v29.4-roots.2 · Commit 3: [PATCH 03/21] policy: restore conservative relay and network controls

src/validation.cpp

Before: src/validation.cpp · After: src/validation.cpp

File metadata

index ff281bc1a6f885fd9efe1f01cfc2b91d230df084..c2530e7d119fcc4fe7fb0f89824eeaad60e13a37 100644

Download original patch · Release notes

Diff rows 1–400 of 802. Line numbers refer to the original before/after files.

+ Added− RemovedUnmarked lines are context.

Scroll the code area horizontally to read long lines. The two line-number columns refer to before and after.

src/validation.cpp CHANGED Viewed

@@ -104,6 +104,8 @@ const std::vector<std::string> CHECKLEVEL_DOC {
     "level 4 tries to reconnect the blocks",
     "each level includes the checks of the previous levels",
 };
+SpkReuseModes SpkReuseMode{SRM_ALLOW};
 /** The number of blocks to keep below the deepest prune lock.
  *  There is nothing special about this number. It is higher than what we
  *  expect to see in regular mainnet reorgs, but not so high that it would
@@ -270,7 +272,39 @@ bool CheckSequenceLocksAtTip(CBlockIndex* tip,
 // Returns the script flags which should be checked for a given block
 static unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman);
-static void LimitMempoolSize(CTxMemPool& pool, CCoinsViewCache& coins_cache)
+/** Compute accurate total signature operation cost of a transaction.
+ *  Not consensus-critical, since legacy sigops counting is always used in the protocol.
+ */
+int64_t GetAccurateTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, int flags)
+{
+    if (tx.IsCoinBase()) {
+        return 0;
+    }
+    unsigned int nSigOps = 0;
+    for (const auto& txin : tx.vin) {
+        nSigOps += txin.scriptSig.GetSigOpCount(false);
+    }
+    if (flags & SCRIPT_VERIFY_P2SH) {
+        nSigOps += GetP2SHSigOpCount(tx, inputs);
+    }
+    nSigOps *= WITNESS_SCALE_FACTOR;
+    if (flags & SCRIPT_VERIFY_WITNESS) {
+        for (const auto& txin : tx.vin) {
+            const Coin& coin = inputs.AccessCoin(txin.prevout);
+            assert(!coin.IsSpent());
+            const CTxOut &prevout = coin.out;
+            nSigOps += CountWitnessSigOps(txin.scriptSig, prevout.scriptPubKey, &txin.scriptWitness, flags);
+        }
+    }
+    return nSigOps;
+}
+void LimitMempoolSize(CTxMemPool& pool, CCoinsViewCache& coins_cache)
     EXCLUSIVE_LOCKS_REQUIRED(::cs_main, pool.cs)
 {
     AssertLockHeld(::cs_main);
@@ -457,7 +491,7 @@ public:
     struct ATMPArgs {
         const CChainParams& m_chainparams;
         const int64_t m_accept_time;
-        const bool m_bypass_limits;
+        const ignore_rejects_type& m_ignore_rejects;
         /*
          * Return any outpoints which were not previously present in the coins
          * cache, but were added as a result of validating the tx for mempool
@@ -494,11 +528,11 @@ public:
         /** Parameters for single transaction mempool validation. */
         static ATMPArgs SingleAccept(const CChainParams& chainparams, int64_t accept_time,
-                                     bool bypass_limits, std::vector<COutPoint>& coins_to_uncache,
+                                     const ignore_rejects_type& ignore_rejects, std::vector<COutPoint>& coins_to_uncache,
                                      bool test_accept) {
             return ATMPArgs{/* m_chainparams */ chainparams,
                             /* m_accept_time */ accept_time,
-                            /* m_bypass_limits */ bypass_limits,
+                            /* m_ignore_rejects */ ignore_rejects,
                             /* m_coins_to_uncache */ coins_to_uncache,
                             /* m_test_accept */ test_accept,
                             /* m_allow_replacement */ true,
@@ -512,10 +546,10 @@ public:
         /** Parameters for test package mempool validation through testmempoolaccept. */
         static ATMPArgs PackageTestAccept(const CChainParams& chainparams, int64_t accept_time,
-                                          std::vector<COutPoint>& coins_to_uncache) {
+                                          const ignore_rejects_type& ignore_rejects, std::vector<COutPoint>& coins_to_uncache) {
             return ATMPArgs{/* m_chainparams */ chainparams,
                             /* m_accept_time */ accept_time,
-                            /* m_bypass_limits */ false,
+                            /* m_ignore_rejects */ ignore_rejects,
                             /* m_coins_to_uncache */ coins_to_uncache,
                             /* m_test_accept */ true,
                             /* m_allow_replacement */ false,
@@ -529,10 +563,10 @@ public:
         /** Parameters for child-with-unconfirmed-parents package validation. */
         static ATMPArgs PackageChildWithParents(const CChainParams& chainparams, int64_t accept_time,
-                                                std::vector<COutPoint>& coins_to_uncache, const std::optional<CFeeRate>& client_maxfeerate) {
+                                                std::vector<COutPoint>& coins_to_uncache, const std::optional<CFeeRate>& client_maxfeerate, const ignore_rejects_type& ignore_rejects) {
             return ATMPArgs{/* m_chainparams */ chainparams,
                             /* m_accept_time */ accept_time,
-                            /* m_bypass_limits */ false,
+                            /* m_ignore_rejects */ ignore_rejects,
                             /* m_coins_to_uncache */ coins_to_uncache,
                             /* m_test_accept */ false,
                             /* m_allow_replacement */ true,
@@ -548,7 +582,7 @@ public:
         static ATMPArgs SingleInPackageAccept(const ATMPArgs& package_args) {
             return ATMPArgs{/* m_chainparams */ package_args.m_chainparams,
                             /* m_accept_time */ package_args.m_accept_time,
-                            /* m_bypass_limits */ false,
+                            empty_ignore_rejects,
                             /* m_coins_to_uncache */ package_args.m_coins_to_uncache,
                             /* m_test_accept */ package_args.m_test_accept,
                             /* m_allow_replacement */ true,
@@ -565,7 +599,7 @@ public:
         // mixing up the order of the arguments. Use static functions above instead.
         ATMPArgs(const CChainParams& chainparams,
                  int64_t accept_time,
-                 bool bypass_limits,
+                 const ignore_rejects_type& ignore_rejects,
                  std::vector<COutPoint>& coins_to_uncache,
                  bool test_accept,
                  bool allow_replacement,
@@ -576,7 +610,7 @@ public:
                  bool allow_carveouts)
             : m_chainparams{chainparams},
               m_accept_time{accept_time},
-              m_bypass_limits{bypass_limits},
+              m_ignore_rejects{ignore_rejects},
               m_coins_to_uncache{coins_to_uncache},
               m_test_accept{test_accept},
               m_allow_replacement{allow_replacement},
@@ -636,7 +670,8 @@ private:
         explicit Workspace(const CTransactionRef& ptx) : m_ptx(ptx), m_hash(ptx->GetHash()) {}
         /** Txids of mempool transactions that this transaction directly conflicts with or may
          * replace via sibling eviction. */
-        std::set<Txid> m_conflicts;
+        /** .second=true is a consensus conflict, and .second=false is a policy conflict. */
+        std::map<Txid, bool> m_conflicts_incl_policy;
         /** Iterators to mempool entries that this transaction directly conflicts with or may
          * replace via sibling eviction. */
         CTxMemPool::setEntries m_iters_conflicting;
@@ -670,6 +705,23 @@ private:
         PrecomputedTransactionData m_precomputed_txdata;
     };
+    static inline bool MaybeReject_(TxValidationResult reason, const std::string& reason_str, const std::string& debug_msg, const ignore_rejects_type& ignore_rejects, TxValidationState& state) {
+        if (ignore_rejects.count(reason_str)) {
+            return false;
+        }
+        state.Invalid(reason, reason_str, debug_msg);
+        return true;
+    }
+#define MaybeRejectDbg(reason, reason_str, debug_msg)  do {  \
+    if (MaybeReject_(reason, reason_str, debug_msg, ignore_rejects, state)) {  \
+        return false;  \
+    }  \
+} while(0)
+#define MaybeReject(reason, reason_str)  MaybeRejectDbg(reason, reason_str, "")
     // Run the policy checks on a given transaction, excluding any script checks.
     // Looks up inputs, calculates feerate, considers replacement, evaluates
     // package limits, etc. As this function can be invoked for "free" by a peer,
@@ -677,11 +729,11 @@ private:
     bool PreChecks(ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
     // Run checks for mempool replace-by-fee, only used in AcceptSingleTransaction.
-    bool ReplacementChecks(Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
+    bool ReplacementChecks(ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
     // Enforce package mempool ancestor/descendant limits (distinct from individual
     // ancestor/descendant limits done in PreChecks) and run Package RBF checks.
-    bool PackageMempoolChecks(const std::vector<CTransactionRef>& txns,
+    bool PackageMempoolChecks(const ATMPArgs& args, const std::vector<CTransactionRef>& txns,
                               std::vector<Workspace>& workspaces,
                               int64_t total_vsize,
                               PackageValidationState& package_state) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
@@ -707,16 +759,16 @@ private:
          EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
     // Compare a package's feerate against minimum allowed.
-    bool CheckFeeRate(size_t package_size, CAmount package_fee, TxValidationState& state) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, m_pool.cs)
+    bool CheckFeeRate(size_t package_size, CAmount package_fee, TxValidationState& state, const ignore_rejects_type& ignore_rejects) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, m_pool.cs)
     {
         AssertLockHeld(::cs_main);
         AssertLockHeld(m_pool.cs);
         CAmount mempoolRejectFee = m_pool.GetMinFee().GetFee(package_size);
-        if (mempoolRejectFee > 0 && package_fee < mempoolRejectFee) {
+        if (mempoolRejectFee > 0 && package_fee < mempoolRejectFee && !ignore_rejects.count(rejectmsg_lowfee_mempool)) {
             return state.Invalid(TxValidationResult::TX_RECONSIDERABLE, "mempool min fee not met", strprintf("%d < %d", package_fee, mempoolRejectFee));
         }
-        if (package_fee < m_pool.m_opts.min_relay_feerate.GetFee(package_size)) {
+        if (package_fee < m_pool.m_opts.min_relay_feerate.GetFee(package_size) && !ignore_rejects.count(rejectmsg_lowfee_relay)) {
             return state.Invalid(TxValidationResult::TX_RECONSIDERABLE, "min relay fee not met",
                                  strprintf("%d < %d", package_fee, m_pool.m_opts.min_relay_feerate.GetFee(package_size)));
         }
@@ -781,7 +833,7 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
     // Copy/alias what we need out of args
     const int64_t nAcceptTime = args.m_accept_time;
-    const bool bypass_limits = args.m_bypass_limits;
+    const ignore_rejects_type& ignore_rejects = args.m_ignore_rejects;
     std::vector<COutPoint>& coins_to_uncache = args.m_coins_to_uncache;
     // Alias what we need out of ws
@@ -795,21 +847,25 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
     if (tx.IsCoinBase())
         return state.Invalid(TxValidationResult::TX_CONSENSUS, "coinbase");
+    if (tx.version == TRUC_VERSION && m_pool.m_opts.truc_policy == TRUCPolicy::Reject) {
+        return state.Invalid(TxValidationResult::TX_NOT_STANDARD, "version");
+    }
     // Rather not work on nonstandard transactions (unless -testnet/-regtest)
     std::string reason;
-    if (m_pool.m_opts.require_standard && !IsStandardTx(tx, m_pool.m_opts.max_datacarrier_bytes, m_pool.m_opts.permit_bare_multisig, m_pool.m_opts.dust_relay_feerate, reason)) {
+    if (m_pool.m_opts.require_standard && !IsStandardTx(tx, m_pool.m_opts, reason, ignore_rejects)) {
         return state.Invalid(TxValidationResult::TX_NOT_STANDARD, reason);
     }
     // Transactions smaller than 65 non-witness bytes are not relayed to mitigate CVE-2017-12842.
     if (::GetSerializeSize(TX_NO_WITNESS(tx)) < MIN_STANDARD_TX_NONWITNESS_SIZE)
-        return state.Invalid(TxValidationResult::TX_NOT_STANDARD, "tx-size-small");
+        MaybeReject(TxValidationResult::TX_NOT_STANDARD, "tx-size-small");
     // Only accept nLockTime-using transactions that can be mined in the next
     // block; we don't want our mempool filled up with transactions that can't
     // be mined yet.
     if (!CheckFinalTxAtTip(*Assert(m_active_chainstate.m_chain.Tip()), tx)) {
-        return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND, "non-final");
+        MaybeReject(TxValidationResult::TX_PREMATURE_SPEND, "non-final");
     }
     if (m_pool.exists(GenTxid::Wtxid(tx.GetWitnessHash()))) {
@@ -821,16 +877,68 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
         return state.Invalid(TxValidationResult::TX_CONFLICT, "txn-same-nonwitness-data-in-mempool");
     }
+    auto spk_reuse_mode = SpkReuseMode;
+    if (ignore_rejects.count("txn-spk-reused")) {
+        spk_reuse_mode = SRM_ALLOW;
+    }
+    SPKStates_t mapSPK;
     // Check for conflicts with in-memory transactions
     for (const CTxIn &txin : tx.vin)
     {
         const CTransaction* ptxConflicting = m_pool.GetConflictTx(txin.prevout);
         if (ptxConflicting) {
             if (!args.m_allow_replacement) {
-                // Transaction conflicts with a mempool tx, but we're not allowing replacements in this context.
+                // Transaction conflicts with a mempool tx, but we're not allowing replacements.
                 return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "bip125-replacement-disallowed");
             }
-            ws.m_conflicts.insert(ptxConflicting->GetHash());
+            if (!ws.m_conflicts_incl_policy.count(ptxConflicting->GetHash()))
+            {
+                // Transactions that don't explicitly signal replaceability are
+                // *not* replaceable with the current logic, even if one of their
+                // unconfirmed ancestors signals replaceability. This diverges
+                // from BIP125's inherited signaling description (see CVE-2021-31876).
+                // Applications relying on first-seen mempool behavior should
+                // check all unconfirmed ancestors; otherwise an opt-in ancestor
+                // might be replaced, causing removal of this descendant.
+                //
+                // All TRUC transactions are considered replaceable.
+                //
+                // Replaceability signaling of the original transactions may be
+                // ignored due to node setting.
+                bool allow_rbf;
+                if (m_pool.m_opts.rbf_policy == RBFPolicy::Always || ignore_rejects.count("txn-mempool-conflict")) {
+                    allow_rbf = true;
+                } else if (m_pool.m_opts.rbf_policy == RBFPolicy::Never) {
+                    allow_rbf = false;
+                } else {
+                    allow_rbf = SignalsOptInRBF(*ptxConflicting) || ptxConflicting->version == TRUC_VERSION;
+                }
+                if (!allow_rbf) {
+                    return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "txn-mempool-conflict");
+                }
+                ws.m_conflicts_incl_policy.emplace(ptxConflicting->GetHash(), true);
+            }
+        }
+    }
+    if (spk_reuse_mode != SRM_ALLOW) {
+        for (const CTxOut& txout : tx.vout) {
+            uint160 hashSPK = ScriptHashkey(txout.scriptPubKey);
+            const auto& SPKUsedIn = m_pool.mapUsedSPK.find(hashSPK);
+            if (SPKUsedIn != m_pool.mapUsedSPK.end()) {
+                if (SPKUsedIn->second.first) {
+                    ws.m_conflicts_incl_policy.emplace(SPKUsedIn->second.first->GetHash(), false);
+                }
+                if (SPKUsedIn->second.second) {
+                    ws.m_conflicts_incl_policy.emplace(SPKUsedIn->second.second->GetHash(), false);
+                }
+            }
+            if (mapSPK.find(hashSPK) != mapSPK.end()) {
+                MaybeReject(TxValidationResult::TX_MEMPOOL_POLICY, "txn-spk-reused-twinoutputs");
+            }
+            mapSPK[hashSPK] = MemPool_SPK_State(mapSPK[hashSPK] | MSS_CREATED);
         }
     }
@@ -876,22 +984,67 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
     // Pass in m_view which has all of the relevant inputs cached. Note that, since m_view's
     // backend was removed, it no longer pulls coins from the mempool.
     const std::optional<LockPoints> lock_points{CalculateLockPointsAtTip(m_active_chainstate.m_chain.Tip(), m_view, tx)};
+    // NOTE: The miner doesn't check this again, so for now it may not be overridden.
     if (!lock_points.has_value() || !CheckSequenceLocksAtTip(m_active_chainstate.m_chain.Tip(), *lock_points)) {
         return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND, "non-BIP68-final");
     }
     // The mempool holds txs for the next block, so pass height+1 to CheckTxInputs
-    if (!Consensus::CheckTxInputs(tx, state, m_view, m_active_chainstate.m_chain.Height() + 1, ws.m_base_fees)) {
+    const auto block_height_current = m_active_chainstate.m_chain.Height();
+    const auto block_height_next = block_height_current + 1;
+    if (!Consensus::CheckTxInputs(tx, state, m_view, block_height_next, ws.m_base_fees)) {
         return false; // state filled in by CheckTxInputs
     }
-    if (m_pool.m_opts.require_standard && !AreInputsStandard(tx, m_view)) {
-        return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD, "bad-txns-nonstandard-inputs");
+    if (m_pool.m_opts.minrelaymaturity) {
+        auto max_coin_height = block_height_next - m_pool.m_opts.minrelaymaturity;
+        static_assert(std::is_signed_v<decltype(max_coin_height)>, "Unsigned max_coin_height needs a range check");
+        for (const CTxIn &txin : tx.vin) {
+            const Coin &coin = m_view.AccessCoin(txin.prevout);
+            if (coin.nHeight > max_coin_height) {
+                MaybeReject(TxValidationResult::TX_PREMATURE_SPEND, "bad-txns-input-immature-depth");
+            }
+        }
+    }
+    if (spk_reuse_mode != SRM_ALLOW) {
+        for (const CTxIn& txin : tx.vin) {
+            const Coin &coin = m_view.AccessCoin(txin.prevout);
+            uint160 hashSPK = ScriptHashkey(coin.out.scriptPubKey);
+            SPKStates_t::iterator mssit = mapSPK.find(hashSPK);
+            if (mssit != mapSPK.end()) {
+                if (mssit->second & MSS_CREATED) {
+                    MaybeReject(TxValidationResult::TX_MEMPOOL_POLICY, "txn-spk-reused-change");
+                }
+            }
+            const auto& SPKit = m_pool.mapUsedSPK.find(hashSPK);
+            if (SPKit != m_pool.mapUsedSPK.end()) {
+                if (SPKit->second.second /* Spent */) {
+                    ws.m_conflicts_incl_policy.emplace(SPKit->second.second->GetHash(), false);
+                }
+            }
+            mapSPK[hashSPK] = MemPool_SPK_State(mapSPK[hashSPK] | MSS_SPENT);
+        }
+    }
+    if (m_pool.m_opts.require_standard && !AreInputsStandard(tx, m_view, m_pool.m_opts, "bad-txns-input-", reason, ignore_rejects)) {
+        return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD, reason);
+    }
+    if (m_pool.m_opts.datacarrier_fullcount || !m_pool.m_opts.accept_non_std_datacarrier) {
+        const auto dcb = DatacarrierBytes(tx, m_view);
+        if (dcb.second > 0 && !(m_pool.m_opts.accept_non_std_datacarrier || ignore_rejects.count("txn-datacarrier-nonstandard"))) {
+            return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD, "txn-datacarrier-nonstandard");
+        }
+        if (m_pool.m_opts.datacarrier_fullcount && (!ignore_rejects.count("txn-datacarrier-exceeded")) && dcb.first + dcb.second > m_pool.m_opts.max_datacarrier_bytes.value_or(0)) {
+            return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD, "txn-datacarrier-exceeded");
+        }
     }
     // Check for non-standard witnesses.
-    if (tx.HasWitness() && m_pool.m_opts.require_standard && !IsWitnessStandard(tx, m_view)) {
-        return state.Invalid(TxValidationResult::TX_WITNESS_MUTATED, "bad-witness-nonstandard");
+    if (tx.HasWitness() && m_pool.m_opts.require_standard && !IsWitnessStandard(tx, m_view, "bad-witness-", reason, ignore_rejects)) {
+        return state.Invalid(TxValidationResult::TX_WITNESS_MUTATED, reason);
     }
     int64_t nSigOpsCost = GetTransactionSigOpCost(tx, m_view, STANDARD_SCRIPT_VERIFY_FLAGS);
@@ -907,29 +1060,63 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
         }
     }
-    // Set entry_sequence to 0 when bypass_limits is used; this allows txs from a block
+    // Since entries arrive *after* the tip's height, their priority is for the height+1
+    const auto coin_age = GetCoinAge(tx, m_view, block_height_next);
+    if (coin_age.inputs_coin_age < m_pool.m_opts.minrelaycoinblocks) {
+        MaybeReject(TxValidationResult::TX_PREMATURE_SPEND, "bad-txns-input-immature-coinblocks");
+    }
+    // Set entry_sequence to 0 when rejectmsg_zero_mempool_entry_seq is used; this allows txs from a block
     // reorg to be marked earlier than any child txs that were already in the mempool.
-    const uint64_t entry_sequence = bypass_limits ? 0 : m_pool.GetSequence();
+    const uint64_t entry_sequence = args.m_ignore_rejects.count(rejectmsg_zero_mempool_entry_seq) ? 0 : m_pool.GetSequence();
+    int32_t extra_weight = CalculateExtraTxWeight(*ptx, m_view, ::g_weight_per_data_byte);
     if (!m_subpackage.m_changeset) {
         m_subpackage.m_changeset = m_pool.GetChangeSet();
     }
-    ws.m_tx_handle = m_subpackage.m_changeset->StageAddition(ptx, ws.m_base_fees, nAcceptTime, m_active_chainstate.m_chain.Height(), entry_sequence, fSpendsCoinbase, nSigOpsCost, lock_points.value());
+    ws.m_tx_handle = m_subpackage.m_changeset->StageAddition(ptx, ws.m_base_fees, nAcceptTime, block_height_current, entry_sequence, coin_age, fSpendsCoinbase, /*extra_weight=*/ extra_weight, /*sigops_cost=*/ nSigOpsCost, lock_points.value());
+    if (spk_reuse_mode != SRM_ALLOW) {
+        m_subpackage.m_changeset->m_to_add.modify(ws.m_tx_handle, [=](CTxMemPoolEntry& e) {
+            e.mapSPK = mapSPK;
+        });
+    }
     // ws.m_modified_fees includes any fee deltas from PrioritiseTransaction
     ws.m_modified_fees = ws.m_tx_handle->GetModifiedFee();
     ws.m_vsize = ws.m_tx_handle->GetTxSize();
+    // Reduce effective fee by dust threshold for each sub-dust output
+    if (m_pool.m_opts.subdustfeepenalty) {
+        CAmount dust_penalty{0};
+        for (const auto& txout : tx.vout) {
+            const CAmount dust_threshold = GetDustThreshold(txout, m_pool.m_opts.dust_relay_feerate);
+            if (txout.nValue < dust_threshold) {
+                dust_penalty = SaturatingAdd(dust_penalty, dust_threshold - txout.nValue);
+            }