This mmaps a file which will serve as the backing-store for the ring's
contents. The idea is to provide a way to retrieve sensitive information
(last logs, debugging traces) even after the process stops and even after
a possible crash. Right now this was possible by connecting to the CLI
and dumping the contents of the ring live, but this is not handy and
consumes quite a bit of resources before it is needed.
With a backing file, the ring is effectively RAM-mapped file, so that
contents stored there are the same as those found in the file (the OS
doesn't guarantee immediate sync but if the process dies it will be OK).
Note that doing that on a filesystem backed by a physical device is a
bad idea, as it will induce slowdowns at high loads. It's really
important that the device is RAM-based.
Also, this may have security implications: if the file is corrupted by
another process, the storage area could be corrupted, causing haproxy
to crash or to overwrite its own memory. As such this should only be
used for debugging.
Instead of allocating two parts, one for the ring struct itself and
one for the storage area, ring_make_from_area() will arrange the two
inside the same memory area, with the storage starting immediately
after the struct. This will allow to store a complete ring state in
shared memory areas for example.
This commit was not complete:
"BUG/MEDIUM: quic: Possible use of uninitialized <odcid>
variable in qc_lstnr_params_init()"
<token_odcid> should have been directly passed to qc_lstnr_params_init()
without dereferencing it to prevent haproxy to have new chances to crash!
Must be backported to 2.6.
It took me a while to figure why a ring declared with "size 1M" was causing
strange effects in a ring, it's just because it's parsed as "1", which is
smaller than the default 16384 size and errors are silently ignored.
This commit tries to address this the best possible way without breaking
existing configs that would work by accident, by warning that the size is
ignored if it's smaller than the current one, and by printing the parsed
size instead of the input string in warnings and errors. This way if some
users have "size 10000" or "size 100k" it will continue to work as 16kB
like today but they will now be aware of it.
In addition the error messages were a bit poor in context in that they
only provided line numbers. The ring name was added to ease locating the
problem.
As the issue was present since day one and was introduced in 2.2 with
commit 99c453df9d ("MEDIUM: ring: new section ring to declare custom ring
buffers."), it could make sense to backport this as far as 2.2, but with
2.2 being quite old now it doesn't seem very reasonable to start emitting
new config warnings in config that apparently worked well.
Thus it looks more reasonable to backport this as far as 2.4.
When receiving a token into a client Initial packet without a cluster secret defined
by configuration, the <odcid> variable used to parse the ODCID from the token
could be used without having been initialized. Such a packet must be dropped. So
the sufficient part of this patch is this check:
+ }
+ else if (!global.cluster_secret && token_len) {
+ /* Impossible case: a token was received without configured
+ * cluster secret.
+ */
+ TRACE_PROTO("Packet dropped", QUIC_EV_CONN_LPKT,
+ NULL, NULL, NULL, qv);
+ goto drop;
}
Take the opportunity of this patch to rework and make it more readable this part
of code where such a packet must be dropped removing the <check_token> variable.
When an ODCID is parsed from a token, new <token_odcid> new pointer variable
is set to the address of the parsed ODCID. This way, is not set but used it will
make crash haproxy. This was not always the case with an uninitialized local
variable.
Adapt the API to used such a pointer variable: <token> boolean variable is removed
from qc_lstnr_params_init() prototype.
This must be backported to 2.6.
Traces argument were incorrectly used in qcs_free(). A qcs was specified
as first arg instead of a connection. This will lead to a crash if
developer qmux traces are activated. This is now fixed.
This bug has been introduced with QUIC MUX traces rework. No need to
backport.
Add new traces to help debugging on QUIC MUX. Most notable, the
following functions are now traced :
* qcc_emit_cc
* qcs_free
* qcs_consume
* qcc_decode_qcs
* qcc_emit_cc_app
* qcc_install_app_ops
* qcc_release_remote_stream
* qcc_streams_sent_done
* qc_init
Change default devel level for some traces in QUIC MUX:
* proto : used to notify about reception/emission of frames
* state : modification of internal state of connection or streams
* data : detailled information about transfer and flow-control
Replace devel traces with error level on all errors situation. Also a
new event QMUX_EV_PROTO_ERR is used. This should help to detect invalid
situations quickly.
This loop is due to the fact that we do not select the next node before
the conditional "continue" statement. Furthermore the condition and the
"continue" statement may be removed after replacing eb64_first() call
by eb64_lookup_ge(): we are sure this condition may not be satisfied.
Add some comments: this function initializes connection IDs with sequence
number 1 upto <max> non included.
Take the opportunity of this patch to remove a "return" wich broke this
traces rule: for any function, do not call TRACE_ENTER() without TRACE_LEAVE()!
Add also TRACE_ERROR() for any encoutered errors.
Must be backported to 2.6
This lock was there be able to handle the RX packets for a connetion
from several threads. This is no more needed since a QUIC connection
is always handled by the same thread.
May be backported to 2.6
gcc-6.x and 7.x emit build warnings about sc possibly being null upon
return from sc_detach_endp(). This actually is not the case and the
compiler is a little bit overzealous there, but there exists code
paths that can make this analysis non-trivial so let's at least add
a similar BUG_ON() to let both the compiler and the deverloper know
this doesn't happen.
This should be backported to 2.6.
Add a least as much as possible TRACE_ENTER() and TRACE_LEAVE() calls
to any function. Note that some functions do not have any access to the
a quic_conn argument when receiving or parsing datagram at very low level.
The poller pipes needed to communicate between multiple threads are
allocated in init_pollers_per_thread() and released in
deinit_pollers_per_thread(). The former adds them via fd_insert()
so that they are known, but the former only closes them using a
regular close().
This asymmetry represents a problem, because we have in the fdtab[]
an entry for something that may disappear when one thread leaves, and
since these FD numbers are very low, there is a very high likelihood
that they are immediately reassigned to another thread trying to
connect() to a server or just sending a health check. In this case,
the other thread is going to fd_insert() the fd and the recently
added consistency checks will notive that ->owner is not NULL and
will crash. We just need to use fd_delete() here to match fd_insert().
Note that this test was added in 2.7-dev2 by commit 36d9097cf
("MINOR: fd: Add BUG_ON checks on fd_insert()") which was backported
to 2.4 as a safety measure (since it allowed to catch particularly
serious issues). The patch in itself isn't wrong, it just revealed
a long-dormant bug (been there since 1.9-dev1, 4 years ago). As such
the current patch needs to be backported wherever the commit above
is backported.
Many thanks to Christian Ruppert for providing detailed traces in
github issue #1807 and Cedric Paillet for bringing his complementary
analysis that helped to understand the required conditions for this
issue to happen (fast health checks @100ms + randomly long connections
~7s + fast reloads every second + hard-stop-after 5s were necessary
on the dev's machine to trigger it from time to time).
Fred managed to reproduce a crash showing a corrupted accept_list when
firing thousands of concurrent picoquicdemo clients to a same instance.
It may happen if the connection was placed into the accept_list and
immediately closed before being processed (e.g. on error or t/o ?).
In any case the quic_conn_release() function should always detach a
connection to be deleted from any list, like it does for other lists,
so let's add an MT_LIST_DELETE() here.
This should be backported to 2.6.
When arriving at the handshake completion, next encryption level will be
null on quic_conn_io_cb(). Thus this must be check this before
dereferencing it via qc_need_sending() to prevent a crash.
This was reproduced quickly when browsing over a local nextcloud
instance through QUIC with firefox.
This has been introduced in the current dev with quic-conn Tx
refactoring. No need to backport it.
Considered a stream as opened when receiving a STOP_SENDING frame as the
first frame on the stream.
This patch is tagged as BUG because a BUG_ON may occur if only a
STOP_SENDING frame has been received for a frame. This will reset the
stream in respect with RFC9000 but internally it is considered invalid
transition to reset an idle stream.
To fix this, simply use qcs_idle_open() on STOP_SENDING parsing
function. This will mark the stream as OPEN before resetting it.
This was detected on haproxy.org with the following backtrace :
FATAL: bug condition "qcs->st == QC_SS_IDLE" matched at
src/mux_quic.c:383
call trace(12):
| 0x490dd3 [b8 01 00 00 00 c6 00 00]: main-0x1d0633
| 0x4975b8 [48 8b 85 58 ff ff ff 8b]: main-0x1c9e4e
| 0x497df4 [48 8b 45 c8 48 89 c7 e8]: main-0x1c9612
| 0x49934c [48 8b 45 c8 48 89 c7 e8]: main-0x1c80ba
| 0x6b3475 [48 8b 05 54 1b 3a 00 64]: run_tasks_from_lists+0x45d/0x8b2
| 0x6b4093 [29 c3 89 d8 89 45 d0 83]: process_runnable_tasks+0x7c9/0x824
| 0x660bde [8b 05 fc b3 4f 00 83 f8]: run_poll_loop+0x74/0x430
| 0x6611de [48 8b 05 7b a6 40 00 48]: main-0x228
| 0x7f66e4fb2ea5 [64 48 89 04 25 30 06 00]: libpthread:+0x7ea5
| 0x7f66e455ab0d [48 89 c7 e8 5b 72 fc ff]: libc:clone+0x6d/0x86
Stream states have been implemented in the current dev tree. Thus, this
patch does not need to be backported.
Check on quic_conn_io_cb() if sending is required. This allows to skip
over Tx buffer allocation if not needed.
To implement this, we check if frame lists on current and next
encryption level are empty. We also need to check if there is no need to
send ACK, PROBE or CONNECTION_CLOSE. This has been isolated in a new
function qc_need_sending() which may be reuse in some other functions in
the future.
This is the final patch on quic-conn Tx refactor. Extend the function
which is used to write a datagram header to save at the same time
written buffer data. This makes sense as the two operations are used at
the same occasion when a pre-written datagram is comitted.
Complete refactor of quic-conn Tx buffer. The buffer is now released
on every send operation completion. This should help to reduce memory
footprint as now Tx buffers are allocated and released on demand.
To simplify allocation/free of quic-conn Tx buffer, two static functions
are created named qc_txb_alloc() and qc_txb_release().
On first prototype version of QUIC, emission was multithreaded. To
support this, a custom thread-safe ring-buffer has been implemented with
qring/cbuf.
Now the thread model has been adjusted : a quic-conn is always used on
the same thread and emission is not multi-threaded. Thus, qring/cbuf
usage can be replace by a standard struct buffer.
The code has been simplified even more as for now buffer is always
drained after a prepare/send invocation. This is the case since a
datagram is always considered as sent even on sendto() error. BUG_ON
statements guard are here to ensure that this model is always valid.
Thus, code to handle data wrapping and consume too small contiguous
space with a 0-length datagram is removed.
qc_send_app_pkts() has now a while loop implemented which allows to send
all possible frames even if the send buffer is full between packet
prepare and send. This is present since commit :
dc07751ed7
MINOR: quic: Send packets as much as possible from qc_send_app_pkts()
This means we can remove code from the MUX which implement this at the
upper layer. This is useful to simplify qc_send_frames() function.
As mentionned commit is subject to backport, this commit should be
backported as well to 2.6.
The first column's width may vary a lot depending on outputs, and it's
annoying to have large empty columns on small names and mangled large
columns that are not yet large enough. In order to overcome this, this
patch adds a width field to the memstats applet's context, and this
width is calculated the first time the function is entered, by estimating
the width of all lines that will be dumped. This is simple enough and
does the job well. If in the future some filtering criteria are added,
it will still be possible to perform a single pass on everything
depending on the desired output format.
The calling function name is now stored in the structure, and it's
reported when the "all" argument is passed. The first column is
significantly enlarged because some names are really wide :-(
These fake datagrams are only used by the low level I/O handler. They
are not provided to the "by connection" datagram handlers. This
is why they are not MT_LIST_APPEND()ed to the listner RX buffer list
(see &quic_dghdlrs[cid_tid].dgrams in quic_lstnr_dgram_dispatch().
Replace the call to pool_zalloc() to by the lighter call to pool_malloc()
and initialize only the ->buf and ->length members. This is safe because
only these fields are inspected by the low level I/O handler.
After removing the packet header protection, we can check the packet is long
enough to contain a 16 bytes length AEAD TAG (at this end of the packet).
This test was missing.
Must be backported to 2.6.
These traces about the available room into the packet currently built and
its payload length could be displayed for each STREAM frame, even for
those which have no chance to be embedded into a packet leading to
very traces to be displayed from a connection with a lot of stream.
This was revealed by traces provide by Tristan in GH #1808
May be backported to 2.6.
When entering this function, we first check the packet length is not too short.
But this was done against the datagram lenght in place of the packet length.
This could lead to the header protection to be removed using data past
the end of the packet (without buffer overflow).
Use the packet length in place of the datagram length which is at <end>
address passed as parameter to this function. As the packet length
is already stored in ->len packet struct member, this <end> parameter is no
more useful.
Must be backported to 2.6.
_GNU_SOURCE used to be defined only when USE_LIBCRYPT was set. It's also
needed for sched_setaffinity() to be exported. As a side effect, when
USE_LIBCRYPT is not set, a warning is emitted, as Ilya found and reported
in issue #1815. Let's just define _GNU_SOURCE regardless of USE_LIBCRYPT,
and also explicitly add sched.h, as right now it appears to be inherited
from one of the other includes.
This should be backported to 2.4.
dh of length 1024 were chosen for EVP_PKEY_EC key type.
let us pick "default_dh_param" instead.
issue was found on Ubuntu 22.04 which is shipped with OpenSSL configured
with SECLEVEL=2 by default. such SECLEVEL value prohibits DH shorter than
2048:
OpenSSL error[0xa00018a] SSL_CTX_set0_tmp_dh_pkey: dh key too small
better strategy for chosing DH still may be considered though.
The function processes packets sent by other threads in the current
thread's queue. But if, for any reason, other threads write faster
than the current one processes, this can lead to a situation where
the function never returns.
It seems that it might be what's happening in issue #1808, though
unfortunately, this function is one of the rare without traces. But
the amount of calls to functions like qc_lstnr_pkt_rcv() on a single
thread seems to indicate this possibility.
Thanks to Tristan for his efforts in collecting extremely precious
traces!
This likely needs to be backported to 2.6.
qc_snd_buf returned a size_t which means that it was never negative
despite its documentation. Thus the caller who checked for this was
never informed of a sendto error.
Clean this by changing the return value of qc_snd_buf() to an integer.
A 0 is returned on success. Every other values are considered as an
error.
This commit should be backported up to 2.6. Note that to not cause
malfunctions, it must be backported after the previous patch :
906b058954
MINOR: quic: explicitely ignore sendto error
This is to ensure that a sendto error does not cause send to be
interrupted which may cause a stalled transfer without a proper retry
mechanism.
The impact of this bug seems null as caller explicitely ignores sendto
error. However this part of code seems to be subject to strange issues
and it may fix them in part. It may be of interest for github issue #1808.
qc_snd_buf() returns an error if sendto has failed. On standard
conditions, we should check for EAGAIN/EWOULDBLOCK errno and if so,
register the file-descriptor in the poller to retry the operation later.
However, quic_conn uses directly the listener fd which is shared for all
QUIC connections of this listener on several threads. Thus, it's
complicated to implement fd supversion via the poller : there is no
mechanism to easily wakeup quic_conn or MUX after a sendto failure.
A quick and simple solution for the moment is to considered a datagram
as properly emitted even on sendto error. In the end, this will trigger
the quic_conn retransmission timer as data will be considered lost on
the network and the send operation will be retried. This solution will
be replaced when fd management for quic_conn is reworked.
In fact, this quick hack was already in use in the current code, albeit
not voluntarily. This is due to a bug caused by an API mismatch on the
return type of qc_snd_buf() which never emits a negative error code
despite its documentation. Thus, all its invocation were considered as a
success. If this bug was fixed, the sending would would have been
interrupted by a break which could cause the transfer to freeze.
qc_snd_buf() invocation is clean up : the break statement is removed.
Send operation is now always explicitely conducted entirely even on
error and buffer data is purged.
A simple optimization has been added to skip over sendto when looping
over several datagrams at the first sendto error. However, to properly
function, it requires a fix on the return type of qc_snd_buf() which is
provided in another patch.
As the behavior before and after this patch seems identical, it is not
labelled as a BUG. However, it should be backported for cleaning
purpose. It may also have an impact on github issue #1808.
The dgram length check in quic_get_dgram_dcid() rejects datagrams
matching exactly the minimum allowed length, which doesn't seem
correct. I doubt any useful packet would be that small but better
fix this to avoid confusing debugging sessions in the future.
This might be backported to 2.6.
This is the same issue as just fixed in b8e0fb97f ("BUG/MINOR: ring/cli:
fix a race condition between the writer and the reader") but this time
for sinks. They're also sucking the ring and present the same race at
high write loads.
This must be backported to 2.2 as well. See comments in the aforementioned
commit for backport hints if needed.
A reference to the sink was added in every forwarder by the commit 2ae25ea24
("MINOR: sink: Add a ref to sink in the sink_forward_target structure"). But
this commit is incomplete. It is not performed for the forwarders created
during a ring parsing.
This patch must be backported to 2.6.
The ring's CLI reader unlocks the read side of a ring and relocks it for
writing only if it needs to re-subscribe. But during this time, the writer
might have pushed data, see nobody subscribed hence woken nobody, while
the reader would have left marking that the applet had no more data. This
results in a dump that will not make any forward progress: the ring is
clogged by this reader which believes there's no data and the writer
will never wake it up.
The right approach consists in verifying after re-attaching if the writer
had made any progress in between, and to report that another call is
needed. Note that a jump back to the beginning would also work but here
we provide better fairness between readers this way.
This needs to be backported to 2.2. The applet API needed to signal the
availability of new data changed a few times since then.
There is a remaining loop in this ugly qc_snd_buf() function which could
lead haproxy to send truncated UDP datagrams. For now on, we send
a complete UDP datagram or nothing!
Must be backported to 2.6.
Implement http-request timeout for QUIC MUX. It is used when the
connection is opened and is triggered if no HTTP request is received in
time. By HTTP request we mean at least a QUIC stream with a full header
section. Then qcs instance is attached to a sedesc and upper layer is
then responsible to wait for the rest of the request.
This timeout is also used when new QUIC streams are opened during the
connection lifetime to wait for full HTTP request on them. As it's
possible to demux multiple streams in parallel with QUIC, each waiting
stream is registered in a list <opening_list> stored in qcc with <start>
as timestamp in qcs for the stream opening. Once a qcs is attached to a
sedesc, it is removed from <opening_list>. When refreshing MUX timeout,
if <opening_list> is not empty, the first waiting stream is used to set
MUX timeout.
This is efficient as streams are stored in the list in their creation
order so CPU usage is minimal. Also, the size of the list is
automatically restricted by flow control limitation so it should not
grow too much.
Streams are insert in <opening_list> by application protocol layer. This
is because only application protocol can differentiate streams for HTTP
messaging from internal usage. A function qcs_wait_http_req() has been
added to register a request stream by app layer. QUIC MUX can then
remove it from the list in qc_attach_sc().
As a side-note, it was necessary to implement attach qcc_app_ops
callback on hq-interop module to be able to insert a stream in waiting
list. Without this, a BUG_ON statement would be triggered when trying to
remove the stream on sedesc attach. This is to ensure that every
requests streams are registered for http-request timeout.
MUX timeout is explicitely refreshed on MAX_STREAM_DATA and STOP_SENDING
frame parsing to schedule http-request timeout if a new stream has been
instantiated. It was already done on STREAM parsing due to a previous
patch.
Try to reorganize qcc_refresh_timeout() to improve its readability. The
main objective is to reduce the indentation level and if sequences by
using goto statement to the end of the function. Also, backend and
frontend code path should be more explicit with this new version.
Refresh the MUX connection timeout in frame parsing functions. This is
necessary as these Rx operation are completed directly from the
quic-conn layer outside of MUX I/O callback. Thus, the timeout should be
refreshed on this occasion.
Note that however on STREAM parsing refresh is only conducted when
receiving the current consecutive data offset.
Timeouts related function have been moved up in the source file to be
able to use them in qcc_decode_qcs().
This commit will be useful for http-request timeout. Indeed, a new
stream may be opened during qcc_decode_qcs() which should trigger this
timeout until a full header section is received and qcs instance is
attached to sedesc.
Store the current step of HTTP message in h3s stream. This reports if we
are in the parsing of headers, content or trailers section. A new enum
h3s_st_req is defined for this.
This field is stored in h3s struct but only used for request stream. It
is left undefined for other streams (control or QPACK streams).
h3_is_frame_valid() has been extended to take into account this state
information. A connection error H3_FRAME_UNEXPECTED is reported if an
invalid frame according to the current state is received; for example a
DATA frame at the beginning of a stream.
