LGTM3 On Wednesday, October 22, 2025 at 8:15:23 AM UTC-7 Chris Harrelson wrote:
> 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. 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/d327a62d-1e64-4246-9eb2-40b5e1cddd04n%40chromium.org.
