From 3f008343a4dcd51c29e53c71eee835e64cf53145 Mon Sep 17 00:00:00 2001
From: Jan Willamowius <jan@willamowius.de>
Date: Sat, 23 Mar 2019 14:54:23 +0100
Subject: [PATCH] fix for LCF caching

---
 RasTbl.cxx                 | 11 +++++++++++
 RasTbl.h                   |  1 +
 docs/manual/neighbors.sgml |  5 +++++
 gk.cxx                     |  1 +
 4 files changed, 18 insertions(+)

diff --git a/RasTbl.cxx b/RasTbl.cxx
index b24c5c6e..eba36392 100644
--- a/RasTbl.cxx
+++ b/RasTbl.cxx
@@ -5954,6 +5954,7 @@ PreliminaryCall * PreliminaryCallTable::Find(const H225_CallIdentifier & id) con
 CallLoopTable::CallLoopTable() : Singleton<CallLoopTable>("CallLoopTable")
 {
     m_expireTime = GkConfig()->GetInteger("RasSrv::LRQFeatures", "LoopDetectionExpireTime", 60);
+    m_reprocessLCFs = GkConfig()->GetInteger("RasSrv::LRQFeatures", "LoopDetectionReprocessLCFs", false);
 }
 
 CallLoopTable::~CallLoopTable()
@@ -5980,6 +5981,16 @@ CallLoopTable::LoopResult CallLoopTable::IsLoop(const H225_LocationRequest & lrq
             return NoLoop;
         }
         if ((*iter).second.m_cachedLCF) {
+            if (m_reprocessLCFs) {
+                // reprocess all LCFs if switch is set
+                return NoLoop;
+            }
+            if (AsDotString((*iter).second.m_cachedLCF->m_rasAddress, false) == from
+                || AsDotString((*iter).second.m_cachedLCF->m_callSignalAddress, false) == from) {
+                // don't use a cached LCF if it points back to the sender
+                // must be a cached version for sender further down the stream
+                return NoLoop;
+            }
             cachedLCF = *(*iter).second.m_cachedLCF;
             return CachedLCF;
         }
diff --git a/RasTbl.h b/RasTbl.h
index 50b51a88..bca742e5 100644
--- a/RasTbl.h
+++ b/RasTbl.h
@@ -2347,6 +2347,7 @@ class CallLoopTable : public Singleton<CallLoopTable>
 	mutable PReadWriteMutex tableLock;
     std::map<PString, RequestData> m_knownCalls;
     unsigned m_expireTime;
+    bool m_reprocessLCFs;
 };
 
 #endif // RASTBL_H
diff --git a/docs/manual/neighbors.sgml b/docs/manual/neighbors.sgml
index 76040d02..cedfb093 100644
--- a/docs/manual/neighbors.sgml
+++ b/docs/manual/neighbors.sgml
@@ -195,6 +195,11 @@ Default: <tt>60</tt><newline>
 <p>
 Time duration in seconds how long to store data about calls GnuGk has seen.
 
+<item><tt/LoopDetectionReprocessLCFs=1/<newline>
+Default: <tt>0</tt><newline>
+<p>
+Don't cache any LCFs in the loop detection. Use if cached LCFs with incorrect data (for another endpoint) break the routing.
+
 </itemize>
 
 
diff --git a/gk.cxx b/gk.cxx
index 1d1bf33b..af77ed96 100644
--- a/gk.cxx
+++ b/gk.cxx
@@ -533,6 +533,7 @@ const char * KnownConfigEntries[][2] = {
 	{ "RasSrv::LRQFeatures", "ForwardResponse" },
 	{ "RasSrv::LRQFeatures", "LoopDetection" },
 	{ "RasSrv::LRQFeatures", "LoopDetectionExpireTime" },
+	{ "RasSrv::LRQFeatures", "LoopDetectionReprocessLCFs" },
 	{ "RasSrv::LRQFeatures", "LRQPingInterval" },
 	{ "RasSrv::LRQFeatures", "NeighborTimeout" },
 	{ "RasSrv::LRQFeatures", "PingAlias" },