From 09c716ce117e3c89b4da7ab88f4caaefb43511b5 Mon Sep 17 00:00:00 2001
From: Attila Molnar <attilamolnar@hush.com>
Date: Sat, 13 Feb 2016 19:23:07 +0100
Subject: [PATCH] Limit DNS cache size

---
 include/dns.h | 4 ++++
 src/dns.cpp   | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/include/dns.h b/include/dns.h
index de4bcf422..05df6f69c 100644
--- a/include/dns.h
+++ b/include/dns.h
@@ -302,6 +302,10 @@ class CoreExport DNS : public EventHandler
 	 */
 	static const int MAX_REQUEST_ID = 0xFFFF;
 
+	/** Maximum number of entries in cache
+	 */
+	static const unsigned int MAX_CACHE_SIZE = 1000;
+
 	/**
 	 * Currently cached items
 	 */
diff --git a/src/dns.cpp b/src/dns.cpp
index ff823524c..3d3bc947f 100644
--- a/src/dns.cpp
+++ b/src/dns.cpp
@@ -1060,7 +1060,11 @@ void DNS::HandleEvent(EventType, int)
 					ServerInstance->stats->statsDnsGood++;
 
 				if (!this->GetCache(res.original.c_str()))
+				{
+					if (cache->size() >= MAX_CACHE_SIZE)
+						cache->clear();
 					this->cache->insert(std::make_pair(res.original.c_str(), CachedQuery(res.result, res.type, res.ttl)));
+				}
 
 				Classes[res.id]->OnLookupComplete(res.result, res.ttl, false);
 				delete Classes[res.id];
-- 
2.39.2