Motivation:
The send window size is currently fixed by a macro at compile time.
In order for users of the library to impact the send window size they
would have to change a macro at compile time. The window size may be dynamic
depending on the environment and deployment scheme. The library users
currently have no way to change this parameter.
Modifications:
Add a new optional callback method which is called before data is sent to
obtain the desired send window size. The callback return value will be
subject to a range check for the current session, stream, and settings
limits defined by flow control.
Result:
Library users have control over their send sizes.
Previously returning NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE from
on_header_callback moves input offset badly and it causes header
decompression error on the subsequent frames. This commit fix this
bug.
Previously we just assumed that if same settings ID is found in
SETTINGS, it is enough to process last seen entry. But it turns out
it is not enough for SETTINGS_HEADER_TABLE_SIZE. If we have 0 and
4096 for SETTINGS_HEADER_TABLE_SIZE in one SETTINGS, we must first
shrink dynamic table to 0 and then enlarge it to 4096. This means
that we have to remember the minimum value and last value.
Previously in inflater we reserve new ringbuffer when table size is
changed. This may be potentially a problem if new table size is very
large number. When inflater is not used directly by application, this
is not a problem because application can choose the buffer size. On
the other hand, if application uses inflater directly and it does not
have control of new buffer size (e.g., protocol dissector), then we
just fail to allocate large buffer in
nghttp2_hd_inflate_change_table_size() without actually use such huge
buffer. This change defers the actual allocation of buffer when it is
actually needed so that we will fail when it is absolutely needed.
We inherited gzip compression API from spdylay codebase. In spdylay,
the cost of having such API is almost free because spdylay requires
zlib for header compression. nghttp2 no longer uses gzip to header
compression. zlib dependency exists just for gzip compression API,
which is not an essential. So we decided to move gzip code to under
src and remove zlib dependency from libnghttp2 itself. As nghttp2
package, we depend on zlib to compile tools under src.
If stream with dpri value of no_data, we check any its descendant has
stream with dpri value of top. If so, we have to distribute of its
portion of weight to its descendants.
We need paddings regardless of payload and frame boundary to mitigate
certain attacks.
Since we handles CONTINUATION internally, we don't show FLAG_PAD_HIGH
and PAD_LOW flags of HEADERS in nghttp/nghttpd. We just show the
total paddings in HEADERS + CONTINUATION.
* Use 1 Huffman code table for both request and response
* Remove complicated deflater side table size management
* Add encoding context update
* Fix memory leak in inflater
Now previous padding options are removed and instead we added
select_padding_callback to select padding length for each frame
by application. If this callback is not implemented by application,
no padding is added.
This change also fixes the broken session_detect_idle_stream()
if stream_id is our side.
This stream inflater can inflate incoming header block in streaming
fashion. Currently, we buffer up single name/value pair, but we chose
far more smaller buffer size than HTTP/2 frame size.
nghttp2 library itself now accept octet header/value pairs,
completely not restricted by HTTP/1 header name/value rule.
The applications may impose restriction about them using
validators.
The NGHTTP2_ERR_PAUSE library error code is introduced to pause
the execution of nghttp2_session_mem_recv() when that error code
is returned from nghttp2_on_frame_recv_callback or
nghttp2_on_data_chunk_recv_callback. If this happens, the parameters
available for both callbacks are retained until the application
calls nghttp2_session_continue(). The application must retain
input bytes which was used to produce the frame.
After successful call of nghttp2_session_continue, the application
can continue to call nghttp2_session_mem_recv() to process
additional data.
This function is similar to nghttp2_submit_request and the
difference is it takes an array of nghttp2_nv as name/value pairs.
It is useful if name/value pairs is not NULL-terminated in the
application code.
Fix the bug that connection-level local window is not updated
for the data is the last part of the stream. For the stream
level window may ignore this, connection-level window must
be updated. Also this change fixes the bug that connection-level
window is not updated for the ignored DATA frames.
SPDY spec does not allow multiple empty header values in one header
field. This change makes out-going framer ignore such empty header
value if there is non-empty header value with the same name.
This change implements spdylay_map functions in iterative approach
instead of original recursive approach. The iterative version is
overall faster than recursive one. The traversal function
(spdylay_map_each) is slightly slower but it is not noticeable.
If resultant length of a frame exceeds the maximum value (which is
2**24 - 1 for SPDY/2 and 3), SPDYLAY_ERR_FRAME_TOO_LARGE is used to
indicate this error. This error will be notified by
on_ctrl_not_send_callback.
spdylay_npn_get_proto_list() returns a pointer to the supported SPDY
version list. The element of the list is spdylay_npn_proto struct. It
contains all SPDY version information this library supports. The
application can use this information to configure NPN protocol
offerings/selection.
We say the header block is invalid if at least one of the following
condition is true:
There are duplicate header names; or the header names are not
encoded in US-ASCII character set and not lower cased; or the
header name is zero-length string; or the header value contains
multiple in-sequence NUL bytes.
spdylay_frame_unpack_nv() returns SPDYLAY_ERR_INVALID_HEADER_BLOCK
if the unpacking suceeded but it found the header block is invalid.
This means that caller treats it as success, but do additional
processing for invalid header block if it wants.
The functions calling spdylay_frame_unpack_nv() also return
SPDYLAY_ERR_INVALID_HEADER_BLOCK.
Tatsuhiro Tsujikawa
Scott Mitchell