Some config parsing functions need to return composite status codes
when they rely on other functions. Let's provide a few such codes
for general use and extend them later.
Some freq counters will have to work on periods different from 1 second.
The original freq counters rely on the period to be exactly one second.
The new ones (freq_ctr_period) let the user define the period in ticks,
and all computations are operated over that period. When reading a value,
it indicates the amount of events over that period too.
We'll need to divide 64 bits by 32 bits with new frequency counters.
Gcc does not know when it can safely do that, but the way we build
our operations let us be sure. So let's provide an optimised version
for that purpose.
This member will be used later when frontends are created on the
fly by some tasks. It will also be usable later if we need to
support multiple config instances for example.
When a connection is closed on a stream interface, some iohandlers
will need to be informed in order to release some resources. This
normally happens upon a shutr+shutw. It is the equivalent of the
fd_delete() call which is done for real sockets, except that this
time we release internal resources.
It can also be used with real sockets because it does not cost
anything else and might one day be useful.
The quote_arg() function can be used to quote an argument or indicate
"end of line" if it's null or empty. It should be useful to more precisely
report location of problems in the configuration.
When an entry already exists, we just need to update its expiration
timer. Let's have a dedicated function for that instead of spreading
open code everywhere.
This change also ensures that an update of an existing sticky session
really leads to an update of its expiration timer, which was apparently
not the case till now. This point needs to be checked in 1.4.
Till now sticky sessions only held server IDs. Now there are other
data types so it is not acceptable anymore to overwrite the server ID
when writing something. The server ID must then only be written from
the caller when appropriate. Doing this has also led to separate
lookup and storage.
This one can be parsed on the "stick-table" after with the "store"
keyword. It will hold the number of connections matching the entry,
for use with ACLs or anything else.
The stick_tables will now be able to store extra data for a same key.
A limited set of extra data types will be defined and for each of them
an offset in the sticky session will be assigned at startup time. All
of this information will be stored in the stick table.
The extra data types will have to be specified after the new "store"
keyword of the "stick-table" directive, which will reserve some space
for them.
pattern.c depended on stick_table while in fact it should be the opposite.
So we move from pattern.c everything related to stick_tables and invert the
dependency. That way the code becomes more logical and intuitive.
The name 'exps' and 'keys' in struct stksess was confusing because it was
the same name as in the table which holds all of them, while they only hold
one node each. Remove the trailing 's' to more clearly identify who's who.
Right now we're only able to store a server ID in a sticky session.
The goal is to be able to store anything whose size is known at startup
time. For this, we store the extra data before the stksess pointer,
using a negative offset. It will then be easy to cumulate multiple
data provided they each have their own offset.
It's very disturbing to see the "denied req" counter increase without
any other session counter moving. In fact, we can't count a rejected
TCP connection as "denied req" as we have not yet instanciated any
session at all. Let's use a new counter for that.
Now we're able to reject connections very early, so we need to use a
different counter for the connections that are received and the ones
that are accepted and converted into sessions, so that the rate limits
can still apply to the accepted ones. The session rate must still be
used to compute the rate limit, so that we can reject undesired traffic
without affecting the rate.
Analysers don't care (and must not care) about a few flags such as
BF_AUTO_CLOSE or BF_AUTO_CONNECT, so those flags should not be listed
in the BF_MASK_STATIC bitmask.
We should also recheck if some buffer flags should be ignored or not
in process_session() when deciding if we must loop again or not.
A new function session_accept() is now called from the lower layer to
instanciate a new session. Once the session is instanciated, the upper
layer's frontent_accept() is called. This one can be service-dependant.
That way, we have a 3-phase accept() sequence :
1) protocol-specific, session-less accept(), which is pointed to by
the listener. It defaults to the generic stream_sock_accept().
2) session_accept() which relies on a frontend but not necessarily
for use in a proxy (eg: stats or any future service).
3) frontend_accept() which performs the accept for the service
offerred by the frontend. It defaults to frontend_accept() which
is really what is used by a proxy.
The TCP/HTTP proxies have been moved to this mode so that we can now rely on
frontend_accept() for any type of session initialization relying on a frontend.
The next step will be to convert the stats to use the same system for the stats.
The conn_retries still lies in the session and its initialization depends
on the backend when it may not yet be known. Let's first move it to the
stream interface.
It's not normal to initialize the server-side stream interface from the
accept() function, because it may change later. Thus, we introduce a new
stream_sock_prepare_interface() function which is called just before the
connect() and which sets all of the stream_interface's callbacks to the
default ones used for real sockets. The ->connect function is also set
at the same instant so that we can easily add new server-side protocols
soon.
The connection timeout stored in the buffer has not been used since the
stream interface were introduced. Let's get rid of it as it's one of the
things that complicate factoring of the accept() functions.
We can disable the monitor-net rules on a listener if this flag is not
set in the listener's options. This will be useful when we don't want
to check that fe->addr is set or not for non-TCP frontends.
The new LI_O_TCP_RULES listener option indicates that some TCP rules
must be checked upon accept on this listener. It is now checked by
the frontend and the L4 rules are evaluated only in this case. The
flag is only set when at least one tcp-req rule is present in the
frontend.
The L4 rules check function has now been moved to proto_tcp.c where
it ought to be.
For a long time we had two large accept() functions, one for TCP
sockets instanciating proxies, and another one for UNIX sockets
instanciating the stats interface.
A lot of code was duplicated and both did not work exactly the same way.
Now we have a stream_sock layer accept() called for either TCP or UNIX
sockets, and this function calls the frontend-specific accept() function
which does the rest of the frontend-specific initialisation.
Some code is still duplicated (session & task allocation, stream interface
initialization), and might benefit from having an intermediate session-level
accept() callback to perform such initializations. Still there are some
minor differences that need to be addressed first. For instance, the monitor
nets should only be checked for proxies and not for other connection templates.
Last, we renamed l->private as l->frontend. The "private" pointer in
the listener is only used to store a frontend, so let's rename it to
eliminate this ambiguity. When we later support detached listeners
(eg: FTP), we'll add another field to avoid the confusion.
The 'client.c' file now only contained frontend-specific functions,
so it has naturally be renamed 'frontend.c'. Same for client.h. This
has also been an opportunity to remove some cross references from
files that should not have depended on it.
In the end, this file should contain a protocol-agnostic accept()
code, which would initialize a session, task, etc... based on an
accept() from a lower layer. Right now there are still references
to TCP.
Some functions which act on generic buffer contents without being
tcp-specific were historically in proto_tcp.c. This concerns ACLs
and RDP cookies. Those have been moved away to more appropriate
locations. Ideally we should create some new files for each layer6
protocol parser. Let's do that later.
Just like we do on health checks, we should consider that ACLs that make
use of buffer data are layer 6 and not layer 4, because we'll soon have
to distinguish between pure layer 4 ACLs (without any buffer) and these
ones.
This ACL was missing in complex setups where the status of a remote site
has to be considered in switching decisions. Until there, using a server's
status in an ACL required to have a dedicated backend, which is a bit heavy
when multiple servers have to be monitored.
The code is now ready to support loading pattern from filesinto trees. For
that, it will be required that the ACL keyword has a flag ACL_MAY_LOOKUP
and that the expr is case sensitive. When that is true, the pattern will
have a flag ACL_PAT_F_TREE_OK to indicate that it is possible to feed the
tree instead of a usual pattern if the parsing function is able to do this.
The tree's root is pre-initialized in the pattern's value so that the
function can easily find it. At that point, if the parsing function decides
to use the tree, it just sets ACL_PAT_F_TREE in the return flags so that
the caller knows the tree has been used and the pattern can be recycled.
That way it will be possible to load some patterns into the tree when it
is compatible, and other ones as linear linked lists. A good example of
this might be IPv4 network entries : right now we support holes in masks,
but this very rare feature is not compatible with binary lookup in trees.
So the parser will be able to decide itself whether the pattern can go to
the tree or not.
If we want to be able to match ACLs against a lot of possible values, we
need to put those values in trees. That will only work for exact matches,
which is normally just what is needed.
Right now, only IPv4 and string matching are planned, but others might come
later.
This is used to disable persistence depending on some conditions (for
example using an ACL matching static files or a specific User-Agent).
You can see it as a complement to "force-persist".
In the configuration file, the force-persist/ignore-persist declaration
order define the rules priority.
Used with the "appsesion" keyword, it can also help reducing memory usage,
as the session won't be hashed the persistence is ignored.
Some servers do not completely conform with RFC2616 requirements for
keep-alive when they receive a request with "Connection: close". More
specifically, they don't bother using chunked encoding, so the client
never knows whether the response is complete or not. One immediately
visible effect is that haproxy cannot maintain client connections alive.
The second issue is that truncated responses may be cached on clients
in case of network error or timeout.
scar Fras Barranco reported this issue on Tomcat 6.0.20, and
Patrik Nilsson with Jetty 6.1.21.
Cyril Bont proposed this smart idea of pretending we run keep-alive
with the server and closing it at the last moment as is already done
with option forceclose. The advantage is that we only change one
emitted header but not the overall behaviour.
Since some servers such as nginx are able to close the connection
very quickly and save network packets when they're aware of the
close negociation in advance, we don't enable this behaviour by
default.
"option http-pretend-keepalive" will have to be used for that, in
conjunction with "option http-server-close".
Using get_ip_from_hdr2() we can look for occurrence #X or #-X and
extract the IP it contains. This is typically designed for use with
the X-Forwarded-For header.
Using "usesrc hdr_ip(name,occ)", it becomes possible to use the IP address
found in <name>, and possibly specify occurrence number <occ>, as the
source to connect to a server. This is possible both in a server and in
a backend's source statement. This is typically used to use the source
IP previously set by a upstream proxy.
The transparent proxy address selection was set in the TCP connect function
which is not the most appropriate place since this function has limited
access to the amount of parameters which could produce a source address.
Instead, now we determine the source address in backend.c:connect_server(),
right after calling assign_server_address() and we assign this address in
the session and pass it to the TCP connect function. This cannot be performed
in assign_server_address() itself because in some cases (transparent mode,
dispatch mode or http_proxy mode), we assign the address somewhere else.
This change will open the ability to bind to addresses extracted from many
other criteria (eg: from a header).
We'll need another flag in the 'options' member close to PR_O_TPXY_*,
and all are used, so let's move this easy one to options2 (which are
already used for SQL checks).
The following patch fixed an issue but brought another one :
296897 [MEDIUM] connect to servers even when the input has already been closed
The new issue is that when a connection is inspected and aborted using
TCP inspect rules, now it is sent to the server before being closed. So
that test is not satisfying. A probably better way is not to prevent a
connection from establishing if only BF_SHUTW_NOW is set but BF_SHUTW
is not. That way, the BF_SHUTW flag is not set if the request has any
data pending, which still fixes the stats issue, but does not let any
empty connection pass through.
Also, as a safety measure, we extend buffer_abort() to automatically
disable the BF_AUTO_CONNECT flag. While it appears to always be OK,
it is by pure luck, so better safe than sorry.
We are seeing both real servers repeatedly going on- and off-line with
a period of tens of seconds. Packet tracing, stracing, and adding
debug code to HAProxy itself has revealed that the real servers are
always responding correctly, but HAProxy is sometimes receiving only
part of the response.
It appears that the real servers are sending the test page as three
separate packets. HAProxy receives the contents of one, two, or three
packets, apparently randomly. Naturally, the health check only
succeeds when all three packets' data are seen by HAProxy. If HAProxy
and the real servers are modified to use a plain HTML page for the
health check, the response is in the form of a single packet and the
checks do not fail.
(...)
I've added buffer and length variables to struct server, and allocated
space with the rest of the server initialisation.
(...)
It seems to be working fine in my tests, and handles check responses
that are bigger than the buffer.
today I've noticed that the stats page still displays v1.3 in the
"Updates" link, due to the PRODUCT_BRANCH value in version.h, then
it's maybe time to send you the result (notice that the patch updates
PRODUCT_BRANCH to "1.4").
--
Cyril Bont
When trying to spot some complex bugs, it's often needed to access
information on stuck sessions, which is quite difficult. This new
command helps one get detailed information about a session, with
flags, timers, states, etc... The buffer data are not dumped yet.
Often we need to understand why some transfers were aborted or what
constitutes server response errors. With those two counters, it is
now possible to detect an unexpected transfer abort during a data
phase (eg: too short HTTP response), and to know what part of the
server response errors may in fact be assigned to aborted transfers.
The bounce realign function was algorithmically good but as expected
it was not cache-friendly. Using it with large requests caused so many
cache thrashing that the function itself could drain 70% of the total
CPU time for only 0.5% of the calls !
Revert back to a standard memcpy() using a specially allocated swap
buffer. We're now back to 2M req/s on pipelined requests.
It is wrong to merge FE and BE stats for a proxy because when we consult a
BE's stats, it reflects the FE's stats eventhough the BE has received no
traffic. The most common example happens with listen instances, where the
backend gets credited for all the trafic even when a use_backend rule makes
use of another backend.
The trash buffer may now be smaller than a buffer because we can tune
it at run time. This causes a risk when we're trying to use it as a
temporary buffer to realign unaligned requests, because we may have to
put up to a full buffer into it.
Instead of doing a double copy, we're now relying on an open-coded
bouncing copy algorithm. The principle is that we move one byte at
a time to its final place, and if that place also holds a byte, then
we move it too, and so on. We finish when we've moved all the buffer.
It limits the number of memory accesses, but since it proceeds one
byte at a time and with random walk, it's not cache friendly and
should be slower than a double copy. However, it's only used in
extreme situations and the difference will not be noticeable.
It has been extensively tested and works reliably.
This is a first attempt to add a maintenance mode on servers, using
the stat socket (in admin level).
It can be done with the following command :
- disable server <backend>/<server>
- enable server <backend>/<server>
In this mode, no more checks will be performed on the server and it
will be marked as a special DOWN state (MAINT).
If some servers were tracking it, they'll go DOWN until the server
leaves the maintenance mode. The stats page and the CSV export also
display this special state.
This can be used to disable the server in haproxy before doing some
operations on this server itself. This is a good complement to the
"http-check disable-on-404" keyword and works in TCP mode.
Support the new syntax (http-request allow/deny/auth) in
http stats.
Now it is possible to use the same syntax is the same like in
the frontend/backend http-request access control:
acl src_nagios src 192.168.66.66
acl stats_auth_ok http_auth(L1)
stats http-request allow if src_nagios
stats http-request allow if stats_auth_ok
stats http-request auth realm LB
The old syntax is still supported, but now it is emulated
via private acls and an aditional userlist.
Add generic authentication & authorization support.
Groups are implemented as bitmaps so the count is limited to
sizeof(int)*8 == 32.
Encrypted passwords are supported with libcrypt and crypt(3), so it is
possible to use any method supported by your system. For example modern
Linux/glibc instalations support MD5/SHA-256/SHA-512 and of course classic,
DES-based encryption.
Implement Base64 decoding with a reverse table.
The function accepts and decodes classic base64 strings, which
can be composed from many streams as long each one is properly
padded, for example: SGVsbG8=IEhBUHJveHk=IQ==
Just as for the req* rules, we can now condition rsp* rules with ACLs.
ACLs match on response, so volatile request information cannot be used.
A warning is emitted if a configuration contains such an anomaly.
From now on, if request filters have ACLs defined, these ACLs will be
evaluated to condition the filter. This will be used to conditionally
remove/rewrite headers based on ACLs.
This function automatically builds a rule, considering the if/unless
statements, and automatically updates the proxy's acl_requires, the
condition's file and line.
Now a server can check the contents of the header X-Haproxy-Server-State
to know how haproxy sees it. The same values as those reported in the stats
are provided :
- up/down status + check counts
- throttle
- weight vs backend weight
- active sessions vs backend sessions
- queue length
- haproxy node name
Currently we cannot easily add headers nor anything to HTTP checks
because the requests are pre-formatted with the last CRLF. Make the
check code add the CRLF itself so that we can later add useful info.
Some converters will need one or several arguments. It's not possible
to write a simple generic parser for that, so let's add the ability
for each converter to support its own argument parser, and call it
to get the arguments when it's specified. If unspecified, the arguments
are passed unmodified as string+len.
The pattern type converters currently support a string arg and a length.
Sometimes we'll prefer to pass them a list or a structure. So let's convert
the string and length into a generic void* and int that each converter may
use as it likes.
Despite what is explicitly stated in HTTP specifications,
browsers still use the undocumented Proxy-Connection header
instead of the Connection header when they connect through
a proxy. As such, proxies generally implement support for
this stupid header name, breaking the standards and making
it harder to support keep-alive between clients and proxies.
Thus, we add a new "option http-use-proxy-header" to tell
haproxy that if it sees requests which look like proxy
requests, it should use the Proxy-Connection header instead
of the Connection header.
This is used to force access to down servers for some requests. This
is useful when validating that a change on a server correctly works
before enabling the server again.
Sometimes we need to be able to change the default kernel socket
buffer size (recv and send). Four new global settings have been
added for this :
- tune.rcvbuf.client
- tune.rcvbuf.server
- tune.sndbuf.client
- tune.sndbuf.server
Those can be used to reduce kernel memory footprint with large numbers
of concurrent connections, and to reduce risks of write timeouts with
very slow clients due to excessive kernel buffering.
We need to improve Connection header handling in the request for it
to support the upcoming keep-alive mode. Now we have two flags which
keep in the session the information about the presence of a
Connection: close and a Connection: keep-alive headers in the initial
request, as well as two others which keep the current state of those
headers so that we don't have to parse them again. Knowing the initial
value is essential to know when the client asked for keep-alive while
we're forcing a close (eg in server-close mode). Also the Connection
request parser is now able to automatically remove single header values
at the same time they are parsed. This provides greater flexibility and
reliability.
All combinations of listen/front/back in all modes and with both
1.0 and 1.1 have been tested.
Some header values might be delimited with spaces, so it's not enough to
compare "close" or "keep-alive" with strncasecmp(). Use word_match() for
that.
Calling this function after http_find_header2() automatically deletes
the current value of the header, and removes the header itself if the
value is the only one. The context is automatically adjusted for a
next call to http_find_header2() to return the next header. No other
change nor test should be made on the transient context though.
While waiting in a keep-alive state for a request, we want to silently
close if we don't get anything. However if we get a partial request it's
different because that means the client has started to send something.
This requires a new transaction flag. It will be used to implement a
distinct timeout for keep-alive and requests.
This change, suggested by Cyril Bont, makes a lot of sense and
would have made it obvious that sessid was not properly initialized
while switching to keep-alive. The code is now cleaner.
The stream_int_cond_close() function was added to preserve the
contents of the response buffer because stream_int_retnclose()
was buggy. It flushed the response instead of flushing the
request. This caused issues with pipelined redirects followed
by error messages which ate the previous response.
This might even have caused object truncation on pipelined
requests followed by an error or by a server redirection.
Now that this is fixed, simply get rid of the now useless
function.
Sometimes it can be desired to return a location which is the same
as the request with a slash appended when there was not one in the
request. A typical use of this is for sending a 301 so that people
don't reference links without the trailing slash. The name of the
new option is "append-slash" and it can be used on "redirect"
statements in prefix mode.
Some message pointers were not usable once the message reached the
HTTP_MSG_DONE state. This is the case for ->som which points to the
body because it is needed to parse chunks. There is one case where
we need the beginning of the message : server redirect. We have to
call http_get_path() after the request has been parsed. So we rely
on ->sol without counting on ->som. In order to achieve this, we're
making ->rq.{u,v} relative to the beginning of the message instead
of the buffer. That simplifies the code and makes it cleaner.
Preliminary tests show this is OK.
Several HTTP analysers used to set those flags to values that
were useful but without considering the possibility that they
were not called again to clean what they did. First, replace
direct flag manipulation with more explicit macros. Second,
enforce a rule stating that any buffer which changes one of
these flags from the default must restore it after completion,
so that other analysers see correct flags.
With both this fix and the previous one about analyser bits,
we should not see any more stuck sessions.
This patch implements default-server support allowing to change
default server options. It can be used in [defaults] or [backend]/[listen]
sections. Currently the following options are supported:
- error-limit
- fall
- inter
- fastinter
- downinter
- maxconn
- maxqueue
- minconn
- on-error
- port
- rise
- slowstart
- weight
Supported informations, available via "tr/td title":
- cap: capabilities (proxy)
- mode: one of tcp, http or health (proxy)
- id: SNMP ID (proxy, socket, server)
- IP (socket, server)
- cookie (backend, server)
