ietf.org>
Subject: Re: [hybi] deflate-stream and masking
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On 06/20/2011 09:21 AM, Somebody in the thread at some point said: > On 20 June 2011 18:11, "Andy Green (林安廸)"<andy@warmcat.com> wrote: >> On 06/20/2011 07:33 AM, Somebody in the thread at some point said: >> >> Hi - >> >>> As an unmasked WS stream, it was 50675 bytes, and as a masked stream >>> is was 52623 bytes. >>> I then compressed both these streams with gzip and got 13306 bytes for >>> unmasked and 51704 bytes for the masked!!!! >>> >>> So for this very typical example, masking was sufficiently random to >>> completely negate the benefits of compression. >> >> Isn't this just saying that it's dumb to mask-then-compress? >> >> You could just compress-then-mask and get the 13Kbyte result directly and >> "safely". > > That is exactly what I'm saying! > > We should use a deflate-frame extension that does compress-then-mask, > rather than a deflate-stream "extension" that does mask-then-compress. Actually I have to agree with you although I started out intending to just let it lie. For good reasons we changed masking to be payload-only, and added an "I am masked" bit, and subordinated the mask to after the header. All good stuff. So now masking action is strongly defined inside a frame context and won't detach easily to be applied to deflate-stream. Then to fix this the choices are either: 1) add a feature to deflate-stream that it is always masked using a new mask scheme altogether and defeat frame masking if we know the thing has deflate-stream on it 2) just operate deflate-stream on payloads before any per-frame masking gets applied 1) sounds like re-inventing the scary masking wheel. The only little issue with 2) is that deflate-stream operates at bit level, you'll have to spill the bits up to a byte every frame payload. So unless I missed something somewhere, to fix deflate-stream masking bloat it does seem to want delfate-stream action to move to only applying on payloads, and before any masking is done there. -Andy
- [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Andy Green (林安廸)
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Andy Green (林安廸)
- Re: [hybi] deflate-stream and masking Dirkjan Ochtman
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Bob Gezelter
- Re: [hybi] deflate-stream and masking Arman Djusupov
- Re: [hybi] deflate-stream and masking Bruce Atherton
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Andy Green (林安廸)
- Re: [hybi] deflate-stream and masking Ian Fette (イアンフェッティ)
- Re: [hybi] deflate-stream and masking Andy Green (林安廸)
- Re: [hybi] deflate-stream and masking Bruce Atherton
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Brian
- Re: [hybi] deflate-stream and masking Arman Djusupov
- Re: [hybi] deflate-stream and masking Philipp Serafin
- [hybi] Fwd: Re: deflate-stream and masking Justin Lee
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking Alexander Philippou
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking Patrick McManus
- Re: [hybi] deflate-stream and masking Alexander Philippou
- Re: [hybi] deflate-stream and masking Peter Saint-Andre
- Re: [hybi] deflate-stream and masking Gabriel Montenegro
- Re: [hybi] deflate-stream and masking Patrick McManus
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking Willy Tarreau
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking Peter Saint-Andre
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Bjoern Hoehrmann
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Peter Saint-Andre