Duty roster for validators (MVP)

wasm-runtime/polkadot/src/runtime/governance.rs

@@ -43,7 +43,7 @@ pub fn approval_ppm_required() -> u32 {
 
 /// The number of concrete validator approvals required for a proposal to pass.
 pub fn approvals_required() -> u32 {
- approval_ppm_required() * session::validator_count() as u32 / 1000
+ approval_ppm_required() * session::validator_count() / 1000
 }
 
 pub mod public {
@@ -152,7 +152,7 @@ mod tests {
  with_externalities(&mut t, || {
  assert_eq!(staking::era_length(), 1u64);
  assert_eq!(staking::current_era(), 1u64);
- assert_eq!(session::validator_count(), 3usize);
+ assert_eq!(session::validator_count(), 3u32);
  assert_eq!(session::validators(), vec![one.clone(), two.clone(), three.clone()]);
  assert!(!session::validators().into_iter().position(|v| &v == &one).is_none());
 
@@ -178,7 +178,7 @@ mod tests {
  with_externalities(&mut t, || {
  assert_eq!(staking::era_length(), 1u64);
  assert_eq!(staking::current_era(), 1u64);
- assert_eq!(session::validator_count(), 3usize);
+ assert_eq!(session::validator_count(), 3u32);
  assert_eq!(session::validators(), vec![one.clone(), two.clone(), three.clone()]);
  assert!(!session::validators().into_iter().position(|v| &v == &one).is_none());
 
@@ -213,7 +213,7 @@ mod tests {
  with_externalities(&mut t, || {
  assert_eq!(staking::era_length(), 1u64);
  assert_eq!(staking::current_era(), 1u64);
- assert_eq!(session::validator_count(), 3usize);
+ assert_eq!(session::validator_count(), 3u32);
  assert_eq!(session::validators(), vec![one.clone(), two.clone(), three.clone()]);
  assert!(!session::validators().into_iter().position(|v| &v == &one).is_none());
 
@@ -239,7 +239,7 @@ mod tests {
  with_externalities(&mut t, || {
  assert_eq!(staking::era_length(), 1u64);
  assert_eq!(staking::current_era(), 1u64);
- assert_eq!(session::validator_count(), 3usize);
+ assert_eq!(session::validator_count(), 3u32);
  assert_eq!(session::validators(), vec![one.clone(), two.clone(), three.clone()]);
  assert!(!session::validators().into_iter().position(|v| &v == &one).is_none());
 
@@ -266,7 +266,7 @@ mod tests {
  with_externalities(&mut t, || {
  assert_eq!(staking::era_length(), 1u64);
  assert_eq!(staking::current_era(), 1u64);
- assert_eq!(session::validator_count(), 3usize);
+ assert_eq!(session::validator_count(), 3u32);
  assert_eq!(session::validators(), vec![one.clone(), two.clone(), three.clone()]);
  assert!(!session::validators().into_iter().position(|v| &v == &one).is_none());
 
@@ -294,7 +294,7 @@ mod tests {
  with_externalities(&mut t, || {
  assert_eq!(staking::era_length(), 1u64);
  assert_eq!(staking::current_era(), 1u64);
- assert_eq!(session::validator_count(), 3usize);
+ assert_eq!(session::validator_count(), 3u32);
  assert_eq!(session::validators(), vec![one.clone(), two.clone(), three.clone()]);
  assert!(!session::validators().into_iter().position(|v| &v == &one).is_none());
 
@@ -324,7 +324,7 @@ mod tests {
  with_externalities(&mut t, || {
  assert_eq!(staking::era_length(), 1u64);
  assert_eq!(staking::current_era(), 1u64);
- assert_eq!(session::validator_count(), 3usize);
+ assert_eq!(session::validator_count(), 3u32);
  assert_eq!(session::validators(), vec![one.clone(), two.clone(), three.clone()]);
  assert!(!session::validators().into_iter().position(|v| &v == &one).is_none());
 
@@ -348,7 +348,7 @@ mod tests {
  with_externalities(&mut t, || {
  assert_eq!(staking::era_length(), 1u64);
  assert_eq!(staking::current_era(), 1u64);
- assert_eq!(session::validator_count(), 3usize);
+ assert_eq!(session::validator_count(), 3u32);
  assert_eq!(session::validators(), vec![one.clone(), two.clone(), three.clone()]);
  assert!(!session::validators().into_iter().position(|v| &v == &one).is_none());
 

wasm-runtime/polkadot/src/runtime/mod.rs

@@ -28,10 +28,10 @@ pub mod timestamp;
 pub mod session;
 #[allow(unused)]
 pub mod governance;
+#[allow(unused)]
+pub mod parachains;
 
 // TODO: polkadao
-// TODO: parachains
-
 
 #[cfg(feature = "with-std")]
 pub mod genesismap;

wasm-runtime/polkadot/src/runtime/parachains.rs

@@ -0,0 +1,143 @@
+// Copyright 2017 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/>.
+
+//! Main parachains logic. For now this is just the determination of which validators do what.
+
+use runtime_std::mem;
+use codec::{Slicable, Joiner};
+use support::{Hashable, with_env, storage};
+use runtime::session;
+
+const PARACHAIN_COUNT: &[u8] = b"par:cou";
+
+/// Identifier for a chain, either one of a number of parachains or the relay chain.
+#[derive(Copy, Clone, PartialEq)]
+#[cfg_attr(test, derive(Debug))]
+pub enum Chain {
+ /// The relay chain.
+ Relay,
+ /// A parachain of the given index.
+ Parachain(u32),
+}
+
+/// The duty roster specifying what jobs each validator must do.
+#[derive(Clone, PartialEq)]
+#[cfg_attr(test, derive(Default, Debug))]
+pub struct DutyRoster {
+ /// Lookup from validator index to chain on which that validator has a duty to validate.
+ pub validator_duty: Vec<Chain>,
+ /// Lookup from validator index to chain on which that validator has a duty to guarantee
+ /// availability.
+ pub guarantor_duty: Vec<Chain>,
+}
+
+/// Get the number of parachains registered at present.
+pub fn parachain_count() -> u32 {
+ storage::get_or(PARACHAIN_COUNT, 0)
+}
+
+/// Calculate the current block's duty roster.
+pub fn calculate_duty_roster() -> DutyRoster {
+ let parachain_count = parachain_count();
+ let validator_count = session::validator_count() as u32;
+ let validators_per_parachain = (validator_count - 1) / parachain_count;
+ let validators_on_relay = validator_count - validators_per_parachain * parachain_count;
+
+ let mut roles_val = (0..validator_count).map(|i| match i {
+ i if i < parachain_count * validators_per_parachain => Chain::Parachain(i / validators_per_parachain as u32),
+ _ => Chain::Relay,
+ }).collect::<Vec<_>>();
+ let mut roles_gua = roles_val.clone();
+
+ let h = with_env(|e| e.parent_hash.clone());
+ let mut seed = vec![].join(&h).join(b"validator_role_pairs").blake2_256();
+
+ // shuffle
+ for i in 0..(validator_count - 1) {
+ // 8 bytes of entropy used per cycle, 32 bytes entropy per hash
+ let offset = (i * 8 % 32) as usize;
+
+ // number of roles remaining to select from.
+ let remaining = (validator_count - i) as usize;
+
+ // 4 * 2 32-bit ints per 256-bit seed.
+ let val_index = u32::from_slice(&seed[offset..offset + 4]).expect("using 4 bytes for a 32-byte quantity") as usize % remaining;
+ let gua_index = u32::from_slice(&seed[offset + 4..offset + 8]).expect("using 4 bytes for a 32-byte quantity") as usize % remaining;
+
+ if offset == 24 {
+ // into the last 8 bytes - rehash to gather new entropy
+ seed = seed.blake2_256();
+ }
+
+ // exchange last item with randomly chosen first.
+ roles_val.swap(remaining - 1, val_index);
+ roles_gua.swap(remaining - 1, gua_index);
+ }
+
+ DutyRoster {
+ validator_duty: roles_val,
+ guarantor_duty: roles_gua,
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use runtime_std::{with_externalities, twox_128, TestExternalities};
+ use codec::{KeyedVec, Joiner};
+ use support::{one, two, with_env};
+ use primitives::AccountID;
+ use runtime::{consensus, session};
+
+ fn simple_setup() -> TestExternalities {
+ TestExternalities { storage: map![
+ twox_128(b"ses:val:len").to_vec() => vec![].join(&8u32),
+ twox_128(b"par:cou").to_vec() => vec![].join(&2u32)
+ ], }
+ }
+
+ #[test]
+ fn should_work() {
+ let mut t = simple_setup();
+ with_externalities(&mut t, || {
+ let check_roster = |duty_roster: &DutyRoster| {
+ assert_eq!(duty_roster.validator_duty.len(), 8);
+ assert_eq!(duty_roster.guarantor_duty.len(), 8);
+ for i in 0..2 {
+ assert_eq!(duty_roster.validator_duty.iter().filter(|&&j| j == Chain::Parachain(i)).count(), 3);
+ assert_eq!(duty_roster.guarantor_duty.iter().filter(|&&j| j == Chain::Parachain(i)).count(), 3);
+ }
+ assert_eq!(duty_roster.validator_duty.iter().filter(|&&j| j == Chain::Relay).count(), 2);
+ assert_eq!(duty_roster.guarantor_duty.iter().filter(|&&j| j == Chain::Relay).count(), 2);
+ };
+
+ with_env(|e| e.parent_hash = [0u8; 32]);
+ let duty_roster_0 = calculate_duty_roster();
+ check_roster(&duty_roster_0);
+
+ with_env(|e| e.parent_hash = [1u8; 32]);
+ let duty_roster_1 = calculate_duty_roster();
+ check_roster(&duty_roster_1);
+ assert!(duty_roster_0 != duty_roster_1);
+
+ with_env(|e| e.parent_hash = [2u8; 32]);
+ let duty_roster_2 = calculate_duty_roster();
+ check_roster(&duty_roster_2);
+ assert!(duty_roster_0 != duty_roster_2);
+ assert!(duty_roster_1 != duty_roster_2);
+ });
+ }
+}

wasm-runtime/polkadot/src/runtime/session.rs

@@ -46,8 +46,8 @@ pub fn length() -> BlockNumber {
 }
 
 /// The number of validators currently.
-pub fn validator_count() -> usize {
- ValidatorStorageVec::count() as usize
+pub fn validator_count() -> u32 {
+ ValidatorStorageVec::count() as u32
 }
 
 /// The current era index.

wasm-runtime/polkadot/src/runtime/system.rs

@@ -60,41 +60,24 @@ pub mod internal {
  // populate environment from header.
  with_env(|e| {
  e.block_number = block.header.number;
+ e.parent_hash = block.header.parent_hash;
  });
 
- let ref header = block.header;
-
- // check parent_hash is correct.
- assert!(
- header.number > 0 && block_hash(header.number - 1) == header.parent_hash,
- "Parent hash should be valid."
- );
-
- // check transaction trie root represents the transactions.
- let txs = block.transactions.iter().map(Slicable::to_vec).collect::<Vec<_>>();
- let txs = txs.iter().map(Vec::as_slice).collect::<Vec<_>>();
- let txs_root = enumerated_trie_root(&txs);
- debug_assert_hash(&header.transaction_root, &txs_root);
- assert!(header.transaction_root == txs_root, "Transaction trie root must be valid.");
+ // any initial checks
+ initial_checks(&block);
 
  // execute transactions
- for tx in &block.transactions {
- super::execute_transaction(tx);
- }
+ block.transactions.iter().for_each(super::execute_transaction);
 
+ // post-transactional book-keeping.
  staking::internal::check_new_era();
  session::internal::check_rotate_session();
 
  // any final checks
  final_checks(&block);
 
- // check storage root.
- let storage_root = storage_root();
- debug_assert_hash(&header.state_root, &storage_root);
- assert!(header.state_root == storage_root, "Storage root must match that calculated.");
-
  // any stuff that we do after taking the storage root.
- post_finalise(header);
+ post_finalise(&block.header);
  }
 
  /// Execute a transaction outside of the block execution function.
@@ -103,6 +86,7 @@ pub mod internal {
  // populate environment from header.
  with_env(|e| {
  e.block_number = header.number;
+ e.parent_hash = header.parent_hash;
  mem::swap(&mut header.digest, &mut e.digest);
  });
 
@@ -129,17 +113,6 @@ pub mod internal {
 
  header
  }
-
- #[cfg(feature = "with-std")]
- fn debug_assert_hash(given: &Hash, expected: &Hash) {
- use support::HexDisplay;
- if given != expected {
- println!("Hash: given={}, expected={}", HexDisplay::from(given), HexDisplay::from(expected));
- }
- }
-
- #[cfg(not(feature = "with-std"))]
- fn debug_assert_hash(_given: &Hash, _expected: &Hash) {}
 }
 
 fn execute_transaction(utx: &UncheckedTransaction) {
@@ -160,10 +133,35 @@ fn execute_transaction(utx: &UncheckedTransaction) {
  tx.function.dispatch(&tx.signed, &tx.input_data);
 }
 
-fn final_checks(_block: &Block) {
+fn initial_checks(block: &Block) {
+ let ref header = block.header;
+
+ // check parent_hash is correct.
+ assert!(
+ header.number > 0 && block_hash(header.number - 1) == header.parent_hash,
+ "Parent hash should be valid."
+ );
+
+ // check transaction trie root represents the transactions.
+ let txs = block.transactions.iter().map(Slicable::to_vec).collect::<Vec<_>>();
+ let txs = txs.iter().map(Vec::as_slice).collect::<Vec<_>>();
+ let txs_root = enumerated_trie_root(&txs);
+ debug_assert_hash(&header.transaction_root, &txs_root);
+ assert!(header.transaction_root == txs_root, "Transaction trie root must be valid.");
+}
+
+fn final_checks(block: &Block) {
+ let ref header = block.header;
+
+ // check digest
  with_env(|e| {
- assert!(_block.header.digest == e.digest);
+ assert!(header.digest == e.digest);
  });
+
+ // check storage root.
+ let storage_root = storage_root();
+ debug_assert_hash(&header.state_root, &storage_root);
+ assert!(header.state_root == storage_root, "Storage root must match that calculated.");
 }
 
 fn post_finalise(header: &Header) {
@@ -172,6 +170,17 @@ fn post_finalise(header: &Header) {
  storage::put(&header.number.to_keyed_vec(BLOCK_HASH_AT), &header.blake2_256());
 }
 
+#[cfg(feature = "with-std")]
+fn debug_assert_hash(given: &Hash, expected: &Hash) {
+ use support::HexDisplay;
+ if given != expected {
+ println!("Hash: given={}, expected={}", HexDisplay::from(given), HexDisplay::from(expected));
+ }
+}
+
+#[cfg(not(feature = "with-std"))]
+fn debug_assert_hash(_given: &Hash, _expected: &Hash) {}
+
 #[cfg(test)]
 mod tests {
  use super::*;

wasm-runtime/polkadot/src/support/environment.rs

@@ -21,13 +21,15 @@ use runtime_std::mem;
 use runtime_std::cell::RefCell;
 use runtime_std::rc::Rc;
 
-use primitives::{BlockNumber, Digest};
+use primitives::{BlockNumber, Digest, Hash};
 
 #[derive(Default)]
 /// The information that can be accessed globally.
 pub struct Environment {
  /// The current block number.
  pub block_number: BlockNumber,
+ /// The current block's parent hash.
+ pub parent_hash: Hash,
  /// The current block digest.
  pub digest: Digest,
 }