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.
Each validator will generate a random cookie on startup that it will
include in each of its validations. This will allow validators to detect
when more than one validator is accidentally operating with the same
validation keys.
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.
Introduce a new ledger type: ltCHECK
Introduce three new transactions that operate on checks:
- "CheckCreate" which adds the check entry to the ledger. The
check is a promise from the source of the check that the
destination of the check may cash the check and receive up to
the SendMax specified on the check. The check may have an
expiration, after which the check may no longer be cashed.
- "CheckCash" is a request by the destination of the check to
transfer a requested amount of funds, up to the check's SendMax,
from the source to the destination. The destination may receive
less than the SendMax due to transfer fees.
When cashing a check, the destination specifies the smallest
amount of funds that will be acceptable. If the transfer
completes and delivers the requested amount, then the check is
considered cashed and removed from the ledger. If enough funds
cannot be delivered, then the transaction fails and the check
remains in the ledger.
Attempting to cash the check after its expiration will fail.
- "CheckCancel" removes the check from the ledger without
transferring funds. Either the check's source or destination
can cancel the check at any time. After a check has expired,
any account can cancel the check.
Facilities related to checks are on the "Checks" amendment.
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.
Switches the default behavior of Consensus to use roundCloseTime instead of
effCloseTime. effCloseTime is still used when accepting the consensus ledger to
ensure the consensus close time comes after the parent ledger close time. This
change eliminates an edge case in which peers could reach agreement on the close
time, but end up generating ledgers with different close times.
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.
Sets a maximum TransferRate value of 100%. Squashes any
requested TransferRate over the limit to the max value.
This change requires an amendment ("fix1201") in rippled.
Adds test functionality for enabling an amendment mid-test.
Additionally, adds tests utilizing varying transfer rates both
with and without the amendment enabled.
This commit introduces the "SortedDirectories" amendment, which
addresses two distinct issues:
First, it corrects a technical flaw that could, in some edge cases,
prevent an empty intermediate page from being deleted.
Second, it sorts directory entries within a page (other than order
book page entries, which remain strictly FIFO). This makes insert
operations deterministic, instead of pseudo-random and reliant on
temporal ordering.
Lastly, it removes the ability to perform a "soft delete" where
the page number of the item to delete need not be known if the
item is in the first 20 pages, and enforces a maximum limit to
the number of pages that a directory can span.
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.
Replace Taker.cpp with calls to the payment flow() code.
This change required a number of tweaks in the payment flow code.
These tweaks are conditionalized on whether or not offer crossing
is taking place. The flag is explicitly passed as a parameter to
the flow code.
For testing, a class was added that identifies differences in the
contents of two PaymentSandboxes. That code may be reusable in
the future.
None of the Taker offer crossing code is removed. Both versions
of the code are co-resident to support an amendment cut-over.
The code that identifies differences between Taker and Flow offer
crossing is enabled by a feature. That makes it easy to enable
or disable difference logging by changing the config file. This
approach models what was done with the payment flow code. The
differencing code should never be enabled on a production server.
Extensive offer crossing unit tests are added to examine and
verify the behavior of corner cases. The tests are currently
configured to run against both Taker and Flow offer crossing.
This gives us confidence that most cases run identically and
some of the (few) differences in behavior are documented.
Add new functionality to enforce one or more sanity checks (invariants)
on transactions. Add tests for each new invariant check. Allow
for easily adding additional invariant checks in the future.
Also Resolves
-------------
- RIPD-1426
- RIPD-1427
- RIPD-1428
- RIPD-1429
- RIPD-1430
- RIPD-1431
- RIPD-1432
Release Notes
-------------
Creates a new ammendment named "EnforceInvariants" which must be
enabled in order for these new checks to run on each transaction.
* Sanity check on newly created strands
* Better loop detection
* Better tests (test every combination of path element pairs)
* Disallow any root issuer (even for xrp)
* Disallow compount element typs in path
* Issue was not reset when currency was XRP
* Add amendment
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.
The deferred credits table can compute a balance that's different from the
ledger balance.
Syntax:
A number written with no decimal means that number exactly. I.e. "12". A number
written with a decimal means that number has a non-zero digit at the lowest
order digit. I.e. "12.XX" means a number like "12.00000000000005"
Consider the following payment:
alice (USD) -> USD/XRP -> (XRP) Bob
Alice initially has 12.XX USD in her account.
The strand is used to debit alice the following amounts:
1) Debit alice 5
2) Debit alice 0.XX
3) Debit alice 3.XX
The next time the strand is explored, alice has a USD/XRP offer on the books,
and her account is credited:
1) Credit alice 20
When the beginning of the strand is reached, consider what happens when alice is
a limiting step. Calculate how much we can get out the step. According to the
deferred credit table this is:
12.XX - (5 + 0.XX + 3.XX)
This is also limited by alice's balance, which is large thanks to the credit she
received in the book step.
Now that the step has calculated how much we can get out, throw out the
sandbox (the one with the credit), and re-execute. However, the following error
occurs. We asked for 12.XX - (5 + 0.XX + 3.XX). However, the ledger has
calculated that alice has:
((12.XX - 5) - 0.XX) - 3.XX
That's a problem, because that number is smaller. Notice that there are two
precision losing operations in the deferred credits table:
1) The 5 + 0.XX step
2) The 12.XX - (total of debits). (Notice total of debits is < 10)
However, there is only one precision losing operation in the ledger calculation:
1) (Subtotal of 12.XX-5) - 0.XX
That means the calculation for the ledger results in a number that's smaller
than the deferred credits. Flow detects this as a re-execution error.
Add an amendment to allow gateways to set a "tick size"
for assets they issue. There are no changes unless the
amendment is enabled (since the tick size option cannot
be set).
With the amendment enabled:
AccountSet transactions may set a "TickSize" parameter.
Legal values are 0 and 3-15 inclusive. Zero removes the
setting. 3-15 allow that many decimal digits of precision
in the pricing of offers for assets issued by this account.
For asset pairs with XRP, the tick size imposed, if any,
is the tick size of the issuer of the non-XRP asset. For
asset pairs without XRP, the tick size imposed, if any,
is the smaller of the two issuer's configured tick sizes.
The tick size is imposed by rounding the offer quality
down to nearest tick and recomputing the non-critical
side of the offer. For a buy, the amount offered is
rounded down. For a sell, the amount charged is rounded up.
Gateways must enable a TickSize on their account for this
feature to benefit them.
The primary expected benefit is the elimination of bots
fighting over the tip of the order book. This means:
- Quicker price discovery as outpricing someone by a
microscopic amount is made impossible. Currently
bots can spend hours outbidding each other with no
significant price movement.
- A reduction in offer creation and cancellation spam.
- More offers left on the books as priority means
something when you can't outbid by a microscopic amount.
A conditional suspended payment is a suspended payment where
completion of the payment is contingent upon the fulfillment
of a condition defined by the sender during creation of the
suspended payment.
This commit also introduces the "CryptoConditions" amendment
which controls whether cryptoconditions will be supported
in suspended payments. The existing "SusPay" amendment can
be used to enable suspended payments without enabling the
cryptoconditions code.
The XRPEndpointStep bypassed the logic in deferred credits and
incorrectly counted funds acquired during a payment as available for
use in the payment. It also incorrectly used the current ownerCount when
calculating the reserve instead of the owner count as it was at the
beginning of the payment (reducing the owner count is analogous to
acquiring funds during a payment.)
Payment channels permit off-ledger checkpoints of XRP payments flowing
in a single direction. A channel sequesters the owner's XRP in its own
ledger entry. The owner can authorize the recipient to claim up to a
give balance by giving the receiver a signed message (off-ledger). The
recipient can use this signed message to claim any unpaid balance while
the channel remains open. The owner can top off the line as needed. If
the channel has not paid out all its funds, the owner must wait out a
delay to close the channel to give the recipient a chance to supply any
claims. The recipient can close the channel at any time. Any transaction
that touches the channel after the expiration time will close the
channel. The total amount paid increases monotonically as newer claims
are issued. When the channel is closed any remaining balance is returned
to the owner. Channels are intended to permit intermittent off-ledger
settlement of ILP trust lines as balances get substantial. For
bidirectional channels, a payment channel can be used in each direction.
Add a new algorithm for finding the liquidity in a payment path. There
is still a reverse and forward pass, but the forward pass starts at the
limiting step rather than the payment source. This insures the limiting
step is completely consumed rather than potentially leaving a 'dust'
amount in the forward pass.
Each step in a payment is either a book step, a direct step (account to
account step), or an xrp endpoint. Each step in the existing
implementation is a triple, where each element in the triple is either
an account of a book, for a total of eight step types.
Since accounts are considered in pairs, rather than triples, transfer
fees are handled differently. In V1 of payments, in the payment path
A -> gw ->B, if A redeems to gw, and gw issues to B, a transfer fee is
changed. In the new code, a transfer fee is changed even if A issues to
gw.
tapENABLE_TESTING is removed from checks, and feature enablement
is the sole method for activating features. Unit tests are updated
to enable required features in the construction of the Env.
Tickets are put on a feature switch instead of a build macro.
The first few transactions are added to the open ledger at
the base fee (ie. 10 drops). Once enough transactions are
added, the required fee will jump dramatically. If additional
transactions are added, the fee will grow exponentially.
Transactions that don't have a high enough fee to be applied to
the ledger are added to the queue in order from highest fee to
lowest. Whenever a new ledger is accepted as validated, transactions
are first applied from the queue to the open ledger in fee order
until either all transactions are applied or the fee again jumps
too high for the remaining transactions.
Current implementation is restricted to one transaction in the
queue per account. Some groundwork has been laid to expand in
the future.
Note that this fee logic escalates independently of the load-based
fee logic (ie. LoadFeeTrack). Submitted transactions must meet
the load fee to be considered for the queue, and must meet both
fees to be put into open ledger.
Eventually multisign will need to be enabled onto the network, at
which point compiling it in or out will no longer be an option.
In preparation, the compile guards are removed and multisign is
being enabled with a Feature.
You can locally enable a Feature using your config file. To
enable multisign with your config file add a section like this:
[features]
MultiSign
The exact spelling and capitalization of both "features" and
"MultiSign" is important. If you don't get those right multisign
will not be enabled.
There is a minor issue. The "sign_for" and "submit_multisigned"
RPC commands are only enabled if multisign is enabled. However
those commands are still shown in the help message even if
multisign is disabled. This is because the code that produces
the help message doesn't read the config file (where the Features
are kept). This problem will become irrelevant once multisign is
enabled onto the network.
This non-production config section allows features to be enabled
by listing their text descriptions, one line each, in the config
section titled "features".
NOTE: Feature names with leading or trailing whitespace, or
containing an equals sign ('=') are not supported.
