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/*
This file is part of cpp-ethereum.
cpp-ethereum 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 3 of the License, or
(at your option) any later version.
cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file BlockChainSync.h
* @author Gav Wood <i@gavwood.com>
* @date 2014
*/
#pragma once
#include <mutex>
#include <libdevcore/Guards.h>
#include <libdevcore/RangeMask.h>
#include <libethcore/Common.h>
#include <libp2p/Common.h>
#include "CommonNet.h"
#include "DownloadMan.h"
namespace dev
{
class RLPStream;
namespace eth
{
class EthereumHost;
class BlockQueue;
class EthereumPeer;
/**
* @brief Base BlockChain synchronization strategy class.
* Syncs to peers and keeps up to date. Base class handles blocks downloading but does not contain any details on state transfer logic.
*/
class BlockChainSync: public HasInvariants
{
public:
BlockChainSync(EthereumHost& _host);
virtual ~BlockChainSync();
void abortSync(); ///< Abort all sync activity
DownloadMan const& downloadMan() const;
DownloadMan& downloadMan();
/// @returns true is Sync is in progress
virtual bool isSyncing() const = 0;
/// Called by peer to report status
virtual void onPeerStatus(EthereumPeer* _peer);
/// Called by peer once it has new blocks during syn
virtual void onPeerBlocks(EthereumPeer* _peer, RLP const& _r);
/// Called by peer once it has new blocks
virtual void onPeerNewBlock(EthereumPeer* _peer, RLP const& _r);
/// Called by peer once it has new hashes
virtual void onPeerNewHashes(EthereumPeer* _peer, h256s const& _hashes) = 0;
/// Called by peer once it has another sequential block of hashes during sync
virtual void onPeerHashes(EthereumPeer* _peer, h256s const& _hashes) = 0;
/// Called by peer when it is disconnecting
virtual void onPeerAborting(EthereumPeer* _peer) = 0;
/// @returns Synchonization status
virtual SyncStatus status() const = 0;
static char const* stateName(SyncState _s) { return s_stateNames[static_cast<int>(_s)]; }
protected:
//To be implemented in derived classes:
/// New valid peer appears
virtual void onNewPeer(EthereumPeer* _peer) = 0;
/// Peer done downloading blocks
virtual void peerDoneBlocks(EthereumPeer* _peer) = 0;
/// Resume downloading after witing state
virtual void continueSync() = 0;
/// Restart sync
virtual void restartSync() = 0;
/// Called after all blocks have been donloaded
virtual void completeSync() = 0;
/// Enter waiting state
virtual void pauseSync() = 0;
/// Restart sync for given peer
virtual void resetSyncFor(EthereumPeer* _peer, h256 const& _latestHash, u256 const& _td) = 0;
EthereumHost& host() { return m_host; }
EthereumHost const& host() const { return m_host; }
/// Estimates max number of hashes peers can give us.
unsigned estimatedHashes() const;
/// Request blocks from peer if needed
void requestBlocks(EthereumPeer* _peer);
protected:
Handler m_bqRoomAvailable; ///< Triggered once block queue
mutable RecursiveMutex x_sync;
SyncState m_state = SyncState::Idle; ///< Current sync state
unsigned m_estimatedHashes = 0; ///< Number of estimated hashes for the last peer over PV60. Used for status reporting only.
private:
static char const* const s_stateNames[static_cast<int>(SyncState::Size)];
bool invariants() const override = 0;
EthereumHost& m_host;
HashDownloadMan m_hashMan;
};
/**
* @brief Syncrhonization over PV60. Selects a single peer and tries to downloading hashes from it. After hash downaload is complete
* Syncs to peers and keeps up to date
*/
/**
* Transitions:
*
* Idle->Hashes
* Triggered when:
* * A new peer appears that we can sync to
* * Transtition to Idle, there are peers we can sync to
* Effects:
* * Set chain sync (m_syncingTotalDifficulty, m_syncingLatestHash, m_syncer)
* * Requests hashes from m_syncer
*
* Hashes->Idle
* Triggered when:
* * Received too many hashes
* * Received 0 total hashes from m_syncer
* * m_syncer aborts
* Effects:
* In case of too many hashes sync is reset
*
* Hashes->Blocks
* Triggered when:
* * Received known hash from m_syncer
* * Received 0 hashes from m_syncer and m_syncingTotalBlocks not empty
* Effects:
* * Set up download manager, clear m_syncingTotalBlocks. Set all peers to help with downloading if they can
*
* Blocks->Idle
* Triggered when:
* * m_syncer aborts
* * m_syncer does not have required block
* * All blocks downloaded
* * Block qeueue is full with unknown blocks
* Effects:
* * Download manager is reset
*
* Blocks->Waiting
* Triggered when:
* * Block queue is full with known blocks
* Effects:
* * Stop requesting blocks from peers
*
* Waiting->Blocks
* Triggered when:
* * Block queue has space for new blocks
* Effects:
* * Continue requesting blocks from peers
*
* Idle->NewBlocks
* Triggered when:
* * New block hashes arrive
* Effects:
* * Set up download manager, clear m_syncingTotalBlocks. Download blocks from a single peer. If downloaded blocks have unknown parents, set the peer to sync
*
* NewBlocks->Idle
* Triggered when:
* * m_syncer aborts
* * m_syncer does not have required block
* * All new blocks downloaded
* * Block qeueue is full with unknown blocks
* Effects:
* * Download manager is reset
*
*/
class PV60Sync: public BlockChainSync
{
public:
PV60Sync(EthereumHost& _host);
/// @returns true is Sync is in progress
bool isSyncing() const override { return !!m_syncer; }
/// Called by peer once it has new hashes
void onPeerNewHashes(EthereumPeer* _peer, h256s const& _hashes) override;
/// Called by peer once it has another sequential block of hashes during sync
void onPeerHashes(EthereumPeer* _peer, h256s const& _hashes) override;
/// Called by peer when it is disconnecting
void onPeerAborting(EthereumPeer* _peer) override;
/// @returns Sync status
SyncStatus status() const override;
protected:
void onNewPeer(EthereumPeer* _peer) override;
void continueSync() override;
void peerDoneBlocks(EthereumPeer* _peer) override;
void restartSync() override;
void completeSync() override;
void pauseSync() override;
void resetSyncFor(EthereumPeer* _peer, h256 const& _latestHash, u256 const& _td) override;
private:
/// Transition sync state in a particular direction. @param _peer Peer that is responsible for state tranfer
void transition(EthereumPeer* _peer, SyncState _s, bool _force = false, bool _needHelp = true);
/// Reset peer syncing requirements state.
void resetNeedsSyncing(EthereumPeer* _peer) { setNeedsSyncing(_peer, h256(), 0); }
/// Update peer syncing requirements state.
void setNeedsSyncing(EthereumPeer* _peer, h256 const& _latestHash, u256 const& _td);
/// Do we presently need syncing with this peer?
bool needsSyncing(EthereumPeer* _peer) const;
/// Check whether the session should bother grabbing blocks from a peer.
bool shouldGrabBlocks(EthereumPeer* _peer) const;
/// Attempt to begin syncing with the peer; first check the peer has a more difficlult chain to download, then start asking for hashes, then move to blocks
void attemptSync(EthereumPeer* _peer);
/// Update our syncing state
void setState(EthereumPeer* _peer, SyncState _s, bool _isSyncing = false, bool _needHelp = false);
/// Check if peer is main syncer
bool isSyncing(EthereumPeer* _peer) const;
/// Check if we need (re-)syncing with the peer.
void noteNeedsSyncing(EthereumPeer* _who);
/// Set main syncing peer
void changeSyncer(EthereumPeer* _syncer, bool _needHelp);
/// Called when peer done downloading blocks
void noteDoneBlocks(EthereumPeer* _who, bool _clemency);
/// Abort syncing for peer
void abortSync(EthereumPeer* _peer);
/// Reset hash chain syncing
void resetSync();
bool invariants() const override;
h256s m_syncingNeededBlocks; ///< The blocks that we should download from this peer.
h256 m_syncingLastReceivedHash; ///< Hash most recently received from peer.
h256 m_syncingLatestHash; ///< Latest block's hash of the peer we are syncing to, as of the current sync.
u256 m_syncingTotalDifficulty; ///< Latest block's total difficulty of the peer we aresyncing to, as of the current sync.
// TODO: switch to weak_ptr
EthereumPeer* m_syncer = nullptr; ///< Peer we are currently syncing with
};
}
}