This one enforces a per-process connection rate limit, regardless of what
may be set per frontend. It can be a way to limit the CPU usage of a process
being severely attacked.
The side effect is that the global process connection rate is now measured
for each incoming connection, so it will be possible to report it.
This option permits to change the global maxconn setting within the
limit that was set by the initial value, which is now reported as the
hard maxconn value. This allows to immediately accept more concurrent
connections or to stop accepting new ones until the value passes below
the indicated setting.
The main use of this option is on systems where many haproxy instances
are loaded and admins need to re-adjust resource sharing at run time
to regain a bit of fairness between processes.
The way the unix socket is initialized is awkward. Some of the settings are put
in the sockets itself, other ones in the backend. And more importantly the
global.maxsock value is adjusted so that the stats socket evades the global
maxconn value. This complexifies maxsock computations for nothing, since the
stats socket is not supposed to receive hundreds of concurrent connections when
the global maxconn is very low. What is needed however is to ensure that there
are always connections left for the stats socket even when traffic sockets are
saturated, but this guarantee is not offered anymore by current code.
So as of now, the stats socket is subject to the global maxconn limitation just
as any other socket until a reservation mechanism is implemented.
Some syslog servers escape quotes, which make the resulting logs unusable
for URL processing since the parser looks for the first field beginning
with a quote. It now supports also fields starting with backslash and
quote in order to address this. No performance impact was measured.
The code was merged with the error code checking which is very similar and
which shares the same information. The new test adds about 1% slowdown to
error checking but makes it more reliable when facing wrongly formated
status codes.
Sometimes a bad content-length header is encountered and this causes
an abort. It's hard to debug without a trace, so let's take a capture
of the contents when this happens.
If a server starts to respond but stops before the body, then we
capture the truncated response. We don't do this on the request
because it would happen too often upon stupid attacks.
Trailing spaces after headers were not trimmed, only the leading ones
were. An issue was detected today with a content-length value which
was padded with spaces and which was rejected. Recent updates to the
http-bis draft made it a lot more clear that such spaces must be ignored,
so this is what this patch does.
It should be backported to 1.4.
Many inet_ntop calls were partially right, which was hard to detect given
the complex combinations. Some of them were relying on the listener's proto
instead of the address itself, which could have been different when dealing
with an accept-proxy connection.
The new addr_to_str() function does the dirty job and returns the family, which
makes it particularly suited to calls from switch/case statements. A large number
of if/else statements were removed and the stats output could even be cleaned up
in the case of session dump.
As a side effect of doing this, the resulting code is smaller by almost 1kB.
All changed parts have been tested and provided expected output.
A similar issue as the previous one causes port mapping to fail in some
combinations of client and server address families. Using the macros fixes
the issue.
In the number of switch/case statements added for IPv6 changes,
one was wrong and caused the check port to be ignored for outgoing
connection because the socket's family was not taken at the right
place. Use the set_host_port() macro instead to fix the issue.
The same cleanup could be performed at a number of other places
and should follow shortly.
Special thanks to Stephane Bakhos of Techboom for reporting a
detailed analysis of this bug.
Patch d5b9fd95 was missing an initialisation of "ctx.table.target", which caused
"show table" to segfault if it was issued after a "show errors" (target pointer == -1).
Some older libc don't define splice() and and don't define _syscall*()
either, which causes build errors if splicing is enabled.
To solve this, we now split the syscall redefinition into two layers :
- one file per syscall (epoll, splice)
- one common file to declare the _syscall*() macros
The code is cleaner because files using the syscalls just have to include
their respective file. It's not adviced to merge multiple syscall families
into a same file if all are not intended to be used simultaneously, because
defining unused static functions causes warnings to be emitted during build.
As a result, the new USE_MY_SPLICE parameter was added in order to be able
to define the splice() syscall separately.
If "option forwardfor" has the "if-none" argument, then the header is
only added when the request did not already have one. This option has
security implications, and should not be set blindly.
Manoj Kumar reported a case where haproxy would crash upon start-up. The
cause was an "http-check expect" statement declared in the defaults section,
which caused a NULL regex to be used during the check. This statement is not
allowed in defaults sections precisely because this requires saving a copy
of the regex in the default proxy. But the check was not made to prevent it
from being declared there, hence the issue.
Instead of adding code to detect its abnormal use, we decided to implement
it. It was not that much complex because the expect_str part was not used
with regexes, so it could hold the string form of the regex in order to
compile it again for every backend (there's no way to clone regexes).
This patch has been tested and works. So it's both a bugfix and a minor
feature enhancement.
It should be backported to 1.4 though it's not critical since the config
was not supposed to be supported.
"[MINOR] session: add a pointer to the new target into the session" (664beb8)
introduced a regression by changing the type of a peer's target from
TARG_TYPE_PROXY to TARG_TYPE_NONE. The effect of this is that during
a soft-restart the new process no longer tries to connect to the
old process to replicate its stick tables.
This patch sets the type of a peer's target as TARG_TYPE_PROXY and
replication on soft-restart works once again.
It is now possible to filter by termination code with -tcn <termcode>, to be
able to track one kind of errors, for example after counting it with -tc.
Use -TCN <termcode> gives you the opposite.
Adding health checks has become a real pain, with cross-references to all
checks everywhere because they're all a single bit. Since they're all
exclusive, let's change this to have a check number only. We reserve 4
bits allowing up to 16 checks (15+tcp), only 7 of which are currently
used. The code has shrunk by almost 1kB and we saved a few option bits.
The "dispatch" option has been moved to px->options, making a few tests
a bit cleaner.
This patch provides a new "option redis-check" statement to enable server health checks based on redis PING request (http://www.redis.io/commands/ping).
The new "set maxconn frontend XXX" statement on the stats socket allows
the admin to change a frontend's maxconn value. If some connections are
queued, they will immediately be accepted up to the new limit. If the
limit is lowered, new connections acceptation might be delayed. This can
be used to temporarily reduce or increase the impact of a specific frontend's
traffic on the whole process.
This global task is used to periodically check for end of resource shortage
and to try to enable queued listeners again. This is important in case some
temporary system-wide shortage is encountered, so that we don't have to wait
for an existing connection to be released before checking the queue again.
For situations where listeners are queued due to the global maxconn being
reached, the task is woken up at least every second. For situations where
a system resource shortage is detected (memory, sockets, ...) the task is
woken up at least every 100 ms. That way, recovery from severe events can
still be achieved under acceptable conditions.
This was revealed with one of the very latest patches which caused
the listener_queue not to be initialized on the stats socket frontend.
And in fact a number of other ones were missing too. This is getting so
boring that now we'll always make use of the same function to initialize
any proxy. Doing so has even saved about 500 bytes on the binary due to
the avoided code redundancy.
No backport is needed.
This function is finally not needed anymore, as it has been replaced with
a per-proxy task that is scheduled when some limits are encountered on
incoming connections or when the process is stopping. The savings should
be noticeable on configs with a large number of proxies. The most important
point is that the rate limiting is now enforced in a clean and solid way.
Peers were stopped on every call to maintain_proxies when stopping=1,
while they should only be stopped once upon call to soft_stop(). This
bug has little impact, mostly increased CPU usage. It's not needed to
backport it.
Instead of waking a listener up then making it sleep, we only wake them up
if we know their rate limit is fine. In the future we could improve on top
of that by deciding to wake a proxy-specific task in XX milliseconds to
take care of enabling the listeners again.
Patch d9bbe17b used to limit the rate-limit to off-by-one to avoid
a busy loop when the limit is reached. Now that the listeners are
automatically disabled and queued when a limit is reached, we don't
need this workaround anymore and can bring back the most accurate
computation.
Those states have been replaced with PR_STFULL and PR_STREADY respectively,
as it is what matches them the best now. Also, two occurrences of PR_STIDLE
in peers.c have been removed as this did not provide any form of error recovery
anyway.
Now maintain_proxies() only changes proxies states and does not affect their
listeners anymore since they are autonomous. A proxy will switch between the
PR_STIDLE and PR_STRUN states depending whether it's saturated or not. Next
step will consist in renaming PR_STIDLE to PR_STFULL. This state is now only
used to report the proxy state in the stats.
