package org.klomp.snark.dht;
/*
* From zzzot, modded and relicensed to GPLv2
*/
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import net.i2p.I2PAppContext;
import net.i2p.crypto.SHA1Hash;
import net.i2p.data.DataHelper;
import net.i2p.kademlia.KBucketSet;
import net.i2p.util.Log;
import net.i2p.util.SimpleTimer2;
/**
* All the nodes we know about, stored as a mapping from
* node ID to a Destination and Port.
*
* And a real Kademlia routing table, which stores node IDs only.
*
* @since 0.9.2
* @author zzz
*/
class DHTNodes {
private final I2PAppContext _context;
private long _expireTime;
private final Log _log;
private final ConcurrentHashMap<NID, NodeInfo> _nodeMap;
private final KBucketSet<NID> _kad;
private volatile boolean _isRunning;
/** stagger with other cleaners */
private static final long CLEAN_TIME = 187*1000;
/** how long since last heard from do we delete - BEP 5 says 15 minutes */
private static final long MAX_EXPIRE_TIME = 30*60*1000;
private static final long MIN_EXPIRE_TIME = 10*60*1000;
private static final long DELTA_EXPIRE_TIME = 3*60*1000;
private static final int MAX_PEERS = 799;
/** Buckets older than this are refreshed - BEP 5 says 15 minutes */
private static final long MAX_BUCKET_AGE = 15*60*1000;
private static final int KAD_K = 8;
private static final int KAD_B = 1;
public DHTNodes(I2PAppContext ctx, NID me) {
_context = ctx;
_expireTime = MAX_EXPIRE_TIME;
_log = _context.logManager().getLog(DHTNodes.class);
_nodeMap = new ConcurrentHashMap<NID, NodeInfo>();
_kad = new KBucketSet<NID>(ctx, me, KAD_K, KAD_B, new KBTrimmer(ctx, KAD_K));
}
public void start() {
_isRunning = true;
new Cleaner();
}
public void stop() {
clear();
_isRunning = false;
}
// begin ConcurrentHashMap methods
/**
* @return known nodes, not total net size
*/
public int size() {
return _nodeMap.size();
}
public void clear() {
_kad.clear();
_nodeMap.clear();
}
public NodeInfo get(NID nid) {
return _nodeMap.get(nid);
}
/**
* @return the old value if present, else null
*/
public NodeInfo putIfAbsent(NodeInfo nInfo) {
NodeInfo rv = _nodeMap.putIfAbsent(nInfo.getNID(), nInfo);
// ensure same object in both places
if (rv != null)
_kad.add(rv.getNID());
else
_kad.add(nInfo.getNID());
return rv;
}
public NodeInfo remove(NID nid) {
_kad.remove(nid);
return _nodeMap.remove(nid);
}
public Collection<NodeInfo> values() {
return _nodeMap.values();
}
// end ConcurrentHashMap methods
/**
* DHT
* @param h either a InfoHash or a NID
*/
public List<NodeInfo> findClosest(SHA1Hash h, int numWant) {
NID key;
if (h instanceof NID)
key = (NID) h;
else
key = new NID(h.getData());
List<NID> keys = _kad.getClosest(key, numWant);
List<NodeInfo> rv = new ArrayList<NodeInfo>(keys.size());
for (NID nid : keys) {
NodeInfo ninfo = _nodeMap.get(nid);
if (ninfo != null)
rv.add(ninfo);
}
return rv;
}
/**
* DHT - get random keys to explore
*/
public List<NID> getExploreKeys() {
return _kad.getExploreKeys(MAX_BUCKET_AGE);
}
/**
* Debug info, HTML formatted
* @since 0.9.4
*/
public void renderStatusHTML(StringBuilder buf) {
buf.append(_kad.toString().replace("\n", "<br>\n"));
}
/** */
private class Cleaner extends SimpleTimer2.TimedEvent {
public Cleaner() {
super(SimpleTimer2.getInstance(), 5 * CLEAN_TIME);
}
public void timeReached() {
if (!_isRunning)
return;
long now = _context.clock().now();
int peerCount = 0;
for (Iterator<NodeInfo> iter = DHTNodes.this.values().iterator(); iter.hasNext(); ) {
NodeInfo peer = iter.next();
if (peer.lastSeen() < now - _expireTime) {
iter.remove();
_kad.remove(peer.getNID());
} else {
peerCount++;
}
}
if (peerCount > MAX_PEERS)
_expireTime = Math.max(_expireTime - DELTA_EXPIRE_TIME, MIN_EXPIRE_TIME);
else
_expireTime = Math.min(_expireTime + DELTA_EXPIRE_TIME, MAX_EXPIRE_TIME);
if (_log.shouldLog(Log.DEBUG))
_log.debug("DHT storage cleaner done, now with " +
peerCount + " peers, " +
DataHelper.formatDuration(_expireTime) + " expiration");
schedule(CLEAN_TIME);
}
}
}