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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_POLICY_POLICY_H
7 : : #define BITCOIN_POLICY_POLICY_H
8 : :
9 : : #include <consensus/amount.h>
10 : : #include <consensus/consensus.h>
11 : : #include <primitives/transaction.h>
12 : : #include <script/interpreter.h>
13 : : #include <script/solver.h>
14 : :
15 : : #include <cstdint>
16 : : #include <string>
17 : :
18 : : class CCoinsViewCache;
19 : : class CFeeRate;
20 : : class CScript;
21 : :
22 : : /** Default for -blockmaxweight, which controls the range of block weights the mining code will create **/
23 : : static constexpr unsigned int DEFAULT_BLOCK_MAX_WEIGHT{MAX_BLOCK_WEIGHT};
24 : : /** Default for -blockreservedweight **/
25 : : static constexpr unsigned int DEFAULT_BLOCK_RESERVED_WEIGHT{8000};
26 : : /** This accounts for the block header, var_int encoding of the transaction count and a minimally viable
27 : : * coinbase transaction. It adds an additional safety margin, because even with a thorough understanding
28 : : * of block serialization, it's easy to make a costly mistake when trying to squeeze every last byte.
29 : : * Setting a lower value is prevented at startup. */
30 : : static constexpr unsigned int MINIMUM_BLOCK_RESERVED_WEIGHT{2000};
31 : : /** Default for -blockmintxfee, which sets the minimum feerate for a transaction in blocks created by mining code **/
32 : : static constexpr unsigned int DEFAULT_BLOCK_MIN_TX_FEE{1000};
33 : : /** The maximum weight for transactions we're willing to relay/mine */
34 : : static constexpr int32_t MAX_STANDARD_TX_WEIGHT{400000};
35 : : /** The minimum non-witness size for transactions we're willing to relay/mine: one larger than 64 */
36 : : static constexpr unsigned int MIN_STANDARD_TX_NONWITNESS_SIZE{65};
37 : : /** Maximum number of signature check operations in an IsStandard() P2SH script */
38 : : static constexpr unsigned int MAX_P2SH_SIGOPS{15};
39 : : /** The maximum number of sigops we're willing to relay/mine in a single tx */
40 : : static constexpr unsigned int MAX_STANDARD_TX_SIGOPS_COST{MAX_BLOCK_SIGOPS_COST/5};
41 : : /** Default for -incrementalrelayfee, which sets the minimum feerate increase for mempool limiting or replacement **/
42 : : static constexpr unsigned int DEFAULT_INCREMENTAL_RELAY_FEE{1000};
43 : : /** Default for -bytespersigop */
44 : : static constexpr unsigned int DEFAULT_BYTES_PER_SIGOP{20};
45 : : /** Default for -permitbaremultisig */
46 : : static constexpr bool DEFAULT_PERMIT_BAREMULTISIG{true};
47 : : /** The maximum number of witness stack items in a standard P2WSH script */
48 : : static constexpr unsigned int MAX_STANDARD_P2WSH_STACK_ITEMS{100};
49 : : /** The maximum size in bytes of each witness stack item in a standard P2WSH script */
50 : : static constexpr unsigned int MAX_STANDARD_P2WSH_STACK_ITEM_SIZE{80};
51 : : /** The maximum size in bytes of each witness stack item in a standard BIP 342 script (Taproot, leaf version 0xc0) */
52 : : static constexpr unsigned int MAX_STANDARD_TAPSCRIPT_STACK_ITEM_SIZE{80};
53 : : /** The maximum size in bytes of a standard witnessScript */
54 : : static constexpr unsigned int MAX_STANDARD_P2WSH_SCRIPT_SIZE{3600};
55 : : /** The maximum size of a standard ScriptSig */
56 : : static constexpr unsigned int MAX_STANDARD_SCRIPTSIG_SIZE{1650};
57 : : /** Min feerate for defining dust.
58 : : * Changing the dust limit changes which transactions are
59 : : * standard and should be done with care and ideally rarely. It makes sense to
60 : : * only increase the dust limit after prior releases were already not creating
61 : : * outputs below the new threshold */
62 : : static constexpr unsigned int DUST_RELAY_TX_FEE{3000};
63 : : /** Default for -minrelaytxfee, minimum relay fee for transactions */
64 : : static constexpr unsigned int DEFAULT_MIN_RELAY_TX_FEE{1000};
65 : : /** Default for -limitancestorcount, max number of in-mempool ancestors */
66 : : static constexpr unsigned int DEFAULT_ANCESTOR_LIMIT{25};
67 : : /** Default for -limitancestorsize, maximum kilobytes of tx + all in-mempool ancestors */
68 : : static constexpr unsigned int DEFAULT_ANCESTOR_SIZE_LIMIT_KVB{101};
69 : : /** Default for -limitdescendantcount, max number of in-mempool descendants */
70 : : static constexpr unsigned int DEFAULT_DESCENDANT_LIMIT{25};
71 : : /** Default for -limitdescendantsize, maximum kilobytes of in-mempool descendants */
72 : : static constexpr unsigned int DEFAULT_DESCENDANT_SIZE_LIMIT_KVB{101};
73 : : /** Default for -datacarrier */
74 : : static const bool DEFAULT_ACCEPT_DATACARRIER = true;
75 : : /**
76 : : * Default setting for -datacarriersize. 80 bytes of data, +1 for OP_RETURN,
77 : : * +2 for the pushdata opcodes.
78 : : */
79 : : static const unsigned int MAX_OP_RETURN_RELAY = 83;
80 : : /**
81 : : * An extra transaction can be added to a package, as long as it only has one
82 : : * ancestor and is no larger than this. Not really any reason to make this
83 : : * configurable as it doesn't materially change DoS parameters.
84 : : */
85 : : static constexpr unsigned int EXTRA_DESCENDANT_TX_SIZE_LIMIT{10000};
86 : :
87 : : /**
88 : : * Maximum number of ephemeral dust outputs allowed.
89 : : */
90 : : static constexpr unsigned int MAX_DUST_OUTPUTS_PER_TX{1};
91 : :
92 : : /**
93 : : * Mandatory script verification flags that all new transactions must comply with for
94 : : * them to be valid. Failing one of these tests may trigger a DoS ban;
95 : : * see CheckInputScripts() for details.
96 : : *
97 : : * Note that this does not affect consensus validity; see GetBlockScriptFlags()
98 : : * for that.
99 : : */
100 : : static constexpr unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS{SCRIPT_VERIFY_P2SH |
101 : : SCRIPT_VERIFY_DERSIG |
102 : : SCRIPT_VERIFY_NULLDUMMY |
103 : : SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY |
104 : : SCRIPT_VERIFY_CHECKSEQUENCEVERIFY |
105 : : SCRIPT_VERIFY_WITNESS |
106 : : SCRIPT_VERIFY_TAPROOT};
107 : :
108 : : /**
109 : : * Standard script verification flags that standard transactions will comply
110 : : * with. However we do not ban/disconnect nodes that forward txs violating
111 : : * the additional (non-mandatory) rules here, to improve forwards and
112 : : * backwards compatibility.
113 : : */
114 : : static constexpr unsigned int STANDARD_SCRIPT_VERIFY_FLAGS{MANDATORY_SCRIPT_VERIFY_FLAGS |
115 : : SCRIPT_VERIFY_STRICTENC |
116 : : SCRIPT_VERIFY_MINIMALDATA |
117 : : SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS |
118 : : SCRIPT_VERIFY_CLEANSTACK |
119 : : SCRIPT_VERIFY_MINIMALIF |
120 : : SCRIPT_VERIFY_NULLFAIL |
121 : : SCRIPT_VERIFY_LOW_S |
122 : : SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM |
123 : : SCRIPT_VERIFY_WITNESS_PUBKEYTYPE |
124 : : SCRIPT_VERIFY_CONST_SCRIPTCODE |
125 : : SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_TAPROOT_VERSION |
126 : : SCRIPT_VERIFY_DISCOURAGE_OP_SUCCESS |
127 : : SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE};
128 : :
129 : : /** For convenience, standard but not mandatory verify flags. */
130 : : static constexpr unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS{STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS};
131 : :
132 : : /** Used as the flags parameter to sequence and nLocktime checks in non-consensus code. */
133 : : static constexpr unsigned int STANDARD_LOCKTIME_VERIFY_FLAGS{LOCKTIME_VERIFY_SEQUENCE};
134 : :
135 : : CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFee);
136 : :
137 : : bool IsDust(const CTxOut& txout, const CFeeRate& dustRelayFee);
138 : :
139 : : bool IsStandard(const CScript& scriptPubKey, const std::optional<unsigned>& max_datacarrier_bytes, TxoutType& whichType);
140 : :
141 : : /** Get the vout index numbers of all dust outputs */
142 : : std::vector<uint32_t> GetDust(const CTransaction& tx, CFeeRate dust_relay_rate);
143 : :
144 : : // Changing the default transaction version requires a two step process: first
145 : : // adapting relay policy by bumping TX_MAX_STANDARD_VERSION, and then later
146 : : // allowing the new transaction version in the wallet/RPC.
147 : : static constexpr decltype(CTransaction::version) TX_MAX_STANDARD_VERSION{3};
148 : :
149 : : /**
150 : : * Check for standard transaction types
151 : : * @return True if all outputs (scriptPubKeys) use only standard transaction forms
152 : : */
153 : : bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_datacarrier_bytes, bool permit_bare_multisig, const CFeeRate& dust_relay_fee, std::string& reason);
154 : : /**
155 : : * Check for standard transaction types
156 : : * @param[in] mapInputs Map of previous transactions that have outputs we're spending
157 : : * @return True if all inputs (scriptSigs) use only standard transaction forms
158 : : */
159 : : bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs);
160 : : /**
161 : : * Check if the transaction is over standard P2WSH resources limit:
162 : : * 3600bytes witnessScript size, 80bytes per witness stack element, 100 witness stack elements
163 : : * These limits are adequate for multisignatures up to n-of-100 using OP_CHECKSIG, OP_ADD, and OP_EQUAL.
164 : : *
165 : : * Also enforce a maximum stack item size limit and no annexes for tapscript spends.
166 : : */
167 : : bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs);
168 : :
169 : : /** Compute the virtual transaction size (weight reinterpreted as bytes). */
170 : : int64_t GetVirtualTransactionSize(int64_t nWeight, int64_t nSigOpCost, unsigned int bytes_per_sigop);
171 : : int64_t GetVirtualTransactionSize(const CTransaction& tx, int64_t nSigOpCost, unsigned int bytes_per_sigop);
172 : : int64_t GetVirtualTransactionInputSize(const CTxIn& tx, int64_t nSigOpCost, unsigned int bytes_per_sigop);
173 : :
174 : 55832 : static inline int64_t GetVirtualTransactionSize(const CTransaction& tx)
175 : : {
176 [ + - + - : 55826 : return GetVirtualTransactionSize(tx, 0, 0);
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177 : : }
178 : :
179 : 2 : static inline int64_t GetVirtualTransactionInputSize(const CTxIn& tx)
180 : : {
181 [ + - ]: 2 : return GetVirtualTransactionInputSize(tx, 0, 0);
182 : : }
183 : :
184 : : #endif // BITCOIN_POLICY_POLICY_H
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