HAProxy - Load balancer
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Willy Tarreau 6a4591c3d0 BUG/MEDIUM: connection: report connection errors even when no mux is installed
An annoying issue was met when testing the reverse-http mechanism, by
which failed connection attempts would apparently not be attempted again
when there was no connect timeout. It turned out to be more generalized
than the rhttp system, and actually affects all outgoing connections
relying on NPN or ALPN to choose the mux, on which no mux is installed
and for which the subscriber (ssl_sock) must be notified instead.

The problem appeared during 2.2-dev1 development. First, commit
062df2c23 ("MEDIUM: backend: move the connection finalization step to
back_handle_st_con()") broke the error reporting by testing CO_FL_ERROR
only under CO_FL_CONNECTED. While it still worked OK for cases where a
mux was present, it did not for this specific situation because no
single error path would be considered when no mux was present. Changing
the CO_FL_CONNECTED test to also include CO_FL_ERROR did work, until
a few commits later with 477902bd2 ("MEDIUM: connections: Get ride of
the xprt_done callback.") which removed the xprt_done callback that was
used to indicate success or failure of the transport layer setup, since,
as the commit explains, we can report this via the mux. What this last
commit says is true, except when there is no mux.

For this, however, the sock_conn_iocb() function (formerly conn_fd_handler)
is called for such errors, evaluates a number of conditions, none of which
is matched in this error condition case, since sock_conn_check() instantly
reports an error causing a jump to the leave label. There, the mux is
notified if installed, and the function returns. In other error condition
cases, readiness and activity are checked for both sides, the tasklets
woken up and the corresponding subscriber flags removed. This means that
a sane (and safe) approach would consist in just notifying the subscriber
in case of error, if such a subscriber still exists: if still there, it
means the event hasn't been caught earlier, then it's the right moment
to report it. And since this is done after conn_notify_mux(), it still
leaves all control to the mux once it's installed.

This commit should be progressively backported as far as 2.2 since it's
where the problem was introduced. It's important to clearly check the
error path in each function to make sure the fix still does what it's
supposed to.
2023-11-14 08:49:23 +01:00
.github CI: github: update wolfSSL to 5.6.4 2023-11-03 18:50:45 +01:00
addons MEDIUM: tree-wide: logsrv struct becomes logger 2023-10-13 10:05:06 +02:00
admin MEDIUM: systemd: be more verbose about the reload 2023-10-31 18:59:29 +01:00
dev DEV: sslkeylogger: handle file opening error 2023-10-03 15:23:35 +02:00
doc DOC: quic: Maximum congestion control window configuration 2023-11-13 18:17:43 +01:00
examples EXAMPLES: maintain haproxy 2.8 retrocompatibility for lua mailers script 2023-07-11 16:04:22 +02:00
include MINOR: quic: Maximum congestion control window for each algo 2023-11-13 17:53:18 +01:00
reg-tests REGTESTS: startup: -conf-OK requires -V with current VTest 2023-11-13 14:57:26 +01:00
scripts CI: ssl: add git id support for wolfssl download 2023-10-10 10:34:17 +02:00
src BUG/MEDIUM: connection: report connection errors even when no mux is installed 2023-11-14 08:49:23 +01:00
tests Revert "MAJOR: import: update mt_list to support exponential back-off" 2023-09-15 17:13:43 +02:00
.cirrus.yml CI: cirrus-ci: display gdb bt if any 2023-09-22 08:28:30 +02:00
.gitattributes MINOR: Configure the cpp userdiff driver for *.[ch] in .gitattributes 2021-02-22 18:17:57 +01:00
.gitignore CONTRIB: Add vi file extensions to .gitignore 2023-06-02 18:14:34 +02:00
.mailmap DOC: update Tim's address in .mailmap 2021-09-16 09:14:14 +02:00
.travis.yml CI: travis-ci: temporarily disable arm64 builds 2021-08-07 07:28:15 +02:00
BRANCHES DOC: fix some spelling issues over multiple files 2021-01-08 14:53:47 +01:00
BSDmakefile BUILD: makefile: commit the tiny FreeBSD makefile stub 2023-05-24 17:17:36 +02:00
CHANGELOG [RELEASE] Released version 2.9-dev9 2023-11-04 09:38:16 +01:00
CONTRIBUTING CLEANUP: assorted typo fixes in the code and comments 2021-08-16 12:37:59 +02:00
INSTALL DOC: install: update the wolfSSL required version 2023-11-03 19:02:23 +01:00
LICENSE LICENSE: add licence exception for OpenSSL 2012-09-07 13:52:26 +02:00
MAINTAINERS CLEANUP: assorted typo fixes in the code and comments 2022-11-30 14:02:36 +01:00
Makefile BUILD: ssl: Build with new cryptographic library AWS-LC 2023-09-04 18:19:18 +02:00
README DOC: create a BRANCHES file to explain the life cycle 2019-06-15 22:00:14 +02:00
SUBVERS BUILD: use format tags in VERDATE and SUBVERS files 2013-12-10 11:22:49 +01:00
VERDATE [RELEASE] Released version 2.9-dev9 2023-11-04 09:38:16 +01:00
VERSION [RELEASE] Released version 2.9-dev9 2023-11-04 09:38:16 +01:00

The HAProxy documentation has been split into a number of different files for
ease of use.

Please refer to the following files depending on what you're looking for :

  - INSTALL for instructions on how to build and install HAProxy
  - BRANCHES to understand the project's life cycle and what version to use
  - LICENSE for the project's license
  - CONTRIBUTING for the process to follow to submit contributions

The more detailed documentation is located into the doc/ directory :

  - doc/intro.txt for a quick introduction on HAProxy
  - doc/configuration.txt for the configuration's reference manual
  - doc/lua.txt for the Lua's reference manual
  - doc/SPOE.txt for how to use the SPOE engine
  - doc/network-namespaces.txt for how to use network namespaces under Linux
  - doc/management.txt for the management guide
  - doc/regression-testing.txt for how to use the regression testing suite
  - doc/peers.txt for the peers protocol reference
  - doc/coding-style.txt for how to adopt HAProxy's coding style
  - doc/internals for developer-specific documentation (not all up to date)