The remaining large functions are those allocating/initializing and
occasionally freeing connections, conn_streams and sockaddr. Let's
move them to connection.c. In fact, cs_free() is the only one-liner
but let's move it along with the other ones since a call will be
small compared to the rest of the work done there.
The following inlined functions are particularly large (and probably not
inlined at all by the compiler), and together represent roughly half of
the file, while they're used at most once per connection. They were moved
to connection.c.
conn_upgrade_mux_fe, conn_install_mux_fe, conn_install_mux_be,
conn_install_mux_chk, conn_delete_from_tree, conn_init, conn_new,
conn_free
We do not really need to have them inlined, and having xxhash.h included
by connection.h results in this 4700-lines file being processed 101 times
over the whole project, which accounts for 13.5% of the total size!
Additionally, half of the functions are only needed from connection.c.
Let's move the functions there and get rid of the painful include.
The build time is now down to 6.2s just due to this.
The hash type stored everywhere is XXH64_hash_t, which annoyingly forces
everyone to include the huge xxhash file. We know it's an uint64_t because
that's its purpose and the type is only made to abstract it on machines
where uint64_t is not availble. Let's switch the type to uint64_t
everywhere and avoid including xxhash from the type file.
This one doesn't use anything from an SSL context, it only checks the
type of the transport layer of a connection, thus it belongs to
connection.h. This is particularly visible due to all the ifdefs
around it in various call places.
We'll need to improve the API to pass other arguments in the future, so
let's start to adapt better to the current use cases. task_new() is used:
- 18 times as task_new(tid_bit)
- 18 times as task_new(MAX_THREADS_MASK)
- 2 times with a single bit (in a loop)
- 1 in the debug code that uses a mask
This patch provides 3 new functions to achieve this:
- task_new_here() to create a task on the calling thread
- task_new_anywhere() to create a task to be run anywhere
- task_new_on() to create a task to run on a specific thread
The change is trivial and will allow us to later concentrate the
required adaptations to these 3 functions only. It's still possible
to call task_new() if needed but a comment was added to encourage the
use of the new ones instead. The debug code was not changed and still
uses it.
Move the code to allocate/free the mux cleanup task outside of the polling
loop. A new thread_alloc/free handler is registered for this in
connection.c.
This has the benefit to clean up the polling loop code. And as another
benefit, if the task allocation fails, the handler can report an error
to exit the haproxy process. This prevents a potential null pointer
dereferencing.
This should fix the github issue #1389.
This must be backported up to 2.4.
The bc_conn_err and bc_conn_err_str sample fetches give the status of
the connection on the backend side. The error codes and error messages
are the same than the ones that can be raised by the fc_conn_err fetch.
The fc_conn_err and fc_conn_err_str sample fetches give information
about the problem that made the connection fail. This information would
previously only have been given by the error log messages meaning that
thanks to these fetches, the error log can now be included in a custom
log format. The log strings were all found in the conn_err_code_str
function.
This function appends to a buffer some information from a connection.
This will be used by traces and possibly some debugging as well. A
frontend/backend/server, transport/control layers, source/destination
ip:port, connection pointer and direction are reported depending on
the available information.
No idea why this was put inlined into connection.h, it's used only once
for haproxy -vv, and requires tools.h, causing an undesired dependency
from connection.h. Let's move it to connection.c instead where it ought
to have been.
Implement a safe mechanism to close front idling connection which
prevents the soft-stop to complete. Every h1/h2 front connection is
added in a new per-thread list instance. On shutdown, a new task is
waking up which calls wake mux operation on every connection still
present in the new list.
A new stopping_list attach point has been added in the connection
structure. As this member is only used for frontend connections, it
shared the same union as the session_list reserved for backend
connections.
bc_http_major sample fetch now works when it is called from a
tcp-check. When it happens, the session origin is a check. The backend
connection is retrieved from the conn-stream attached to the check.
If required, this path may easily be backported as far as 2.2.
fc_http_major and bc_http_major sample fetches return the major digit of the
HTTP version used, respectively, by the frontend and the backend
connections, based on the mux. However, in reality, "2" is returned if the
H2 mux is detected, otherwise "1" is inconditionally returned, regardless
the mux used. Thus, if called for a raw TCP connection, "1" is returned.
To fix this bug, we now get the multiplexer flags, if there is one, to be
sure MX_FL_HTX is set.
I guess it was made this way on purpose when the H2 multiplexer was
introduced in the 1.8 and with the legacy HTTP mode there is no other
solution at the connection level. Thus this patch should be backported as
far as 2.2. For the 2.0, it must be evaluated first because of the legacy
HTTP mode.
The default proxy was passed as a variable to all parsers instead of a
const, which is not without risk, especially when some timeout parsers used
to make some int pointers point to the default values for comparisons. We
want to be certain that none of these parsers will modify the defaults
sections by accident, so it's important to mark this proxy as const.
This patch touches all occurrences found (89).
There are multiple per-thread lists in the listeners, which isn't the
most efficient in terms of cache, and doesn't easily allow to store all
the per-thread stuff.
Now we introduce an srv_per_thread structure which the servers will have an
array of, and place the idle/safe/avail conns tree heads into. Overall this
was a fairly mechanical change, and the array is now always initialized for
all servers since we'll put more stuff there. It's worth noting that the Lua
code still has to deal with its own deinit by itself despite being in a
global list, because its server is not dynamically allocated.
If dispatch mode or transparent backend is used, the backend connection
target is a proxy instead of a server. In these cases, the reuse of
backend connections is not consistent.
With the default behavior, no reuse is done and every new request uses a
new connection. However, if http-reuse is set to never, the connection
are stored by the mux in the session and can be reused for future
requests in the same session.
As no server is used for these connections, no reuse can be made outside
of the session, similarly to http-reuse never mode. A different
http-reuse config value should not have an impact. To achieve this, mark
these connections as private to have a defined behavior.
For this feature to properly work, the connection hash has been slightly
adjusted. The server pointer as an input as been replaced by a generic
target pointer to refer to the server or proxy instance. The hash is
always calculated on connect_server even if the connection target is not
a server. This also requires to allocate the connection hash node for
every backend connections, not just the one with a server target.
Remove ebmb_node entry from struct connection and create a dedicated
struct conn_hash_node. struct connection contains now only a pointer to
a conn_hash_node, allocated only for connections where target is of type
OBJ_TYPE_SERVER. This will reduce memory footprints for every
connections that does not need http-reuse such as frontend connections.
Use the proxy protocol frame if proxy protocol is activated on the
server line. Do not add anymore these connections in the private list.
If some requests are made with the same proxy fields, they can reuse
the idle connection.
The reg-tests proxy_protocol_send_unique_id must be adapted has it
relied on the side effect behavior that every requests from a same
connection reused a private server connection. Now, a new connection is
created as expected if the proxy protocol fields differ.
The source address is used as an input to the the server connection hash. The
address and port are used as separate hash inputs. Do not add anymore these
connections in the private list.
This parameter is set only if used in the transparent-proxy mode.
The destination address is used as an input to the server connection hash. The
address and port are used as separated hash inputs. Note that they are not used
when statically specified on the server line. This is only useful for dynamic
destination address.
This is typically used when the server address is dynamically set via the
set-dst action. The address and port are separated hash parameters.
Most notably, it should fixed set-dst use case (cf github issue #947).
The sni parameter is an input to the server connection hash. Do not add
anymore connections with dynamic sni in the private list. Thus, it is
now possible to reuse a server connection if they use the same sni.
The pointer of the target server is used as a first parameter for the
server connection hash calcul. This prevents the hash to be null when no
specific parameters are present, and can serve as a simple defense
against an attacker trying to reuse a non-conform connection.
This is a preliminary work for the calcul of the backend connection
hash. A structure conn_hash_params is the input for the operation,
containing the various specific parameters of a connection.
The high bits of the hash will reflect the parameters present as input.
A set of macros is written to manipulate the connection hash and extract
the parameters/payload.
The server idle/safe/available connection lists are replaced with ebmb-
trees. This is used to store backend connections, with the new field
connection hash as the key. The hash is a 8-bytes size field, used to
reflect specific connection parameters.
This is a preliminary work to be able to reuse connection with SNI,
explicit src/dst address or PROXY protocol.
This changes the subscribe/unsubscribe functions to rely on the control
layer's check_events/ignore_events. At the moment only the socket version
of these functions is present so the code should basically be the same.
Now we don't touch the fd anymore there, instead we rely on the ->drain()
provided by the control layer. As such the function was renamed to
conn_ctrl_drain().
conn_fd_handler() is 100% specific to socket code. It's about time
it moves to sock.c which manipulates socket FDs. With it comes
conn_fd_check() which tests for the socket's readiness. The ugly
connection status check at the end of the iocb was moved to an inlined
function in connection.h so that if we need it for other socket layers
it's not too hard to reuse.
The code was really only moved and not changed at all.
The send() loop present in this function and the error handling is already
present in raw_sock_from_buf(). Let's rely on it instead and stop touching
the FD from this place. The send flag was changed to use a more agnostic
CO_SFL_*. The name was changed to "conn_ctrl_send()" to remind that it's
meant to be used to send at the lowest level.
This last call to conn_cond_update_polling() is now totally misleading as
the function only stops polling in case of unrecoverable connection error.
Let's open-code the test to make it more prominent and explain what we're
trying to do there. It's even almost certain this code is never executed
anymore, as the only remaining case should be a mux's wake function setting
CO_FL_ERROR without disabling the polling, but they need to be audited first
to make sure this is the case.
conn_stop_polling() in fact only calls fd_stop_both() after checking
that the ctrl layer is ready. It's the case in conn_fd_check() so
let's get rid of this next-to-last user of this function.
At a few places we used to rely on conn->owner to retrieve the session
while the session is already known. This is not correct because at some
of these points the reason the connection's owner was still the session
(instead of NULL) is a mistake. At one place a comparison is even made
between the session and conn->owner assuming it's valid without checking
if it's NULL. Let's clean this up to use the session all the time.
Note that this will be needed for a forthcoming fix and will have to be
backported.
Roughly half of the calls to sockadr_alloc() are made to copy an already
known address. Let's optionally pass it in argument so that the function
can handle the copy at the same time, this slightly simplifies its usage.
No protocol defines it anymore. The last user used to be the monitor-net
stuff that got partially broken already when the tcp_drain() function
moved to conn_sock_drain() with commit e215bba95 ("MINOR: connection:
make conn_sock_drain() work for all socket families") in 1.9-dev2.
A part of this will surely move back later when non-socket connections
arrive with QUIC but better keep the API clean and implement what's
needed in time instead.
When a connection is marked as private, it is now added in the session server
list. We don't wait a stream is detached from the mux to do so. When the
connection is created, this happens after the mux creation. Otherwise, it is
performed when the connection is marked as private.
To allow that, when a connection is created, the session is systematically set
as the connectin owner. Thus, a backend connection has always a owner during its
creation. And a private connection has always a owner until its death.
Note that outside the detach() callback, if the call to session_add_conn()
failed, the error is ignored. In this situation, we retry to add the connection
into the session server list in the detach() callback. If this fails at this
step, the multiplexer is destroyed and the connection is closed.
When the multiplexer creation is delayed after the handshakes phase, the
connection is added in the available connection list if http-reuse never is not
configured for the backend. But it is a wrong statement. At this step, the
connection is not safe because it is a new connection. So it must be added in
the available connection list only if http-reuse always is used.
No backport needed, this is 2.2-dev.
When a connection is created and the multiplexer is installed, if the connection
is marked as private, don't consider it as available, regardless the number of
available streams. This test is performed when the mux is installed when the
connection is created, in connect_server(), and when the mux is installed after
the handshakes stage.
No backport needed, this is 2.2-dev.
We used to have 3 thread-based arrays for toremove_lock, idle_cleanup,
and toremove_connections. The problem is that these items are small,
and that this creates false sharing between threads since it's possible
to pack up to 8-16 of these values into a single cache line. This can
cause real damage where there is contention on the lock.
This patch creates a new array of struct "idle_conns" that is aligned
on a cache line and which contains all three members above. This way
each thread has access to its variables without hindering the other
ones. Just doing this increased the HTTP/1 request rate by 5% on a
16-thread machine.
The definition was moved to connection.{c,h} since it appeared a more
natural evolution of the ongoing changes given that there was already
one of them declared in connection.h previously.
This effectively reverts the two following commits:
6f95f6e11 ("OPTIM: connection: disable receiving on disabled events when the run queue is too high")
065a02561 ("MEDIUM: connection: don't stop receiving events in the FD handler")
The problem as reported in issue #662 is that when the events signals
the readiness of input data that has to be forwarded over a congested
stream, the mux will read data and wake the stream up to forward them,
but the buffer full condition makes this impossible immediately, then
nobody in the chain will be able to disable the event after it was
first reported. And given we don't know at the connection level whether
an event was already reported or not, we can't decide anymore to
forcefully stop it if for any reason its processing gets delayed.
The problem is magnified in issue #662 by the fact that a shutdown is
reported with pending data occupying the buffer. The shutdown will
strike in loops and cause the upper layer stream to be notified until
it's handled, but with a buffer full it's not possible to call cs_recv()
hence to purge the event.
All this can only be handled optimally by implementing a lower layer,
direct mux-to-mux forwarding that will not require any scheduling. This
was no wake up will be needed and the event will be instantly handled
or paused for a long time.
For now let's simply revert these optimizations. Running a 1 MB transfer
test over H2 using 8 connections having each 32 streams with a limited
link of 320 Mbps shows the following profile before this fix:
calls syscall (100% CPU)
------ -------
259878 epoll_wait
519759 clock_gettime
17277 sendto
17129 recvfrom
672 epoll_ctl
And the following one after the fix:
calls syscall (2-3% CPU)
------ -------
17201 sendto
17357 recvfrom
2304 epoll_wait
4609 clock_gettime
1200 epoll_ctl
Thus the behavior is much better.
No backport is needed as these patches were only in 2.2-dev.
Many thanks to William Dauchy for reporting a lot of details around this
difficult issue.
This patch fixes all the leftovers from the include cleanup campaign. There
were not that many (~400 entries in ~150 files) but it was definitely worth
doing it as it revealed a few duplicates.
Most of the files dealing with error reports have to include log.h in order
to access ha_alert(), ha_warning() etc. But while these functions don't
depend on anything, log.h depends on a lot of stuff because it deals with
log-formats and samples. As a result it's impossible not to embark long
dependencies when using ha_warning() or qfprintf().
This patch moves these low-level functions to errors.h, which already
defines the error codes used at the same places. About half of the users
of log.h could be adjusted, sometimes revealing other issues such as
missing tools.h. Interestingly the total preprocessed size shrunk by
4%.
There's no point splitting the file in two since only cfgparse uses the
types defined there. A few call places were updated and cleaned up. All
of them were in C files which register keywords.
There is nothing left in common/ now so this directory must not be used
anymore.
