validation.h
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_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 /** 27 * Invalid by a change to consensus rules more recent than SegWit. 28 * Currently unused as there are no such consensus rule changes, and any download 29 * sources realistically need to support SegWit in order to provide useful data, 30 * so differentiating between always-invalid and invalid-by-pre-SegWit-soft-fork 31 * is uninteresting. 32 */ 33 TX_RECENT_CONSENSUS_CHANGE, 34 TX_INPUTS_NOT_STANDARD, //!< inputs (covered by txid) failed policy rules 35 TX_NOT_STANDARD, //!< otherwise didn't meet our local policy rules 36 TX_MISSING_INPUTS, //!< transaction was missing some of its inputs 37 TX_PREMATURE_SPEND, //!< transaction spends a coinbase too early, or violates locktime/sequence locks 38 /** 39 * Transaction might have a witness prior to SegWit 40 * activation, or witness may have been malleated (which includes 41 * non-standard witnesses). 42 */ 43 TX_WITNESS_MUTATED, 44 /** 45 * Transaction is missing a witness. 46 */ 47 TX_WITNESS_STRIPPED, 48 /** 49 * Tx already in mempool or conflicts with a tx in the chain 50 * (if it conflicts with another tx in mempool, we use MEMPOOL_POLICY as it failed to reach the RBF threshold) 51 * Currently this is only used if the transaction already exists in the mempool or on chain. 52 */ 53 TX_CONFLICT, 54 TX_MEMPOOL_POLICY, //!< violated mempool's fee/size/descendant/RBF/etc limits 55 TX_NO_MEMPOOL, //!< this node does not have a mempool so can't validate the transaction 56 TX_RECONSIDERABLE, //!< fails some policy, but might be acceptable if submitted in a (different) package 57 TX_UNKNOWN, //!< transaction was not validated because package failed 58 }; 59 60 /** A "reason" why a block was invalid, suitable for determining whether the 61 * provider of the block should be banned/ignored/disconnected/etc. 62 * These are much more granular than the rejection codes, which may be more 63 * useful for some other use-cases. 64 */ 65 enum class BlockValidationResult { 66 BLOCK_RESULT_UNSET = 0, //!< initial value. Block has not yet been rejected 67 BLOCK_CONSENSUS, //!< invalid by consensus rules (excluding any below reasons) 68 /** 69 * Invalid by a change to consensus rules more recent than SegWit. 70 * Currently unused as there are no such consensus rule changes, and any download 71 * sources realistically need to support SegWit in order to provide useful data, 72 * so differentiating between always-invalid and invalid-by-pre-SegWit-soft-fork 73 * is uninteresting. 74 */ 75 BLOCK_RECENT_CONSENSUS_CHANGE, 76 BLOCK_CACHED_INVALID, //!< this block was cached as being invalid and we didn't store the reason why 77 BLOCK_INVALID_HEADER, //!< invalid proof of work or time too old 78 BLOCK_MUTATED, //!< the block's data didn't match the data committed to by the PoW 79 BLOCK_MISSING_PREV, //!< We don't have the previous block the checked one is built on 80 BLOCK_INVALID_PREV, //!< A block this one builds on is invalid 81 BLOCK_TIME_FUTURE, //!< block timestamp was > 2 hours in the future (or our clock is bad) 82 BLOCK_CHECKPOINT, //!< the block failed to meet one of our checkpoints 83 BLOCK_HEADER_LOW_WORK //!< the block header may be on a too-little-work chain 84 }; 85 86 87 88 /** Template for capturing information about block/transaction validation. This is instantiated 89 * by TxValidationState and BlockValidationState for validation information on transactions 90 * and blocks respectively. */ 91 template <typename Result> 92 class ValidationState 93 { 94 private: 95 enum class ModeState { 96 M_VALID, //!< everything ok 97 M_INVALID, //!< network rule violation (DoS value may be set) 98 M_ERROR, //!< run-time error 99 } m_mode{ModeState::M_VALID}; 100 Result m_result{}; 101 std::string m_reject_reason; 102 std::string m_debug_message; 103 104 public: 105 bool Invalid(Result result, 106 const std::string& reject_reason = "", 107 const std::string& debug_message = "") 108 { 109 m_result = result; 110 m_reject_reason = reject_reason; 111 m_debug_message = debug_message; 112 if (m_mode != ModeState::M_ERROR) m_mode = ModeState::M_INVALID; 113 return false; 114 } 115 bool Error(const std::string& reject_reason) 116 { 117 if (m_mode == ModeState::M_VALID) 118 m_reject_reason = reject_reason; 119 m_mode = ModeState::M_ERROR; 120 return false; 121 } 122 bool IsValid() const { return m_mode == ModeState::M_VALID; } 123 bool IsInvalid() const { return m_mode == ModeState::M_INVALID; } 124 bool IsError() const { return m_mode == ModeState::M_ERROR; } 125 Result GetResult() const { return m_result; } 126 std::string GetRejectReason() const { return m_reject_reason; } 127 std::string GetDebugMessage() const { return m_debug_message; } 128 std::string ToString() const 129 { 130 if (IsValid()) { 131 return "Valid"; 132 } 133 134 if (!m_debug_message.empty()) { 135 return m_reject_reason + ", " + m_debug_message; 136 } 137 138 return m_reject_reason; 139 } 140 }; 141 142 class TxValidationState : public ValidationState<TxValidationResult> {}; 143 class BlockValidationState : public ValidationState<BlockValidationResult> {}; 144 145 // These implement the weight = (stripped_size * 4) + witness_size formula, 146 // using only serialization with and without witness data. As witness_size 147 // is equal to total_size - stripped_size, this formula is identical to: 148 // weight = (stripped_size * 3) + total_size. 149 static inline int32_t GetTransactionWeight(const CTransaction& tx) 150 { 151 return ::GetSerializeSize(TX_NO_WITNESS(tx)) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(TX_WITH_WITNESS(tx)); 152 } 153 static inline int64_t GetBlockWeight(const CBlock& block) 154 { 155 return ::GetSerializeSize(TX_NO_WITNESS(block)) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(TX_WITH_WITNESS(block)); 156 } 157 static inline int64_t GetTransactionInputWeight(const CTxIn& txin) 158 { 159 // scriptWitness size is added here because witnesses and txins are split up in segwit serialization. 160 return ::GetSerializeSize(TX_NO_WITNESS(txin)) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(TX_WITH_WITNESS(txin)) + ::GetSerializeSize(txin.scriptWitness.stack); 161 } 162 163 /** Compute at which vout of the block's coinbase transaction the witness commitment occurs, or -1 if not found */ 164 inline int GetWitnessCommitmentIndex(const CBlock& block) 165 { 166 int commitpos = NO_WITNESS_COMMITMENT; 167 if (!block.vtx.empty()) { 168 for (size_t o = 0; o < block.vtx[0]->vout.size(); o++) { 169 const CTxOut& vout = block.vtx[0]->vout[o]; 170 if (vout.scriptPubKey.size() >= MINIMUM_WITNESS_COMMITMENT && 171 vout.scriptPubKey[0] == OP_RETURN && 172 vout.scriptPubKey[1] == 0x24 && 173 vout.scriptPubKey[2] == 0xaa && 174 vout.scriptPubKey[3] == 0x21 && 175 vout.scriptPubKey[4] == 0xa9 && 176 vout.scriptPubKey[5] == 0xed) { 177 commitpos = o; 178 } 179 } 180 } 181 return commitpos; 182 } 183 184 #endif // BITCOIN_CONSENSUS_VALIDATION_H