LGTM2 On Wed, Oct 22, 2025 at 6:16 AM Mike Taylor <[email protected]> wrote:
> LGTM1 > On 10/20/25 4:14 p.m., Reilly Grant wrote: > > IWA OWNER LGTM > > This is an extension to an existing IWA-only feature. Multicast introduces > additional privacy concerns because since content is intended for > consumption by multiple clients it cannot be encrypted in a way which > preserves confidentiality (this has been previously discussed on this list > an network-dev@). Requiring the user to explicitly choose to install an > application rather than making this capability available to any site at > least partially mitigates this concern. > Reilly Grant | Software Engineer | [email protected] | Google Chrome > <https://www.google.com/chrome> > > > On Fri, Oct 17, 2025 at 3:11 AM Chromestatus < > [email protected]> wrote: > >> *Contact emails* >> [email protected] >> >> *Explainer* >> https://github.com/explainers-by-googlers/Multicast-in-Direct-Sockets >> >> *Specification* >> https://github.com/WICG/direct-sockets/pull/79 >> >> *Design docs* >> >> >> https://github.com/WICG/direct-sockets/blob/main/docs/multicast-explainer.md >> >> https://docs.google.com/document/d/1Wna0lkTrhYoTxOO1GjOrut2nWHO19HEyo9YCk39tXqY/edit?usp=sharing >> >> *Summary* >> Allows Isolated Web Apps to subscribe to multicast groups and receive UDP >> packets from there, and to specify additional parameters when sending UDP >> packets to multicasts addresses. >> >> *Blink component* >> Blink>Network->Direct Sockets >> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ENetwork-%3EDirect%20Sockets%22> >> >> *Web Feature ID* >> Missing feature >> >> *Motivation* >> 1. Synchronous video stream from one device to the whole network of >> devices. For example, imagine in a shopping mall there would be multiple >> displays which show videos simultaneously on all devices. 2. Device >> discovery on a local network. mDNS protocol uses multicast sockets under >> the hood. In short, when a device joins a network, it sends a message: >> “Hello, I am headphones-10, my ip is ‘20.20.20.14’ . Who else is here?”, >> other devices reply and in such a manner all devices can know about each >> other without a central server. >> >> *Initial public proposal* >> https://github.com/WICG/proposals/issues/228 >> >> *TAG review* >> Tag does not review Isolated Web Apps. It was stated publicly here >> https://github.com/w3ctag/design-reviews/issues/842#issuecomment-2917031448 >> >> *TAG review status* >> Not applicable >> >> *Risks* >> >> >> *Interoperability and Compatibility* >> Other browsers may choose to implement this API. >> >> *Gecko*: No signal >> >> *WebKit*: No signal >> >> *Web developers*: No signals >> >> *Other signals*: >> >> *Security* >> Security and privacy considerations are explained >> https://github.com/WICG/direct-sockets/blob/main/docs/multicast-explainer.md >> Security considerations This API gives the opportunity to flood the network >> with packets. By only providing this API to Isolated Web Apps the user >> agent can be more confident that the application has not been compromised. >> This allows users and system administrators to confidently grant this >> capability to trusted applications. Additionally, routers have control, >> whether they send multicast packets or drop them. In many setups dropping >> multicast packets is the default setting. >> >> *WebView application risks* >> >> Does this intent deprecate or change behavior of existing APIs, such that >> it has potentially high risk for Android WebView-based applications? >> *No information provided* >> >> >> *Debuggability* >> The code using this API can be debugged using the standard tools. >> Integrating the API with the DevTools Networking tab to enable easier >> introspection of the state of these connections as well as the data >> transferred could be a beneficial future improvement. >> >> *Will this feature be supported on all six Blink platforms (Windows, Mac, >> Linux, ChromeOS, Android, and Android WebView)?* >> No >> This feature is implemented on desktop platforms, although it will only >> be available to the end users on platforms that support Isolated Web Apps, >> which is currently only ChromeOS. Android is excluded for historical >> reasons, although there are no apparent interoperability blockers here. >> >> *Is this feature fully tested by web-platform-tests >> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* >> No >> Cannot be tested in WPT, the issue >> https://github.com/web-platform-tests/wpt/issues/55304 >> >> *DevTrial instructions* >> https://github.com/WICG/direct-sockets/blob/main/docs/multicast-how-to.md >> >> *Flag name on about://flags* >> MulticastInDirectSockets >> >> *Finch feature name* >> MulticastInDirectSockets >> >> *Rollout plan* >> Will ship enabled for all users >> >> *Requires code in //chrome?* >> False >> >> *Measurement* >> Separate programmatic counters for the .idl methods and attributes (via >> MeasureAs) are included to track the stats for API usage: >> MulticastControllerJoinGroupFunction MulticastControllerLeaveGroupFunction >> MulticastControllerJoinedGroupsAttribute >> >> *Availability expectation* >> Feature is available only in Isolated Web Apps on desktop platforms. >> https://chromestatus.com/feature/5146307550248960 >> >> *Adoption expectation* >> Expected to be used initially by a small number of developers inside >> Isolated Web Apps. >> >> *Adoption plan* >> Working directly with developers that are planning to rely on the API. >> >> *Estimated milestones* >> Shipping on desktop 144 >> DevTrial on desktop 142 >> >> *Anticipated spec changes* >> >> Open questions about a feature may be a source of future web compat or >> interop issues. Please list open issues (e.g. links to known github issues >> in the project for the feature specification) whose resolution may >> introduce web compat/interop risk (e.g., changing to naming or structure of >> the API in a non-backward-compatible way). >> None >> >> *Link to entry on the Chrome Platform Status* >> https://chromestatus.com/feature/5073740211814400?gate=5084202819256320 >> >> *Links to previous Intent discussions* >> Intent to Prototype: >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/68aeedee.050a0220.27f047.019b.GAE%40google.com >> >> >> This intent message was generated by Chrome Platform Status >> <https://chromestatus.com>. >> -- >> 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 visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/68f21631.050a0220.29f70d.0062.GAE%40google.com >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/68f21631.050a0220.29f70d.0062.GAE%40google.com?utm_medium=email&utm_source=footer> >> . >> > -- > 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 visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAEmk%3DMZTErruSN4dM%2Bx00tOVDQtBxEESqd8HWmWYKaG7nYm9vg%40mail.gmail.com > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAEmk%3DMZTErruSN4dM%2Bx00tOVDQtBxEESqd8HWmWYKaG7nYm9vg%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- > 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 visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/2ac595c1-3ac2-4a79-87f5-54ca3ac1bd44%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/2ac595c1-3ac2-4a79-87f5-54ca3ac1bd44%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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