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| author | Rodrigo Arias Mallo <rodarima@gmail.com> | 2024-12-30 18:25:19 +0100 |
|---|---|---|
| committer | Rodrigo Arias Mallo <rodarima@gmail.com> | 2024-12-30 18:25:19 +0100 |
| commit | d77b21e374a6745e9bfb92ebfcb150b905b54c6e (patch) | |
| tree | 95074312ec1988ddbd9612678b9e3c28576a0a85 /rfc | |
| parent | aad65628cb4eb6739ad0d110e78a00e5d2cd172c (diff) | |
Add RFC 003: UNIX sockets in ULRs
Diffstat (limited to 'rfc')
| -rw-r--r-- | rfc/003-unix-sockets/index.html | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/rfc/003-unix-sockets/index.html b/rfc/003-unix-sockets/index.html new file mode 100644 index 0000000..17119d6 --- /dev/null +++ b/rfc/003-unix-sockets/index.html @@ -0,0 +1,125 @@ +<!doctype html> +<html> +<head> + <title>Dillo RFC 003 - UNIX sockets in URLs</title> +<style> +body { + background: white; + line-height: 1.5; + margin: 3em; + font-family: sans-serif; + max-width: 72ch; +} +h1 { margin-bottom: 1em; } +header { border: solid 1px #ddd; background: #f5f5f5; padding: 0.25em 1em } +dt { font-weight: bold } +dd { margin-left: 2ch; } +pre { padding-left: 4ch; } +</style> +</head> +<body> + +<h1>Dillo RFC 003 - UNIX sockets in URLs</h1> + +<header> +<dl> +<dt>State</dt><dd>Draft</dd> +<dt>Date</dt><dd>Draft on 2024-12-30</dd> +<dt>Author</dt><dd>Rodrigo Arias Mallo + <<a href="mailto:rodarima@gmail.com">rodarima@gmail.com</a>></dd> +</dl> +</header> + +<h2>Abstract</h2> + +<p>This document adds UNIX sockets support to URLs by using host names with the TLD +“.unix” and a unix.hosts file that describe where in the file system +the socket file is located for a given host.</p> + +<h2>Proposal</h2> + +<p>UNIX sockets allow permissions to be established on a socket so that only a user +or a group of users can connect to it. However, the HTTP protocol doesn’t make +provisions to specify how to connect to UNIX sockets, and instead it uses TCP +to connect to a given host, which is resolved via DNS to an IP address.</p> + +<p>To allow connecting to UNIX sockets, we propose using a special top level +domain (TLD) “.unix” which can be mapped to a local UNIX socket. In +this way, an URL like the following:</p> + +<pre><code>http://example.unix/index.html +</code></pre> + +<p>Will search for a socket file mapped to “example.unix” and +perform a HTTP query over that socket to retrieve the “/index.html” +file. Similarly, other protocols like Gopher or Gemini can work with UNIX +sockets in the same way.</p> + +<p>This scheme allows a user to place the sockets in any path of their choosing, +which doesn’t need to be revealed in the URL.</p> + +<p>To support this scheme, a unix.hosts file is be used with a similar syntax as +the hosts file, in such a way that a user can define its own aliases:</p> + +<pre><code>unix:~/.dillo/example.sock example.unix +</code></pre> + +<p>Similarly, a system-wide configuration could be made available, and still +inherit the benefits from UNIX permissions:</p> + +<pre><code>unix:/var/lib/foobar.sock foobar.unix +</code></pre> + +<p>This proposal fails gracefully when a URL referring to a UNIX socket is +opened by a program that doesn’t support UNIX hosts, as the top level +domain “.unix” doesn’t exist +[<a href="https://data.iana.org/TLD/tlds-alpha-by-domain.txt">1</a>]. +Additionally, a program may determine that a host ending with .unix will use a +UNIX connection, so it is not needed to query any DNS server.</p> + +<p>If no entry is found on the unix.hosts file for a given .unix host a default +set of locations for the UNIX socket could be attempted, but this is left out of +the current proposal.</p> + +<h2>Implementation details</h2> + +<p>This proposal could be implemented by any program that performs network +operations, it is not specific to Dillo. The following sections apply only to +Dillo itself, but may serve as a reference to other implementations.</p> + +<h3>The unix.hosts file</h3> + +<p>The format of the hosts file extends the syntax of /etc/hosts to allow hosts +that begin with the “unix:” prefix and are followed by a path. The +rest of the line defines aliases to that socket separated by white-spaces.</p> + +<pre><code>unix:/var/lib/foobar.sock foobar.unix +</code></pre> + +<p>The symbol ~ is expanded by the value of the <code>$HOME</code> variable of +the user performing the lookup. Therefore, to define sockets in the user home +directory:</p> + +<pre><code>unix:~/foobar.sock foobar.unix foo-bar.unix +</code></pre> + +<h3>UNIX host resolution</h3> + +<p>The process to resolve a UNIX host is quite simple. First, determine if the +URL host name ends in “.unix”. If so, follow the steps below. +Otherwise, proceed with the current host resolution, possibly querying DNS +servers.</p> + +<p>To find how to connect to a .unix host, identify a matching entry in the +hosts.unix file by looking at all the aliases for each UNIX socket. If there is +a match, use the unix socket patch of that line and the socket() interface with +the <code>AF_UNIX</code> family.</p> + +<h3>Multiple entries</h3> + +<p>In order to give users the ability to redefine aliases to their own UNIX +sockets, the entries in the unix.hosts file have precedence over the ones in the +system-wide unix.hosts configuration file.</p> + +</body> +</html> |