[PATCH] Documented the http2 directive

[Maxim Dounin]

Hello!

On Tue, Jun 13, 2023 at 02:56:50PM +0100, Yaroslav Zhuravlev wrote:

> @@ -55,7 +55,9 @@
>  <para>
>  <example>
>  server {
> -    listen 443 ssl http2;
> +    listen 443 ssl;
> +
> +    http2 on;
>  
>      ssl_certificate server.crt;
>      ssl_certificate_key server.key;
> @@ -82,6 +84,22 @@
>  
>  <section id="directives" name="Directives">
>  
> +<directive name="http2">
> +<syntax><literal>on</literal> | <literal>off</literal></syntax>
> +<default>off</default>
> +<context>http</context>
> +<context>server</context>
> +<appeared-in>1.25.1</appeared-in>
> +
> +<para>
> +Enables
> +the <link url="https://datatracker.ietf.org/doc/html/rfc9113">HTTP/2</link>
> +protocol.
> +</para>

This probably needs some more details.

In particular:

- For SNI-based virtual servers, this only fully works with 
  OpenSSL 1.0.2h and up.  For older OpenSSL versions (1.0.2 - 1.0.2g), 
  HTTP/2 needs to be enabled in the default virtual server as well.

- For non-SSL listening sockets, HTTP/2 needs to be enabled in
  the default virtual server as well.

Do not insist on adding it right now though, a separate patch 
clarifying the details should be good enough.

[...]

-- 
Maxim Dounin
http://mdounin.ru/