When an AMM account is deleted, the owner directory entries must be
deleted in order to ensure consistent ledger state.
* When deleting AMM account:
* Clean up AMM owner dir, linking AMM account and AMM object
* Delete trust lines to AMM
* Disallow `CheckCreate` to AMM accounts
* AMM cannot cash a check
* Constrain entries in AuthAccounts array to be accounts
* AuthAccounts is an array of objects for the AMMBid transaction
* SetTrust (TrustSet): Allow on AMM only for LP tokens
* If the destination is an AMM account and the trust line doesn't
exist, then:
* If the asset is not the AMM LP token, then fail the tx with
`tecNO_PERMISSION`
* If the AMM is in empty state, then fail the tx with `tecAMM_EMPTY`
* This disallows trustlines to AMM in empty state
* Add AMMID to AMM root account
* Remove lsfAMM flag and use sfAMMID instead
* Remove owner dir entry for ltAMM
* Add `AMMDelete` transaction type to handle amortized deletion
* Limit number of trust lines to delete on final withdraw + AMMDelete
* Put AMM in empty state when LPTokens is 0 upon final withdraw
* Add `tfTwoAssetIfEmpty` deposit option in AMM empty state
* Fail all AMM transactions in AMM empty state except special deposit
* Add `tecINCOMPLETE` to indicate that not all AMM trust lines are
deleted (i.e. partial deletion)
* This is handled in Transactor similar to deleted offers
* Fail AMMDelete with `tecINTERNAL` if AMM root account is nullptr
* Don't validate for invalid asset pair in AMMDelete
* AMMWithdraw deletes AMM trust lines and AMM account/object only if the
number of trust lines is less than max
* Current `maxDeletableAMMTrustLines` = 512
* Check no directory left after AMM trust lines are deleted
* Enable partial trustline deletion in AMMWithdraw
* Add `tecAMM_NOT_EMPTY` to fail any transaction that expects an AMM in
empty state
* Clawback considerations
* Disallow clawback out of AMM account
* Disallow AMM create if issuer can claw back
This patch applies to the AMM implementation in #4294.
Acknowledgements:
Richard Holland and Nik Bougalis for responsibly disclosing this issue.
Bug Bounties and Responsible Disclosures:
We welcome reviews of the project code and urge researchers to
responsibly disclose any issues they may find.
To report a bug, please send a detailed report to:
bugs@xrpl.org
Signed-off-by: Manoj Doshi <mdoshi@ripple.com>
Add AMM functionality:
- InstanceCreate
- Deposit
- Withdraw
- Governance
- Auctioning
- payment engine integration
To support this functionality, add:
- New RPC method, `amm_info`, to fetch pool and LPT balances
- AMM Root Account
- trust line for each IOU AMM token
- trust line to track Liquidity Provider Tokens (LPT)
- `ltAMM` object
The `ltAMM` object tracks:
- fee votes
- auction slot bids
- AMM tokens pair
- total outstanding tokens balance
- `AMMID` to AMM `RootAccountID` mapping
Add new classes to facilitate AMM integration into the payment engine.
`BookStep` uses these classes to infer if AMM liquidity can be consumed.
The AMM formula implementation uses the new Number class added in #4192.
IOUAmount and STAmount use Number arithmetic.
Add AMM unit tests for all features.
AMM requires the following amendments:
- featureAMM
- fixUniversalNumber
- featureFlowCross
Notes:
- Current trading fee threshold is 1%
- AMM currency is generated by: 0x03 + 152 bits of sha256{cur1, cur2}
- Current max AMM Offers is 30
---------
Co-authored-by: Howard Hinnant <howard.hinnant@gmail.com>
Support for 'out-of-sequence' transaction execution was introduced
in commit 7724cca384.
The changes in that commit were gated under a feature but there was
no corresponding amendment introduced that would allow the network
to vote on this amendment.
This commit introduces 'TicketBatch' amendment as the amendment
that is associated with the tickets feature. If the amendment is
enabled, it will activate support for tickets.
This commit also removes several workarounds that are no longer
needed in unit tests.
Tickets are a mechanism to allow for the "out-of-order" execution of
transactions on the XRP Ledger.
This commit, if merged, reworks the existing support for tickets and
introduces support for 'ticket batching', completing the feature set
needed for tickets.
The code is gated under the newly-introduced `TicketBatch` amendment
and the `Tickets` amendment, which is not presently active on the
network, is being removed.
The specification for this change can be found at:
https://github.com/xrp-community/standards-drafts/issues/16
The XRP Ledger utilizes an account model. Unlike systems based on a UTXO
model, XRP Ledger accounts are first-class objects. This design choice
allows the XRP Ledger to offer rich functionality, including the ability
to own objects (offers, escrows, checks, signer lists) as well as other
advanced features, such as key rotation and configurable multi-signing
without needing to change a destination address.
The trade-off is that accounts must be stored on ledger. The XRP Ledger
applies reserve requirements, in XRP, to protect the shared global ledger
from growing excessively large as the result of spam or malicious usage.
Prior to this commit, accounts had been permanent objects; once created,
they could never be deleted.
This commit introduces a new amendment "DeletableAccounts" which, if
enabled, will allow account objects to be deleted by executing the new
"AccountDelete" transaction. Any funds remaining in the account will
be transferred to an account specified in the deletion transaction.
The amendment changes the mechanics of account creation; previously
a new account would have an initial sequence number of 1. Accounts
created after the amendment will have an initial sequence number that
is equal to the ledger in which the account was created.
Accounts can only be deleted if they are not associated with any
obligations (like RippleStates, Escrows, or PayChannels) and if the
current ledger sequence number exceeds the account's sequence number
by at least 256 so that, if recreated, the account can be protected
from transaction replay.
At this point all of the jss::* names are defined in the same
file. That file has been named JsonFields.h. That file name
has little to do with either JsonStaticStrings (which is what
jss is short for) or with jss. The file is renamed to jss.h
so the file name better reflects what the file contains.
All includes of that file are fixed. A few include order
issues are tidied up along the way.
The lsfDepositAuth flag limits the AccountIDs that can deposit into
the account that has the flag set. The original design only
allowed deposits to complete if the account with the flag set also
signed the transaction that caused the deposit.
The DepositPreauth ledger type allows an account with the
lsfDepositAuth flag set to preauthorize additional accounts.
This preauthorization allows them to sign deposits as well. An
account can add DepositPreauth objects to the ledger (and remove
them as well) using the DepositPreauth transaction.
The six different ranges of TER codes are broken up into six
different enumerations. A template class allows subsets of
these enumerations to be aggregated. This technique allows
verification at compile time that no TEC codes are returned
before the signature is checked.
Conversion between TER instance and integer is provided by
named functions. This makes accidental conversion almost
impossible and makes type abuse easier to spot in the code
base.
When creating an escrow, if the `CancelAfter` time is specified but
the `FinishAfter` is not, the resulting escrow can be immediately
completed using `EscrowFinish`. While this behavior is documented,
it is unintuitive and can be confusing for users.
This commit introduces a new fix amendment (fix1571) which prevents
the creation of new Escrow entries that can be finished immediately
and without any requirements.
Once the amendment is activated, creating a new Escrow will require
specifying the `FinishAfter` time explicitly or requires that a
cryptocondition be specified.
The DepositAuth feature allows an account to require that
it signs for any funds that are deposited to the account.
For the time being this limits the account to accepting
only XRP, although there are plans to allow IOU payments
in the future.
The lsfDepositAuth protections are not extended to offers.
If an account creates an offer it is in effect saying, “I
will accept funds from anyone who takes this offer.”
Therefore, the typical user of the lsfDepositAuth flag
will choose never to create any offers. But they can if
they so choose.
The DepositAuth feature leaves a small gap in its
protections. An XRP payment is allowed to a destination
account with the lsfDepositAuth flag set if:
- The Destination XRP balance is less than or equal to
the base reserve and
- The value of the XRP Payment is less than or equal to
the base reserve.
This exception is intended to make it impossible for an
account to wedge itself by spending all of its XRP on fees
and leave itself unable to pay the fee to get more XRP.
This commit
- adds featureDepositAuth,
- adds the lsfDepositAuth flag,
- adds support for lsfDepositAuth in SetAccount.cpp
- adds support in Payment.cpp for rejecting payments that
don't meet the lsfDepositAuth requirements,
- adds unit tests for Payment transactions to an an account
with lsfDepositAuth set.
- adds Escrow and PayChan support for lsfDepositAuth along
with as unit tests.
* Remove composite helper functions
* Add set difference and Bitset/uint256 operators
* Convert tests to use new feature bitset set difference operator
In order to automatically run unit tests with newly created
amendments, prefer to start with jtx::supported_features() and
then subtract unwanted features.
These changes identified a few bugs that were hiding in
amendments. One of those bugs, in FlowCross, is not yet fixed.
By uncommenting the test in CrossingLimits_test.cpp you can see
failures relating to that bug. Since FlowCross is not yet
enabled on the network we can fix the bug at our convenience.
Both Tickets and SHAMapV2 have been around for a while and don't
look like they will be enabled on the network soon. So they are
removed from the supportedAmendments list. This prevents Env
from automatically testing with Tickets or SHAMapV2 enabled,
although testing with those features can still be explicitly
specified.
Drive-by cleanups:
o supportedAmendments() returns a const reference rather than
a fresh vector on each call.
o supportedAmendments() implementation moved from Amendments.cpp
to Feature.cpp. Amendments.cpp deleted.
o supportedAmendments() declared in Feature.h. All other
declarations deleted.
o preEnabledAmendments() removed, since it was empty and only
used in one place. It will be easy to re-add when it is needed.
o jtx::all_features_except() renamed to
jtx::supported_features_except(), which is more descriptive.
o jtx::all_amendments() renamed to jxt::supported_amendments()
o jtx::with_features() renamed to with_only_features()
o Env_test.cpp adjusted since featureTickets is no longer
automatically enabled for unit tests.
Introduce "fix1523" which corrects a minor technical flaw with
the original implementation of the escrow feature.
When creating an escrow, the entry would only be tracked in the
owner directory of the sender; as a result, an escrow recipient
would not be able to detect incoming escrows without monitoring
the ledger in real-time for transactions of interest or without
the sender communicating this information out of band.
With the fix in place, escrows where the recipient differs from
the sender will be listed in the recipient's owner directory as
well.
Enable all supported amendments in Env by default. Rename `features()`
to `with_features()` and add `all_features_except()` to support feature
subsets in Env. Refactor internal feature handling based on a bitset.
Escrow replaces the existing SusPay implementation with improved
code that also adds hashlock support to escrow payments, making
RCL ILP enabled.
The new functionality is under the `Escrow` amendment, which
supersedes and replaces the `SusPay` amendment.
This commit also deprecates the `CryptoConditions` amendment
which is replaced by the `CryptoConditionSuite` amendment which,
once enabled, will allow use of cryptoconditions others than
hashlocks.
