quic: add experimental ngtcp2 transport#3440
Open
pkorczlab wants to merge 4 commits into
Open
Conversation
Add ngtcp2 as a submodule and expose its static GnuTLS build as the ngtcp2::ngtcp2 CMake target. The CMake wrapper configures ngtcp2 for a library-only build, links libngtcp2 with ngtcp2_crypto_gnutls, and exports the source and generated include directories used by Seastar's QUIC code. Initialize the ngtcp2 submodule in CI before configuring Seastar, and keep the DPDK submodule checkout limited to DPDK-enabled builds. Allow cmake-cooking to delegate project() back to CMake for subprojects that need their own language and project-version setup. Co-authored-by: Adam Karaczewski <adam.karaczewski@gmail.com> Co-authored-by: Kamil Dalidowicz <dalikam748@gmail.com> Co-authored-by: Piotr Korcz <ptrkorcz@gmail.com> Co-authored-by: Stanisław Kalewski <fkalewski@gmail.com>
Add an experimental QUIC API implemented on top of ngtcp2 and GnuTLS. The public interface provides client and server endpoints, connections, bidirectional and unidirectional streams, transport configuration, QUIC errors, and conversion of bidirectional streams to connected_socket. The implementation keeps ngtcp2 and TLS state in per-connection actors. Public stream operations are translated into transport commands for stream creation, data writes, receive credit updates, RESET_STREAM, STOP_SENDING, timers, packet I/O, and connection shutdown. Co-authored-by: Adam Karaczewski <adam.karaczewski@gmail.com> Co-authored-by: Kamil Dalidowicz <dalikam748@gmail.com> Co-authored-by: Piotr Korcz <ptrkorcz@gmail.com> Co-authored-by: Stanisław Kalewski <fkalewski@gmail.com>
Add quic_client_demo and quic_server_demo. The server listens on a UDP address, accepts QUIC connections, accepts streams, and echoes stream data back to the peer. The client connects to the server, opens a stream, forwards stdin to the stream, prints received data, and closes the connection on EOF or SIGINT. The demos cover the application-facing setup for certificate files, endpoint configuration, connection establishment, stream I/O, and shutdown. Co-authored-by: Adam Karaczewski <adam.karaczewski@gmail.com> Co-authored-by: Kamil Dalidowicz <dalikam748@gmail.com> Co-authored-by: Piotr Korcz <ptrkorcz@gmail.com> Co-authored-by: Stanisław Kalewski <fkalewski@gmail.com>
Add unit tests for the experimental QUIC client, server, connection, stream, and transport helper code. The tests cover public object defaults, client/server stream exchange, stream direction handling, accepted-stream delivery, EOF and FIN handling, resets, STOP_SENDING, connected_socket conversion, receive-budget accounting, send backpressure, blocked sends, blocked stream opens, packet receive and drain paths, connection close handling, error classification, and socket address conversion. Co-authored-by: Adam Karaczewski <adam.karaczewski@gmail.com> Co-authored-by: Kamil Dalidowicz <dalikam748@gmail.com> Co-authored-by: Piotr Korcz <ptrkorcz@gmail.com> Co-authored-by: Stanisław Kalewski <fkalewski@gmail.com>
ewienik
reviewed
Jun 2, 2026
Comment on lines
+4
to
+7
|
|
||
| [submodule "ngtcp2"] | ||
| path = ngtcp2 | ||
| url = https://github.com/TusikNusik/ngtcp2 |
There was a problem hiding this comment.
ngtcp2 uses some generic CMake names (ENABLE_STATIC_LIB, ENABLE_SHARED_LIB, etc...) that can collide with seastar CMake names. For this reason there is open PR ngtcp2/ngtcp2#2008. This url points to the PR branch.
The question for maintainers is how to finally maintain this dependency. We could create a fork of ngtcp2 in scylladb organization and put fork the requested change there.
ewienik
reviewed
Jun 2, 2026
Comment on lines
+257
to
+260
| if (Cooking_USE_CMAKE_PROJECT_COMMAND) | ||
| _project (${name} ${ARGN}) | ||
| endif () | ||
|
|
There was a problem hiding this comment.
cmake-cooking overrides CMake's function project with its own macro. Ngtcp2's CMakefile doesn't work with this trick so this is a workaround to cmake-cooking. The question is if it is acceptable.
|
@tchaikov FYI |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Add an experimental QUIC transport backed by ngtcp2 and GnuTLS.
The series adds a bundled ngtcp2 build, exposes an ngtcp2::ngtcp2
CMake target, and initializes the ngtcp2 submodule in CI. The DPDK
submodule checkout remains limited to DPDK-enabled builds.
The new API lives under seastar::quic::experimental and provides
client and server endpoints, connections, bidirectional and
unidirectional streams, transport configuration, QUIC errors, and
conversion of bidirectional streams to connected_socket.
Each connection owns its ngtcp2 and TLS state and drives it from a
single async loop that handles received packets, timer expiry, stream
commands, and connection shutdown.
Also add QUIC client/server demos and unit coverage for the public API,
stream lifecycle, flow control, blocked sends, blocked stream opens,
packet handling, close paths, error classification, and socket address
conversion.