AMMClawback.cpp

//------------------------------------------------------------------------------
/*
  This file is part of rippled: https://github.com/ripple/rippled
  Copyright (c) 2024 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/misc/AMMHelpers.h>
#include <xrpld/app/misc/AMMUtils.h>
#include <xrpld/app/tx/detail/AMMClawback.h>
#include <xrpld/app/tx/detail/AMMWithdraw.h>
 
#include <xrpl/ledger/Sandbox.h>
#include <xrpl/ledger/View.h>
#include <xrpl/protocol/Feature.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/TxFlags.h>
#include <xrpl/protocol/st.h>
 
#include <tuple>
 
namespace ripple {
 
std::uint32_t
AMMClawback::getFlagsMask(PreflightContext const& ctx)
{
    return tfAMMClawbackMask;
}
 
NotTEC
AMMClawback::preflight(PreflightContext const& ctx)
{
    AccountID const issuer = ctx.tx[sfAccount];
    AccountID const holder = ctx.tx[sfHolder];
 
    if (issuer == holder)
    {
        JLOG(ctx.j.trace())
            << "AMMClawback: holder cannot be the same as issuer.";
        return temMALFORMED;
    }
 
    std::optional<STAmount> const clawAmount = ctx.tx[~sfAmount];
    auto const asset = ctx.tx[sfAsset].get<Issue>();
    auto const asset2 = ctx.tx[sfAsset2].get<Issue>();
 
    if (isXRP(asset))
        return temMALFORMED;
 
    auto const flags = ctx.tx.getFlags();
 
    if (flags & tfClawTwoAssets && asset.account != asset2.account)
    {
        JLOG(ctx.j.trace())
            << "AMMClawback: tfClawTwoAssets can only be enabled when two "
               "assets in the AMM pool are both issued by the issuer";
        return temINVALID_FLAG;
    }
 
    if (asset.account != issuer)
    {
        JLOG(ctx.j.trace()) << "AMMClawback: Asset's account does not "
                               "match Account field.";
        return temMALFORMED;
    }
 
    if (clawAmount && clawAmount->get<Issue>() != asset)
    {
        JLOG(ctx.j.trace()) << "AMMClawback: Amount's issuer/currency subfield "
                               "does not match Asset field";
        return temBAD_AMOUNT;
    }
 
    if (clawAmount && *clawAmount <= beast::zero)
        return temBAD_AMOUNT;
 
    return tesSUCCESS;
}
 
TER
AMMClawback::preclaim(PreclaimContext const& ctx)
{
    auto const asset = ctx.tx[sfAsset].get<Issue>();
    auto const asset2 = ctx.tx[sfAsset2].get<Issue>();
    auto const sleIssuer = ctx.view.read(keylet::account(ctx.tx[sfAccount]));
    if (!sleIssuer)
        return terNO_ACCOUNT;  // LCOV_EXCL_LINE
 
    if (!ctx.view.read(keylet::account(ctx.tx[sfHolder])))
        return terNO_ACCOUNT;
 
    auto const ammSle = ctx.view.read(keylet::amm(asset, asset2));
    if (!ammSle)
    {
        JLOG(ctx.j.debug()) << "AMM Clawback: Invalid asset pair.";
        return terNO_AMM;
    }
 
    std::uint32_t const issuerFlagsIn = sleIssuer->getFieldU32(sfFlags);
 
    // If AllowTrustLineClawback is not set or NoFreeze is set, return no
    // permission
    if (!(issuerFlagsIn & lsfAllowTrustLineClawback) ||
        (issuerFlagsIn & lsfNoFreeze))
        return tecNO_PERMISSION;
 
    return tesSUCCESS;
}
 
TER
AMMClawback::doApply()
{
    Sandbox sb(&ctx_.view());
 
    auto const ter = applyGuts(sb);
    if (ter == tesSUCCESS)
        sb.apply(ctx_.rawView());
 
    return ter;
}
 
TER
AMMClawback::applyGuts(Sandbox& sb)
{
    std::optional<STAmount> const clawAmount = ctx_.tx[~sfAmount];
    AccountID const issuer = ctx_.tx[sfAccount];
    AccountID const holder = ctx_.tx[sfHolder];
    Issue const asset = ctx_.tx[sfAsset].get<Issue>();
    Issue const asset2 = ctx_.tx[sfAsset2].get<Issue>();
 
    auto ammSle = sb.peek(keylet::amm(asset, asset2));
    if (!ammSle)
        return tecINTERNAL;  // LCOV_EXCL_LINE
 
    auto const ammAccount = (*ammSle)[sfAccount];
    auto const accountSle = sb.read(keylet::account(ammAccount));
    if (!accountSle)
        return tecINTERNAL;  // LCOV_EXCL_LINE
 
    if (sb.rules().enabled(fixAMMClawbackRounding))
    {
        // retrieve LP token balance inside the amendment gate to avoid
        // inconsistent error behavior
        auto const lpTokenBalance = ammLPHolds(sb, *ammSle, holder, j_);
        if (lpTokenBalance == beast::zero)
            return tecAMM_BALANCE;
 
        if (auto const res = verifyAndAdjustLPTokenBalance(
                sb, lpTokenBalance, ammSle, holder);
            !res)
            return res.error();  // LCOV_EXCL_LINE
    }
 
    auto const expected = ammHolds(
        sb,
        *ammSle,
        asset,
        asset2,
        FreezeHandling::fhIGNORE_FREEZE,
        ctx_.journal);
 
    if (!expected)
        return expected.error();  // LCOV_EXCL_LINE
    auto const [amountBalance, amount2Balance, lptAMMBalance] = *expected;
 
    TER result;
    STAmount newLPTokenBalance;
    STAmount amountWithdraw;
    std::optional<STAmount> amount2Withdraw;
 
    auto const holdLPtokens = ammLPHolds(sb, *ammSle, holder, j_);
    if (holdLPtokens == beast::zero)
        return tecAMM_BALANCE;
 
    if (!clawAmount)
        // Because we are doing a two-asset withdrawal,
        // tfee is actually not used, so pass tfee as 0.
        std::tie(result, newLPTokenBalance, amountWithdraw, amount2Withdraw) =
            AMMWithdraw::equalWithdrawTokens(
                sb,
                *ammSle,
                holder,
                ammAccount,
                amountBalance,
                amount2Balance,
                lptAMMBalance,
                holdLPtokens,
                holdLPtokens,
                0,
                FreezeHandling::fhIGNORE_FREEZE,
                WithdrawAll::Yes,
                mPriorBalance,
                ctx_.journal);
    else
        std::tie(result, newLPTokenBalance, amountWithdraw, amount2Withdraw) =
            equalWithdrawMatchingOneAmount(
                sb,
                *ammSle,
                holder,
                ammAccount,
                amountBalance,
                amount2Balance,
                lptAMMBalance,
                holdLPtokens,
                *clawAmount);
 
    if (result != tesSUCCESS)
        return result;  // LCOV_EXCL_LINE
 
    auto const res = AMMWithdraw::deleteAMMAccountIfEmpty(
        sb, ammSle, newLPTokenBalance, asset, asset2, j_);
    if (!res.second)
        return res.first;  // LCOV_EXCL_LINE
 
    JLOG(ctx_.journal.trace())
        << "AMM Withdraw during AMMClawback: lptoken new balance: "
        << to_string(newLPTokenBalance.iou())
        << " old balance: " << to_string(lptAMMBalance.iou());
 
    auto const ter = rippleCredit(sb, holder, issuer, amountWithdraw, true, j_);
    if (ter != tesSUCCESS)
        return ter;  // LCOV_EXCL_LINE
 
    // if the issuer issues both assets and sets flag tfClawTwoAssets, we
    // will claw the paired asset as well. We already checked if
    // tfClawTwoAssets is enabled, the two assets have to be issued by the
    // same issuer.
    if (!amount2Withdraw)
        return tecINTERNAL;  // LCOV_EXCL_LINE
 
    auto const flags = ctx_.tx.getFlags();
    if (flags & tfClawTwoAssets)
        return rippleCredit(sb, holder, issuer, *amount2Withdraw, true, j_);
 
    return tesSUCCESS;
}
 
std::tuple<TER, STAmount, STAmount, std::optional<STAmount>>
AMMClawback::equalWithdrawMatchingOneAmount(
    Sandbox& sb,
    SLE const& ammSle,
    AccountID const& holder,
    AccountID const& ammAccount,
    STAmount const& amountBalance,
    STAmount const& amount2Balance,
    STAmount const& lptAMMBalance,
    STAmount const& holdLPtokens,
    STAmount const& amount)
{
    auto frac = Number{amount} / amountBalance;
    auto amount2Withdraw = amount2Balance * frac;
 
    auto const lpTokensWithdraw =
        toSTAmount(lptAMMBalance.issue(), lptAMMBalance * frac);
 
    if (lpTokensWithdraw > holdLPtokens)
        // if lptoken balance less than what the issuer intended to clawback,
        // clawback all the tokens. Because we are doing a two-asset withdrawal,
        // tfee is actually not used, so pass tfee as 0.
        return AMMWithdraw::equalWithdrawTokens(
            sb,
            ammSle,
            holder,
            ammAccount,
            amountBalance,
            amount2Balance,
            lptAMMBalance,
            holdLPtokens,
            holdLPtokens,
            0,
            FreezeHandling::fhIGNORE_FREEZE,
            WithdrawAll::Yes,
            mPriorBalance,
            ctx_.journal);
 
    auto const& rules = sb.rules();
    if (rules.enabled(fixAMMClawbackRounding))
    {
        auto tokensAdj =
            getRoundedLPTokens(rules, lptAMMBalance, frac, IsDeposit::No);
 
        // LCOV_EXCL_START
        if (tokensAdj == beast::zero)
            return {
                tecAMM_INVALID_TOKENS, STAmount{}, STAmount{}, std::nullopt};
        // LCOV_EXCL_STOP
 
        frac = adjustFracByTokens(rules, lptAMMBalance, tokensAdj, frac);
        auto amount2Rounded =
            getRoundedAsset(rules, amount2Balance, frac, IsDeposit::No);
 
        auto amountRounded =
            getRoundedAsset(rules, amountBalance, frac, IsDeposit::No);
 
        return AMMWithdraw::withdraw(
            sb,
            ammSle,
            ammAccount,
            holder,
            amountBalance,
            amountRounded,
            amount2Rounded,
            lptAMMBalance,
            tokensAdj,
            0,
            FreezeHandling::fhIGNORE_FREEZE,
            WithdrawAll::No,
            mPriorBalance,
            ctx_.journal);
    }
 
    // Because we are doing a two-asset withdrawal,
    // tfee is actually not used, so pass tfee as 0.
    return AMMWithdraw::withdraw(
        sb,
        ammSle,
        ammAccount,
        holder,
        amountBalance,
        amount,
        toSTAmount(amount2Balance.issue(), amount2Withdraw),
        lptAMMBalance,
        toSTAmount(lptAMMBalance.issue(), lptAMMBalance * frac),
        0,
        FreezeHandling::fhIGNORE_FREEZE,
        WithdrawAll::No,
        mPriorBalance,
        ctx_.journal);
}
 
}  // namespace ripple