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/***************************************************************************
* Copyright (C) 2005 by Joris Guisson *
* joris.guisson@gmail.com *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#ifndef DHTKBUCKET_H
#define DHTKBUCKET_H
#include <qvaluelist.h>
#include <util/constants.h>
#include <ksocketaddress.h>
#include "key.h"
#include "rpccall.h"
#include "task.h"
using bt::Uint32;
using bt::Uint16;
using bt::Uint8;
using KNetwork::KInetSocketAddress;
namespace bt
{
class File;
}
namespace dht
{
class RPCServer;
class KClosestNodesSearch;
class Node;
class Task;
const Uint32 K = 8;
const Uint32 BUCKET_MAGIC_NUMBER = 0xB0C4B0C4;
const Uint32 BUCKET_REFRESH_INTERVAL = 15 * 60 * 1000;
// const Uint32 BUCKET_REFRESH_INTERVAL = 120 * 1000;
struct BucketHeader
{
Uint32 magic;
Uint32 index;
Uint32 num_entries;
};
/**
* @author Joris Guisson
*
* Entry in a KBucket, it basically contains an ip_address of a node,
* the udp port of the node and a node_id.
*/
class KBucketEntry
{
KInetSocketAddress addr;
Key node_id;
bt::TimeStamp last_responded;
Uint32 failed_queries;
Uint32 questionable_pings;
public:
/**
* Constructor, sets everything to 0.
* @return
*/
KBucketEntry();
/**
* Constructor, set the ip, port and key
* @param addr socket address
* @param id ID of node
*/
KBucketEntry(const KInetSocketAddress & addr,const Key & id);
/**
* Copy constructor.
* @param other KBucketEntry to copy
* @return
*/
KBucketEntry(const KBucketEntry & other);
/// Destructor
virtual ~KBucketEntry();
/**
* Assignment operator.
* @param other Node to copy
* @return this KBucketEntry
*/
KBucketEntry & operator = (const KBucketEntry & other);
/// Equality operator
bool operator == (const KBucketEntry & entry) const;
/// Get the socket address of the node
const KInetSocketAddress & getAddress() const {return addr;}
/// Get it's ID
const Key & getID() const {return node_id;}
/// Is this node a good node
bool isGood() const;
/// Is this node questionable (haven't heard from it in the last 15 minutes)
bool isQuestionable() const;
/// Is it a bad node. (Hasn't responded to a query
bool isBad() const;
/// Signal the entry that the peer has responded
void hasResponded();
/// A request timed out
void requestTimeout() {failed_queries++;}
/// The entry has been pinged because it is questionable
void onPingQuestionable() {questionable_pings++;}
/// The null entry
static KBucketEntry null;
};
/**
* @author Joris Guisson
*
* A KBucket is just a list of KBucketEntry objects.
* The list is sorted by time last seen :
* The first element is the least recently seen, the last
* the most recently seen.
*/
class KBucket : public RPCCallListener
{
Q_OBJECT
Uint32 idx;
QValueList<KBucketEntry> entries,pending_entries;
RPCServer* srv;
Node* node;
QMap<RPCCall*,KBucketEntry> pending_entries_busy_pinging;
mutable bt::TimeStamp last_modified;
Task* refresh_task;
public:
KBucket(Uint32 idx,RPCServer* srv,Node* node);
virtual ~KBucket();
/**
* Inserts an entry into the bucket.
* @param entry The entry to insert
*/
void insert(const KBucketEntry & entry);
/// Get the least recently seen node
const KBucketEntry & leastRecentlySeen() const {return entries[0];}
/// Get the number of entries
Uint32 getNumEntries() const {return entries.count();}
/// See if this bucket contains an entry
bool contains(const KBucketEntry & entry) const;
/**
* Find the K closest entries to a key and store them in the KClosestNodesSearch
* object.
* @param kns The object to storre the search results
*/
void findKClosestNodes(KClosestNodesSearch & kns);
/**
* A peer failed to respond
* @param addr Address of the peer
*/
bool onTimeout(const KInetSocketAddress & addr);
/// Check if the bucket needs to be refreshed
bool needsToBeRefreshed() const;
/// save the bucket to a file
void save(bt::File & fptr);
/// Load the bucket from a file
void load(bt::File & fptr,const BucketHeader & hdr);
/// Update the refresh timer of the bucket
void updateRefreshTimer();
/// Set the refresh task
void setRefreshTask(Task* t);
private:
virtual void onResponse(RPCCall* c,MsgBase* rsp);
virtual void onTimeout(RPCCall* c);
void pingQuestionable(const KBucketEntry & replacement_entry);
bool replaceBadEntry(const KBucketEntry & entry);
private slots:
void onFinished(Task* t);
};
}
#endif
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