Thanks for clarifying. Last question: where in the specifications is the new 17613 code point documented?
On Fri, Jan 19, 2024 at 12:59 PM Mike Taylor <[email protected]> wrote: > In our OWNERS meeting this week, there was some confusion on what's being > proposed here (which is understandable, this isn't quite a typical intent > for web exposed feature). Here's a summary of what we're trying to > accomplish: > > 1) We shipped support for the ACCEPT_CH frame over h2 and h3 back in M96, > which relies on the TLS ALPS protocol extension. > 2) There are 2 parts to this: the client being able to understand > ALPS/ACCEPT_CH (and in return do something useful), and the server being > able to send it. > 3) Because of a (long fixed) bug present in Chromium's implementation, > it's risky for a server to send too much data via ACCEPT_CH, so it's > usefulness is potentially limited. > 4) In order to guarantee that older clients don't have this bug, we > propose to rev the version (aka, code point) at the protocol layer. This > way, if a server sends the new code point and the client understands it, it > can send a larger payload without triggering the bug (which may result in > sad things like a connection being refused). > 5) This is sort of web observable, but right now if servers that support > the old code point continue to send the old code point - nothing will > break. Chromium will support both for now, with hopes to deprecate and > remove the older one in the future when we're confident it won't result in > performance regressions for servers sending ACCEPT_CH (since this is a > performance optimization). > > I hope that helps clear it up, and I'm sure Victor or David will chime in > if I'm getting something wrong. :) > > And to be clear - this isn't a request for a deprecation or removal (yet), > but for shipping the new code point. > On 1/17/24 11:16 AM, Victor Tan wrote: > > If the server received the new code point, while it doesn't support, the > ALPS extension will ignore. This also mean client might not know the > server's client hints preferences before the first request. Currently, only > few sites using the ALPS extension. As TLS extension is negotiated, the > server need to support both code points during the transition period, after > some time, the server can drop the old one. > > On Wednesday, January 17, 2024 at 11:00:13 AM UTC-5 Yoav Weiss wrote: > >> On Saturday, January 13, 2024 at 12:08:33 AM UTC+1 Victor Tan wrote: >> >> Contact emails >> >> [email protected], [email protected], [email protected] >> >> Explainer >> >> https://github.com/WICG/client-hints-infrastructure/ >> blob/main/reliability.md >> >> Specification >> >> https://tools.ietf.org/html/draft-davidben-http-client-hint-reliability >> >> https://tools.ietf.org/html/draft-vvv-httpbis-alps >> >> https://tools.ietf.org/html/draft-vvv-tls-alps >> >> >> Summary >> >> Shipping a new code point (17613) for TLS ALPS extension to allow adding >> more data in the ACCEPT_CH HTTP/2 and HTTP/3 frame. The ACCEPT_CH HTTP/2 >> frame with the existing TLS ALPS extension code point (17513) had an >> arithmetic overflow bug <https://crbug.com/1292069> in the Chrome ALPS >> decoder. It limits the capability to add more than 128 bytes data (in >> theory, the problem range is 128 bytes to 255 bytes) to the ACCEPT_CH >> frame. With the new ALPS code point, we can fully mitigate the issue. >> >> Blink component >> >> Blink>Network>ClientHints >> <https://bugs.chromium.org/p/chromium/issues/list?q=component%3ABlink%3ENetwork%3EClientHints%2C&can=2> >> >> TAG review >> >> https://github.com/w3ctag/design-reviews/issues/549 >> >> TAG review status >> >> Closed >> >> Risks >> Interoperability and Compatibility >> >> This is switching to a new code point for the TLS ALPS extension. It >> won’t change the design of ALPS and ACCEPT_CH mechanism implementation. >> The main source of compatibility risk is that it causes conflicts with ALPS >> negotiation since some clients could still use the old code point while >> others are switching to use the new code point. The ALPS extension could >> be ignored if the code point doesn’t match during negotiation, which means >> the server's client hints preferences won’t be delivered in the ACCEPT_CH >> HTTP/2 and HTTP/3 frame. We mitigate this by enabling servers to support >> both code points, monitoring both code points usage and removing the old >> ALPS code point support in a future intent once the usage is low enough. We >> also split the rollout into two phases: we first start to enable the new >> ALPS code point for ACCEPT_CH with HTTP/3 frame in a slow rollout, and >> then eventually enable the new code point with HTTP/2 frame. >> >> >> Does the server have an indication if the client in question supports the >> newer code point? >> If not, what would we expect servers that support the newer code point to >> do? >> >> >> >> >> Edge: No signals >> >> Firefox: Pending https://github.com/mozilla/ >> standards-positions/issues/510 >> Safari: Pending https://lists.webkit.org/pipermail/webkit-dev/2021- >> April/031768.html >> >> Web/Framework developers: https://twitter.com/Sawtaytoes/status/ >> 1369031447940526080 https://twitter.com/_jayphelps/status/ >> 1369023028735148032 >> >> Activation >> >> The site’s TLS and HTTP serving application would need to be updated to >> support this new code point. We aren’t aware of many sites using this >> feature yet, however. >> >> Debuggability >> >> No special DevTools support needed. The effects of the code point change >> of ACCEPT_CH frame will be visible in the DevTools’ network tab. Also, the >> NetLog will record the ACCEPT_CH frame value if TLS ALPS extension is >> negotiated successfully. >> >> Will this feature be supported on all six Blink platforms (Windows, Mac, >> Linux, Chrome OS, Android, and Android WebView)? >> >> Yes >> >> Is this feature fully tested by web-platform-tests >> <https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md> >> ? >> >> No, this feature is tested with browser-side tests. We can’t test >> TLS-adjacent features currently through web-platform-tests. See this issue: >> https://github.com/web-platform-tests/wpt/issues/20159 >> >> Flag name >> >> UseNewAlpsCodepointHttp2 >> >> UseNewAlpsCodepointQUIC >> >> Tracking bug >> >> b/289087287 >> >> Launch bug >> >> https://launch.corp.google.com/launch/4299022 >> >> Link to entry on the Chrome Platform Status >> https://chromestatus.com/feature/5149147365900288 >> >> -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/c704d985-a5cc-4e5e-99b0-1f78cc4428e6%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/c704d985-a5cc-4e5e-99b0-1f78cc4428e6%40chromium.org?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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