From 889d521e05f2e922683d48c74eb00290e7a2f548 Mon Sep 17 00:00:00 2001
From: Sadie Powell
Date: Wed, 17 Jul 2024 00:06:50 +0100
Subject: Shuffle the modules about a bit.

---
 modules/hostcycle.cpp | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 modules/hostcycle.cpp

(limited to 'modules/hostcycle.cpp')

diff --git a/modules/hostcycle.cpp b/modules/hostcycle.cpp
new file mode 100644
index 000000000..1b9408a83
--- /dev/null
+++ b/modules/hostcycle.cpp
@@ -0,0 +1,114 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2017-2023 Sadie Powell <sadie@witchery.services>
+ *   Copyright (C) 2013-2015, 2018 Attila Molnar <attilamolnar@hush.com>
+ *
+ * This file is part of InspIRCd.  InspIRCd is free software: you can
+ * redistribute it and/or modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include "inspircd.h"
+#include "clientprotocolevent.h"
+#include "modules/cap.h"
+
+class ModuleHostCycle final
+	: public Module
+{
+	Cap::Reference chghostcap;
+	const std::string quitmsghost;
+	const std::string quitmsguser;
+
+	// Sends a fake quit/join/mode messages for hostame or username cycle.
+	void DoHostCycle(User* user, const std::string& newuser, const std::string& newhost, const std::string& reason)
+	{
+		// The user has the original username/hostname at the time this function is called
+		ClientProtocol::Messages::Quit quitmsg(user, reason);
+		ClientProtocol::Event quitevent(ServerInstance->GetRFCEvents().quit, quitmsg);
+
+		uint64_t silent_id = ServerInstance->Users.NextAlreadySentId();
+		uint64_t seen_id = ServerInstance->Users.NextAlreadySentId();
+
+		User::NeighborList include_chans(user->chans.begin(), user->chans.end());
+		User::NeighborExceptions exceptions;
+
+		FOREACH_MOD(OnBuildNeighborList, (user, include_chans, exceptions));
+
+		// Users shouldn't see themselves quitting when host cycling
+		exceptions.erase(user);
+		for (const auto& [exception, sendto] : exceptions)
+		{
+			LocalUser* u = IS_LOCAL(exception);
+			if ((u) && (!u->quitting) && (!chghostcap.IsEnabled(u)))
+			{
+				if (sendto)
+				{
+					u->already_sent = seen_id;
+					u->Send(quitevent);
+				}
+				else
+				{
+					u->already_sent = silent_id;
+				}
+			}
+		}
+
+		const std::string newfullhost = user->nick + "!" + newuser + "@" + newhost;
+
+		for (auto* memb : include_chans)
+		{
+			Channel* c = memb->chan;
+			ClientProtocol::Events::Join joinevent(memb, newfullhost);
+
+			for (const auto& [chanuser, _] : c->GetUsers())
+			{
+				LocalUser* u = IS_LOCAL(chanuser);
+				if (!u || u == user)
+					continue;
+				if (u->already_sent == silent_id)
+					continue;
+				if (chghostcap.IsEnabled(u))
+					continue;
+
+				if (u->already_sent != seen_id)
+				{
+					u->Send(quitevent);
+					u->already_sent = seen_id;
+				}
+
+				u->Send(joinevent);
+			}
+		}
+	}
+
+public:
+	ModuleHostCycle()
+		: Module(VF_VENDOR, "Sends a fake disconnection and reconnection when a user's username or hostname changes to allow clients to update their internal caches.")
+		, chghostcap(this, "chghost")
+		, quitmsghost("Changing hostname")
+		, quitmsguser("Changing username")
+	{
+	}
+
+	void OnChangeUser(User* user, const std::string& newuser) override
+	{
+		DoHostCycle(user, newuser, user->GetDisplayedHost(), quitmsguser);
+	}
+
+	void OnChangeHost(User* user, const std::string& newhost) override
+	{
+		DoHostCycle(user, user->GetDisplayedUser(), newhost, quitmsghost);
+	}
+};
+
+MODULE_INIT(ModuleHostCycle)
-- 
cgit v1.3.1-10-gc9f91