PaymentChannelClaim.cpp

#include <xrpl/ledger/ApplyView.h>
#include <xrpl/ledger/View.h>
#include <xrpl/ledger/helpers/CredentialHelpers.h>
#include <xrpl/protocol/Feature.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/PayChan.h>
#include <xrpl/protocol/PublicKey.h>
#include <xrpl/protocol/TxFlags.h>
#include <xrpl/tx/transactors/payment_channel/PaymentChannelClaim.h>
 
#include <libxrpl/tx/transactors/payment_channel/PaymentChannelHelpers.h>
 
namespace xrpl {
 
bool
PaymentChannelClaim::checkExtraFeatures(PreflightContext const& ctx)
{
    return !ctx.tx.isFieldPresent(sfCredentialIDs) || ctx.rules.enabled(featureCredentials);
}
 
std::uint32_t
PaymentChannelClaim::getFlagsMask(PreflightContext const&)
{
    return tfPaymentChannelClaimMask;
}
 
NotTEC
PaymentChannelClaim::preflight(PreflightContext const& ctx)
{
    auto const bal = ctx.tx[~sfBalance];
    if (bal && (!isXRP(*bal) || *bal <= beast::zero))
        return temBAD_AMOUNT;
 
    auto const amt = ctx.tx[~sfAmount];
    if (amt && (!isXRP(*amt) || *amt <= beast::zero))
        return temBAD_AMOUNT;
 
    if (bal && amt && *bal > *amt)
        return temBAD_AMOUNT;
 
    {
        auto const flags = ctx.tx.getFlags();
 
        if (((flags & tfClose) != 0u) && ((flags & tfRenew) != 0u))
            return temMALFORMED;
    }
 
    if (auto const sig = ctx.tx[~sfSignature])
    {
        if (!(ctx.tx[~sfPublicKey] && bal))
            return temMALFORMED;
 
        // Check the signature
        // The signature isn't needed if txAccount == src, but if it's
        // present, check it
 
        auto const reqBalance = bal->xrp();
        auto const authAmt = amt ? amt->xrp() : reqBalance;
 
        if (reqBalance > authAmt)
            return temBAD_AMOUNT;
 
        Keylet const k(ltPAYCHAN, ctx.tx[sfChannel]);
        if (!publicKeyType(ctx.tx[sfPublicKey]))
            return temMALFORMED;
 
        PublicKey const pk(ctx.tx[sfPublicKey]);
        Serializer msg;
        serializePayChanAuthorization(msg, k.key, authAmt);
        if (!verify(pk, msg.slice(), *sig))
            return temBAD_SIGNATURE;
    }
 
    if (auto const err = credentials::checkFields(ctx.tx, ctx.j); !isTesSuccess(err))
        return err;
 
    return tesSUCCESS;
}
 
TER
PaymentChannelClaim::preclaim(PreclaimContext const& ctx)
{
    if (!ctx.view.rules().enabled(featureCredentials))
        return Transactor::preclaim(ctx);
 
    if (auto const err = credentials::valid(ctx.tx, ctx.view, ctx.tx[sfAccount], ctx.j);
        !isTesSuccess(err))
        return err;
 
    return tesSUCCESS;
}
 
TER
PaymentChannelClaim::doApply()
{
    Keylet const k(ltPAYCHAN, ctx_.tx[sfChannel]);
    auto const slep = ctx_.view().peek(k);
    if (!slep)
        return tecNO_TARGET;
 
    AccountID const src = (*slep)[sfAccount];
    AccountID const dst = (*slep)[sfDestination];
    AccountID const txAccount = ctx_.tx[sfAccount];
 
    auto const curExpiration = (*slep)[~sfExpiration];
    {
        auto const cancelAfter = (*slep)[~sfCancelAfter];
        auto const closeTime = ctx_.view().header().parentCloseTime.time_since_epoch().count();
        if ((cancelAfter && closeTime >= *cancelAfter) ||
            (curExpiration && closeTime >= *curExpiration))
            return closeChannel(slep, ctx_.view(), k.key, ctx_.registry.get().getJournal("View"));
    }
 
    if (txAccount != src && txAccount != dst)
        return tecNO_PERMISSION;
 
    if (ctx_.tx[~sfBalance])
    {
        auto const chanBalance = slep->getFieldAmount(sfBalance).xrp();
        auto const chanFunds = slep->getFieldAmount(sfAmount).xrp();
        auto const reqBalance = ctx_.tx[sfBalance].xrp();
 
        if (txAccount == dst && !ctx_.tx[~sfSignature])
            return temBAD_SIGNATURE;
 
        if (ctx_.tx[~sfSignature])
        {
            PublicKey const pk((*slep)[sfPublicKey]);
            if (ctx_.tx[sfPublicKey] != pk)
                return temBAD_SIGNER;
        }
 
        if (reqBalance > chanFunds)
            return tecUNFUNDED_PAYMENT;
 
        if (reqBalance <= chanBalance)
        {
            // nothing requested
            return tecUNFUNDED_PAYMENT;
        }
 
        auto const sled = ctx_.view().peek(keylet::account(dst));
        if (!sled)
            return tecNO_DST;
 
        if (auto err =
                verifyDepositPreauth(ctx_.tx, ctx_.view(), txAccount, dst, sled, ctx_.journal);
            !isTesSuccess(err))
            return err;
 
        (*slep)[sfBalance] = ctx_.tx[sfBalance];
        XRPAmount const reqDelta = reqBalance - chanBalance;
        XRPL_ASSERT(
            reqDelta >= beast::zero, "xrpl::PaymentChannelClaim::doApply : minimum balance delta");
        (*sled)[sfBalance] = (*sled)[sfBalance] + reqDelta;
        ctx_.view().update(sled);
        ctx_.view().update(slep);
    }
 
    if ((ctx_.tx.getFlags() & tfRenew) != 0u)
    {
        if (src != txAccount)
            return tecNO_PERMISSION;
        (*slep)[~sfExpiration] = std::nullopt;
        ctx_.view().update(slep);
    }
 
    if ((ctx_.tx.getFlags() & tfClose) != 0u)
    {
        // Channel will close immediately if dry or the receiver closes
        if (dst == txAccount || (*slep)[sfBalance] == (*slep)[sfAmount])
            return closeChannel(slep, ctx_.view(), k.key, ctx_.registry.get().getJournal("View"));
 
        auto const settleExpiration =
            ctx_.view().header().parentCloseTime.time_since_epoch().count() +
            (*slep)[sfSettleDelay];
 
        if (!curExpiration || *curExpiration > settleExpiration)
        {
            (*slep)[~sfExpiration] = settleExpiration;
            ctx_.view().update(slep);
        }
    }
 
    return tesSUCCESS;
}
 
}  // namespace xrpl