As per quic-qpack-21:
When a stream is reset or reading is abandoned, the decoder emits a
Stream Cancellation instruction.
Previously the instruction was not sent. Now it's sent when closing QUIC
stream connection if dynamic table capacity is non-zero and eof was not
received from client. The latter condition means that a trailers section
may still be on its way from client and the stream needs to be cancelled.
A QUIC stream connection is treated as reusable until first bytes of request
arrive, which is also when the request object is now allocated. A connection
closed as a result of draining, is reset with the error code
H3_REQUEST_REJECTED. Such behavior is allowed by quic-http-34:
Once a request stream has been opened, the request MAY be cancelled
by either endpoint. Clients cancel requests if the response is no
longer of interest; servers cancel requests if they are unable to or
choose not to respond.
When the server cancels a request without performing any application
processing, the request is considered "rejected." The server SHOULD
abort its response stream with the error code H3_REQUEST_REJECTED.
The client can treat requests rejected by the server as though they had
never been sent at all, thereby allowing them to be retried later.
When an HTTP/3 function returns an error in context of a QUIC stream, it's
this function's responsibility now to finalize the entire QUIC connection
with the right code, if required. Previously, QUIC connection finalization
could be done both outside and inside such functions. The new rule follows
a similar rule for logging, leads to cleaner code, and allows to provide more
details about the error.
While here, a few error cases are no longer treated as fatal and QUIC connection
is no longer finalized in these cases. A few other cases now lead to
stream reset instead of connection finalization.
With this patch, all traffic over HTTP/3 bidi and uni streams is counted in
the h3c->total_bytes field, and payload traffic is counted in the
h3c->payload_bytes field. As long as total traffic is many times larger than
payload traffic, we consider this to be a flood.
Request header traffic is counted as if all fields are literal. Response
header traffic is counted as is.
Previously the counter was not incremented for HTTP/3 streams, but still
decremented in ngx_http_close_connection(). There are two solutions here, one
is to increment the counter for HTTP/3 streams, and the other one is not to
decrement the counter for HTTP/3 streams. The latter solution looks
inconsistent with ngx_stat_reading/ngx_stat_writing, which are incremented on a
per-request basis. The change adds ngx_stat_active increment for HTTP/3
request and push streams.
After receiving GOAWAY, client is not supposed to create new streams. However,
until client reads this frame, we allow it to create new streams, which are
gracefully rejected. To prevent client from abusing this algorithm, a new
limit is introduced. Upon reaching keepalive_requests * 2, server now closes
the entire QUIC connection claiming excessive load.
Renamed header -> field per quic-qpack naming convention, in particular:
- Header Field -> Field Line
- Header Block -> (Encoded) Field Section
- Without Name Reference -> With Literal Name
- Header Acknowledgement -> Section Acknowledgment
It's used instead of accessing c->quic->parent->data directly. Apart from being
simpler, it allows to change the way session is stored in the future by changing
the macro.
The function ngx_quic_shutdown_connection() waits until all non-cancelable
streams are closed, and then closes the connection. In HTTP/3 cancelable
streams are all unidirectional streams except push streams.
The function is called from HTTP/3 when client reaches keepalive_requests.
The structure is used to parse an HTTP/3 request. An object of this type is
added to ngx_http_request_t instead of h3_parse generic pointer.
Also, the new field is located outside of the request ephemeral zone to keep it
safe after request headers are parsed.
The change reduces diff to the default branch for
src/http/ngx_http_request_body.c.
Also, client Content-Length, if present, is now checked against the real body
size sent by client.
This function should be called at the end of an event handler to prepare the
event for the next handler call. Particularly, the "active" flag is set or
cleared depending on data availability.
With this call missing in one code path, read handler was not called again
after handling the initial part of the client request, if the request was too
big to fit into a single STREAM frame.
Now ngx_handle_read_event() is called in this code path. Also, read timer is
restarted.
A header with the name containing null, CR, LF, colon or uppercase characters,
is now considered an error. A header with the value containing null, CR or LF,
is also considered an error.
Also, header is considered invalid unless its name only contains lowercase
characters, digits, minus and optionally underscore. Such header can be
optionally ignored.
- :method, :path and :scheme are expected exactly once and not empty
- :method and :scheme character validation is added
- :authority cannot appear more than once
The filter is responsible for creating HTTP/3 response header and body.
The change removes differences to the default branch for
ngx_http_chunked_filter_module and ngx_http_header_filter_module.
As per HTTP/3 draft 29, section 4.1:
Frames of unknown types (Section 9), including reserved frames
(Section 7.2.8) MAY be sent on a request or push stream before,
after, or interleaved with other frames described in this section.
Also, trailers frame is now used as an indication of the request body end.
While for HTTP/1 unexpected eof always means an error, for HTTP/3 an eof right
after a DATA frame end means the end of the request body. For this reason,
since adding HTTP/3 support, eof no longer produced an error right after recv()
but was passed to filters which would make a decision. This decision was made
in ngx_http_parse_chunked() and ngx_http_v3_parse_request_body() based on the
b->last_buf flag.
Now that since 0f7f1a509113 (1.19.2) rb->chunked->length is a lower threshold
for the expected number of bytes, it can be set to zero to indicate that more
bytes may or may not follow. Now it's possible to move the check for eof from
parser functions to ngx_http_request_body_chunked_filter() and clean up the
parsing code.
Also, in the default branch, in case of eof, the following three things
happened, which were replaced with returning NGX_ERROR while implementing
HTTP/3:
- "client prematurely closed connection" message was logged
- c->error flag was set
- NGX_HTTP_BAD_REQUEST was returned
The change brings back this behavior for HTTP/1 as well as HTTP/3.
Previously errors led only to closing streams.
To simplify closing QUIC connection from a QUIC stream context, new macro
ngx_http_v3_finalize_connection() is introduced. It calls
ngx_quic_finalize_connection() for the parent connection.
Previously dynamic table was not functional because of zero limit on its size
set by default. Now the following changes enable it:
- new directives to set SETTINGS_QPACK_MAX_TABLE_CAPACITY and
SETTINGS_QPACK_BLOCKED_STREAMS
- send settings with SETTINGS_QPACK_MAX_TABLE_CAPACITY and
SETTINGS_QPACK_BLOCKED_STREAMS to the client
- send Insert Count Increment to the client
- send Header Acknowledgement to the client
- evict old dynamic table entries on overflow
- decode Required Insert Count from client
- block stream if Required Insert Count is not reached
Preserving pointers within the client buffer is not needed for HTTP/3 because
all data is either allocated from pool or static. Unlike with HTTP/1, data
typically cannot be referenced directly within the client buffer. Trying to
preserve NULLs or external pointers lead to broken pointers.
Also, reverted changes in ngx_http_alloc_large_header_buffer() not relevant
for HTTP/3 to minimize diff to mainstream.
New field r->parse_start is introduced to substitute r->request_start and
r->header_name_start for request length accounting. These fields only work for
this purpose in HTTP/1 because HTTP/1 request line and header line start with
these values.
Also, error logging is now fixed to output the right part of the request.
As per HTTP/3 draft 27, a request or response containing uppercase header
field names MUST be treated as malformed. Also, existing rules applied
when parsing HTTP/1 header names are also applied to HTTP/3 header names:
- null character is not allowed
- underscore character may or may not be treated as invalid depending on the
value of "underscores_in_headers"
- all non-alphanumeric characters with the exception of '-' are treated as
invalid
Also, the r->locase_header field is now filled while parsing an HTTP/3
header.
Error logging for invalid headers is fixed as well.
The first one parses pseudo-headers and is analagous to the request line
parser in HTTP/1. The second one parses regular headers and is analogous to
the header parser in HTTP/1.
Additionally, error handling of client passing malformed uri is now fixed.
