v0.41.0

New Features

• When calling quic.Connection.SendDatagram, we now queue up to 32 DATAGRAMs before blocking this method: #4222. This should lead to significant performance improvements for applications that send a lot of datagrams.
• DATAGRAM frames that don't fit into a packet (at the current MTU) are now dropped: #4221.
• http3: The remote address (as a net.Addr) can now be obtained from the HTTP/3 request context using the http3.RemoteAddrContextKey: #4208. Thanks to @oncilla!
• http3: When an http.Handler panics, the stream is now reset: #4181. Thanks to @WeidiDeng!
• http3: The http3.Server now has a ConnContext function, working analogously to http.Server.ConnContext: #4230. Thanks to @rthellend!
• logging: Information about the negotiated ALPN is logged using logging.ConnectionTracer.ChoseALPN: #4216. Thanks to @birneee!
• qlog: The package now provides an implementation of the quic.Config.ConnectionTracer callback that reads the QLOGDIR environment variable, and writes qlogs to that directory. Thanks to @birneee!

Breaking Changes

• This release drops support for Go 1.20 (#4195). We decided to support the old Go version a little bit earlier than usual (before the Go 1.22 release) this time, since this allowed us to completely remove our custom TLS fork that was necessary before crypto/tls gained QUIC support in Go 1.21. If you rely on Go 1.20, you can continue using the v0.40.1 release.
• The DroppedPacket callback on the logging.ConnectionTracer now contains the packet number of the dropped packet, allowing for better logging of duplicate packets: #4171

Other Changes

• Only attempt 0-RTT resumption if the session-ticket allowed 0-RTT: #4183
• http3: The context cancelation error is now returned from RoundTrip: #4203
• http3: use the AdditionalSettings for on HTTP/3 requests: #4156

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Changelog

• congestion: don't use floating point math when calculating pacing times by @marten-seemann in #4148
• don't set the TLS version in the transport by @marten-seemann in #4135
• ackhandler: immediately acknowledge ECN-CE marked packets by @marten-seemann in #4147
• README: fix typo by @anderspitman in #4166
• fix flaky server test by @marten-seemann in #4167
• fix serialization of connection ID in filenames of qlog files by @marten-seemann in #4170
• logging: pass the packet number to ConnectionTracer.DroppedPacket by @marten-seemann in #4171
• interop: update Go version to 1.21.4 by @marten-seemann in #4179
• wire: reject NEW_CONNECTION_ID frames with zero-length conneciton IDs by @marten-seemann in #4180
• send large max_datagram_frame size, introduce a DatagramTooLargeError error by @chungthuang in #4143
• fuzzing: add transport parameter validation logic by @marten-seemann in #4175
• reduce calls to time.Now() calls in connection by @birneee in #4191
• http3: use the AdditionalSettings for requests by @marten-seemann in #4156
• README: add gost project by @char8x in #4154
• qtls: only attempt 0-RTT resumption for 0-RTT enabled session tickets by @marten-seemann in #4183
• examples: close listener, connection and stream in echo client and server by @rfyiamcool in #4188
• fuzzing: update Go version to 1.21 by @marten-seemann in #4192
• integrationtests: remove leftover code for Go 1.19 by @marten-seemann in #4193
• limit the number of queued PATH_RESPONSE frames to 256 by @marten-seemann in #4199
• don't retransmit PATH_CHALLENGE and PATH_RESPONSE frames by @marten-seemann in #4200
• ci: update golangci-lint to v1.55.2 by @marten-seemann in #4204
• fuzzing: add frame field validation logic by @marten-seemann in #4206
• http3: add remote address to request context by @oncilla in #4208
• http3: reset stream when a handler panics by @WeidiDeng in #4181
• http3: don't use error string as a format string by @nanokatze in #4211
• http3: improve debug message when determining the listener port fails by @nanokatze in #4214
• http3: return the context cancellation error from RoundTrip by @marten-seemann in #4203
• qlog: add support for alpn_information event by @birneee in #4216
• drop support for Go 1.20, build on Go 1.22rc1 by @marten-seemann in #4195
• utils: use time.Duration.Abs by @marten-seemann in #4217
• utils: switch to builtin min and max funtions by @marten-seemann in #4218
• http3: fix channel size in ListenAndServe by @narqo in #4219
• qtls: remove unneeded type alias for the tls.QUICEncryptionLevel by @marten-seemann in #4220
• discard DATAGRAM frames that don't fit into packets without an ACK by @marten-seemann in #4221
• queue up to 32 DATAGRAM frames to send by @marten-seemann in #4222
• use a ring buffer for the datagram queue by @marten-seemann in #4223
• handshake: remove unneeded mutex in cryptoSetup by @marten-seemann in #4227
• README: add RoadRunner to list of projects by @marten-seemann in #4226
• wire: use netip.AddrPort in the Preferred Address transport parameter by @marten-seemann in #4232
• ackhandler: refactor ACK queueing logic by @marten-seemann in #4225
• fix race condition when dropping Initial packet with short connection ID by @marten-seemann in #4236
• http3: add ConnContext to the server by @rthellend in #4230
• example: add config flag for TLS key and cert for the server by @marten-seemann in #4237
• wire: improve logging of connection ID retirements by @marten-seemann in #4241
• qlog: add a default tracer that writes to QLOGDIR by @birneee in #4233
• example: remove -v flag and custom logger configuration by @marten-seemann in #4242
• example: remove -qlog flag in favor of QLOGDIR by @marten-seemann in #4243
• http3: add a basic README by @marten-seemann in #4246

New Contributors

• @anderspitman made their first contribution in #4166
• @chungthuang made their first contribution in #4143
• @char8x made their first contribution in #4154
• @rfyiamcool made their first contribution in #4188
• @oncilla made their first contribution in #4208
• @nanokatze made their first contribution in #4211
• @narqo made their first contribution in #4219
• @rthellend made their first contribution in #4230

Full Changelog: v0.40.0...v0.41.0