This makes the behavior of HTTP/2 and HTTP/3 much more similar. In
particular, the HTTP/3 :authority pseudoheader is used to set the Host
header, instead of the virtual server. This is arguably less correct,
but it is consistent with the existing HTTP/2 behavior and unbreaks
users of PHP-FPM and other FastCGI applications. In the future, NGINX
could have a config option that caused :authority and Host to be treated
separately in both HTTP/2 and HTTP/3.
Fixes: #587Fixes: #256
Per RFC9110, HTTP field values never contain leading or trailing
whitespace. Strip all such whitespace from HTTP and HTTP field values.
The HTTP/1.x parser already stripped spaces but didn't strip tabs, so
change the parser to strip tabs as well. In HTTP/2+, the stripping is
done during validation. This requires modifying the value.
There are three ways to modify the value:
1. Modify the data in-place with memmove().
2. Move the data pointer to point to after the leading whitespace.
3. Allocate a new buffer and replace the data pointer.
Both HPACK and QPACK decompression make a copy of the data, but some
code might assume that the data pointer of a field value can safely be
passed to ngx_pfree(). Therefore, the first option is chosen. Existing
code ensures that header values are NUL-terminated, so the stripping
code NUL-pads header values to ensure that the stripped strings have at
least as many terminating NUL bytes as they did before being stripped.
The stripping code has been tested in a standalone program to make sure
that it works correctly, and it correctly strips leading and trailing
whitespace from a variety of strings. This code has also been tested
with real HTTP/3 requests from Cloudflare's h3i tool.
Fixes: #187Fixes: #598
The header validation required by HTTP/2 and HTTP/3 is identical, so use
a common function for both. This will make it easier to add additional
validation in the future. Move the function to ngx_http_parse.c so that
it can share code with the HTTP/1.x parser in the future.
No functional change intended.
Previously a decoder stream was created on demand for sending Section
Acknowledgement, Stream Cancellation and Insert Count Increment. If conditions
for sending any of these instructions never happen, a decoder stream is not
created at all. These conditions include client not using the dynamic table and
no streams abandoned by server (RFC 9204, Section 2.2.2.2). However RFC 9204,
Section 4.2 defines only one condition for not creating a decoder stream:
An endpoint MAY avoid creating a decoder stream if its decoder sets
the maximum capacity of the dynamic table to zero.
The change enables pre-creation of the decoder stream at HTTP/3 session
initialization if maximum dynamic table capacity is not zero. Note that this
value is currently hardcoded to 4096 bytes and is not configurable, so the
stream is now always created.
Also, the change fixes a potential stack overflow when creating a decoder
stream in ngx_http_v3_send_cancel_stream() while draining a request stream by
ngx_drain_connections(). Creating a decoder stream involves calling
ngx_get_connection(), which calls ngx_drain_connections(), which will drain the
same request stream again. If client's MAX_STREAMS for uni stream is high
enough, these recursive calls will continue until we run out of stack.
Otherwise, decoder stream creation will fail at some point and the request
stream connection will be drained. This may result in use-after-free, since
this connection could still be referenced up the stack.
Previously, a request body larger than declared in Content-Length resulted in
a 413 status code, because Content-Length was mistakenly used as the maximum
allowed request body, similar to client_max_body_size. Following the HTTP/3
specification, such requests are now rejected with the 400 error as malformed.
Now the session object is assigned to c->data while ngx_http_connection_t
object is referenced by its http_connection field, similar to
ngx_http_v2_connection_t and ngx_http_request_t.
The change allows to eliminate v3_session field from ngx_http_connection_t.
The field was under NGX_HTTP_V3 macro, which was a source of binary
compatibility problems when nginx/module is build with/without HTTP/3 support.
Postponing is essential since c->data should retain the reference to
ngx_http_connection_t object throughout QUIC handshake, because SSL callbacks
ngx_http_ssl_servername() and ngx_http_ssl_alpn_select() rely on this.
Previously QUIC did not have such parameter and handshake duration was
controlled by HTTP/3. However that required creating and storing HTTP/3
session on first client datagram. Apparently there's no convenient way to
store the session object until QUIC handshake is complete. In the followup
patches session creation will be postponed to init() callback.
Now "listen" directve has a new "quic" parameter which enables QUIC protocol
for the address. Further, to enable HTTP/3, a new directive "http3" is
introduced. The hq-interop protocol is enabled by "http3_hq" as before.
Now application protocol is chosen by ALPN.
Previously used "http3" parameter of "listen" is deprecated.
Previously, there was no timeout for a request stream blocked on insert count,
which could result in infinite wait. Now client_header_timeout is set when
stream is first blocked.
Previously, start_time wasn't set for a new stream.
The fix is to derive it from the parent connection.
Also it's used to simplify tracking keepalive_time.
Previously, keepalive timer was deleted in ngx_http_v3_wait_request_handler()
and set in request cleanup handler. This worked for HTTP/3 connections, but not
for hq connections. Now keepalive timer is deleted in
ngx_http_v3_init_request_stream() and set in connection cleanup handler,
which works both for HTTP/3 and hq.
It's called after handshake completion or prior to the first early data stream
creation. The callback should initialize application-level data before
creating streams.
HTTP/3 callback implementation sets keepalive timer and sends SETTINGS.
Also, this allows to limit max handshake time in ngx_http_v3_init_stream().
Now main QUIC connection for HTTP/3 always has c->idle flag set. This allows
the connection to receive worker shutdown notification. It is passed to
application level via a new conf->shutdown() callback.
The HTTP/3 shutdown callback sends GOAWAY to client and gracefully shuts down
the QUIC connection.
Previously, HTTP/3 stream connection didn't inherit the servername regex
from the main QUIC connection saved when processing SNI and using regular
expressions in server names. As a result, it didn't execute to set regex
captures when choosing the virtual server while parsing HTTP/3 headers.
When client DATA frame header and its content come in different QUIC packets,
it may happen that only the header is processed by the first
ngx_http_v3_request_body_filter() call. In this case an empty request body
buffer is added to r->request_body->bufs, which is later reused in a
subsequent ngx_http_v3_request_body_filter() call without being removed from
the body chain. As a result, rb->request_body->bufs ends up with two copies of
the same buffer.
The fix is to avoid adding empty request body buffers to r->request_body->bufs.
Directives that set transport parameters are removed from the configuration.
Corresponding values are derived from the quic configuration or initialized
to default. Whenever possible, quic configuration parameters are taken from
higher-level protocol settings, i.e. HTTP/3.
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.
