feat(RNG): governor for RNG and lookahead

Author: unknownunknown1

contracts/deploy/00-home-chain-arbitration.ts

@@ -22,6 +22,7 @@ const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment)
   const { deployments, getNamedAccounts, getChainId } = hre;
   const { deploy, execute } = deployments;
   const { AddressZero } = hre.ethers.constants;
+  const RNG_LOOKAHEAD = 20;
 
   // fallback to hardhat node signers on local network
   const deployer = (await getNamedAccounts()).deployer ?? (await hre.ethers.getSigners())[0].address;
@@ -65,13 +66,13 @@ const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment)
   const randomizer = randomizerByChain.get(Number(await getChainId())) ?? AddressZero;
   const rng = await deploy("RandomizerRNG", {
     from: deployer,
-    args: [randomizer],
+    args: [randomizer, deployer],
     log: true,
   });
 
   const disputeKit = await deploy("DisputeKitClassic", {
     from: deployer,
-    args: [deployer, AddressZero, rng.address],
+    args: [deployer, AddressZero, rng.address, RNG_LOOKAHEAD],
     log: true,
   });
 

contracts/src/arbitration/dispute-kits/DisputeKitClassic.sol

@@ -71,10 +71,10 @@ contract DisputeKitClassic is BaseDisputeKit, IEvidence {
     uint256 public constant LOSER_STAKE_MULTIPLIER = 20000; // Multiplier of the appeal cost that the loser has to pay as fee stake for a round in basis points. Default is 2x of appeal fee.
     uint256 public constant LOSER_APPEAL_PERIOD_MULTIPLIER = 5000; // Multiplier of the appeal period for the choice that wasn't voted for in the previous round, in basis points. Default is 1/2 of original appeal period.
     uint256 public constant ONE_BASIS_POINT = 10000; // One basis point, for scaling.
-    uint256 public constant RNG_LOOKAHEAD = 20; // Minimum block distance between requesting and obtaining a random number. Arbitrum sequencer finality = 20 blocks.
 
     RNG public rng; // The random number generator
     uint256 public rngRequestedBlock; // The block number requested to the random number.
+    uint256 public rngLookahead; // Minimum block distance between requesting and obtaining a random number.
     uint256 public randomNumber; // The current random number.
     Phase public phase; // Current phase of this dispute kit.
     uint256 public disputesWithoutJurors; // The number of disputes that have not finished drawing jurors.
@@ -117,9 +117,11 @@ contract DisputeKitClassic is BaseDisputeKit, IEvidence {
      *  @param _governor The governor's address.
      *  @param _core The KlerosCore arbitrator.
      *  @param _rng The random number generator.
+     *  @param _rngLookahead Lookahead value for rng.
      */
-    constructor(address _governor, KlerosCore _core, RNG _rng) BaseDisputeKit(_governor, _core) {
+    constructor(address _governor, KlerosCore _core, RNG _rng, uint256 _rngLookahead) BaseDisputeKit(_governor, _core) {
         rng = _rng;
+        rngLookahead = _rngLookahead;
     }
 
     // ************************ //
@@ -142,11 +144,13 @@ contract DisputeKitClassic is BaseDisputeKit, IEvidence {
 
     /** @dev Changes the `_rng` storage variable.
      *  @param _rng The new value for the `RNGenerator` storage variable.
+     *  @param _rngLookahead The new value for the `rngLookahead` storage variable.
      */
-    function changeRandomNumberGenerator(RNG _rng) external onlyByGovernor {
+    function changeRandomNumberGenerator(RNG _rng, uint256 _rngLookahead) external onlyByGovernor {
         rng = _rng;
+        rngLookahead = _rngLookahead;
         if (phase == Phase.generating) {
-            rngRequestedBlock = block.number + RNG_LOOKAHEAD;
+            rngRequestedBlock = block.number + rngLookahead;
             rng.requestRandomness(rngRequestedBlock);
         }
     }
@@ -193,7 +197,7 @@ contract DisputeKitClassic is BaseDisputeKit, IEvidence {
         } else if (core.phase() == KlerosCore.Phase.freezing) {
             if (phase == Phase.resolving) {
                 require(disputesWithoutJurors > 0, "All the disputes have jurors");
-                rngRequestedBlock = core.freezeBlock() + RNG_LOOKAHEAD;
+                rngRequestedBlock = core.freezeBlock() + rngLookahead;
                 rng.requestRandomness(rngRequestedBlock);
                 phase = Phase.generating;
             } else if (phase == Phase.generating) {

contracts/src/arbitration/dispute-kits/DisputeKitSybilResistant.sol

@@ -80,11 +80,11 @@ contract DisputeKitSybilResistant is BaseDisputeKit, IEvidence {
     uint256 public constant LOSER_STAKE_MULTIPLIER = 20000; // Multiplier of the appeal cost that the loser has to pay as fee stake for a round in basis points. Default is 2x of appeal fee.
     uint256 public constant LOSER_APPEAL_PERIOD_MULTIPLIER = 5000; // Multiplier of the appeal period for the choice that wasn't voted for in the previous round, in basis points. Default is 1/2 of original appeal period.
     uint256 public constant ONE_BASIS_POINT = 10000; // One basis point, for scaling.
-    uint256 public constant RNG_LOOKAHEAD = 20; // Minimum block distance between requesting and obtaining a random number. Arbitrum sequencer finality = 20 blocks.
 
     RNG public rng; // The random number generator
     IProofOfHumanity public poh; // The Proof of Humanity registry
     uint256 public rngRequestedBlock; // The block number requested to the random number.
+    uint256 public rngLookahead; // Minimum block distance between requesting and obtaining a random number.
     uint256 public randomNumber; // The current random number.
     Phase public phase; // Current phase of this dispute kit.
     uint256 public disputesWithoutJurors; // The number of disputes that have not finished drawing jurors.
@@ -127,9 +127,18 @@ contract DisputeKitSybilResistant is BaseDisputeKit, IEvidence {
      *  @param _governor The governor's address.
      *  @param _core The KlerosCore arbitrator.
      *  @param _rng The random number generator.
+     *  @param _rngLookahead Lookahead value for rng.
+     *  @param _poh ProofOfHumanity contract.
      */
-    constructor(address _governor, KlerosCore _core, RNG _rng, IProofOfHumanity _poh) BaseDisputeKit(_governor, _core) {
+    constructor(
+        address _governor,
+        KlerosCore _core,
+        RNG _rng,
+        uint256 _rngLookahead,
+        IProofOfHumanity _poh
+    ) BaseDisputeKit(_governor, _core) {
         rng = _rng;
+        rngLookahead = _rngLookahead;
         poh = _poh;
     }
 
@@ -153,11 +162,13 @@ contract DisputeKitSybilResistant is BaseDisputeKit, IEvidence {
 
     /** @dev Changes the `_rng` storage variable.
      *  @param _rng The new value for the `RNGenerator` storage variable.
+     *  @param _rngLookahead The new value for the `rngLookahead` storage variable.
      */
-    function changeRandomNumberGenerator(RNG _rng) external onlyByGovernor {
+    function changeRandomNumberGenerator(RNG _rng, uint256 _rngLookahead) external onlyByGovernor {
         rng = _rng;
+        rngLookahead = _rngLookahead;
         if (phase == Phase.generating) {
-            rngRequestedBlock = block.number + RNG_LOOKAHEAD;
+            rngRequestedBlock = block.number + rngLookahead;
             rng.requestRandomness(rngRequestedBlock);
         }
     }
@@ -211,7 +222,7 @@ contract DisputeKitSybilResistant is BaseDisputeKit, IEvidence {
         } else if (core.phase() == KlerosCore.Phase.freezing) {
             if (phase == Phase.resolving) {
                 require(disputesWithoutJurors > 0, "All the disputes have jurors");
-                rngRequestedBlock = core.freezeBlock() + RNG_LOOKAHEAD;
+                rngRequestedBlock = core.freezeBlock() + rngLookahead;
                 rng.requestRandomness(rngRequestedBlock);
                 phase = Phase.generating;
             } else if (phase == Phase.generating) {

contracts/src/rng/RandomizerRNG.sol

@@ -11,18 +11,31 @@ import "./IRandomizer.sol";
  */
 contract RandomizerRNG is RNG {
     uint256 public constant CALLBACK_GAS_LIMIT = 50000;
-    // TODO: should the owner be KlerosLiquid by default?
-    address public owner = msg.sender; // The address that can withdraw funds.
+    address public governor; // The address that can withdraw funds.
 
     IRandomizer public randomizer; // Randomizer address.
     mapping(uint128 => uint256) public randomNumbers; // randomNumbers[requestID] is the random number for this request id, 0 otherwise.
     mapping(address => uint128) public requesterToID; // Maps the requester to his latest request ID.
 
+    modifier onlyByGovernor() {
+        require(governor == msg.sender, "Governor only");
+        _;
+    }
+
     /** @dev Constructor.
      *  @param _randomizer Randomizer contract.
+     *  @param _governor Governor of the contract.
      */
-    constructor(IRandomizer _randomizer) {
+    constructor(IRandomizer _randomizer, address _governor) {
         randomizer = _randomizer;
+        governor = _governor;
+    }
+
+    /** @dev Changes the governor of the contract.
+     *  @param _governor The new governor.
+     */
+    function changeGovernor(address _governor) external onlyByGovernor {
+        governor = _governor;
     }
 
     /**
@@ -52,11 +65,10 @@ contract RandomizerRNG is RNG {
     }
 
     /**
-     *  @dev Allows the owner to withdraw randomizer funds.
+     *  @dev Allows the governor to withdraw randomizer funds.
      *  @param _amount Amount to withdraw in wei.
      */
-    function randomizerWithdraw(uint256 _amount) external {
-        require(msg.sender == owner, "Only owner allowed");
+    function randomizerWithdraw(uint256 _amount) external onlyByGovernor {
         randomizer.clientWithdrawTo(msg.sender, _amount);
     }
 }

contracts/test/arbitration/draw.ts

@@ -103,12 +103,14 @@ describe("Draw Benchmark", async () => {
     await network.provider.send("evm_increaseTime", [2000]); // Wait for minStakingTime
     await network.provider.send("evm_mine");
     await core.passPhase(); // Staking -> Freezing
-    for (let index = 0; index < 20; index++) {
-      await network.provider.send("evm_mine"); // Wait for 20 blocks finality
+
+    const lookahead = await disputeKit.rngLookahead();
+    for (let index = 0; index < lookahead; index++) {
+      await network.provider.send("evm_mine");
     }
     await disputeKit.passPhase(); // Resolving -> Generating
-    for (let index = 0; index < 20; index++) {
-      await network.provider.send("evm_mine"); // RNG lookahead, TODO: remove this for RandomizerRNG
+    for (let index = 0; index < lookahead; index++) {
+      await network.provider.send("evm_mine");
     }
     await randomizer.relay(rng.address, 0, ethers.utils.randomBytes(32));
     await disputeKit.passPhase(); // Generating -> Drawing

contracts/test/arbitration/index.ts

@@ -7,6 +7,8 @@ const WINNER_STAKE_MULTIPLIER = 3000;
 const LOSER_STAKE_MULTIPLIER = 7000;
 const MULTIPLIER_DENOMINATOR = 10000;
 
+const RNG_LOOKAHEAD = 20;
+
 describe("DisputeKitClassic", async () => {
   // eslint-disable-next-line no-unused-vars
   let deployer;
@@ -78,7 +80,8 @@ async function deployContracts(deployer) {
   const disputeKit = await disputeKitFactory.deploy(
     deployer.address,
     ethers.constants.AddressZero, // KlerosCore is set later once it is deployed
-    rng.address
+    rng.address,
+    RNG_LOOKAHEAD
   );
   await disputeKit.deployed();
 

contracts/test/arbitration/unstake.ts

@@ -53,13 +53,15 @@ describe("Unstake juror", async () => {
 
     await network.provider.send("evm_increaseTime", [2000]); // Wait for minStakingTime
     await network.provider.send("evm_mine");
+
+    const lookahead = await disputeKit.rngLookahead();
     await core.passPhase(); // Staking -> Freezing
-    for (let index = 0; index < 20; index++) {
-      await network.provider.send("evm_mine"); // Wait for 20 blocks finality
+    for (let index = 0; index < lookahead; index++) {
+      await network.provider.send("evm_mine");
     }
     await disputeKit.passPhase(); // Resolving -> Generating
-    for (let index = 0; index < 20; index++) {
-      await network.provider.send("evm_mine"); // RNG lookahead, TODO: remove this for RandomizerRNG
+    for (let index = 0; index < lookahead; index++) {
+      await network.provider.send("evm_mine");
     }
     await randomizer.relay(rng.address, 0, ethers.utils.randomBytes(32));
     await disputeKit.passPhase(); // Generating -> Drawing

contracts/test/integration/index.ts

@@ -138,12 +138,12 @@ describe("Integration tests", async () => {
     expect(await core.phase()).to.equal(Phase.freezing);
     console.log("KC phase: %d, DK phase: ", await core.phase(), await disputeKit.phase());
 
-    await mineBlocks(20); // Wait for 20 blocks finality
+    await mineBlocks(await disputeKit.rngLookahead());
     await disputeKit.passPhase(); // Resolving -> Generating
     expect(await disputeKit.phase()).to.equal(DisputeKitPhase.generating);
     console.log("KC phase: %d, DK phase: ", await core.phase(), await disputeKit.phase());
 
-    await mineBlocks(20); // Wait for RNG lookahead, TODO: remove this for RandomizerRNG
+    await mineBlocks(await disputeKit.rngLookahead());
     await randomizer.relay(rng.address, 0, ethers.utils.randomBytes(32));
     await disputeKit.passPhase(); // Generating -> Drawing
     expect(await disputeKit.phase()).to.equal(DisputeKitPhase.drawing);