CHANGELOG revision c51ce338 
12017-10-31
2
3    - [API Change] Sendfile-like functionality is gone.  The stream no
4      longer opens files and deals with file descriptors.  (Among other
5      things, this makes the code more portable.)  Three writing functions
6      are provided:
7
8        lsquic_stream_write
9        lsquic_stream_writev
10        lsquic_stream_writef    (NEW)
11
12      lsquic_stream_writef() is given an abstract reader that has function
13      pointers for size() and read() functions which the user can implement.
14      This is the most flexible way.  lsquic_stream_write() and
15      lsquic_stream_writev() are now both implemented as wrappers around
16      lsquic_stream_writef().
17
18    - [OPTIMIZATION] When writing to stream, be it within or without the
19      on_write() callback, place data directly into packet buffer,
20      bypassing auxiliary data structures.  This reduces amount of memory
21      required, for the amount of data that can be written is limited
22      by the congestion window.
23
24      To support writes outside the on_write() callback, we keep N
25      outgoing packet buffers per connection which can be written to
26      by any stream.  One half of these are reserved for the highest
27      priority stream(s), the other half for all other streams.  This way,
28      low-priority streams cannot write instead of high-priority streams
29      and, on the other hand, low-priority streams get a chance to send
30      their packets out.
31
32      The algorithm is as follows:
33
34      - When user writes to stream outside of the callback:
35        - If this is the highest priority stream, place it onto the
36          reserved N/2 queue or fail.
37            (The actual size of this queue is dynamic -- MAX(N/2, CWND) --
38             rather than N/2, allowing high-priority streams to write as
39             much as can be sent.)
40        - If the stream is not the highest priority, try to place the
41          data onto the reserved N/2 queue or fail.
42      - When tick occurs *and* more packets can be scheduled:
43        - Transfer packets from the high N/2 queue to the scheduled
44          queue.
45        - If more scheduling is allowed:
46          - Call on_write callbacks for highest-priority streams,
47            placing resulting packets directly onto the scheduled queue.
48        - If more scheduling is allowed:
49          - Transfer packets from the low N/2 queue to the scheduled
50            queue.
51        - If more scheduling is allowed:
52          - Call on_write callbacks for non-highest-priority streams,
53            placing resulting packets directly onto the scheduled queue
54
55      The number N is currently 20, but it could be varied based on
56      resource usage.
57
58    - If stream is created due to incoming headers, make headers readable
59      from on_new.
60
61    - Outgoing packets are no longer marked non-writeable to prevent placing
62      more than one STREAM frame from the same stream into a single packet.
63      This property is maintained via code flow and an explicit check.
64      Packets for stream data are allocated using a special function.
65
66    - STREAM frame elision is cheaper, as we only perform it if a reset
67      stream has outgoing packets referencing it.
68
69    - lsquic_packet_out_t is smaller, as stream_rec elements are now
70      inside a union.
71
722017-10-12
73
74    - Do not send RST_STREAM when stream is closed for reading
75    - Raise maximum header size from 4K to 64K
76    - Check header name and value lengths against maximum imposed by HPACK
77    - Fix NULL dereference in stream flow controller
78
792017-10-09
80
81    - Hide handshake implementation behind a set of function pointers
82    - Use monotonically increasing clock
83    - Make sure that retx delay is not larger than the max of 60 seconds
84
852017-09-29
86
87    - A few fixes to code and README
88
892017-09-28
90
91    - Add support for Q041; drop support for Q040
92
932017-09-27
94
95    - Fix CMakeLists.txt: BoringSSL include and lib was mixed up
96
972017-09-26
98
99    - Add support for Mac OS
100    - Add support for Raspberry Pi
101    - Fix BoringSSL compilation: include <openssl/hmac.h> explicitly
102
1032017-09-22
104
105    - Initial release
106