Previously, in server side, we used closed streams to detect the error
that the misbehaving client sends a frame on the incoming stream it
explicitly closed. With this commit, we make a further step, and
detect one more error case. Since we retain closed streams as long as
the sum of its size and the number of opened streams are equal or less
than max concurrent streams, we can safely say that if we get a frame
which is sent on the stream that is not found in either closed or
opened stream, it is already closed or has not existed. Then we can
send GOAWAY.
The previous code shrinks closed streams when we closed another
stream, but now it is removed. It is enough to adjust closed streams
when new incoming stream is created.
While creating this commit, we noticed that
NGHTTP2_INITIAL_MAX_CONCURRENT_STREAMS is defined as INT32_MAX. But
since SETTINGS can contain value up to UINT32_MAX, it is not enough.
However, since the stream ID space is limited to INT32_MAX, it is high
enough. We could keep this value, but this time we deprecate
NGHTTP2_INITIAL_MAX_CONCURRENT_STREAMS macro. While it is in public
header, the effect of deprecating it is negligible because of the
reason we wrote above, and usually application sets much smaller value
(say, 100) as SETTINGS_MAX_CONCURRENT_STREAMS.
https://tools.ietf.org/html/rfc7540#section-5.3.3 explains how to
transform dependency tree to avoid circular dependency. Previously,
we wrongly always moved the dependent stream under the root stream.
The correct destination is the parent stream of the stream to
reprioritize. This commit fixes this bug.
nghttp2_on_invalid_header_callback is similar to
nghttp2_on_header_callback, but the former is only called when the
invalid header field is received which is silently ignored when the
callback is not set. With this callback, application inspects the
incoming invalid field, and it also can reset stream from this
callback by returning NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE, or using
nghttp2_submit_rst_stream() directly with the error code of choice.
We also added nghttp2_on_invalid_header_callback2, which uses
reference counted header fields.
This function sets the maximum length of header block (a set of header
fields per HEADERS frame) to send. The length of given set of header
fields is calculated using nghttp2_hd_deflate_bound(). Previously,
this is hard-coded, and is 64KiB.
This option prevents the nghttp2 library from sending PING frame with
ACK flag set in the reply to incoming PING frame. To allow the
application to send PING with ACK flag set, nghttp2_submit_ping() now
recognizes NGHTTP2_FLAG_PING in its flags parameter.
Since v0.6.2-7-g1d138ac ("Unify DATA and other frames in
nghttp2_outbound_item and save malloc()"), the macros are unused and the
builds fails on -Werror=unused-macros.
Disallow request from server, and response from client respectively.
When the violation is detected, return NGHTTP2_ERR_PROTO from
nghttp2_submit_request, nghttp2_submit_response,
nghttp2_submit_headers.
We also did some refactoring, and now self-dependency detection is
placed where it is only required.
Previously, we use session->next_stream_id to detect that given stream
ID was idle or not. But this was suboptimal, since it was updated
when stream ID was assigned, and it did not necessarily mean that it
actually has been sent to the peer. Now we introduced
session->sent_stream_id, which only updated when HEADERS/PUSH_PROMISE
has sent. Using sent_stream_id instead of next_stream_id tightens
idle stream detection, and misbehaved peer which sends frame with
stream ID that has not been generated.
This commit also overhauls test code which involves opening streams.
Now we have some wrapper functions for nghttp2_session_open_stream()
which also take care of updating next_stream_id and
last_recv_stream_id. They are crucial for some tests.
Return NGHTTP2_ERR_INVALID_ARGUMENT from nghttp2_submit_headers() if
given stream ID and pri_spec->stream_id are the same (thus trying to
depend on itself).
Also return NGHTTP2_ERR_INVALID_ARGUMENT from nghttp2_submit_request()
and nghttp2_submit_headers() with stream_id == 1, when new stream ID
equals to pri_spec->stream_id.
Previously, these cases are not checked, and just sent to peer.
With the presence of idle stream related API (e.g.,
nghttp2_create_idle_stream()), it is more predictable for client to
create idle streams with its dependency to another idle stream.
Previously, we didn't create complete parent idle stream in this case.
Now we create idle streams as we do on server side.
Previously, stream object for pushed resource was not created during
nghttp2_submit_push_promise(). It was created just before
nghttp2_before_frame_send_callback was called for that PUSH_PROMISE
frame. This means that application could not call
nghttp2_submit_response for the pushed resource before
nghttp2_before_frame_send_callback was called. This could be solved
by callback chaining, but for web server with back pressure from
backend stream, it is a bit unnecessarily hard to use.
This commit changes nghttp2_submit_push_promise() behaviour so that
stream object is created during that call. It makes application call
nghttp2_submit_response right after successful
nghttp2_submit_push_promise call.
Previously, nghttp2_session_end_request_headers_received assumes
stream is still writable (in other words, local endpoint has not sent
END_STREAM). But this assumption is false, because application can
send response in nghttp2_on_begin_frame_callback. Probably, this
assumption was made before the callback was introduced. This commit
addresses this issue. Since all
nghttp2_session_end_*_headers_received functions are identical, we
refactored them into one function.
Previously, nghttp2_session_find_stream(session, 0) returned NULL
despite the fact that documentation said that it should return root
stream. Now it is corrected, and it returns root stream as
documented.
It has no usecase at the moment. It is most likely that applications
know the flags when it submitted extension frame, no need to modify it
later. Possibly feature bloat.
Tatsuhiro Tsujikawa
Peter Wu