From 8e461051cdeaa83dcdc749f520c93ad763886da9 Mon Sep 17 00:00:00 2001
From: Les De Ridder <les@lesderid.net>
Date: Mon, 16 Nov 2020 01:11:23 +0100
Subject: [PATCH] Add basic PROXY (version 1) debug support

---
 README.md                | 12 ++++++++----
 source/ircd/connection.d | 19 ++++++++++++++++---
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 14b4e99..74fae54 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ salty-ircd is an [Internet Relay Chat](https://en.wikipedia.org/wiki/Internet_Re
 The main goals of salty-ircd are strict RFC compliance and security.
 
 ### RFC compliance
-salty-ircd aims to be fully compliant with the IRC RFCs (in 'RFC mode'), specifically [RFC 1459](https://tools.ietf.org/html/rfc1459), [RFC 2811](https://tools.ietf.org/html/rfc2811), [RFC 2812](https://tools.ietf.org/html/rfc2812), and [RFC 2813](https://tools.ietf.org/html/rfc2813) (planned), including all errata.
+salty-ircd aims to be fully compliant with the IRC RFCs (by default), specifically [RFC 1459](https://tools.ietf.org/html/rfc1459), [RFC 2811](https://tools.ietf.org/html/rfc2811), [RFC 2812](https://tools.ietf.org/html/rfc2812), and [RFC 2813](https://tools.ietf.org/html/rfc2813) (planned), including all errata.
 Newer RFCs take precedence over older RFCs.
 
 Any additional features breaking RFC compliance are available through compile-time options.
@@ -25,9 +25,13 @@ Build dependencies:
 
 Build command:
 * RFC compliant: `dub build`
-* With all additional features: `dub build -c=modern`
+* Modern (all additional features): `dub build -c=modern`
 
-TODO: Add a way to supply a custom list of compile-time options.
+The 'modern' configuration aims to be mostly compatible with UnrealIRCd user modes/chars.
+
+When `-d=ProxyV1` is added to the build command, salty-ircd can accept traffic through the PROXY protocol (version 1), e.g. from an UnrealIRCd server running with [a custom module](https://github.com/lesderid/unrealircd5_proxyv1_copy). Please see this module's readme for more information. Note that this is simply a development/debugging option and should not be used for a production server.
+
+TODO: Add a method to supply a custom list of compile-time options.
 
 ## Running
 First, create the configuration file, `config.sdl`. You can find a template in `config.template.sdl`.
@@ -35,4 +39,4 @@ First, create the configuration file, `config.sdl`. You can find a template in `
 Then, simply run `./out/salty-ircd`.
 
 ## License
-The source code for salty-ircd is licensed under the [University of Illinois/NCSA Open Source License](LICENSE).
+[University of Illinois/NCSA Open Source License](LICENSE).
diff --git a/source/ircd/connection.d b/source/ircd/connection.d
index 0462bd1..e80cf61 100644
--- a/source/ircd/connection.d
+++ b/source/ircd/connection.d
@@ -42,6 +42,9 @@ class Connection
 
     string pass = null;
 
+    debug (ProxyV1)
+    bool proxy;
+
     @property auto channels()
     {
         return _server.channels.filter!(c => c.members.canFind(this));
@@ -183,6 +186,13 @@ class Connection
                 continue;
             }
 
+            debug (ProxyV1)
+            if (message.command == "PROXY")
+            {
+                proxy = true;
+                hostname = getHost(message.parameters[1]);
+            }
+
             //NOTE: The RFCs don't specify whether commands are case-sensitive
             version (BasicFixes)
             {
@@ -367,7 +377,8 @@ class Connection
         user = message.parameters[0];
         modes = modeMaskToModes(message.parameters[1]);
         realname = message.parameters[3];
-        hostname = getHost();
+        debug (ProxyV1) {}
+        else hostname = getHost();
 
         if (!wasRegistered && registered)
         {
@@ -1381,9 +1392,11 @@ class Connection
         closeConnection();
     }
 
-    string getHost()
+    string getHost(string addressString = null)
     {
-        auto address = parseAddress(_connection.remoteAddress.toAddressString);
+        auto address = parseAddress(addressString != null ?
+                                    addressString :
+                                    _connection.remoteAddress.toAddressString);
         auto hostname = address.toHostNameString;
         if (hostname is null)
         {