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UDP GSO on Linux is not implemented in every network devices. For example, this is not available for veth devices frequently used in container environment. In such case, EIO is reported on send() invocation. It is impossible to test at startup for proper GSO support in this case as a listener may be bound on multiple network interfaces. Furthermore, network interfaces may change during haproxy lifetime. As such, the only option is to react on send syscall error when GSO is used. The purpose of this patch is to implement a fallback when encountering such conditions. Emission can be retried immediately by trying to send each prepared datagrams individually. To support this, qc_send_ppkts() is able to iterate over each datagram in a so-called non-GSO fallback mode. Between each emission, a datagram header is rewritten in front of the buffer which allows the sending loop to proceed until last datagram is emitted. To complement this, quic_conn listener is flagged on first GSO send error with value LI_F_UDP_GSO_NOTSUPP. This completely disables GSO for all future emission with QUIC connections using this listener. For the moment, non-GSO fallback mode is activated when EIO is reported after GSO has been set. This is the error reported for the veth usage described above.
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.