diff --git a/Cargo.lock b/Cargo.lock index 4761c859f8839..49d06d9a67eef 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -3845,6 +3845,21 @@ dependencies = [ "sp-std", ] +[[package]] +name = "pallet-atomic-swap" +version = "2.0.0-rc3" +dependencies = [ + "frame-support", + "frame-system", + "pallet-balances", + "parity-scale-codec", + "serde", + "sp-core", + "sp-io", + "sp-runtime", + "sp-std", +] + [[package]] name = "pallet-aura" version = "2.0.0-rc3" diff --git a/Cargo.toml b/Cargo.toml index d3004fcadca5a..d1c7339b993fd 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -60,6 +60,7 @@ members = [ "utils/wasm-builder-runner", "frame/assets", "frame/aura", + "frame/atomic-swap", "frame/authority-discovery", "frame/authorship", "frame/babe", diff --git a/bin/node/runtime/src/lib.rs b/bin/node/runtime/src/lib.rs index d776d72e2b4cf..d5773d7941c6e 100644 --- a/bin/node/runtime/src/lib.rs +++ b/bin/node/runtime/src/lib.rs @@ -96,8 +96,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion { // and set impl_version to 0. If only runtime // implementation changes and behavior does not, then leave spec_version as // is and increment impl_version. - spec_version: 252, - impl_version: 1, + spec_version: 253, + impl_version: 0, apis: RUNTIME_API_VERSIONS, transaction_version: 1, }; diff --git a/frame/atomic-swap/Cargo.toml b/frame/atomic-swap/Cargo.toml new file mode 100644 index 0000000000000..be197096e7727 --- /dev/null +++ b/frame/atomic-swap/Cargo.toml @@ -0,0 +1,39 @@ +[package] +name = "pallet-atomic-swap" +version = "2.0.0-rc3" +authors = ["Parity Technologies "] +edition = "2018" +license = "Apache-2.0" +homepage = "https://substrate.dev" +repository = "https://github.com/paritytech/substrate/" +description = "FRAME atomic swap pallet" + +[package.metadata.docs.rs] +targets = ["x86_64-unknown-linux-gnu"] + +[dependencies] +serde = { version = "1.0.101", optional = true } +codec = { package = "parity-scale-codec", version = "1.3.0", default-features = false } +frame-support = { version = "2.0.0-rc3", default-features = false, path = "../support" } +frame-system = { version = "2.0.0-rc3", default-features = false, path = "../system" } +sp-runtime = { version = "2.0.0-rc3", default-features = false, path = "../../primitives/runtime" } +sp-std = { version = "2.0.0-rc3", default-features = false, path = "../../primitives/std" } +sp-io = { version = "2.0.0-rc3", default-features = false, path = "../../primitives/io" } +sp-core = { version = "2.0.0-rc3", default-features = false, path = "../../primitives/core" } + +[dev-dependencies] +pallet-balances = { version = "2.0.0-rc3", default-features = false, path = "../balances" } + +[features] +default = ["std"] +std = [ + "serde", + "codec/std", + "frame-support/std", + "frame-system/std", + "sp-runtime/std", + "sp-std/std", + "sp-io/std", + "sp-core/std", + "pallet-balances/std", +] diff --git a/frame/atomic-swap/src/lib.rs b/frame/atomic-swap/src/lib.rs new file mode 100644 index 0000000000000..aa33c9a849fff --- /dev/null +++ b/frame/atomic-swap/src/lib.rs @@ -0,0 +1,248 @@ +// This file is part of Substrate. + +// Copyright (C) 2017-2020 Parity Technologies (UK) Ltd. +// SPDX-License-Identifier: Apache-2.0 + +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +//! # Atomic swap support pallet + +// Ensure we're `no_std` when compiling for Wasm. +#![cfg_attr(not(feature = "std"), no_std)] + +mod tests; + +use sp_std::prelude::*; +use sp_io::hashing::blake2_256; +use frame_support::{ + decl_module, decl_storage, decl_event, decl_error, ensure, + traits::{Get, Currency, ReservableCurrency, BalanceStatus}, + weights::Weight, + dispatch::DispatchResult, +}; +use frame_system::{self as system, ensure_signed}; +use codec::{Encode, Decode}; +use sp_runtime::RuntimeDebug; + +/// Pending atomic swap operation. +#[derive(Clone, RuntimeDebug, Eq, PartialEq, Encode, Decode)] +pub struct PendingSwap { + /// Source of the swap. + pub source: AccountId, + /// Balance value of the swap. + pub balance: Balance, + /// End block of the lock. + pub end_block: BlockNumber, +} + +/// Balance type from the pallet's point of view. +pub type BalanceFor = <::Currency as Currency<::AccountId>>::Balance; + +/// AccountId type from the pallet's point of view. +pub type AccountIdFor = ::AccountId; + +/// BlockNumber type from the pallet's point of view. +pub type BlockNumberFor = ::BlockNumber; + +/// PendingSwap type from the pallet's point of view. +pub type PendingSwapFor = PendingSwap, BalanceFor, BlockNumberFor>; + +/// Hashed proof type. +pub type HashedProof = [u8; 32]; + +/// Atomic swap's pallet configuration trait. +pub trait Trait: frame_system::Trait { + /// The overarching event type. + type Event: From> + Into<::Event>; + /// The currency mechanism. + type Currency: ReservableCurrency; + /// Limit of proof size. + /// + /// Atomic swap is only atomic if once the proof is revealed, both parties can submit the proofs + /// on-chain. If A is the one that generates the proof, then it requires that either: + /// - A's blockchain has the same proof length limit as B's blockchain. + /// - Or A's blockchain has shorter proof length limit as B's blockchain. + /// + /// If B sees A is on a blockchain with larger proof length limit, then it should kindly refuse + /// to accept the atomic swap request if A generates the proof, and asks that B generates the + /// proof instead. + type ProofLimit: Get; +} + +decl_storage! { + trait Store for Module as AtomicSwap { + pub PendingSwaps: double_map + hasher(twox_64_concat) T::AccountId, hasher(blake2_128_concat) HashedProof + => Option>; + } +} + +decl_error! { + pub enum Error for Module { + /// Swap already exists. + AlreadyExist, + /// Swap proof is invalid. + InvalidProof, + /// Proof is too large. + ProofTooLarge, + /// Source does not match. + SourceMismatch, + /// Swap has already been claimed. + AlreadyClaimed, + /// Swap does not exist. + NotExist, + /// Duration has not yet passed for the swap to be cancelled. + DurationNotPassed, + } +} + +decl_event!( + /// Event of atomic swap pallet. + pub enum Event where + Balance = BalanceFor, + AccountId = AccountIdFor, + PendingSwap = PendingSwapFor, + { + /// Swap created. + NewSwap(AccountId, HashedProof, PendingSwap), + /// Swap claimed. The last parameter indicates whether the execution succeeds. + SwapClaimed(AccountId, HashedProof, Balance, bool), + /// Swap cancelled. + SwapCancelled(AccountId, HashedProof), + } +); + +decl_module! { + /// Module definition of atomic swap pallet. + pub struct Module for enum Call where origin: T::Origin { + type Error = Error; + + fn deposit_event() = default; + + /// Register a new atomic swap, declaring an intention to send funds from origin to target + /// on the current blockchain. The target can claim the fund using the revealed proof. If + /// the fund is not claimed after `duration` blocks, then the sender can cancel the swap. + /// + /// The dispatch origin for this call must be _Signed_. + /// + /// - `target`: Receiver of the atomic swap. + /// - `hashed_proof`: The blake2_256 hash of the secret proof. + /// - `balance`: Funds to be sent from origin. + /// - `duration`: Locked duration of the atomic swap. For safety reasons, it is recommended + /// that the revealer uses a shorter duration than the counterparty, to prevent the + /// situation where the revealer reveals the proof too late around the end block. + #[weight = T::DbWeight::get().reads_writes(1, 1).saturating_add(40_000_000)] + fn create_swap( + origin, + target: AccountIdFor, + hashed_proof: HashedProof, + balance: BalanceFor, + duration: BlockNumberFor, + ) { + let source = ensure_signed(origin)?; + ensure!( + !PendingSwaps::::contains_key(&target, hashed_proof), + Error::::AlreadyExist + ); + + T::Currency::reserve(&source, balance)?; + + let swap = PendingSwap { + source, + balance, + end_block: frame_system::Module::::block_number() + duration, + }; + PendingSwaps::::insert(target.clone(), hashed_proof.clone(), swap.clone()); + + Self::deposit_event( + RawEvent::NewSwap(target, hashed_proof, swap) + ); + } + + /// Claim an atomic swap. + /// + /// The dispatch origin for this call must be _Signed_. + /// + /// - `proof`: Revealed proof of the claim. + #[weight = T::DbWeight::get().reads_writes(2, 2) + .saturating_add(40_000_000) + .saturating_add((proof.len() as Weight).saturating_mul(100)) + ] + fn claim_swap( + origin, + proof: Vec, + ) -> DispatchResult { + ensure!( + proof.len() <= T::ProofLimit::get() as usize, + Error::::ProofTooLarge, + ); + + let target = ensure_signed(origin)?; + let hashed_proof = blake2_256(&proof); + + let swap = PendingSwaps::::get(&target, hashed_proof) + .ok_or(Error::::InvalidProof)?; + + let succeeded = T::Currency::repatriate_reserved( + &swap.source, + &target, + swap.balance, + BalanceStatus::Free, + ).is_ok(); + + PendingSwaps::::remove(target.clone(), hashed_proof.clone()); + + Self::deposit_event( + RawEvent::SwapClaimed(target, hashed_proof, swap.balance, succeeded) + ); + + Ok(()) + } + + /// Cancel an atomic swap. Only possible after the originally set duration has passed. + /// + /// The dispatch origin for this call must be _Signed_. + /// + /// - `target`: Target of the original atomic swap. + /// - `hashed_proof`: Hashed proof of the original atomic swap. + #[weight = T::DbWeight::get().reads_writes(1, 1).saturating_add(40_000_000)] + fn cancel_swap( + origin, + target: AccountIdFor, + hashed_proof: HashedProof, + ) { + let source = ensure_signed(origin)?; + + let swap = PendingSwaps::::get(&target, hashed_proof) + .ok_or(Error::::NotExist)?; + ensure!( + swap.source == source, + Error::::SourceMismatch, + ); + ensure!( + frame_system::Module::::block_number() >= swap.end_block, + Error::::DurationNotPassed, + ); + + T::Currency::unreserve( + &swap.source, + swap.balance, + ); + PendingSwaps::::remove(&target, hashed_proof.clone()); + + Self::deposit_event( + RawEvent::SwapCancelled(target, hashed_proof) + ); + } + } +} diff --git a/frame/atomic-swap/src/tests.rs b/frame/atomic-swap/src/tests.rs new file mode 100644 index 0000000000000..72db841de19df --- /dev/null +++ b/frame/atomic-swap/src/tests.rs @@ -0,0 +1,155 @@ +#![cfg(test)] + +use super::*; + +use frame_support::{ + impl_outer_origin, parameter_types, weights::Weight, +}; +use sp_core::H256; +// The testing primitives are very useful for avoiding having to work with signatures +// or public keys. `u64` is used as the `AccountId` and no `Signature`s are required. +use sp_runtime::{ + Perbill, + testing::Header, + traits::{BlakeTwo256, IdentityLookup}, +}; + +impl_outer_origin! { + pub enum Origin for Test where system = frame_system {} +} + +// For testing the pallet, we construct most of a mock runtime. This means +// first constructing a configuration type (`Test`) which `impl`s each of the +// configuration traits of pallets we want to use. +#[derive(Clone, Eq, PartialEq)] +pub struct Test; +parameter_types! { + pub const BlockHashCount: u64 = 250; + pub const MaximumBlockWeight: Weight = 1024; + pub const MaximumBlockLength: u32 = 2 * 1024; + pub const AvailableBlockRatio: Perbill = Perbill::one(); +} +impl frame_system::Trait for Test { + type BaseCallFilter = (); + type Origin = Origin; + type Index = u64; + type BlockNumber = u64; + type Hash = H256; + type Call = (); + type Hashing = BlakeTwo256; + type AccountId = u64; + type Lookup = IdentityLookup; + type Header = Header; + type Event = (); + type BlockHashCount = BlockHashCount; + type MaximumBlockWeight = MaximumBlockWeight; + type DbWeight = (); + type BlockExecutionWeight = (); + type ExtrinsicBaseWeight = (); + type MaximumExtrinsicWeight = MaximumBlockWeight; + type MaximumBlockLength = MaximumBlockLength; + type AvailableBlockRatio = AvailableBlockRatio; + type Version = (); + type ModuleToIndex = (); + type AccountData = pallet_balances::AccountData; + type OnNewAccount = (); + type OnKilledAccount = (); +} +parameter_types! { + pub const ExistentialDeposit: u64 = 1; +} +impl pallet_balances::Trait for Test { + type Balance = u64; + type DustRemoval = (); + type Event = (); + type ExistentialDeposit = ExistentialDeposit; + type AccountStore = System; +} +parameter_types! { + pub const ProofLimit: u32 = 1024; + pub const ExpireDuration: u64 = 100; +} +impl Trait for Test { + type Event = (); + type Currency = Balances; + type ProofLimit = ProofLimit; +} +type System = frame_system::Module; +type Balances = pallet_balances::Module; +type AtomicSwap = Module; + +const A: u64 = 1; +const B: u64 = 2; + +pub fn new_test_ext() -> sp_io::TestExternalities { + let mut t = frame_system::GenesisConfig::default().build_storage::().unwrap(); + let genesis = pallet_balances::GenesisConfig:: { + balances: vec![ + (A, 100), + (B, 200), + ], + }; + genesis.assimilate_storage(&mut t).unwrap(); + t.into() +} + +#[test] +fn two_party_successful_swap() { + let mut chain1 = new_test_ext(); + let mut chain2 = new_test_ext(); + + // A generates a random proof. Keep it secret. + let proof: [u8; 2] = [4, 2]; + // The hashed proof is the blake2_256 hash of the proof. This is public. + let hashed_proof = blake2_256(&proof); + + // A creates the swap on chain1. + chain1.execute_with(|| { + AtomicSwap::create_swap( + Origin::signed(A), + B, + hashed_proof.clone(), + 50, + 1000, + ).unwrap(); + + assert_eq!(Balances::free_balance(A), 100 - 50); + assert_eq!(Balances::free_balance(B), 200); + }); + + // B creates the swap on chain2. + chain2.execute_with(|| { + AtomicSwap::create_swap( + Origin::signed(B), + A, + hashed_proof.clone(), + 75, + 1000, + ).unwrap(); + + assert_eq!(Balances::free_balance(A), 100); + assert_eq!(Balances::free_balance(B), 200 - 75); + }); + + // A reveals the proof and claims the swap on chain2. + chain2.execute_with(|| { + AtomicSwap::claim_swap( + Origin::signed(A), + proof.to_vec(), + ).unwrap(); + + assert_eq!(Balances::free_balance(A), 100 + 75); + assert_eq!(Balances::free_balance(B), 200 - 75); + }); + + // B use the revealed proof to claim the swap on chain1. + chain1.execute_with(|| { + AtomicSwap::claim_swap( + Origin::signed(B), + proof.to_vec(), + ).unwrap(); + + assert_eq!(Balances::free_balance(A), 100 - 50); + assert_eq!(Balances::free_balance(B), 200 + 50); + }); +}