1 // Copyright (c) 2009-2010 Satoshi Nakamoto
2 // Copyright (c) 2009-present 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_VALIDATION_H
7 #define BITCOIN_CONSENSUS_VALIDATION_H
8 9 #include <string>
10 #include <consensus/consensus.h>
11 #include <primitives/transaction.h>
12 #include <primitives/block.h>
13 14 /** Index marker for when no witness commitment is present in a coinbase transaction. */
15 static constexpr int NO_WITNESS_COMMITMENT{-1};
16 17 /** Minimum size of a witness commitment structure. Defined in BIP 141. **/
18 static constexpr size_t MINIMUM_WITNESS_COMMITMENT{38};
19 20 /** A "reason" why a transaction was invalid, suitable for determining whether the
21 * provider of the transaction should be banned/ignored/disconnected/etc.
22 */
23 enum class TxValidationResult {
24 TX_RESULT_UNSET = 0, //!< initial value. Tx has not yet been rejected
25 TX_CONSENSUS, //!< invalid by consensus rules
26 TX_INPUTS_NOT_STANDARD, //!< inputs (covered by txid) failed policy rules
27 TX_NOT_STANDARD, //!< otherwise didn't meet our local policy rules
28 TX_MISSING_INPUTS, //!< transaction was missing some of its inputs
29 TX_PREMATURE_SPEND, //!< transaction spends a coinbase too early, or violates locktime/sequence locks
30 /**
31 * Transaction might have a witness prior to SegWit
32 * activation, or witness may have been malleated (which includes
33 * non-standard witnesses).
34 */
35 TX_WITNESS_MUTATED,
36 /**
37 * Transaction is missing a witness.
38 */
39 TX_WITNESS_STRIPPED,
40 /**
41 * Tx already in mempool or conflicts with a tx in the chain
42 * (if it conflicts with another tx in mempool, we use MEMPOOL_POLICY as it failed to reach the RBF threshold)
43 * Currently this is only used if the transaction already exists in the mempool or on chain.
44 */
45 TX_CONFLICT,
46 TX_MEMPOOL_POLICY, //!< violated mempool's fee/size/descendant/RBF/etc limits
47 TX_NO_MEMPOOL, //!< this node does not have a mempool so can't validate the transaction
48 TX_RECONSIDERABLE, //!< fails some policy, but might be acceptable if submitted in a (different) package
49 TX_UNKNOWN, //!< transaction was not validated because package failed
50 };
51 52 /** A "reason" why a block was invalid, suitable for determining whether the
53 * provider of the block should be banned/ignored/disconnected/etc.
54 * These are much more granular than the rejection codes, which may be more
55 * useful for some other use-cases.
56 */
57 enum class BlockValidationResult {
58 BLOCK_RESULT_UNSET = 0, //!< initial value. Block has not yet been rejected
59 BLOCK_CONSENSUS, //!< invalid by consensus rules (excluding any below reasons)
60 BLOCK_CACHED_INVALID, //!< this block was cached as being invalid and we didn't store the reason why
61 BLOCK_INVALID_HEADER, //!< invalid proof of work or time too old
62 BLOCK_MUTATED, //!< the block's data didn't match the data committed to by the PoW
63 BLOCK_MISSING_PREV, //!< We don't have the previous block the checked one is built on
64 BLOCK_INVALID_PREV, //!< A block this one builds on is invalid
65 BLOCK_TIME_FUTURE, //!< block timestamp was > 2 hours in the future (or our clock is bad)
66 BLOCK_HEADER_LOW_WORK //!< the block header may be on a too-little-work chain
67 };
68 69 70 71 /** Template for capturing information about block/transaction validation. This is instantiated
72 * by TxValidationState and BlockValidationState for validation information on transactions
73 * and blocks respectively. */
74 template <typename Result>
75 class ValidationState
76 {
77 private:
78 enum class ModeState {
79 M_VALID, //!< everything ok
80 M_INVALID, //!< network rule violation (DoS value may be set)
81 M_ERROR, //!< run-time error
82 } m_mode{ModeState::M_VALID};
83 Result m_result{};
84 std::string m_reject_reason;
85 std::string m_debug_message;
86 87 public:
88 bool Invalid(Result result,
89 const std::string& reject_reason = "",
90 const std::string& debug_message = "")
91 {
92 m_result = result;
93 m_reject_reason = reject_reason;
94 m_debug_message = debug_message;
95 if (m_mode != ModeState::M_ERROR) m_mode = ModeState::M_INVALID;
96 return false;
97 }
98 bool Error(const std::string& reject_reason)
99 {
100 if (m_mode == ModeState::M_VALID)
101 m_reject_reason = reject_reason;
102 m_mode = ModeState::M_ERROR;
103 return false;
104 }
105 bool IsValid() const { return m_mode == ModeState::M_VALID; }
106 bool IsInvalid() const { return m_mode == ModeState::M_INVALID; }
107 bool IsError() const { return m_mode == ModeState::M_ERROR; }
108 Result GetResult() const { return m_result; }
109 std::string GetRejectReason() const { return m_reject_reason; }
110 std::string GetDebugMessage() const { return m_debug_message; }
111 std::string ToString() const
112 {
113 if (IsValid()) {
114 return "Valid";
115 }
116 117 if (!m_debug_message.empty()) {
118 return m_reject_reason + ", " + m_debug_message;
119 }
120 121 return m_reject_reason;
122 }
123 };
124 125 class TxValidationState : public ValidationState<TxValidationResult> {};
126 class BlockValidationState : public ValidationState<BlockValidationResult> {};
127 128 // These implement the weight = (stripped_size * 4) + witness_size formula,
129 // using only serialization with and without witness data. As witness_size
130 // is equal to total_size - stripped_size, this formula is identical to:
131 // weight = (stripped_size * 3) + total_size.
132 static inline int32_t GetTransactionWeight(const CTransaction& tx)
133 {
134 return ::GetSerializeSize(TX_NO_WITNESS(tx)) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(TX_WITH_WITNESS(tx));
135 }
136 static inline int64_t GetBlockWeight(const CBlock& block)
137 {
138 return ::GetSerializeSize(TX_NO_WITNESS(block)) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(TX_WITH_WITNESS(block));
139 }
140 static inline int64_t GetTransactionInputWeight(const CTxIn& txin)
141 {
142 // scriptWitness size is added here because witnesses and txins are split up in segwit serialization.
143 return ::GetSerializeSize(TX_NO_WITNESS(txin)) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(TX_WITH_WITNESS(txin)) + ::GetSerializeSize(txin.scriptWitness.stack);
144 }
145 146 /** Compute at which vout of the block's coinbase transaction the witness commitment occurs, or -1 if not found */
147 inline int GetWitnessCommitmentIndex(const CBlock& block)
148 {
149 int commitpos = NO_WITNESS_COMMITMENT;
150 if (!block.vtx.empty()) {
151 for (size_t o = 0; o < block.vtx[0]->vout.size(); o++) {
152 const CTxOut& vout = block.vtx[0]->vout[o];
153 if (vout.scriptPubKey.size() >= MINIMUM_WITNESS_COMMITMENT &&
154 vout.scriptPubKey[0] == OP_RETURN &&
155 vout.scriptPubKey[1] == 0x24 &&
156 vout.scriptPubKey[2] == 0xaa &&
157 vout.scriptPubKey[3] == 0x21 &&
158 vout.scriptPubKey[4] == 0xa9 &&
159 vout.scriptPubKey[5] == 0xed) {
160 commitpos = o;
161 }
162 }
163 }
164 return commitpos;
165 }
166 167 #endif // BITCOIN_CONSENSUS_VALIDATION_H
168