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pub use crate::proto::{AddFunds, SignInput};
use btc_transaction_utils::{p2wsh::InputSigner, TxInRef};
use exonum::runtime::{CommonError, ExecutionError, ExecutionFail};
use exonum_derive::{exonum_interface, interface_method};
use exonum_rust_runtime::ExecutionContext;
use log::{info, trace};
use crate::{btc, config::Config, BtcAnchoringService};
use super::{
data_layout::TxInputId,
errors::Error,
schema::{InputSignatures, Schema, TransactionConfirmations},
};
impl SignInput {
fn verify_signature(
&self,
input_signer: &InputSigner,
public_key: &btc::PublicKey,
proposal: &btc::Transaction,
inputs: &[btc::Transaction],
) -> Result<(), ExecutionError> {
let input_transaction = inputs.get(self.input as usize).ok_or(Error::NoSuchInput)?;
input_signer
.verify_input(
TxInRef::new(proposal.as_ref(), self.input as usize),
input_transaction.as_ref(),
&public_key.0,
self.input_signature.as_ref(),
)
.map_err(|e| Error::InputVerificationFailed.with_description(e))
}
}
impl InputSignatures {
fn len(&self) -> usize {
self.0.len()
}
fn insert(&mut self, id: u16, signature: btc::InputSignature) {
self.0.insert(id, signature);
}
fn values<'a>(
&'a self,
) -> impl IntoIterator<Item = btc_transaction_utils::InputSignature> + 'a {
self.0.values().map(|x| x.0.clone())
}
}
impl TransactionConfirmations {
fn confirm_by_node(&mut self, public_key: btc::PublicKey) {
self.0.insert(public_key, ());
}
pub(crate) fn has_enough_confirmations(&self, config: &Config) -> Result<bool, ExecutionError> {
let confirmations = self.0.len();
Ok(confirmations == config.byzantine_quorum())
}
}
#[exonum_interface]
pub trait BtcAnchoringInterface<Ctx> {
type Output;
#[interface_method(id = 0)]
fn sign_input(&self, context: Ctx, arg: SignInput) -> Self::Output;
#[interface_method(id = 1)]
fn add_funds(&self, context: Ctx, arg: AddFunds) -> Self::Output;
}
impl BtcAnchoringInterface<ExecutionContext<'_>> for BtcAnchoringService {
type Output = Result<(), ExecutionError>;
fn sign_input(&self, context: ExecutionContext<'_>, arg: SignInput) -> Self::Output {
let author = context
.caller()
.author()
.ok_or(CommonError::UnauthorizedCaller)?;
let mut schema = Schema::new(context.service_data());
let actual_config = schema.actual_config();
let (anchoring_node_id, public_key) = actual_config
.find_bitcoin_key(&author)
.ok_or(Error::UnauthorizedAnchoringKey)?;
let (proposal, expected_inputs) = if let Some(proposal) = schema
.actual_proposed_anchoring_transaction(context.data().for_core())
.transpose()
.map_err(Error::anchoring_builder_error)?
{
proposal
} else {
let latest_anchoring_txid = schema
.transactions_chain
.last()
.unwrap()
.id();
if latest_anchoring_txid == arg.txid {
return Ok(());
} else {
return Err(Error::UnexpectedProposalTxId.into());
}
};
if proposal.id() != arg.txid {
return Err(Error::UnexpectedProposalTxId.into());
}
let redeem_script = actual_config.redeem_script();
let quorum = redeem_script.content().quorum;
let input_signer = InputSigner::new(redeem_script);
arg.verify_signature(&input_signer, &public_key, &proposal, &expected_inputs)?;
let input_id = TxInputId::new(proposal.id(), arg.input);
let mut input_signatures = schema.input_signatures(&input_id);
let mut input_signature_len = input_signatures.len();
if input_signature_len < quorum {
input_signatures.insert(anchoring_node_id, arg.input_signature);
schema
.transaction_signatures
.put(&input_id, input_signatures);
input_signature_len += 1;
} else {
return Ok(());
}
if input_signature_len == quorum {
let mut finalized_tx: btc::Transaction = proposal.clone();
for index in 0..expected_inputs.len() {
let input_id = TxInputId::new(proposal.id(), index as u32);
let signatures_for_input = schema.input_signatures(&input_id);
if signatures_for_input.len() != quorum {
return Ok(());
}
input_signer.spend_input(
&mut finalized_tx.0.input[index],
signatures_for_input.values(),
);
}
let payload = finalized_tx.anchoring_metadata().unwrap().1;
info!("====== ANCHORING ======");
info!("txid: {}", finalized_tx.id().to_string());
info!("height: {}", payload.block_height);
info!("hash: {}", payload.block_hash.to_hex());
info!("balance: {}", finalized_tx.0.output[0].value);
trace!("Anchoring txhex: {}", finalized_tx.to_string());
schema.push_anchoring_transaction(finalized_tx);
}
Ok(())
}
fn add_funds(&self, context: ExecutionContext<'_>, arg: AddFunds) -> Self::Output {
let author = context
.caller()
.author()
.ok_or(CommonError::UnauthorizedCaller)?;
let mut schema = Schema::new(context.service_data());
let actual_config = schema.actual_config();
let (_, public_key) = actual_config
.find_bitcoin_key(&author)
.ok_or(Error::UnauthorizedAnchoringKey)?;
let (_, txout) = arg
.transaction
.find_out(&actual_config.anchoring_out_script())
.ok_or(Error::UnsuitableFundingTx)?;
let funding_txid = arg.transaction.id();
if schema.spent_funding_transactions.contains(&funding_txid) {
return Err(Error::AlreadyUsedFundingTx.into());
}
let mut confirmations = schema
.unconfirmed_funding_transactions
.get(&funding_txid)
.unwrap_or_default();
confirmations.confirm_by_node(public_key);
if confirmations.has_enough_confirmations(&actual_config)? {
info!("====== ADD_FUNDS ======");
info!("txid: {}", arg.transaction.id().to_string());
info!("balance: {}", txout.value);
schema.set_funding_transaction(arg.transaction);
} else {
schema
.unconfirmed_funding_transactions
.put(&funding_txid, confirmations);
}
Ok(())
}
}