Downward & Upward messages (#1266)

* Downward messages, the front-end.

* Move types around to make them accessible from Parachains

* Fix compilation

* Fix branch

* Make it compile for Cumulus

* Update the branch names

* Add default generic parameter

* Implement `Partialeq`

* Move upward messages into the `ValidationResult`

* Support disabling of the runtime api

* Update branch

* Adds support for handling downward messages

* Implement sending XCMP messages as up/downward messages

* service: update to latest ServiceBuilder changes

* Make it compile

* Initial commit

Forked at: b2c9c14
Parent branch: origin/master

* Update substrate branch to cecton-update-polkadot-substrate

* Update substrate & polkadot to cumulus-branch

* Reset branch

* Update primitives/src/parachain.rs

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

* Update runtime/common/src/parachains.rs

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

* Update runtime/common/src/parachains.rs

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

* Minor fixes

* Fix wasm build

Co-authored-by: Gav Wood <gavin@parity.io>
Co-authored-by: André Silva <andre.beat@gmail.com>
Co-authored-by: Cecile Tonglet <cecile.tonglet@cecton.com>
Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

Cargo.toml

@@ -26,6 +26,7 @@ members = [
 	"availability-store",
 	"cli",
 	"collator",
+	"core-primitives",
 	"erasure-coding",
 	"network",
 	"network/test",

availability-store/src/lib.rs

@@ -33,7 +33,7 @@ use polkadot_primitives::{
 	},
 };
 use sp_runtime::traits::HashFor;
-use sp_blockchain::{Result as ClientResult};
+use sp_blockchain::Result as ClientResult;
 use client::{
 	BlockchainEvents, BlockBackend,
 };
@@ -58,7 +58,7 @@ use worker::{
 	Worker, WorkerHandle, IncludedParachainBlocks, WorkerMsg, MakeAvailable, Chunks
 };
 
-use store::{Store as InnerStore};
+use store::Store as InnerStore;
 
 const LOG_TARGET: &str = "availability";
 

availability-store/src/store.rs

@@ -18,7 +18,7 @@
 use kvdb_rocksdb::{Database, DatabaseConfig};
 use kvdb::{KeyValueDB, DBTransaction};
 use codec::{Encode, Decode};
-use polkadot_erasure_coding::{self as erasure};
+use polkadot_erasure_coding as erasure;
 use polkadot_primitives::{
 	Hash,
 	parachain::{

collator/src/lib.rs

@@ -56,7 +56,7 @@ use sc_client_api::{StateBackend, BlockchainEvents};
 use sp_blockchain::HeaderBackend;
 use sp_core::Pair;
 use polkadot_primitives::{
-	BlockId, Hash, Block,
+	BlockId, Hash, Block, DownwardMessage,
 	parachain::{
 		self, BlockData, DutyRoster, HeadData, Id as ParaId,
 		PoVBlock, ValidatorId, CollatorPair, LocalValidationData, GlobalValidationSchedule,
@@ -150,6 +150,7 @@ pub trait ParachainContext: Clone {
 		relay_parent: Hash,
 		global_validation: GlobalValidationSchedule,
 		local_validation: LocalValidationData,
+		downward_messages: Vec<DownwardMessage>,
 	) -> Self::ProduceCandidate;
 }
 
@@ -159,6 +160,7 @@ pub async fn collate<P>(
 	local_id: ParaId,
 	global_validation: GlobalValidationSchedule,
 	local_validation_data: LocalValidationData,
+	downward_messages: Vec<DownwardMessage>,
 	mut para_context: P,
 	key: Arc<CollatorPair>,
 ) -> Option<parachain::Collation>
@@ -170,6 +172,7 @@ pub async fn collate<P>(
 		relay_parent,
 		global_validation,
 		local_validation_data,
+		downward_messages,
 	).await?;
 
 	let pov_block = PoVBlock {
@@ -317,6 +320,7 @@ fn build_collator_service<P, C, R, Extrinsic>(
 					Some(local_validation) => local_validation,
 					None => return future::Either::Left(future::ok(())),
 				};
+				let downward_messages = try_fr!(api.downward_messages(&id, para_id));
 
 				let validators = try_fr!(api.validators(&id));
 
@@ -331,6 +335,7 @@ fn build_collator_service<P, C, R, Extrinsic>(
 					para_id,
 					global_validation,
 					local_validation,
+					downward_messages,
 					parachain_context,
 					key,
 				).map(move |collation| {
@@ -470,6 +475,7 @@ mod tests {
 			_relay_parent: Hash,
 			_global: GlobalValidationSchedule,
 			_local_validation: LocalValidationData,
+			_: Vec<DownwardMessage>,
 		) -> Self::ProduceCandidate {
 			// send messages right back.
 			future::ready(Some((

core-primitives/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "polkadot-core-primitives"
+version = "0.7.30"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-std = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+codec = { package = "parity-scale-codec", version = "1.3.0", default-features = false, features = [ "derive" ] }
+
+[features]
+default = [ "std" ]
+std = [
+	"sp-core/std",
+	"sp-runtime/std",
+	"sp-std/std",
+	"codec/std",
+]

core-primitives/src/lib.rs

@@ -0,0 +1,96 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot 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 General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+//! Core Polkadot types.
+//!
+//! These core Polkadot types are used by the relay chain and the Parachains.
+
+use sp_runtime::{generic, MultiSignature, traits::{Verify, BlakeTwo256, IdentifyAccount}};
+
+/// The block number type used by Polkadot.
+/// 32-bits will allow for 136 years of blocks assuming 1 block per second.
+pub type BlockNumber = u32;
+
+/// An instant or duration in time.
+pub type Moment = u64;
+
+/// Alias to type for a signature for a transaction on the relay chain. This allows one of several
+/// kinds of underlying crypto to be used, so isn't a fixed size when encoded.
+pub type Signature = MultiSignature;
+
+/// Alias to the public key used for this chain, actually a `MultiSigner`. Like the signature, this
+/// also isn't a fixed size when encoded, as different cryptos have different size public keys.
+pub type AccountPublic = <Signature as Verify>::Signer;
+
+/// Alias to the opaque account ID type for this chain, actually a `AccountId32`. This is always
+/// 32 bytes.
+pub type AccountId = <AccountPublic as IdentifyAccount>::AccountId;
+
+/// The type for looking up accounts. We don't expect more than 4 billion of them.
+pub type AccountIndex = u32;
+
+/// Identifier for a chain. 32-bit should be plenty.
+pub type ChainId = u32;
+
+/// A hash of some data used by the relay chain.
+pub type Hash = sp_core::H256;
+
+/// Index of a transaction in the relay chain. 32-bit should be plenty.
+pub type Nonce = u32;
+
+/// The balance of an account.
+/// 128-bits (or 38 significant decimal figures) will allow for 10m currency (10^7) at a resolution
+/// to all for one second's worth of an annualised 50% reward be paid to a unit holder (10^11 unit
+/// denomination), or 10^18 total atomic units, to grow at 50%/year for 51 years (10^9 multiplier)
+/// for an eventual total of 10^27 units (27 significant decimal figures).
+/// We round denomination to 10^12 (12 sdf), and leave the other redundancy at the upper end so
+/// that 32 bits may be multiplied with a balance in 128 bits without worrying about overflow.
+pub type Balance = u128;
+
+/// Header type.
+pub type Header = generic::Header<BlockNumber, BlakeTwo256>;
+/// Block type.
+pub type Block = generic::Block<Header, UncheckedExtrinsic>;
+/// Block ID.
+pub type BlockId = generic::BlockId<Block>;
+
+/// Opaque, encoded, unchecked extrinsic.
+pub use sp_runtime::OpaqueExtrinsic as UncheckedExtrinsic;
+
+/// The information that goes alongside a transfer_into_parachain operation. Entirely opaque, it
+/// will generally be used for identifying the reason for the transfer. Typically it will hold the
+/// destination account to which the transfer should be credited. If still more information is
+/// needed, then this should be a hash with the pre-image presented via an off-chain mechanism on
+/// the parachain.
+pub type Remark = [u8; 32];
+
+/// These are special "control" messages that can be passed from the Relaychain to a parachain.
+/// They should be handled by all parachains.
+#[derive(codec::Encode, codec::Decode, Clone, sp_runtime::RuntimeDebug, PartialEq)]
+pub enum DownwardMessage<AccountId = crate::AccountId> {
+	/// Some funds were transferred into the parachain's account. The hash is the identifier that
+	/// was given with the transfer.
+	TransferInto(AccountId, Balance, Remark),
+	/// An opaque blob of data. The relay chain must somehow know how to form this so that the
+	/// destination parachain does something sensible.
+	///
+	/// NOTE: Be very careful not to allow users to place arbitrary size information in here.
+	Opaque(sp_std::vec::Vec<u8>),
+	/// XCMP message for the Parachain.
+	XCMPMessage(sp_std::vec::Vec<u8>),
+}

network/src/protocol/tests.rs

@@ -185,6 +185,9 @@ sp_api::mock_impl_runtime_apis! {
 				parent_hash: Default::default(),
 			}
 		}
+		fn downward_messages(_: ParaId) -> Vec<polkadot_primitives::DownwardMessage> {
+			Vec::new()
+		}
 	}
 }
 

parachain/Cargo.toml

@@ -13,11 +13,11 @@ codec = { package = "parity-scale-codec", version = "1.1.0", default-features =
 sp-std = { package = "sp-std", git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-wasm-interface = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+polkadot-core-primitives = { path = "../core-primitives", default-features = false }
 
 # all optional crates.
 derive_more = { version = "0.99.2", optional = true }
 serde = { version = "1.0.102", default-features = false, features = [ "derive" ], optional = true }
-sp-runtime-interface = { git = "https://github.com/paritytech/substrate", branch = "master", optional = true, default-features = false }
 sp-externalities = { git = "https://github.com/paritytech/substrate", branch = "master", optional = true }
 sc-executor = { git = "https://github.com/paritytech/substrate", branch = "master", optional = true }
 sp-io = { git = "https://github.com/paritytech/substrate", branch = "master", optional = true }
@@ -29,7 +29,7 @@ shared_memory = { version = "0.10.0", optional = true }
 
 [features]
 default = ["std"]
-wasm-api = ["sp-runtime-interface"]
+wasm-api = []
 std = [
 	"codec/std",
 	"derive_more",
@@ -39,8 +39,8 @@ std = [
 	"sp-core/std",
 	"parking_lot",
 	"log",
-	"sp-runtime-interface/std",
 	"sp-externalities",
 	"sc-executor",
 	"sp-io",
+	"polkadot-core-primitives/std",
 ]

parachain/src/primitives.rs

@@ -28,9 +28,8 @@ use serde::{Serialize, Deserialize};
 #[cfg(feature = "std")]
 use sp_core::bytes;
 
-/// The block number of the relay chain.
-/// 32-bits will allow for 136 years of blocks assuming 1 block per second.
-pub type RelayChainBlockNumber = u32;
+/// Block number type used by the relay chain.
+pub use polkadot_core_primitives::BlockNumber as RelayChainBlockNumber;
 
 /// Parachain head data included in the chain.
 #[derive(PartialEq, Eq, Clone, PartialOrd, Ord, Encode, Decode, RuntimeDebug)]
@@ -186,10 +185,6 @@ impl sp_std::convert::TryFrom<u8> for ParachainDispatchOrigin {
 
 /// A message from a parachain to its Relay Chain.
 #[derive(Clone, PartialEq, Eq, Encode, Decode)]
-#[cfg_attr(
-	any(feature = "std", feature = "wasm-api"),
-	derive(sp_runtime_interface::pass_by::PassByCodec,
-))]
 #[cfg_attr(feature = "std", derive(Debug))]
 pub struct UpwardMessage {
 	/// The origin for the message to be sent from.
@@ -212,13 +207,13 @@ pub struct ValidationParams {
 	/// The maximum head-data size permitted, in bytes.
 	pub max_head_data_size: u32,
 	/// The current relay-chain block number.
-	pub relay_chain_height: RelayChainBlockNumber,
+	pub relay_chain_height: polkadot_core_primitives::BlockNumber,
 	/// Whether a code upgrade is allowed or not, and at which height the upgrade
 	/// would be applied after, if so. The parachain logic should apply any upgrade
 	/// issued in this block after the first block
 	/// with `relay_chain_height` at least this value, if `Some`. if `None`, issue
 	/// no upgrade.
-	pub code_upgrade_allowed: Option<RelayChainBlockNumber>,
+	pub code_upgrade_allowed: Option<polkadot_core_primitives::BlockNumber>,
 }
 
 /// The result of parachain validation.
@@ -230,4 +225,10 @@ pub struct ValidationResult {
 	pub head_data: HeadData,
 	/// An update to the validation code that should be scheduled in the relay chain.
 	pub new_validation_code: Option<ValidationCode>,
+	/// Upward messages send by the Parachain.
+	pub upward_messages: Vec<UpwardMessage>,
+	/// Number of downward messages that were processed by the Parachain.
+	///
+	/// It is expected that the Parachain processes them from first to last.
+	pub processed_downward_messages: u32,
 }

parachain/src/wasm_api.rs

@@ -16,29 +16,6 @@
 
 //! Utilities for writing parachain WASM.
 
-#[cfg(any(feature = "std", all(not(feature = "std"), feature = "wasm-api")))]
-use crate::primitives::UpwardMessage;
-#[cfg(any(feature = "std", all(not(feature = "std"), feature = "wasm-api")))]
-use sp_runtime_interface::runtime_interface;
-#[cfg(feature = "std")]
-use sp_externalities::ExternalitiesExt;
-
-/// The parachain api for posting messages.
-// Either activate on `std` to get access to the `HostFunctions` or when `wasm-api` is given and on
-// `no_std`.
-#[cfg(any(feature = "std", all(not(feature = "std"), feature = "wasm-api")))]
-#[runtime_interface]
-pub trait Parachain {
-	/// Post a message to this parachain's relay chain.
-	#[allow(dead_code)]
-	fn post_upward_message(&mut self, msg: UpwardMessage) {
-		self.extension::<crate::wasm_executor::ParachainExt>()
-			.expect("No `ParachainExt` associated with the current context.")
-			.post_upward_message(msg)
-			.expect("Failed to post upward message")
-	}
-}
-
 /// Load the validation params from memory when implementing a Rust parachain.
 ///
 /// Offset and length must have been provided by the validation