1 files changed, 79 insertions, 27 deletions

diff --git a/src/consensus/validation.h b/src/consensus/validation.h
index f2e2c3585a..2e23f4b3a4 100644
--- a/src/consensus/validation.h
+++ b/src/consensus/validation.h
@@ -22,6 +22,78 @@ static const unsigned char REJECT_NONSTANDARD = 0x40;
 static const unsigned char REJECT_INSUFFICIENTFEE = 0x42;
 static const unsigned char REJECT_CHECKPOINT = 0x43;
 
+/** A "reason" why something was invalid, suitable for determining whether the
+  * provider of the object should be banned/ignored/disconnected/etc.
+  * These are much more granular than the rejection codes, which may be more
+  * useful for some other use-cases.
+  */
+enum class ValidationInvalidReason {
+    // txn and blocks:
+    NONE,                    //!< not actually invalid
+    CONSENSUS,               //!< invalid by consensus rules (excluding any below reasons)
+    /**
+     * Invalid by a change to consensus rules more recent than SegWit.
+     * Currently unused as there are no such consensus rule changes, and any download
+     * sources realistically need to support SegWit in order to provide useful data,
+     * so differentiating between always-invalid and invalid-by-pre-SegWit-soft-fork
+     * is uninteresting.
+     */
+    RECENT_CONSENSUS_CHANGE,
+    // Only blocks (or headers):
+    CACHED_INVALID,          //!< this object was cached as being invalid, but we don't know why
+    BLOCK_INVALID_HEADER,    //!< invalid proof of work or time too old
+    BLOCK_MUTATED,           //!< the block's data didn't match the data committed to by the PoW
+    BLOCK_MISSING_PREV,      //!< We don't have the previous block the checked one is built on
+    BLOCK_INVALID_PREV,      //!< A block this one builds on is invalid
+    BLOCK_TIME_FUTURE,          //!< block timestamp was > 2 hours in the future (or our clock is bad)
+    BLOCK_CHECKPOINT,        //!< the block failed to meet one of our checkpoints
+    // Only loose txn:
+    TX_NOT_STANDARD,          //!< didn't meet our local policy rules
+    TX_MISSING_INPUTS,        //!< a 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
+     * activation, or witness may have been malleated (which includes
+     * non-standard witnesses).
+     */
+    TX_WITNESS_MUTATED,
+    /**
+     * 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)
+     * TODO: Currently this is only used if the transaction already exists in the mempool or on chain,
+     * TODO: ATMP's fMissingInputs and a valid CValidationState being used to indicate missing inputs
+     */
+    TX_CONFLICT,
+    TX_MEMPOOL_POLICY,        //!< violated mempool's fee/size/descendant/RBF/etc limits
+};
+
+inline bool IsTransactionReason(ValidationInvalidReason r)
+{
+    return r == ValidationInvalidReason::NONE ||
+           r == ValidationInvalidReason::CONSENSUS ||
+           r == ValidationInvalidReason::RECENT_CONSENSUS_CHANGE ||
+           r == ValidationInvalidReason::TX_NOT_STANDARD ||
+           r == ValidationInvalidReason::TX_PREMATURE_SPEND ||
+           r == ValidationInvalidReason::TX_MISSING_INPUTS ||
+           r == ValidationInvalidReason::TX_WITNESS_MUTATED ||
+           r == ValidationInvalidReason::TX_CONFLICT ||
+           r == ValidationInvalidReason::TX_MEMPOOL_POLICY;
+}
+
+inline bool IsBlockReason(ValidationInvalidReason r)
+{
+    return r == ValidationInvalidReason::NONE ||
+           r == ValidationInvalidReason::CONSENSUS ||
+           r == ValidationInvalidReason::RECENT_CONSENSUS_CHANGE ||
+           r == ValidationInvalidReason::CACHED_INVALID ||
+           r == ValidationInvalidReason::BLOCK_INVALID_HEADER ||
+           r == ValidationInvalidReason::BLOCK_MUTATED ||
+           r == ValidationInvalidReason::BLOCK_MISSING_PREV ||
+           r == ValidationInvalidReason::BLOCK_INVALID_PREV ||
+           r == ValidationInvalidReason::BLOCK_TIME_FUTURE ||
+           r == ValidationInvalidReason::BLOCK_CHECKPOINT;
+}
+
 /** Capture information about block/transaction validation */
 class CValidationState {
 private:
@@ -30,32 +102,24 @@ private:
         MODE_INVALID, //!< network rule violation (DoS value may be set)
         MODE_ERROR,   //!< run-time error
     } mode;
-    int nDoS;
+    ValidationInvalidReason m_reason;
     std::string strRejectReason;
     unsigned int chRejectCode;
-    bool corruptionPossible;
     std::string strDebugMessage;
 public:
-    CValidationState() : mode(MODE_VALID), nDoS(0), chRejectCode(0), corruptionPossible(false) {}
-    bool DoS(int level, bool ret = false,
-             unsigned int chRejectCodeIn=0, const std::string &strRejectReasonIn="",
-             bool corruptionIn=false,
-             const std::string &strDebugMessageIn="") {
+    CValidationState() : mode(MODE_VALID), m_reason(ValidationInvalidReason::NONE), chRejectCode(0) {}
+    bool Invalid(ValidationInvalidReason reasonIn, bool ret = false,
+            unsigned int chRejectCodeIn=0, const std::string &strRejectReasonIn="",
+            const std::string &strDebugMessageIn="") {
+        m_reason = reasonIn;
         chRejectCode = chRejectCodeIn;
         strRejectReason = strRejectReasonIn;
-        corruptionPossible = corruptionIn;
         strDebugMessage = strDebugMessageIn;
         if (mode == MODE_ERROR)
             return ret;
-        nDoS += level;
         mode = MODE_INVALID;
         return ret;
     }
-    bool Invalid(bool ret = false,
-                 unsigned int _chRejectCode=0, const std::string &_strRejectReason="",
-                 const std::string &_strDebugMessage="") {
-        return DoS(0, ret, _chRejectCode, _strRejectReason, false, _strDebugMessage);
-    }
     bool Error(const std::string& strRejectReasonIn) {
         if (mode == MODE_VALID)
             strRejectReason = strRejectReasonIn;
@@ -71,19 +135,7 @@ public:
     bool IsError() const {
         return mode == MODE_ERROR;
     }
-    bool IsInvalid(int &nDoSOut) const {
-        if (IsInvalid()) {
-            nDoSOut = nDoS;
-            return true;
-        }
-        return false;
-    }
-    bool CorruptionPossible() const {
-        return corruptionPossible;
-    }
-    void SetCorruptionPossible() {
-        corruptionPossible = true;
-    }
+    ValidationInvalidReason GetReason() const { return m_reason; }
     unsigned int GetRejectCode() const { return chRejectCode; }
     std::string GetRejectReason() const { return strRejectReason; }
     std::string GetDebugMessage() const { return strDebugMessage; }