code moved

cumulus/Cargo.toml

@@ -2,6 +2,7 @@
 members = [
   "consensus",
   "runtime",
+  "network",
   "test/runtime",
   "test/client",
 ]

cumulus/network/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "cumulus-network"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+description = "Cumulus-specific networking protocol"
+edition = "2018"
+
+[dependencies]
+# substrate deps
+substrate-client = { git = "https://github.com/paritytech/substrate", branch = "bkchr-cumulus-branch" }
+substrate-consensus-common = { git = "https://github.com/paritytech/substrate", branch = "bkchr-cumulus-branch" }
+sr-primitives = { git = "https://github.com/paritytech/substrate", branch = "bkchr-cumulus-branch" }
+
+# polkadot deps
+polkadot-primitives = { git = "https://github.com/paritytech/polkadot", branch = "bkchr-cumulus-branch" }
+polkadot-statement-table = { git = "https://github.com/paritytech/polkadot", branch = "bkchr-cumulus-branch" }
+polkadot-validation = { git = "https://github.com/paritytech/polkadot", branch = "bkchr-cumulus-branch" }
+
+# other deps
+tokio = "0.1.22"
+codec = { package = "parity-scale-codec", version = "1.0.5", features = [ "derive" ] }

cumulus/network/src/lib.rs

@@ -0,0 +1,82 @@
+use substrate_client::error::{Error as ClientError};
+use sr_primitives::traits::{Block as BlockT};
+use substrate_consensus_common::block_validation::{Validation, BlockAnnounceValidator};
+
+use polkadot_primitives::{
+	Hash as PHash, parachain::{CandidateReceipt, ValidatorIndex, ValidatorSignature, ValidatorId},
+};
+use polkadot_statement_table::Statement;
+use polkadot_validation::check_statement;
+
+use codec::{Decode, Encode};
+
+use std::marker::PhantomData;
+
+/// Justification that a parachain block is the parachain block candidate of one of the relay chain
+/// validator.
+#[derive(Encode, Decode)]
+pub struct BlockCandidateJustification {
+	/// Receipt of the parachain block candidate of the signer.
+	candidate_receipt: CandidateReceipt,
+	/// Signer of `signature`.
+	signer: ValidatorIndex,
+	/// Signature of the Candidate statement with `candidate_receipt`.
+	signature: ValidatorSignature,
+	/// The parent block of which the candidate must be include.
+	relay_chain_parent_hash: PHash,
+}
+
+/// Validate that data is a valid justification form a relay-chain validator that the block is a
+/// valid parachain-block candidate.
+pub struct JustifiedBlockAnnounceValidator<B> {
+	authorities: Vec<ValidatorId>,
+	phantom: PhantomData<B>,
+}
+
+impl<B: BlockT> JustifiedBlockAnnounceValidator<B> {
+	pub fn new(authorities: Vec<ValidatorId>) -> Self {
+		Self {
+			authorities,
+			phantom: Default::default(),
+		}
+	}
+}
+
+impl<B: BlockT> BlockAnnounceValidator<B> for JustifiedBlockAnnounceValidator<B> {
+	fn validate(&mut self, header: &B::Header, mut data: &[u8])
+		-> Result<Validation, Box<dyn std::error::Error + Send>>
+	{
+		let justification = BlockCandidateJustification::decode(&mut data)
+			.map_err(|_| Box::new(ClientError::BadJustification(
+				"cannot decode block candidate justification".to_string()
+			)) as Box<_>)?;
+
+		// Check the header in the candidate_receipt match header given header.
+		if header.encode() != justification.candidate_receipt.head_data.0 {
+			return Err(Box::new(ClientError::BadJustification(
+				"block candidate header does not match its justification".to_string()
+			)) as Box<_>)
+		}
+
+		// Check that the signer is a legit validator.
+		let signer = self.authorities.get(justification.signer as usize)
+			.ok_or_else(|| Box::new(ClientError::BadJustification(
+				"block candidate justification signer is a validator index out of bound".to_string()
+			)) as Box<_>)?;
+
+		// Check statement is signed.
+		let statement = Statement::Candidate(justification.candidate_receipt);
+		if !check_statement(
+			&statement,
+			&justification.signature,
+			signer.clone(),
+			&justification.relay_chain_parent_hash
+		) {
+			return Err(Box::new(ClientError::BadJustification(
+				"block candidate justification signature is invalid".to_string()
+			)) as Box<_>)
+		}
+
+		Ok(Validation::Success)
+	}
+}