Intent to Prototype: Source Specific Multicast for Direct Sockets API

[Chromestatus]

Contact emails

om...@blockcast.net

Explainer

https://github.com/kkroo/multicast-in-direct-sockets

Specification

https://github.com/WICG/direct-sockets/pull/81

Summary

Adds Source-Specific Multicast (SSM) support to the Direct Sockets API, allowing Isolated Web Apps to optionally specify a source address when joining multicast groups to receive UDP packets only from that source. The Direct Sockets API currently supports Any-Source Multicast (ASM), which receives packets from any source sending to the multicast group. SSM is essential to using multicast outside of private networks, simplifying packet routing, and filtering traffic at the network level by source address, preventing spoofing and denial of service attacks.

Blink component

Blink>Network->Direct Sockets

Web Feature ID

Missing feature

Motivation

RFC 8815 deprecates ASM for inter-domain use due to security vulnerabilities and operational complexity. Without SSM support, developers building multicast applications in Isolated Web Apps face several problems: Limited deployment scenarios: Applications are restricted to controlled private networks where all sources are trusted, preventing use cases like internet-wide content distribution or cross-organization IoT systems. Application-layer filtering overhead: Applications must receive and process all packets sent to a multicast group before validating the source, wasting CPU cycles and bandwidth on potentially malicious traffic. SSM is the standard approach for modern multicast deployments (RFC 4607) and is widely supported by enterprise networks and ISP infrastructure. Adding SSM support enables more secure multicast communication beyond private network boundaries.

Initial public proposal

https://github.com/WICG/direct-sockets/issues/80

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/issues/461262401

Estimated milestones

No milestones specified

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/6208452397498368?gate=5129135169077248

This intent message was generated by Chrome Platform Status.