1 files changed, 52 insertions, 17 deletions

diff --git a/src/consensus/validation.h b/src/consensus/validation.h
index a79e7b9d12..6027bb9aeb 100644
--- a/src/consensus/validation.h
+++ b/src/consensus/validation.h
@@ -1,5 +1,5 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2019 The Bitcoin Core developers
+// Copyright (c) 2009-2021 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -12,6 +12,12 @@
 #include <primitives/transaction.h>
 #include <primitives/block.h>
 
+/** Index marker for when no witness commitment is present in a coinbase transaction. */
+static constexpr int NO_WITNESS_COMMITMENT{-1};
+
+/** Minimum size of a witness commitment structure. Defined in BIP 141. **/
+static constexpr size_t MINIMUM_WITNESS_COMMITMENT{38};
+
 /** A "reason" why a transaction was invalid, suitable for determining whether the
   * provider of the transaction should be banned/ignored/disconnected/etc.
   */
@@ -26,22 +32,28 @@ enum class TxValidationResult {
      * is uninteresting.
      */
     TX_RECENT_CONSENSUS_CHANGE,
-    TX_NOT_STANDARD,          //!< didn't meet our local policy rules
+    TX_INPUTS_NOT_STANDARD,   //!< inputs (covered by txid) failed policy rules
+    TX_NOT_STANDARD,          //!< otherwise didn't meet our local policy rules
     TX_MISSING_INPUTS,        //!< transaction was missing some of its inputs
     TX_PREMATURE_SPEND,       //!< transaction spends a coinbase too early, or violates locktime/sequence locks
     /**
-     * Transaction might be missing a witness, have a witness prior to SegWit
+     * Transaction might have a witness prior to SegWit
      * activation, or witness may have been malleated (which includes
      * non-standard witnesses).
      */
     TX_WITNESS_MUTATED,
     /**
+     * Transaction is missing a witness.
+     */
+    TX_WITNESS_STRIPPED,
+    /**
      * Tx already in mempool or conflicts with a tx in the chain
      * (if it conflicts with another tx in mempool, we use MEMPOOL_POLICY as it failed to reach the RBF threshold)
      * Currently this is only used if the transaction already exists in the mempool or on chain.
      */
     TX_CONFLICT,
     TX_MEMPOOL_POLICY,        //!< violated mempool's fee/size/descendant/RBF/etc limits
+    TX_NO_MEMPOOL,            //!< this node does not have a mempool so can't validate the transaction
 };
 
 /** A "reason" why a block was invalid, suitable for determining whether the
@@ -75,37 +87,39 @@ enum class BlockValidationResult {
  *  by TxValidationState and BlockValidationState for validation information on transactions
  *  and blocks respectively. */
 template <typename Result>
-class ValidationState {
+class ValidationState
+{
 private:
-    enum mode_state {
-        MODE_VALID,   //!< everything ok
-        MODE_INVALID, //!< network rule violation (DoS value may be set)
-        MODE_ERROR,   //!< run-time error
-    } m_mode{MODE_VALID};
+    enum class ModeState {
+        M_VALID,   //!< everything ok
+        M_INVALID, //!< network rule violation (DoS value may be set)
+        M_ERROR,   //!< run-time error
+    } m_mode{ModeState::M_VALID};
     Result m_result{};
     std::string m_reject_reason;
     std::string m_debug_message;
+
 public:
     bool Invalid(Result result,
-                 const std::string &reject_reason="",
-                 const std::string &debug_message="")
+                 const std::string& reject_reason = "",
+                 const std::string& debug_message = "")
     {
         m_result = result;
         m_reject_reason = reject_reason;
         m_debug_message = debug_message;
-        if (m_mode != MODE_ERROR) m_mode = MODE_INVALID;
+        if (m_mode != ModeState::M_ERROR) m_mode = ModeState::M_INVALID;
         return false;
     }
     bool Error(const std::string& reject_reason)
     {
-        if (m_mode == MODE_VALID)
+        if (m_mode == ModeState::M_VALID)
             m_reject_reason = reject_reason;
-        m_mode = MODE_ERROR;
+        m_mode = ModeState::M_ERROR;
         return false;
     }
-    bool IsValid() const { return m_mode == MODE_VALID; }
-    bool IsInvalid() const { return m_mode == MODE_INVALID; }
-    bool IsError() const { return m_mode == MODE_ERROR; }
+    bool IsValid() const { return m_mode == ModeState::M_VALID; }
+    bool IsInvalid() const { return m_mode == ModeState::M_INVALID; }
+    bool IsError() const { return m_mode == ModeState::M_ERROR; }
     Result GetResult() const { return m_result; }
     std::string GetRejectReason() const { return m_reject_reason; }
     std::string GetDebugMessage() const { return m_debug_message; }
@@ -144,4 +158,25 @@ static inline int64_t GetTransactionInputWeight(const CTxIn& txin)
     return ::GetSerializeSize(txin, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(txin, PROTOCOL_VERSION) + ::GetSerializeSize(txin.scriptWitness.stack, PROTOCOL_VERSION);
 }
 
+/** Compute at which vout of the block's coinbase transaction the witness commitment occurs, or -1 if not found */
+inline int GetWitnessCommitmentIndex(const CBlock& block)
+{
+    int commitpos = NO_WITNESS_COMMITMENT;
+    if (!block.vtx.empty()) {
+        for (size_t o = 0; o < block.vtx[0]->vout.size(); o++) {
+            const CTxOut& vout = block.vtx[0]->vout[o];
+            if (vout.scriptPubKey.size() >= MINIMUM_WITNESS_COMMITMENT &&
+                vout.scriptPubKey[0] == OP_RETURN &&
+                vout.scriptPubKey[1] == 0x24 &&
+                vout.scriptPubKey[2] == 0xaa &&
+                vout.scriptPubKey[3] == 0x21 &&
+                vout.scriptPubKey[4] == 0xa9 &&
+                vout.scriptPubKey[5] == 0xed) {
+                commitpos = o;
+            }
+        }
+    }
+    return commitpos;
+}
+
 #endif // BITCOIN_CONSENSUS_VALIDATION_H