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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 : : 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 : : 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 : : struct BIP9Deployment {
44 : : /** Bit position to select the particular bit in nVersion. */
45 : : int bit{28};
46 : : /** Start MedianTime for version bits miner confirmation. Can be a date in the past */
47 : : int64_t nStartTime{NEVER_ACTIVE};
48 : : /** Timeout/expiry MedianTime for the deployment attempt. */
49 : : 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 : : 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 : : 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 : : /**
112 : : * Enforce BIP94 timewarp attack mitigation. On testnet4 this also enforces
113 : : * the block storm mitigation.
114 : : */
115 : : bool enforce_BIP94;
116 : : bool fPowNoRetargeting;
117 : : int64_t nPowTargetSpacing;
118 : : int64_t nPowTargetTimespan;
119 : 77046 : std::chrono::seconds PowTargetSpacing() const
120 : : {
121 : 77046 : return std::chrono::seconds{nPowTargetSpacing};
122 : : }
123 [ + - + + ]: 272074 : int64_t DifficultyAdjustmentInterval() const { return nPowTargetTimespan / nPowTargetSpacing; }
[ + + # # ]
124 : : /** The best chain should have at least this much work */
125 : : uint256 nMinimumChainWork;
126 : : /** By default assume that the signatures in ancestors of this block are valid */
127 : : uint256 defaultAssumeValid;
128 : :
129 : : /**
130 : : * If true, witness commitments contain a payload equal to a Bitcoin Script solution
131 : : * to the signet challenge. See BIP325.
132 : : */
133 : : bool signet_blocks{false};
134 : : std::vector<uint8_t> signet_challenge;
135 : :
136 : 1940761 : int DeploymentHeight(BuriedDeployment dep) const
137 : : {
138 [ + + + + : 1940761 : switch (dep) {
+ - ]
139 : 168313 : case DEPLOYMENT_HEIGHTINCB:
140 : 168313 : return BIP34Height;
141 : 198856 : case DEPLOYMENT_CLTV:
142 : 198856 : return BIP65Height;
143 : 198855 : case DEPLOYMENT_DERSIG:
144 : 198855 : return BIP66Height;
145 : 537432 : case DEPLOYMENT_CSV:
146 : 537432 : return CSVHeight;
147 : 837305 : case DEPLOYMENT_SEGWIT:
148 : 837305 : return SegwitHeight;
149 : : } // no default case, so the compiler can warn about missing cases
150 : : return std::numeric_limits<int>::max();
151 : : }
152 : : };
153 : :
154 : : } // namespace Consensus
155 : :
156 : : #endif // BITCOIN_CONSENSUS_PARAMS_H
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