Multipath TCP (MPTCP), standardized in RFC8684 [1], is a TCP extension
that enables a TCP connection to use different paths.
Multipath TCP has been used for several use cases. On smartphones, MPTCP
enables seamless handovers between cellular and Wi-Fi networks while
preserving Established connections. This use-case is what pushed Apple
to use MPTCP since 2013 in multiple applications [2]. On dual-stack
hosts, Multipath TCP enables the TCP connection to automatically use the
best performing path, either IPv4 or IPv6. If one path fails, MPTCP
automatically uses the other path.
The benefit from MPTCP, both the client and the server have to support
it. Multipath TCP is a backward-compatible TCP extension that is enabled
by default on recent Linux distributions (Debian, Ubuntu, Redhat, ...).
Multipath TCP is included in the Linux kernel since version 5.6 [3].
To use it on Linux, an application must explicitly enable it when
creating the socket. No need to change anything else in the application.
Even if MPTCP is supported by different OS, only Linux supports the
`IPPROTO_MPTCP` protocol, which is why this feature is currently
limited to Linux only.
This patch adds a new parameter 'multipath' to the 'listen' directive
in the HTTP module. This new parameter is only compatible with TCP if
IPPROTO_MPTCP is defined, not with QUIC so far.
Co-authored-by: Maxime Dourov <mux99@live.be>
Link: https://www.rfc-editor.org/rfc/rfc8684.html [1]
Link: https://www.tessares.net/apples-mptcp-story-so-far/ [2]
Link: https://www.mptcp.dev [3]
Line continuation as used in the syntax file might be broken if "compatible"
is set or "C" is added to cpoptions. Fix is to set the "cpoptions" option
to vim default value at script start and restore it later, see
":help use-cpo-save".
Using default highlighting makes it possible to easily overrule
highlighting specified in the syntax file, see ":highlight-default"
in vim help for details.
Instead of highlighting directives in arbitrary positions, proper
parsing of nginx.conf syntax was implemented, matching what nginx does
internally. This allows vim to correctly highlight various complex cases,
including:
return 301 http://example.com/path#fragment";
and also avoids highlighting of parameters as directives, as in
server_name missing.semicolon.example.com
index index.php;
where "index" is not a directive but a parameter of the "server_name"
directive due to missing semicolon.
Most important downside of this approach seems to be that there is no
easy way to introduce directive-specific parameters. As such, only "listen"
directive parameters were preserved.
uwsgi is not a third-party module anymore. 'split_clients' is a new
block directive type. The directives were automatically extracted from
the ngx_command_t arrays, sorted in the C locale and inserted.
Trailing spaces got removed at some places.
I've been maintaining these scripts independently for a while now, even though
I'm no longer active in the community. Seems to me that contrib/ is a good
long-term home for the scripts.
