feat: Integrate Permissioned Domain & Credential Checks for Lending Protocol

include/xrpl/protocol/LedgerFormats.h

@@ -203,7 +203,10 @@ enum LedgerEntryType : std::uint16_t {
     LEDGER_OBJECT(Loan,                                                                                                            \
         LSF_FLAG(lsfLoanDefault, 0x00010000)                                                                                       \
         LSF_FLAG(lsfLoanImpaired, 0x00020000)                                                                                      \
-        LSF_FLAG(lsfLoanOverpayment, 0x00040000))               /* True, loan allows overpayments */
+        LSF_FLAG(lsfLoanOverpayment, 0x00040000))               /* True, loan allows overpayments */                               \
+                                                                                                                                   \
+    LEDGER_OBJECT(LoanBroker,                                                                                                      \
+        LSF_FLAG(lsfLoanBrokerPrivate, 0x00010000))
 
 // clang-format on
 

include/xrpl/protocol/TxFlags.h

@@ -214,6 +214,10 @@ inline constexpr FlagValue tfUniversalMask = ~tfUniversal;
         TF_FLAG(tfLoanDefault, 0x00010000)                                                                                                                     \
         TF_FLAG(tfLoanImpair, 0x00020000)                                                                                                                      \
         TF_FLAG(tfLoanUnimpair, 0x00040000),                                                                                                                   \
+        MASK_ADJ(0))                                                                                                                                           \
+                                                                                                                                                               \
+    TRANSACTION(LoanBrokerSet,                                                                                                                                    \
+        TF_FLAG(tfLoanBrokerPrivate, 0x00010000),                                                                                                             \
         MASK_ADJ(0))
 
 // clang-format on

include/xrpl/protocol/detail/features.macro

@@ -15,6 +15,7 @@
 // Add new amendments to the top of this list.
 // Keep it sorted in reverse chronological order.
 
+XRPL_FEATURE(LendingPermissionedDomain,   Supported::No,  VoteBehavior::DefaultNo)
 XRPL_FIX    (Cleanup3_2_0,                Supported::Yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(MPTokensV2,                  Supported::No,  VoteBehavior::DefaultNo)
 XRPL_FIX    (Cleanup3_1_3,                Supported::Yes, VoteBehavior::DefaultYes)

include/xrpl/protocol/detail/ledger_entries.macro

@@ -519,6 +519,7 @@ LEDGER_ENTRY(ltLOAN_BROKER, 0x0088, LoanBroker, loan_broker, ({
     {sfCoverAvailable,       SoeDefault},
     {sfCoverRateMinimum,     SoeDefault},
     {sfCoverRateLiquidation, SoeDefault},
+    {sfDomainID,             SoeOptional},
 }))
 
 /** A ledger object representing a loan between a Borrower and a Loan Broker

include/xrpl/protocol/detail/transactions.macro

@@ -961,6 +961,7 @@ TRANSACTION(ttLOAN_BROKER_SET, 74, LoanBrokerSet,
     {sfDebtMaximum, SoeOptional},
     {sfCoverRateMinimum, SoeOptional},
     {sfCoverRateLiquidation, SoeOptional},
+    {sfDomainID,             SoeOptional},
 }))
 
 /** This transaction deletes a Loan Broker */

include/xrpl/protocol_autogen/ledger_entries/LoanBroker.h

@@ -335,6 +335,30 @@ class LoanBroker : public LedgerEntryBase
     {
         return this->sle_->isFieldPresent(sfCoverRateLiquidation);
     }
+
+    /**
+     * @brief Get sfDomainID (SoeOptional)
+     * @return The field value, or std::nullopt if not present.
+     */
+    [[nodiscard]]
+    protocol_autogen::Optional<SF_UINT256::type::value_type>
+    getDomainID() const
+    {
+        if (hasDomainID())
+            return this->sle_->at(sfDomainID);
+        return std::nullopt;
+    }
+
+    /**
+     * @brief Check if sfDomainID is present.
+     * @return True if the field is present, false otherwise.
+     */
+    [[nodiscard]]
+    bool
+    hasDomainID() const
+    {
+        return this->sle_->isFieldPresent(sfDomainID);
+    }
 };
 
 /**
@@ -576,6 +600,17 @@ class LoanBrokerBuilder : public LedgerEntryBuilderBase<LoanBrokerBuilder>
         return *this;
     }
 
+    /**
+     * @brief Set sfDomainID (SoeOptional)
+     * @return Reference to this builder for method chaining.
+     */
+    LoanBrokerBuilder&
+    setDomainID(std::decay_t<typename SF_UINT256::type::value_type> const& value)
+    {
+        object_[sfDomainID] = value;
+        return *this;
+    }
+
     /**
      * @brief Build and return the completed LoanBroker wrapper.
      * @param index The ledger entry index.

include/xrpl/protocol_autogen/transactions/LoanBrokerSet.h

@@ -213,6 +213,32 @@ class LoanBrokerSet : public TransactionBase
     {
         return this->tx_->isFieldPresent(sfCoverRateLiquidation);
     }
+
+    /**
+     * @brief Get sfDomainID (SoeOptional)
+     * @return The field value, or std::nullopt if not present.
+     */
+    [[nodiscard]]
+    protocol_autogen::Optional<SF_UINT256::type::value_type>
+    getDomainID() const
+    {
+        if (hasDomainID())
+        {
+            return this->tx_->at(sfDomainID);
+        }
+        return std::nullopt;
+    }
+
+    /**
+     * @brief Check if sfDomainID is present.
+     * @return True if the field is present, false otherwise.
+     */
+    [[nodiscard]]
+    bool
+    hasDomainID() const
+    {
+        return this->tx_->isFieldPresent(sfDomainID);
+    }
 };
 
 /**
@@ -334,6 +360,17 @@ class LoanBrokerSetBuilder : public TransactionBuilderBase<LoanBrokerSetBuilder>
         return *this;
     }
 
+    /**
+     * @brief Set sfDomainID (SoeOptional)
+     * @return Reference to this builder for method chaining.
+     */
+    LoanBrokerSetBuilder&
+    setDomainID(std::decay_t<typename SF_UINT256::type::value_type> const& value)
+    {
+        object_[sfDomainID] = value;
+        return *this;
+    }
+
     /**
      * @brief Build and return the LoanBrokerSet wrapper.
      * @param publicKey The public key for signing.

include/xrpl/tx/transactors/lending/LoanBrokerSet.h

@@ -22,6 +22,9 @@ class LoanBrokerSet : public Transactor
     static std::vector<OptionaledField<STNumber>> const&
     getValueFields();
 
+    static std::uint32_t
+    getFlagsMask(PreflightContext const& ctx);
+
     static TER
     preclaim(PreclaimContext const& ctx);
 

src/libxrpl/tx/invariants/InvariantCheck.cpp

@@ -979,7 +979,8 @@ NoModifiedUnmodifiableFields::finalize(
                     kFieldChanged(before, after, sfOwner) ||
                     kFieldChanged(before, after, sfManagementFeeRate) ||
                     kFieldChanged(before, after, sfCoverRateMinimum) ||
-                    kFieldChanged(before, after, sfCoverRateLiquidation);
+                    kFieldChanged(before, after, sfCoverRateLiquidation) ||
+                    kFieldChanged(before, after, sfFlags);
                 break;
             case ltLOAN:
                 /*

src/libxrpl/tx/invariants/LoanBrokerInvariant.cpp

@@ -140,6 +140,15 @@ ValidLoanBroker::finalize(
 
         auto const& before = broker.brokerBefore;
 
+        if (view.rules().enabled(featureLendingPermissionedDomain))
+        {
+            if (after->at(~sfDomainID) && !after->isFlag(lsfLoanBrokerPrivate))
+            {
+                JLOG(j.fatal()) << "Invariant failed: DomainID is set on public Loan Broker";
+                return false;
+            }
+        }
+
         // https://github.com/Tapanito/XRPL-Standards/blob/xls-66-lending-protocol/XLS-0066d-lending-protocol/README.md#3123-invariants
         // If `LoanBroker.OwnerCount = 0` the `DirectoryNode` will have at most
         // one node (the root), which will only hold entries for `RippleState`

src/libxrpl/tx/transactors/lending/LoanBrokerSet.cpp

@@ -9,17 +9,21 @@
 #include <xrpl/ledger/helpers/LendingHelpers.h>
 #include <xrpl/ledger/helpers/TokenHelpers.h>
 #include <xrpl/protocol/Asset.h>
+#include <xrpl/protocol/Feature.h>
 #include <xrpl/protocol/Indexes.h>
+#include <xrpl/protocol/LedgerFormats.h>
 #include <xrpl/protocol/Protocol.h>
 #include <xrpl/protocol/SField.h>
 #include <xrpl/protocol/STLedgerEntry.h>
 #include <xrpl/protocol/STNumber.h>
 #include <xrpl/protocol/STTakesAsset.h>
 #include <xrpl/protocol/STTx.h>
 #include <xrpl/protocol/TER.h>
+#include <xrpl/protocol/TxFlags.h>
 #include <xrpl/protocol/XRPAmount.h>
 #include <xrpl/tx/Transactor.h>
 
+#include <cstdint>
 #include <memory>
 #include <vector>
 
@@ -49,8 +53,17 @@ LoanBrokerSet::preflight(PreflightContext const& ctx)
     if (!validNumericRange(tx[~sfDebtMaximum], Number(kMaxMpTokenAmount), Number(0)))
         return temINVALID;
 
+    if (!ctx.rules.enabled(featureLendingPermissionedDomain))
+    {
+        if (tx.isFlag(tfLoanBrokerPrivate) || tx.isFieldPresent(sfDomainID))
+        {
+            return temDISABLED;
+        }
+    }
+
     if (tx.isFieldPresent(sfLoanBrokerID))
     {
+        // We're modifying an existing LoanBroker.
         // Fixed fields can not be specified if we're modifying an existing
         // LoanBroker Object
         if (tx.isFieldPresent(sfManagementFeeRate) || tx.isFieldPresent(sfCoverRateMinimum) ||
@@ -59,6 +72,36 @@ LoanBrokerSet::preflight(PreflightContext const& ctx)
 
         if (tx[sfLoanBrokerID] == beast::kZero)
             return temINVALID;
+
+        if (ctx.rules.enabled(featureLendingPermissionedDomain))
+        {
+            // Cannot change private flag on existing broker
+            if (tx.isFlag(tfLoanBrokerPrivate))
+            {
+                return temINVALID;
+            }
+        }
+    }
+    else
+    {
+        // We're creating a new LoanBroker.
+        if (ctx.rules.enabled(featureLendingPermissionedDomain))
+        {
+            auto const domainID = tx.at(~sfDomainID);
+            if (domainID)
+            {
+                if (*domainID == beast::kZero)
+                {
+                    // DomainID must not be zero if provided
+                    return temMALFORMED;
+                }
+                if (!tx.isFlag(tfLoanBrokerPrivate))
+                {
+                    // Public brokers cannot have a DomainID
+                    return temINVALID;
+                }
+            }
+        }
     }
 
     if (auto const vaultID = tx.at(~sfVaultID))
@@ -88,6 +131,16 @@ LoanBrokerSet::getValueFields()
     return kValueFields;
 }
 
+std::uint32_t
+LoanBrokerSet::getFlagsMask(PreflightContext const& ctx)
+{
+    if (ctx.rules.enabled(fixCleanup3_2_0))
+    {
+        return tfLoanBrokerSetMask;
+    }
+    return tfUniversalMask;
+}
+
 TER
 LoanBrokerSet::preclaim(PreclaimContext const& ctx)
 {
@@ -110,6 +163,20 @@ LoanBrokerSet::preclaim(PreclaimContext const& ctx)
         return tecNO_PERMISSION;
     }
 
+    if (ctx.view.rules().enabled(featureLendingPermissionedDomain))
+    {
+        auto const domainID = tx[~sfDomainID];
+        if (domainID && *domainID != beast::kZero)
+        {
+            auto const sleDomain = ctx.view.read(keylet::permissionedDomain(*domainID));
+            if (!sleDomain)
+            {
+                JLOG(ctx.j.warn()) << "Domain does not exist.";
+                return tecOBJECT_NOT_FOUND;
+            }
+        }
+    }
+
     if (auto const brokerID = tx[~sfLoanBrokerID])
     {
         // Updating an existing Broker
@@ -141,6 +208,13 @@ LoanBrokerSet::preclaim(PreclaimContext const& ctx)
                 return tecLIMIT_EXCEEDED;
             }
         }
+
+        if (ctx.view.rules().enabled(featureLendingPermissionedDomain))
+        {
+            auto const domainID = tx[~sfDomainID];
+            if (!sleBroker->isFlag(lsfLoanBrokerPrivate) && domainID)
+                return tecNO_PERMISSION;
+        }
     }
     else
     {
@@ -199,6 +273,22 @@ LoanBrokerSet::doApply()
         if (auto const debtMax = tx[~sfDebtMaximum])
             broker->at(sfDebtMaximum) = *debtMax;
 
+        if (ctx_.view().rules().enabled(featureLendingPermissionedDomain) &&
+            broker->isFlag(lsfLoanBrokerPrivate))
+        {
+            if (auto const domainID = tx[~sfDomainID])
+            {
+                if (*domainID != beast::kZero)
+                {
+                    broker->setFieldH256(sfDomainID, *domainID);
+                }
+                else if (broker->isFieldPresent(sfDomainID))
+                {
+                    broker->makeFieldAbsent(sfDomainID);
+                }
+            }
+        }
+
         view.update(broker);
 
         associateAsset(*broker, vaultAsset);
@@ -270,6 +360,16 @@ LoanBrokerSet::doApply()
         if (auto const coverLiq = tx[~sfCoverRateLiquidation])
             broker->at(sfCoverRateLiquidation) = *coverLiq;
 
+        if (ctx_.view().rules().enabled(featureLendingPermissionedDomain))
+        {
+            if (tx.isFlag(tfLoanBrokerPrivate))
+            {
+                broker->setFlag(lsfLoanBrokerPrivate);
+                if (auto domainID = tx[~sfDomainID])
+                    broker->setFieldH256(sfDomainID, *domainID);
+            }
+        }
+
         view.insert(broker);
 
         associateAsset(*broker, vaultAsset);