[WIP] Define remaining transactions, start implementing LoanBrokerSet

- Does not build
- Transactions: LoanDelete, LoanManage, LoanDraw, LoanPay
- LoanBrokerSet creation mostly done. Need update.
- Also added a lookup table for pseudo account fields.

include/xrpl/protocol/Protocol.h

@@ -82,6 +82,26 @@ std::size_t constexpr maxDeletableTokenOfferEntries = 500;
  */
 std::uint16_t constexpr maxTransferFee = 50000;
 
+/** The maximum management fee rate allowed in lending.
+
+    TODO: Is this a good name?
+
+    Valid values for the the management fee charged by the Lending Protocol are
+    between 0 and 10000 inclusive. A value of 1 is equivalent to 1/10 basis
+    point fee or 0.001%.
+*/
+std::uint16_t constexpr maxFeeRate = 10'000;
+
+/** The maximum coverage rate allowed in lending.
+
+    TODO: Is this a good name?
+
+    Valid values for the coverage rate charged by the Lending Protocol for first
+    loss capital operations are between 0 and 100000 inclusive. A value of 1 is
+    equivalent to 1/10 bps or 0.001%.
+*/
+std::uint16_t constexpr maxCoverRate = 100'000;
+
 /** The maximum length of a URI inside an NFT */
 std::size_t constexpr maxTokenURILength = 256;
 

include/xrpl/protocol/TxFlags.h

@@ -237,6 +237,13 @@ constexpr std::uint32_t const tfVaultCreateMask = ~(tfUniversal | tfVaultPrivate
 // True, indicates the load supports overpayments
 constexpr std::uint32_t const tfLoanOverpayment = 0x00010000;
 constexpr std::uint32_t const tfLoanSetMask = ~(tfUniversal | tfLoanOverpayment);
+
+// LoanManage flags:
+constexpr std::uint32_t const tfLoanDefault = 0x00010000;
+constexpr std::uint32_t const tfLoanImpair = 0x00010000;
+constexpr std::uint32_t const tfLoanUnimpair = 0x00010000;
+constexpr std::uint32_t const tfLoanManageMask = ~(tfUniversal | tfLoanDefault | tfLoanImpair | tfLoanUnimpair);
+
 // clang-format on
 
 }  // namespace ripple

include/xrpl/protocol/detail/ledger_entries.macro

@@ -501,12 +501,12 @@ LEDGER_ENTRY(ltLOAN_BROKER, 0x0084, LoanBroker, loan_broker, ({
     {sfOwner,                soeREQUIRED},
     {sfData,                 soeDEFAULT},
     {sfManagementFeeRate,    soeDEFAULT},
-    {sfOwnerCount,           soeREQUIRED},
-    {sfDebtTotal,            soeREQUIRED},
-    {sfDebtMaximum,          soeREQUIRED},
-    {sfCoverAvailable,       soeREQUIRED},
-    {sfCoverRateMinimum,     soeREQUIRED},
-    {sfCoverRateLiquidation, soeREQUIRED},
+    {sfOwnerCount,           soeDEFAULT},
+    {sfDebtTotal,            soeDEFAULT},
+    {sfDebtMaximum,          soeDEFAULT},
+    {sfCoverAvailable,       soeDEFAULT},
+    {sfCoverRateMinimum,     soeDEFAULT},
+    {sfCoverRateLiquidation, soeDEFAULT},
 }))
 
 /** A ledger object representing a loan between a Borrower and a Loan Broker

include/xrpl/protocol/detail/sfields.macro

@@ -211,6 +211,7 @@ TYPED_SFIELD(sfHookSetTxnID,             UINT256,   33)
 TYPED_SFIELD(sfDomainID,                 UINT256,   34)
 TYPED_SFIELD(sfVaultID,                  UINT256,   35)
 TYPED_SFIELD(sfLoanBrokerID,             UINT256,   36)
+TYPED_SFIELD(sfLoanID,                   UINT256,   37)
 
 // number (common)
 TYPED_SFIELD(sfNumber,                   NUMBER,     1)

include/xrpl/protocol/detail/transactions.macro

@@ -508,7 +508,6 @@ TRANSACTION(ttVAULT_CLAWBACK, 69, VaultClawback, ({
     {sfAmount, soeOPTIONAL, soeMPTSupported},
 }))
 
-#if 0
 /** This transaction creates and updates a Loan Broker */
 TRANSACTION(ttLOAN_BROKER_SET, 70, LoanBrokerSet, ({
     {sfVaultID, soeREQUIRED},
@@ -520,6 +519,7 @@ TRANSACTION(ttLOAN_BROKER_SET, 70, LoanBrokerSet, ({
     {sfCoverRateLiquidation, soeDEFAULT},
 }))
 
+#if 0
 /** This transaction deletes a Loan Broker */
 TRANSACTION(ttLOAN_BROKER_DELETE, 71, LoanBrokerDelete, ({
     {sfLoanBrokerID, soeREQUIRED},
@@ -556,6 +556,28 @@ TRANSACTION(ttLOAN_SET, 74, LoanSet, ({
     {sfPaymentInterval, soeOPTIONAL},
     {sfGracePeriod, soeOPTIONAL},
 }))
+
+/** This transaction deletes an existing Loan */
+TRANSACTION(ttLOAN_DELETE, 75, LoanDelete, ({
+    {sfLoanID, soeREQUIRED},
+}))
+
+/** This transaction is used to change the delinquency status of an existing Loan */
+TRANSACTION(ttLOAN_MANAGE, 76, LoanManage, ({
+    {sfLoanID, soeREQUIRED},
+}))
+
+/** The Borrower uses this transaction to draws funds from the Loan. */
+TRANSACTION(ttLOAN_DRAW, 77, LoanDraw, ({
+    {sfLoanID, soeREQUIRED},
+    {sfAmount, soeREQUIRED},
+}))
+
+/** The Borrower uses this transaction to make a Payment on the Loan. */
+TRANSACTION(ttLOAN_PAY, 77, LoanPay, ({
+    {sfLoanID, soeREQUIRED},
+    {sfAmount, soeREQUIRED},
+}))
 #endif
 
 /** This system-generated transaction type is used to update the status of the various amendments.

src/xrpld/app/tx/detail/LoanBroker.cpp

@@ -0,0 +1,205 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2022 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <xrpld/app/tx/detail/LoanBroker.h>
+#include <xrpld/app/tx/detail/SignerEntries.h>
+#include <xrpld/app/tx/detail/Transactor.h>
+#include <xrpld/app/tx/detail/VaultCreate.h>
+#include <xrpld/ledger/ApplyView.h>
+#include <xrpld/ledger/View.h>
+
+#include <xrpl/basics/Log.h>
+#include <xrpl/basics/Number.h>
+#include <xrpl/basics/chrono.h>
+#include <xrpl/beast/utility/Journal.h>
+#include <xrpl/beast/utility/instrumentation.h>
+#include <xrpl/protocol/AccountID.h>
+#include <xrpl/protocol/Feature.h>
+#include <xrpl/protocol/Indexes.h>
+#include <xrpl/protocol/PublicKey.h>
+#include <xrpl/protocol/SField.h>
+#include <xrpl/protocol/STAmount.h>
+#include <xrpl/protocol/STObject.h>
+#include <xrpl/protocol/STXChainBridge.h>
+#include <xrpl/protocol/TER.h>
+#include <xrpl/protocol/TxFlags.h>
+#include <xrpl/protocol/XRPAmount.h>
+
+namespace ripple {
+
+bool
+lendingProtocolEnabled(PreflightContext const& ctx)
+{
+    return ctx.rules.enabled(featureLendingProtocol) &&
+        VaultCreate::isEnabled(ctx);
+}
+
+bool
+LoanBrokerSet::isEnabled(PreflightContext const& ctx)
+{
+    return lendingProtocolEnabled(ctx);
+}
+
+std::uint32_t
+LoanBrokerSet::getFlagsMask(PreflightContext const& ctx)
+{
+    return tfUniversalMask;
+}
+
+NotTEC
+LoanBrokerSet::doPreflight(PreflightContext const& ctx)
+{
+    auto const& tx = ctx.tx;
+    if (!validDataLength(tx[~sfData], maxDataPayloadLength))
+        return temINVALID;
+    if (!validNumericRange(tx[~sfManagementFeeRate], 0, maxFeeRate))
+        return temINVALID;
+    if (!validNumericRange(tx[~sfCoverRateMinimum], 0, maxCoverRate))
+        return temINVALID;
+    if (!validNumericRange(tx[~sfCoverRateLiquidation], 0, maxCoverRate))
+        return temINVALID;
+
+    if (tx.isFieldPresent(sfLoanBrokerID))
+    {
+        // Fixed fields can not be specified if we're modifying an existing
+        // LoanBroker Object
+        if (tx.isFieldPresent(sfManagementFeeRate) ||
+            tx.isFieldPresent(sfCoverRateMinimum) ||
+            tx.isFieldPresent(sfCoverRateLiquidation))
+            return temINVALID;
+    }
+
+    return tesSUCCESS;
+}
+
+TER
+LoanBrokerSet::preclaim(PreclaimContext const& ctx)
+{
+    auto const& tx = ctx.tx;
+
+    auto const account = tx[sfAccount];
+    if (auto const brokerID = tx[~sfLoanBrokerID])
+    {
+        auto const sleBroker = ctx.view.read(keylet::loanbroker(*brokerID));
+        if (!sleBroker)
+        {
+            JLOG(ctx.j.warn()) << "LoanBroker does not exist.";
+            return tecNO_ENTRY;
+        }
+        if (tx[sfVaultID] != sleBroker->at(sfVaultID))
+        {
+            JLOG(ctx.j.warn())
+                << "Can not change VaultID on an existing LoanBroker.";
+            return tecNO_PERMISSION;
+        }
+        if (account != sleBroker->at(sfOwner))
+        {
+            JLOG(ctx.j.warn()) << "Account is not the owner of the LoanBroker.";
+            return tecNO_PERMISSION;
+        }
+    }
+    else
+    {
+        auto const vaultID = tx[sfVaultID];
+        auto const sleVault = ctx.view.read(keylet::vault(vaultID));
+        if (!sleVault)
+        {
+            JLOG(ctx.j.warn()) << "Vault does not exist.";
+            return tecNO_ENTRY;
+        }
+        if (account != sleVault->at(sfOwner))
+        {
+            JLOG(ctx.j.warn()) << "Account is not the owner of the Vault.";
+            return tecNO_PERMISSION;
+        }
+    }
+    return tesSUCCESS;
+}
+
+TER
+LoanBrokerSet::doApply()
+{
+    auto const& tx = ctx_.tx;
+    auto& view = ctx_.view();
+
+    if (auto const brokerID = tx[~sfLoanBrokerID])
+    {
+        // Modify an existing LoanBroker
+        auto const sleBroker = view.read(keylet::loanbroker(*brokerID));
+
+        assert(0);
+    }
+    else
+    {
+        // Create a new LoanBroker pointing back to the given Vault
+        auto const vaultID = tx[sfVaultID];
+        auto const sleVault = view.read(keylet::vault(vaultID));
+        auto const vaultPseudoID = sleVault->at(sfAccount);
+        auto const sequence = tx.getSeqValue();
+
+        auto owner = view.peek(keylet::account(account_));
+        auto broker =
+            std::make_shared<SLE>(keylet::loanbroker(account_, sequence));
+
+        if (auto const ter = dirLink(view, account_, broker))
+            return ter;
+        if (auto const ter = dirLink(view, vaultPseudoID, broker))
+            return ter;
+
+        adjustOwnerCount(view, owner, 1, j_);
+        auto ownerCount = owner->at(sfOwnerCount);
+        if (mPriorBalance < view.fees().accountReserve(ownerCount))
+            return tecINSUFFICIENT_RESERVE;
+
+        auto maybePseudo = createPseudoAccount(
+            view, broker->key(), PseudoAccountOwnerType::LoanBroker);
+        if (!maybePseudo)
+            return maybePseudo.error();
+        auto& pseudo = *maybePseudo;
+        auto pseudoId = pseudo->at(sfAccount);
+
+        if (auto ter = addEmptyHolding(
+                view, pseudoId, mPriorBalance, sleVault->at(sfAsset), j_))
+            return ter;
+
+        // Initialize data fields:
+        broker->at(sfSequence) = sequence;
+        broker->at(sfVaultID) = vaultID;
+        broker->at(sfOwner) = account_;
+        broker->at(sfAccount) = pseudoId;
+        if (auto const data = tx[~sfData])
+            broker->at(sfData) = *data;
+        if (auto const rate = tx[~sfManagementFeeRate])
+            broker->at(sfManagementFeeRate) = *rate;
+        if (auto const debtMax = tx[~sfDebtMaximum]; debtMax && *debtMax)
+            broker->at(sfDebtMaximum) = *debtMax;
+        if (auto const coverMin = tx[~sfCoverRateMinimum])
+            broker->at(sfCoverRateMinimum) = *coverMin;
+        if (auto const coverLiq = tx[~sfCoverRateLiquidation])
+            broker->at(sfCoverRateLiquidation) = *coverLiq;
+
+        view.insert(broker);
+    }
+
+    return temDISABLED;
+}
+
+//------------------------------------------------------------------------------
+
+}  // namespace ripple

src/xrpld/app/tx/detail/LoanBroker.h

@@ -0,0 +1,60 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2022 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef RIPPLE_TX_LOANBROKER_H_INCLUDED
+#define RIPPLE_TX_LOANBROKER_H_INCLUDED
+
+#include <xrpld/app/tx/detail/Transactor.h>
+
+namespace ripple {
+
+// Lending protocol has dependencies, so capture them here.
+bool
+lendingProtocolEnabled(PreflightContext const& ctx);
+
+class LoanBrokerSet : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
+
+    explicit LoanBrokerSet(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static bool
+    isEnabled(PreflightContext const& ctx);
+
+    static std::uint32_t
+    getFlagsMask(PreflightContext const& ctx);
+
+    static NotTEC
+    doPreflight(PreflightContext const& ctx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+//------------------------------------------------------------------------------
+
+}  // namespace ripple
+
+#endif

src/xrpld/app/tx/detail/Transactor.cpp

@@ -205,6 +205,16 @@ Transactor::Transactor(ApplyContext& ctx)
 {
 }
 
+bool
+Transactor::validDataLength(
+    std::optional<Slice> const& slice,
+    std::size_t maxLength)
+{
+    if (!slice)
+        return true;
+    return !slice->empty() && slice->length() <= maxLength;
+}
+
 XRPAmount
 Transactor::calculateBaseFee(ReadView const& view, STTx const& tx)
 {

src/xrpld/app/tx/detail/Transactor.h

@@ -146,10 +146,6 @@ public:
     static XRPAmount
     calculateBaseFee(ReadView const& view, STTx const& tx);
 
-    // Base class always returns true
-    static bool
-    isEnabled(PreflightContext const& ctx);
-
     /* Do NOT define a preflight function in a derived class.
        Instead, define
 
@@ -212,6 +208,17 @@ protected:
         Fees const& fees,
         ApplyFlags flags);
 
+    // Base class always returns true
+    static bool
+    isEnabled(PreflightContext const& ctx);
+
+    static bool
+    validDataLength(std::optional<Slice> const& slice, std::size_t maxLength);
+
+    template <class T>
+    static bool
+    validNumericRange(std::optional<T> value, T min, T max);
+
 private:
     std::pair<TER, XRPAmount>
     reset(XRPAmount fee);
@@ -272,6 +279,15 @@ Transactor::preflight(PreflightContext const& ctx)
     return detail::preflight2(ctx);
 }
 
+template <class T>
+bool
+Transactor::validNumericRange(std::optional<T> value, T min, T max)
+{
+    if (!value)
+        return true;
+    return value >= min && value <= max;
+}
+
 }  // namespace ripple
 
 #endif

src/xrpld/app/tx/detail/VaultCreate.cpp

@@ -53,11 +53,8 @@ VaultCreate::getFlagsMask(PreflightContext const& ctx)
 NotTEC
 VaultCreate::doPreflight(PreflightContext const& ctx)
 {
-    if (auto const data = ctx.tx[~sfData])
-    {
-        if (data->empty() || data->length() > maxDataPayloadLength)
+    if (!validDataLength(ctx.tx[~sfData], maxDataPayloadLength))
         return temMALFORMED;
-    }
 
     if (auto const withdrawalPolicy = ctx.tx[~sfWithdrawalPolicy])
     {

src/xrpld/app/tx/detail/applySteps.cpp

@@ -41,6 +41,7 @@
 #include <xrpld/app/tx/detail/DepositPreauth.h>
 #include <xrpld/app/tx/detail/Escrow.h>
 #include <xrpld/app/tx/detail/LedgerStateFix.h>
+#include <xrpld/app/tx/detail/LoanBroker.h>
 #include <xrpld/app/tx/detail/MPTokenAuthorize.h>
 #include <xrpld/app/tx/detail/MPTokenIssuanceCreate.h>
 #include <xrpld/app/tx/detail/MPTokenIssuanceDestroy.h>