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feat: add end-of-block proposer payment (#38)
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@jacobkaufmann
jacobkaufmann authored Aug 13, 2023
1 parent 30bd6c8 commit 0686a37
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Showing 2 changed files with 120 additions and 17 deletions.
2 changes: 1 addition & 1 deletion Cargo.toml
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ version = "0.1.0"
edition = "2021"

[dependencies]
ethers = "2.0.8"
futures-util = "0.3.28"
reth-interfaces = { git = "https://github.com/paradigmxyz/reth.git", package = "reth-interfaces", version = "0.1.0-alpha.6" }
reth-payload-builder = { git = "https://github.com/paradigmxyz/reth.git", package = "reth-payload-builder", version = "0.1.0-alpha.6" }
Expand All @@ -21,6 +22,5 @@ revm = { git = "https://github.com/bluealloy/revm/", branch = "release/v25" }
revm-primitives = { git = "https://github.com/bluealloy/revm/", branch = "release/v25" }

[dev-dependencies]
ethers = "2.0.8"
rand = "0.8.5"
reth-provider = { git = "https://github.com/paradigmxyz/reth.git", package = "reth-provider", version = "0.1.0-alpha.6", features = ["test-utils"] }
135 changes: 119 additions & 16 deletions src/builder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,15 @@ use std::sync::{Arc, Mutex};
use std::task::{Context, Poll};
use std::time::{Duration, SystemTime, UNIX_EPOCH};

use ethers::{
signers::{LocalWallet, Signer},
types::{
transaction::{
eip1559::Eip1559TransactionRequest, eip2718::TypedTransaction, eip2930::AccessList,
},
Bytes as EthersBytes, NameOrAddress,
},
};
use futures_util::{stream::Fuse, FutureExt, Stream, StreamExt};
use reth_interfaces::Error as RethError;
use reth_payload_builder::{
Expand All @@ -15,8 +24,8 @@ use reth_payload_builder::{
};
use reth_primitives::{
constants::{BEACON_NONCE, EMPTY_OMMER_ROOT},
proofs, Block, BlockNumber, ChainSpec, Header, IntoRecoveredTransaction, Receipt, SealedBlock,
SealedHeader, TransactionSigned, TransactionSignedEcRecovered, U256,
proofs, Block, BlockNumber, Bytes, ChainSpec, Header, IntoRecoveredTransaction, Receipt,
SealedBlock, SealedHeader, TransactionSigned, TransactionSignedEcRecovered, U256,
};
use reth_provider::{
BlockReaderIdExt, CanonStateNotification, PostState, StateProvider, StateProviderFactory,
Expand Down Expand Up @@ -106,12 +115,18 @@ struct Payload {
bundles: HashSet<BundleId>,
}

#[derive(Clone, Debug)]
struct PayloadAttributes {
inner: PayloadBuilderAttributes,
extra_data: u128,
wallet: LocalWallet,
}

#[derive(Clone, Debug)]
struct JobConfig {
attributes: PayloadBuilderAttributes,
attributes: PayloadAttributes,
parent: Arc<SealedHeader>,
chain: Arc<ChainSpec>,
extra_data: u128,
}

/// a build job scoped to `config`
Expand Down Expand Up @@ -330,11 +345,18 @@ where
}
}

#[derive(Clone, Debug)]
pub struct BuilderConfig {
pub extra_data: u128,
pub wallet: LocalWallet,
}

pub struct Builder<Client, Pool> {
chain: Arc<ChainSpec>,
wallet: LocalWallet,
extra_data: u128,
client: Arc<Client>,
pool: Arc<Pool>,
extra_data: u128,
bundle_pool: Arc<Mutex<BundlePool>>,
incoming: broadcast::Sender<(BundleId, BlockNumber, BundleCompact)>,
invalidated: broadcast::Sender<BundleId>,
Expand All @@ -345,7 +367,7 @@ where
Client: StateProviderFactory + Unpin,
Pool: TransactionPool + Unpin,
{
pub fn new(chain: ChainSpec, extra_data: u128, client: Client, pool: Pool) -> Self {
pub fn new(config: BuilderConfig, chain: ChainSpec, client: Client, pool: Pool) -> Self {
let chain = Arc::new(chain);
let client = Arc::new(client);
let pool = Arc::new(pool);
Expand All @@ -357,9 +379,10 @@ where

Self {
chain,
wallet: config.wallet,
extra_data: config.extra_data,
client,
pool,
extra_data,
bundle_pool,
incoming,
invalidated,
Expand Down Expand Up @@ -451,12 +474,17 @@ where
)));
}

let attributes = PayloadAttributes {
inner: attributes,
extra_data: self.extra_data,
wallet: self.wallet.clone(),
};

let parent = Arc::new(latest.header.seal_slow());
let config = JobConfig {
chain: Arc::clone(&self.chain),
parent,
attributes,
extra_data: self.extra_data,
};

// collect eligible bundles from the pool
Expand Down Expand Up @@ -514,13 +542,22 @@ where

let mut post_state = PostState::default();

let (cfg_env, block_env) = config
let (cfg_env, mut block_env) = config
.attributes
.inner
.cfg_and_block_env(&config.chain, &config.parent);

// mark the builder as the coinbase in the block env
block_env.coinbase = config.attributes.wallet.address().into();

let block_num = block_env.number.to::<u64>();
let base_fee = block_env.basefee.to::<u64>();
let block_gas_limit: u64 = block_env.gas_limit.try_into().unwrap_or(u64::MAX);

// reserve gas for end-of-block proposer payment
const PROPOSER_PAYMENT_GAS_ALLOWANCE: u64 = 21000;
let execution_gas_limit = block_gas_limit - PROPOSER_PAYMENT_GAS_ALLOWANCE;

let mut coinbase_payment = U256::ZERO;
let mut cumulative_gas_used = 0;
let mut txs = Vec::new();
Expand All @@ -530,7 +567,7 @@ where
for (id, bundle) in bundles {
// check gas for entire bundle
let bundle_gas_limit: u64 = bundle.0.iter().map(|tx| tx.gas_limit()).sum();
if cumulative_gas_used + bundle_gas_limit > block_gas_limit {
if cumulative_gas_used + bundle_gas_limit > execution_gas_limit {
continue;
}

Expand Down Expand Up @@ -572,7 +609,7 @@ where
let mut mempool_txs = pool.best_transactions_with_base_fee(base_fee);
while let Some(tx) = mempool_txs.next() {
// check gas
if cumulative_gas_used + tx.gas_limit() > block_gas_limit {
if cumulative_gas_used + tx.gas_limit() > execution_gas_limit {
continue;
}

Expand Down Expand Up @@ -605,27 +642,63 @@ where
}
}

// construct payment to proposer fee recipient.
//
// NOTE: we give the entire coinbase payment to the proposer, except for the gas that we need
// to execute the transaction. if the coinbase payment cannot cover the gas cost to pay the
// proposer, then we do not make any payment.
let payment_tx_gas_cost = block_env.basefee * U256::from(PROPOSER_PAYMENT_GAS_ALLOWANCE);
let proposer_payment = coinbase_payment.saturating_sub(payment_tx_gas_cost);
if proposer_payment > U256::ZERO {
let builder_acct = db
.basic(block_env.coinbase)?
.expect("builder account exists if coinbase payment non-zero");
let payment_tx = proposer_payment_tx(
&config.attributes.wallet,
builder_acct.nonce,
base_fee,
cfg_env.chain_id.to::<u64>(),
&config.attributes.inner.suggested_fee_recipient,
proposer_payment,
);

// execute payment to proposer fee recipient
//
// if the payment transaction fails, then the entire payload build fails
let execution = execute(
&mut db,
&cfg_env,
&block_env,
cumulative_gas_used,
Some(payment_tx.clone()).into_iter(),
)
.map_err(PayloadBuilderError::EvmExecutionError)?;
cumulative_gas_used = execution.cumulative_gas_used;
txs.push(payment_tx);
post_state.extend(execution.post_state);
}

// NOTE: here we assume post-shanghai
let balance_increments = post_block_withdrawals_balance_increments(
&config.chain,
config.attributes.timestamp,
&config.attributes.withdrawals,
config.attributes.inner.timestamp,
&config.attributes.inner.withdrawals,
);
for (address, increment) in balance_increments {
increment_account_balance(&mut db, &mut post_state, block_num, address, increment)?;
}

let block = package_block(
state.state(),
&config.attributes,
config.extra_data,
&config.attributes.inner,
config.attributes.extra_data,
&block_env,
txs.into_iter().map(|tx| tx.into_signed()).collect(),
post_state,
cumulative_gas_used,
)?;

let payload = BuiltPayload::new(config.attributes.id, block, coinbase_payment);
let payload = BuiltPayload::new(config.attributes.inner.id, block, proposer_payment);
let payload = Payload {
inner: Arc::new(payload),
bundles: bundle_ids,
Expand Down Expand Up @@ -769,6 +842,36 @@ fn compute_coinbase_payment(
}
}

/// Constructs a transfer transaction to pay `amount` to `proposer`.
fn proposer_payment_tx(
wallet: &LocalWallet,
nonce: u64,
base_fee: u64,
chain_id: u64,
proposer: &B160,
amount: U256,
) -> TransactionSignedEcRecovered {
let tx = Eip1559TransactionRequest::new()
.from(wallet.address())
.to(NameOrAddress::Address(ethers::types::H160::from_slice(
proposer.as_bytes(),
)))
.gas(21000)
.max_fee_per_gas(base_fee)
.max_priority_fee_per_gas(0)
.value(amount)
.data(EthersBytes::default())
.access_list(AccessList::default())
.nonce(nonce)
.chain_id(chain_id);
let tx = TypedTransaction::Eip1559(tx);
let signature = wallet.sign_transaction_sync(&tx).expect("can sign tx");
let tx_encoded = tx.rlp_signed(&signature);
let tx = TransactionSigned::decode_enveloped(Bytes::from(tx_encoded.as_ref()))
.expect("can decode tx");
tx.into_ecrecovered().expect("can recover tx signer")
}

#[cfg(test)]
mod tests {
use super::*;
Expand Down

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