Release 3.1.0

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 2.8.7

- [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 1.17.11

Fix strict aliasing warning in when compiling with optimizations

Update copyright year; add CONTRIBUTORS.txt

Latest changes

- [OPTIMIZATION] Merge series of ACKs if possible

Parsed single-range ACK frames (that is the majority of frames) are
saved in the connection and their processing is deferred until the
connection is ticked. If several ACKs come in a series between
adjacent ticks, we check whether the latest ACK is a strict superset
of the saved ACK. If it is, the older ACK is not processed.

If ACK frames can be merged, they are merged and only one of them is
either processed or saved.

- [OPTIMIZATION] Speed up ACK verification by simplifying send history.

Never generate a gap in the sent packet number sequence. This reduces
the send history to a single number instead of potentially a series of
packet ranges and thereby speeds up ACK verification.

By default, detecting a gap in the send history is not fatal: only a
single warning is generated per connection. The connection can continue
to operate even if the ACK verification code is not able to detect some
inconsistencies.

- [OPTIMIZATION] Rearrange the lsquic_send_ctl struct

The first part of struct lsquic_send_ctl now consists of members that
are used in lsquic_send_ctl_got_ack() (in the absense of packet loss,
which is the normal case). To speed up reads and writes, we no longer
try to save space by using 8- and 16-bit integers. Use regular integer
width for everything.

- [OPTIMIZATION] Cache size of sent packet.

- [OPTIMIZATION] Keep track of the largest ACKed in packet_out

Instead of parsing our own ACK frames when packet has been acked,
use the value saved in the packet_out structure when the ACK frame
was generated.

- [OPTIMIZATION] Take RTT sampling conditional out of ACK loop

- [OPTIMIZATION] ACK processing: only call clock_gettime() if needed

- [OPTIMIZATION] Several code-level optimizations to ACK processing.

- Fix: http_client: fix -I flag; switch assert() to abort()

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.

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.

LSQUIC Client: Initial release