*) make DHT DoS check configurable (requested by KoH)

- check can be disabled via property indexDistribution.dhtReceiptLimitEnabled
   - upper bound can be configured via indexDistribution.dhtReceiptLimit

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@2234 6c8d7289-2bf4-0310-a012-ef5d649a1542

htroot/yacy/transferRWI.java

@@ -78,6 +78,8 @@ public final class transferRWI {
         final int entryc      = Integer.parseInt(post.get("entryc", "")); // number of entries in indexes
         byte[] indexes        = post.get("indexes", "").getBytes();       // the indexes, as list of word entries
         boolean granted       = sb.getConfig("allowReceiveIndex", "false").equals("true");
+        boolean checkLimit    = sb.getConfigBool("indexDistribution.dhtReceiptLimitEnabled", true);
+        final long cachelimit = sb.getConfigLong("indexDistribution.dhtReceiptLimit", 1000);
         final yacySeed otherPeer = yacyCore.seedDB.get(iam);
         final String otherPeerName = iam + ":" + ((otherPeer == null) ? "NULL" : (otherPeer.getName() + "/" + otherPeer.getVersion()));                
         
@@ -91,7 +93,7 @@ public final class transferRWI {
             sb.getLog().logInfo("Rejecting RWIs from peer " + otherPeerName + ". Not granted.");
             result = "not_granted";
             pause = 0;
-        } else if (sb.wordIndex.kSize() > 1000) {
+        } else if (checkLimit && sb.wordIndex.kSize() > cachelimit) {
             // we are too busy to receive indexes
             sb.getLog().logInfo("Rejecting RWIs from peer " + otherPeerName + ". We are too busy (buffersize=" + sb.wordIndex.kSize() + ").");
             granted = false; // don't accept more words if there are too many words to flush
@@ -171,7 +173,10 @@ public final class transferRWI {
                 sb.getLog().logInfo("Received " + received + " Words [" + wordhashes[0] + " .. " + wordhashes[received - 1] + "]/" + avdist + " from " + otherPeerName + ", processed in " + (System.currentTimeMillis() - startProcess) + " milliseconds, requesting " + unknownURL.size() + " URLs");
             }
             result = "ok";
-            pause = (sb.wordIndex.kSize() < 500) ? 0 : 60 * sb.wordIndex.kSize(); // estimation of necessary pause time
+            
+            if (checkLimit) {
+                pause = (sb.wordIndex.kSize() < 500) ? 0 : 60 * sb.wordIndex.kSize(); // estimation of necessary pause time
+            }
         }
 
         prop.put("unknownURL", unknownURLs.toString());

source/de/anomic/plasma/plasmaDHTTransfer.java

@@ -258,13 +258,14 @@ public class plasmaDHTTransfer extends Thread {
         if (transferRWIResult != null && transferRWIResult.containsKey("pause")) {
             String pauseStr = (String) transferRWIResult.get("pause");
             try { pause = Integer.valueOf(pauseStr).intValue(); } catch (NumberFormatException numEx){}
-            if (pause <= 0) pause = 60000;
+            if (pause < 0) pause = 60000;
             else if (pause > 1800000) pause = 1800000;
         }        
         return pause;     
     }
     
     private void pause(long sleepTime) throws InterruptedException {        
+        if (sleepTime == 0) return;
         long sleepCounter = sleepTime / 1000;
         long sleepRest = sleepTime % 1000;
         while (!this.isAborted() && sleepCounter > 0) {

yacy.init

@@ -649,6 +649,14 @@ indexDistribution.minChunkSize = 5
 indexDistribution.maxChunkSize = 1000
 indexDistribution.startChunkSize = 50
 
+# defines if the peer should reject incoming index transfer
+# request if a given limit is reached
+indexDistribution.dhtReceiptLimitEnabled = false
+
+# defines the word cache for DHT reaches this level
+# the peer reports itself as busy
+indexDistribution.dhtReceiptLimit = 1000
+
 # Distribution of Citation-Reference (CR-) files
 # The distribution is done in two steps:
 # first step to anonymize the records