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When an send error is detected on the underlying connection, a pending error is reported to the H2 connection by setting H2_CF_ERR_PENDING flag. When this happen the tail of the mux ring buffer is reset. However some blocking flags remain set and have no chance to be removed later because of the pending error. Especially the flag H2_CF_DEM_MROOM which block data demultiplexing. Thus, it is possible to block a H2 connection with unparsed incoming data. Worse, if a read event is received, it could lead to a wakeup loop between the H2 connection and the underlying SSL connection. The H2 connection is unable to convert the pending error to a fatal error because the demultiplexing is blocked. In the mean time, it tries to receive more data because of the not-consumed read event. On the underlying connection side, the error detected earlier blocks the read, but the H2 connection is woken up to handle the error. To fix the issue, blocking flags must be removed when a send error is caught, H2_CF_MUX_MFULL and H2_CF_DEM_MROOM flags. But, it is not necessary to only release the tail of the mbuf ring. When a send error is detected, all outgoing data can be flushed. So, now, in h2_send(), h2_release_mbuf() function is called on pending error. The mbuf ring is fully released and H2_CF_MUX_MFULL and H2_CF_DEM_MROOM flags are removed. Many thanks to Krzysztof Kozłowski for its help to spot this issue. This patch could be backported at least as far as 2.8. But it is a bit sensitive. So, it is probably a good idea to backport it to 3.2 for now and wait for bug report on older versions.
HAProxy
HAProxy is a free, very fast and reliable reverse-proxy offering high availability, load balancing, and proxying for TCP and HTTP-based applications.
Installation
The INSTALL file describes how to build HAProxy. A list of packages is also available on the wiki.
Getting help
The discourse and the mailing-list are available for questions or configuration assistance. You can also use the slack or IRC channel. Please don't use the issue tracker for these.
The issue tracker is only for bug reports or feature requests.
Documentation
The HAProxy documentation has been split into a number of different files for ease of use. It is available in text format as well as HTML. The wiki is also meant to replace the old architecture guide.
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)
License
HAProxy is licensed under GPL 2 or any later version, the headers under LGPL 2.1. See the LICENSE file for a more detailed explanation.