CS_FL_ISBACK is a new flag, set on backend conn-streams. We must just be
careful to preserve this flag when the endpoint is detached from the
conn-stream.
All old flags CS_FL_* are now moved in the endpoint scope and renamed
CS_EP_* accordingly. It is a systematic replacement. There is no true change
except for the health-check and the endpoint reset. Here it is a bit special
because the same conn-stream is reused. Thus, we must handle endpoint
allocation errors. To do so, cs_reset_endp() has been adapted.
Thanks to this last change, it will now be possible to simplify the
multiplexer and probably the applets too. A review must also be performed to
remove some flags in the channel or the stream-interface. The HTX will
probably be simplified too. Finally, there is now some place in the
conn-stream to move info from the stream-interface.
The conn-stream endpoint is now shared between the conn-stream and the
applet or the multiplexer. If the mux or the applet is created first, it is
responsible to also create the endpoint and share it with the conn-stream.
If the conn-stream is created first, it is the opposite.
When the endpoint is only owned by an applet or a mux, it is called an
orphan endpoint (there is no conn-stream). When it is only owned by a
conn-stream, it is called a detached endpoint (there is no mux/applet).
The last entity that owns an endpoint is responsible to release it. When a
mux or an applet is detached from a conn-stream, the conn-stream
relinquishes the endpoint to recreate a new one. This way, the endpoint
state is never lost for the mux or the applet.
It is a transient commit to prepare next changes. Now, when a conn-stream is
created from an applet or a multiplexer, an endpoint is always provided. In
addition, the API to create a conn-stream was specialized to have one
function per type.
The next step will be to share the endpoint structure.
It is a transient commit to prepare next changes. It is possible to pass a
pre-allocated endpoint to create a new conn-stream. If it is NULL, a new
endpoint is created, otherwise the existing one is used. There no more
change at the conn-stream level.
In the applets, all conn-stream are created with no pre-allocated
endpoint. But for multiplexers, an endpoint is systematically created before
creating the conn-stream.
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.
The function cs_init() is only called by cs_new(). The conn-stream
initialization will be reviewed. It is easier to do it in cs_new() instead
of using a dedicated function. cs_new() is pretty simple, there is no reason
to split the code in this case.
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.
This patch is mandatory to invert the endpoint and the context in the
conn-stream. There is no common type (at least for now) for the entity
representing a mux (h1s, h2s...), thus we must set its type when the
endpoint is attached to a conn-stream. There is 2 types for the conn-stream
endpoints: the mux (CS_FL_ENDP_MUX) and the applet (CS_FL_ENDP_APP).
Since the CS/SI refactoring, the .release callback function may be called
twice. The first call when a shutdown for read or for write is performed.
The second one when the applet is detached from its conn-stream. The second
call must be guarded, just like the first one, to only be performed is the
stream-interface is not the in disconnected (SI_ST_DIS) or closed
(SI_ST_CLO) state.
To simplify the fix, we now always rely on si_applet_release() function.
It is 2.6-specific, no backport is needed.
In the same way a stream has always valid conn-streams, when a health-checks
is created, a conn-stream is now created and the health-check is attached on
it, as an app. This simplify a bit the connect part when a health-check is
running.
cs_detach_app() function is added to detach an app from a conn-stream. And
now, both cs_detach_app() and cs_detach_endp() release the conn-stream when
both the app and the endpoint are detached.
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.
In the same way the conn-stream has a pointer to the stream endpoint , this
patch adds a pointer to the application entity in the conn-stream
structure. For now, it is a stream or a health-check. It is mandatory to
merge the stream-interface with the conn-stream.
