The stopping-list management introduced by commit d3a88c1c3 ("MEDIUM:
connection: close front idling connection on soft-stop") missed two
error paths in the H1 and H2 muxes. The effect is that if a stream
or HPACK table couldn't be allocated for these incoming connections,
we would leave with the connection freed still attached to the
stopping_list and it would never leave it, resulting in use-after-free
hence either a crash or a data corruption.
This is marked as medium as it only happens under extreme memory pressure
or when playing with tune.fail-alloc. Other stability issues remain in
such a case so that abnormal behaviors cannot be explained by this bug
alone.
This must be backported to 2.4.
During 2.4-dev, an issue with partial frames was fixed with commit
3d4631fec ("BUG/MEDIUM: mux-h2: fix read0 handling on partial frames").
However this patch is not completely correct. It makes h2_recv() return
0 if the connection was shut for reads, but this not make h2_io_cb()
call h2_process(), so if there are any pending data left in the demux
buffer, they will never be processed, and the I/O callback will be
called in loops forever from the poller.
The correct return value there is 1, as is done at the end of the
function to report a pending read0.
This should definitely fix issue #1328. However even after a lot of
tests I couldn't manage to reproduce it, the conditions to enter that
situation are quite racy.
This must be backported to 2.0 since the fix above was merged into
2.0.21 and 2.2.9.
The value for H2_CF_DEM_SHORT_READ flag is wrong. 2 bits are erroneously
set, 0x200 and 0x80000. It is not an issue because both bits are not used
anywhere else.
The typo was introduced in the commit b5f7b5296 ("BUG/MEDIUM: mux-h2: Handle
remaining read0 cases on partial frames"). Thus this patch must also be
backported as far a 2.0.
Define a new stream flag SF_WEBSOCKET and a new cs flag CS_FL_WEBSOCKET.
The conn-stream flag is first set by h1/h2 muxes if the request is a
valid websocket upgrade. The flag is then converted to SF_WEBSOCKET on
the stream creation.
This will be useful to properly manage websocket streams in
connect_server().
The RFC8441 was not respected by haproxy in regards with server support
for Extended CONNECT. The Extended CONNECT method was used to convert an
Upgrade header stream even if no SETTINGS_ENABLE_CONNECT_PROTOCOL was
received, which is forbidden by the RFC8441. In this case, the behavior
of the http/2 server is unspecified.
Fix this by flagging the connection on receiption of the RFC8441
settings SETTINGS_ENABLE_CONNECT_PROTOCOL. Extended CONNECT is thus only
be used if the flag is present. In the other case, the stream is
immediatly closed as there is no way to handle it in http/2. It results
in a http/1.1 502 or http/2 RESET_STREAM to the client side.
The protocol-upgrade regtest has been extended to test that haproxy does
not emit Extended CONNECT on servers without RFC8441 support.
It must be backported up to 2.4.
Add a state trace to report that a protocol upgrade is converted using
the rfc8441 Extended connect method. This is useful in regards with the
recent changes to improve http/2 websockets.
While in H1 we can usually close quickly, in H2 a client might be sending
window updates or anything while we're sending a GOAWAY and the pending
data in the socket buffers at the moment the close() is performed on the
socket results in the output data being lost and an RST being emitted.
One example where this happens easily is with h2spec, which randomly
reports connection resets when waiting for a GOAWAY while haproxy sends
it, as seen in issue #1422. With h2spec it's not window updates that are
causing this but the fact that h2spec has to upload the payload that
comes with invalid frames to accommodate various implementations, and
does that in two different segments. When haproxy aborts on the invalid
frame header, the payload was not yet received and causes an RST to
be sent.
Here we're dealing with this two ways:
- we perform a shutdown(WR) on the connection to forcefully push pending
data on a front connection after the xprt is shut and closed ;
- we drain pending data
- then we close
This totally solves the issue with h2spec, and the extra cost is very
low, especially if we consider that H2 connections are not set up and
torn down often. This issue was never observed with regular clients,
most likely because this pattern does not happen in regular traffic.
After more testing it could make sense to backport this, at least to
avoid reporting errors on h2spec tests.
Some checks were added by commit 9a3d3fcb5 ("BUG/MAJOR: mux-h2: Don't try
to send data if we know it is no longer possible") to make sure we don't
loop forever trying to send data that cannot leave. But one of the
conditions there is not correct, the one relying on H2_CS_ERROR2. Indeed,
this state indicates that the error code was serialized into the mux
buffer, and since the test is placed before trying to send the data to
the socket, if the connection states only contains a GOAWAY frame, it
may refrain from sending and may close without sending anything. It's
not dramatic, as GOAWAY reports connection errors in situations where
delivery is not even certain, but it's cleaner to make sure the error
is properly sent, and it avoids upsetting h2spec, as seen in github
issue #1422.
Given that the patch above was backported as far as 1.8, this patch will
also have to be backported that far.
Thanks to Ilya for reporting this one.
This change is required to support TCP/HTTP rules in defaults sections. The
'disabled' bitfield in the proxy structure, used to know if a proxy is
disabled or stopped, is replaced a generic bitfield named 'flags'.
PR_DISABLED and PR_STOPPED flags are renamed to PR_FL_DISABLED and
PR_FL_STOPPED respectively. In addition, everywhere there is a test to know
if a proxy is disabled or stopped, there is now a bitwise AND operation on
PR_FL_DISABLED and/or PR_FL_STOPPED flags.
The last 3 fields were 3 list heads that are per-thread, and which are:
- the pool's LRU head
- the buffer_wq
- the streams list head
Moving them into thread_ctx completes the removal of dynamic elements
from the struct thread_info. Now all these dynamic elements are packed
together at a single place for a thread.
We've found others places where the read0 is ignored because of an
incomplete frame parsing. This time, it happens during parsing of
CONTINUATION frames.
When frames are parsed, incomplete frames are properly handled and
H2_CF_DEM_SHORT_READ flag is set. It is also true for HEADERS
frames. However, for CONTINUATION frames, there is an exception. Besides
parsing the current frame, we try to peek header of the next one to merge
payload of both frames, the current one and the next one. Idea is to create
a sole HEADERS frame before parsing the payload. However, in this case, it
is possible to have an incomplete frame too, not the current one but the
next one. From the demux point of view, the current frame is complete. We
must go to the internal function h2c_decode_headers() to detect an
incomplete frame. And this case was not identified and fixed when
H2_CF_DEM_SHORT_READ flag was introduced in the commit b5f7b5296
("BUG/MEDIUM: mux-h2: Handle remaining read0 cases on partial frames")
This bug was reported in a comment of the issue #1362. The patch must be
backported as far as 2.0.
backend.c, all muxes, backend.c started manipulating ebmb_nodes with
the introduction of idle conns but the types were inherited through
other includes. Let's add ebmbtree.h there.
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.
The transient flag CO_RFL_BUF_NOT_STUCK should now be set when the mux's
rcv_buf() function is called, in si_cs_recv(), to be sure the mux is able to
perform some optimisation during data copy. This flag is set when we are
sure the channel buffer is not stuck. Concretely, it happens when there are
data scheduled to be sent.
It is not a fix and this flag is not used for now. But it makes sense to have
this info to be sure to be able to do some optimisations if necessary.
This patch is related to the issue #1362. It may be backported to 2.4 to
ease future backports.
Instead of returning a 501-Not-implemented error when "Ugrade:" header is
found for a request with a payload, the header is removed. This way, the
upgrade is disabled and the request is still sent to the server. It is
required because some frameworks seem to try to perform H2 upgrade on every
requests, including POST ones.
The h2 mux was slightly fixed to convert Upgrade requests to extended
connect ones only if the rigth HTX flag is set.
This patch should fix the issue #1381. It must be backported to 2.4.
This part was fixed several times since commit aade4edc1 ("BUG/MEDIUM:
mux-h2: Don't handle pending read0 too early on streams") and there are
still some cases where a read0 event may be ignored because a partial frame
inhibits the event.
Here, we must take care to set H2_CF_END_REACHED flag if a read0 was
received while a partial frame header is received or if the padding length
is missing.
To ease partial frame detection, H2_CF_DEM_SHORT_READ flag is introduced. It
is systematically removed when some data are received and is set when a
partial frame is found or when dbuf buffer is empty. At the end of the
demux, if the connection must be closed ASAP or if data are missing to move
forward, we may acknowledge the pending read0 event, if any. For now,
H2_CF_DEM_SHORT_READ is not part of H2_CF_DEM_BLOCK_ANY mask.
This patch should fix the issue #1328. It must be backported as far as 2.0.
If a connection is closed during the preface while no data are received, if
the dontlognull option is set, no log message must be emitted. However, this
will still be handled as a protocol error. Only the log is omitted.
This patch should fix the issue #1336 for H2 sessions. It must be backported
to 2.4 and 2.3 at least, and probably as far as 2.0.
Define a new global config statement named
"h2-workaround-bogus-websocket-clients".
This statement will disable the automatic announce of h2 websocket
support as specified in the RFC8441. This can be use to overcome clients
which fail to implement the relatively fresh RFC8441. Clients will in
his case automatically downgrade to http/1.1 for the websocket tunnel
if the haproxy configuration allows it.
This feature is relatively simple and can be backported up to 2.4, which
saw the introduction of h2 websocket support.
In 2.4, commit d1ac2b90c ("MAJOR: htx: Remove the EOM block type and
use HTX_FL_EOM instead") changed the HTX processing to destroy the
blocks as they are processed. So the traces that were emitted at the
end of the send headers functions didn't have anything to show.
Let's move these traces earlier in the function, right before the HTX
processing, so that everything is still in place.
This should be backported to 2.4.
Since commit 7d013e796 ("BUG/MEDIUM: mux-h2: Xfer rxbuf to the upper
layer when creating a front stream"), the rxbuf is lost during the
call to h2c_frt_stream_new(), so the trace that happens later cannot
find a request there and we've lost the useful part indicating what
the request looked like. Let's move the trace before this call.
This should be backported to 2.4.
We're seeing some browsers setting up multiple connections and closing
some to just keep one. It looks like they do this in case they'd
negotiate H1. This results in aborted prefaces and log pollution about
bad requests and "PR--" in the status flags.
We already have an option to ignore connections with no data, it's called
http-ignore-probes. But it was not used by the H2 mux. However it totally
makes sense to use it during the preface.
This patch changes this so that connections aborted before sending the
preface can avoid being logged.
This should be backported to 2.4 and 2.3 at least, and probably even
as far as 2.0.
"sent H2 request" was already misaligned with the 3 other ones
(sent/rcvd, request/response), and now with "new H2 connection" that's
yet another alignment making the traces even less legible. Let's just
realign all 5 messages, this even eases quick pointer comparisons. This
should probably be backported to 2.4 as it's where it's the most likely
to be used in the mid-term.
It is currently very difficult to match some H2 trace outputs against
some log extracts because there's no exactly equivalent info.
This patch tries to address this by adding a TRACE_USER() call in h2_init()
that is matched in h2_trace() to report:
- connection pointer and direction
- frontend's name or server's name
- transport layer and control layer (e.g. "SSL/tcpv4")
- source and/or destination depending on what is set
This now permits to get something like this at verbosity level complete:
<0>2021-06-16T18:30:19.810897+02:00 [00|h2|1|mux_h2.c:1006] new H2 connection : h2c=0x19fee50(F,PRF) : conn=0x7f373c026850(IN) fe=h2gw RAW/tcpv4 src=127.0.0.1:19540
<0>2021-06-16T18:30:19.810919+02:00 [00|h2|1|mux_h2.c:2731] rcvd H2 request : h2c=0x19fee50(F,FRH)
<0>2021-06-16T18:30:19.810998+02:00 [00|h2|1|mux_h2.c:1006] new H2 connection : h2c=0x1a04ee0(B,PRF) : conn=0x1a04ce0(OUT) sv=h2gw/s1 RAW/tcpv4 dst=127.0.0.1:4446
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.
When a DATA frame is sent, we must take care to properly detect the EOM flag
on the HTX message to set ES flag on the frame when necessary, to finish the
stream. But it is only done when data are copied from the HTX message to the
mux buffer and not when the frame are sent via a zero-copy. This patch fixes
this bug.
It is a 2.4-specific bug. No backport is needed.
Since the input buffer is transferred to the stream when it is created,
there is no longer control on the request size to be sure the buffer's
reserve is still respected. It was automatically performed in h2_rcv_buf()
because the caller took care to provide the correct available space in the
buffer. The control is still there but it is no longer applied on the
request headers. Now, we should take care of the reserve when the headers
are decoded, before the stream creation.
The test is performed for the request and the response.
It is a 2.4-specific bug. No backport is needed.
The H2_CF_RCVD_SHUT flag is used to report a read0 was encountered. It is
used by the H2 mux to properly handle shutdowns. However, this flag is only
set when no data are received. If it is detected at the socket level when
some data are received, it is not handled. And because the event was
reported on the connection, any other read attempts are blocked. In this
case, we are unable to close the connection and release the mux
immediately. We must wait the mux timeout expires.
This patch should fix the issue #1231. It must be backported as far as 2.0.
When header are splitted over several frames, payload of HEADERS and
CONTINUATION frames are merged to form a unique HEADERS frame before
decoding the payload. To do so, info about the current frame are updated
(dff, dfl..) with info of the next one. Here there is a bug when the frame
length (dfl) is update. We must add the next frame length (hdr.dfl) and not
only the amount of data found in the buffer (clen). Because HEADERS frames
are decoded in one pass, dfl value is the whole frame length or 0. nothing
intermediary.
This patch must be backported as far as 2.0.
In the function decoding payload of HEADERS frames, an internal error is
returned if the frame length is too large. it cannot exceed the buffer
size. The same is true when headers are splitted on several frames. The
payload of HEADERS and CONTINUATION frames are merged and the overall size
must not exceed the buffer size.
However, there is a bug when the current frame is big enough to only have
the space for a part of the header of the next frame. Because, in this case,
we wait for more data, to have the whole frame header. We don't properly
detect that the headers are too large to be stored in one buffer. In fact
the test to trigger this error is not accurate. When the buffer is full, the
error is reported if the frame length exceeds the amount of data in the
buffer. But in reality, an error must be reported when we are unable to
decode the current frame while the buffer is full. Because, in this case, we
know there is no way to change this state.
When the bug happens, the H2 connection is woken up in loop, consumming all
the CPU. But the traffic is not blocked for all that.
This patch must be backported as far as 2.0.
The current "ADD" vs "ADDQ" is confusing because when thinking in terms
of appending at the end of a list, "ADD" naturally comes to mind, but
here it does the opposite, it inserts. Several times already it's been
incorrectly used where ADDQ was expected, the latest of which was a
fortunate accident explained in 6fa922562 ("CLEANUP: stream: explain
why we queue the stream at the head of the server list").
Let's use more explicit (but slightly longer) names now:
LIST_ADD -> LIST_INSERT
LIST_ADDQ -> LIST_APPEND
LIST_ADDED -> LIST_INLIST
LIST_DEL -> LIST_DELETE
The same is true for MT_LISTs, including their "TRY" variant.
LIST_DEL_INIT keeps its short name to encourage to use it instead of the
lazier LIST_DELETE which is often less safe.
The change is large (~674 non-comment entries) but is mechanical enough
to remain safe. No permutation was performed, so any out-of-tree code
can easily map older names to new ones.
The list doc was updated.
This patch replaces roughly all occurrences of an HA_ATOMIC_ADD(&foo, 1)
or HA_ATOMIC_SUB(&foo, 1) with the equivalent HA_ATOMIC_INC(&foo) and
HA_ATOMIC_DEC(&foo) respectively. These are 507 changes over 45 files.
MX_FL_NO_UPG flag may now be set on a multiplexer to explicitly disable
upgrades from this mux. For now, it is set on the FCGI multiplexer because
it is not supported and there is no upgrade on backend-only multiplexers. It
is also set on the H2 multiplexer because it is clearly not supported.
sess_log() was called twice if an error occurred on the preface parsing, in
h2c_frt_recv_preface() and in h2_process_demux().
This patch must be backported as far as 2.0.
The function's purpose used to be to fail a buffer allocation if that
allocation wouldn't result in leaving some buffers available. Thus,
some allocations could succeed and others fail for the sole purpose of
trying to provide 2 buffers at once to process_stream(). But things
have changed a lot with 1.7 breaking the promise that process_stream()
would always succeed with only two buffers, and later the thread-local
pool caches that keep certain buffers available that are not accounted
for in the global pool so that local allocators cannot guess anything
from the number of currently available pools.
Let's just replace all last uses of b_alloc_margin() with b_alloc() once
for all.
When tasklets were derived from tasks, there was no immediate need for
the scheduler to know their status after execution, and in a spirit of
simplicity they just started to always return NULL. The problem is that
it simply prevents the scheduler from 1) accounting their execution time,
and 2) keeping track of their current execution status. Indeed, a remote
wake-up could very well end up manipulating a tasklet that's currently
being executed. And this is the reason why those handlers have to take
the idle lock before checking their context.
In 2.5 we'll take care of making tasklets and tasks work more similarly,
but trouble is to be expected if we continue to propagate the trend of
returning NULL everywhere, especially if some fixes relying on a stricter
model later need to be backported. For this reason this patch updates all
known tasklet handlers to make them return NULL only when the tasklet was
freed. It has no effect for now and isn't even guaranteed to always be
100% safe but it puts the code into the right direction for this.
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.
These functions are used on the mux layer to indicate that the connection
is becoming idle and that the xprt ought to be careful before checking the
context or that it's not idle anymore and that the context is safe. The
purpose is to allow a mux which is going to release a connection to tell
the xprt to be careful when touching it. At the moment, the xprt are
always careful and that's costly so we want to have the ability to relax
this a bit.
No xprt layer uses this yet.
The muxes are touching the idle_conns_lock all the time now because
they need to be careful that no other thread has stolen their tasklet's
context.
This patch changes this a little bit by setting the TASK_F_USR1 flag on
the tasklet before marking a connection idle, and removing it once it's
not idle anymore. Thanks to this we have the guarantee that a tasklet
without this flag cannot be present in an idle list and does not need
to go through this costly lock. This is especially true for front
connections.
It's been too short for quite a while now and is now full. It's still
time to extend it to 32-bits since we have room for this without
wasting any space, so we now gained 16 new bits for future flags.
The values were not reassigned just in case there would be a few
hidden u16 or short somewhere in which these flags are placed (as
it used to be the case with stream->pending_events).
The patch is tagged MEDIUM because this required to update the task's
process() prototype to use an int instead of a short, that's quite a
bunch of places.
One location was not matched due to a typo. Reapply the patch for consistency.
see 92c696e663ab4bbcffd5dc0afedf1d0afd1c7279
see a3298023b04923ba12429d79c559dc7a850ae122
That comma should've been a semicolon. Fortunately, as it is now there
is no impact thanks to operators precedence, and all expressions are
properly evaluated. But this is troubling and the risk is high to
turn it into an effective bug with a minor change.
Introduced in b8ce8905cf63ecd06b36af39c05103fadf3cc347 which first
appeared in 2.1-dev3. This fix must be backported to 2.1+.
In H1, H2 and FCGI muxes, in the show_fd function, there is duplicated test on
the stream's subs field.
This patch fixes the issue #1142. It may be backported as far as 2.2.
Historically this function would try to wake the most accurate number of
process_stream() waiters. But since the introduction of filters which could
also require buffers (e.g. for compression), things started not to be as
accurate anymore. Nowadays muxes and transport layers also use buffers, so
the runqueue size has nothing to do anymore with the number of supposed
users to come.
In addition to this, the threshold was compared to the number of free buffer
calculated as allocated minus used, but this didn't work anymore with local
pools since these counts are not updated upon alloc/free!
Let's clean this up and pass the number of released buffers instead, and
consider that each waiter successfully called counts as one buffer. This
is not rocket science and will not suddenly fix everything, but at least
it cannot be as wrong as it is today.
This could have been marked as a bug given that the current situation is
totally broken regarding this, but this probably doesn't completely fix
it, it only goes in a better direction. It is possible however that it
makes sense in the future to backport this as part of a larger series if
the situation significantly improves.
The buffer wait queue used to be global historically but this doest not
make any sense anymore given that the most common use case is to have
thread-local pools. Thus there's no point waking up waiters of other
threads after releasing an entry, as they won't benefit from it.
Let's move the queue head to the thread_info structure and use
ti->buffer_wq from now on.
