Release 3.1.1

Release 3.1.0

Release 3.0.4

update boringssl version info to support h3 (#346)

* update boringssl version info to support h3

RFC9001: QUIC transport parameters are carried in a TLS extension.
Different versions of QUIC might define a different method for negotiating transport configuration.

h3: quic_transport_parameters(0x39)

* Fix comments about support draft verions

Release 3.0.3

Release 3.0.2

Release 3.0.1

Release 3.0.0

Release 2.30.2

Release 2.30.1

Release 2.30.0

- [FEATURE] Added support for sending/receiving multiple headers to address the
case related to "100 continue" header handling.
- [BUGFIX] Addressed high CPU usage for a GOAWAY connection before sending
CONNECTION_CLOSE.
- [BUGFIX] Addressed SIGFPE due to zero pacing rate. (ISSUE #254).
- [BUGFIX] Fixed a minor issue related to multi-paths.

Release 2.29.6

- Documentation: describe lsquic internals ("guts").
- Two more fixes to compliance issues found by h3spec.
- Truncate, don't abort, SCIDs larger than 16 bytes (PR #244).
- Several small internal improvements and space optimizations.

Release 2.29.5

- Fix a few issues detected by h3spec for better compliance with HTTP/3 standard.

Release 2.29.4

- [BUGFIX] Infinite loop in stream: returned HQ frame can be at any
point on the list.
- [BUGFIX] Fail push promise immediately if STREAM_NOPUSH is set.

Release 2.29.3

- [BUGFIX] Do not send RESET_STREAM if writing to stream is already
finished.
- perf_client: wait for all ACKs before exiting.
- Improve how generated RESET_STREAM is logged.
- Fix compilation in different combos of adv_tick/conn_stats flags.
- Move qpack warning disablement into src/liblsquic/CMakeLists.txt.

Release 2.29.2

- Fix regression in gQUIC server: bug #234.

Release 2.29.1

- Make it possible to build the library and unit tests without
libevent.
- Build all command-line utilities in bin/
- Add perf_client and perf_server command-line utilities to test
performance according to the "perf" protocol.

Release 2.29.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 34 support and v1 support.
The latter is turned off by default.
- Drop support for ID-28 and ID-32.
- [BUGFIX] IETF QUIC mini conn receive history (trechist): allow
unlimited inserts by dropping smallest elements.
- [BUGFIX] gQUIC: set STTL to correct value, issue #226.
- [BUGFIX] Account for poison packet gap when MTU probe was too large.

Release 2.28.0

- [API] lsquic_ssl_sess_to_resume_info() is the new way to get
session info.
- [API] Add user pointer to ea_generate_scid callback.
- [API] Add lsquic_dcid_from_packet() -- a fast function to parse
out DCID.
- [API] Add es_max_batch_size to control outgoing packet batch size.
- [BUGFIX] Disallow sending of header while promise is being written.
- [BUGFIX] Flush stream when buffered bytes exhaust stream cap.
- [BUGFIX] Deactivate HQ frame if writing push promise fails.
- Perform sanity check on peer transport parameters and fail the
handshake if some flow control limits are too low. This can be
turned off, see es_check_tp_sanity.
- http_server: fix how requests are read in "hq" mode.

Release 2.27.6

- [BUGFIX] Replace dispatch read/write events assertion with a check.
- [BUGFIX] gQUIC connection close: there is no HEADERS stream without
HTTP flag, see issue #220.
- http_client, http_server: add hq protocol support and other flags
for use with QUIC Interop Runner.
- Fix: use IP_PMTUDISC_PROBE (not IP_PMTUDISC_DO) on Linux to set
Don't-Fragment flag on outgoing packets.
- Fix send_packets_one_by_one on Windows platform when sending
multiple iovs, see issue #218.
- Exit echo_client on Windows immediately, see issue #219.

Release 2.27.5

- [BUGFIX] Assertion in send controller when path validation fails.
- [BUGFIX] Assertion in BBR when sending out-of-order packets is
detected.
- [BUGFIX] Drop overflow receive history ranges when cloning.
- Log correct size of the incoming packet.
- Fix internal stream function.

Release 2.27.4

- [API] Add lsquic_conn_get_sni(), fixes issue #203.

API: add lsquic_conn_get_sni(), fixes issue #203

Release 2.27.3

- [BUGFIX] gQUIC: do not destroy critical streams when connection is
closed. See issue #201.
- [BUGFIX] Drop #if LSQUIC_CONN_STATS from lsquic.h. See issue #211.
- [BUGFIX] Challenge cancellation when path validation fails.
- [BUGFIX] Do not send FIN if RST is scheduled to be sent on a stream.
- [BUGFIX] gQUIC's is_tickable() when connection is closing.
- [BUGFIX] Q050 processing of GOAWAY frames.

Release 2.27.2

- [BUGFIX] Memory corruption in receive history copy-ranges function.

Release 2.27.1

- [API] New knob to set outgoing packet batch size.
- Aborted connection now become tickable immediately.
- Abort connection when HTTP/3 frame cannot be opened (can only happen
when malloc fails).

Release 2.27.0

- [API] Remove keylog callbacks. See issue #188.
- Add a bit more ALPN logging.

Release 2.26.2

- [BUGFIX] Do not drop incoming data when STOP_SENDING is received.
- [BUGFIX] Receipt of STOP_SENDING should not cause read-reset.
- [BUGFIX] Allow stream writes after receiving RESET.
- [BUGFIX] Typo in stream: ANDing enum with wrong flag.
- [BUGFIX] Reset elision: do not use zero as special stream ID value,
for zero is a valid stream ID in IETF QUIC.
- [API] Add optional on_conncloseframe_received() callback.
- Use zero error code in RESET stream sent in response to STOP_SENDING.

Removed #define LSQUIC_SUPPORTS_CONNCLOSEFRAME_CALLBACK

See discussion in PR #205

Support new lsquic_stream_if callback on_conncloseframe_received() to notify application of CONNECTION_CLOSE frame

Release 2.26.1

- [BUGFIX] Migration corner cases: drop or pad over path challenge
and response frames when necessary.
- Fix stream unit test.

Release 2.26.0

- [OPTIMIZATION] Adjust packet reordering threshold when spurious losses
are detected.
- [API] Pass pointer to local sockaddr to ea_get_ssl_ctx() callback.

Release 2.25.0

- [API, FEATURE] Add es_delay_onclose option to delay on_close until all
data is ACKed. Use new function lsquic_stream_has_unacked_data() to
learn whether peer acknowledged all data written to stream.
- [API] Add optional on_reset() stream callback to get notifications
when RESET or STOP_SENDING frames are received.
- [BUGFIX] On STOP_SENDING, make conn tickable is _writeable_, not
readable.

Release 2.24.5

- [FEATURE] Improve Delayed ACKs extension and turn it on by default.
- Limit receive history to a finite amount of memory.

Release 2.24.4

- [BUGFIX] Check whether ECN counts are set in ACK struct before using them.
- [BUGFIX] Calculate TLP timer correctly when only one packet is in flight.
- [BUGFIX] Min RTO delay is 200 milliseconds, not 1 second.
- [BUGFIX] Memory leak in QPACK decoder handler: discard hset when necessary.
- Allow retired and drained CIDs to be reused after a timeout.

Release 2.24.3

- [BUGFIX] Get rough RTT estimate on receipt of Handshake packet.
This prevents BBR on the client from miscalculating pacing rate,
slowing down sending of ACK packets.
- [BUGFIX] Packets sent during handshake are app-limited.
- [BUGFIX] Bandwidth sampler starts in app-limited mode.
- [BUGFIX] Memory leak: free QPACK handler context in stream dtor.
- Logging improvements.

Release 2.24.2

- [BUGFIX] Allow peer to migrate when its SCID is zero-length.
- [BUGFIX] PADDING size calculation: only one Short packet can be
coalesced. (This should have been part of the fix in 2.24.1).
- Abort connect if received NEW_CONNECTION_ID but current DCID is
zero-length.
- Improve log messages

Release 2.24.1

- [API] Allow use of ea_get_ssl_ctx() on the client (optional). PR #186.
- [BUGFIX] Expand datagram with ack-eliciting Initial to 1200 bytes
after connection promotion.
- [BUGFIX] Discard CRYPTO frames from lower encryption levels after
connection promotion.
- [BUGFIX] Cancel path response if path could not be initialized.

Keep ea_get_ssl_ctx() optional for the client

Release 2.24.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 31 support. Drop ID-30
and ID-31 support.
- [BUGFIX] Divide-by-zero in newly enabled conn stats code when no
packets were sent.
- [BUGFIX] Memory leak in gQUIC client when server hello cannot be
parsed.
- [BUGFIX] Server Initial packet size calculation.
- Log user-agent and CONN_CLOSE reason when peer reports error.
- Example programs: Specify ALPN for echo and md5 clients and servers
(issue #184).
- Example programs: Don't add "QUIC_" prefix to lines in keylog file
(issue #185).
- http_server: Fix fd leak in preadv mode; fix preadv() usage when
reading from disk.

Release 2.23.3

- [BUGFIX] Update packetization threshold when writing to stream
after packet size is reduced following an RTO.

Release 2.23.2

- Add QPACK stats collection and experimentation mode, see the new
es_qpack_experiment setting.
- Log busy connection stats every second using the new "conn-stats"
log module.
- Log about skipping only once.
- Update HTTP/3 greased frame type formula.
- Use ls-qpack v2.2.1.

Release 2.23.1

- [BUGFIX] Regression introduced in 2.22.0: use correct number of
PNSs for IETF mini conn during promotion.

Release 2.23.0

- [FEATURE] IETF Client 0-RTT support.
- [BUGFIX] Do not schedule MTU probe on first tick.
- [BUGFIX] Parsing DATAGRAM frame.
- [BUGFIX] If push promise fails, do not invoke hset destructor.
- [BUGFIX] Client: When connections are IDed by port number, check DCID.
Fixes issue #176.
- Revert the 2.22.1 lsquic_is_valid_hs_packet change. All that was
necessary is a change to the way we call it in lsquic_engine. No
change to the function itself is required.

Release 2.22.1

- [BUGFIX] Function that checks validity of handshake packets.

Release 2.22.0

- [FEATURE] Extensible HTTP Priorities (HTTP/3 only).
- [FEATURE] Add conn context to packet-out memory interface (PR #175).
- [BUGFIX] gQUIC proof generation: allocate buffer big enough for
signature (issue #173).
- [BUGFIX] Make library thread-safe: drop use of global variables
(issue #133, issue #167).
- [BUGFIX] Deactivate only *recent* HQ frame, not any HQ frame.
- [BUGFIX] gQUIC server: associate compressed cert with SSL_CTX,
instead of keeping them in a separate hash, potentially leading
to mismatches.
- [BUGFIX] Stream data discard infinite loop: break on FIN.
- cmake: add install target via -DCMAKE_INSTALL_PREFIX (PR #171).
- Support randomized packet number to begin a connection.
- Mini and full IETF connection size optimization.
- http_client: specify HTTP priorities based on stream conditions.

GSO-Friendly Packet Memory (#175)

Release 2.21.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 31 support.
- [API] Let user generate Souce Connection IDs.
- [FEATURE] Allow building lsquic as shared library.
- [OPTIMIZATION] Receive history: use a single contiguous memory
block for everything.
- Deprecate QUIC versions ID-27 and ID-30.

Connection ID Steering (#165)

Release 2.20.2

- [BUGFIX] Memory leak: free pushed promise when refcnt is zero.
- [BUGFIX] Memory leak in IETF full conn dtor: cleanup closed IDs sets.

Release 2.20.1

- [BUGFIX] Typo in new "validate peer addr by DCID" code. It is
a benign bug (works either way), but better to fix it.
- Simplify Stream Priority Iterator (SPI).
- Minor documentation updates.

Release 2.20.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 30 support.
- [FEATURE] Unreliable Datagram Extension support.
- [FEATURE] Adaptive congestion controller.
- [BUGFIX] Do not send MAX_STREAM_DATA frames on crypto streams.
- [BUGFIX] Fail with CRYPTO_BUFFER_EXCEEDED when too much CRYPTO
data comes in.
- [BUFFIX] Spin bit is now strictly per path; value is reset on
DCID change.
- [BUGFIX] Check that max value of max_streams_uni and
max_streams_bidi TPs is 2^60.
- [BUGFIX] Close IETF mini conn immediately if crypto session
cannot be initialized.
- Deprecate ID-28 (no browser uses it): it's no longer in the
default versions list.
- New programs duck_server and duck_client that implement the
experimental siduck-00 protocol. They quack!
- IETF crypto streams: don't limit ourselves from sending.
- Command-line programs: turn off QL loss bits if -G is used, as
Wireshark cannot decrypt QUIC packets when this extension is used.
- Turn all h3 framing unit tests back on.
- Fix malo initialization when compiled in no-pool mode.

Release 2.19.10 -- Fix Windows and MacOS builds

Release 2.19.9

- [FEATURE] Add lsquic_stream_pwritev(). This function allows one to
reduce the number of system calls required to read a file from disk
by using lsquic_stream_pwritev() together with preadv(2).
- [BUGFIX] When stream is reset, it is writeable -- let user collect
the error.
- [BUGFIX] Calculate correct conn flow control if reading ends early.
- [BUGFIX] Remove stream from read and write queues on internal
shutdown. This is a regression introduced in 2.19.7.
- [BUGFIX] Swapped arguments in IETF RESET_FRAME generation.
- Turn off mini conn history when compiling with Visual Studio; this
allows the project to compile on Windows again.
- http_client: Add -3 flag to stop reading from streams early; code
cleanup.
- Don't use -Werror.

Release 2.19.8

- [FEATURE] Update the timestamp extension to latest version.
- [FEATURE] Cope with appearance of ECN blackholes.
- [OPTIMIZATION] return packno offset and size when header is generated.
- [BUGFIX] ignore old ACK frames in mini conns.
- [BUGFIX] Mark initial server path as initialized.
- [BUGFIX] Do not merge ACK if ECN counts do not match.
- Turn incoming packet number history in mini conn back on.
- Record mini conn event history again when compiled in debug mode.
- IETF mini conn: log when ACK is queued.
- Clean up and refactor code in several places.

Release 2.19.7

- Handle ECT-CE event: issue a loss event.
- Log the fact that we ignore SETTINGS_MAX_HEADER_LIST_SIZE.
- Use Max Push ID in GOAWAY frame to cancel promises.
- Add support for HTTP/3 CANCEL_PUSH frame.
- lsquic_stream_is_pushed: streams without headers are never pushed.
- [BUGFIX] Regression in lsquic_stream_shutdown_internal: now it shuts down.
- Improve logic whether to generate CONNECTION_CLOSE.

Release 2.19.6

- Don't process incoming ECN marks if ECN is not enabled.
- Schedule ACK when incoming packet is marked with CE.

Release 2.19.5

- [BUGFIX] Generate frame record when moving an ACK from one buffered
packet to another.

Release 2.19.4

- [BUGFIX] Do not return an oversize MTU probe to connection twice.
- [FEATURE] Delayed Acks updated to latest draft. Still experimental.
- Minor code cleanup in IETF full connection.

Release 2.19.3

- [BUGFIX] Regression in 2.19.1 that breaks Q050

Release 2.19.2

- [BUGFIX] Do not reduce PLPMTU size by network overhead.
- [BUGFIX] Windows build.

Release 2.19.1 -- fix crash in IETF client (DPLPMTUD regression)

Release 2.19.0

- [FEATURE] DPLPMTUD support. IETF connections now search for the
maximum packet size, improving throughput.
- [DEBUG] Record event in stream history when on_close() is called
in dtor.

Release 2.18.2

- [BUGFIX] Send prediction: lone path challenges do not get squeezed out
- Fix crash in http_client: now -K and -B can be used simultaneously

Release 2.18.1

- [FEATURE] Implement the "QUIC bit grease" extension.
- [BUGFIX] Selecting CID used for logging on client.
- [BUGFIX] Header protection assertion.
- [BUGFIX] Server: enable SSL key logging when cert lookup callback
is not set.
- Remove some dead code.

Release 2.18.0

- [API] Rename "0-RTT" to "session resumption." In IETF QUIC, "0-RTT"
always refers to early data, meaning a request that the server can
reply to in the very first return flight. A more appropriate name
for what we support on the client site is "session resumption," which
is standard TLS terminology. Later, when we add support for 0-RTT
(early data), we can use the 0-RTT terminology again, this time in
proper context.
- [BUGFIX] Do not set certificate callback if ea_lookup_cert is NULL.
- [BUGFIX] Make connection tickable when it's marked as closed.
- [BUGFIX] Fail certificate lookup if SNI is not present in HTTP mode.
- Several documentation fixes and improvements.
- Minor code cleanup.

Release 2.17.2

- [BUGFIX] Infinite loop in stream: advance read offset when discarding data.
- [OPTIMIZATION] Header protection: only initialize cipher once.
- [OPTIMIZATION] Batch header protection application.

Release 2.17.1: fix regression in 2.17.0

Release 2.17.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 29 support.
- [BUGFIX] Check that scheduled packets are also sendable when
calculating a connection's "tickable" property.
- [BUGFIX] Don't count scheduled packets as in-flight when pacer is
checked on tick.
- gQUIC: delay calling on_new for pushed stream until headers are
available.
- Allow nested calls to lsquic_engine_connect().

Release 2.16.3

- [OPTIMIZATION] Stash up to two reordered packets in IETF mini conn
instead of dropping them.
- [BUGFIX] Crash: check decrypt context before using it. This regression
was introduced in 2.16.2.

Release 2.16.2

- [BUGFIX] ID-28: do not use TLS middlebox compatibility mode in
ClientHello. This change requires using a newer version of BoringSSL.
- [BUGFIX] Free connections in Advisory Tick Time Queue in engine dtor.
- [BUGFIX] IETF QUIC client: narrow migration check to a single path.
- [BUGFIX] NULL dereference: set function pointers for alarm for path
challenges 2 and 3.
- [BUGFIX] HTTP/3 headers may be followed immediately by trailers.
- [BUGFIX] Log messages when SCID changes.

Release 2.16.1

- [FEATURE] Use "no-progress timeout" after which connection is closed.
- [BUGFIX] Select new SCID when current SCID is retired.
- [BUGFIX] Don't warn about dropped Initial packet sequence gaps during
mini/full handoff.
- [BUGFIX] Send correct conn error when HTTP/3 frame is truncated.
- [BUGFIX] Mini conn: consider amplification when deciding to return
TICK_SEND.
- [BUGFIX] Don't double-count tag length in amplification logic.
- [BUGFIX] Don't squeeze out lone path challenges.
- [BUGFIX] Log messages dealing with scheduled packet queue squeezing.
- [BUGFIX] don't wipe current path if no path challenge responses
come back.
- [BUGFIX] When path is reset, don't lose path_id which is used for
logging.
- Downgrade flow control violations to info log level from warnings.
- Fix connection cap extra check, avoid checks in nested calls.
- Fix some unit tests when extra checks are enabled.
- Use ls-hpack 2.2.1.
- Turn off unconditional extra checks for IETF clients.
- Extra checks: don't verify sent size of hello packets. Client
changes DCID length and this check will fail.

Update version to 2.16.0

Fix Windows support

Release 2.15.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 28 support.
- [BUGFIX] Ignore Retry packets after other packets are decrypted
successfully.
- [BUGFIX] Transport parameter decoding: CID no longer has 4-byte
length minimum.
- http_client: fix and optimize lsxpack_header allocator.
- Drop support for Internet Draft 25.

Update version to 2.14.8

Release 2.14.7

- [BUGFIX] ALPN-to-version mapping: do not skip h3-Q050.
- [BUGFIX] Frame reader: skip headers if target stream is closed.

Release 2.14.6

- [BUGFIX] Fix amplification mitigation in 0-RTT case.
- [BUGFIX] IETF mini connection should not tickable if cannot send
a packet due to amplification.
- [BUGFIX] Fail if active_connection_id_limit TP is smaller than 2.
- [BUGFIX] Qlog server certificates for IETF QUIC connections.
- [BUGFIX] Uninitialized struct padding usage in tokgen (benign).
- [BUGFIX] Incorrect argument to shi_lookup() (benign).

Release 2.14.5

- [BUGFIX] In coalesced datagram, ignore packets whose CID does not match.
- [BUGFIX] Frame reader: skip headers if target stream is not found.
- [BUGFIX] Log message in QPACK decoder handler.

Release 2.14.4

- [BUGFIX] Heed es_rw_once for pushed HTTP/3 streams.
- [BUGFIX] IETF client: set correct flags on bidirectional streams.
- [BUGFIX] Generate Cancel Stream QPACK instructions for abandoned
streams.
- [BUGFIX] Do not call header callbacks after stream is closed.
- Use ls-qpack 2.1.1

Release 2.14.3

- [BUGFIX] gQUIC: pass correct stream to hsi_create_header_set() callback.
- [BUGFIX] Use ls-hpack 2.1.1
- Improve stream code readability.
- Use ls-qpack 2.0.5

Release 2.14.2

- [BUGFIX] Use ls-qpack 2.0.4
- [BUGFIX] Honor max packet size on the client and when path changes.
- http_server: fix prepare_decode() function.

Release 2.14.1

- [BUGFIX] Place connections on tickable queue when sending is reenabled.
- [BUGFIX] A connection is tickable if it has unsent packets.
- [BUGFIX] Heed peer's max_packet_size transport parameter.

Release 2.14.0

- [API] Use lsxpack_header structure to send HTTP headers.
- [OPTIMIZATION] nocopy's readable_bytes() function.
- http_server: fix typo in error message
- Use ls-hpack 2.1.0.
- Use ls-qpack 2.0.0.

Release 2.13.3

- [BUGFIX] ACK ping-pong: TIMESTAMP frame is not to be acked.

Release 2.13.2

- [BUGFIX] Use of new lsxpack_header API's hsi_prepare_decode().

Release 2.13.1 - fix a few minor issues flagged by Coverity

Release 2.13.0

- [API] Use lsxpack_header structure to process incoming headers.
- [BUGFIX] Fix assertion when zero-padding Initial packet.
- [BUGFIX] Use idle timeout before we learn of peer's value.
- Use ls-hpack 2.0.0 -- has lsxpack_header changes.
- Use ls-qpack 0.14.0 -- new, common with ls-hpack, XXH seed (not used yet).
- Code cleanup: prefix exported functions with "lsquic_".

Release 2.12.0

- [FEATURE] QUIC timestamps extension.
- [API] New: ea_alpn that is used when not in HTTP mode.
- [BUGFIX] SNI is mandatory only for HTTP/3 and gQUIC.
- [BUGFIX] Benign double-free -- issue #110.
- [BUGFIX] Printing of transport parameters.

API: add ea_alpn that is used when not in HTTP mode

Release 2.11.1: fix clang compilation

Release 2.11.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 27 support.
- [FEATURE] Add experimental delayed ACKs extension.
- Drop support for Internet Draft 24.
- Code cleanup.

Add experimental support for delayed ACKs extension

Switch to readthedocs.org for hosting documentation

Add API reference.

Code cleanup. Improve comments in lsquic.h

Release 2.10.6

- [BUGFIX] HTTP/3 framing: don't misinterpret rare occurence as error.
- [BUGFIX] Send gap warning due to missing poisoned packet.

Release 2.10.5

- [BUGFIX] BBR: call cci_sent() with correct arguments and at correct time.
- Refactor transport parameters module.
- Minor code cleanup.

Release 2.10.4

- [BUGFIX] Send HANDSHAKE_DONE only after Finished is received.
- [BUGFIX] Don't treat garbage UDP padding as library error; ignore
it instead.
- [BUGFIX] Fix compilation on FreeBSD (missing header).

Release 2.10.3

- [BUGFIX] Cancel path responses and challenges on old path when
switching to new path.
- Logging network path information.

Release 2.10.2

- [BUGFIX] Do not delay ACKs for Initial and Handshake packets.
- [BUGFIX] Send PATH_CHALLENGE if path changed before mini conn promotion.
- Logging improvements.
- http_client: discard data faster.

Release 2.10.1

- [BUGFIX] Coalesced packets could get longer than normal packet size.
- Add spin bit configuration option es_spin (-o spin=[01]).
- Disable spin bit in 1/16 of connections.
- Improve logging a bit.

Release 2.10.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 25 support.
- [API] Drop support for ID-23.
- [BUGFIX] Set key phase bit on outgoing packets correctly.
- Code cleanup.

Release 2.9.0

- [API] Drop support for Q039.
- Improve ACK-queuing logic. Send an ACK once in a while if
peer keeps on sending non-ack-eliciting packets.
- Improve Alt-Svc string: Q050 and later are not included in
the old-style "quic" string.
- Send stateless resets if connection could not be promoted.
- Schedule MAX_DATA if needed when DATA_BLOCKED is received.
- Use ls-qpack 0.11.2 -- needed for server push optimization.
- Code cleanup: handle some error cases, improve logging.

Release 2.8.9

- [BUGFIX] Use ls-qpack 0.11.1
- [OPTIMIZATION] Generate random bytes in batches.
- Change loss_bits transport parameter ID to 0x1057 following latest
draft.
- Randomize period with which PINGs are sent to elicit ACKs.
- Some refactoring and code cleanup.

Release 2.8.8

- [BUGFIX] Invalid read when parsing IETF transport parameters
(this was benign).
- [OPTIMIZATION] Frame bundling when using buffered packets in
IETF QUIC: a) flush QPACK decoder stream and b) include ACKs
in opportunistic fashion.
- Fix HTTP/3 framing unit test.
- Code cleanup.

Release 2.8.7

- [BUGFIX] Initial packet size check for IETF mini conn applies to
UDP payload, not QUIC packet.
- Support old and new school loss_bits transport parameter.
- Use Q run length of 64 as suggested in the loss bits Draft.
- Undo square wave count when packet is delayed.
- Code cleanup; minor fixes.

Release 2.8.5

- [BUGFIX] Fix unintended sign extension when removing header protection.

Release 2.8.4

- [HTTP3] Verify number of bytes in incoming DATA frames against
content-length.
- [HTTP3] Stop issuing streams credits if peer stops opening QPACK
decoder window. This addresses a potential attack whereby client
can cause the server to keep allocating memory. See Security
Considerations in the QPACK draft.
- [BUGFIX] Mini conn: don't shorten max packet size for Q050 and later.
- [BUGFIX] Init IETF connection flow controller using correct setting.
- Code cleanup and minor fixes.

Release 2.8.1

- [FEATURE] Use occasional packet number gaps to detect optimistic
ACK attacks.
- [BUGFIX] Q050 client: all packet numbers are in the App PNS.
- [OPTIMIZATION] Merge multi-range ACK frames, not just single-range
ACK frames.
- IETF QUIC: use RTT estimate in ack timeout calculation.
- IETF handshake: abort conn when unexpected errors occur.
- Use PING rather than MAX_DATA frames to elicit ACKs from peer.
- Server: enforce 1200 byte Initial minimum packet size.
- [CLEANUP] Remove code to disable gQUIC crypto.
- [CLEANUP] Remove n_timestamps from ACK info struct.
- Optimize driver: reuse previous ancillary message when possible.

Release 2.8.0

- [FEATURE] Add support for Q050.
- [OPTIMIZATION] Reduce mallocs in gQUIC handshake.
- [BUGFIX] Disable redo of failed STREAM frame insertion with debug
logging.

Release 2.7.3

- [DEBUG] Further dedup next advisory tick messages when reason is
the same.
- [BUGFIX] Update size of `a` array in TP struct. Fixes (benign)
GitHub bug #94.
- Use Cubic by default again instead of BBR, as it delivers more
consistent performance.

Release 2.7.2

- [BUGFIX] Send controller: update scheduled bytes when DCID length
changes (IETF client).
- [BUGFIX] Drop alarm check from sanity test. It no longer works now
that we use loss chains.
- [PORTABILITY] Fix build on Alpine Linux.
- [PORTABILITY] Fix build using XCode.
- Client initial DCID length: use RAND_bytes() instead of rand(3).
- Add unit tests for connection min heap.
- [DEBUG] Log CID in gQUIC handshake module
- [DEBUG] Turn on extra checks for IETF client send controller.
- [DEBUG] Dedup next advisory tick messages when reason is IDLE timer.
- [DEBUG] QPACK decoder handler: log header error code.

Release 2.7.1

- [BUGFIX] client: don't call ignore_init() in middle of batch send.
ignore_init() makes an assumption that the send controller has access
to all outgoing packets. This change wraps a few IETF full connection
methods to delay calling ignore_init() until the engine returns all
outgoing packets that were batched.
- [BUGFIX] set errno to EAGAIN if sendmmsg() can't send all of them.
This needs to be done because the value of errno may be lost on
some platforms.
- [BUGFIX] Typo that set all bits in sm_qflags lead to crashes.
- [BUGFIX] Do not cancel header block processing after failure, as
QPACK releases the reference in that case.
- [CLEANUP] IETF encrypt: replace assert(0) with a warning.
- Several small improvements to the test server.

Release 2.7.0

- [API, FEATURE] Close connection immediately when ea_packets_out()
fails with errno != EAGAIN. The API change is that errno is now
examined. Make sure to set it if using something other than
sendmsg() to send packets.
- [CLEANUP] Immediate close logic in IETF full conn.
- [CLEANUP] Fix bogus warning about uninitialized `pair' variable.

Release 2.6.7

- [FEATURE] Implement the QL extension (offered by default).
- [BUGFIX] Abort when encountering unexpected HTTP/3 frames.
- [BUGFIX] Acknowledge (QPACK) HTTP/3 trailers correctly.
- [DEBUG] Turn on debug message for next advisory tick.

Release 2.6.6

- [BUGFIX] Using HTTP/3 to HTTP/1.x converter.
- [BUGFIX] Truncate log messages instead of throwing them away.

Fix h3_framing unit test, bump version to 2.6.5

Release 2.6.4

- [BUGFIX] High priority buffered packet queue length.
- [BUGFIX] Rain time calculation: max_ack_delay is in milliseconds.

Release 2.6.3

- [BUGFIX] Close DATA frames with empty payload correctly.

Release 2.6.2

- [BUGFIX] SCID!=ODCID rule applies to Retry packets, not regular
packets.
- [BUGFIX] Zero-RTT: BoringSSL no longer flips read/write secrets.
- [BUGFIX] Truncate ACK frame rather instead of aborting IETF
connection.
- [BUGFIX] Client: don't send duplicate reset tokens.
- [BUGFIX] Remove invalid assertion in H3 framing code.
- Silence a warning in send ctl by restructuring switch() statement.

Release 2.6.1

- [BUGFIX] set retry token on all resubmitted packets.
- Event log: log sent packet flags. In particular, this allows one
to see whether token was sent.
- Don't migrate client if es_allow_migration is false.

Release 2.6.0

- [FEATURE] QUIC and HTTP/3 Internet Draft 24 support

Release 2.5.2

- [BUGFIX] argument order to gQUIC client constructor. Regression
introduced in 2.5.0.
- [BUGFIX] split buffered packet error recovery: destroy the correct
packet.

Release 2.5.1

- [BUGFIX] Fix double-free when emptying a packet number space.
- [BUGFIX] http_server: fix md5sum handler: handle EOF correctly.
- [BUGFIX] Use random values in bits 4 and 5 of the first byte of
verneg packets (regression introduced in 2.5.0).
- [OPTIMIZATION] Don't compile in expensive attq checks by default.
- [OPTIMIZATION] http_server: compile regexes only once.

Release 2.5.0

- [API] lsquic_engine_connect() can now be passed QUIC version to use.
- [OPTIMIZATION] Queue opportunistic ACKs if there is data to be sent.
- [BUGFIX] Don't evict streams from priority iterator if there is
only one queue.
- [OPTIMIZATION, BUGFIX] Several other optimizations and bug fixes.
- Use ls-qpack v0.10.7.

Release 2.4.10: fix regression in 2.4.9, use ls-qpack 0.10.6

Release 2.4.9

- [BUGFIX] IETF QUIC server: fix uninitialized variable use.
- [BUGFIX] make sure TLSv1.3 is not disabled in SSL object.
- [BUGFIX] Use issuer name and serial number to cache certs (SKID
values are not unique).
- [BUGFIX] Always set the idle alarm in IETF connection so that it
can time out.

Release 2.4.8

- [OPTIMIZATION, BUGFIX] Use ls-qpack v0.10.5.

Release 2.4.7

- Add echo client and server to the distibution.
- Add MD5 client and server to the distibution.
- Fix http_client: check command-line arguments better, prevent crash.
- Fix IETF conn: can_write_ack() should only care about APP PNS.
- Client: delay stream creation until handshake succeds.
- Reset HTTP stream whose write end is closed prematurely.
- Fix tickable(): mirror behavior of tick() wrt buffered packets.
- Log reason why engine is tickable.

Release 2.4.6

- Minor code cleanup and logging improvements.
- Server and client programs: include library version (e.g. 2.4.6)
into `server' and `user-agent' headers.

Release 2.4.5

- [OPTIMIZATION]: flush encoder stream only when necessary.
- [BUGFIX] Use ls-qpack v0.10.2 for new API -- and for a bug fix.
- [BUGFIX] Typo in IETF conn SETTINGS writer.
- Use latest BoringSSL.

Release 2.4.4

- [API] Add lsquic_alpn2ver() to aid parsing Alt-Svc header.
- [BUGFIX] NULL dereference when H3 frame header would be split.
- [BUGFIX] Do not close fixed-size H3 frame prematurely.
- [BUGFIX] Allow PING frames in IETF mini conn.
- [BUGFIX] Mini conns: don't send any packets after receiving
CONNECTION_CLOSE.
- [BUGFIX] Client migration: reserve slot for DCID from transport params.
- [BUGFIX] Allow max_early_data_size=0 -- early_data might not be there.
- [BUGFIX] Use an invalid stream number to reset BPT cache (zero is now a
valid stream number).
- [SPEC] Use FINAL_SIZE_ERROR when FIN mismatch is detected.
- [OPTIMIZATION] Closed connection only gets one chance to send packets.
- [OPTIMIZATION] Flush headers stream before packetizing stream data.
- [OPTIMIZATION] process QPACK encoder STREAM frames immediately.
- Update ls-qpack to v0.10.1.

Release 2.4.3

- Add GQUIC versions to the list of h3 ALPNs for Alt-Svc header.
For example, h3-Q043. Chrome will switch to using this format at
some point in the future.
- [BUGFIX] Send correct value in max_streams_uni transport param
- [SPEC] Abort IETF QUIC connection if max_early_data_size is not set
to 0xFFFFFFFF

Release 2.4.2

- [BUGFIX] H3 framing: fix zero-byte write when space is available
- [BUGFIX] Don't send STREAM frame when incoming unidirectgional stream
is closed
- [BUGFIX] Cancel all pending writes by stream reset by a GOAWAY
- [BUGFIX] Fix use-after-free in IETF full conn
- [OPTIMIZATION] Wait for session tickets for two seconds and then drop
SSL object and crypto streams.

Release 2.4.0

[FEATURE] QUIC and HTTP/3 Internet Draft 23 support

Release 2.3.1

- [BUGFIX] Fix memory leaks
- [BUGFIX] Fix unit tests

Release 2.3.0

- [FEATURE] BBR congestion control is on by default
- [BUGFIX] BBR app-limited logic
- [BUGFIX] Fix uninitialized warnings in IETF
- [BUGFIX] Update ls-qpack to v0.9.14
- [CLEANUP] Code cleanup

Release 2.2.0: server included, ID-22 supported (#76)

Release 1.21.2

- [OPTIMIZATION] HPACK: use history to improve compression performance

Release 1.21.1

- [BUGFIX] If FIN or RST not received, don't delay stream destruction.
- [OPTIMIZATION] Speed up HPACK encoder by using same hash value to
search static and dynamic tables.

Release 1.21.0

[FEATURE] Add qlog log module.

Release 1.20.0

[FEATURE] Add support for Q046.

Release 1.19.6

- [BUGFIX] Ensure that Largest Observed does not decrease in ACKs we
send. ACK frames placed in packets in buffered queues (optimization
introduced in 1.17.15) can be preceded by an ACK frame generated later.
In this case, the older ACK frame should not be sent out, as Chromium-
based servers flags decrease in the ACK frame's Largest Observed value
as an error.

Release 1.19.5

- [BUGFIX] Use correct public key from PUBS based on KEXS index.
- [BUGFIX] Check flags before dispatching writes, avoiding assert.
- [BUGFIX] Set :scheme to "https" (instead of "HTTP").

Release 1.19.4

- [BUGFIX] Check buffer bounds when looking up version in 0-RTT blob.
- [BUGFIX] http_client: don't fetch 0-rtt info if handshake failed.
- Log number of pacer calls at DEBUG, rather than NOTICE, level.

Release 1.19.3

- [BUGFIX] Q044: don't encode packet number in 6 bytes. Six-byte
packet number encoding does not exist in Q044. This fixes a
regression introduced in '[BUGFIX] Buffered packets can contain
ACK frames' -- we need to keep QUIC version in mind when selecting
the longest possible packet number encoding used for the buffered
packet that carries the ACK.
- [BUGFIX] Do not increase CWND when timeout occurs.
- http_client: support setting handshake timeout on command line.
Use -o handshake_to=timeout.
- http_client: use -k to connect UDP socket to pick up ICMP errors.
- http_client: allow pathless mode, when only handshake is performed
without issuing any requests. This can be done by simply not
specifying a -p flag on the command line.

Release 1.19.2

- [BUGFIX] Begin negotiation with version provided in 0-RTT info.
- [BUGFIX] Version checking in zero_rtt deserialize function.

Release 1.19.1 -- fix Windows build

Release 1.19.0

- [FEATURE, API Change] 0-RTT support. Add function to export 0-RTT
information; it can be supplied to a subsequent connect() call.
- [FEATURE] Add -0 flag to http_client to exercise 0-RTT support.
- [BUGFIX] Resuscitate the Windows build.
- [BUGFIX] Send HTTP settings (max header list size) if necessary.
- [BUGFIX] Buffered packets can contain ACK frames.
- [BUGFIX] Make packet writeable once all STREAM frames are elided.
- [BUGFIX] Fix potential null dereference when realloc fails.
- cmake: simplify build configuration.

Release 1.18.0

- [API Change] Can specify clock granularity in engine settings.
- [BUGFIX] Pacer uses fixed clock granularity. Since the change on
2018-04-09, it is not necessary to try to approximate the next tick
time in the pacer: it can use fix clock granularity specified by
the user.
- [BUGFIX] Do not tick constantly before handshake is done.
- [BUGFIX] Do not exit tick prematurely: reuse packet with ACK. Even
if we cannot allocate *more* packets, we could still be able to write
to one already allocated.
- [BUGFIX] Do not schedule pacer if there are no lost packets.

Release 1.17.15

- [BUGFIX] http_client: make sure only one read per on_read() callback
is performed in the header conversion bypass (-B) mode.
- http_client: with -E, assign random priority when stream is created.
- [OPTIMIZATION] On immediate write, place an ACK frame into the first
buffered packet if an ACK is queued. This reduces the number of
standalone ACK packets.
- [OPTIMIZATION] Allow placing more than one STREAM frame from the same
stream into an outgoing packet. This change minimizes the number of
buffered packets required to store several small HTTP messages by
virtue of allowing more than one STREAM frame from HEADERS stream in
the same packet.
- [OPTIMIZATION] Flush headers when writing to buffered packets. This
causes the headers to be written to the same buffered packet queue,
thereby improving packet utilization, especially for small HTTP
messages.

Release 1.17.14

- [FEATURE] http_client can now collect stats: time to connect, TTFB,
time to download, requests per seconds, and bandwidth. See -t flag.

- [BUGFIX] http_client: -B, -K, and -r can be used at the same time.

- [BUGFIX] http_client: do not display cert chain before each request.
Now this is only done once per connection, if the handshake is
successful and -a option is given.

- [BUGFIX] Do not wait to dispatch on_close() after reading. If a
stream is scheduled to be closed after on_read() callback returns,
close it immediately instead of waiting until the end of the tick.
If client creates new request from on_close() event, they will be
processed in the same tick instead of waiting for the next one.

- [BUGFIX] HEADERS stream is critical: always treat it with highest
priority.

Update header file and changelog: release 1.17.12

Release 1.17.11

Fix strict aliasing warning in when compiling with optimizations

Release 1.17.10

Fix the example program to be able to use parallel connections
again. (See the -n argument.)

Release 1.17.9

[BUGFIX] Engine: reduce minumum batch size from 256 to 4

Release 1.17.8

[BUGFIX] Fix compilation on FreeBSD and 32-bit Linux

Release 1.17.7

[BUGFIX] Do not unset PING alarm before ringing expired alarms. This
prevented PING from ever being sent.

Release 1.17.6

- Add failsafe: resume sending packets after some time

The change puts a 1-second limit on the amount of time the engine
will not send packets after some packets are delayed. This makes
the library robust in case the user does not unblock the engine
explicitly using lsquic_engine_send_unsent_packets() call.

- [BUGFIX] Handle corner cases in send controller when packets are
a) delayed or b) dropped during repackaging.

- [BUGFIX] Memory leak: destroy buffered packets during controller
cleanup.

Release 1.17.3

[BUGFIX] Do not send STOP_WAITING frames when using Q044

Release 1.17.2

- [BUGFIX] Memory leak in test_frame_rw unit test.
- [BUGFIX] Parsing packets with short IETF header: do not overwrite
flags. (Only a problem in unit tests -- benign otherwise.)

Release 1.17.0

- [API Change] Packet out Memory Interface (PMI) update:
- Split PMI pool return into pmi_release and pmi_return
- PMI callbacks take peer_ctx and is_ipv6 arguments
- [BUGFIX] Fix use-after-free when certificate is updated
- Silence gcc warning in optimized mode by performing useless
initialization
- cmake: use the standard variable CMAKE_BUILD_TYPE instead of
DEVEL_MODE

Release 1.16.0

- [API Change] Add lsquic_conn_n_avail_streams()
- [BUGFIX] only dispatch crypto stream read events if WANT_READ is on

Release 1.15.0

- [API Change] Add LSCONN_ST_PEER_GOING_AWAY to the list of conn statuses
- [BUGFIX] free uncompressed headers correctly when error occurs

Release 1.14.3

- [BUGFIX] Do not abort conn on STREAM frame for a reset stream
- [BUGFIX] Drop packets that would become empty due to repackaging.
Packets on the scheduled queue may be marked for repackaging.
Frames such as ACK frame that are never resent are removed from
repackaged packets. We must check that the newly repackaged packet
would not be empty. If it would be, it is destroyed instead and
the next packet on the scheduled queue is used. Note that this
change only affects the logic to return the next packet to be sent.
Lost packets that are being rescheduled are already processed in
this fashion.
- Byteswap CID before logging it - this makes it match Chrome CIDs.
(Except Q035, which is the last little-endian GQUIC version we
support.)

Release 1.14.0

- [API Change] Disable packet sending if full batch cannot be sent
If lsquic_packets_out_f() cannot send the whole batch, disable
packet sending until lsquic_engine_send_unsent_packets() is called.
- [BUGFIX] Handle case when STREAM frame does not fit.
- [BUGFIX] Always allow incoming STREAM frames to overlap. Peers
may send overlapping STREAM frames even if using versions older
than Q043.
- Custom header set fixes:
- set "FIN reached" flag when custom header with FIN flag is
claimed;
- do not return custom header set for a reset stream.

1.13.0: [FEATURE, API Change] HTTP header bypass

Add ability to create custom header set objects via callbacks.
This avoids reading and re-parsing headers from the stream.

See test/http_client.c for example implementation. (Use -B flag
to turn it on).

1.12.4: Fix memory leaks and gcc compilation warnings

1.12.3: [BUGFIX] Fix duplicate STREAM frame detection

1.12.2: Bugfix and log message improvements

1.12.0: [FEATURE, API Change] Certificate verification

1.11.1: [BUGFIX] Fix STOP_WAITING frame processing in the new Q044 code

1.11.0: [FEATURE] Add support for Q044

1.10.2: Don't go over limit when creating delayed streams

Latest changes

- 1.10.1
- [BUGFIX] process connections after each batch of packets is read
This avoids a problem of accumulating a very large list of packets
(possible when speeds are high and socket's receive buffer is large)
and processing it all at once.
- If glibc is older than 2.17, link with rt. This is necessary for
clock_getres(2).
- Add version macros to lsquic.h; remove unnecessary includes.

[BUGFIX] allow multiple parallel connections by default

Use the original method of tracking connections by CIDs by default.
If zero-sized CID support is turned on, connections are tracked by
the address. A new connection is not created if another connection
is using the same network address.

[FEATURE, API CHANGE] Support zero-sized CIDs in received packets

Latest changes

- [API Change] Add optional callback to call when handshake is done
- [API Change, BUGFIX] After send failure, wait until transport available

Latest changes:

- [API] Expose useful lsquic_ver2str[] in lsquic.h
- [BUGFIX] Do not produce packet sequence gaps due to STREAM frame elision

Drop support for Q041

Drop support for versions Q037, Q038, and Q042

[FEATURE] Add support for Q043

Version Q041 goes from experimental to deprecated

[FEATURE] Add support for Q042

Latest changes

- Remove comment: MSPC is obsolete (no code changes)
- Prog: use lsquic_str2ver() when processing -o version flag
- Remove unused CTIM and SRBF transport parameters
- Disable QUIC versions Q037 and Q038 by default
- Fix Windows compilation by including compat header file in lshpack.c
- Address warnings produced by newer versions of gcc
- Future-proof: turn off -Werror

Latest changes

- [BUGFIX] Add connection to Tickable Queue on stream write
- cmake: use MSVC variable instead of trying to detect
- engine: improve connection incref/decref logging
- stream: don't ignore errors that may occur on triggered flush
- connection: remove obsolete method
- engine: indicate connection as tickable if previous call went
over threshold

[API Change, OPTIMIZATION] Only process conns that need to be processed

The API is simplified: do not expose the user code to several
queues. A "connection queue" is now an internal concept.
The user processes connections using the single function
lsquic_engine_process_conns(). When this function is called,
only those connections are processed that need to be processed.
A connection needs to be processed when:

1. New incoming packets have been fed to the connection.
2. User wants to read from a stream that is readable.
3. User wants to write to a stream that is writeable.
4. There are buffered packets that can be sent out. (This
means that the user wrote to a stream outside of the
lsquic library callback.)
5. A control frame (such as BLOCKED) needs to be sent out.
6. A stream needs to be serviced or delayed stream needs to
be created.
7. An alarm rings.
8. Pacer timer expires.

To achieve this, the library places the connections into two
priority queues (min heaps):

1. Tickable Queue; and
2. Advisory Tick Time queue (ATTQ).

Each time lsquic_engine_process_conns() is called, the Tickable
Queue is emptied. After the connections have been ticked, they are
queried again: if a connection is not being closed, it is placed
either in the Tickable Queue if it is ready to be ticked again or
it is placed in the Advisory Tick Time Queue. It is assumed that
a connection always has at least one timer set (the idle alarm).

The connections in the Tickable Queue are arranged in the least
recently ticked order. This lets connections that have been quiet
longer to get their packets scheduled first.

This change means that the library no longer needs to be ticked
periodically. The user code can query the library when is the
next tick event and schedule it exactly. When connections are
processed, only the tickable connections are processed, not *all*
the connections. When there are no tick events, it means that no
timer event is necessary -- only the file descriptor READ event
is active.

The following are improvements and simplifications that have
been triggered:

- Queue of connections with incoming packets is gone.
- "Pending Read/Write Events" Queue is gone (along with its
history and progress checks). This queue has become the
Tickable Queue.
- The connection hash no longer needs to track the connection
insertion order.

Update copyright year; add CONTRIBUTORS.txt

Initial PlusWindows commit

compiles in debug/release. tests pass (in debug config at least)

Latest changes

- Fix unit test regression: enable them correctly in cmake.
- Simplify connection has interface

Latest changes

- [API Change] lsquic_engine_connect() returns pointer to the connection
object.
- [API Change] Add lsquic_conn_get_engine() to get engine object from
connection object.
- [API Change] Add lsquic_conn_status() to query connection status.
- [API Change] Add add lsquic_conn_set_ctx().
- [API Change] Add new timestamp format, e.g. 2017-03-21 13:43:46.671345
- [OPTIMIZATION] Process handshake STREAM frames as soon as packet
arrives.
- [OPTIMIZATION] Do not compile expensive send controller sanity check
by default.
- [OPTIMIZATION] Add fast path to gquic_be_gen_reg_pkt_header.
- [OPTIMIZATION] Only make squeeze function call if necessary.
- [OPTIMIZATION] Speed up Q039 ACK frame parsing.
- [OPTIMIZATION] Fit most used elements of packet_out into first 64 bytes.
- [OPTIMIZATION] Keep track of scheduled bytes instead of calculating.
- [OPTIMIZATION] Prefetch next unacked packet when processing ACK.
- [OPTIMIZATION] Leverage fact that ACK ranges and unacked list are.
ordered.
- [OPTIMIZATION] Reduce function pointer use for STREAM frame generation
- Fix: reset incoming streams that arrive after we send GOAWAY.
- Fix: delay client on_new_conn() call until connection is fully set up.
- Fixes to buffered packets logic: splitting, STREAM frame elision.
- Fix: do not dispatch on_write callback if no packets are available.
- Fix WINDOW_UPDATE send and resend logic.
- Fix STREAM frame extension code.
- Fix: Drop unflushed data when stream is reset.
- Switch to tracking CWND using bytes rather than packets.
- Fix TCP friendly adjustment in cubic.
- Fix: do not generate invalid STOP_WAITING frames during high packet
loss.
- Pacer fixes.

Add APIs.txt -- describe LSQUIC APIs on high level

Latest changes

- [API Change] Sendfile-like functionality is gone. The stream no
longer opens files and deals with file descriptors. (Among other
things, this makes the code more portable.) Three writing functions
are provided:

lsquic_stream_write
lsquic_stream_writev
lsquic_stream_writef (NEW)

lsquic_stream_writef() is given an abstract reader that has function
pointers for size() and read() functions which the user can implement.
This is the most flexible way. lsquic_stream_write() and
lsquic_stream_writev() are now both implemented as wrappers around
lsquic_stream_writef().

- [OPTIMIZATION] When writing to stream, be it within or without the
on_write() callback, place data directly into packet buffer,
bypassing auxiliary data structures. This reduces amount of memory
required, for the amount of data that can be written is limited
by the congestion window.

To support writes outside the on_write() callback, we keep N
outgoing packet buffers per connection which can be written to
by any stream. One half of these are reserved for the highest
priority stream(s), the other half for all other streams. This way,
low-priority streams cannot write instead of high-priority streams
and, on the other hand, low-priority streams get a chance to send
their packets out.

The algorithm is as follows:

- When user writes to stream outside of the callback:
- If this is the highest priority stream, place it onto the
reserved N/2 queue or fail.
(The actual size of this queue is dynamic -- MAX(N/2, CWND) --
rather than N/2, allowing high-priority streams to write as
much as can be sent.)
- If the stream is not the highest priority, try to place the
data onto the reserved N/2 queue or fail.
- When tick occurs *and* more packets can be scheduled:
- Transfer packets from the high N/2 queue to the scheduled
queue.
- If more scheduling is allowed:
- Call on_write callbacks for highest-priority streams,
placing resulting packets directly onto the scheduled queue.
- If more scheduling is allowed:
- Transfer packets from the low N/2 queue to the scheduled
queue.
- If more scheduling is allowed:
- Call on_write callbacks for non-highest-priority streams,
placing resulting packets directly onto the scheduled queue

The number N is currently 20, but it could be varied based on
resource usage.

- If stream is created due to incoming headers, make headers readable
from on_new.

- Outgoing packets are no longer marked non-writeable to prevent placing
more than one STREAM frame from the same stream into a single packet.
This property is maintained via code flow and an explicit check.
Packets for stream data are allocated using a special function.

- STREAM frame elision is cheaper, as we only perform it if a reset
stream has outgoing packets referencing it.

- lsquic_packet_out_t is smaller, as stream_rec elements are now
inside a union.

Latest changes

- Add support for Q041; drop support for Q040

LSQUIC Client: Initial release