Because channel_is_empty() function does now only check the channel's
buffer, we can remove it and rely on co_data() instead. Of course, all tests
must be inverted.
channel_is_empty() is thus removed.
It is important to split channels and I/O buffers. When data are pushed in
an I/O buffer, we consider them as forwarded. The channel never sees
them. Fast-forwarded data are now handled in the SE only.
Now the kernel splicing support was removed, we can add mux-to-mux
fast-forward support. Of course, the splicing support will be reintroduced
in the muxes themselves but this will be transparent.
Changes are mainly located into sc_conn_recv() and sc_conn_send().
mux-to-mux fast-forwarding will be added. To avoid mix with the splicing and
simplify the commits, the kernel splicing support is removed from the
stconn. CF_KERN_SPLICING flag is removed and the support is no longer tested
in process_stream().
In the stconn part, rcv_pipe() callback function is no longer called.
Reg-tests scripts testing the kernel splicing are temporarly marked as
broken.
It is unused for now, but the iobuf structure now owns a pointer to a
buffer. This buffer will be used to perform mux-to-mux fast-forwarding when
splicing is not supported or unusable. This pointer should be filled by an
endpoint to let the opposite one forward data.
Extra fields, in addition to the buffer, are mandatory because the buffer
may already contains some data. the ".offset" field may be used may be used
as the position to start to copy data. Finally, the amount of data copied in
this buffer must be saved in ".data" field.
Some flags are also added to prepare next changes. And helper stconn
fnuctions are updated to also count data in the buffer. For a first
implementation, it is not planned to handle data in the buffer and in the
pipe in same time. But it will be possible to do so.
Instead of talking about kernel splicing at stconn/sedesc level, we now try
to talk about mux-to-mux fast-forwarding. To do so, 2 functions were added
to know if there are fast-forwarded data and to retrieve this amount of
data. Of course, for now, there is only data in a pipe.
In addition, some flags were renamed to reflect this notion. Note the
channel's documentation was not updated yet.
The pipes used to put data when the kernel splicing is in used are moved in
the SE descriptors. For now, it is just a simple remplacement but there is a
major difference with the pipes in the channel. The data are pushed in the
consumer's pipe while it was pushed in the producer's pipe. So it means the
request data are now pushed in the pipe of the backend SE descriptor and
response data are pushed in the pipe of the frontend SE descriptor.
The idea is to hide the pipe from the channel/SC side and to be able to
handle fast-forwading in pipe but also in buffer. To do so, the pipe is
inside a new entity, called iobuf. This entity will be extended.
When read/write timeouts were refactored in 2.8, we decided to change when a
send activity had to be reported. Before, everytime some data were sent a
send activity were reported. At this time, the channel's wex timer were
updated. During the refactoring, we decided to limit send activity to sends
that ampty te channel's buffer, consuming all outgoing data. Idea behind
this change was to protect haproxy against clients consumming data very
slowly.
However, it is too strict. Some congested muxes but still active can hit the
client or the server timeout. It seems a bit unfair. It is especially
visible with QUIC/H3 but it is probably also possible with H2 if the window
size is small.
The better is to restore the old behavior.
This patch must be backported to 2.8.
It is a revert of following patches:
* d7111e7ac ("MEDIUM: stconn: Don't requeue the stream's task after I/O")
* 3479d99d5 ("BUG/MEDIUM: stconn: Update stream expiration date on blocked sends")
Because the first one is reverted, the second one is useless and can be reverted
too.
The issue here is that I/O may be performed without stream wakeup. So if no
expiration date was set on the last call to process_stream(), the stream is
never rescheduled and no timeout can be detected. This especially happens on
TCP streams because fast-forward is enabled very early.
Instead of tracking all places where the stream's expiration data must be
updated, it is now centralized in sc_notify(), as it was performed before
the timeout refactoring.
This patch must be backported to 2.8.
The commit 7f59d68fe2 ("BUG/MEDIIM: stconn: Flush output data before
forwarding close to write side") introduced a regression. When a write
timeout is detected, the shutdown is no longer forwarded. Dependig on the
channels state, it may block the processing, waiting the client or the
server leaves.
The commit above tries to avoid to truncate messages on shutdown but on
write timeout, if the channel is not empty, there is nothing more we can do
to send these data. It means the endpoint is unable to send data. In this
case, we must forward the shutdown.
This patch should be backported as far as 2.2.
It only concerns the front SC. But it is important to report a read activity
when a stream is created and attached to the front SC, especially in TCP. In
HTTP, when this happens, the request was necessarily received. But in TCP,
the client may open a connection without sending anything. We must still
report a first read activity in this case to be able to properly report
client timeout.
This patch must be backported to 2.8.
In the SC function responsible to perform shutdown, there is a statement
inhibiting the shutdown if an error was encountered on the SC. This
statement is inherited from very old version and should in fact be
removed. The error may be set from the stream. In this case the shutdown
must be performed. In all cases, it is not a big deal if the shutdown is
performed twice because underlying functions already handle multiple calls.
This patch does not fix any bug. Thus there is no reason to backport it.
An applet is not woken up on sending path if it is not waiting for data or
if it states it will not consume data. However, it is important to still
wake it up if there is a pending shutdown. Otherwise, the event may be
missed and some data may remain blocked in the channel's buffer.
Because of this bug, it is possible to have a stream stuck if data are also
blocked on the opposite channel. It is for instance possible to hit the buf
with the stats applet and a client not consuming data.
This patch must slowly be backported as far as 2.2. It should partially fix
issue #2249.
The server timeout must not be handled during the connection establishment
to not superseed the connect timeout. To do so, we must not consider
outgoing data are blocked during this stage. Concretly, it means the fsb
time must not be updated during connection establishment.
It is not an issue with regular clients because the server timeout is only
defined when the connection is estalished. However, it may be an issue for the
HTTP client, when the server timeout is lower than the connect timeout. In this
case, an early 502 may be reported with no connection retries.
This patch must be backported to 2.8.
When outgoing data are blocked, we must update the stream expiration date
and requeue the task. It is important to be sure to properly handle write
timeout, expecially if the stream cannot expire on reads. This bug was
introduced when handling of channel's timeouts was refactored to be managed
by the stream-connectors.
It is an issue if there is no server timeout and the client does not consume
the response (or the opposite but it is less common). It is also possible to
trigger the same scenario with applets on server side because, most of time,
there is no server timeout.
This patch must be backported to 2.8.
During the refactoring on SC/SE flags, it was stated that SE_FL_EOS flag
should not be set without on of SE_FL_EOI or SE_FL_ERROR flags. In fact, it
is a problem for the QUIC/H3 multiplexer. When a RST_STREAM frame is
received, it means no more data will be received from the peer. And this
happens before the end of the message (RST_STREAM frame received after the
end of the message are ignored). At this stage, it is a problem to report an
error because from the QUIC point of view, it is valid. Data may still be
sent to the peer. If an error is reported, this will stop the data sending
too.
In the same idea, the H1 mulitplexer reports an error when the message is
truncated because of a read0. But only an EOS flag should be reported in
this case, not an error. Fundamentally, it is important to distinguish
errors from shuts for reads because some cases are valid. For instance a H1
client can choose to stop uploading data if it received the server response.
So, relax tests on SE flags by removing BUG_ON_HOT() on SE_FL_EOS flag. For
now, the abort will be handled in the HTTP analyzers.
When the SC is detached from the endpoint, the xref between the endpoints is
removed. At this stage, the sedesc cannot be undefined. So we can remove the
test on it.
This issue should fix the issue #2156. No backport needed.
A xref is added between the endpoint descriptors. It is created when the
server endpoint is attached to the SC and it is destroyed when an endpoint
is detached.
This xref is not used for now. But it will be useful to retrieve info about
an endpoint for the opposite side. It is also the warranty there is still a
endpoint attached on the other side.
After a sending attempt, we check the opposite SC to see if it is waiting
for a minimum free space to receive more data. If the condition is
respected, it is unblocked. 0 is special case where the SC is
unconditionally unblocked.
During fast-forward, if the SC is waiting for a minimum free space to
receive more data and some data was sent, it is only unblock is the
condition is respected. 0 is special case where the SC is unconditionally
unblocked.
At the end of process_stream(), in sc_update_rx(), the SC is now unblocked
if it was waiting for room and the free space in the input buffer is large
enough. This patch should fix an issue with the compression filter that can
leave the channel's buffer empty while the endpoint is waiting for room to
progress. Indeed, in this case, because the buffer is empty, there is no
send attempt and no other way to unblock the SE.
This commit depends on following commits:
* MEDIUM: tree-wide: Change sc API to specify required free space to progress
* MINOR: stconn: Add a field to specify the room needed by the SC to progress
* MINOR: peers: Use the applet API to send message
* MINOR: stats: Use the applet API to write data
* MINOR: cli: Use applet API to write output message
It should fix a regression introduced with the commit 341a5783b
("BUG/MEDIUM: stconn: stop to enable/disable reads from streams via
si_update_rx").
It must be backported iff the commit above is also backported. It was not
backported yet and it is thus probably a good idea to not do so to avoid to
backport too many change..
sc_need_room() now takes the required free space to receive more data as
parameter. All calls to this function are updated accordingly. For now, this
value is set but not used. When we are waiting for a buffer, 0 is used. So
we expect to be unblocked ASAP. However this must be reviewed because
SC_FL_NEED_BUF is probably enough in this case and this flag is already set
if the input buffer allocation fails.
When the SC is blocked because it is waiting for room in the input buffer,
it will be responsible to specify the minimum free space required to
progress. In this commit, we only introduce the field in the stconn
structure that will be used to store this value. It is a signed value with
the following meaning:
* -1: The SC is waiting for room but not based on the buffer state. It
will be typically used during splicing when the pipe is full. In
this case, only a successful send can unblock the SC.
* >= 0; The minimum free space in the input buffer to unblock the SC. 0 is
a special value to specify the SC must be unblocked ASAP, by the
stream, at the end of process_stream() or when output data are
consumed on the opposite side.
On sending path, a pending error can be promoted to a terminal error at the
endpoint level (SE_FL_ERR_PENDING to SE_FL_ERROR). When this happens, we
must propagate the error on the SC to be able to handle it at the stream
level and eventually forward it to the other side.
Because of this bug, it is possible to freeze sessions, for instance on the
CLI.
It is a 2.8-specific issue. No backport needed.
In the same way than for a stream-connector attached to a mux, an EOS is now
propagated from an applet to its stream-connector. To do so, sc_applet_eos()
function is added.
Now there is a SC flag to state the endpoint has reported an end-of-stream,
it is possible to distinguish an EOS from an abort at the stream-connector
level.
sc_conn_read0() function is renamed to sc_conn_eos() and it propagates an
EOS by setting SC_FL_EOS instead of SC_FL_ABRT_DONE. It only concernes
stream-connectors attached to a mux.
SC_FL_EOS flag is added to report the end-of-stream at the SC level. It will
be used to distinguish end of stream reported by the endoint, via the
SE_FL_EOS flag, and the abort triggered by the stream, via the
SC_FL_ABRT_DONE flag.
In this patch, the flag is defined and is systematically tested everywhere
SC_FL_ABRT_DONE is tested. It should be safe because it is never set.
It is the last commit on this subject. we stop to use SE_FL_ERROR flag from
the SC, except at the I/O level. Otherwise, we rely on SC_FL_ERROR
flag. Now, there should be a real separation between SE flags and SC flags.
We can now fully rely on SC_FL_ERROR flag from the stream. The first step is
to stop to set the SE_FL_ERROR flag. Only endpoints are responsible to set
this flag. It was a design limitation. It is now fixed.
From the stream, when SE_FL_ERROR flag is tested, we now also test the
SC_FL_ERROR flag. Idea is to stop to rely on the SE descriptor to detect
errors.
The flag SC_FL_ERROR is added to ack errors on the endpoint. When
SE_FL_ERROR flag is detected on the SE descriptor, the corresponding is set
on the SC. Idea is to avoid, as far as possible, to manipulated the SE
descriptor in upper layers and know when an error in the endpoint is handled
by the SC.
For now, this flag is only set and cleared but never tested.
There is no reason to remove this flag. When the SC endpoint is reset, it is
replaced by a new one. The old one is released. It was useful when the new
endpoint inherited some flags from the old one. But it is no longer
performed. Thus there is no reason still unset this flag.
When an applet is woken up, before calling its io_handler, we pretend it has
no more data to deliver. So, after the io_handler execution, it is a bug if
an applet states it has more data to deliver while the end of input is
reached.
So a BUG_ON() is added to be sure it never happens.
It is not the SC responsibility to report errors on the SE descriptor. It is
the endpoint responsibility. It must switch SE_FL_ERR_PENDING into
SE_FL_ERROR if the end of stream was detected. It can even be considered as
a bug if it is not done by he endpoint.
So now, on sending path, a BUG_ON() is added to abort if SE_FL_EOS and
SE_FL_ERR_PENDING flags are set but not SE_FL_ERROR. It is trully important
to handle this case in the endpoint to be able to properly shut the endpoint
down.
Here again, it is just a flag renaming. In SC flags, there is no longer
shutdown for reads but aborts. For now this flag is set when a read0 is
detected. It is of couse not accurate. This will be changed later.
After the flag renaming, it is now the turn for the channel function to be
renamed and moved in the SC scope. channel_shutw_now() is replaced by
sc_schedule_shutdown(). The request channel is replaced by the front SC and
the response is replace by the back SC.
Because shutowns for reads are now considered as aborts, the shudowns for
writes can now be considered as shutdowns. Here it is just a flag
renaming. SC_FL_SHUTW_NOW is renamed SC_FL_SHUT_WANTED.
We erroneously though that an attempt to receive data was not possible if the SC
was waiting for more room in the channel buffer. A BUG_ON() was added to detect
bugs. And in fact, it is possible.
The regression was added in commit 341a5783b ("BUG/MEDIUM: stconn: stop to
enable/disable reads from streams via si_update_rx").
This patch should fix the issue #2115. It must be backported if the commit
above is backported.
SE_FL_EOS flag must never be set on the SE descriptor without SE_FL_EOI or
SE_FL_ERROR. When a mux or an applet report an end of stream, it must be
able to state if it is the end of input too or if it is an error.
Because all this part was recently refactored, especially the applet part,
it is a bit sensitive. Thus a BUG_ON_HOT() is used and not a BUG_ON().
The purpose of this patch is only a one-to-one replacement, as far as
possible.
CF_SHUTR(_NOW) and CF_SHUTW(_NOW) flags are now carried by the
stream-connecter. CF_ prefix is replaced by SC_FL_ one. Of course, it is not
so simple because at many places, we were testing if a channel was shut for
reads and writes in same time. To do the same, shut for reads must be tested
on one side on the SC and shut for writes on the other side on the opposite
SC. A special care was taken with process_stream(). flags of SCs must be
saved to be able to detect changes, just like for the channels.
Just like for end of input, the end of stream reported by the endpoint
(SE_FL_EOS flag) is now handled in sc_applet_process(). The idea is to have
applets acting as muxes by reporting events through the SE descriptor, as
far as possible.
The end of input reported by the endpoint (SE_FL_EOI flag), is now handled
in sc_applet_process(). This function is always called after an applet was
called. So, the applets can now only report EOI on the SE descriptor and
have no reason to update the channel too.
