CHANGELOG revision a686ef2a
12020-03-23
2    - 2.13.3
3    - [BUGFIX] ACK ping-pong: TIMESTAMP frame is not to be acked.
4
52020-03-13
6    - 2.13.2
7    - [BUGFIX] Use of new lsxpack_header API's hsi_prepare_decode().
8
92020-03-12
10    - 2.13.1
11    - [API] Use lsxpack_header structure to process incoming headers.
12    - [BUGFIX] Fix assertion when zero-padding Initial packet.
13    - [BUGFIX] Use idle timeout before we learn of peer's value.
14    - Use ls-hpack 2.0.1 -- has lsxpack_header changes.
15    - Use ls-qpack 0.14.0 -- new, common with ls-hpack, XXH seed (not
16      used yet).
17    - Code cleanup: prefix exported functions with "lsquic_".
18
192020-03-02
20    - 2.12.0
21    - [FEATURE] QUIC timestamps extension.
22    - [API] New: ea_alpn that is used when not in HTTP mode.
23    - [BUGFIX] SNI is mandatory only for HTTP/3 and gQUIC.
24    - [BUGFIX] Benign double-free -- issue #110.
25    - [BUGFIX] Printing of transport parameters.
26
272020-02-24
28    - 2.11.1
29    - [FEATURE] QUIC and HTTP/3 Internet Draft 27 support.
30    - [FEATURE] Add experimental delayed ACKs extension.
31    - Drop support for Internet Draft 24.
32    - Code cleanup.
33
342020-02-14
35    - 2.10.6
36    - [BUGFIX] HTTP/3 framing: don't misinterpret rare occurence as error.
37    - [BUGFIX] Send gap warning due to missing poisoned packet.
38    - Stream unit test for scenario in issue #106.
39
402020-02-13
41    - 2.10.5
42    - [BUGFIX] BBR: call cci_sent() with correct arguments and at correct
43      time.
44    - Refactor transport parameters module.
45    - Minor code cleanup.
46
472020-02-11
48    - 2.10.4
49    - [BUGFIX] Send HANDSHAKE_DONE only after Finished is received.
50    - [BUGFIX] Don't treat garbage UDP padding as library error; ignore
51      it instead.
52    - [BUGFIX] Fix compilation on FreeBSD (missing header).
53    - Code cleanup: remove unnecessary #includes.
54
552020-01-31
56    - 2.10.3
57    - [BUGFIX] Cancel path responses and challenges on old path when
58      switching to new path
59    - Logging network path information.
60
612020-01-30
62    - 2.10.2
63    - [BUGFIX] Do not delay ACKs for Initial and Handshake packets.
64    - [BUGFIX] Send PATH_CHALLENGE if path changed before mini conn
65      promotion.
66    - Logging improvements.
67    - http_client: discard data faster.
68
692020-01-29
70    - 2.10.1
71    - [BUGFIX] Coalesced packets could get longer than normal packet
72      size.
73    - Add spin bit configuration option es_spin (-o spin=[01]).
74    - Disable spin bit in 1/16 of connections.
75    - Improve logging a bit.
76
772020-01-28
78    - 2.10.0
79    - [FEATURE] QUIC and HTTP/3 Internet Draft 25 support.
80    - [API] Drop support for ID-23.
81    - [BUGFIX] Set key phase bit on outgoing packets correctly.
82    - Code cleanup.
83
842020-01-20
85    - 2.9.0
86    - [API] Drop support for Q039.
87    - Improve ACK-queuing logic.  Send an ACK once in a while if
88      peer keeps on sending non-ack-eliciting packets.
89    - Improve Alt-Svc string: Q050 and later are not included in
90      the old-style "quic" string.
91    - Send stateless resets if connection could not be promoted.
92    - Schedule MAX_DATA if needed when DATA_BLOCKED is received.
93    - Use ls-qpack 0.11.2 -- needed for server push optimization.
94    - Code cleanup: handle some error cases, improve logging.
95
962020-01-16
97    - 2.8.9
98    - [BUGFIX] Use ls-qpack 0.11.1
99    - [OPTIMIZATION] Generate random bytes in batches.
100    - Change loss_bits transport parameter ID to 0x1057 following
101      latest draft.
102    - Randomize period with which PINGs are sent to elicit ACKs.
103    - Some refactoring and code cleanup.
104
1052020-01-14
106    - 2.8.8
107    - [BUGFIX] Invalid read when parsing IETF transport parameters
108      (this was benign).
109    - [OPTIMIZATION] Frame bundling when using buffered packets in
110      IETF QUIC: a) flush QPACK decoder stream and b) include ACKs
111      in opportunistic fashion.
112    - Fix HTTP/3 framing unit test.
113    - Code cleanup.
114
1152020-01-09
116    - 2.8.7
117    - [BUGFIX] Initial packet size check for IETF mini conn applies to
118      UDP payload, not QUIC packet.
119    - Support old and new school loss_bits transport parameter.
120    - Use Q run length of 64 as suggested in the loss bits Draft.
121    - Undo square wave count when packet is delayed.
122    - Code cleanup; minor fixes.
123
1242020-01-06
125    - 2.8.5
126    - [HTTP3] Verify number of bytes in incoming DATA frames against
127      content-length.
128    - [HTTP3] Stop issuing streams credits if peer stops opening QPACK
129      decoder window.  This addresses a potential attack whereby client
130      can cause the server to keep allocating memory.  See Security
131      Considerations in the QPACK draft.
132    - [BUGFIX] Mini conn: don't shorten max packet size for Q050 and later.
133    - [BUGFIX] Init IETF connection flow controller using correct setting.
134    - [BUGFIX] Fix unintended sign extension when removing header protection.
135    - Code cleanup and minor fixes.
136
1372019-12-30
138    - 2.8.1
139    - [FEATURE] Use occasional packet number gaps to detect optimistic
140      ACK attacks.
141    - [BUGFIX] Q050 client: all packet numbers are in the App PNS.
142    - [OPTIMIZATION] Merge multi-range ACK frames, not just single-range
143      ACK frames.
144    - IETF QUIC: use RTT estimate in ack timeout calculation.
145    - IETF handshake: abort conn when unexpected errors occur.
146    - Use PING rather than MAX_DATA frames to elicit ACKs from peer.
147    - Server: enforce 1200 byte Initial minimum packet size.
148    - [CLEANUP] Remove code to disable gQUIC crypto.
149    - [CLEANUP] Remove n_timestamps from ACK info struct.
150    - Optimize driver: reuse previous ancillary message when possible.
151
1522019-12-23
153    - 2.8.0
154    - [FEATURE] Add support for Q050.
155    - [OPTIMIZATION] Reduce mallocs in gQUIC handshake.
156    - [BUGFIX] Disable redo of failed STREAM frame insertion with debug
157      logging.
158
1592019-12-18
160    - 2.7.3
161    - [DEBUG] Further dedup next advisory tick messages when reason is
162      the same.
163    - [BUGFIX] Update size of `a` array in TP struct.  Fixes (benign)
164      GitHub bug #94.
165    - Use Cubic by default again instead of BBR, as it delivers more
166      consistent performance.
167
1682019-12-11
169    - 2.7.2
170    - [BUGFIX] Send controller: update scheduled bytes when DCID length
171      changes (IETF client).
172    - [BUGFIX] Drop alarm check from sanity test.  It no longer works now
173      that we use loss chains.
174    - [PORTABILITY] Fix build on Alpine Linux.
175    - [PORTABILITY] Fix build using XCode.
176    - Client initial DCID length: use RAND_bytes() instead of rand(3).
177    - Add unit tests for connection min heap.
178    - [DEBUG] Log CID in gQUIC handshake module
179    - [DEBUG] Turn on extra checks for IETF client send controller.
180    - [DEBUG] Dedup next advisory tick messages when reason is IDLE timer.
181    - [DEBUG] QPACK decoder handler: log header error code.
182
1832019-12-05
184    - 2.7.1
185    - [BUGFIX] client: don't call ignore_init() in middle of batch send.
186      ignore_init() makes an assumption that the send controller has access
187      to all outgoing packets.  This change wraps a few IETF full connection
188      methods to delay calling ignore_init() until the engine returns all
189      outgoing packets that were batched.
190    - [BUGFIX] set errno to EAGAIN if sendmmsg() can't send all of them.
191      This needs to be done because the value of errno may be lost on
192      some platforms.
193    - [BUGFIX] Typo that set all bits in sm_qflags lead to crashes.
194    - [BUGFIX] Do not cancel header block processing after failure, as
195      QPACK releases the reference in that case.
196    - [CLEANUP] IETF encrypt: replace assert(0) with a warning.
197    - Several small improvements to the test server.
198
1992019-11-27
200    - 2.7.0
201    - [API, FEATURE] Close connection immediately when ea_packets_out()
202      fails with errno != EAGAIN.  The API change is that errno is now
203      examined.  Make sure to set it if using something other than
204      sendmsg() to send packets.
205    - [CLEANUP] Immediate close logic in IETF full conn.
206    - [CLEANUP] Fix bogus warning about uninitialized `pair' variable.
207
2082019-11-22
209    - 2.6.7
210    - [FEATURE] Implement the QL extension (offered by default).
211    - [BUGFIX] Abort when encountering unexpected HTTP/3 frames.
212    - [BUGFIX] Acknowledge (QPACK) HTTP/3 trailers correctly.
213    - [DEBUG] Turn on debug message for next advisory tick.
214
2152019-11-20
216    - 2.6.6
217    - [BUGFIX] Using HTTP/3 to HTTP/1.x converter.
218    - [BUGFIX] Truncate log messages instead of throwing them away.
219
2202019-11-15
221    - 2.6.5
222    - [BUGFIX] High priority buffered packet queue length.
223    - [BUGFIX] Rain time calculation: max_ack_delay is in milliseconds.
224
2252019-11-12
226    - 2.6.3
227    - [BUGFIX] Close DATA frames with empty payload correctly.
228
2292019-11-11
230    - 2.6.2
231    - [BUGFIX] SCID!=ODCID rule applies to Retry packets, not regular
232      packets.
233    - [BUGFIX] Zero-RTT: BoringSSL no longer flips read/write secrets.
234    - [BUGFIX] Truncate ACK frame rather instead of aborting IETF
235      connection.
236    - [BUGFIX] Client: don't send duplicate reset tokens.
237    - [BUGFIX] Remove invalid assertion in H3 framing code.
238    - Silence a warning in send ctl by restructuring switch() statement.
239
2402019-11-08
241    - 2.6.1
242    - [BUGFIX] set retry token on all resubmitted packets.
243    - Event log: log sent packet flags.  In particular, this allows one
244      to see whether token was sent.
245    - Don't migrate client if es_allow_migration is false.
246
2472019-11-07
248    - 2.6.0
249    - [FEATURE] QUIC and HTTP/3 Internet Draft 24 support
250
2512019-11-07
252    - 2.5.2
253    - [BUGFIX] argument order to gQUIC client constructor.  Regression
254      introduced in 2.5.0.
255    - [BUGFIX] split buffered packet error recovery: destroy the correct
256      packet.
257
2582019-11-04
259    - 2.5.1
260    - [BUGFIX] Fix double-free when emptying a packet number space.
261    - [BUGFIX] http_server: fix md5sum handler: handle EOF correctly.
262    - [BUGFIX] Use random values in bits 4 and 5 of the first byte of
263      verneg packets (regression introduced in 2.5.0).
264    - [OPTIMIZATION] Don't compile in expensive attq checks by default.
265    - [OPTIMIZATION] http_server: compile regexes only once.
266
2672019-10-31
268    - 2.5.0
269    - [API] lsquic_engine_connect() can now be passed QUIC version to use.
270    - [OPTIMIZATION] Queue opportunistic ACKs if there is data to be sent.
271    - [BUGFIX] Don't evict streams from priority iterator if there is
272      only one queue.
273    - [OPTIMIZATION, BUGFIX] Several other optimizations and bug fixes.
274    - Use ls-qpack v0.10.7.
275
2762019-10-24
277    - 2.4.10
278    - [BUGFIX] IETF QUIC server: fix uninitialized variable use.
279    - [BUGFIX] make sure TLSv1.3 is not disabled in SSL object.
280    - [BUGFIX] Use issuer name and serial number to cache certs (SKID
281      values are not unique).
282    - [BUGFIX] Always set the idle alarm in IETF connection so that it
283      can time out.
284    - Use ls-qpack v0.10.6, as it silences some warnings.
285
2862019-10-21
287    - 2.4.8
288    - [OPTIMIZATION, BUGFIX] Use ls-qpack v0.10.5.
289
2902019-10-15
291    - 2.4.7
292    - Add echo client and server to the distibution.
293    - Add MD5 client and server to the distibution.
294    - Fix http_client: check command-line arguments better, prevent crash.
295    - Fix IETF conn: can_write_ack() should only care about APP PNS.
296    - Client: delay stream creation until handshake succeds.
297    - Reset HTTP stream whose write end is closed prematurely.
298    - Fix tickable(): mirror behavior of tick() wrt buffered packets.
299    - Log reason why engine is tickable.
300
3012019-10-11
302    - 2.4.6
303    - Minor code cleanup and logging improvements.
304    - Server and client programs: include library version (e.g. 2.4.6)
305      into `server' and `user-agent' headers.
306
3072019-10-08
308    - 2.4.5
309    - [OPTIMIZATION]: flush encoder stream only when necessary.
310    - [BUGFIX] Use ls-qpack v0.10.2 for new API -- and for a bug fix.
311    - [BUGFIX] Typo in IETF conn SETTINGS writer.
312    - Use latest BoringSSL.
313
3142019-10-08
315    - 2.4.4
316    - [API] Add lsquic_alpn2ver() to aid parsing Alt-Svc header.
317    - [BUGFIX] NULL dereference when H3 frame header would be split.
318    - [BUGFIX] Do not close fixed-size H3 frame prematurely.
319    - [BUGFIX] Allow PING frames in IETF mini conn.
320    - [BUGFIX] Mini conns: don't send any packets after receiving
321      CONNECTION_CLOSE.
322    - [BUGFIX] Client migration: reserve slot for DCID from transport params.
323    - [BUGFIX] Allow max_early_data_size=0 -- early_data might not be there.
324    - [BUGFIX] Use an invalid stream number to reset BPT cache (zero is now a
325      valid stream number).
326    - [SPEC] Use FINAL_SIZE_ERROR when FIN mismatch is detected.
327    - [OPTIMIZATION] Closed connection only gets one chance to send packets.
328    - [OPTIMIZATION] Flush headers stream before packetizing stream data.
329    - [OPTIMIZATION] process QPACK encoder STREAM frames immediately.
330    - Update ls-qpack to v0.10.1.
331
3322019-09-30
333    - 2.4.3
334    - Add GQUIC versions to the list of h3 ALPNs for Alt-Svc header.
335      For example, h3-Q043.  Chrome will switch to using this format at
336      some point in the future.
337    - [BUGFIX] Send correct value in max_streams_uni transport param
338    - [SPEC] Abort IETF QUIC connection if max_early_data_size is not set
339      to 0xFFFFFFFF
340
3412019-09-23
342    - 2.4.2
343    - [BUGFIX] H3 framing: fix zero-byte write when space is available
344    - [BUGFIX] Don't send STREAM frame when incoming unidirectgional stream
345      is closed
346    - [BUGFIX] Cancel all pending writes by stream reset by a GOAWAY
347    - [BUGFIX] Fix use-after-free in IETF full conn
348    - [OPTIMIZATION] Wait for session tickets for two seconds and then drop
349      SSL object and crypto streams.
350
3512019-09-18
352    - 2.4.0
353    - [FEATURE] QUIC and HTTP/3 Internet Draft 23 support
354
3552019-09-13
356    - 2.3.1
357    - [BUGFIX] Fix memory leaks
358    - [BUGFIX] Fix unit tests
359
3602019-09-12
361    - 2.3.0
362    - [FEATURE] BBR congestion control is on by default
363    - [BUGFIX] BBR app-limited logic
364    - [BUGFIX] Fix uninitialized warnings in IETF
365    - [BUGFIX] Update ls-qpack to v0.9.14
366    - [CLEANUP] Code cleanup
367
3682019-09-11
369    - 2.2.0
370    - [FEATURE] Server code is included in the library
371    - [FEATURE] IETF QUIC and HTTP/3 Support (ID-22)
372
3732019-05-13
374    - 1.21.2
375    - [OPTIMIZATION] HPACK: use history to improve compression performance
376
3772019-05-06
378    - 1.21.1
379    - [BUGFIX] If FIN or RST not received, don't delay stream destruction.
380    - [OPTIMIZATION] Speed up HPACK encoder by using same hash value to
381      search static and dynamic tables.
382
3832019-04-12
384    - 1.21.0
385    - [FEATURE] Add qlog log module.
386
3872019-04-01
388    - 1.20.0
389    - [FEATURE] Add support for Q046.
390
3912019-03-19
392    - 1.19.6
393    - [BUGFIX] Ensure that Largest Observed does not decrease in ACKs we
394      send.  ACK frames placed in packets in buffered queues (optimization
395      introduced in 1.17.15) can be preceded by an ACK frame generated later.
396      In this case, the older ACK frame should not be sent out, as Chromium-
397      based servers flags decrease in the ACK frame's Largest Observed value
398      as an error.
399
4002019-03-05
401    - 1.19.5
402    - [BUGFIX] Use correct public key from PUBS based on KEXS index.
403    - [BUGFIX] Check flags before dispatching writes, avoiding assert.
404    - [BUGFIX] Set :scheme to "https" (instead of "HTTP").
405
4062019-02-25
407    - 1.19.4
408    - [BUGFIX] Check buffer bounds when looking up version in 0-RTT blob.
409    - [BUGFIX] http_client: don't fetch 0-rtt info if handshake failed.
410    - Log number of pacer calls at DEBUG, rather than NOTICE, level.
411
4122019-02-18
413    - 1.19.3
414    - [BUGFIX] Q044: don't encode packet number in 6 bytes.  Six-byte
415      packet number encoding does not exist in Q044.  This fixes a
416      regression introduced in '[BUGFIX] Buffered packets can contain
417      ACK frames' -- we need to keep QUIC version in mind when selecting
418      the longest possible packet number encoding used for the buffered
419      packet that carries the ACK.
420    - [BUGFIX] Do not increase CWND when timeout occurs.
421    - http_client: support setting handshake timeout on command line.
422      Use -o handshake_to=timeout.
423    - http_client: use -k to connect UDP socket to pick up ICMP errors.
424    - http_client: allow pathless mode, when only handshake is performed
425      without issuing any requests.  This can be done by simply not
426      specifying a -p flag on the command line.
427
4282019-02-11
429    - 1.19.2
430    - [BUGFIX] Begin negotiation with version provided in 0-RTT info.
431    - [BUGFIX] Version checking in zero_rtt deserialize function.
432
4332019-02-04
434    - 1.19.1
435    - [BUGFIX] Fix Windows build.
436
4372019-02-04
438    - 1.19.0
439    - [FEATURE, API Change] 0-RTT support.  Add function to export 0-RTT
440      information; it can be supplied to a subsequent connect() call.
441    - [FEATURE] Add -0 flag to http_client to exercise 0-RTT support.
442    - [BUGFIX] Resuscitate the Windows build.
443    - [BUGFIX] Send HTTP settings (max header list size) if necessary.
444    - [BUGFIX] Buffered packets can contain ACK frames.
445    - [BUGFIX] Make packet writeable once all STREAM frames are elided.
446    - [BUGFIX] Fix potential null dereference when realloc fails.
447    - cmake: simplify build configuration.
448
4492019-01-28
450    - 1.18.0
451    - [API Change] Can specify clock granularity in engine settings.
452    - [BUGFIX] Pacer uses fixed clock granularity.  Since the change on
453      2018-04-09, it is not necessary to try to approximate the next tick
454      time in the pacer: it can use fix clock granularity specified by
455      the user.
456    - [BUGFIX] Do not tick constantly before handshake is done.
457    - [BUGFIX] Do not exit tick prematurely: reuse packet with ACK.  Even
458      if we cannot allocate *more* packets, we could still be able to write
459      to one already allocated.
460    - [BUGFIX] Do not schedule pacer if there are no lost packets.
461
4622019-01-17
463    - 1.17.15
464    - [BUGFIX] http_client: make sure only one read per on_read() callback
465      is performed in the header conversion bypass (-B) mode.
466    - http_client: with -E, assign random priority when stream is created.
467    - [OPTIMIZATION] On immediate write, place an ACK frame into the first
468      buffered packet if an ACK is queued.  This reduces the number of
469      standalone ACK packets.
470    - [OPTIMIZATION] Allow placing more than one STREAM frame from the same
471      stream into an outgoing packet.  This change minimizes the number of
472      buffered packets required to store several small HTTP messages by
473      virtue of allowing more than one STREAM frame from HEADERS stream in
474      the same packet.
475    - [OPTIMIZATION] Flush headers when writing to buffered packets.  This
476      causes the headers to be written to the same buffered packet queue,
477      thereby improving packet utilization, especially for small HTTP
478      messages.
479
4802019-01-16
481    - 1.17.14
482    - [FEATURE] http_client can now collect stats: time to connect, TTFB,
483      time to download, requests per seconds, and bandwidth.  See -t flag.
484    - [BUGFIX] http_client: -B, -K, and -r can be used at the same time.
485    - [BUGFIX] http_client: do not display cert chain before each request.
486      Now this is only done once per connection, if the handshake is
487      successful and -a option is given.
488    - [BUGFIX] Do not wait to dispatch on_close() after reading.  If a
489      stream is scheduled to be closed after on_read() callback returns,
490      close it immediately instead of waiting until the end of the tick.
491      If client creates new request from on_close() event, they will be
492      processed in the same tick instead of waiting for the next one.
493    - [BUGFIX] HEADERS stream is critical: always treat it with highest
494      priority.
495
4962019-01-10
497    - 1.17.12
498    - [FEATURE] http_client can now issue parallel requests in the context
499      of a single connection.  See -w option.
500
5012019-01-03
502    - 1.17.11
503    - Fix strict aliasing warning in optimized compilation.
504
5052018-12-27
506    - 1.17.10
507    - Fix the example program to be able to use parallel connections
508      again.  (See the -n argument.)
509
5102018-12-18
511    - 1.17.9
512    - [BUGFIX] Engine: reduce minimum batch size from 256 to 4
513
5142018-12-10
515    - 1.17.8
516    - [BUGFIX] Fix compilation on FreeBSD and 32-bit Linux
517
5182018-12-03
519    - 1.17.7
520    - [BUGFIX] Do not unset PING alarm before ringing expired alarms.
521      This prevented PING from ever being sent.
522
5232018-11-29
524    - 1.17.6
525    - Add failsafe: resume sending packets after some time
526
527      The change puts a 1-second limit on the amount of time the engine
528      will not send packets after some packets are delayed.  This makes
529      the library robust in case the user does not unblock the engine
530      explicitly using lsquic_engine_send_unsent_packets() call.
531
532    - [BUGFIX] Handle corner cases in send controller when packets are
533      a) delayed or b) dropped during repackaging.
534    - [BUGFIX] Memory leak: destroy buffered packets during controller
535      cleanup.
536
5372018-11-16
538    - 1.17.3
539    - [BUGFIX] Do not send STOP_WAITING frames when using Q044
540
5412018-10-19
542    - 1.17.2
543    - [BUGFIX] Memory leak in test_frame_rw unit test.
544    - [BUGFIX] Parsing packets with short IETF header: do not overwrite
545      flags.  (Only a problem in unit tests -- benign otherwise.)
546
5472018-10-16
548    - 1.17.0
549    - [API Change] Packet out Memory Interface (PMI) update:
550      - Split PMI pool return into pmi_release and pmi_return
551      - PMI callbacks take peer_ctx and is_ipv6 arguments
552    - [BUGFIX] Fix use-after-free when certificate is updated
553    - Silence gcc warning in optimized mode by performing useless
554      initialization
555    - cmake: use the standard variable CMAKE_BUILD_TYPE instead of
556      DEVEL_MODE
557
5582018-10-03
559    - 1.16.0
560    - [API Change] Add lsquic_conn_n_avail_streams()
561    - [BUGFIX] only dispatch crypto stream read events if WANT_READ is on
562
5632018-09-27
564    - 1.15.0
565    - [API Change] Add LSCONN_ST_PEER_GOING_AWAY to the list of conn statuses
566    - [BUGFIX] free uncompressed headers correctly when error occurs
567
5682018-09-12
569    - 1.14.3
570    - [BUGFIX] Do not abort conn on STREAM frame for a reset stream
571    - [BUGFIX] Drop packets that would become empty due to repackaging.
572      Packets on the scheduled queue may be marked for repackaging.
573      Frames such as ACK frame that are never resent are removed from
574      repackaged packets.  We must check that the newly repackaged packet
575      would not be empty.  If it would be, it is destroyed instead and
576      the next packet on the scheduled queue is used.  Note that this
577      change only affects the logic to return the next packet to be sent.
578      Lost packets that are being rescheduled are already processed in
579      this fashion.
580    - Byteswap CID before logging it - this makes it match Chrome CIDs.
581      (Except Q035, which is the last little-endian GQUIC version we
582      support.)
583
5842018-09-06
585    - 1.14.0
586    - [API Change] Disable packet sending if full batch cannot be sent
587      If lsquic_packets_out_f() cannot send the whole batch, disable
588      packet sending until lsquic_engine_send_unsent_packets() is called.
589    - [BUGFIX] Handle case when STREAM frame does not fit.
590    - [BUGFIX] Always allow incoming STREAM frames to overlap.  Peers
591      may send overlapping STREAM frames even if using versions older
592      than Q043.
593    - Custom header set fixes:
594      - set "FIN reached" flag when custom header with FIN flag is
595        claimed;
596      - do not return custom header set for a reset stream.
597
5982018-08-27
599
600    - 1.13.0
601    - [FEATURE, API Change] Add ability to create custom header set
602      objects via callbacks.  This avoids reading and re-parsing
603      headers from the stream.
604
6052018-08-27
606
607    - 1.12.4
608    - Fix memory leak when engine is destroyed
609    - Fix memory leak in http_client
610    - Fix gcc warning in unit tests
611
6122018-08-22
613
614    - 1.12.3
615    - [BUGFIX] Fix duplicate STREAM frame detection
616
6172018-08-20
618
619    - 1.12.2
620    - [BUGFIX] Update count of scheduled bytes when adjusting size of
621      an already-scheduled packet.
622    - Emit info instead of warning messages when stream is used in
623      unexpected ways.
624
6252018-08-17
626
627    - 1.12.0
628    - [FEATURE, API Change] Add support for certificate verification
629
6302018-08-16
631
632    - 1.11.1
633    - [BUGFIX] Fix STOP_WAITING frame processing in the new Q044 code
634
6352018-08-15
636
637    - 1.11.0
638    - [FEATURE] Add support for Q044.
639
6402018-08-09
641
642    - 1.10.2
643    - [BUGFIX] Don't go over limit when creating delayed streams
644
6452018-07-10
646
647    - 1.10.1
648    - [BUGFIX]  process connections after each batch of packets is read
649      This avoids a problem of accumulating a very large list of packets
650      (possible when speeds are high and socket's receive buffer is large)
651      and processing it all at once.
652    - If glibc is older than 2.17, link with rt.  This is necessary for
653      clock_getres(2).
654    - Add version macros to lsquic.h; remove unnecessary includes.
655
6562018-06-13
657
658    - [BUGFIX] allow multiple parallel connections by default
659
660      Use the original method of tracking connections by CIDs by default.
661      If zero-sized CID support is turned on, connections are tracked by
662      the address.  A new connection is not created if another connection
663      is using the same network address
664
6652018-05-30
666
667    - [FEATURE, API CHANGE] Support zero-sized CIDs in received packets
668
6692018-05-24
670
671    - Close connection properly when packet encryption fails
672
6732018-05-23
674
675    - [BUGFIX] Do not produce packet sequence gaps due to delayed packets
676
6772018-05-21
678
679    - [API Change] Add optional callback to call when handshake is done
680    - [API Change, BUGFIX] After send failure, wait until transport available
681
6822018-05-18
683
684    - [API] Expose useful lsquic_ver2str[] in lsquic.h
685    - [BUGFIX] Do not produce packet sequence gaps due to STREAM frame elision
686    - Improve checks of number of incoming streams limit and associated
687      error reporting.
688    - [BUGFIX] Command-line option `-6` now works correctly.
689
6902018-05-16
691
692    - [FEATURE] DNS resolution
693    - [BUGFIX] Frame insertion mis-ID as overlap instead of dup
694    - http_client: fix priority range generated by -E flag
695
6962018-05-09
697
698    - [FEATURE] Add support for Q043.
699    - Support for versions Q037, Q038, Q041, and Q042 has been removed.
700    - Fix typo in debug message.
701    - Fix code indentation.
702    - Add /* fallthru */ comment to stop newer gcc from complaining.
703    - Logger: fix compilation of optimized Windows build.
704
7052018-05-04
706
707    - [FEATURE] Add support for Q042.
708    - Remove comment: MSPC is obsolete (no code changes)
709    - Prog: use lsquic_str2ver() when processing -o version flag
710    - Remove unused CTIM and SRBF transport parameters
711    - Disable QUIC versions Q037 and Q038 by default
712    - Fix Windows compilation by including compat header file in
713      lshpack.c
714    - Address warnings produced by newer versions of gcc
715    - Future-proof: turn off -Werror
716
7172018-05-02
718
719    - [BUGFIX] Make lsquic_conn_quic_version() available
720    - Switch to using ls-hpack 1.1
721    - [BUGFIX] Do not ignore stream resets after receiving FIN
722
7232018-04-27
724
725    - HPACK: do not allow header block to end with table size update.
726
7272018-04-25
728
729    - [BUGFIX] Do not create gap in sent packnos when squeezing delayed
730      packets.
731    - [BUGFIX] sendctl checks for all unacked bytes, not just retx bytes.
732    - [BUGFIX] connections with blocked scheduled packets are not tickable
733      for sending.
734    - [BUGFIX] Conn is tickable if it wants to send a connection-level
735      frame.
736
7372018-04-23
738
739    - Fix busy loop: tickable must make progress.  When connection is
740      self-reporting as tickable, it must make progress when ticked.  There
741      are two issues:
742        1. If there are buffered packets, the connection is only tickable if
743           they can be sent out.
744        2. A connection is tickable if there are streams on the servicing
745           queue.  When the tick occurs, we must service the stream
746           independent of whether any packets are sent.
747    - Fix assertion in pacer which can be incorrect under some
748      conditions.
749    - cmake: do not turn on address sanitizer if in Travis.
750
7512018-04-20
752
753    - [BUGFIX] Fix bug in lsquic_engine_connect() exposed by yesterday's
754      changes.
755
7562018-04-19
757
758    - [BUGFIX] Add connection to Tickable Queue on stream write
759    - cmake: use MSVC variable instead of trying to detect
760    - engine: improve connection incref/decref logging
761    - stream: don't ignore errors that may occur on triggered flush
762    - connection: remove obsolete method
763    - engine: indicate connection as tickable if previous call went
764      over threshold
765
7662018-04-09
767
768    [API Change, OPTIMIZATION] Only process conns that need to be processed
769
770    The API is simplified: do not expose the user code to several
771    queues.  A "connection queue" is now an internal concept.
772    The user processes connections using the single function
773    lsquic_engine_process_conns().  When this function is called,
774    only those connections are processed that need to be processed.
775    A connection needs to be processed when:
776
777        1. New incoming packets have been fed to the connection.
778        2. User wants to read from a stream that is readable.
779        3. User wants to write to a stream that is writeable.
780        4. There are buffered packets that can be sent out.  (This
781           means that the user wrote to a stream outside of the
782           lsquic library callback.)
783        5. A control frame (such as BLOCKED) needs to be sent out.
784        6. A stream needs to be serviced or delayed stream needs to
785           be created.
786        7. An alarm rings.
787        8. Pacer timer expires.
788
789    To achieve this, the library places the connections into two
790    priority queues (min heaps):
791
792        1. Tickable Queue; and
793        2. Advisory Tick Time queue (ATTQ).
794
795    Each time lsquic_engine_process_conns() is called, the Tickable
796    Queue is emptied.  After the connections have been ticked, they are
797    queried again: if a connection is not being closed, it is placed
798    either in the Tickable Queue if it is ready to be ticked again or
799    it is placed in the Advisory Tick Time Queue.  It is assumed that
800    a connection always has at least one timer set (the idle alarm).
801
802    The connections in the Tickable Queue are arranged in the least
803    recently ticked order.  This lets connections that have been quiet
804    longer to get their packets scheduled first.
805
806    This change means that the library no longer needs to be ticked
807    periodically.  The user code can query the library when is the
808    next tick event and schedule it exactly.  When connections are
809    processed, only the tickable connections are processed, not *all*
810    the connections.  When there are no tick events, it means that no
811    timer event is necessary -- only the file descriptor READ event
812    is active.
813
814    The following are improvements and simplifications that have
815    been triggered:
816
817        - Queue of connections with incoming packets is gone.
818        - "Pending Read/Write Events" Queue is gone (along with its
819          history and progress checks).  This queue has become the
820          Tickable Queue.
821        - The connection hash no longer needs to track the connection
822          insertion order.
823
8242018-04-02
825
826    - [FEATURE] Windows support
827
828    - Reduce stack use -- outgoing packet batch is now allocated on the heap.
829
8302018-03-09
831
832    - [OPTIMIZATION] Merge series of ACKs if possible
833
834      Parsed single-range ACK frames (that is the majority of frames) are
835      saved in the connection and their processing is deferred until the
836      connection is ticked.  If several ACKs come in a series between
837      adjacent ticks, we check whether the latest ACK is a strict superset
838      of the saved ACK.  If it is, the older ACK is not processed.
839
840      If ACK frames can be merged, they are merged and only one of them is
841      either processed or saved.
842
843    - [OPTIMIZATION] Speed up ACK verification by simplifying send history.
844
845      Never generate a gap in the sent packet number sequence.  This reduces
846      the send history to a single number instead of potentially a series of
847      packet ranges and thereby speeds up ACK verification.
848
849      By default, detecting a gap in the send history is not fatal: only a
850      single warning is generated per connection.  The connection can continue
851      to operate even if the ACK verification code is not able to detect some
852      inconsistencies.
853
854    - [OPTIMIZATION] Rearrange the lsquic_send_ctl struct
855
856      The first part of struct lsquic_send_ctl now consists of members that
857      are used in lsquic_send_ctl_got_ack() (in the absense of packet loss,
858      which is the normal case).  To speed up reads and writes, we no longer
859      try to save space by using 8- and 16-bit integers.  Use regular integer
860      width for everything.
861
862    - [OPTIMIZATION] Cache size of sent packet.
863
864    - [OPTIMIZATION] Keep track of the largest ACKed in packet_out
865
866      Instead of parsing our own ACK frames when packet has been acked,
867      use the value saved in the packet_out structure when the ACK frame
868      was generated.
869
870    - [OPTIMIZATION] Take RTT sampling conditional out of ACK loop
871
872    - [OPTIMIZATION] ACK processing: only call clock_gettime() if needed
873
874    - [OPTIMIZATION] Several code-level optimizations to ACK processing.
875
876    - Fix: http_client: fix -I flag; switch assert() to abort()
877
8782018-02-26
879    - [API Change] lsquic_engine_connect() returns pointer to the connection
880      object.
881    - [API Change] Add lsquic_conn_get_engine() to get engine object from
882      connection object.
883    - [API Change] Add lsquic_conn_status() to query connection status.
884    - [API Change] Add add lsquic_conn_set_ctx().
885    - [API Change] Add new timestamp format, e.g. 2017-03-21 13:43:46.671345
886    - [OPTIMIZATION] Process handshake STREAM frames as soon as packet
887      arrives.
888    - [OPTIMIZATION] Do not compile expensive send controller sanity check
889      by default.
890    - [OPTIMIZATION] Add fast path to gquic_be_gen_reg_pkt_header.
891    - [OPTIMIZATION] Only make squeeze function call if necessary.
892    - [OPTIMIZATION] Speed up Q039 ACK frame parsing.
893    - [OPTIMIZATION] Fit most used elements of packet_out into first 64 bytes.
894    - [OPTIMIZATION] Keep track of scheduled bytes instead of calculating.
895    - [OPTIMIZATION] Prefetch next unacked packet when processing ACK.
896    - [OPTIMIZATION] Leverage fact that ACK ranges and unacked list are.
897      ordered.
898    - [OPTIMIZATION] Reduce function pointer use for STREAM frame generation
899    - Fix: reset incoming streams that arrive after we send GOAWAY.
900    - Fix: delay client on_new_conn() call until connection is fully set up.
901    - Fixes to buffered packets logic: splitting, STREAM frame elision.
902    - Fix: do not dispatch on_write callback if no packets are available.
903    - Fix WINDOW_UPDATE send and resend logic.
904    - Fix STREAM frame extension code.
905    - Fix: Drop unflushed data when stream is reset.
906    - Switch to tracking CWND using bytes rather than packets.
907    - Fix TCP friendly adjustment in cubic.
908    - Fix: do not generate invalid STOP_WAITING frames during high packet
909      loss.
910    - Pacer fixes.
911
9122017-12-18
913
914    - Fix: better follow cubic curve after idle period
915    - Fix: add missing parts to outgoing packet splitting code
916    - Fix: compilation using gcc 4.8.4
917
9182017-10-31
919
920    - Add APIs.txt -- describes LSQUIC APIs
921
9222017-10-31
923
924    - [API Change] Sendfile-like functionality is gone.  The stream no
925      longer opens files and deals with file descriptors.  (Among other
926      things, this makes the code more portable.)  Three writing functions
927      are provided:
928
929        lsquic_stream_write
930        lsquic_stream_writev
931        lsquic_stream_writef    (NEW)
932
933      lsquic_stream_writef() is given an abstract reader that has function
934      pointers for size() and read() functions which the user can implement.
935      This is the most flexible way.  lsquic_stream_write() and
936      lsquic_stream_writev() are now both implemented as wrappers around
937      lsquic_stream_writef().
938
939    - [OPTIMIZATION] When writing to stream, be it within or without the
940      on_write() callback, place data directly into packet buffer,
941      bypassing auxiliary data structures.  This reduces amount of memory
942      required, for the amount of data that can be written is limited
943      by the congestion window.
944
945      To support writes outside the on_write() callback, we keep N
946      outgoing packet buffers per connection which can be written to
947      by any stream.  One half of these are reserved for the highest
948      priority stream(s), the other half for all other streams.  This way,
949      low-priority streams cannot write instead of high-priority streams
950      and, on the other hand, low-priority streams get a chance to send
951      their packets out.
952
953      The algorithm is as follows:
954
955      - When user writes to stream outside of the callback:
956        - If this is the highest priority stream, place it onto the
957          reserved N/2 queue or fail.
958            (The actual size of this queue is dynamic -- MAX(N/2, CWND) --
959             rather than N/2, allowing high-priority streams to write as
960             much as can be sent.)
961        - If the stream is not the highest priority, try to place the
962          data onto the reserved N/2 queue or fail.
963      - When tick occurs *and* more packets can be scheduled:
964        - Transfer packets from the high N/2 queue to the scheduled
965          queue.
966        - If more scheduling is allowed:
967          - Call on_write callbacks for highest-priority streams,
968            placing resulting packets directly onto the scheduled queue.
969        - If more scheduling is allowed:
970          - Transfer packets from the low N/2 queue to the scheduled
971            queue.
972        - If more scheduling is allowed:
973          - Call on_write callbacks for non-highest-priority streams,
974            placing resulting packets directly onto the scheduled queue
975
976      The number N is currently 20, but it could be varied based on
977      resource usage.
978
979    - If stream is created due to incoming headers, make headers readable
980      from on_new.
981
982    - Outgoing packets are no longer marked non-writeable to prevent placing
983      more than one STREAM frame from the same stream into a single packet.
984      This property is maintained via code flow and an explicit check.
985      Packets for stream data are allocated using a special function.
986
987    - STREAM frame elision is cheaper, as we only perform it if a reset
988      stream has outgoing packets referencing it.
989
990    - lsquic_packet_out_t is smaller, as stream_rec elements are now
991      inside a union.
992
9932017-10-12
994
995    - Do not send RST_STREAM when stream is closed for reading
996    - Raise maximum header size from 4K to 64K
997    - Check header name and value lengths against maximum imposed by HPACK
998    - Fix NULL dereference in stream flow controller
999
10002017-10-09
1001
1002    - Hide handshake implementation behind a set of function pointers
1003    - Use monotonically increasing clock
1004    - Make sure that retx delay is not larger than the max of 60 seconds
1005
10062017-09-29
1007
1008    - A few fixes to code and README
1009
10102017-09-28
1011
1012    - Add support for Q041; drop support for Q040
1013
10142017-09-27
1015
1016    - Fix CMakeLists.txt: BoringSSL include and lib was mixed up
1017
10182017-09-26
1019
1020    - Add support for Mac OS
1021    - Add support for Raspberry Pi
1022    - Fix BoringSSL compilation: include <openssl/hmac.h> explicitly
1023
10242017-09-22
1025
1026    - Initial release
1027