EthereumHost.cpp

/*
	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 EthereumHost.cpp
 * @author Gav Wood <i@gavwood.com>
 * @date 2014
 */

#include "EthereumHost.h"

#include <chrono>
#include <thread>
#include <libdevcore/Common.h>
#include <libp2p/Host.h>
#include <libp2p/Session.h>
#include <libethcore/Exceptions.h>
#include "BlockChain.h"
#include "TransactionQueue.h"
#include "BlockQueue.h"
#include "EthereumPeer.h"
#include "BlockChainSync.h"

using namespace std;
using namespace dev;
using namespace dev::eth;
using namespace p2p;

unsigned const EthereumHost::c_oldProtocolVersion = 62; //TODO: remove this once v63+ is common
static unsigned const c_maxSendTransactions = 256;

char const* const EthereumHost::s_stateNames[static_cast<int>(SyncState::Size)] = {"NotSynced", "Idle", "Waiting", "Blocks", "State"};

#if defined(_WIN32)
const char* EthereumHostTrace::name() { return EthPurple "^" EthGray "  "; }
#else
const char* EthereumHostTrace::name() { return EthPurple "⧫" EthGray " "; }
#endif

namespace
{
class EthereumPeerObserver: public EthereumPeerObserverFace
{
public:
	EthereumPeerObserver(shared_ptr<BlockChainSync> _sync, TransactionQueue& _tq): m_sync(_sync), m_tq(_tq) {}

	void onPeerStatus(std::shared_ptr<EthereumPeer> _peer) override
	{
		try
		{
			m_sync->onPeerStatus(_peer);
		}
		catch (FailedInvariant const&)
		{
			// "fix" for https://github.com/ethereum/webthree-umbrella/issues/300
			clog(NetWarn) << "Failed invariant during sync, restarting sync";
			m_sync->restartSync();
		}
	}

	void onPeerTransactions(std::shared_ptr<EthereumPeer> _peer, RLP const& _r) override
	{
		unsigned itemCount = _r.itemCount();
		clog(EthereumHostTrace) << "Transactions (" << dec << itemCount << "entries)";
		m_tq.enqueue(_r, _peer->id());
	}

	void onPeerAborting() override
	{
		try
		{
			m_sync->onPeerAborting();
		}
		catch (Exception&)
		{
			cwarn << "Exception on peer destruciton: " << boost::current_exception_diagnostic_information();
		}
	}

	void onPeerBlockHeaders(std::shared_ptr<EthereumPeer> _peer, RLP const& _headers) override
	{
		try
		{
			m_sync->onPeerBlockHeaders(_peer, _headers);
		}
		catch (FailedInvariant const&)
		{
			// "fix" for https://github.com/ethereum/webthree-umbrella/issues/300
			clog(NetWarn) << "Failed invariant during sync, restarting sync";
			m_sync->restartSync();
		}
	}

	void onPeerBlockBodies(std::shared_ptr<EthereumPeer> _peer, RLP const& _r) override
	{
		try
		{
			m_sync->onPeerBlockBodies(_peer, _r);
		}
		catch (FailedInvariant const&)
		{
			// "fix" for https://github.com/ethereum/webthree-umbrella/issues/300
			clog(NetWarn) << "Failed invariant during sync, restarting sync";
			m_sync->restartSync();
		}
	}

	void onPeerNewHashes(std::shared_ptr<EthereumPeer> _peer, std::vector<std::pair<h256, u256>> const& _hashes) override
	{
		try
		{
			m_sync->onPeerNewHashes(_peer, _hashes);
		}
		catch (FailedInvariant const&)
		{
			// "fix" for https://github.com/ethereum/webthree-umbrella/issues/300
			clog(NetWarn) << "Failed invariant during sync, restarting sync";
			m_sync->restartSync();
		}
	}

	void onPeerNewBlock(std::shared_ptr<EthereumPeer> _peer, RLP const& _r) override
	{
		try
		{
			m_sync->onPeerNewBlock(_peer, _r);
		}
		catch (FailedInvariant const&)
		{
			// "fix" for https://github.com/ethereum/webthree-umbrella/issues/300
			clog(NetWarn) << "Failed invariant during sync, restarting sync";
			m_sync->restartSync();
		}
	}

	void onPeerNodeData(std::shared_ptr<EthereumPeer> /* _peer */, RLP const& _r) override
	{
		unsigned itemCount = _r.itemCount();
		clog(EthereumHostTrace) << "Node Data (" << dec << itemCount << "entries)";
	}

	void onPeerReceipts(std::shared_ptr<EthereumPeer> /* _peer */, RLP const& _r) override
	{
		unsigned itemCount = _r.itemCount();
		clog(EthereumHostTrace) << "Receipts (" << dec << itemCount << "entries)";
	}

private:
	shared_ptr<BlockChainSync> m_sync;
	TransactionQueue& m_tq;
};

class EthereumHostData: public EthereumHostDataFace
{
public:
	EthereumHostData(BlockChain const& _chain, OverlayDB const& _db): m_chain(_chain), m_db(_db) {}

	pair<bytes, unsigned> blockHeaders(RLP const& _blockId, unsigned _maxHeaders, u256 _skip, bool _reverse) const override
	{
		auto numHeadersToSend = _maxHeaders;

		auto step = static_cast<unsigned>(_skip) + 1;
		assert(step > 0 && "step must not be 0");

		h256 blockHash;
		if (_blockId.size() == 32) // block id is a hash
		{
			blockHash = _blockId.toHash<h256>();
			clog(NetMessageSummary) << "GetBlockHeaders (block (hash): " << blockHash
				<< ", maxHeaders: " << _maxHeaders
				<< ", skip: " << _skip << ", reverse: " << _reverse << ")";

			if (!m_chain.isKnown(blockHash))
				blockHash = {};
			else if (!_reverse)
			{
				auto n = m_chain.number(blockHash);
				if (numHeadersToSend == 0)
					blockHash = {};
				else if (n != 0 || blockHash == m_chain.genesisHash())
				{
					auto top = n + uint64_t(step) * numHeadersToSend - 1;
					auto lastBlock = m_chain.number();
					if (top > lastBlock)
					{
						numHeadersToSend = (lastBlock - n) / step + 1;
						top = n + step * (numHeadersToSend - 1);
					}
					assert(top <= lastBlock && "invalid top block calculated");
					blockHash = m_chain.numberHash(static_cast<unsigned>(top)); // override start block hash with the hash of the top block we have
				}
				else
					blockHash = {};
			}
		}
		else // block id is a number
		{
			auto n = _blockId.toInt<bigint>();
			clog(NetMessageSummary) << "GetBlockHeaders (" << n
			<< "max: " << _maxHeaders
			<< "skip: " << _skip << (_reverse ? "reverse" : "") << ")";

			if (!_reverse)
			{
				auto lastBlock = m_chain.number();
				if (n > lastBlock || numHeadersToSend == 0)
					blockHash = {};
				else
				{
					bigint top = n + uint64_t(step) * (numHeadersToSend - 1);
					if (top > lastBlock)
					{
						numHeadersToSend = (lastBlock - static_cast<unsigned>(n)) / step + 1;
						top = n + step * (numHeadersToSend - 1);
					}
					assert(top <= lastBlock && "invalid top block calculated");
					blockHash = m_chain.numberHash(static_cast<unsigned>(top)); // override start block hash with the hash of the top block we have
				}
			}
			else if (n <= std::numeric_limits<unsigned>::max())
				blockHash = m_chain.numberHash(static_cast<unsigned>(n));
			else
				blockHash = {};
		}

		auto nextHash = [this](h256 _h, unsigned _step)
		{
			static const unsigned c_blockNumberUsageLimit = 1000;

			const auto lastBlock = m_chain.number();
			const auto limitBlock = lastBlock > c_blockNumberUsageLimit ? lastBlock - c_blockNumberUsageLimit : 0; // find the number of the block below which we don't expect BC changes.

			while (_step) // parent hash traversal
			{
				auto details = m_chain.details(_h);
				if (details.number < limitBlock)
					break; // stop using parent hash traversal, fallback to using block numbers
				_h = details.parent;
				--_step;
			}

			if (_step) // still need lower block
			{
				auto n = m_chain.number(_h);
				if (n >= _step)
					_h = m_chain.numberHash(n - _step);
				else
					_h = {};
			}


			return _h;
		};

		bytes rlp;
		unsigned itemCount = 0;
		vector<h256> hashes;
		for (unsigned i = 0; i != numHeadersToSend; ++i)
		{
			if (!blockHash || !m_chain.isKnown(blockHash))
				break;

			hashes.push_back(blockHash);
			++itemCount;

			blockHash = nextHash(blockHash, step);
		}

		for (unsigned i = 0; i < hashes.size() && rlp.size() < c_maxPayload; ++i)
			rlp += m_chain.headerData(hashes[_reverse ? i : hashes.size() - 1 - i]);

		return make_pair(rlp, itemCount);
	}

	pair<bytes, unsigned> blockBodies(RLP const& _blockHashes) const override
	{
		unsigned const count = static_cast<unsigned>(_blockHashes.itemCount());

		bytes rlp;
		unsigned n = 0;
		auto numBodiesToSend = std::min(count, c_maxBlocks);
		for (unsigned i = 0; i < numBodiesToSend && rlp.size() < c_maxPayload; ++i)
		{
			auto h = _blockHashes[i].toHash<h256>();
			if (m_chain.isKnown(h))
			{
				bytes blockBytes = m_chain.block(h);
				RLP block{blockBytes};
				RLPStream body;
				body.appendList(2);
				body.appendRaw(block[1].data()); // transactions
				body.appendRaw(block[2].data()); // uncles
				auto bodyBytes = body.out();
				rlp.insert(rlp.end(), bodyBytes.begin(), bodyBytes.end());
				++n;
			}
		}
		if (count > 20 && n == 0)
			clog(NetWarn) << "all" << count << "unknown blocks requested; peer on different chain?";
		else
			clog(NetMessageSummary) << n << "blocks known and returned;" << (numBodiesToSend - n) << "blocks unknown;" << (count > c_maxBlocks ? count - c_maxBlocks : 0) << "blocks ignored";

		return make_pair(rlp, n);
	}

	strings nodeData(RLP const& _dataHashes) const override
	{
		unsigned const count = static_cast<unsigned>(_dataHashes.itemCount());

		strings data;
		size_t payloadSize = 0;
		auto numItemsToSend = std::min(count, c_maxNodes);
		for (unsigned i = 0; i < numItemsToSend && payloadSize < c_maxPayload; ++i)
		{
			auto h = _dataHashes[i].toHash<h256>();
			auto node = m_db.lookup(h);
			if (!node.empty())
			{
				payloadSize += node.length();
				data.push_back(move(node));
			}
		}
		clog(NetMessageSummary) << data.size() << " nodes known and returned;" << (numItemsToSend - data.size()) << " unknown;" << (count > c_maxNodes ? count - c_maxNodes : 0) << " ignored";

		return data;
	}

	pair<bytes, unsigned> receipts(RLP const& _blockHashes) const override
	{
		unsigned const count = static_cast<unsigned>(_blockHashes.itemCount());

		bytes rlp;
		unsigned n = 0;
		auto numItemsToSend = std::min(count, c_maxReceipts);
		for (unsigned i = 0; i < numItemsToSend && rlp.size() < c_maxPayload; ++i)
		{
			auto h = _blockHashes[i].toHash<h256>();
			if (m_chain.isKnown(h))
			{
				auto const receipts = m_chain.receipts(h);
				auto receiptsRlpList = receipts.rlp();
				rlp.insert(rlp.end(), receiptsRlpList.begin(), receiptsRlpList.end());
				++n;
			}
		}
		clog(NetMessageSummary) << n << " receipt lists known and returned;" << (numItemsToSend - n) << " unknown;" << (count > c_maxReceipts ? count - c_maxReceipts : 0) << " ignored";

		return make_pair(rlp, n);
	}

private:
	BlockChain const& m_chain;
	OverlayDB const& m_db;
};

}

EthereumHost::EthereumHost(BlockChain const& _ch, OverlayDB const& _db, TransactionQueue& _tq, BlockQueue& _bq, u256 _networkId):
	HostCapability<EthereumPeer>(),
	Worker		("ethsync"),
	m_chain		(_ch),
	m_db(_db),
	m_tq		(_tq),
	m_bq		(_bq),
	m_networkId	(_networkId),
	m_hostData(make_shared<EthereumHostData>(m_chain, m_db))
{
	// TODO: Composition would be better. Left like that to avoid initialization
	//       issues as BlockChainSync accesses other EthereumHost members.
	m_sync.reset(new BlockChainSync(*this));
	m_peerObserver = make_shared<EthereumPeerObserver>(m_sync, m_tq);
	m_latestBlockSent = _ch.currentHash();
	m_tq.onImport([this](ImportResult _ir, h256 const& _h, h512 const& _nodeId) { onTransactionImported(_ir, _h, _nodeId); });
}

EthereumHost::~EthereumHost()
{
	terminate();
}

bool EthereumHost::ensureInitialised()
{
	if (!m_latestBlockSent)
	{
		// First time - just initialise.
		m_latestBlockSent = m_chain.currentHash();
		clog(EthereumHostTrace) << "Initialising: latest=" << m_latestBlockSent;

		Guard l(x_transactions);
		m_transactionsSent = m_tq.knownTransactions();
		return true;
	}
	return false;
}

void EthereumHost::reset()
{
	m_sync->abortSync();

	m_latestBlockSent = h256();
	Guard tl(x_transactions);
	m_transactionsSent.clear();
}

void EthereumHost::completeSync()
{
	m_sync->completeSync();
}

void EthereumHost::doWork()
{
	bool netChange = ensureInitialised();
	auto h = m_chain.currentHash();
	// If we've finished our initial sync (including getting all the blocks into the chain so as to reduce invalid transactions), start trading transactions & blocks
	if (!isSyncing() && m_chain.isKnown(m_latestBlockSent))
	{
		if (m_newTransactions)
		{
			m_newTransactions = false;
			maintainTransactions();
		}
		if (m_newBlocks)
		{
			m_newBlocks = false;
			maintainBlocks(h);
		}
	}

	time_t  now = std::chrono::system_clock::to_time_t(chrono::system_clock::now());
	if (now - m_lastTick >= 1)
	{
		m_lastTick = now;
		foreachPeer([](std::shared_ptr<EthereumPeer> _p) { _p->tick(); return true; });
	}

//	return netChange;
	// TODO: Figure out what to do with netChange.
	(void)netChange;
}

void EthereumHost::maintainTransactions()
{
	// Send any new transactions.
	unordered_map<std::shared_ptr<EthereumPeer>, std::vector<size_t>> peerTransactions;
	auto ts = m_tq.topTransactions(c_maxSendTransactions);
	{
		Guard l(x_transactions);
		for (size_t i = 0; i < ts.size(); ++i)
		{
			auto const& t = ts[i];
			bool unsent = !m_transactionsSent.count(t.sha3());
			auto peers = get<1>(randomSelection(0, [&](EthereumPeer* p) { return p->m_requireTransactions || (unsent && !p->m_knownTransactions.count(t.sha3())); }));
			for (auto const& p: peers)
				peerTransactions[p].push_back(i);
		}
		for (auto const& t: ts)
			m_transactionsSent.insert(t.sha3());
	}
	foreachPeer([&](shared_ptr<EthereumPeer> _p)
	{
		bytes b;
		unsigned n = 0;
		for (auto const& i: peerTransactions[_p])
		{
			_p->m_knownTransactions.insert(ts[i].sha3());
			b += ts[i].rlp();
			++n;
		}

		_p->clearKnownTransactions();

		if (n || _p->m_requireTransactions)
		{
			RLPStream ts;
			_p->prep(ts, TransactionsPacket, n).appendRaw(b, n);
			_p->sealAndSend(ts);
			clog(EthereumHostTrace) << "Sent" << n << "transactions to " << _p->session()->info().clientVersion;
		}
		_p->m_requireTransactions = false;
		return true;
	});
}

void EthereumHost::foreachPeer(std::function<bool(std::shared_ptr<EthereumPeer>)> const& _f) const
{
	//order peers by protocol, rating, connection age
	auto sessions = peerSessions();
	auto sessionLess = [](std::pair<std::shared_ptr<SessionFace>, std::shared_ptr<Peer>> const& _left, std::pair<std::shared_ptr<SessionFace>, std::shared_ptr<Peer>> const& _right)
		{ return _left.first->rating() == _right.first->rating() ? _left.first->connectionTime() < _right.first->connectionTime() : _left.first->rating() > _right.first->rating(); };

	std::sort(sessions.begin(), sessions.end(), sessionLess);
	for (auto s: sessions)
		if (!_f(capabilityFromSession<EthereumPeer>(*s.first)))
			return;

	sessions = peerSessions(c_oldProtocolVersion); //TODO: remove once v61+ is common
	std::sort(sessions.begin(), sessions.end(), sessionLess);
	for (auto s: sessions)
		if (!_f(capabilityFromSession<EthereumPeer>(*s.first, c_oldProtocolVersion)))
			return;
}

tuple<vector<shared_ptr<EthereumPeer>>, vector<shared_ptr<EthereumPeer>>, vector<shared_ptr<SessionFace>>> EthereumHost::randomSelection(unsigned _percent, std::function<bool(EthereumPeer*)> const& _allow)
{
	vector<shared_ptr<EthereumPeer>> chosen;
	vector<shared_ptr<EthereumPeer>> allowed;
	vector<shared_ptr<SessionFace>> sessions;

	size_t peerCount = 0;
	foreachPeer([&](std::shared_ptr<EthereumPeer> _p)
	{
		if (_allow(_p.get()))
		{
			allowed.push_back(_p);
			sessions.push_back(_p->session());
		}
		++peerCount;
		return true;
	});

	size_t chosenSize = (peerCount * _percent + 99) / 100;
	chosen.reserve(chosenSize);
	for (unsigned i = chosenSize; i && allowed.size(); i--)
	{
		unsigned n = rand() % allowed.size();
		chosen.push_back(std::move(allowed[n]));
		allowed.erase(allowed.begin() + n);
	}
	return make_tuple(move(chosen), move(allowed), move(sessions));
}

void EthereumHost::maintainBlocks(h256 const& _currentHash)
{
	// Send any new blocks.
	auto detailsFrom = m_chain.details(m_latestBlockSent);
	auto detailsTo = m_chain.details(_currentHash);
	if (detailsFrom.totalDifficulty < detailsTo.totalDifficulty)
	{
		if (diff(detailsFrom.number, detailsTo.number) < 20)
		{
			// don't be sending more than 20 "new" blocks. if there are any more we were probably waaaay behind.
			clog(EthereumHostTrace) << "Sending a new block (current is" << _currentHash << ", was" << m_latestBlockSent << ")";

			h256s blocks = get<0>(m_chain.treeRoute(m_latestBlockSent, _currentHash, false, false, true));

			auto s = randomSelection(25, [&](EthereumPeer* p){
				DEV_GUARDED(p->x_knownBlocks)
					return !p->m_knownBlocks.count(_currentHash);
				return false;
			});
			for (shared_ptr<EthereumPeer> const& p: get<0>(s))
				for (auto const& b: blocks)
				{
					RLPStream ts;
					p->prep(ts, NewBlockPacket, 2).appendRaw(m_chain.block(b), 1).append(m_chain.details(b).totalDifficulty);

					Guard l(p->x_knownBlocks);
					p->sealAndSend(ts);
					p->m_knownBlocks.clear();
				}
			for (shared_ptr<EthereumPeer> const& p: get<1>(s))
			{
				RLPStream ts;
				p->prep(ts, NewBlockHashesPacket, blocks.size());
				for (auto const& b: blocks)
				{
					ts.appendList(2);
					ts.append(b);
					ts.append(m_chain.number(b));
				}

				Guard l(p->x_knownBlocks);
				p->sealAndSend(ts);
				p->m_knownBlocks.clear();
			}
		}
		m_latestBlockSent = _currentHash;
	}
}

bool EthereumHost::isSyncing() const
{
	return m_sync->isSyncing();
}

SyncStatus EthereumHost::status() const
{
	return m_sync->status();
}

void EthereumHost::onTransactionImported(ImportResult _ir, h256 const& _h, h512 const& _nodeId)
{
	auto session = host()->peerSession(_nodeId);
	if (!session)
		return;

	std::shared_ptr<EthereumPeer> peer = capabilityFromSession<EthereumPeer>(*session);
	if (!peer)
		peer = capabilityFromSession<EthereumPeer>(*session, c_oldProtocolVersion);
	if (!peer)
		return;

	Guard l(peer->x_knownTransactions);
	peer->m_knownTransactions.insert(_h);
	switch (_ir)
	{
	case ImportResult::Malformed:
		peer->addRating(-100);
		break;
	case ImportResult::AlreadyKnown:
		// if we already had the transaction, then don't bother sending it on.
		DEV_GUARDED(x_transactions)
			m_transactionsSent.insert(_h);
		peer->addRating(0);
		break;
	case ImportResult::Success:
		peer->addRating(100);
		break;
	default:;
	}
}

shared_ptr<Capability> EthereumHost::newPeerCapability(shared_ptr<SessionFace> const& _s, unsigned _idOffset, p2p::CapDesc const& _cap)
{
	auto ret = HostCapability<EthereumPeer>::newPeerCapability(_s, _idOffset, _cap);

	auto cap = capabilityFromSession<EthereumPeer>(*_s, _cap.second);
	assert(cap);
	cap->init(
		protocolVersion(),
		m_networkId,
		m_chain.details().totalDifficulty,
		m_chain.currentHash(),
		m_chain.genesisHash(),
		m_hostData,
		m_peerObserver
	);

	return ret;
}