This function will handle mux upgrades, for frontend connections only. It will
retrieve the best mux in the same way than conn_install_mux_fe except that the
mode and optionnally the proto are forced.
The new multiplexer is initialized using a new context and a specific input
buffer. Then, the old one is destroyed. If an error occurred, everything is
rolled back.
The mux's callback init() now take a pointer to a buffer as extra argument. It
must be used by the multiplexer as its input buffer. This buffer is always NULL
when a multiplexer is initialized with a fresh connection. But if a mux upgrade
is performed, it may be filled with existing data. Note that, for now, mux
upgrades are not supported. But this commit is mandatory to do so.
Since LIST_DEL_LOCKED() and LIST_POP_LOCKED() now automatically reinitialize
the removed element, there's no need for keeping this LIST_INIT() call in the
idle connection code.
Use the locked macros when manipulating idle_orphan_conns, so that other
threads can remove elements from it.
It will be useful later to avoid having a task per server and per thread to
cleanup the orphan list.
Add a per-thread counter of idling connections, and use it to determine
how many connections we should kill after the timeout, instead of using
the global counter, or we're likely to just kill most of the connections.
This should be backported to 1.9.
Use atomic operations when dealing with srv->curr_idle_conns, as it's shared
between threads, otherwise we could get inconsistencies.
This should be backported to 1.9.
When mux->init() fails, session_free() will call it again to unregister
it while it was already done, resulting in null derefs or use-after-free.
This typically happens on out-of-memory conditions during H1 or H2 connection
or stream allocation.
This fix must be backported to 1.9.
Instead of keeping track of the number of connections we're responsible for,
keep track of the number of connections we're responsible for that we are
currently considering idling (ie that we are not using, they may be in use
by other sessions), that way we can actually reuse connections when we have
more connections than the max configured.
When a session adds a connection to its connection list, we used to remove
connections for an another server if there were not enough room for our
server. This can't work, because those lists are now the list of connections
we're responsible for, not just the idle connections.
To fix this, allow for an unlimited number of servers, instead of using
an array, we're now using a linked list.
There was a reference to struct stream in conn_free() for the case
where we're freeing a connection that doesn't have a mux attached.
For now we know it's always a stream, and we only need to do it to
put a NULL in s->si[1].end.
Let's do it better by storing the pointer to si[1].end in the context
and specifying that this pointer is always nulled if the mux is null.
This way it allows a connection to detach itself from wherever it's
being used. Maybe we could even get rid of the condition on the mux.
We most often store the mux context there but it can also be something
else while setting up the connection. Better call it "ctx" and know
that it's the owner's context than misleadingly call it mux_ctx and
get caught doing suspicious tricks.
The SUB_CAN_SEND/SUB_CAN_RECV enum values have been confusing a few
times, especially when checking them on reading. After some discussion,
it appears that calling them SUB_RETRY_SEND/SUB_RETRY_RECV more
accurately reflects their purpose since these events may only appear
after a first attempt to perform the I/O operation has failed or was
not completed.
In addition the wait_reason field in struct wait_event which carries
them makes one think that a single reason may happen at once while
it is in fact a set of events. Since the struct is called wait_event
it makes sense that this field is called "events" to indicate it's the
list of events we're subscribed to.
Last, the values for SUB_RETRY_RECV/SEND were swapped so that value
1 corresponds to recv and 2 to send, as is done almost everywhere else
in the code an in the shutdown() call.
In session, don't keep an infinite number of connection that can idle.
Add a new frontend parameter, "max-session-srv-conns" to set a max number,
with a default value of 5.
Instead of trying to get the session from the connection, which is not
always there, and of course there could be multiple sessions per connection,
provide it with the init() and attach() methods, so that we know the
session for each outgoing stream.
Add a new command, "pool-max-conn" that sets the maximum number of connections
waiting in the orphan idling connections list (as activated with idle-timeout).
Using "-1" means unlimited. Using pools is now dependant on this.
There were a number of ugly setsockopt() calls spread all over
proto_http.c, proto_htx.c and hlua.c just to manipulate the front
connection's TOS, mark or TCP quick-ack. These ones entirely relied
on the connection, its existence, its control layer's presence, and
its addresses. Worse, inet_set_tos() was placed in proto_http.c,
exported and used from the two other ones, surrounded in #ifdefs.
This patch moves this code to connection.h and makes the other ones
rely on it without ifdefs.
We currently have conn_get_best_mux() to return the best mux for a
given protocol name, side and proxy mode. But we need the mux entry
as well in order to fix the bind_conf and servers at the end of the
config parsing. Let's split the function in two parts. It's worth
noting that the <conn> argument is never used anymore so this part
is eligible to some cleanup.
It looks like we forgot to report HTX when listing the muxes and their
respective protocols, leading to "NONE" being displayed. Let's report
"HTX" and "HTTP|HTX" since both will exist. Also fix a minor typo in
the output message.
Instead of just storing the last connection in the session, store all of
the connections, for at most MAX_SRV_LIST (currently 5) targets.
That way we can do keepalive on more than 1 outgoing connection when the
client uses HTTP/2.
This commit replaces the explicit pool creation that are made in
constructors with a pool registration. Not only this simplifies the
pools declaration (it can be done on a single line after the head is
declared), but it also removes references to pools from within
constructors. The only remaining create_pool() calls are those
performed in init functions after the config is parsed, so there
is no more user of potentially uninitialized pool now.
It has been the opportunity to remove no less than 12 constructors
and 6 init functions.
If an ALPN (or a NPN) was chosen for a server, defer choosing the mux until
after the SSL handshake is done, and the ALPN/NPN has been negociated, so
that we know which mux to pick.
Do not destroy the connection when we're about to destroy a stream. This
prevents us from doing keepalive on server connections when the client is
using HTTP/2, as a new stream is created for each request.
Instead, the session is now responsible for destroying connections.
When reusing connections, the attach() mux method is now used to create a new
conn_stream.
Introduce a new field in session, "srv_conn", and a linked list of sessions
in the connection. It will be used later when we'll switch connections
from being managed by the stream, to being managed by the session.
This method is used to retrieve the first known good conn_stream from
the mux. It will be used to find the other end of a connection when
dealing with the proxy protocol for example.
This option makes a proxy use only HTX-compatible muxes instead of the
HTTP-compatible ones for HTTP modes. It must be set on both ends, this
is checked at parsing time.
Avoid using conn_xprt_want_send/recv, and totally nuke cs_want_send/recv,
from the upper layers. The polling is now directly handled by the connection
layer, it is activated on subscribe(), and unactivated once we got the event
and we woke the related task.
Make sure we don't have any subscription when the connection is going in
idle mode, otherwise there's a race condition when the connection is
reused, if there are still old subscriptions, new ones won't be done.
No backport is needed.
When subscribing, we don't need to provide a list element, only the h2 mux
needs it. So instead, Add a list element to struct h2s, and use it when a
list is needed.
This forces us to use the unsubscribe method, since we can't just unsubscribe
by using LIST_DEL anymore.
This patch is larger than it should be because it includes some renaming.
As we don't know how subscriptions are handled, we can't just assume we can
use LIST_DEL() to unsubscribe, so introduce a new method to mux and connections
to do so.
Till now it was very difficult for a mux to know what proxy it was
working for. Let's pass the proxy when the mux is instanciated at
init() time. It's not yet used but the H1 mux will definitely need
it, just like the H2 mux when dealing with backend connections.
For struct connection, struct conn_stream, and for the h2 mux, add 2 new
lists, one that handles waiters for recv, and one that handles waiters for
recv and send. That way we can ask to subscribe for either recv or send.
This function returns the proxy associated to a connection. For front
connections it returns the frontend, and for back connections it
returns the backend. This will be used to retrieve some configuration
parameters from within a mux.
Sometimes a connection is prepared before the target is set, sometimes
after. There's no real rule since the few functions involved operate on
different and independent fields. Soon we'll benefit from knowing the
target at the connection layer, in order to figure the associated proxy
and retrieve the various parameters (timeouts etc). This patch slightly
reorders a few calls to conn_prepare() so that we can make sure that the
target is always known to the mux.
During a test it happened that a connection was deleted before the
stream it's attached to, resulting in a crash related to the fix
18a85fe ("BUG/MEDIUM: streams: Don't forget to remove the si from
the wait list.") during the LIST_DEL(). Make sure to always delete
the list's head in this case so that other elements can safely
detach later.
This is purely 1.9, no backport is needed.
Commit 7ce0c89 ("MEDIUM: mux: Use the mux protocol specified on
bind/server lines") assumed a bit too strongly that we could only have
servers on the connect side :-) It segfaults under this config :
defaults
contimeout 5s
clitimeout 5s
srvtimeout 5s
mode http
listen test1
bind :8001
dispatch 127.0.0.1:8002
frontend test2
mode http
bind :8002
redirect location /
No backport needed.
To do so, mux choices are split to handle incoming and outgoing connections in a
different way. The protocol specified on the bind/server line is used in
priority. Then, for frontend connections, the ALPN is retrieved and used to
choose the best mux. For backend connection, there is no ALPN. Finaly, if no
protocol is specified and no protocol matches the ALPN, we fall back on a
default mux, choosing in priority the first mux with exactly the same mode.
Because there can be several default multiplexers (without name), they are now
reported with the name "<default>". And a message warns they cannot be
referenced with the "proto" keyword on a bind line or a server line.
Multiplexers are not necessarily associated to an ALPN. ALPN is a TLS extension,
so it is not always defined or used. Instead, we now rather speak of
multiplexer's protocols. So in this patch, there are no significative changes,
some structures and functions are just renamed.
This function is generic and is able to automatically transfer data from a
buffer to the conn_stream's tx buffer. It does this automatically if the mux
doesn't define another snd_buf() function.
It cannot yet be used as-is with the conn_stream's txbuf without risking to
lose data on close since conn_streams need to be orphaned for this.
