For the random LB algorithm we need a random 32-bit hashing key that used
to be made of two calls to random(). Now we can simply perform a single
call to ha_random32() and get rid of the useless operations.
This is the replacement of failed attempt to add thread safety and
per-process sequences of random numbers initally tried with commit
1c306aa84d ("BUG/MEDIUM: random: implement per-thread and per-process
random sequences").
This new version takes a completely different approach and doesn't try
to work around the horrible OS-specific and non-portable random API
anymore. Instead it implements "xoroshiro128**", a reputedly high
quality random number generator, which is one of the many variants of
xorshift, which passes all quality tests and which is described here:
http://prng.di.unimi.it/
While not cryptographically secure, it is fast and features a 2^128-1
period. It supports fast jumps allowing to cut the period into smaller
non-overlapping sequences, which we use here to support up to 2^32
processes each having their own, non-overlapping sequence of 2^96
numbers (~7*10^28). This is enough to provide 1 billion randoms per
second and per process for 2200 billion years.
The implementation was made thread-safe either by using a double 64-bit
CAS on platforms supporting it (x86_64, aarch64) or by using a local
lock for the time needed to perform the shift operations. This ensures
that all threads pick numbers from the same pool so that it is not
needed to assign per-thread ranges. For processes we use the fast jump
method to advance the sequence by 2^96 for each process.
Before this patch, the following config:
global
nbproc 8
frontend f
bind :4445
mode http
log stdout format raw daemon
log-format "%[uuid] %pid"
redirect location /
Would produce this output:
a4d0ad64-2645-4b74-b894-48acce0669af 12987
a4d0ad64-2645-4b74-b894-48acce0669af 12992
a4d0ad64-2645-4b74-b894-48acce0669af 12986
a4d0ad64-2645-4b74-b894-48acce0669af 12988
a4d0ad64-2645-4b74-b894-48acce0669af 12991
a4d0ad64-2645-4b74-b894-48acce0669af 12989
a4d0ad64-2645-4b74-b894-48acce0669af 12990
82d5f6cd-f6c1-4f85-a89c-36ae85d26fb9 12987
82d5f6cd-f6c1-4f85-a89c-36ae85d26fb9 12992
82d5f6cd-f6c1-4f85-a89c-36ae85d26fb9 12986
(...)
And now produces:
f94b29b3-da74-4e03-a0c5-a532c635bad9 13011
47470c02-4862-4c33-80e7-a952899570e5 13014
86332123-539a-47bf-853f-8c8ea8b2a2b5 13013
8f9efa99-3143-47b2-83cf-d618c8dea711 13012
3cc0f5c7-d790-496b-8d39-bec77647af5b 13015
3ec64915-8f95-4374-9e66-e777dc8791e0 13009
0f9bf894-dcde-408c-b094-6e0bb3255452 13011
49c7bfde-3ffb-40e9-9a8d-8084d650ed8f 13014
e23f6f2e-35c5-4433-a294-b790ab902653 13012
There are multiple benefits to using this method. First, it doesn't
depend anymore on a non-portable API. Second it's thread safe. Third it
is fast and more proven than any hack we could attempt to try to work
around the deficiencies of the various implementations around.
This commit depends on previous patches "MINOR: tools: add 64-bit rotate
operators" and "BUG/MEDIUM: random: initialize the random pool a bit
better", all of which will need to be backported at least as far as
version 2.0. It doesn't require to backport the build fixes for circular
include files dependecy anymore.
This reverts commit 1c306aa84d.
It breaks the build on all non-glibc platforms. I got confused by the
man page (which possibly is the most confusing man page I've ever read
about a standard libc function) and mistakenly understood that random_r
was portable, especially since it appears in latest freebsd source as
well but not in released versions, and with a slightly different API :-/
We need to find a different solution with a fallback. Among the
possibilities, we may reintroduce this one with a fallback relying on
locking around the standard functions, keeping fingers crossed for no
other library function to call them in parallel, or we may also provide
our own PRNG, which is not necessarily more difficult than working
around the totally broken up design of the portable API.
As mentioned in previous patch, the random number generator was never
made thread-safe, which used not to be a problem for health checks
spreading, until the uuid sample fetch function appeared. Currently
it is possible for two threads or processes to produce exactly the
same UUID. In fact it's extremely likely that this will happen for
processes, as can be seen with this config:
global
nbproc 8
frontend f
bind :4445
mode http
log stdout daemon format raw
log-format "%[uuid] %pid"
redirect location /
It typically produces this log:
551ce567-0bfb-4bbd-9b58-cdc7e9365325 30645
551ce567-0bfb-4bbd-9b58-cdc7e9365325 30641
551ce567-0bfb-4bbd-9b58-cdc7e9365325 30644
551ce567-0bfb-4bbd-9b58-cdc7e9365325 30639
551ce567-0bfb-4bbd-9b58-cdc7e9365325 30646
07764439-c24d-4e6f-a5a6-0138be59e7a8 30645
07764439-c24d-4e6f-a5a6-0138be59e7a8 30639
551ce567-0bfb-4bbd-9b58-cdc7e9365325 30643
07764439-c24d-4e6f-a5a6-0138be59e7a8 30646
b6773fdd-678f-4d04-96f2-4fb11ad15d6b 30646
551ce567-0bfb-4bbd-9b58-cdc7e9365325 30642
07764439-c24d-4e6f-a5a6-0138be59e7a8 30642
What this patch does is to use a distinct per-thread and per-process
seed to make sure the same sequences will not appear, and will then
extend these seeds by "burning" a number of randoms that depends on
the global random seed, the thread ID and the process ID. This adds
roughly 20 extra bits of randomness, resulting in 52 bits total per
thread and per process.
It only takes a few milliseconds to burn these randoms and given
that threads start with a different seed, we know they will not
catch each other. So these random extra bits are essentially added
to ensure randomness between boots and cluster instances.
This replaces all uses of random() with ha_random() which uses the
thread-local state.
This must be backported as far as 2.0 or any version having the
UUID sample-fetch function since it's the main victim here.
It's important to note that this patch, in addition to depending on
the previous one "BUG/MEDIUM: init: initialize the random pool a bit
better", also depends on the preceeding build fixes to address a
circular dependency issue in the include files that prevented it
from building. Part or all of these patches may need to be backported
or adapted as well.
Since the UUID sample fetch was created, some people noticed that in
certain virtualized environments they manage to get exact same UUIDs
on different instances started exactly at the same moment. It turns
out that the randoms were only initialized to spread the health checks
originally, not to provide "clean" randoms.
This patch changes this and collects more randomness from various
sources, including existing randoms, /dev/urandom when available,
RAND_bytes() when OpenSSL is available, as well as the timing for such
operations, then applies a SHA1 on all this to keep a 160 bits random
seed available, 32 of which are passed to srandom().
It's worth mentioning that there's no clean way to pass more than 32
bits to srandom() as even initstate() provides an opaque state that
must absolutely not be tampered with since known implementations
contain state information.
At least this allows to have up to 4 billion different sequences
from the boot, which is not that bad.
Note that the thread safety was still not addressed, which is another
issue for another patch.
This must be backported to all versions containing the UUID sample
fetch function, i.e. as far as 2.0.
buffer.h relies on proto/activity because it contains some code and not
just type definitions. It must not be included from types files. It
should probably also be split in two if it starts to include a proto.
This causes some circular dependencies at other places.
In the same way than for the request, when a redirect rule is applied the
transction is aborted. This must be done returning HTTP_RULE_RES_ABRT from
http_res_get_intercept_rule() function.
No backport needed because on previous versions, the action return values are
not handled the same way.
Backend counters must be incremented only if a backend was already assigned to
the stream (when the stream exists). Otherwise, it means we are still on the
frontend side.
This patch may be backported as far as 1.6.
When an action interrupts a transaction, returning a response or not, it must
return the ACT_RET_ABRT value and not ACT_RET_STOP. ACT_RET_STOP is reserved to
stop the processing of the current ruleset.
No backport needed because on previous versions, the action return values are
not handled the same way.
When at least a filter is attached to a stream, FLT_END analyzers must be
preserved on request and response channels.
This patch should be backported as far as 1.7.
Since the HTX mode is the only mode to process HTTP messages, the stream is
created for a uniq transaction. The keep-alive is handled at the mux level. So,
the compression filter can be initialized when the stream is created and
released with the stream. Concretly, .channel_start_analyze and
.channel_end_analyze callback functions are replaced by .attach and .detach
ones.
With this change, it is no longer necessary to call FLT_START_FE/BE and FLT_END
analysers for the compression filter.
Since the HTX mode is the only mode to process HTTP messages, the stream is
created for a uniq transaction. The keep-alive is handled at the mux level. So,
the cache filter can be initialized when the stream is created and released with
the stream. Concretly, .channel_start_analyze and .channel_end_analyze callback
functions are replaced by .attach and .detach ones.
With this change, it is no longer necessary to call FLT_START_FE/BE and FLT_END
analysers for the cache filter.
A typo was introduced by the commit c5bb5a0f2 ("BUG/MINOR: http-rules: Preserve
FLT_END analyzers on reject action").
This patch must be backported with the commit c5bb5a0f2.
When at least a filter is attached to a stream, FLT_END analyzers must be
preserved on request and response channels.
This patch should be backported as far as 1.8.
When an action interrupts a transaction, returning a response or not, it must
return the ACT_RET_ABRT value and not ACT_RET_DONE. ACT_RET_DONE is reserved to
stop the processing on the current channel but some analysers may still be
active. When ACT_RET_ABRT is returned, all analysers are removed, except FLT_END
if it is set.
No backport needed because on previous verions, the action return value was not
handled the same way.
It is stated in the comment the return action returns ACT_RET_ABRT on
success. It it the right code to use to abort a transaction. ACT_RET_DONE must
be used when the message processing must be stopped. This does not means the
transaction is interrupted.
No backport needed.
The wake_time of a lua context is now always set to TICK_ETERNITY when the
context is initialized and when everytime the execution of the lua stack is
started. It is mandatory to not set arbitrary wake_time when an action yields.
No backport needed.
This flag was used in some internal functions to be sure the current stream is
able to handle HTTP content. It was introduced when the legacy HTTP code was
still there. Now, It is possible to rely on stream's flags to be sure we have an
HTX stream.
So the flag HLUA_TXN_HTTP_RDY can be removed. Everywhere it was tested, it is
replaced by a call to the IS_HTX_STRM() macro.
This patch is mandatory to allow the support of the filters written in lua.
In these functions, the lua txn was not used. So it can be removed from the
function argument list.
This patch is mandatory to allow the support of the filters written in lua.
In this function, the lua txn was only used to retrieve the stream. But it can
be retieve from the HTTP message, using its channel pointer. So, the lua txn can
be removed from the function argument list.
This patch is mandatory to allow the support of the filters written in lua.
In this function, the lua txn was only used to test if the HTTP transaction is
defined. But it is always used in a context where it is true. So, the lua txn
can be removed from the function argument list.
This patch is mandatory to allow the support of the filters written in lua.
The Lua function Channel.is_full() should not take care of the reserve because
it is not called from a producer (an applet for instance). From an action, it is
allowed to overwrite the buffer reserve.
This patch should be backported as far as 1.7. But it must be adapted for 1.8
and lower because there is no HTX on these versions.
When a lua action aborts a transaction calling txn:done() function, the action
must return ACT_RET_ABRT instead of ACT_RET_DONE. It is mandatory to
abort the message analysis.
This patch must be backported everywhere the commit 7716cdf45 ("MINOR: lua: Get
the action return code on the stack when an action finishes") was
backported. For now, no backport needed.
When an error occurred on the response side, request analysers must be reset. At
this stage, only AN_REQ_HTTP_XFER_BODY analyser remains, and possibly
AN_REQ_FLT_END, if at least one filter is attached to the stream. So it is safe
to remove the AN_REQ_HTTP_XFER_BODY analyser. An error was already handled and a
response was already returned to the client (or it was at least scheduled to be
sent). So there is no reason to continue to process the request payload. It may
cause some troubles for the filters because when an error occurred, data from
the request buffer are truncated.
This patch must be backported as far as 1.9, for the HTX part only. I don't know
if the legacy HTTP code is affected.
During the payload filtering, the offset is relative to the head of the HTX
message and not its first index. This index is the position of the first block
to (re)start the HTTP analysis. It must be used during HTTP analysis but not
during the payload forwarding.
So, from the compression filter point of view, when we loop on the HTX blocks to
compress the response payload, we must start from the head of the HTX
message. To ease the loop, we use the function htx_find_offset().
This patch must be backported as far as 2.0. It depends on the commit "MINOR:
htx: Add a function to return a block at a specific an offset". So this one must
be backported first.
During the payload filtering, the offset is relative to the head of the HTX
message and not its first index. This index is the position of the first block
to (re)start the HTTP analysis. It must be used during HTTP analysis but not
during the payload forwarding.
So, from the cache point of view, when we loop on the HTX blocks to cache the
response payload, we must start from the head of the HTX message. To ease the
loop, we use the function htx_find_offset().
This patch must be backported as far as 2.0. It depends on the commit "MINOR:
htx: Add a function to return a block at a specific an offset". So this one must
be backported first.
If a filter enable the data filtering, in TCP or in HTTP, but it does not
defined the corresponding callback function (so http_payload() or
tcp_payload()), it will be ignored. If all configured data filter do the same,
we must be sure to forward everything. Otherwise nothing will be forwarded at
all.
This patch must be forwarded as far as 1.9.
When the tcp or http payload is filtered, it is important to use the filter
offset to decude the amount of forwarded data because this offset may change
during the call to the callback function. So we should not rely on a local
variable defined before this call.
For now, existing HAproxy filters don't change this offset, so this bug may only
affect external filters.
This patch must be forwarded as far as 1.9.
The htx_find_offset() function may be used to look for a block at a specific
offset in an HTX message, starting from the message head. A compound result is
returned, an htx_ret structure, with the found block and the position of the
offset in the block. If the offset is ouside of the HTX message, the returned
block is NULL.
The b_insert_blk() function may now be used to insert a string, given a pointer
and the string length, at an absolute offset in a buffer, moving data between
this offset and the buffer's tail just after the end of the inserted string. The
buffer's length is automatically updated. This function supports wrapping. All
the string is copied or nothing. So it returns 0 if there are not enough space
to perform the copy. Otherwise, the number of bytes copied is returned.
This patch fixes PROXYv2 parsing when the payload of the TCP connection is
fused with the PROXYv2 header within a single recv() call.
Previously HAProxy ignored the PROXYv2 header length when attempting to
parse the TLV, possibly interpreting the first byte of the payload as a
TLV type.
This patch adds proper validation. It ensures that:
1. TLV parsing stops when the end of the PROXYv2 header is reached.
2. TLV lengths cannot exceed the PROXYv2 header length.
3. The PROXYv2 header ends together with the last TLV, not allowing for
"stray bytes" to be ignored.
A reg-test was added to ensure proper behavior.
This patch tries to find the sweat spot between a small and easily
backportable one, and a cleaner one that's more easily adaptable to
older versions, hence why it merges the "if" and "while" blocks which
causes a reindent of the whole block. It should be used as-is for
versions 1.9 to 2.1, the block about PP2_TYPE_AUTHORITY should be
dropped for 2.0 and the block about CRC32C should be dropped for 1.8.
This bug was introduced when TLV parsing was added. This happened in commit
b3e54fe387. This commit was first released
with HAProxy 1.6-dev1.
A similar issue was fixed in commit 7209c204bd.
This patch must be backported to HAProxy 1.6+.
James Stroehmann reported something working as documented but that can
be considered as a regression in the way the automatic maxconn is
calculated from the process' limits :
https://www.mail-archive.com/haproxy@formilux.org/msg36523.html
The purpose of the changes in 2.0 was to have maxconn default to the
highest possible value permitted to the user based on the ulimit -n
setting, however the calculation starts from the soft limit, which
can be lower than what users were allowed to with previous versions
where the default value of 2000 would force a higher ulimit -n as
long as it fitted in the hard limit.
Usually this is not noticeable if the user changes the limits, because
quite commonly setting a new value restricts both the soft and hard
values.
Let's instead always use the max between the hard and soft limits, as
we know these values are permitted. This was tried on the following
setup:
$ cat ulimit-n.cfg
global
stats socket /tmp/sock1 level admin
$ ulimit -n
1024
Before the change the limits would show like this:
$ socat - /tmp/sock1 <<< "show info" | grep -im2 ^Max
Maxsock: 1023
Maxconn: 489
After the change the limits are now much better and more in line with
the default settings in earlier versions:
$ socat - /tmp/sock1 <<< "show info" | grep -im2 ^Max
Maxsock: 4095
Maxconn: 2025
The difference becomes even more obvious when running moderately large
configs with hundreds of checked servers and hundreds of listeners:
$ cat ulimit-n.cfg
global
stats socket /tmp/sock1 level admin
listen l
bind :10000-10300
server-template srv- 300 0.0.0.0 check disabled
Before After
Maxsock 1024 4096
Maxconn 189 1725
This issue is tagged as minor since a trivial config change fixes it,
but it would help new users to have it backported as far as 2.0.
pattern_finalize_config() uses an inefficient algorithm which is a
problem with very large configuration files. This affects startup, and
therefore reload time. When haproxy is deployed as a router in a
Kubernetes cluster the generated configuration file may be large and
reloads are frequently occuring, which makes this a significant issue.
The old algorithm is O(n^2)
* allocate missing uids - O(n^2)
* sort linked list - O(n^2)
The new algorithm is O(n log n):
* find the user allocated uids - O(n)
* store them for efficient lookup - O(n log n)
* allocate missing uids - n times O(log n)
* sort all uids - O(n log n)
* convert back to linked list - O(n)
Performance examples, startup time in seconds:
pat_refs old new
1000 0.02 0.01
10000 2.1 0.04
20000 12.3 0.07
30000 27.9 0.10
40000 52.5 0.14
50000 77.5 0.17
Please backport to 1.8, 2.0 and 2.1.
`istalloc` allocates memory and returns an `ist` with the size `0` that points
to this allocation.
`istfree` frees the pointed memory and clears the pointer.
