doAgeCache.patch

Index: pdns/recursor_cache.cc
===================================================================
--- pdns/recursor_cache.cc	(Revision 2495)
+++ pdns/recursor_cache.cc	(Arbeitskopie)
@@ -299,22 +299,34 @@
 bool MemRecursorCache::doAgeCache(time_t now, const string& name, uint16_t qtype, int32_t newTTL)
 {
   cache_t::iterator iter = d_cache.find(tie(name, qtype));
-  if(iter == d_cache.end()) 
+  uint32_t maxTTD=std::numeric_limits<uint32_t>::min();
+  if(iter == d_cache.end()) {
     return false;
+  }
 
-  int32_t ttl = iter->getTTD() - now;
-  if(ttl < 0) 
+  CacheEntry ce = *iter;
+
+  if(ce.d_records.size()==1) {
+    maxTTD=ce.d_records.begin()->d_ttd;
+  }
+  else { // find the LATEST ttd
+    for(vector<StoredRecord>::const_iterator i=ce.d_records.begin(); i != ce.d_records.end(); ++i)
+      maxTTD=max(maxTTD, i->d_ttd);
+  }
+
+  int32_t maxTTL = maxTTD - now;
+
+  if(maxTTL < 0)
     return false;  // would be dead anyhow
 
-  if(ttl > newTTL) {
+  if(maxTTL > newTTL) {
     d_cachecachevalid=false;
 
-    ttl = newTTL;
-    uint32_t newTTD = now + ttl;
+    uint32_t newTTD = now + newTTL;
     
-    CacheEntry ce = *iter;
     for(vector<StoredRecord>::iterator j = ce.d_records.begin() ; j != ce.d_records.end(); ++j)  {
-      j->d_ttd = newTTD;
+      if(j->d_ttd>newTTD) // do never renew expired or older TTLs
+        j->d_ttd = newTTD;
     }
     
     d_cache.replace(iter, ce);