The analysis of cs_rx_endp_more() showed that the purpose is for a stream
endpoint to inform the connector that it's ready to deliver more data to
that one, and conversely cs_rx_endp_done() that it's done delivering data
so it should not be bothered again for this.
This was modified two ways:
- the operation is no longer performed on the connector but on the
endpoint so that there is no more doubt when reading applet code
about what this rx refers to; it's the endpoint that has more or
no more data.
- an applet implementation is also provided and mostly used from
applet code since it saves the caller from having to access the
endpoint descriptor.
It's visible that the flag ought to be inverted because some places
have to set it by default for no reason.
These functions are used by the application layer to disable or enable
reading at the stream connector's level when the input buffer failed to
be allocated (or was finally allocated). The new names makes things
clearer.
This makes SE_FL_APPLET_NEED_CONN autonomous, in that we check for it
everywhere we have a relevant cs_rx_blocked(), so that the flag doesn't
need anymore to be covered by cs_rx_blocked(). Indeed, this flag doesn't
really translate a receive blocking condition but rather a refusal to
wake up an applet that is waiting for a connection to finish to setup.
This also ensures we will not risk to set it back on a new endpoint
after cs_reset_endp() via SE_FL_APP_MASK, because the flag being
specific to the endpoint only and not to the connector, we don't
want to preserve it when replacing the endpoint.
It's possible that cs_chk_rcv() could later be further simplified if
we can demonstrate that the two tests in it can be merged.
One flag (RXBLK_SHUT) is always set with CF_SHUTR, so in order to remove
it, we first need to make sure we always check for CF_SHUTR where
cs_rx_blocked() is being used.
sc_is_send_allowed() is now used everywhere instead of the combination
of cs_tx_endp_ready() && !cs_tx_blocked(). There's no place where we
need them individually thus it's simpler. The test was placed in cs_util
as we'll complete it later.
The following functions which act on a connection-based stream connector
were renamed to sc_conn_* (~60 places):
cs_conn_drain_and_shut
cs_conn_process
cs_conn_read0
cs_conn_ready
cs_conn_recv
cs_conn_send
cs_conn_shut
cs_conn_shutr
cs_conn_shutw
These functions return the app-layer associated with an stconn, which
is a check, a stream or a stream's task. They're used a lot to access
channels, flags and for waking up tasks. Let's just name them
appropriately for the stream connector.
We're starting to propagate the stream connector's new name through the
API. Most call places of these functions that retrieve the channel or its
buffer are in applets. The local variable names are not changed in order
to keep the changes small and reviewable. There were ~92 uses of cs_ic(),
~96 of cs_oc() (due to co_get*() being less factorizable than ci_put*),
and ~5 accesses to the buffer itself.
This applies the change so that the applet code stops using ci_putchk()
and friends everywhere possible, for the much saferapplet_put*() instead.
The change is mechanical but large. Two or three functions used to have no
appctx and a cs derived from the appctx instead, which was a reminiscence
of old times' stream_interface. These were simply changed to directly take
the appctx. No sensitive change was performed, and the old (more complex)
API is still usable when needed (e.g. the channel is already known).
The change touched roughly a hundred of locations, with no less than 124
lines removed.
It's worth noting that the stats applet, the oldest of the series, could
get a serious lifting, as it's still very channel-centric instead of
propagating the appctx along the chain. Given that this code doesn't
change often, there's no emergency to clean it up but it would look
better.
This also follows the natural naming. There are roughly 238 changes, all
totally trivial. conn_stream-t.h has become completely void of any
"conn_stream" related stuff now (except its 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.
Just like for the appctx, this is a pointer to a stream endpoint descriptor,
so let's make this explicit and not confuse it with the full endpoint. There
are very few changes thanks to the preliminary refactoring of the flags
manipulation.
That's the "stream endpoint" pointer. Let's change it now while it's
not much spread. The function __cs_endp_target() wasn't yet renamed
because that will change more globally soon.
This changes all main uses of cs->endp->flags to the sc_ep_*() equivalent
by applying coccinelle script cs_endp_flags.cocci.
Note: 143 locations were touched, manually reviewed and found to be OK,
except a single one that was adjusted in cs_reset_endp() where the flags
are read and filtered to be used as-is and not as a boolean, hence was
replaced with sc_ep_get() & $FLAGS.
The script was applied with all includes:
spatch --in-place --recursive-includes -I include --sp-file $script $files
Even if `unique_id` and `s->unique_id` are identical it is a bit odd to
`isttest()` `unique_id` and then use `s->unique_id` in the call to `http_add_header()`.
This "issue" was introduced in a17e66289c08a5bfadc1bb5b5f2c618c9299fe1b,
because before that commit the function returned the length of the ID, as it
was not an ist.
It is just a helper function that call the .init applet callback function,
if it exists. This will simplify a bit the init stage when a new applet is
started. For now, this callback function is only used when a new service is
started.
The session created for frontend applets is now totally owns by the
corresponding appctx. It means the appctx is now responsible to release
it. This removes the hack in stream_free() about frontend applets to be sure
to release the session.
This one is the pointer to the conn_stream which is always in the
endpoint that is always present in the appctx, thus it's not needed.
This patch removes it and replaces it with appctx_cs() instead. A
few occurences that were using __cs_strm(appctx->owner) were moved
directly to appctx_strm() which does the equivalent.
This one has been misused for a while as well, it's time to deprecate it
since we don't use it anymore. It will be removed in 2.7 and for now is
only marked as deprecated. Since we need to guarantee that it's zeroed
before starting any applet or CLI command, it was moved into an anonymous
union where its sibling is not marked as deprecated so that we can
continue to initialize it without triggering a warning.
If you found this commit after a bisect session you initiated to figure
why you got some build warnings and don't know what to do, have a look
at the code that deals with the "show fd", "show sess" or "show servers"
commands, as it's supposed to be self-explanatory about the tiny changes
to apply to your code to port it. If you find APPLET_MAX_SVCCTX to be
too small for your use case, either kindly ask for a tiny extension
(and try to get your code merged), or just use a pool.
The state was a constant, let's remove what remains of the switch/case.
The code from the "case" statement was only reindented as can be checked
with "git show -b".
This state is only an alias for "thr >= global.nbthread" which is the
sole condition that indicates the end and reaches it. Let's just drop
this state. There's only the STATE_LIST that's left.
This state was only used to preset the list element. Now that we can
guarantee that the context can be properly preset during the parsing
we don't need this state anymore. The first pointer has to be set to
point to the first stream during the initial call which is detected
by the pointer not yet being set (null). Thanks to this we can also
remove one state check on the abort path.
This makes use of the generic command context allocation so that the
appctx doesn't have to declare a specific one anymore. The context is
created during parsing.
There were plenty of leftovers from old code that were never removed
and that are not needed at all since these files do not use any
definition depending on fcntl.h, let's drop them.
A conn-stream is never detached from an endpoint or an application alone,
except on a reset. Thus, to avoid any error, these functions are now
private. And cs_destroy() function is added to destroy a conn-stream. This
function is called when a stream is released, on the front and back
conn-streams, and when a health-check is finished.
When a client abort is detected with the server conn-stream in CS_ST_INI
state, there is no reason to detach the endpoing because we know there is no
endpoint attached to this conn-stream. This patch depends on the commit
"BUG/MEDIUM: conn-stream: Set back CS to RDY state when the appctx is
created".
Since the recent changes about the conn-streams, the stream dump in "show
sess all" command is a bit mangled. front and back conn-stream are now
properly displayed (csf and csb). In addition, when there is no backend
endpoint, "APPCTX" was always reported. Now, "NONE" is reported in this
case.
It is 2.6-specific. No backport needed.
Github issue #472 reports a problem with short client connections making
stick-table entries disappear. The problem is in fact totally different
and stems at the connection establishment step.
What happens is that the stick-table there has a single entry. The
"stick-on" directive is forced to purge an existing entry before being
able to create a new one. The new entry will be committed during the
call to process_store_rules() on the response path.
But if the client sends the FIN immediately after the connection is set
up (e.g. using nc -z) then the SHUTR is received and will cancel the
connection setup just after it starts. This cancellation will induce a
call to cs_shutw() which will in turn leave the server-side state in
ST_DIS. This transition from ST_CON to ST_DIS doesn't belong to the
list of handled transition during the connection setup so it will be
handled right after on the regular path, causing the connection to be
closed. Because of this, we never pass through back_establish() and
the backend's analysers are never set on the response channel, which
is why process_store_rules() is not called and the stick-tables entry
never committed.
The comment above the code that causes this transition clearly says
that the function is to be used after the connection is established
with the server, but there's no such protection, and we always have
the AUTO_CLOSE flag there (but there's hardly any available condition
to eliminate it).
This patch adds a test for the connection not being in ST_CON or for
option abortonclose being set. It's sufficient to do the job and it
should not cause issues.
One concern was that the transition could happen during cs_recv()
after the connection switches from CON to RDY then the read0 would
be taken into account and would cause DIS to appear, which is not
handled either. But that cannot happen because cs_recv() doesn't do
anything until it's in ST_EST state, hence the read0() cannot be
called from CON/RDY. Thus the transition from CON to DIS is only
possible in back_handle_st_con() and back_handle_st_rdy() both of
which are called when dealing with the transition already, or when
abortonclose is set and the client aborts before connect() succeeds.
It's possible that some further improvements could be made to detect
this specific transition but it doesn't seem like anything would have
to be added.
This issue was first reported on 2.1. The abortonclose area is very
sensitive so it would be wise to backport slowly, and probably no
further than 2.4.
process_stream() and all associated functions now manipulate conn-streams.
stream-interfaces are no longer used. In addition, function to dump info
about a stream no longer print info about stream-interfaces.
Remaining flags and associated functions are move in the conn-stream
scope. These flags are added on the endpoint and not the conn-stream
itself. This way it will be possible to get them from the mux or the
applet. The functions to get or set these flags are renamed accordingly with
the "cs_" prefix and updated to manipualte a conn-stream instead of a
stream-interface.
si_update_both() is renamed stream_update_both_cs() and moved in stream.c.
The function is slightly changed to manipulate the stream instead the front
and back conn-streams.
si_update_rx(), si_update_tx() and si_update() are renamed cs_update_rx(),
cs_upate_tx() and cs_update() and updated to manipulate a conn-stream
instead of a stream-interface.
si_register_applet() and si_applet_release() are renamed
cs_register_applet() and cs_applet_release() and now manipulate a
conn-stream instead of a stream-inteface.
si_shutr(), si_shutw(), si_chk_rcv() and si_chk_snd() are moved in the
conn-stream scope and renamed, respectively, cs_shutr(), cs_shutw(),
cs_chk_rcv(), cs_chk_snd() and manipulate a conn-stream instead of a
stream-interface.
wait_event structure is moved in the conn-stream. The tasklet is only
created if the conn-stream is attached to a mux and released when the mux is
detached. This implies a subtle change. In stream_int_chk_rcv() function,
the wakeup of the tasklet was removed because there is no longer tasklet at
this stage (stream_int_chk_rcv() is a callback function of si_embedded_ops).
si_retnclose() is used to send a reply to a client before closing. There is
no use on the server side, in spite of the function is generic. Thus, it is
renamed stream_retnclose() and moved into the stream scope. The function now
handle a stream and explicitly send a message to the client.
The stream-interface state (SI_ST_*) is now in the conn-stream. It is a
mechanical replacement for now. Nothing special. SI_ST_* and SI_SB_* were
renamed accordingly. Utils functions to manipulate these infos were moved
under the conn-stream scope.
But it could be good to keep in mind that this part should be
reworked. Indeed, at the CS level, we only need to know if it is ready to
receive or to send. The state of conn-stream from INI to EST is only used on
the server side. The client CS is immediately set to EST. Thus current
SI_ST_* states should probably be moved to the stream to reflect the server
connection state during the establishment stage.
