Changeset 1265

Timestamp:

10/05/08 11:49:53 (2 years ago)

Author:

ahu

Message:

reported by Andreas Jakum & investigated by Stefan Schmidt - make sure we don't hammer parent zones in case of failed delegations to servers that don't exist at all. Only invalidate once every 10 seconds

Location:

trunk/pdns/pdns

Files:

• recursor_cache.cc (modified) (2 diffs)
• recursor_cache.hh (modified) (1 diff)
• syncres.cc (modified) (1 diff)

trunk/pdns/pdns/recursor_cache.cc

@@ -234 +234 @@
 
     //    cerr<<"time left : "<<ttd - now<<", "<< (res ? res->size() : 0) <<"\n";
-    return (unsigned int)ttd-now;
+    return (int)ttd-now;
   }
   return -1;
@@ -363 +363 @@
 }
 
+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()) 
+    return false;
+
+  int32_t ttl = iter->getTTD() - now;
+  if(ttl < 0) 
+    return false;  // would be dead anyhow
+
+  if(ttl > newTTL) {
+    d_cachecachevalid=false;
+
+    ttl = newTTL;
+    uint32_t newTTD = now + ttl;
+    
+    CacheEntry ce = *iter;
+    for(vector<StoredRecord>::iterator j = ce.d_records.begin() ; j != ce.d_records.end(); ++j)  {
+      j->d_ttd = newTTD;
+    }
+    
+    d_cache.replace(iter, ce);
+    return true;
+  }
+  return false;
+}
+
+
 void MemRecursorCache::doDumpAndClose(int fd)
 {

trunk/pdns/pdns/recursor_cache.hh

@@ -40 +40 @@
   void doDumpAndClose(int fd);
   int doWipeCache(const string& name, uint16_t qtype=0xffff);
+  bool doAgeCache(time_t now, const string& name, uint16_t qtype, int32_t newTTL);
   uint64_t cacheHits, cacheMisses;
   bool d_followRFC2181;

trunk/pdns/pdns/syncres.cc

@@ -608 +608 @@
         LOG<<prefix<<qname<<": Failed to resolve via any of the "<<(unsigned int)rnameservers.size()<<" offered NS at level '"<<auth<<"'"<<endl;
         if(auth!="." && flawedNSSet) {
-          g_stats.nsSetInvalidations++;
-          LOG<<prefix<<qname<<": Invalidating nameservers for level '"<<auth<<"', next query might succeed"<<endl;
-          RC.doWipeCache(auth, QType::NS);
+          LOG<<prefix<<qname<<": Ageing nameservers for level '"<<auth<<"', next query might succeed"<<endl;
+          if(RC.doAgeCache(d_now.tv_sec, auth, QType::NS, 10))
+            g_stats.nsSetInvalidations++;
         }
         return -1;