From eef45dbfb90f951f3048038aea3ff68b5c157f6d Mon Sep 17 00:00:00 2001
From: Attila Molnar
Date: Fri, 2 Sep 2016 19:22:50 +0200
Subject: m_spanningtree Refuse topic changes that would result in desync

This is a workaround until the protocol is updated
---
 src/modules/m_spanningtree/main.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'src/modules/m_spanningtree/main.cpp')

diff --git a/src/modules/m_spanningtree/main.cpp b/src/modules/m_spanningtree/main.cpp
index 56cc78cd2..6bf9e8044 100644
--- a/src/modules/m_spanningtree/main.cpp
+++ b/src/modules/m_spanningtree/main.cpp
@@ -365,6 +365,18 @@ void ModuleSpanningTree::OnUserInvite(User* source, User* dest, Channel* channel
 	}
 }
 
+ModResult ModuleSpanningTree::OnPreTopicChange(User* user, Channel* chan, const std::string& topic)
+{
+	// XXX: Deny topic changes if the current topic set time is the current time or is in the future because
+	// other servers will drop our FTOPIC. This restriction will be removed when the protocol is updated.
+	if ((chan->topicset >= ServerInstance->Time()) && (Utils->serverlist.size() > 1))
+	{
+		user->WriteNumeric(ERR_CHANOPRIVSNEEDED, chan->name, "Retry topic change later");
+		return MOD_RES_DENY;
+	}
+	return MOD_RES_PASSTHRU;
+}
+
 void ModuleSpanningTree::OnPostTopicChange(User* user, Channel* chan, const std::string &topic)
 {
 	// Drop remote events on the floor.
@@ -762,6 +774,7 @@ Version ModuleSpanningTree::GetVersion()
 void ModuleSpanningTree::Prioritize()
 {
 	ServerInstance->Modules->SetPriority(this, PRIORITY_LAST);
+	ServerInstance->Modules.SetPriority(this, I_OnPreTopicChange, PRIORITY_FIRST);
 }
 
 MODULE_INIT(ModuleSpanningTree)
-- 
cgit v1.3.1-10-gc9f91