Re: Proposal: New Frame Size Text (was: Re: Design Issue: Frame Size Items)
James M Snell <jasnell@gmail.com> Sat, 11 May 2013 17:24 UTC
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From: James M Snell <jasnell@gmail.com>
Date: Sat, 11 May 2013 10:21:36 -0700
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To: Roberto Peon <grmocg@gmail.com>
Cc: Martin Thomson <martin.thomson@gmail.com>, "William Chan (陈智昌)" <willchan@chromium.org>, Poul-Henning Kamp <phk@phk.freebsd.dk>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>, Hasan Khalil <hkhalil@google.com>
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Subject: Re: Proposal: New Frame Size Text (was: Re: Design Issue: Frame Size Items)
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I generally find it safer not to make any assumptions here about what any given random implementation will or will not do. The best we can do is provide some degree of protection against abuse in the protocol definition itself. It doesn't have to be perfect, by any means, but it does have to be somewhat reasonable. I'm perfectly fine with not including HEADERS/PUSH_PROMISE in flow control but we ought to at least place limits on exactly how much data is being passed in those frames at any given time -- precisely because we don't know exactly how those are going to end up being used long term and we do not want to inadvertently encourage abuse. If you want a sender to still be able to send HEADERS frames even if the window size is 0 (or lower than we can reasonably encode a minimal header block), then a compromise here is pretty simple: For data frames, max frame size is min(WINDOW_SIZE, 65k) ... For control frames (including HEADERS), max frame size is max(4k, min(WINDOW_SIZE, 65k)) ... This ought to give us a reasonable range to work within. It basically just states that while control frames are not subject to flow control, when constructing headers frames, the sender needs to take into consideration whatever load the recipient may currently be experiencing as expressed through flow control. On Fri, May 10, 2013 at 8:15 PM, Roberto Peon <grmocg@gmail.com> wrote: > For implementations that don't care about memory efficiency, you're right > that they'll unencode the huffman-encoded strings. :) > > The majority of non-efficiency-oriented APIs I've used treated the overhead > of HTTP and IO as insignificant, and likely just wouldn't care about this at > all. > -=R > > > On Fri, May 10, 2013 at 8:01 PM, Martin Thomson <martin.thomson@gmail.com> > wrote: >> >> On 10 May 2013 18:30, Roberto Peon <grmocg@gmail.com> wrote: >> > The memory needed for header interpretation will, for a decent >> > implementation, be at worst the sum of the size of the compression >> > context >> > and the size of the receive buffer-- it will not expand once >> > decompressed >> > unless a lot of useless copying is being done. >> >> I was going to say the same thing until I realized that most APIs will >> be forced to decode Huffman-encoded strings to present. Some >> implementations might avoid this entirely, others might defer >> decompression, or something along those lines, but there is probably >> going to be at least some exposure to the decompressed data. > >
- Proposal: New Frame Size Text (was: Re: Design Is… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… William Chan (陈智昌)
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… Roberto Peon
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… William Chan (陈智昌)
- Re: Proposal: New Frame Size Text (was: Re: Desig… Martin Thomson
- Re: Proposal: New Frame Size Text (was: Re: Desig… Martin Thomson
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… Martin Thomson
- Re: Proposal: New Frame Size Text (was: Re: Desig… William Chan (陈智昌)
- Re: Proposal: New Frame Size Text (was: Re: Desig… William Chan (陈智昌)
- Re: Proposal: New Frame Size Text (was: Re: Desig… Poul-Henning Kamp
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… Roberto Peon
- Re: Proposal: New Frame Size Text (was: Re: Desig… William Chan (陈智昌)
- Re: Proposal: New Frame Size Text (was: Re: Desig… Roberto Peon
- Re: Proposal: New Frame Size Text (was: Re: Desig… Poul-Henning Kamp
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text Martin J. Dürst
- Re: Proposal: New Frame Size Text (was: Re: Desig… Roberto Peon
- Re: Proposal: New Frame Size Text (was: Re: Desig… Martin Thomson
- Re: Proposal: New Frame Size Text (was: Re: Desig… Roberto Peon
- Re: Proposal: New Frame Size Text Poul-Henning Kamp
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… William Chan (陈智昌)
- Re: Proposal: New Frame Size Text (was: Re: Desig… Ben Niven-Jenkins
- Re: Proposal: New Frame Size Text (was: Re: Desig… Poul-Henning Kamp
- Re: Proposal: New Frame Size Text (was: Re: Desig… William Chan (陈智昌)
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… Poul-Henning Kamp
- Re: Proposal: New Frame Size Text (was: Re: Desig… Martin Thomson
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… James M Snell
- Re: Proposal: New Frame Size Text (was: Re: Desig… Patrick McManus