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In connect_server(), when a new connection must be instantiated, MUX initialization is delayed if an ALPN setting is present on the server line configuration, as negotiation must be performed to select the correct MUX. However, this is not the case if the ALPN can already be retrieved on the server cache. This check is performed too late however and may cause issue with the QUIC stack. The problem can happen when the server ALPN is not yet set. In the normal case, quic_conn layer is instantiated and MUX init is delayed until the handshake completion. When the MUX is finally instantiated, it reused without any issue app_ops from its quic_conn, which is derived from the negotiated ALPN. However, there is a race condition if another QUIC connection populates the server ALPN cache. If this happens after the first quic_conn init but prior to the MUX delay check, the MUX will thus immediately start in connect_server(). When app_ops is retrieved from its quic_conn, a crash occurs in qcc_install_app_ops() as the QUIC handshake is not yet finalized : #0 0x000055e242a66df4 in qcc_install_app_ops (qcc=0x7f127c39da90, app_ops=0x0) at src/mux_quic.c:1697 1697 if (app_ops->init && !app_ops->init(qcc)) { [Current thread is 1 (Thread 0x7f12810f06c0 (LWP 25758))] To fix this, MUX delay check is moved up in connect_server(). It is now performed prior conn_prepare() which is responsible for the quic_conn layer instantiation. Thus, it ensures consistency for the QUIC stack : MUX init is always delayed if the quic_conn does not reuses itself the SSL session and ALPN server cache (no quic_reuse_srv_params()). This must be backported up to 3.3.
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.