Since the following patch, app_ops layer is now responsible to report
that HTX block was the last transmitted so that FIN STREAM can be set.
This is mandatory to properly support HTTP 1xx interim responses.
f349df44b4e21d8bf9b575a0aa869056a2ebaa58
MINOR: qmux: change API for snd_buf FIN transmission
This change was correctly implemented in HTTP/3 code, however an issue
appeared on hq-interop transcoder in case zero-copy DATA transfer is
performed when HTX buffer is swapped. If this occured during the
transfer of the last HTX block, EOM is not detected and thus STREAM FIN
is never set.
Most of the times, QMUX shut callback is called immediately after. This
results in an emission of a RESET_STREAM to the client, which prevents
the data transfer.
To fix this, use the same method as HTTP/3 : HTX EOM flag status is
checked before any transfer, thus preserving it even after a zero-copy.
Criticity of this bug is low as hq-interop is experimental and is mostly
used for interop testing.
This should fix github issue #3038.
This patch must be backported wherever the above one is.
Previous patches have fixes interim response encoding via
h3_resp_headers_send(). However, it is still necessary to adjust h3
layer state-machine so that several successive HTTP responses are
accepted for a single stream.
Prior to this, QMUX was responsible to decree that the final HTX message
was encoded so that FIN stream can be emitted. However, with interim
response, MUX is in fact unable to properly determine this. As such,
this is the responsibility of the application protocol layer. To reflect
this, app_ops snd_buf callback is modified so that a new output argument
<fin> is added to it.
Note that for now this commit does not bring any functional change.
However, it will be necessary for the following patch. As such, it
should be backported prior to it to every versions as necessary.
On backend side, HTTP/0.9 response body is copied into stream data HTX
buffer. Properly handle the case where the HTX out buffer space is too
small. Only copy a partial copy of the HTTP response. Transcoding will
be restarted when new room is available.
Implement transcoding of a HTX request into HTTP/0.9. This protocol is a
simplified version of HTTP. Request only supports GET method without any
header. As such, only a request line is written during snd_buf
operation.
Implement transcoding of a HTTP/0.9 response into a HTX message.
HTTP/0.9 is a really simple substract of HTTP spec. The response does
not have any status line and is contains only the payload body. Response
is finished when the underlying connection/stream is closed.
A status line is generated to be compliant with HTX. This is performed
on the first invokation of rcv_buf for the current stream. Status code
is set to 200. Payload body if present is then copied using
htx_add_data().
Complete document for rcv_buf/snd_buf operations. In particular, return
value is now explicitely defined. For H3 layer, associated functions
documentation is also extended.
Move general function to check if a stream is uni or bidirectional from
QUIC MUX to quic_utils module. This should prevent unnecessary include
of QUIC MUX header file in other sources.
Previously, a function qcs_http_handle_standalone_fin() was implemented
to handle a received standalone FIN, bypassing app_ops layer decoding.
However, this was removed as app_ops layer interaction is necessary. For
example, HTTP/3 checks that FIN is never sent on the control uni stream.
This patch reintroduces qcs_http_handle_standalone_fin(), albeit in a
slightly diminished version. Most importantly, it is now the
responsibility of the app_ops layer itself to use it, to avoid the
shortcoming described above.
The main objective of this patch is to be able to support standalone FIN
in HTTP/0.9 layer. This is easily done via the reintroduction of
qcs_http_handle_standalone_fin() usage. This will be useful to perform
testing, as standalone FIN is a corner case which can easily be broken.
HTTP/0.9 parser was recently updated to support truncated requests in
rcv_buf operation. However, this caused a leak as input buffer is
allocated early.
In fact, the leak was already present in case of fatal errors. Fix this
by first delaying buffer allocation, so that initial checks are
performed before. Then, ensure that buffer is released in case of a
latter error.
This is considered as minor, as HTTP/0.9 is reserved for experiment and
QUIC interop usages.
This should be backported up to 2.6.
Extends HTTP/0.9 layer to be able to deal with incomplete requests.
Instead of an error, 0 is returned. Thus, instead of a stream closure.
QUIC-MUX may retry rcv_buf operation later if more data is received,
similarly to HTTP/3 layer.
Note that HTTP/0.9 is only used for testing and interop purpose. As
such, this limitation is not considered as a bug. It is probably not
worth to backport it.
A recent fix was introduced to ensure that a streamdesc instance won't
be attached to an already completed QCS which is eligible to purging.
This was performed by skipping application protocol decoding if a QCS is
in such a state. Here is the patch responsible for this change.
caf60ac696a29799631a76beb16d0072f65eef12
BUG/MEDIUM: mux-quic: do not attach on already closed stream
However, this is too restrictive, in particular for unidirection stream
where no streamdesc is never attached. To fix this behavior, first
qcs_attach_sc() API has been modified. Instead of returning a streamdesc
instance, it returns either 0 on success or a negative error code.
There should be no functional changes with this patch. It is only to be
able to extend qcs_attach_sc() with the possibility of skipping
streamdesc instantiation while still keeping a success return value.
This should be backported wherever the above patch has been merged. For
the record, it was scheduled for immediate backport on 3.1, plus merging
on older releases up to 2.8 after a period of observation.
Recently, an issue was found with QUIC zero-copy forwarding on 3.0
version. A desynchronization could occur internally in QCS Tx bytes
counters which would cause a BUG_ON() crash on qcs_destroy() when the
stream is detached.
It was silently fixed in version 3.1 by the following patch. As it was
considered as an optimization, it was not scheduled yet for backport.
6697e87ae5e1f569dc87cf690b5ecfc049c4aab0
MINOR: mux-quic: Don't send an emtpy H3 DATA frame during zero-copy forwarding
This mistake has been caused due to some counter-intuitive manipulation
in QUIC zero-copy implementation. Try to streamline this in QUIC MUX
done_ff callback and its application protocol counterpart. Especially
for values exchanged between MUX and application on one side, and MUX
and stconn layer as done_fastfwd return value.
First, application done_ff callback now returns the length of the wholly
encoded frame. For HTTP/3, it means header length + payload length h3
frame. This value can then be reused as qcc_send_stream() argument to
increase QCS Tx soft offset.
As previously, special care has been taken to ensure that QUIC MUX
done_ff only return the transferred data bytes. Thus, any extra offset
for HTTP/3 header is properly excluded. This is mandatory for stconn
layer to consider the transfer has completed.
Secondly, remove duplicated code in application done_ff to reset iobuf
info. This is now factorize in QUIC MUX done_ff itself.
This patch is related to github issue #2678.
This patch extends qc_stream_desc API to be able to allocate small
buffers. QUIC MUX API is similarly updated as ultimatly each application
protocol is responsible to choose between a default or a smaller buffer.
Internally, the type of allocated buffer is remembered via qc_stream_buf
instance. This is mandatory to ensure that the buffer is released in the
correct pool, in particular as small and standard buffers can be
configured with the same size.
This commit is purely an API change. For the moment, small buffers are
not used. This will changed in a dedicated patch.
The goal is to indicate how critical the allocation is, between the
least one (growing an existing buffer ring) and the topmost one (boot
time allocation for the life of the process).
The 3 tcp-based muxes (h1, h2, fcgi) use a common allocation function
to try to allocate otherwise subscribe. There's currently no distinction
of direction nor part that tries to allocate, and this should be revisited
to improve this situation, particularly when we consider that mux-h2 can
reduce its Tx allocations if needed.
For now, 4 main levels are planned, to translate how the data travels
inside haproxy from a producer to a consumer:
- MUX_RX: buffer used to receive data from the OS
- SE_RX: buffer used to place a transformation of the RX data for
a mux, or to produce a response for an applet
- CHANNEL: the channel buffer for sync recv
- MUX_TX: buffer used to transfer data from the channel to the outside,
generally a mux but there can be a few specificities (e.g.
http client's response buffer passed to the application,
which also gets a transformation of the channel data).
The other levels are a bit different in that they don't strictly need to
allocate for the first two ones, or they're permanent for the last one
(used by compression).
This commit is a direct follow-up on the major rearchitecture of send
buffering. This patch implements the proper handling of connection pool
buffer temporary exhaustion.
The first step is to be able to differentiate a fatal allocation error
from a temporary pool exhaustion. This is done via a new output argument
on qcc_get_stream_txbuf(). For a fatal error, application protocol layer
will schedule the immediate connection closing. For a pool exhaustion,
QCC is flagged with QC_CF_CONN_FULL and stream sending process is
interrupted. QCS instance is also registered in a new list
<qcc.buf_wait_list>.
A new connection buffer can become available when all ACKs are received
for an older buffer. This process is taken in charge by quic-conn layer.
It uses qcc_notify_buf() function to clear QC_CF_CONN_FULL and to wake
up every streams registered on buf_wait_list to resume sending process.
This commit is a direct follow-up on the major rearchitecture of send
buffering. It allows application protocol to react if current QCS
sending buffer space is too small. In this case, the buffer can be
released to the quic-conn layer. This allows to allocate a new QCS
buffer and retry HTX parsing, unless connection buffer pool is already
depleted.
A new function qcc_release_stream_txbuf() serves as API for app protocol
to release the QCS sending buffer. This operation fails if there is
unsent data in it. In this case, MUX has to keep it to finalize transfer
of unsent data to quic-conn layer. QCS is thus flagged with
QC_SF_BLK_MROOM to interrupt snd_buf operation.
When all data are sent to the quic-conn layer, QC_SF_BLK_MROOM is
cleared via qcc_streams_sent_done() and stream layer is woken up to
restart snd_buf.
Note that a new function qcc_stream_can_send() has been defined. It
allows app proto to check if sending is currently blocked for the
current QCS. For now, it checks QC_SF_BLK_MROOM flag. However, it will
be extended to other conditions with the following patches.
Previously, QUIC MUX sending was implemented with data transfered along
two different buffer instances per stream.
The first QCS buffer was used for HTX blocks conversion into H3 (or
other application protocol) during snd_buf stream callback. QCS instance
is then registered for sending via qcc_io_cb().
For each sending QCS, data memcpy is performed from the first to a
secondary buffer. A STREAM frame is produced for each QCS based on the
content of their secondary buffer.
This model is useful for QUIC MUX which has a major difference with
other muxes : data must be preserved longer, even after sent to the
lower layer. Data references is shared with quic-conn layer which
implements retransmission and data deletion on ACK reception.
This double buffering stages was the first model implemented and remains
active until today. One of its major drawbacks is that it requires
memcpy invocation for every data transferred between the two buffers.
Another important drawback is that the first buffer was is allocated by
each QCS individually without restriction. On the other hand, secondary
buffers are accounted for the connection. A bottleneck can appear if
secondary buffer pool is exhausted, causing unnecessary haproxy
buffering.
The purpose of this commit is to completely break this model. The first
buffer instance is removed. Now, application protocols will directly
allocate buffer from qc_stream_desc layer. This removes completely the
memcpy invocation.
This commit has a lot of code modifications. The most obvious one is the
removal of <qcs.tx.buf> field. Now, qcc_get_stream_txbuf() returns a
buffer instance from qc_stream_desc layer. qcs_xfer_data() which was
responsible for the memcpy between the two buffers is also completely
removed. Offset fields of QCS and QCC are now incremented directly by
qcc_send_stream(). These values are used as boundary with flow control
real offset to delimit the STREAM frames built.
As this change has a big impact on the code, this commit is only the
first part to fully support single buffer emission. For the moment, some
limitations are reintroduced and will be fixed in the next patches :
* on snd_buf if QCS sent buffer in used has room but not enough for the
application protocol to store its content
* on snd_buf if QCS sent buffer is NULL and allocation cannot succeeds
due to connection pool exhaustion
One final important aspect is that extra care is necessary now in
snd_buf callback. The same buffer instance is referenced by both the
stream and quic-conn layer. As such, some operation such as realign
cannot be done anymore freely.
Similarly to H3, hq-interop now uses zero-copy when dealing with a HTX
message with only a single data block. Exchange HTX and QCS buffer, and
use the HTX data block for HTTP payload. This is only possible if QCS
buffer is empty. Contrary to HTTP/3, no extra frame header is needed
before transferring HTTP payload.
hq-interop is only implemented for testing purpose so this change should
not be noticeable by users. However, it will be useful to be able to
test zero-copy transfer on QUIC interop testing.
When dealing with HTTP/1 responses without Content-Length nor chunked
encoding, flag QC_SF_UNKNOWN_PL_LENGTH is set on QCS. This prevent the
emission of a RESET_STREAM on shutw, instead resorting to a proper FIN
emission.
This code was duplicated both in H3 and hq-interop. Move it in common
qcs_http_snd_buf() to factorize it.
qcc_app_ops is a set of callbacks used to unify application protocol
running over QUIC. This commit introduces some changes to clarify its
API :
* write simple comment to reflect each callback purpose
* rename decode_qcs to rcv_buf as this name is more common and is
similar to already existing snd_buf
* finalize is moved up as it is used during connection init stage
All these changes are ported to HTTP/3 layer. Also function comments
have been extended to highlight HTTP/3 special characteristics.
This function is similar to the previous one, but this time for QCS
sending buffer.
Previously, each application layer redefine their own version of
mux_get_buf() which was used to allocate <qcs.tx.buf>. Unify it under a
single function renamed qcc_get_stream_txbuf().
Implement callback for fast forwarding for hq-interop.
This change should not be considered as functionally important. Indeed,
HTTP/0.9 is reserved for QUIC interop testing and should not be used
outside of it. However, implementing fast forwarding in this context is
useful as this will allow to test MUX code sections for fast forward via
QUIC interop.
When possible, we try send DATA frame without copying data. To do so, we
swap the input buffer with QCS tx buffer. It is only possible iff:
* There is only one HTX block of data at the beginning of the message
* Amount of data to send is equal to the size of the HTX data block
* The QCS tx buffer is empty
In this case, both buffers are swapped. The frame metadata are written at
the begining of the buffer, before data and where the HTX structure is
stored.
hq-interop should be limited for QUIC testing. As such, its code should
be kept plain simple and not implement too many things.
This patch fixes issues which may cause rare QUIC interop failures :
- remove some unneeded BUG_ON() as parser should not be too strict
- remove support of partial message parsing
- ensure buffer data does not wrap as it was not properly handled. In
any case, this should never happen as only a single message will be
stored for each qcs buffer.
This should be backported up to 2.6.
This patch is similar to the previous one but for QUIC mux functions
used inside the mux code itself or application layer. Replace all
occurences of qc_* prefix by qcc_* or qcs_*. This should help to better
differentiate code between quic_conn and MUX.
This should be backported up to 2.7.
When a full message is received for a stream, MUX is responsible to set
EOI flag. This was done through rcv_buf stream callback by checking if
QCS HTX buffer contained the EOM flag.
This is not correct for HTTP without body. In this case, QCS HTX buffer
is never used. Only a local HTX buffer is used to transfer headers just
as stream endpoint is created. As such, EOI is never transmitted to the
upper layer.
If the transfer occur without any issue, this does not seem to cause any
problem. However, in case the transfer is aborted, the stream is never
released which cause a memory leak and prevent the process soft-stop.
To fix this, also check if EOM is put by application layer during
headers conversion. If true, this is transferred through a new argument
to qc_attach_sc() MUX function which is responsible to set the EOI flag.
This issue was reproduced using h2load with hundred of connections.
h2load is interrupted with a SIGINT which causes streams to never be
closed on haproxy side.
This should be backported up to 2.6.
Remove QUIC MUX function qcs_http_handle_standalone_fin(). The purpose
of this function was only used when receiving an empty STREAM frame with
FIN bit. Besides, it was called by each application protocol which could
have different approach and render the function purpose unclear.
Invocation of qcs_http_handle_standalone_fin() have been replaced by
explicit code in both H3 and HTTP/0.9 module. In the process, use
htx_set_eom() to reliably put EOM on the HTX message.
This should be backported up to 2.7, along with the previous patch which
introduced htx_set_eom().
Properly handle a STREAM frame with no data but the FIN bit set at the
application layer. H3 and hq-interop decode_qcs() callback have been
adjusted to not return early in this case.
If the FIN bit is accepted, a HTX EOM must be inserted for the upper
stream layer. If the FIN is rejected because the stream cannot be
closed, a proper CONNECTION_CLOSE error will be triggered.
A new utility function qcs_http_handle_standalone_fin() has been
implemented in the qmux_http module. This allows to simply add the HTX
EOM on qcs HTX buffer. If the HTX buffer is empty, a EOT is first added
to ensure it will be transmitted above.
This commit will allow to properly handle FIN notify through an empty
STREAM frame. However, it is not sufficient as currently qcc_recv() skip
the decode_qcs() invocation when the offset is already received. This
will be fixed in the next commit.
This should be backported up to 2.6 along with the next patch.
Factorize common code between h3 and hq-interop snd_buf operation. This
is inserted in MUX QUIC snd_buf own callback.
The h3/hq-interop API has been adjusted to directly receive a HTX
message instead of a plain buf. This led to extracting part of MUX QUIC
snd_buf in qmux_http module.
This should be backported up to 2.6.
Small cleanup on snd_buf for application protocol layer.
* do not export h3_snd_buf
* replace stconn by a qcs argument. This is better as h3/hq-interop only
uses the qcs instance.
This should be backported up to 2.6.
Implement http-request timeout for QUIC MUX. It is used when the
connection is opened and is triggered if no HTTP request is received in
time. By HTTP request we mean at least a QUIC stream with a full header
section. Then qcs instance is attached to a sedesc and upper layer is
then responsible to wait for the rest of the request.
This timeout is also used when new QUIC streams are opened during the
connection lifetime to wait for full HTTP request on them. As it's
possible to demux multiple streams in parallel with QUIC, each waiting
stream is registered in a list <opening_list> stored in qcc with <start>
as timestamp in qcs for the stream opening. Once a qcs is attached to a
sedesc, it is removed from <opening_list>. When refreshing MUX timeout,
if <opening_list> is not empty, the first waiting stream is used to set
MUX timeout.
This is efficient as streams are stored in the list in their creation
order so CPU usage is minimal. Also, the size of the list is
automatically restricted by flow control limitation so it should not
grow too much.
Streams are insert in <opening_list> by application protocol layer. This
is because only application protocol can differentiate streams for HTTP
messaging from internal usage. A function qcs_wait_http_req() has been
added to register a request stream by app layer. QUIC MUX can then
remove it from the list in qc_attach_sc().
As a side-note, it was necessary to implement attach qcc_app_ops
callback on hq-interop module to be able to insert a stream in waiting
list. Without this, a BUG_ON statement would be triggered when trying to
remove the stream on sedesc attach. This is to ensure that every
requests streams are registered for http-request timeout.
MUX timeout is explicitely refreshed on MAX_STREAM_DATA and STOP_SENDING
frame parsing to schedule http-request timeout if a new stream has been
instantiated. It was already done on STREAM parsing due to a previous
patch.
Timeout in QUIC MUX has evolved from the simple first implementation. At
the beginning, a connection was considered dead unless bidirectional
streams were opened. This was abstracted through an app callback
is_active().
Now this paradigm has been reversed and a connection is considered alive
by default, unless an error has been reported or a timeout has already
been fired. The callback is_active() is thus not used anymore and can be
safely removed to simplify qcc_is_dead().
This commit should be backported to 2.6.
Clean the API used by decode_qcs() and transcoder internal functions.
Parsing functions now returns a ssize_t which represents the number of
consumed bytes or a negative error code. The total consumed bytes is
returned via decode_qcs().
The API is now unified and cleaner. The MUX can thus simply use the
return value of decode_qcs() instead of substracting the data bytes in
the buffer before and after the call. Transcoders functions are not
anymore obliged to remove consumed bytes from the buffer which was not
obvious.
Slightly modify decode_qcs function used by transcoders. The MUX now
gives a buffer instance on which each transcoder is free to work on it.
At the return of the function, the MUX removes consume data from its own
buffer.
This reduces the number of invocation to qcs_consume at the end of a
full demuxing process. The API is also cleaner with the transcoders not
responsible of calling it with the risk of having the input buffer
freed if empty.
As a mirror to qcc/qcs types, add a h3c pointer into h3s struct. This
should help to clean up H3 code and avoid to use qcs.qcc.ctx to retrieve
the h3c instance.
Function arguments and local variables called "cs" were renamed to "sc"
to avoid future confusion. The "nb_cs" stream-connector counter was
renamed to "nb_sc" and qc_attach_cs() was renamed to qc_attach_sc().
The function doesn't return a pointer to the mux but to the mux stream
(h1s, h2s etc). Let's adjust its name to reflect this. It's rarely used,
the name can be enlarged a bit. And of course s/cs/sc to accommodate for
the updated name.
This renames the "struct conn_stream" to "struct stconn" and updates
the descriptions in all comments (and the rare help descriptions) to
"stream connector" or "connector". This touches a lot of files but
the change is minimal. The local variables were not even renamed, so
there's still a lot of "cs" everywhere.
Send MAX_STREAM_DATA frames when at least half of the allocated
flow-control has been demuxed, frame and cleared. This is necessary to
support QUIC STREAM with received data greater than a buffer.
Transcoders must use the new function qcc_consume_qcs() to empty the QCS
buffer. This will allow to monitor current flow-control level and
generate a MAX_STREAM_DATA frame if required. This frame will be emitted
via qc_io_cb().
Add a ncbuf for data reception on qcs. Thanks to this, the MUX is able
to buffered all received frame directly into the buffer. Flow control
parameters will be used to ensure there is never an overflow.
This change will simplify Rx path with the future deletion of acked
frames tree previously used for frames out of order.
Group the endpoint target of a conn-stream, its context and the associated
flags in a dedicated structure in the conn-stream. It is not inlined in the
conn-stream structure. There is a dedicated pool.
For now, there is no complexity. It is just an indirection to get the
endpoint or its context. But the purpose of this structure is to be able to
share a refcounted context between the mux and the conn-stream. This way, it
will be possible to preserve it when the mux is detached from the
conn-stream.
This change is only significant for the multiplexer part. For the applets,
the context and the endpoint are the same. Thus, there is no much change. For
the multiplexer part, the connection was used to set the conn-stream
endpoint and the mux's stream was the context. But it is a bit strange
because once a mux is installed, it takes over the connection. In a
wonderful world, the connection should be totally hidden behind the mux. The
stream-interface and, in a lesser extent, the stream, still access the
connection because that was inherited from the pre-multiplexer era.
Now, the conn-stream endpoint is the mux's stream (an opaque entity for the
conn-stream) and the connection is the context. Dedicated functions have
been added to attached an applet or a mux to a conn-stream.
Add a new app layer operation is_active. This can be used by the MUX to
check if the connection can be considered as active or not. This is used
inside qcc_is_dead as a first check.
For example on HTTP/3, if there is at least one bidir client stream
opened the connection is active. This explicitly ignore the uni streams
used for control and qpack as they can never be closed during the
connection lifetime.
Thanks to all previous changes, it is now possible to move the
stream-interface into the conn-stream. To do so, some SI functions are
removed and their conn-stream counterparts are added. In addition, the
conn-stream is now responsible to create and release the
stream-interface. While the stream-interfaces were inlined in the stream
structure, there is now a pointer in the conn-stream. stream-interfaces are
now dynamically allocated. Thus a dedicated pool is added. It is a temporary
change because, at the end, the stream-interface structure will most
probably disappear.
