Replace custom read/write impls in router with borsh

Cargo.lock

@@ -9455,6 +9455,7 @@ version = "0.1.0"
 dependencies = [
  "alloy-consensus",
  "alloy-primitives",
+ "borsh",
  "group",
  "k256",
 ]
@@ -9475,6 +9476,7 @@ dependencies = [
  "alloy-sol-macro-input",
  "alloy-sol-types",
  "alloy-transport",
+ "borsh",
  "build-solidity-contracts",
  "ethereum-schnorr-contract",
  "group",

processor/ethereum/primitives/Cargo.toml

@@ -17,6 +17,8 @@ rustdoc-args = ["--cfg", "docsrs"]
 workspace = true
 
 [dependencies]
+borsh = { version = "1", default-features = false, features = ["std", "derive", "de_strict_order"] }
+
 group = { version = "0.13", default-features = false }
 k256 = { version = "^0.13.1", default-features = false, features = ["std", "arithmetic"] }
 

processor/ethereum/primitives/src/borsh.rs

@@ -0,0 +1,24 @@
+use ::borsh::{io, BorshSerialize, BorshDeserialize};
+
+use alloy_primitives::{U256, Address};
+
+/// Serialize a U256 with a borsh-compatible API.
+pub fn serialize_u256(value: &U256, writer: &mut impl io::Write) -> io::Result<()> {
+  let value: [u8; 32] = value.to_be_bytes();
+  value.serialize(writer)
+}
+
+/// Deserialize an address with a borsh-compatible API.
+pub fn deserialize_u256(reader: &mut impl io::Read) -> io::Result<U256> {
+  <[u8; 32]>::deserialize_reader(reader).map(|value| U256::from_be_bytes(value))
+}
+
+/// Serialize an address with a borsh-compatible API.
+pub fn serialize_address(address: &Address, writer: &mut impl io::Write) -> io::Result<()> {
+  <[u8; 20]>::from(address.0).serialize(writer)
+}
+
+/// Deserialize an address with a borsh-compatible API.
+pub fn deserialize_address(reader: &mut impl io::Read) -> io::Result<Address> {
+  <[u8; 20]>::deserialize_reader(reader).map(|address| Address(address.into()))
+}

processor/ethereum/primitives/src/lib.rs

@@ -2,12 +2,27 @@
 #![doc = include_str!("../README.md")]
 #![deny(missing_docs)]
 
+use ::borsh::{BorshSerialize, BorshDeserialize};
+
 use group::ff::PrimeField;
 use k256::Scalar;
 
 use alloy_primitives::PrimitiveSignature;
 use alloy_consensus::{SignableTransaction, Signed, TxLegacy};
 
+mod borsh;
+pub use borsh::*;
+
+/// An index of a log within a block.
+#[derive(Clone, Copy, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
+#[borsh(crate = "::borsh")]
+pub struct LogIndex {
+  /// The hash of the block which produced this log.
+  pub block_hash: [u8; 32],
+  /// The index of this log within the execution of the block.
+  pub index_within_block: u64,
+}
+
 /// The Keccak256 hash function.
 pub fn keccak256(data: impl AsRef<[u8]>) -> [u8; 32] {
   alloy_primitives::keccak256(data.as_ref()).into()

processor/ethereum/router/Cargo.toml

@@ -17,6 +17,8 @@ rustdoc-args = ["--cfg", "docsrs"]
 workspace = true
 
 [dependencies]
+borsh = { version = "1", default-features = false, features = ["std", "derive", "de_strict_order"] }
+
 group = { version = "0.13", default-features = false }
 
 alloy-core = { version = "0.8", default-features = false }

processor/ethereum/router/src/lib.rs

@@ -2,7 +2,9 @@
 #![doc = include_str!("../README.md")]
 #![deny(missing_docs)]
 
-use std::{sync::Arc, io, collections::HashSet};
+use std::{sync::Arc, collections::HashSet};
+
+use borsh::{BorshSerialize, BorshDeserialize};
 
 use group::ff::PrimeField;
 
@@ -16,6 +18,7 @@ use alloy_transport::{TransportErrorKind, RpcError};
 use alloy_simple_request_transport::SimpleRequest;
 use alloy_provider::{Provider, RootProvider};
 
+use ethereum_primitives::LogIndex;
 use ethereum_schnorr::{PublicKey, Signature};
 use ethereum_deployer::Deployer;
 use erc20::{Transfer, Erc20};
@@ -65,12 +68,18 @@ impl From<&Signature> for abi::Signature {
 }
 
 /// A coin on Ethereum.
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
 pub enum Coin {
   /// Ether, the native coin of Ethereum.
   Ether,
   /// An ERC20 token.
-  Erc20(Address),
+  Erc20(
+    #[borsh(
+      serialize_with = "ethereum_primitives::serialize_address",
+      deserialize_with = "ethereum_primitives::deserialize_address"
+    )]
+    Address,
+  ),
 }
 
 impl Coin {
@@ -80,100 +89,31 @@ impl Coin {
       Coin::Erc20(address) => *address,
     }
   }
-
-  /// Read a `Coin`.
-  pub fn read<R: io::Read>(reader: &mut R) -> io::Result<Self> {
-    let mut kind = [0xff];
-    reader.read_exact(&mut kind)?;
-    Ok(match kind[0] {
-      0 => Coin::Ether,
-      1 => {
-        let mut address = [0; 20];
-        reader.read_exact(&mut address)?;
-        Coin::Erc20(address.into())
-      }
-      _ => Err(io::Error::other("unrecognized Coin type"))?,
-    })
-  }
-
-  /// Write the `Coin`.
-  pub fn write<W: io::Write>(&self, writer: &mut W) -> io::Result<()> {
-    match self {
-      Coin::Ether => writer.write_all(&[0]),
-      Coin::Erc20(token) => {
-        writer.write_all(&[1])?;
-        writer.write_all(token.as_ref())
-      }
-    }
-  }
 }
 
 /// An InInstruction from the Router.
-#[derive(Clone, PartialEq, Eq, Debug)]
+#[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
 pub struct InInstruction {
   /// The ID for this `InInstruction`.
-  pub id: ([u8; 32], u64),
+  pub id: LogIndex,
   /// The address which transferred these coins to Serai.
-  pub from: [u8; 20],
+  #[borsh(
+    serialize_with = "ethereum_primitives::serialize_address",
+    deserialize_with = "ethereum_primitives::deserialize_address"
+  )]
+  pub from: Address,
   /// The coin transferred.
   pub coin: Coin,
   /// The amount transferred.
+  #[borsh(
+    serialize_with = "ethereum_primitives::serialize_u256",
+    deserialize_with = "ethereum_primitives::deserialize_u256"
+  )]
   pub amount: U256,
   /// The data associated with the transfer.
   pub data: Vec<u8>,
 }
 
-impl InInstruction {
-  /// Read an `InInstruction`.
-  pub fn read<R: io::Read>(reader: &mut R) -> io::Result<Self> {
-    let id = {
-      let mut id_hash = [0; 32];
-      reader.read_exact(&mut id_hash)?;
-      let mut id_pos = [0; 8];
-      reader.read_exact(&mut id_pos)?;
-      let id_pos = u64::from_le_bytes(id_pos);
-      (id_hash, id_pos)
-    };
-
-    let mut from = [0; 20];
-    reader.read_exact(&mut from)?;
-
-    let coin = Coin::read(reader)?;
-    let mut amount = [0; 32];
-    reader.read_exact(&mut amount)?;
-    let amount = U256::from_le_slice(&amount);
-
-    let mut data_len = [0; 4];
-    reader.read_exact(&mut data_len)?;
-    let data_len = usize::try_from(u32::from_le_bytes(data_len))
-      .map_err(|_| io::Error::other("InInstruction data exceeded 2**32 in length"))?;
-    let mut data = vec![0; data_len];
-    reader.read_exact(&mut data)?;
-
-    Ok(InInstruction { id, from, coin, amount, data })
-  }
-
-  /// Write the `InInstruction`.
-  pub fn write<W: io::Write>(&self, writer: &mut W) -> io::Result<()> {
-    writer.write_all(&self.id.0)?;
-    writer.write_all(&self.id.1.to_le_bytes())?;
-
-    writer.write_all(&self.from)?;
-
-    self.coin.write(writer)?;
-    writer.write_all(&self.amount.as_le_bytes())?;
-
-    writer.write_all(
-      &u32::try_from(self.data.len())
-        .map_err(|_| {
-          io::Error::other("InInstruction being written had data exceeding 2**32 in length")
-        })?
-        .to_le_bytes(),
-    )?;
-    writer.write_all(&self.data)
-  }
-}
-
 /// A list of `OutInstruction`s.
 #[derive(Clone)]
 pub struct OutInstructions(Vec<abi::OutInstruction>);
@@ -205,7 +145,7 @@ impl From<&[(SeraiAddress, U256)]> for OutInstructions {
 }
 
 /// An action which was executed by the Router.
-#[derive(Clone, PartialEq, Eq, Debug)]
+#[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
 pub enum Executed {
   /// New key was set.
   SetKey {
@@ -230,44 +170,6 @@ impl Executed {
       Executed::SetKey { nonce, .. } | Executed::Batch { nonce, .. } => *nonce,
     }
   }
-
-  /// Write the Executed.
-  pub fn write(&self, writer: &mut impl io::Write) -> io::Result<()> {
-    match self {
-      Self::SetKey { nonce, key } => {
-        writer.write_all(&[0])?;
-        writer.write_all(&nonce.to_le_bytes())?;
-        writer.write_all(key)
-      }
-      Self::Batch { nonce, message_hash } => {
-        writer.write_all(&[1])?;
-        writer.write_all(&nonce.to_le_bytes())?;
-        writer.write_all(message_hash)
-      }
-    }
-  }
-
-  /// Read an Executed.
-  pub fn read(reader: &mut impl io::Read) -> io::Result<Self> {
-    let mut kind = [0xff];
-    reader.read_exact(&mut kind)?;
-    if kind[0] >= 2 {
-      Err(io::Error::other("unrecognized type of Executed"))?;
-    }
-
-    let mut nonce = [0; 8];
-    reader.read_exact(&mut nonce)?;
-    let nonce = u64::from_le_bytes(nonce);
-
-    let mut payload = [0; 32];
-    reader.read_exact(&mut payload)?;
-
-    Ok(match kind[0] {
-      0 => Self::SetKey { nonce, key: payload },
-      1 => Self::Batch { nonce, message_hash: payload },
-      _ => unreachable!(),
-    })
-  }
 }
 
 /// A view of the Router for Serai.
@@ -452,17 +354,17 @@ impl Router {
         ))?;
       }
 
-      let id = (
-        log
+      let id = LogIndex {
+        block_hash: log
           .block_hash
           .ok_or_else(|| {
             TransportErrorKind::Custom("log didn't have its block hash set".to_string().into())
           })?
           .into(),
-        log.log_index.ok_or_else(|| {
+        index_within_block: log.log_index.ok_or_else(|| {
           TransportErrorKind::Custom("log didn't have its index set".to_string().into())
         })?,
-      );
+      };
 
       let tx_hash = log.transaction_hash.ok_or_else(|| {
         TransportErrorKind::Custom("log didn't have its transaction hash set".to_string().into())
@@ -551,7 +453,7 @@ impl Router {
 
       in_instructions.push(InInstruction {
         id,
-        from: *log.from.0,
+        from: log.from,
         coin,
         amount: log.amount,
         data: log.instruction.as_ref().to_vec(),

processor/ethereum/router/src/tests/mod.rs

@@ -17,13 +17,12 @@ use alloy_provider::RootProvider;
 
 use alloy_node_bindings::{Anvil, AnvilInstance};
 
+use ethereum_primitives::LogIndex;
 use ethereum_schnorr::{PublicKey, Signature};
 use ethereum_deployer::Deployer;
 
 use crate::{Coin, OutInstructions, Router};
 
-mod read_write;
-
 #[test]
 fn execute_reentrancy_guard() {
   let hash = alloy_core::primitives::keccak256(b"ReentrancyGuard Router.execute");
@@ -217,7 +216,10 @@ async fn test_eth_in_instruction() {
   assert_eq!(parsed_in_instructions.len(), 1);
   assert_eq!(
     parsed_in_instructions[0].id,
-    (<[u8; 32]>::from(receipt.block_hash.unwrap()), receipt.inner.logs()[0].log_index.unwrap())
+    LogIndex {
+      block_hash: *receipt.block_hash.unwrap(),
+      index_within_block: receipt.inner.logs()[0].log_index.unwrap(),
+    },
   );
   assert_eq!(parsed_in_instructions[0].from, signer);
   assert_eq!(parsed_in_instructions[0].coin, Coin::Ether);

processor/ethereum/router/src/tests/read_write.rs

@@ -1,85 +0,0 @@
-use rand_core::{RngCore, OsRng};
-
-use alloy_core::primitives::U256;
-
-use crate::{Coin, InInstruction, Executed};
-
-fn coins() -> [Coin; 2] {
-  [Coin::Ether, {
-    let mut erc20 = [0; 20];
-    OsRng.fill_bytes(&mut erc20);
-    Coin::Erc20(erc20.into())
-  }]
-}
-
-#[test]
-fn test_coin_read_write() {
-  for coin in coins() {
-    let mut res = vec![];
-    coin.write(&mut res).unwrap();
-    assert_eq!(coin, Coin::read(&mut res.as_slice()).unwrap());
-  }
-}
-
-#[test]
-fn test_in_instruction_read_write() {
-  for coin in coins() {
-    let instruction = InInstruction {
-      id: (
-        {
-          let mut tx_id = [0; 32];
-          OsRng.fill_bytes(&mut tx_id);
-          tx_id
-        },
-        OsRng.next_u64(),
-      ),
-      from: {
-        let mut from = [0; 20];
-        OsRng.fill_bytes(&mut from);
-        from
-      },
-      coin,
-      amount: U256::from_le_bytes({
-        let mut amount = [0; 32];
-        OsRng.fill_bytes(&mut amount);
-        amount
-      }),
-      data: {
-        let len = usize::try_from(OsRng.next_u64() % 65536).unwrap();
-        let mut data = vec![0; len];
-        OsRng.fill_bytes(&mut data);
-        data
-      },
-    };
-
-    let mut buf = vec![];
-    instruction.write(&mut buf).unwrap();
-    assert_eq!(InInstruction::read(&mut buf.as_slice()).unwrap(), instruction);
-  }
-}
-
-#[test]
-fn test_executed_read_write() {
-  for executed in [
-    Executed::SetKey {
-      nonce: OsRng.next_u64(),
-      key: {
-        let mut key = [0; 32];
-        OsRng.fill_bytes(&mut key);
-        key
-      },
-    },
-    Executed::Batch {
-      nonce: OsRng.next_u64(),
-      message_hash: {
-        let mut message_hash = [0; 32];
-        OsRng.fill_bytes(&mut message_hash);
-        message_hash
-      },
-    },
-  ] {
-    let mut res = vec![];
-    executed.write(&mut res).unwrap();
-    assert_eq!(executed, Executed::read(&mut res.as_slice()).unwrap());
-  }
-}

processor/ethereum/src/primitives/output.rs

@@ -145,7 +145,7 @@ impl ReceivedOutput<<Secp256k1 as Ciphersuite>::G, Address> for Output {
       Output::Output { key, instruction } => {
         writer.write_all(&[0])?;
         writer.write_all(key.to_bytes().as_ref())?;
-        instruction.write(writer)
+        instruction.serialize(writer)
       }
       Output::Eventuality { key, nonce } => {
         writer.write_all(&[1])?;
@@ -164,7 +164,7 @@ impl ReceivedOutput<<Secp256k1 as Ciphersuite>::G, Address> for Output {
     Ok(match kind[0] {
       0 => {
         let key = Secp256k1::read_G(reader)?;
-        let instruction = EthereumInInstruction::read(reader)?;
+        let instruction = EthereumInInstruction::deserialize_reader(reader)?;
         Self::Output { key, instruction }
       }
       1 => {