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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 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_PARAMS_H
#define BITCOIN_CONSENSUS_PARAMS_H
#include <uint256.h>
#include <array>
#include <chrono>
#include <limits>
#include <map>
#include <vector>
namespace Consensus {
/**
* A buried deployment is one where the height of the activation has been hardcoded into
* the client implementation long after the consensus change has activated. See BIP 90.
*/
enum BuriedDeployment : int16_t {
// buried deployments get negative values to avoid overlap with DeploymentPos
DEPLOYMENT_HEIGHTINCB = std::numeric_limits<int16_t>::min(),
DEPLOYMENT_CLTV,
DEPLOYMENT_DERSIG,
DEPLOYMENT_CSV,
DEPLOYMENT_SEGWIT,
};
constexpr bool ValidDeployment(BuriedDeployment dep) { return dep <= DEPLOYMENT_SEGWIT; }
enum DeploymentPos : uint16_t {
DEPLOYMENT_TESTDUMMY,
DEPLOYMENT_TAPROOT, // Deployment of Schnorr/Taproot (BIPs 340-342)
// NOTE: Also add new deployments to VersionBitsDeploymentInfo in deploymentinfo.cpp
DEPLOYMENT_CTV, // Deployment of CHECKTEMPLATEVERIFY (BIP 119) (regtest only)
MAX_VERSION_BITS_DEPLOYMENTS
};
constexpr bool ValidDeployment(DeploymentPos dep) { return dep < MAX_VERSION_BITS_DEPLOYMENTS; }
/**
* Struct for each individual consensus rule change using BIP9.
*/
struct BIP9Deployment {
/** Bit position to select the particular bit in nVersion. */
int bit{28};
/** Start MedianTime for version bits miner confirmation. Can be a date in the past */
int64_t nStartTime{NEVER_ACTIVE};
/** Timeout/expiry MedianTime for the deployment attempt. */
int64_t nTimeout{NEVER_ACTIVE};
/** If lock in occurs, delay activation until at least this block
* height. Note that activation will only occur on a retarget
* boundary.
*/
int min_activation_height{0};
/** Period of blocks to check signalling in (usually retarget period, ie params.DifficultyAdjustmentInterval()) */
uint32_t period{2016};
/**
* Minimum blocks including miner confirmation of the total of 2016 blocks in a retargeting period,
* which is also used for BIP9 deployments.
* Examples: 1916 for 95%, 1512 for testchains.
*/
uint32_t threshold{1916};
/** Constant for nTimeout very far in the future. */
static constexpr int64_t NO_TIMEOUT = std::numeric_limits<int64_t>::max();
/** Special value for nStartTime indicating that the deployment is always active.
* This is useful for testing, as it means tests don't need to deal with the activation
* process (which takes at least 3 BIP9 intervals). Only tests that specifically test the
* behaviour during activation cannot use this. */
static constexpr int64_t ALWAYS_ACTIVE = -1;
/** Special value for nStartTime indicating that the deployment is never active.
* This is useful for integrating the code changes for a new feature
* prior to deploying it on some or all networks. */
static constexpr int64_t NEVER_ACTIVE = -2;
};
/**
* Parameters that influence chain consensus.
*/
struct Params {
uint256 hashGenesisBlock;
int nSubsidyHalvingInterval;
/**
* Hashes of blocks that
* - are known to be consensus valid, and
* - buried in the chain, and
* - fail if the default script verify flags are applied.
*/
std::map<uint256, uint32_t> script_flag_exceptions;
/** Block height and hash at which BIP34 becomes active */
int BIP34Height;
uint256 BIP34Hash;
/** Block height at which BIP65 becomes active */
int BIP65Height;
/** Block height at which BIP66 becomes active */
int BIP66Height;
/** Block height at which CSV (BIP68, BIP112 and BIP113) becomes active */
int CSVHeight;
/** Block height at which Segwit (BIP141, BIP143 and BIP147) becomes active.
* Note that segwit v0 script rules are enforced on all blocks except the
* BIP 16 exception blocks. */
int SegwitHeight;
/** Don't warn about unknown BIP 9 activations below this height.
* This prevents us from warning about the CSV and segwit activations. */
int MinBIP9WarningHeight;
std::array<BIP9Deployment,MAX_VERSION_BITS_DEPLOYMENTS> vDeployments;
/** Proof of work parameters */
uint256 powLimit;
bool fPowAllowMinDifficultyBlocks;
/**
* Enforce BIP94 timewarp attack mitigation. On testnet4 this also enforces
* the block storm mitigation.
*/
bool enforce_BIP94;
bool fPowNoRetargeting;
int64_t nPowTargetSpacing;
int64_t nPowTargetTimespan;
std::chrono::seconds PowTargetSpacing() const
{
return std::chrono::seconds{nPowTargetSpacing};
}
int64_t DifficultyAdjustmentInterval() const { return nPowTargetTimespan / nPowTargetSpacing; }
/** The best chain should have at least this much work */
uint256 nMinimumChainWork;
/** By default assume that the signatures in ancestors of this block are valid */
uint256 defaultAssumeValid;
/**
* If true, witness commitments contain a payload equal to a Bitcoin Script solution
* to the signet challenge. See BIP325.
*/
bool signet_blocks{false};
std::vector<uint8_t> signet_challenge;
int DeploymentHeight(BuriedDeployment dep) const
{
switch (dep) {
case DEPLOYMENT_HEIGHTINCB:
return BIP34Height;
case DEPLOYMENT_CLTV:
return BIP65Height;
case DEPLOYMENT_DERSIG:
return BIP66Height;
case DEPLOYMENT_CSV:
return CSVHeight;
case DEPLOYMENT_SEGWIT:
return SegwitHeight;
} // no default case, so the compiler can warn about missing cases
return std::numeric_limits<int>::max();
}
};
} // namespace Consensus
#endif // BITCOIN_CONSENSUS_PARAMS_H