* ClientPeerSelector: Implement strict ordering of peers,

based on XOR distance from a random hash
      separately generated for each tunnel pool

history.txt

@@ -1,3 +1,8 @@
+2008-03-08 zzz
+    * ClientPeerSelector: Implement strict ordering of peers,
+      based on XOR distance from a random hash
+      separately generated for each tunnel pool
+
 2008-03-07 zzz
     * Naming: Optimize lookups for a destkey
     * ProfileOrganizer, TunnelPoolSettings, ClientPeerSelector:

router/java/src/net/i2p/router/RouterVersion.java

@@ -17,7 +17,7 @@ import net.i2p.CoreVersion;
 public class RouterVersion {
     public final static String ID = "$Revision: 1.548 $ $Date: 2008-02-10 15:00:00 $";
     public final static String VERSION = "0.6.1.31";
-    public final static long BUILD = 3203;
+    public final static long BUILD = 3204;
     public static void main(String args[]) {
         System.out.println("I2P Router version: " + VERSION + "-" + BUILD);
         System.out.println("Router ID: " + RouterVersion.ID);

router/java/src/net/i2p/router/networkdb/kademlia/PeerSelector.java

@@ -25,7 +25,7 @@ import net.i2p.stat.Rate;
 import net.i2p.stat.RateStat;
 import net.i2p.util.Log;
 
-class PeerSelector {
+public class PeerSelector {
     protected Log _log;
     protected RouterContext _context;
     
@@ -180,7 +180,7 @@ class PeerSelector {
             peerHashes.removeAll(failing);
     }
     
-    protected BigInteger getDistance(Hash targetKey, Hash routerInQuestion) {
+    public static BigInteger getDistance(Hash targetKey, Hash routerInQuestion) {
         // plain XOR of the key and router
         byte diff[] = DataHelper.xor(routerInQuestion.getData(), targetKey.getData());
         return new BigInteger(1, diff);

router/java/src/net/i2p/router/tunnel/pool/ClientPeerSelector.java

@@ -28,8 +28,8 @@ class ClientPeerSelector extends TunnelPeerSelector {
         
         matches.remove(ctx.routerHash());
         ArrayList rv = new ArrayList(matches);
-        // Todo - Rather than shuffle, sort using xor distance from settings.getRandomKey()
+        if (rv.size() > 1)
-        Collections.shuffle(rv, ctx.random());
+            orderPeers(rv, settings.getRandomKey());
         if (settings.isInbound())
             rv.add(0, ctx.routerHash());
         else

router/java/src/net/i2p/router/tunnel/pool/ExploratoryPeerSelector.java

@@ -43,7 +43,8 @@ class ExploratoryPeerSelector extends TunnelPeerSelector {
         
         matches.remove(ctx.routerHash());
         ArrayList rv = new ArrayList(matches);
-        Collections.shuffle(rv, ctx.random());
+        if (rv.size() > 1)
+            orderPeers(rv, settings.getRandomKey());
         if (settings.isInbound())
             rv.add(0, ctx.routerHash());
         else

router/java/src/net/i2p/router/tunnel/pool/TunnelPeerSelector.java

@@ -1,12 +1,14 @@
 package net.i2p.router.tunnel.pool;
 
 import java.util.*;
+import java.math.BigInteger;
 import net.i2p.I2PAppContext;
 import net.i2p.data.*;
 import net.i2p.router.Router;
 import net.i2p.router.RouterContext;
 import net.i2p.router.TunnelPoolSettings;
 import net.i2p.router.networkdb.kademlia.FloodfillNetworkDatabaseFacade;
+import net.i2p.router.networkdb.kademlia.PeerSelector;
 import net.i2p.router.peermanager.PeerProfile;
 import net.i2p.util.Log;
 
@@ -449,4 +451,21 @@ public abstract class TunnelPeerSelector {
         //System.err.println("Filter unreachable? " + rv + " (inbound? " + isInbound + ", exploratory? " + isExploratory);
         return rv;
     }
+
+    protected void orderPeers(List rv, Hash hash) {
+            Collections.sort(rv, new HashComparator(hash));
+    }
+
+    private class HashComparator implements Comparator {
+        private Hash _hash;
+
+        private HashComparator(Hash h) {
+            _hash = h;
+        }
+        public int compare(Object l, Object r) {
+            BigInteger ll = PeerSelector.getDistance(_hash, (Hash) l);
+            BigInteger rr = PeerSelector.getDistance(_hash, (Hash) r);
+            return ll.compareTo(rr);
+        }
+    }
 }