148 lines
4.6 KiB
Rust
148 lines
4.6 KiB
Rust
use super::errors::{TransferInvalid as Invalid, TransferValidationError as Error};
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use bls::get_withdrawal_credentials;
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use ssz::SignedRoot;
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use types::*;
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/// Indicates if a `Transfer` is valid to be included in a block in the current epoch of the given
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/// state.
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///
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/// Returns `Ok(())` if the `Transfer` is valid, otherwise indicates the reason for invalidity.
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///
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/// Note: this function is incomplete.
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///
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/// Spec v0.5.0
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pub fn verify_transfer(
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state: &BeaconState,
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transfer: &Transfer,
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spec: &ChainSpec,
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) -> Result<(), Error> {
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let sender_balance = *state
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.validator_balances
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.get(transfer.sender as usize)
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.ok_or_else(|| Error::Invalid(Invalid::FromValidatorUnknown(transfer.sender)))?;
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let total_amount = transfer
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.amount
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.checked_add(transfer.fee)
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.ok_or_else(|| Error::Invalid(Invalid::FeeOverflow(transfer.amount, transfer.fee)))?;
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verify!(
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sender_balance >= transfer.amount,
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Invalid::FromBalanceInsufficient(transfer.amount, sender_balance)
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);
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verify!(
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sender_balance >= transfer.fee,
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Invalid::FromBalanceInsufficient(transfer.fee, sender_balance)
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);
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verify!(
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(sender_balance == total_amount)
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|| (sender_balance >= (total_amount + spec.min_deposit_amount)),
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Invalid::InvalidResultingFromBalance(
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sender_balance - total_amount,
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spec.min_deposit_amount
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)
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);
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verify!(
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state.slot == transfer.slot,
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Invalid::StateSlotMismatch(state.slot, transfer.slot)
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);
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let sender_validator = state
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.validator_registry
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.get(transfer.sender as usize)
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.ok_or_else(|| Error::Invalid(Invalid::FromValidatorUnknown(transfer.sender)))?;
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let epoch = state.slot.epoch(spec.slots_per_epoch);
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verify!(
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sender_validator.is_withdrawable_at(epoch)
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|| sender_validator.activation_epoch == spec.far_future_epoch,
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Invalid::FromValidatorIneligableForTransfer(transfer.sender)
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);
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let transfer_withdrawal_credentials = Hash256::from_slice(
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&get_withdrawal_credentials(&transfer.pubkey, spec.bls_withdrawal_prefix_byte)[..],
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);
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verify!(
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sender_validator.withdrawal_credentials == transfer_withdrawal_credentials,
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Invalid::WithdrawalCredentialsMismatch(
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sender_validator.withdrawal_credentials,
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transfer_withdrawal_credentials
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)
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);
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let message = transfer.signed_root();
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let domain = spec.get_domain(
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transfer.slot.epoch(spec.slots_per_epoch),
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Domain::Transfer,
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&state.fork,
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);
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verify!(
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transfer
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.signature
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.verify(&message[..], domain, &transfer.pubkey),
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Invalid::BadSignature
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);
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Ok(())
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}
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/// Executes a transfer on the state.
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///
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/// Does not check that the transfer is valid, however checks for overflow in all actions.
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///
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/// Spec v0.5.0
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pub fn execute_transfer(
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state: &mut BeaconState,
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transfer: &Transfer,
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spec: &ChainSpec,
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) -> Result<(), Error> {
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let sender_balance = *state
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.validator_balances
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.get(transfer.sender as usize)
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.ok_or_else(|| Error::Invalid(Invalid::FromValidatorUnknown(transfer.sender)))?;
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let recipient_balance = *state
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.validator_balances
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.get(transfer.recipient as usize)
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.ok_or_else(|| Error::Invalid(Invalid::ToValidatorUnknown(transfer.recipient)))?;
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let proposer_index =
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state.get_beacon_proposer_index(state.slot, RelativeEpoch::Current, spec)?;
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let proposer_balance = state.validator_balances[proposer_index];
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let total_amount = transfer
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.amount
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.checked_add(transfer.fee)
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.ok_or_else(|| Error::Invalid(Invalid::FeeOverflow(transfer.amount, transfer.fee)))?;
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state.validator_balances[transfer.sender as usize] =
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sender_balance.checked_sub(total_amount).ok_or_else(|| {
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Error::Invalid(Invalid::FromBalanceInsufficient(
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total_amount,
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sender_balance,
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))
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})?;
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state.validator_balances[transfer.recipient as usize] = recipient_balance
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.checked_add(transfer.amount)
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.ok_or_else(|| {
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Error::Invalid(Invalid::ToBalanceOverflow(
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recipient_balance,
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transfer.amount,
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))
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})?;
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state.validator_balances[proposer_index] =
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proposer_balance.checked_add(transfer.fee).ok_or_else(|| {
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Error::Invalid(Invalid::ProposerBalanceOverflow(
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proposer_balance,
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transfer.fee,
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))
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})?;
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Ok(())
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}
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