Refactor QUIC version downgrade prevention

This CL is the start of a series of CLs aimed at supporting draft-ietf-quic-version-negotiation. This CL refactors the Google QUIC version downgrade prevention transport parameter to better indicate that it is optional. This will make it easier to implement the IETF replacement and run both together during the transition period. This CL does not change any behavior, and is therefore not flag protected.

PiperOrigin-RevId: 408700446
5 files changed
tree: 07c007e082173c32791baea372f5d5723768ce65
  1. common/
  2. epoll_server/
  3. http2/
  4. quic/
  5. spdy/


QUICHE stands for QUIC, Http/2, Etc. It is Google‘s production-ready implementation of QUIC, HTTP/2, HTTP/3, and related protocols and tools. It powers Google’s servers, Chromium, Envoy, and other projects. It is actively developed and maintained.

There are two public QUICHE repositories. Either one may be used by embedders, as they are automatically kept in sync:

To embed QUICHE in your project, platform APIs need to be implemented and build files need to be created. Note that it is on the QUICHE team's roadmap to include default implementation for all platform APIs and to open-source build files. In the meanwhile, take a look at open source embedders like Chromium and Envoy to get started:

To contribute to QUICHE, follow instructions at

QUICHE is only supported on little-endian platforms.