Line data    Source code

       1             : // Copyright (c) 2009-2010 Satoshi Nakamoto
       2             : // Copyright (c) 2009-2022 The Bitcoin Core developers
       3             : // Distributed under the MIT software license, see the accompanying
       4             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       5             : 
       6             : #ifndef BITCOIN_CONSENSUS_PARAMS_H
       7             : #define BITCOIN_CONSENSUS_PARAMS_H
       8             : 
       9             : #include <uint256.h>
      10             : 
      11             : #include <chrono>
      12             : #include <limits>
      13             : #include <map>
      14             : #include <vector>
      15             : 
      16             : namespace Consensus {
      17             : 
      18             : /**
      19             :  * A buried deployment is one where the height of the activation has been hardcoded into
      20             :  * the client implementation long after the consensus change has activated. See BIP 90.
      21             :  */
      22             : enum BuriedDeployment : int16_t {
      23             :     // buried deployments get negative values to avoid overlap with DeploymentPos
      24             :     DEPLOYMENT_HEIGHTINCB = std::numeric_limits<int16_t>::min(),
      25             :     DEPLOYMENT_CLTV,
      26             :     DEPLOYMENT_DERSIG,
      27             :     DEPLOYMENT_CSV,
      28             :     DEPLOYMENT_SEGWIT,
      29             : };
      30       57552 : constexpr bool ValidDeployment(BuriedDeployment dep) { return dep <= DEPLOYMENT_SEGWIT; }
      31             : 
      32             : enum DeploymentPos : uint16_t {
      33             :     DEPLOYMENT_TESTDUMMY,
      34             :     DEPLOYMENT_TAPROOT, // Deployment of Schnorr/Taproot (BIPs 340-342)
      35             :     // NOTE: Also add new deployments to VersionBitsDeploymentInfo in deploymentinfo.cpp
      36             :     MAX_VERSION_BITS_DEPLOYMENTS
      37             : };
      38           0 : constexpr bool ValidDeployment(DeploymentPos dep) { return dep < MAX_VERSION_BITS_DEPLOYMENTS; }
      39             : 
      40             : /**
      41             :  * Struct for each individual consensus rule change using BIP9.
      42             :  */
      43         736 : struct BIP9Deployment {
      44             :     /** Bit position to select the particular bit in nVersion. */
      45         736 :     int bit{28};
      46             :     /** Start MedianTime for version bits miner confirmation. Can be a date in the past */
      47         736 :     int64_t nStartTime{NEVER_ACTIVE};
      48             :     /** Timeout/expiry MedianTime for the deployment attempt. */
      49         736 :     int64_t nTimeout{NEVER_ACTIVE};
      50             :     /** If lock in occurs, delay activation until at least this block
      51             :      *  height.  Note that activation will only occur on a retarget
      52             :      *  boundary.
      53             :      */
      54         736 :     int min_activation_height{0};
      55             : 
      56             :     /** Constant for nTimeout very far in the future. */
      57             :     static constexpr int64_t NO_TIMEOUT = std::numeric_limits<int64_t>::max();
      58             : 
      59             :     /** Special value for nStartTime indicating that the deployment is always active.
      60             :      *  This is useful for testing, as it means tests don't need to deal with the activation
      61             :      *  process (which takes at least 3 BIP9 intervals). Only tests that specifically test the
      62             :      *  behaviour during activation cannot use this. */
      63             :     static constexpr int64_t ALWAYS_ACTIVE = -1;
      64             : 
      65             :     /** Special value for nStartTime indicating that the deployment is never active.
      66             :      *  This is useful for integrating the code changes for a new feature
      67             :      *  prior to deploying it on some or all networks. */
      68             :     static constexpr int64_t NEVER_ACTIVE = -2;
      69             : };
      70             : 
      71             : /**
      72             :  * Parameters that influence chain consensus.
      73             :  */
      74         368 : struct Params {
      75             :     uint256 hashGenesisBlock;
      76             :     int nSubsidyHalvingInterval;
      77             :     /**
      78             :      * Hashes of blocks that
      79             :      * - are known to be consensus valid, and
      80             :      * - buried in the chain, and
      81             :      * - fail if the default script verify flags are applied.
      82             :      */
      83             :     std::map<uint256, uint32_t> script_flag_exceptions;
      84             :     /** Block height and hash at which BIP34 becomes active */
      85             :     int BIP34Height;
      86             :     uint256 BIP34Hash;
      87             :     /** Block height at which BIP65 becomes active */
      88             :     int BIP65Height;
      89             :     /** Block height at which BIP66 becomes active */
      90             :     int BIP66Height;
      91             :     /** Block height at which CSV (BIP68, BIP112 and BIP113) becomes active */
      92             :     int CSVHeight;
      93             :     /** Block height at which Segwit (BIP141, BIP143 and BIP147) becomes active.
      94             :      * Note that segwit v0 script rules are enforced on all blocks except the
      95             :      * BIP 16 exception blocks. */
      96             :     int SegwitHeight;
      97             :     /** Don't warn about unknown BIP 9 activations below this height.
      98             :      * This prevents us from warning about the CSV and segwit activations. */
      99             :     int MinBIP9WarningHeight;
     100             :     /**
     101             :      * Minimum blocks including miner confirmation of the total of 2016 blocks in a retargeting period,
     102             :      * (nPowTargetTimespan / nPowTargetSpacing) which is also used for BIP9 deployments.
     103             :      * Examples: 1916 for 95%, 1512 for testchains.
     104             :      */
     105             :     uint32_t nRuleChangeActivationThreshold;
     106             :     uint32_t nMinerConfirmationWindow;
     107             :     BIP9Deployment vDeployments[MAX_VERSION_BITS_DEPLOYMENTS];
     108             :     /** Proof of work parameters */
     109             :     uint256 powLimit;
     110             :     bool fPowAllowMinDifficultyBlocks;
     111             :     bool fPowNoRetargeting;
     112             :     int64_t nPowTargetSpacing;
     113             :     int64_t nPowTargetTimespan;
     114           0 :     std::chrono::seconds PowTargetSpacing() const
     115             :     {
     116           0 :         return std::chrono::seconds{nPowTargetSpacing};
     117             :     }
     118      125277 :     int64_t DifficultyAdjustmentInterval() const { return nPowTargetTimespan / nPowTargetSpacing; }
     119             :     /** The best chain should have at least this much work */
     120             :     uint256 nMinimumChainWork;
     121             :     /** By default assume that the signatures in ancestors of this block are valid */
     122             :     uint256 defaultAssumeValid;
     123             : 
     124             :     /**
     125             :      * If true, witness commitments contain a payload equal to a Bitcoin Script solution
     126             :      * to the signet challenge. See BIP325.
     127             :      */
     128         368 :     bool signet_blocks{false};
     129             :     std::vector<uint8_t> signet_challenge;
     130             : 
     131       57552 :     int DeploymentHeight(BuriedDeployment dep) const
     132             :     {
     133       57552 :         switch (dep) {
     134             :         case DEPLOYMENT_HEIGHTINCB:
     135        5259 :             return BIP34Height;
     136             :         case DEPLOYMENT_CLTV:
     137        7814 :             return BIP65Height;
     138             :         case DEPLOYMENT_DERSIG:
     139        7814 :             return BIP66Height;
     140             :         case DEPLOYMENT_CSV:
     141       18332 :             return CSVHeight;
     142             :         case DEPLOYMENT_SEGWIT:
     143       18333 :             return SegwitHeight;
     144             :         } // no default case, so the compiler can warn about missing cases
     145           0 :         return std::numeric_limits<int>::max();
     146       57552 :     }
     147             : };
     148             : 
     149             : } // namespace Consensus
     150             : 
     151             : #endif // BITCOIN_CONSENSUS_PARAMS_H