aria2/src/DHTBucket.cc

286 lines
8.3 KiB
C++

/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* 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
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "DHTBucket.h"
#include <cstring>
#include <cassert>
#include <algorithm>
#include "DHTNode.h"
#include "LogFactory.h"
#include "Logger.h"
#include "util.h"
#include "DHTConstants.h"
#include "a2functional.h"
#include "bittorrent_helper.h"
#include "bitfield.h"
#include "wallclock.h"
#include "fmt.h"
namespace aria2 {
DHTBucket::DHTBucket
(size_t prefixLength,
const unsigned char* max, const unsigned char* min,
const SharedHandle<DHTNode>& localNode)
: prefixLength_(prefixLength),
localNode_(localNode),
lastUpdated_(global::wallclock)
{
memcpy(max_, max, DHT_ID_LENGTH);
memcpy(min_, min, DHT_ID_LENGTH);
}
DHTBucket::DHTBucket(const SharedHandle<DHTNode>& localNode)
: prefixLength_(0),
localNode_(localNode),
lastUpdated_(global::wallclock)
{
memset(max_, 0xffu, DHT_ID_LENGTH);
memset(min_, 0, DHT_ID_LENGTH);
}
DHTBucket::~DHTBucket() {}
void DHTBucket::getRandomNodeID(unsigned char* nodeID) const
{
if(prefixLength_ == 0) {
util::generateRandomKey(nodeID);
} else {
size_t lastByteIndex = (prefixLength_-1)/8;
util::generateRandomKey(nodeID);
memcpy(nodeID, min_, lastByteIndex+1);
}
}
bool DHTBucket::isInRange(const SharedHandle<DHTNode>& node) const
{
return isInRange(node->getID(), max_, min_);
}
bool DHTBucket::isInRange(const unsigned char* nodeID) const
{
return isInRange(nodeID, max_, min_);
}
// Returns true if nodeID is in [min, max] (inclusive).
bool DHTBucket::isInRange(const unsigned char* nodeID,
const unsigned char* max,
const unsigned char* min) const
{
return
!std::lexicographical_compare(&nodeID[0], &nodeID[DHT_ID_LENGTH],
&min[0], &min[DHT_ID_LENGTH]) &&
!std::lexicographical_compare(&max[0], &max[DHT_ID_LENGTH],
&nodeID[0], &nodeID[DHT_ID_LENGTH]);
}
bool DHTBucket::addNode(const SharedHandle<DHTNode>& node)
{
notifyUpdate();
std::deque<SharedHandle<DHTNode> >::iterator itr =
std::find_if(nodes_.begin(), nodes_.end(), derefEqual(node));
if(itr == nodes_.end()) {
if(nodes_.size() < K) {
nodes_.push_back(node);
return true;
} else {
if(nodes_.front()->isBad()) {
nodes_.erase(nodes_.begin());
nodes_.push_back(node);
return true;
} else {
return false;
}
}
} else {
nodes_.erase(itr);
nodes_.push_back(node);
return true;
}
}
void DHTBucket::cacheNode(const SharedHandle<DHTNode>& node)
{
// cachedNodes_ are sorted by last time seen
cachedNodes_.push_front(node);
if(cachedNodes_.size() > CACHE_SIZE) {
cachedNodes_.resize(CACHE_SIZE, SharedHandle<DHTNode>());
}
}
void DHTBucket::dropNode(const SharedHandle<DHTNode>& node)
{
if(cachedNodes_.size()) {
std::deque<SharedHandle<DHTNode> >::iterator itr =
std::find_if(nodes_.begin(), nodes_.end(), derefEqual(node));
if(itr != nodes_.end()) {
nodes_.erase(itr);
nodes_.push_back(cachedNodes_.front());
cachedNodes_.erase(cachedNodes_.begin());
}
}
}
void DHTBucket::moveToHead(const SharedHandle<DHTNode>& node)
{
std::deque<SharedHandle<DHTNode> >::iterator itr =
std::find_if(nodes_.begin(), nodes_.end(), derefEqual(node));
if(itr != nodes_.end()) {
nodes_.erase(itr);
nodes_.push_front(node);
}
}
void DHTBucket::moveToTail(const SharedHandle<DHTNode>& node)
{
std::deque<SharedHandle<DHTNode> >::iterator itr =
std::find_if(nodes_.begin(), nodes_.end(), derefEqual(node));
if(itr != nodes_.end()) {
nodes_.erase(itr);
nodes_.push_back(node);
}
}
bool DHTBucket::splitAllowed() const
{
return prefixLength_ < DHT_ID_LENGTH*8-1 && isInRange(localNode_);
}
SharedHandle<DHTBucket> DHTBucket::split()
{
assert(splitAllowed());
unsigned char rMax[DHT_ID_LENGTH];
memcpy(rMax, max_, DHT_ID_LENGTH);
bitfield::flipBit(rMax, DHT_ID_LENGTH, prefixLength_);
unsigned char rMin[DHT_ID_LENGTH];
memcpy(rMin, min_, DHT_ID_LENGTH);
bitfield::flipBit(min_, DHT_ID_LENGTH, prefixLength_);
++prefixLength_;
SharedHandle<DHTBucket> rBucket(new DHTBucket(prefixLength_,
rMax, rMin, localNode_));
std::deque<SharedHandle<DHTNode> > lNodes;
for(std::deque<SharedHandle<DHTNode> >::iterator i = nodes_.begin(),
eoi = nodes_.end(); i != eoi; ++i) {
if(rBucket->isInRange(*i)) {
assert(rBucket->addNode(*i));
} else {
lNodes.push_back(*i);
}
}
nodes_ = lNodes;
// TODO create toString() and use it.
A2_LOG_DEBUG(fmt("New bucket. prefixLength=%u, Range:%s-%s",
static_cast<unsigned int>(rBucket->getPrefixLength()),
util::toHex(rBucket->getMinID(), DHT_ID_LENGTH).c_str(),
util::toHex(rBucket->getMaxID(), DHT_ID_LENGTH).c_str()));
A2_LOG_DEBUG(fmt("Existing bucket. prefixLength=%u, Range:%s-%s",
static_cast<unsigned int>(prefixLength_),
util::toHex(getMinID(), DHT_ID_LENGTH).c_str(),
util::toHex(getMaxID(), DHT_ID_LENGTH).c_str()));
return rBucket;
}
void DHTBucket::getGoodNodes
(std::vector<SharedHandle<DHTNode> >& goodNodes) const
{
goodNodes.insert(goodNodes.end(), nodes_.begin(), nodes_.end());
goodNodes.erase(std::remove_if(goodNodes.begin(), goodNodes.end(),
mem_fun_sh(&DHTNode::isBad)), goodNodes.end());
}
SharedHandle<DHTNode> DHTBucket::getNode(const unsigned char* nodeID, const std::string& ipaddr, uint16_t port) const
{
SharedHandle<DHTNode> node(new DHTNode(nodeID));
node->setIPAddress(ipaddr);
node->setPort(port);
std::deque<SharedHandle<DHTNode> >::const_iterator itr =
std::find_if(nodes_.begin(), nodes_.end(), derefEqual(node));
if(itr == nodes_.end()) {
return SharedHandle<DHTNode>();
} else {
return *itr;
}
}
bool DHTBucket::operator==(const DHTBucket& bucket) const
{
return memcmp(max_, bucket.max_, DHT_ID_LENGTH) == 0 &&
memcmp(min_, bucket.min_, DHT_ID_LENGTH) == 0;
}
bool DHTBucket::needsRefresh() const
{
return nodes_.size() < K ||
lastUpdated_.difference(global::wallclock) >= DHT_BUCKET_REFRESH_INTERVAL;
}
void DHTBucket::notifyUpdate()
{
lastUpdated_ = global::wallclock;
}
namespace {
class FindQuestionableNode {
public:
bool operator()(const SharedHandle<DHTNode>& node) const
{
return node->isQuestionable();
}
};
} // namespace
bool DHTBucket::containsQuestionableNode() const
{
return std::find_if(nodes_.begin(), nodes_.end(), FindQuestionableNode()) != nodes_.end();
}
SharedHandle<DHTNode> DHTBucket::getLRUQuestionableNode() const
{
std::deque<SharedHandle<DHTNode> >::const_iterator i =
std::find_if(nodes_.begin(), nodes_.end(), FindQuestionableNode());
if(i == nodes_.end()) {
return SharedHandle<DHTNode>();
} else {
return *i;
}
}
} // namespace aria2