Commit d81590c8 authored by Pieter Wuille's avatar Pieter Wuille Committed by Tom Zander

BIP9 Implementation

Inspired by former implementations by Eric Lombrozo and Rusty Russell, and
based on code by Jorge Timon.

Conflicts:
	src/main.cpp
	src/miner.cpp
parent 3796d87c
......@@ -163,6 +163,7 @@ BITCOIN_CORE_H = \
utiltime.h \
validationinterface.h \
version.h \
versionbits.h \
wallet/crypter.h \
wallet/db.h \
wallet/wallet.h \
......@@ -214,6 +215,7 @@ libbitcoin_server_a_SOURCES = \
txdb.cpp \
txmempool.cpp \
validationinterface.cpp \
versionbits.cpp \
$(BITCOIN_CORE_H)
if ENABLE_ZMQ
......
......@@ -14,8 +14,6 @@
#include <vector>
#include <boost/foreach.hpp>
struct CDiskBlockPos
{
int nFile;
......
......@@ -81,6 +81,8 @@ public:
consensus.nPowTargetSpacing = 10 * 60;
consensus.fPowAllowMinDifficultyBlocks = false;
consensus.fPowNoRetargeting = false;
consensus.nRuleChangeActivationThreshold = 1916; // 95% of 2016
consensus.nMinerConfirmationWindow = 2016; // nPowTargetTimespan / nPowTargetSpacing
/**
* The message start string is designed to be unlikely to occur in normal data.
* The characters are rarely used upper ASCII, not valid as UTF-8, and produce
......@@ -168,6 +170,8 @@ public:
consensus.nPowTargetSpacing = 10 * 60;
consensus.fPowAllowMinDifficultyBlocks = true;
consensus.fPowNoRetargeting = false;
consensus.nRuleChangeActivationThreshold = 1512; // 75% for testchains
consensus.nMinerConfirmationWindow = 2016; // nPowTargetTimespan / nPowTargetSpacing
pchMessageStart[0] = 0x0b;
pchMessageStart[1] = 0x11;
pchMessageStart[2] = 0x09;
......@@ -237,6 +241,8 @@ public:
consensus.nPowTargetSpacing = 10 * 60;
consensus.fPowAllowMinDifficultyBlocks = true;
consensus.fPowNoRetargeting = true;
consensus.nRuleChangeActivationThreshold = 108; // 75% for testchains
consensus.nMinerConfirmationWindow = 144; // Faster than normal for regtest (144 instead of 2016)
pchMessageStart[0] = 0xfa;
pchMessageStart[1] = 0xbf;
......
......@@ -7,8 +7,28 @@
#define BITCOIN_CONSENSUS_PARAMS_H
#include "uint256.h"
#include <map>
#include <string>
namespace Consensus {
enum DeploymentPos
{
MAX_VERSION_BITS_DEPLOYMENTS = 0,
};
/**
* Struct for each individual consensus rule change using BIP9.
*/
struct BIP9Deployment {
/** Bit position to select the particular bit in nVersion. */
int bit;
/** Start MedianTime for version bits miner confirmation. Can be a date in the past */
int64_t nStartTime;
/** Timeout/expiry MedianTime for the deployment attempt. */
int64_t nTimeout;
};
/**
* Parameters that influence chain consensus.
*/
......@@ -22,6 +42,14 @@ struct Params {
/** Block height and hash at which BIP34 becomes active */
int BIP34Height;
uint256 BIP34Hash;
/**
* Minimum blocks including miner confirmation of the total of 2016 blocks in a retargetting period,
* (nPowTargetTimespan / nPowTargetSpacing) which is also used for BIP9 deployments.
* Examples: 1916 for 95%, 1512 for testchains.
*/
uint32_t nRuleChangeActivationThreshold;
uint32_t nMinerConfirmationWindow;
BIP9Deployment vDeployments[MAX_VERSION_BITS_DEPLOYMENTS];
/** Proof of work parameters */
uint256 powLimit;
bool fPowAllowMinDifficultyBlocks;
......
......@@ -496,7 +496,7 @@ std::string HelpMessage(HelpMessageMode mode)
strUsage += HelpMessageOpt("-blockmaxsize=<n>", _("Set maximum block size in bytes (default is equal to network max-block-size)"));
strUsage += HelpMessageOpt("-blockprioritysize=<n>", strprintf(_("Set maximum size of high-priority/low-fee transactions in bytes (default: %d)"), DEFAULT_BLOCK_PRIORITY_SIZE));
if (showDebug)
strUsage += HelpMessageOpt("-blockversion=<n>", strprintf("Override block version to test forking scenarios (default: %d)", (int)CBlock::CURRENT_VERSION));
strUsage += HelpMessageOpt("-blockversion=<n>", "Override block version to test forking scenarios");
strUsage += HelpMessageGroup(_("RPC server options:"));
strUsage += HelpMessageOpt("-server", _("Accept command line and JSON-RPC commands"));
......
......@@ -34,6 +34,7 @@
#include "utilmoneystr.h"
#include "utilstrencodings.h"
#include "validationinterface.h"
#include "versionbits.h"
#include <sstream>
......@@ -2182,6 +2183,51 @@ void PartitionCheck(bool (*initialDownloadCheck)(), CCriticalSection& cs, const
}
}
// Protected by cs_main
static VersionBitsCache versionbitscache;
int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params)
{
LOCK(cs_main);
int32_t nVersion = VERSIONBITS_TOP_BITS;
for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; i++) {
ThresholdState state = VersionBitsState(pindexPrev, params, (Consensus::DeploymentPos)i, versionbitscache);
if (state == THRESHOLD_LOCKED_IN || state == THRESHOLD_STARTED) {
nVersion |= VersionBitsMask(params, (Consensus::DeploymentPos)i);
}
}
return nVersion;
}
/**
* Threshold condition checker that triggers when unknown versionbits are seen on the network.
*/
class WarningBitsConditionChecker : public AbstractThresholdConditionChecker
{
private:
int bit;
public:
WarningBitsConditionChecker(int bitIn) : bit(bitIn) {}
int64_t BeginTime(const Consensus::Params& params) const { return 0; }
int64_t EndTime(const Consensus::Params& params) const { return std::numeric_limits<int64_t>::max(); }
int Period(const Consensus::Params& params) const { return params.nMinerConfirmationWindow; }
int Threshold(const Consensus::Params& params) const { return params.nRuleChangeActivationThreshold; }
bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const
{
return ((pindex->nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS) &&
((pindex->nVersion >> bit) & 1) != 0 &&
((ComputeBlockVersion(pindex->pprev, params) >> bit) & 1) == 0;
}
};
// Protected by cs_main
static ThresholdConditionCache warningcache[VERSIONBITS_NUM_BITS];
static int64_t nTimeCheck = 0;
static int64_t nTimeForks = 0;
static int64_t nTimeVerify = 0;
......@@ -2577,6 +2623,47 @@ void static UpdateTip(CBlockIndex *pindexNew) {
Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), chainActive.Tip()), pcoinsTip->DynamicMemoryUsage() * (1.0 / (1<<20)), pcoinsTip->GetCacheSize());
cvBlockChange.notify_all();
// Check the version of the last 100 blocks to see if we need to upgrade:
static bool fWarned = false;
if (!IsInitialBlockDownload())
{
int nUpgraded = 0;
const CBlockIndex* pindex = chainActive.Tip();
for (int bit = 0; bit < VERSIONBITS_NUM_BITS; bit++) {
WarningBitsConditionChecker checker(bit);
ThresholdState state = checker.GetStateFor(pindex, chainParams.GetConsensus(), warningcache[bit]);
if (state == THRESHOLD_ACTIVE || state == THRESHOLD_LOCKED_IN) {
if (state == THRESHOLD_ACTIVE) {
strMiscWarning = strprintf(_("Warning: unknown new rules activated (versionbit %i)"), bit);
if (!fWarned) {
CAlert::Notify(strMiscWarning, true);
fWarned = true;
}
} else {
LogPrintf("%s: unknown new rules are about to activate (versionbit %i)\n", __func__, bit);
}
}
}
for (int i = 0; i < 100 && pindex != NULL; i++)
{
int32_t nExpectedVersion = ComputeBlockVersion(pindex->pprev, chainParams.GetConsensus());
if (pindex->nVersion > VERSIONBITS_LAST_OLD_BLOCK_VERSION && (pindex->nVersion & ~nExpectedVersion) != 0)
++nUpgraded;
pindex = pindex->pprev;
}
if (nUpgraded > 0)
LogPrintf("%s: %d of last 100 blocks have unexpected version\n", __func__, nUpgraded);
if (nUpgraded > 100/2)
{
// strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
strMiscWarning = _("Warning: Unknown block versions being mined! It's possible unknown rules are in effect");
if (!fWarned) {
CAlert::Notify(strMiscWarning, true);
fWarned = true;
}
}
}
}
/** Disconnect chainActive's tip. You probably want to call mempool.removeForReorg and manually re-limit mempool size after this, with cs_main held. */
......@@ -3912,6 +3999,10 @@ void UnloadBlockIndex()
setDirtyFileInfo.clear();
mapNodeState.clear();
recentRejects.reset(NULL);
versionbitscache.Clear();
for (int b = 0; b < VERSIONBITS_NUM_BITS; b++) {
warningcache[b].clear();
}
BOOST_FOREACH(BlockMap::value_type& entry, mapBlockIndex) {
delete entry.second;
......
......@@ -576,6 +576,11 @@ extern CBlockTreeDB *pblocktree;
*/
int GetSpendHeight(const CCoinsViewCache& inputs);
/**
* Determine what nVersion a new block should use.
*/
int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params);
/** Reject codes greater or equal to this can be returned by AcceptToMemPool
* for transactions, to signal internal conditions. They cannot and should not
* be sent over the P2P network.
......
......@@ -120,14 +120,15 @@ CBlockTemplate* CreateNewBlock(const CChainParams& chainparams, const CScript& s
pblock->nTime = GetAdjustedTime();
const int64_t nMedianTimePast = pindexPrev->GetMedianTimePast();
pblock->nVersion = BASE_VERSION;
pblock->nVersion = ComputeBlockVersion(pindexPrev, chainparams.GetConsensus());
// Vote for 2 MB until the vote expiration time
if (pblock->nTime <= chainparams.GetConsensus().SizeForkExpiration())
pblock->nVersion |= FORK_BIT_2MB;
// -regtest only: allow overriding block.nVersion with
// -blockversion=N to test forking scenarios
if (Params().MineBlocksOnDemand())
if (chainparams.MineBlocksOnDemand())
pblock->nVersion = GetArg("-blockversion", pblock->nVersion);
UpdateTime(pblock, Params().GetConsensus(), pindexPrev);
......
......@@ -55,7 +55,7 @@ public:
void SetNull()
{
nVersion = CBlockHeader::CURRENT_VERSION;
nVersion = 0;
hashPrevBlock.SetNull();
hashMerkleRoot.SetNull();
nTime = 0;
......
......@@ -258,13 +258,40 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
// subsidy changing
int nHeight = chainActive.Height();
chainActive.Tip()->nHeight = 209999;
// Create an actual 209999-long block chain (without valid blocks).
while (chainActive.Tip()->nHeight < 209999) {
CBlockIndex* prev = chainActive.Tip();
CBlockIndex* next = new CBlockIndex();
next->phashBlock = new uint256(GetRandHash());
pcoinsTip->SetBestBlock(next->GetBlockHash());
next->pprev = prev;
next->nHeight = prev->nHeight + 1;
next->BuildSkip();
chainActive.SetTip(next);
}
BOOST_CHECK(pblocktemplate = CreateNewBlock(chainparams, scriptPubKey));
delete pblocktemplate;
chainActive.Tip()->nHeight = 210000;
// Extend to a 210000-long block chain.
while (chainActive.Tip()->nHeight < 210000) {
CBlockIndex* prev = chainActive.Tip();
CBlockIndex* next = new CBlockIndex();
next->phashBlock = new uint256(GetRandHash());
pcoinsTip->SetBestBlock(next->GetBlockHash());
next->pprev = prev;
next->nHeight = prev->nHeight + 1;
next->BuildSkip();
chainActive.SetTip(next);
}
BOOST_CHECK(pblocktemplate = CreateNewBlock(chainparams, scriptPubKey));
delete pblocktemplate;
chainActive.Tip()->nHeight = nHeight;
// Delete the dummy blocks again.
while (chainActive.Tip()->nHeight > nHeight) {
CBlockIndex* del = chainActive.Tip();
chainActive.SetTip(del->pprev);
pcoinsTip->SetBestBlock(del->pprev->GetBlockHash());
delete del->phashBlock;
delete del;
}
// non-final txs in mempool
SetMockTime(chainActive.Tip()->GetMedianTimePast()+1);
......
// Copyright (c) 2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "versionbits.h"
ThresholdState AbstractThresholdConditionChecker::GetStateFor(const CBlockIndex* pindexPrev, const Consensus::Params& params, ThresholdConditionCache& cache) const
{
int nPeriod = Period(params);
int nThreshold = Threshold(params);
int64_t nTimeStart = BeginTime(params);
int64_t nTimeTimeout = EndTime(params);
// A block's state is always the same as that of the first of its period, so it is computed based on a pindexPrev whose height equals a multiple of nPeriod - 1.
if (pindexPrev != NULL) {
pindexPrev = pindexPrev->GetAncestor(pindexPrev->nHeight - ((pindexPrev->nHeight + 1) % nPeriod));
}
// Walk backwards in steps of nPeriod to find a pindexPrev whose information is known
std::vector<const CBlockIndex*> vToCompute;
while (cache.count(pindexPrev) == 0) {
if (pindexPrev == NULL) {
// The genesis block is by definition defined.
cache[pindexPrev] = THRESHOLD_DEFINED;
break;
}
if (pindexPrev->GetMedianTimePast() < nTimeStart) {
// Optimizaton: don't recompute down further, as we know every earlier block will be before the start time
cache[pindexPrev] = THRESHOLD_DEFINED;
break;
}
vToCompute.push_back(pindexPrev);
pindexPrev = pindexPrev->GetAncestor(pindexPrev->nHeight - nPeriod);
}
// At this point, cache[pindexPrev] is known
assert(cache.count(pindexPrev));
ThresholdState state = cache[pindexPrev];
// Now walk forward and compute the state of descendants of pindexPrev
while (!vToCompute.empty()) {
ThresholdState stateNext = state;
pindexPrev = vToCompute.back();
vToCompute.pop_back();
switch (state) {
case THRESHOLD_DEFINED: {
if (pindexPrev->GetMedianTimePast() >= nTimeTimeout) {
stateNext = THRESHOLD_FAILED;
} else if (pindexPrev->GetMedianTimePast() >= nTimeStart) {
stateNext = THRESHOLD_STARTED;
}
break;
}
case THRESHOLD_STARTED: {
if (pindexPrev->GetMedianTimePast() >= nTimeTimeout) {
stateNext = THRESHOLD_FAILED;
break;
}
// We need to count
const CBlockIndex* pindexCount = pindexPrev;
int count = 0;
for (int i = 0; i < nPeriod; i++) {
if (Condition(pindexCount, params)) {
count++;
}
pindexCount = pindexCount->pprev;
}
if (count >= nThreshold) {
stateNext = THRESHOLD_LOCKED_IN;
}
break;
}
case THRESHOLD_LOCKED_IN: {
// Always progresses into ACTIVE.
stateNext = THRESHOLD_ACTIVE;
break;
}
case THRESHOLD_FAILED:
case THRESHOLD_ACTIVE: {
// Nothing happens, these are terminal states.
break;
}
}
cache[pindexPrev] = state = stateNext;
}
return state;
}
namespace
{
/**
* Class to implement versionbits logic.
*/
class VersionBitsConditionChecker : public AbstractThresholdConditionChecker {
private:
const Consensus::DeploymentPos id;
protected:
int64_t BeginTime(const Consensus::Params& params) const { return params.vDeployments[id].nStartTime; }
int64_t EndTime(const Consensus::Params& params) const { return params.vDeployments[id].nTimeout; }
int Period(const Consensus::Params& params) const { return params.nMinerConfirmationWindow; }
int Threshold(const Consensus::Params& params) const { return params.nRuleChangeActivationThreshold; }
bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const
{
return (((pindex->nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS) && (pindex->nVersion & Mask(params)) != 0);
}
public:
VersionBitsConditionChecker(Consensus::DeploymentPos id_) : id(id_) {}
uint32_t Mask(const Consensus::Params& params) const { return ((uint32_t)1) << params.vDeployments[id].bit; }
};
}
ThresholdState VersionBitsState(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos, VersionBitsCache& cache)
{
return VersionBitsConditionChecker(pos).GetStateFor(pindexPrev, params, cache.caches[pos]);
}
uint32_t VersionBitsMask(const Consensus::Params& params, Consensus::DeploymentPos pos)
{
return VersionBitsConditionChecker(pos).Mask(params);
}
void VersionBitsCache::Clear()
{
for (unsigned int d = 0; d < Consensus::MAX_VERSION_BITS_DEPLOYMENTS; d++) {
caches[d].clear();
}
}
// Copyright (c) 2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_CONSENSUS_VERSIONBITS
#define BITCOIN_CONSENSUS_VERSIONBITS
#include "chain.h"
#include <map>
/** What block version to use for new blocks (pre versionbits) */
static const int32_t VERSIONBITS_LAST_OLD_BLOCK_VERSION = 4;
/** What bits to set in version for versionbits blocks */
static const int32_t VERSIONBITS_TOP_BITS = 0x20000000UL;
/** What bitmask determines whether versionbits is in use */
static const int32_t VERSIONBITS_TOP_MASK = 0xE0000000UL;
/** Total bits available for versionbits */
static const int32_t VERSIONBITS_NUM_BITS = 29;
enum ThresholdState {
THRESHOLD_DEFINED,
THRESHOLD_STARTED,
THRESHOLD_LOCKED_IN,
THRESHOLD_ACTIVE,
THRESHOLD_FAILED,
};
// A map that gives the state for blocks whose height is a multiple of Period().
// The map is indexed by the block's parent, however, so all keys in the map
// will either be NULL or a block with (height + 1) % Period() == 0.
typedef std::map<const CBlockIndex*, ThresholdState> ThresholdConditionCache;
/**
* Abstract class that implements BIP9-style threshold logic, and caches results.
*/
class AbstractThresholdConditionChecker {
protected:
virtual bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const =0;
virtual int64_t BeginTime(const Consensus::Params& params) const =0;
virtual int64_t EndTime(const Consensus::Params& params) const =0;
virtual int Period(const Consensus::Params& params) const =0;
virtual int Threshold(const Consensus::Params& params) const =0;
public:
// Note that the function below takes a pindexPrev as input: they compute information for block B based on its parent.
ThresholdState GetStateFor(const CBlockIndex* pindexPrev, const Consensus::Params& params, ThresholdConditionCache& cache) const;
};
struct VersionBitsCache
{
ThresholdConditionCache caches[Consensus::MAX_VERSION_BITS_DEPLOYMENTS];
void Clear();
};
ThresholdState VersionBitsState(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos, VersionBitsCache& cache);
uint32_t VersionBitsMask(const Consensus::Params& params, Consensus::DeploymentPos pos);
#endif
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