Smart Contract Scheduler

.github/workflows/tests.yml

@@ -48,6 +48,7 @@ jobs:
             -p serai-processor-utxo-scheduler-primitives \
             -p serai-processor-utxo-scheduler \
             -p serai-processor-transaction-chaining-scheduler \
+            -p serai-processor-smart-contract-scheduler \
             -p serai-processor-signers \
             -p serai-processor-bin \
             -p serai-bitcoin-processor \

Cargo.lock

@@ -8350,18 +8350,25 @@ name = "serai-ethereum-processor"
 version = "0.1.0"
 dependencies = [
  "borsh",
- "const-hex",
+ "ciphersuite",
- "env_logger",
+ "dkg",
  "ethereum-serai",
+ "flexible-transcript",
  "hex",
  "k256",
  "log",
+ "modular-frost",
  "parity-scale-codec",
+ "rand_core",
+ "serai-client",
  "serai-db",
- "serai-env",
+ "serai-processor-bin",
- "serai-message-queue",
+ "serai-processor-key-gen",
- "serai-processor-messages",
+ "serai-processor-primitives",
- "serde_json",
+ "serai-processor-scanner",
+ "serai-processor-scheduler-primitives",
+ "serai-processor-signers",
+ "serai-processor-smart-contract-scheduler",
  "tokio",
  "zalloc",
 ]
@@ -8781,6 +8788,20 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "serai-processor-smart-contract-scheduler"
+version = "0.1.0"
+dependencies = [
+ "borsh",
+ "group",
+ "parity-scale-codec",
+ "serai-db",
+ "serai-primitives",
+ "serai-processor-primitives",
+ "serai-processor-scanner",
+ "serai-processor-scheduler-primitives",
+]
+
 [[package]]
 name = "serai-processor-tests"
 version = "0.1.0"

Cargo.toml

@@ -81,6 +81,7 @@ members = [
   "processor/scheduler/utxo/primitives",
   "processor/scheduler/utxo/standard",
   "processor/scheduler/utxo/transaction-chaining",
+  "processor/scheduler/smart-contract",
   "processor/signers",
 
   "processor/bin",

deny.toml

@@ -55,6 +55,7 @@ exceptions = [
   { allow = ["AGPL-3.0"], name = "serai-processor-utxo-scheduler-primitives" },
   { allow = ["AGPL-3.0"], name = "serai-processor-standard-scheduler" },
   { allow = ["AGPL-3.0"], name = "serai-processor-transaction-chaining-scheduler" },
+  { allow = ["AGPL-3.0"], name = "serai-processor-smart-contract-scheduler" },
   { allow = ["AGPL-3.0"], name = "serai-processor-signers" },
 
   { allow = ["AGPL-3.0"], name = "serai-bitcoin-processor" },

processor/ethereum/Cargo.toml

@@ -17,27 +17,38 @@ rustdoc-args = ["--cfg", "docsrs"]
 workspace = true
 
 [dependencies]
-const-hex = { version = "1", default-features = false }
+rand_core = { version = "0.6", default-features = false }
+
 hex = { version = "0.4", default-features = false, features = ["std"] }
 scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["std"] }
 borsh = { version = "1", default-features = false, features = ["std", "derive", "de_strict_order"] }
-serde_json = { version = "1", default-features = false, features = ["std"] }
+
+transcript = { package = "flexible-transcript", path = "../../crypto/transcript", default-features = false, features = ["std", "recommended"] }
+ciphersuite = { path = "../../crypto/ciphersuite", default-features = false, features = ["std", "secp256k1"] }
+dkg = { path = "../../crypto/dkg", default-features = false, features = ["std", "evrf-secp256k1"] }
+frost = { package = "modular-frost", path = "../../crypto/frost", default-features = false }
 
 k256 = { version = "^0.13.1", default-features = false, features = ["std"] }
 ethereum-serai = { path = "../../networks/ethereum", default-features = false, optional = true }
 
-log = { version = "0.4", default-features = false, features = ["std"] }
+serai-client = { path = "../../substrate/client", default-features = false, features = ["bitcoin"] }
-env_logger = { version = "0.10", default-features = false, features = ["humantime"] }
-tokio = { version = "1", default-features = false, features = ["rt-multi-thread", "sync", "time", "macros"] }
 
 zalloc = { path = "../../common/zalloc" }
+log = { version = "0.4", default-features = false, features = ["std"] }
+tokio = { version = "1", default-features = false, features = ["rt-multi-thread", "sync", "time", "macros"] }
+
 serai-db = { path = "../../common/db" }
-serai-env = { path = "../../common/env" }
 
-messages = { package = "serai-processor-messages", path = "../messages" }
+key-gen = { package = "serai-processor-key-gen", path = "../key-gen" }
 
-message-queue = { package = "serai-message-queue", path = "../../message-queue" }
+primitives = { package = "serai-processor-primitives", path = "../primitives" }
+scheduler = { package = "serai-processor-scheduler-primitives", path = "../scheduler/primitives" }
+scanner = { package = "serai-processor-scanner", path = "../scanner" }
+smart-contract-scheduler = { package = "serai-processor-smart-contract-scheduler", path = "../scheduler/smart-contract" }
+signers = { package = "serai-processor-signers", path = "../signers" }
+
+bin = { package = "serai-processor-bin", path = "../bin" }
 
 [features]
-parity-db = ["serai-db/parity-db"]
+parity-db = ["bin/parity-db"]
-rocksdb = ["serai-db/rocksdb"]
+rocksdb = ["bin/rocksdb"]

processor/scheduler/smart-contract/Cargo.toml

@@ -0,0 +1,34 @@
+[package]
+name = "serai-processor-smart-contract-scheduler"
+version = "0.1.0"
+description = "Scheduler for a smart contract representing the Serai processor"
+license = "AGPL-3.0-only"
+repository = "https://github.com/serai-dex/serai/tree/develop/processor/scheduler/smart-contract"
+authors = ["Luke Parker <lukeparker5132@gmail.com>"]
+keywords = []
+edition = "2021"
+publish = false
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[package.metadata.cargo-machete]
+ignored = ["scale", "borsh"]
+
+[lints]
+workspace = true
+
+[dependencies]
+group = { version = "0.13", default-features = false }
+
+scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["std"] }
+borsh = { version = "1", default-features = false, features = ["std", "derive", "de_strict_order"] }
+
+serai-primitives = { path = "../../../substrate/primitives", default-features = false, features = ["std"] }
+
+serai-db = { path = "../../../common/db" }
+
+primitives = { package = "serai-processor-primitives", path = "../../primitives" }
+scanner = { package = "serai-processor-scanner", path = "../../scanner" }
+scheduler-primitives = { package = "serai-processor-scheduler-primitives", path = "../primitives" }

processor/scheduler/smart-contract/LICENSE

@@ -0,0 +1,15 @@
+AGPL-3.0-only license
+
+Copyright (c) 2024 Luke Parker
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License Version 3 as
+published by the Free Software Foundation.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.

processor/scheduler/smart-contract/README.md

@@ -0,0 +1,3 @@
+# Smart Contract Scheduler
+
+A scheduler for a smart contract representing the Serai processor.

processor/scheduler/smart-contract/src/lib.rs

@@ -0,0 +1,136 @@
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![doc = include_str!("../README.md")]
+#![deny(missing_docs)]
+
+use core::{marker::PhantomData, future::Future};
+use std::collections::HashMap;
+
+use group::GroupEncoding;
+
+use serai_db::{Get, DbTxn, create_db};
+
+use primitives::{ReceivedOutput, Payment};
+use scanner::{
+  LifetimeStage, ScannerFeed, KeyFor, AddressFor, EventualityFor, BlockFor, SchedulerUpdate,
+  KeyScopedEventualities, Scheduler as SchedulerTrait,
+};
+use scheduler_primitives::*;
+
+create_db! {
+  SmartContractScheduler {
+    NextNonce: () -> u64,
+  }
+}
+
+/// A smart contract.
+pub trait SmartContract<S: ScannerFeed>: 'static + Send {
+  /// The type representing a signable transaction.
+  type SignableTransaction: SignableTransaction;
+
+  /// Rotate from the retiring key to the new key.
+  fn rotate(
+    nonce: u64,
+    retiring_key: KeyFor<S>,
+    new_key: KeyFor<S>,
+  ) -> (Self::SignableTransaction, EventualityFor<S>);
+  /// Fulfill the set of payments, dropping any not worth handling.
+  fn fulfill(
+    starting_nonce: u64,
+    payments: Vec<Payment<AddressFor<S>>>,
+  ) -> Vec<(Self::SignableTransaction, EventualityFor<S>)>;
+}
+
+/// A scheduler for a smart contract representing the Serai processor.
+#[allow(non_snake_case)]
+#[derive(Clone, Default)]
+pub struct Scheduler<S: ScannerFeed, SC: SmartContract<S>> {
+  _S: PhantomData<S>,
+  _SC: PhantomData<SC>,
+}
+
+fn fulfill_payments<S: ScannerFeed, SC: SmartContract<S>>(
+  txn: &mut impl DbTxn,
+  active_keys: &[(KeyFor<S>, LifetimeStage)],
+  payments: Vec<Payment<AddressFor<S>>>,
+) -> KeyScopedEventualities<S> {
+  let key = match active_keys[0].1 {
+    LifetimeStage::ActiveYetNotReporting |
+    LifetimeStage::Active |
+    LifetimeStage::UsingNewForChange => active_keys[0].0,
+    LifetimeStage::Forwarding | LifetimeStage::Finishing => active_keys[1].0,
+  };
+
+  let mut nonce = NextNonce::get(txn).unwrap_or(0);
+  let mut eventualities = Vec::with_capacity(1);
+  for (signable, eventuality) in SC::fulfill(nonce, payments) {
+    TransactionsToSign::<SC::SignableTransaction>::send(txn, &key, &signable);
+    nonce += 1;
+    eventualities.push(eventuality);
+  }
+  NextNonce::set(txn, &nonce);
+  HashMap::from([(key.to_bytes().as_ref().to_vec(), eventualities)])
+}
+
+impl<S: ScannerFeed, SC: SmartContract<S>> SchedulerTrait<S> for Scheduler<S, SC> {
+  type EphemeralError = ();
+  type SignableTransaction = SC::SignableTransaction;
+
+  fn activate_key(_txn: &mut impl DbTxn, _key: KeyFor<S>) {}
+
+  fn flush_key(
+    &self,
+    txn: &mut impl DbTxn,
+    _block: &BlockFor<S>,
+    retiring_key: KeyFor<S>,
+    new_key: KeyFor<S>,
+  ) -> impl Send + Future<Output = Result<KeyScopedEventualities<S>, Self::EphemeralError>> {
+    async move {
+      let nonce = NextNonce::get(txn).unwrap_or(0);
+      let (signable, eventuality) = SC::rotate(nonce, retiring_key, new_key);
+      NextNonce::set(txn, &(nonce + 1));
+      TransactionsToSign::<SC::SignableTransaction>::send(txn, &retiring_key, &signable);
+      Ok(HashMap::from([(retiring_key.to_bytes().as_ref().to_vec(), vec![eventuality])]))
+    }
+  }
+
+  fn retire_key(_txn: &mut impl DbTxn, _key: KeyFor<S>) {}
+
+  fn update(
+    &self,
+    txn: &mut impl DbTxn,
+    _block: &BlockFor<S>,
+    active_keys: &[(KeyFor<S>, LifetimeStage)],
+    update: SchedulerUpdate<S>,
+  ) -> impl Send + Future<Output = Result<KeyScopedEventualities<S>, Self::EphemeralError>> {
+    async move {
+      // We ignore the outputs as we don't need to know our current state as it never suffers
+      // partial availability
+
+      // We shouldn't have any forwards though
+      assert!(update.forwards().is_empty());
+
+      // Create the transactions for the returns
+      Ok(fulfill_payments::<S, SC>(
+        txn,
+        active_keys,
+        update
+          .returns()
+          .iter()
+          .map(|to_return| {
+            Payment::new(to_return.address().clone(), to_return.output().balance(), None)
+          })
+          .collect::<Vec<_>>(),
+      ))
+    }
+  }
+
+  fn fulfill(
+    &self,
+    txn: &mut impl DbTxn,
+    _block: &BlockFor<S>,
+    active_keys: &[(KeyFor<S>, LifetimeStage)],
+    payments: Vec<Payment<AddressFor<S>>>,
+  ) -> impl Send + Future<Output = Result<KeyScopedEventualities<S>, Self::EphemeralError>> {
+    async move { Ok(fulfill_payments::<S, SC>(txn, active_keys, payments)) }
+  }
+}

processor/scheduler/utxo/standard/src/lib.rs

@@ -470,7 +470,7 @@ impl<S: ScannerFeed, P: TransactionPlanner<S, ()>> SchedulerTrait<S> for Schedul
         }
       }
 
-      // Create the transactions for the forwards/burns
+      // Create the transactions for the forwards/returns
       {
         let mut planned_txs = vec![];
         for forward in update.forwards() {

processor/scheduler/utxo/transaction-chaining/src/lib.rs

@@ -488,7 +488,7 @@ impl<S: ScannerFeed, P: TransactionPlanner<S, EffectedReceivedOutputs<S>>> Sched
         }
       }
 
-      // Create the transactions for the forwards/burns
+      // Create the transactions for the forwards/returns
       {
         let mut planned_txs = vec![];
         for forward in update.forwards() {

processor/src/multisigs/scheduler/smart_contract.rs

@@ -1,208 +0,0 @@
-use std::{io, collections::HashSet};
-
-use ciphersuite::{group::GroupEncoding, Ciphersuite};
-
-use serai_client::primitives::{NetworkId, Coin, Balance};
-
-use crate::{
-  Get, DbTxn, Db, Payment, Plan, create_db,
-  networks::{Output, Network},
-  multisigs::scheduler::{SchedulerAddendum, Scheduler as SchedulerTrait},
-};
-
-#[derive(Clone, PartialEq, Eq, Debug)]
-pub struct Scheduler<N: Network> {
-  key: <N::Curve as Ciphersuite>::G,
-  coins: HashSet<Coin>,
-  rotated: bool,
-}
-
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub enum Addendum<N: Network> {
-  Nonce(u64),
-  RotateTo { nonce: u64, new_key: <N::Curve as Ciphersuite>::G },
-}
-
-impl<N: Network> SchedulerAddendum for Addendum<N> {
-  fn read<R: io::Read>(reader: &mut R) -> io::Result<Self> {
-    let mut kind = [0xff];
-    reader.read_exact(&mut kind)?;
-    match kind[0] {
-      0 => {
-        let mut nonce = [0; 8];
-        reader.read_exact(&mut nonce)?;
-        Ok(Addendum::Nonce(u64::from_le_bytes(nonce)))
-      }
-      1 => {
-        let mut nonce = [0; 8];
-        reader.read_exact(&mut nonce)?;
-        let nonce = u64::from_le_bytes(nonce);
-
-        let new_key = N::Curve::read_G(reader)?;
-        Ok(Addendum::RotateTo { nonce, new_key })
-      }
-      _ => Err(io::Error::other("reading unknown Addendum type"))?,
-    }
-  }
-  fn write<W: io::Write>(&self, writer: &mut W) -> io::Result<()> {
-    match self {
-      Addendum::Nonce(nonce) => {
-        writer.write_all(&[0])?;
-        writer.write_all(&nonce.to_le_bytes())
-      }
-      Addendum::RotateTo { nonce, new_key } => {
-        writer.write_all(&[1])?;
-        writer.write_all(&nonce.to_le_bytes())?;
-        writer.write_all(new_key.to_bytes().as_ref())
-      }
-    }
-  }
-}
-
-create_db! {
-  SchedulerDb {
-    LastNonce: () -> u64,
-    RotatedTo: (key: &[u8]) -> Vec<u8>,
-  }
-}
-
-impl<N: Network<Scheduler = Self>> SchedulerTrait<N> for Scheduler<N> {
-  type Addendum = Addendum<N>;
-
-  /// Check if this Scheduler is empty.
-  fn empty(&self) -> bool {
-    self.rotated
-  }
-
-  /// Create a new Scheduler.
-  fn new<D: Db>(
-    _txn: &mut D::Transaction<'_>,
-    key: <N::Curve as Ciphersuite>::G,
-    network: NetworkId,
-  ) -> Self {
-    assert!(N::branch_address(key).is_none());
-    assert!(N::change_address(key).is_none());
-    assert!(N::forward_address(key).is_none());
-
-    Scheduler { key, coins: network.coins().iter().copied().collect(), rotated: false }
-  }
-
-  /// Load a Scheduler from the DB.
-  fn from_db<D: Db>(
-    db: &D,
-    key: <N::Curve as Ciphersuite>::G,
-    network: NetworkId,
-  ) -> io::Result<Self> {
-    Ok(Scheduler {
-      key,
-      coins: network.coins().iter().copied().collect(),
-      rotated: RotatedTo::get(db, key.to_bytes().as_ref()).is_some(),
-    })
-  }
-
-  fn can_use_branch(&self, _balance: Balance) -> bool {
-    false
-  }
-
-  fn schedule<D: Db>(
-    &mut self,
-    txn: &mut D::Transaction<'_>,
-    utxos: Vec<N::Output>,
-    payments: Vec<Payment<N>>,
-    key_for_any_change: <N::Curve as Ciphersuite>::G,
-    force_spend: bool,
-  ) -> Vec<Plan<N>> {
-    for utxo in utxos {
-      assert!(self.coins.contains(&utxo.balance().coin));
-    }
-
-    let mut nonce = LastNonce::get(txn).unwrap_or(1);
-    let mut plans = vec![];
-    for chunk in payments.as_slice().chunks(N::MAX_OUTPUTS) {
-      // Once we rotate, all further payments should be scheduled via the new multisig
-      assert!(!self.rotated);
-      plans.push(Plan {
-        key: self.key,
-        inputs: vec![],
-        payments: chunk.to_vec(),
-        change: None,
-        scheduler_addendum: Addendum::Nonce(nonce),
-      });
-      nonce += 1;
-    }
-
-    // If we're supposed to rotate to the new key, create an empty Plan which will signify the key
-    // update
-    if force_spend && (!self.rotated) {
-      plans.push(Plan {
-        key: self.key,
-        inputs: vec![],
-        payments: vec![],
-        change: None,
-        scheduler_addendum: Addendum::RotateTo { nonce, new_key: key_for_any_change },
-      });
-      nonce += 1;
-      self.rotated = true;
-      RotatedTo::set(
-        txn,
-        self.key.to_bytes().as_ref(),
-        &key_for_any_change.to_bytes().as_ref().to_vec(),
-      );
-    }
-
-    LastNonce::set(txn, &nonce);
-
-    plans
-  }
-
-  fn consume_payments<D: Db>(&mut self, _txn: &mut D::Transaction<'_>) -> Vec<Payment<N>> {
-    vec![]
-  }
-
-  fn created_output<D: Db>(
-    &mut self,
-    _txn: &mut D::Transaction<'_>,
-    _expected: u64,
-    _actual: Option<u64>,
-  ) {
-    panic!("Smart Contract Scheduler created a Branch output")
-  }
-
-  /// Refund a specific output.
-  fn refund_plan<D: Db>(
-    &mut self,
-    txn: &mut D::Transaction<'_>,
-    output: N::Output,
-    refund_to: N::Address,
-  ) -> Plan<N> {
-    let current_key = RotatedTo::get(txn, self.key.to_bytes().as_ref())
-      .and_then(|key_bytes| <N::Curve as Ciphersuite>::read_G(&mut key_bytes.as_slice()).ok())
-      .unwrap_or(self.key);
-
-    let nonce = LastNonce::get(txn).map_or(1, |nonce| nonce + 1);
-    LastNonce::set(txn, &(nonce + 1));
-    Plan {
-      key: current_key,
-      inputs: vec![],
-      payments: vec![Payment { address: refund_to, data: None, balance: output.balance() }],
-      change: None,
-      scheduler_addendum: Addendum::Nonce(nonce),
-    }
-  }
-
-  fn shim_forward_plan(_output: N::Output, _to: <N::Curve as Ciphersuite>::G) -> Option<Plan<N>> {
-    None
-  }
-
-  /// Forward a specific output to the new multisig.
-  ///
-  /// Returns None if no forwarding is necessary.
-  fn forward_plan<D: Db>(
-    &mut self,
-    _txn: &mut D::Transaction<'_>,
-    _output: N::Output,
-    _to: <N::Curve as Ciphersuite>::G,
-  ) -> Option<Plan<N>> {
-    None
-  }
-}