Finalize Uniswap Oracle

Signed-off-by: AlienTornadosaurusHex <>

src/v2/FeeOracleManager.sol

@@ -14,7 +14,7 @@ import { ITornadoInstance } from "tornado-anonymity-mining/contracts/interfaces/
 
 // Local Imports
 
-import { InstanceRegistry } from "../v1/tornado-proxy/InstanceRegistry.sol";
+import { InstanceRegistry } from "./InstanceRegistry.sol";
 
 import { IFeeOracle } from "./interfaces/IFeeOracle.sol";
 
@@ -31,13 +31,20 @@ struct FeeData {
  * FeeOracleManager (formerly FeeManager).
  */
 contract FeeManagerLegacyStorage {
-    uint24 public deprecatedUniswapTornPoolSwappingFee;
+    /* @dev From first contract */
-    uint32 public deprecatedUniswapTimePeriod;
+    uint24 private _deprecatedUniswapTornPoolSwappingFee;
 
+    /* @dev From first contract */
+    uint32 private _deprecatedUniswapTimePeriod;
+
+    /* @dev From first contract, the only value we keep alive */
     uint24 public feeUpdateInterval;
 
-    mapping(ITornadoInstance => uint160) public oldFeesForInstance;
+    /* @dev From first contract, only used for initialization to preserve old values in the moment */
-    mapping(ITornadoInstance => uint256) public oldFeesForInstanceUpdateTime;
+    mapping(ITornadoInstance => uint160) internal _oldFeesForInstance;
+
+    /* @dev From first contract, only used for initialization to preserve old values in the moment */
+    mapping(ITornadoInstance => uint256) internal _oldFeesForInstanceUpdateTime;
 }
 
 /**
@@ -50,14 +57,14 @@ contract FeeOracleManager is FeeManagerLegacyStorage, Initializable {
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ VARIABLES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
     /* @dev Divide protocol fee by this to get the percent value */
-    uint64 public constant PROTOCOL_FEE_DIVISOR = 1 ether;
+    uint64 public constant FEE_PERCENT_DIVISOR = 1 ether;
-
-    /* @dev The address of the TORN token */
-    address public immutable tornTokenAddress;
 
     /* @dev The Governance Proxy address */
     address public immutable governanceProxyAddress;
 
+    /* @dev The TORN token */
+    IERC20 public immutable torn;
+
     /* @dev The InstanceRegistry contract */
     InstanceRegistry public instanceRegistry;
 
@@ -69,14 +76,16 @@ contract FeeOracleManager is FeeManagerLegacyStorage, Initializable {
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EVENTS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
+    event FeeUpdateIntervalUpdated(uint24 newLimit);
     event FeeUpdated(address indexed instance, uint256 newFee);
-    event NewOracleSet(address indexed instance, address oracle);
+    event OracleUpdated(address indexed instance, address oracle);
-    event NewFeeUpdateIntervalSet(uint24 limit);
+    event InstanceFeePercentUpdated(address indexed instance, uint64 newFeePercent);
+    event InstanceRegistryUpdated(address newAddress);
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ LOGIC ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
     constructor(address _tornTokenAddress, address _governanceProxyAddress) public {
-        tornTokenAddress = _tornTokenAddress;
+        torn = IERC20(_tornTokenAddress);
         governanceProxyAddress = _governanceProxyAddress;
     }
 
@@ -90,43 +99,46 @@ contract FeeOracleManager is FeeManagerLegacyStorage, Initializable {
      * making sure to not reference old data anywhere.
      */
     function initialize(
-        address _uniswapPoolFeeOracle,
+        address _uniswapV3FeeOracle,
         address _instanceRegistryAddress,
         address[] calldata _instanceAddresses,
         uint256[] calldata _feePercents
     ) external onlyGovernance initializer {
+        // Get num of existing instances
         uint256 numInstances = _instanceAddresses.length;
 
         for (uint256 i = 0; i < numInstances; i++) {
+            // For each instance
             ITornadoInstance instance = ITornadoInstance(_instanceAddresses[i]);
 
+            // Store it's old data and the percent fees which will Governance will command
             feeDataForInstance[instance] = FeeData({
-                feeAmount: oldFeesForInstance[instance],
+                feeAmount: _oldFeesForInstance[instance],
                 feePercent: uint64(_feePercents[i]),
-                lastUpdated: uint32(oldFeesForInstanceUpdateTime[instance])
+                lastUpdated: uint32(_oldFeesForInstanceUpdateTime[instance])
             });
 
-            instanceFeeOracles[instance] = IFeeOracle(_uniswapPoolFeeOracle);
+            // All old pools use the uniswap fee oracle
+            instanceFeeOracles[instance] = IFeeOracle(_uniswapV3FeeOracle);
         }
 
+        // Finally also store the instance registry
         instanceRegistry = InstanceRegistry(_instanceRegistryAddress);
     }
 
     function instanceFeeWithUpdate(ITornadoInstance _instance) public virtual returns (uint160) {
-        FeeData memory feeData = feeDataForInstance[_instance];
+        return updateFee(_instance, true);
-
-        if (feeUpdateInterval < now - feeData.lastUpdated) {
-            feeData.feeAmount = updateFee(_instance);
-        }
-
-        return feeData.feeAmount;
     }
 
-    function updateAllFees() public virtual returns (uint160[] memory newFees) {
+    function updateAllFees(bool _respectFeeUpdateInterval)
-        return updateFees(instanceRegistry.getAllInstanceAddresses());
+        public
+        virtual
+        returns (uint160[] memory newFees)
+    {
+        return updateFees(instanceRegistry.getAllInstances(), _respectFeeUpdateInterval);
     }
 
-    function updateFees(ITornadoInstance[] memory _instances)
+    function updateFees(ITornadoInstance[] memory _instances, bool _respectFeeUpdateInterval)
         public
         virtual
         returns (uint160[] memory newFees)
@@ -136,49 +148,74 @@ contract FeeOracleManager is FeeManagerLegacyStorage, Initializable {
         newFees = new uint160[](numInstances);
 
         for (uint256 i = 0; i < numInstances; i++) {
-            newFees[i] = updateFee(_instances[i]);
+            newFees[i] = updateFee(_instances[i], _respectFeeUpdateInterval);
         }
     }
 
-    function updateFee(ITornadoInstance _instance) public virtual returns (uint160 newFee) {
+    function updateFee(ITornadoInstance _instance, bool _respectFeeUpdateInterval)
-        // This will revert if no contract is set
+        public
-        newFee = instanceFeeOracles[_instance].getFee();
+        virtual
+        returns (uint160)
+    {
+        // First get fee data
+        FeeData memory feeData = feeDataForInstance[_instance];
 
-        feeDataForInstance[_instance] = FeeData({
+        // Now update if we do not respect the interval or we respect it and are in the interval
-            feeAmount: newFee,
+        if (!_respectFeeUpdateInterval || feeUpdateInterval < -feeData.lastUpdated + now) {
-            feePercent: feeDataForInstance[_instance].feePercent,
+            // This will revert if no contract is set
-            lastUpdated: uint32(now)
+            feeData.feeAmount = instanceFeeOracles[_instance].getFee(
-        });
+                torn,
+                _instance,
+                instanceRegistry.getInstanceData(_instance),
+                feeData.feePercent,
+                FEE_PERCENT_DIVISOR
+            );
 
-        emit FeeUpdated(address(_instance), newFee);
+            // Store
+            feeDataForInstance[_instance] = FeeData({
+                feeAmount: feeData.feeAmount,
+                feePercent: feeData.feePercent,
+                lastUpdated: uint32(now)
+            });
 
-        return newFee;
+            // Log
+            emit FeeUpdated(address(_instance), feeData.feeAmount);
+        }
+
+        // In any case return a value
+        return feeData.feeAmount;
     }
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SETTERS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
-    function setInstanceRegistry(address _newInstanceRegistryAddress) external onlyGovernance {
+    function setInstanceRegistry(address _newInstanceRegistryProxyAddress) external onlyGovernance {
-        instanceRegistry = InstanceRegistry(_newInstanceRegistryAddress);
+        instanceRegistry = InstanceRegistry(_newInstanceRegistryProxyAddress);
+        emit InstanceRegistryUpdated(_newInstanceRegistryProxyAddress);
     }
 
     function setFeeOracle(address _instanceAddress, address _oracleAddress) external onlyGovernance {
         ITornadoInstance instance = ITornadoInstance(_instanceAddress);
         IFeeOracle oracle = IFeeOracle(_oracleAddress);
+        FeeData memory feeData = feeDataForInstance[instance];
 
         // Reverts if no oracle or does not conform to interface
-        uint160 fee = oracle.getFee();
+        uint160 fee = oracle.getFee(
+            torn,
+            instance,
+            instanceRegistry.getInstanceData(instance),
+            feeData.feePercent,
+            FEE_PERCENT_DIVISOR
+        );
 
         // Ok, set the oracle
         instanceFeeOracles[instance] = oracle;
 
         // Note down updated fee
-        feeDataForInstance[instance] = FeeData({
+        feeDataForInstance[instance] =
-            feeAmount: fee,
+            FeeData({ feeAmount: fee, feePercent: feeData.feePercent, lastUpdated: uint32(now) });
-            feePercent: feeDataForInstance[instance].feePercent,
-            lastUpdated: uint32(now)
-        });
 
-        emit NewOracleSet(_instanceAddress, _oracleAddress);
+        // Logs
+        emit OracleUpdated(_instanceAddress, _oracleAddress);
         emit FeeUpdated(_instanceAddress, fee);
     }
 
@@ -187,11 +224,12 @@ contract FeeOracleManager is FeeManagerLegacyStorage, Initializable {
         onlyGovernance
     {
         feeDataForInstance[_instance].feePercent = _newFeePercent;
+        emit InstanceFeePercentUpdated(address(_instance), _newFeePercent);
     }
 
     function setFeeUpdateInterval(uint24 newLimit) external onlyGovernance {
         feeUpdateInterval = newLimit;
-        emit NewFeeUpdateIntervalSet(newLimit);
+        emit FeeUpdateIntervalUpdated(newLimit);
     }
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GETTERS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
@@ -201,7 +239,13 @@ contract FeeOracleManager is FeeManagerLegacyStorage, Initializable {
     }
 
     function getUpdatedFeeForInstance(ITornadoInstance instance) public view virtual returns (uint160) {
-        return instanceFeeOracles[instance].getFee();
+        return instanceFeeOracles[instance].getFee(
+            torn,
+            instance,
+            instanceRegistry.getInstanceData(instance),
+            feeDataForInstance[instance].feePercent,
+            FEE_PERCENT_DIVISOR
+        );
     }
 
     function getLastFeeForInstance(ITornadoInstance instance) public view virtual returns (uint160) {
@@ -212,17 +256,25 @@ contract FeeOracleManager is FeeManagerLegacyStorage, Initializable {
         return feeDataForInstance[instance].lastUpdated;
     }
 
-    function getFeeDeviations() public view virtual returns (int256[] memory results) {
+    function getFeeDeviations() public view virtual returns (int256[] memory deviations) {
-        ITornadoInstance[] memory instances = instanceRegistry.getAllInstanceAddresses();
+        ITornadoInstance[] memory instances = instanceRegistry.getAllInstances();
 
         uint256 numInstances = instances.length;
 
-        results = new int256[](numInstances);
+        deviations = new int256[](numInstances);
 
         for (uint256 i = 0; i < numInstances; i++) {
             ITornadoInstance instance = instances[i];
 
-            uint256 marketFee = instanceFeeOracles[instance].getFee();
+            FeeData memory feeData = feeDataForInstance[instance];
+
+            uint256 marketFee = instanceFeeOracles[instance].getFee(
+                torn,
+                instance,
+                instanceRegistry.getInstanceData(instance),
+                feeData.feePercent,
+                FEE_PERCENT_DIVISOR
+            );
 
             int256 deviation;
 
@@ -230,7 +282,7 @@ contract FeeOracleManager is FeeManagerLegacyStorage, Initializable {
                 deviation = int256((feeDataForInstance[instance].feeAmount * 1000) / marketFee) - 1000;
             }
 
-            results[i] = deviation;
+            deviations[i] = deviation;
         }
     }
 }

src/v2/InstanceRegistry.sol

@@ -16,6 +16,7 @@ import { ITornadoInstance } from "tornado-anonymity-mining/contracts/interfaces/
 
 // Local imports
 
+import { NameEncoder } from "./libraries/NameEncoder.sol";
 import { TornadoRouter } from "./TornadoRouter.sol";
 
 /**
@@ -23,17 +24,18 @@ import { TornadoRouter } from "./TornadoRouter.sol";
  * @author AlienTornadosaurusHex
  * @notice A contract which enumerates Tornado Cash pool instances, and also stores essential data regarding
  * them.
- * @dev This is contract will help us layout storage properly for a proxy upgrade for the impl
+ * @dev This contract will help us layout storage properly for a proxy upgrade for the impl
  * InstanceRegistry.
  */
 contract InstanceRegistryLegacyStorage {
-    /* From first contract */
+    /* From first contract, just so right uint type is chosen */
     enum LegacyStatePlaceholder {
         DISABLED,
         ENABLED
     }
 
-    /* From first contract */
+    /* From first contract, just if necessary to be able to properly unpack and determine value storage
+    addresses and offsets */
     struct LegacyInstanceStructPlaceholder {
         bool deprecatedIsERC20;
         address deprecatedToken;
@@ -42,22 +44,25 @@ contract InstanceRegistryLegacyStorage {
         uint32 deprecatedProtocolFeePercentage;
     }
 
-    /* From Initializable.sol of first contract */
+    /* @dev From Initializable.sol of first contract */
     bool private _deprecatedInitialized;
 
-    /* From Initializable.sol of first contract */
+    /* @dev From Initializable.sol of first contract */
     bool private _deprecatedInitializing;
 
-    /* From first contract */
+    /* @dev From first contract */
     address private _deprecatedRouterAddress;
 
-    /* From first contract */
+    /* @dev From first contract */
     mapping(address => LegacyInstanceStructPlaceholder) private _deprecatedInstances;
 
-    /* From first contract */
+    /* @dev From first contract */
     ITornadoInstance[] private _deprecatedInstanceIds;
 }
 
+/**
+ * @dev This struct holds barebones information regarding an instance and its data location in storage.
+ */
 struct InstanceData {
     IERC20 token;
     uint80 index;
@@ -91,7 +96,9 @@ contract InstanceRegistry is InstanceRegistryLegacyStorage, EnsResolve, Initiali
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EVENTS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
-    event NewRouterRegistered(address newRouterAddress);
+    event RouterRegistered(address newRouterAddress);
+    event InstanceAdded(address indexed instance, uint80 dataIndex, bool isERC20);
+    event InstanceRemoved(address indexed instance);
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ LOGIC ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
@@ -120,9 +127,12 @@ contract InstanceRegistry is InstanceRegistryLegacyStorage, EnsResolve, Initiali
 
     function addInstance(ITornadoInstance _instance) public virtual onlyGovernance {
         bool isEnabled = instanceData[_instance].isEnabled;
+
+        require(!isEnabled, "InstanceRegistry: can't add the same instance.");
+
         bool isERC20 = false;
 
-        IERC20 token;
+        IERC20 token = IERC20(address(0));
 
         // ETH instances do not know of a `token()` call
         try _instance.token() returns (address _tokenAddress) {
@@ -132,8 +142,8 @@ contract InstanceRegistry is InstanceRegistryLegacyStorage, EnsResolve, Initiali
             /* It's an ETH instance, do nothing */
         }
 
-        require(!isEnabled, "InstanceRegistry: can't add the same instance.");
+        // If it is ERC20 then make the router give an approval for the Tornado instance to allow the token
-
+        // amount... if it hasn't already done so
         if (isERC20) {
             uint256 routerAllowanceForInstance = token.allowance(address(router), address(_instance));
 
@@ -142,20 +152,33 @@ contract InstanceRegistry is InstanceRegistryLegacyStorage, EnsResolve, Initiali
             }
         }
 
+        // Add it to the enumerable
         instances.push(_instance);
 
-        instanceData[_instance] = InstanceData({
+        uint64 instanceIndex = uint64(instances.length - 1);
-            token: token,
+
-            index: uint64(instances.length - 1),
+        // Set data
-            isERC20: token != IERC20(address(0)), // TODO: Is this true?
+        instanceData[_instance] =
-            isEnabled: isEnabled
+            InstanceData({ token: token, index: instanceIndex, isERC20: isERC20, isEnabled: isEnabled });
-        });
+
+        // Log
+        emit InstanceAdded(address(_instance), instanceIndex, isERC20);
     }
 
+    /**
+     * @notice Remove an instance, only callable by Governance.
+     * @dev The modifier is in the internal call.
+     * @param _instanceIndex The index of the instance to remove.
+     */
     function removeInstanceByIndex(uint256 _instanceIndex) public virtual {
         _removeInstanceByAddress(address(instances[_instanceIndex]));
     }
 
+    /**
+     * @notice Remove an instance, only callable by Governance.
+     * @dev The modifier is in the internal call.
+     * @param _instanceAddress The adress of the instance to remove.
+     */
     function removeInstanceByAddress(address _instanceAddress) public virtual {
         _removeInstanceByAddress(_instanceAddress);
     }
@@ -164,6 +187,8 @@ contract InstanceRegistry is InstanceRegistryLegacyStorage, EnsResolve, Initiali
         ITornadoInstance instance = ITornadoInstance(_instanceAddress);
         InstanceData memory data = instanceData[instance];
 
+        // Kill the allowance of the router first (arbitrary order)
+
         if (data.isERC20) {
             uint256 routerAllowanceForInstance = data.token.allowance(address(router), _instanceAddress);
 
@@ -172,17 +197,34 @@ contract InstanceRegistry is InstanceRegistryLegacyStorage, EnsResolve, Initiali
             }
         }
 
-        instances[data.index] = instances[instances.length - 1];
+        // We need to revert all changes, meaning modify position of last instance and change index in data
+
+        uint64 lastInstanceIndex = uint64(instances.length - 1);
+
+        ITornadoInstance lastInstance = instances[lastInstanceIndex];
+
+        // Remove & swap
+
+        instances[data.index] = lastInstance;
+
+        instanceData[lastInstance].index = data.index;
+
         instances.pop();
 
+        // Delete for removed instance data
+
         delete instanceData[instance];
+
+        // Log
+
+        emit InstanceRemoved(_instanceAddress);
     }
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SETTERS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
     function setTornadoRouter(address _newRouterAddress) external onlyGovernance {
         router = TornadoRouter(_newRouterAddress);
-        emit NewRouterRegistered(_newRouterAddress);
+        emit RouterRegistered(_newRouterAddress);
     }
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GETTERS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
@@ -211,6 +253,15 @@ contract InstanceRegistry is InstanceRegistryLegacyStorage, EnsResolve, Initiali
         }
     }
 
+    function getInstanceData(ITornadoInstance _instance)
+        public
+        view
+        virtual
+        returns (InstanceData memory data)
+    {
+        return instanceData[_instance];
+    }
+
     function getInstanceToken(ITornadoInstance _instance) public view virtual returns (IERC20) {
         return instanceData[_instance].token;
     }
@@ -218,4 +269,37 @@ contract InstanceRegistry is InstanceRegistryLegacyStorage, EnsResolve, Initiali
     function getInstanceIndex(ITornadoInstance _instance) public view virtual returns (uint80) {
         return instanceData[_instance].index;
     }
+
+    function isRegisteredInstance(address _instanceAddress) public view virtual returns (bool) {
+        return isEnabledInstance(_instanceAddress);
+    }
+
+    function isEnabledInstance(address _instanceAddress) public view virtual returns (bool) {
+        return instanceData[ITornadoInstance(_instanceAddress)].isEnabled;
+    }
+
+    /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ENS GETTERS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+    function getInstanceByENSName(string memory _instanceENSName)
+        public
+        view
+        virtual
+        returns (ITornadoInstance)
+    {
+        (, bytes32 node) = NameEncoder.dnsEncodeName(_instanceENSName);
+        return ITornadoInstance(resolve(node));
+    }
+
+    function isRegisteredInstanceByENSName(string memory _instanceENSName)
+        public
+        view
+        virtual
+        returns (bool)
+    {
+        return isEnabledInstanceByENSName(_instanceENSName);
+    }
+
+    function isEnabledInstanceByENSName(string memory _instanceENSName) public view virtual returns (bool) {
+        return isEnabledInstance(address(getInstanceByENSName(_instanceENSName)));
+    }
 }

src/v2/TornadoRouter.sol

@@ -19,15 +19,24 @@ import { ITornadoInstance } from "tornado-anonymity-mining/contracts/interfaces/
 import { RelayerRegistry } from "../v1/RelayerRegistry.sol";
 import { InstanceRegistry, InstanceData } from "./InstanceRegistry.sol";
 
+/**
+ * @title TornadoRouter
+ * @author AlienTornadosaurusHex
+ * @notice This contracts is a router for all Tornado Cash deposits and withdrawals
+ * @dev This is an improved version of the TornadoRouter with a modified design from the original contract.
+ */
 contract TornadoRouter is Initializable {
     using SafeERC20 for IERC20;
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ VARIABLES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
+    /* @dev The address of the Governance proxy */
     address public immutable governanceProxyAddress;
 
+    /* @dev The instance registry */
     InstanceRegistry public instanceRegistry;
 
+    /* @dev The relayer registry */
     RelayerRegistry public relayerRegistry;
 
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EVENTS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
@@ -50,7 +59,7 @@ contract TornadoRouter is Initializable {
         _;
     }
 
-    function initalize(address _instanceRegistryAddress, address _relayerRegistryAddress)
+    function initialize(address _instanceRegistryAddress, address _relayerRegistryAddress)
         external
         onlyGovernance
         initializer
@@ -112,12 +121,12 @@ contract TornadoRouter is Initializable {
         require(_to != address(0), "TORN: can not send to zero address");
 
         if (_token == IERC20(0)) {
-            // for Ether
+            // For Ether
             uint256 totalBalance = address(this).balance;
             uint256 balance = Math.min(totalBalance, _amount);
             _to.transfer(balance);
         } else {
-            // any other erc20
+            // For any other ERC20
             uint256 totalBalance = _token.balanceOf(address(this));
             uint256 balance = Math.min(totalBalance, _amount);
             require(balance > 0, "TORN: trying to send 0 balance");
@@ -134,6 +143,14 @@ contract TornadoRouter is Initializable {
         _token.safeApprove(_spender, _amount);
     }
 
+    function setInstanceRegistry(address _newInstanceRegistryProxyAddress) external onlyGovernance {
+        instanceRegistry = InstanceRegistry(_newInstanceRegistryProxyAddress);
+    }
+
+    function setRelayerRegistry(address _newRelayerRegistryProxyAddress) external onlyGovernance {
+        relayerRegistry = RelayerRegistry(_newRelayerRegistryProxyAddress);
+    }
+
     /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GETTERS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
     function version() public pure virtual returns (string memory) {

src/v2/UniswapV3FeeOracle.sol

@@ -6,12 +6,160 @@ pragma experimental ABIEncoderV2;
 // OZ imports
 
 import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+// Uniswap imports
+
+import { IUniswapV3Factory } from "@uniswap/v3-core/contracts/interfaces/IUniswapV3Factory.sol";
+import { IUniswapV3PoolState } from "@uniswap/v3-core/contracts/interfaces/pool/IUniswapV3PoolState.sol";
+
+// Tornado imports
+
+import { ITornadoInstance } from "tornado-anonymity-mining/contracts/interfaces/ITornadoInstance.sol";
 
 // Local imports
 
-import { UniswapV3OracleHelper } from "./libraries/UniswapV3OracleHelper.sol";
 import { IFeeOracle } from "./interfaces/IFeeOracle.sol";
 
-contract UniswapV3FeeOracle is IFeeOracle {
+import { UniswapV3OracleHelper } from "./libraries/UniswapV3OracleHelper.sol";
-    function getFee() public view virtual override returns (uint160) { }
+
+import { InstanceData } from "./InstanceRegistry.sol";
+
+struct UniswapV3FeeData {
+    uint24 tornPoolFee;
+    uint24 tokenPoolFee;
+    uint32 timePeriod;
+}
+
+/**
+ * @title UniswapV3FeeOracle
+ * @author AlienTornadosaurusHex
+ * @notice A TORN fee oracle for any Uniswap V3 token pool.
+ */
+contract UniswapV3FeeOracle is IFeeOracle {
+    using SafeMath for uint256;
+
+    /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ VARIABLES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+    /* @dev The Governance Proxy address */
+    address public immutable governanceProxyAddress;
+
+    /* @dev The Uniswap V3 Factory */
+    IUniswapV3Factory public immutable v3Factory;
+
+    /* @dev The global pool fee value which will always be used for TORN */
+    uint24 public globalTornUniswapPoolFee;
+
+    /* @dev The global time period value which will be used for all calculations */
+    uint32 public globalUniswapTimePeriod;
+
+    /* @dev The minimum observation cardinality required for a token */
+    uint32 public globalMinObservationCardinality;
+
+    /* @dev The feeData in which the above + token specific will be stored */
+    mapping(IERC20 => UniswapV3FeeData) public uniswapFeeData;
+
+    /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EVENTS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+    event UniswapPoolFeeUpdated(IERC20 token, uint24 newUniswapPoolFee);
+    event GlobalTornUniswapPoolFeeUpdated(uint24 newUniswapPoolFee);
+    event GlobalUniswapTimePeriodUpdated(uint32 newUniswapTimePeriod);
+    event GlobalMinObservationCardinalityUpdated(uint16 newMinObservationCardinality);
+
+    /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ LOGIC ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+    constructor(address _governanceProxyAddress, address _uniswapV3FactoryAddress) public {
+        governanceProxyAddress = _governanceProxyAddress;
+        v3Factory = IUniswapV3Factory(_uniswapV3FactoryAddress);
+    }
+
+    modifier onlyGovernance() {
+        require(msg.sender == governanceProxyAddress, "UniswapV3FeeOracle: onlyGovernance");
+        _;
+    }
+
+    function setGlobalTornUniswapPoolFee(uint24 _newGlobalTornUniswapPoolFee) public virtual onlyGovernance {
+        globalTornUniswapPoolFee = _newGlobalTornUniswapPoolFee;
+        emit GlobalTornUniswapPoolFeeUpdated(_newGlobalTornUniswapPoolFee);
+    }
+
+    function setGlobalUniswapTimePeriod(uint32 _newGlobalUniswapTimePeriod) public virtual onlyGovernance {
+        globalUniswapTimePeriod = _newGlobalUniswapTimePeriod;
+        emit GlobalUniswapTimePeriodUpdated(_newGlobalUniswapTimePeriod);
+    }
+
+    function setGlobalMinObservationCardinality(uint16 _newGlobalMinObservationCardinality)
+        public
+        virtual
+        onlyGovernance
+    {
+        globalMinObservationCardinality = _newGlobalMinObservationCardinality;
+        emit GlobalMinObservationCardinalityUpdated(_newGlobalMinObservationCardinality);
+    }
+
+    function setUniswapPoolFeeForToken(IERC20 _token, uint24 _tokenUniswapPoolFee)
+        public
+        virtual
+        onlyGovernance
+    {
+        uint24 _globalTornUniswapPoolFee = globalTornUniswapPoolFee;
+        uint32 _globalUniswapTimePeriod = globalUniswapTimePeriod;
+
+        require(_globalTornUniswapPoolFee != 0, "UniswapV3FeeOracle: torn pool fee not initialized");
+        require(_globalUniswapTimePeriod != 0, "UniswapV3FeeOracle: time period not initialized");
+
+        address poolAddress =
+            v3Factory.getPool(address(_token), UniswapV3OracleHelper.WETH, _tokenUniswapPoolFee);
+
+        require(poolAddress != address(0), "UniswapV3FeeOracle: pool for token and fee does not exist");
+
+        (,,,, uint16 observationCardinalityNext,,) = IUniswapV3PoolState(poolAddress).slot0();
+
+        require(
+            globalMinObservationCardinality <= observationCardinalityNext,
+            "UniswapV3FeeOracle: pool observation cardinality low"
+        );
+
+        uniswapFeeData[_token] = UniswapV3FeeData({
+            tornPoolFee: _globalTornUniswapPoolFee,
+            tokenPoolFee: _tokenUniswapPoolFee,
+            timePeriod: _globalUniswapTimePeriod
+        });
+
+        emit UniswapPoolFeeUpdated(_token, _tokenUniswapPoolFee);
+    }
+
+    function getFee(
+        IERC20 _torn,
+        ITornadoInstance _instance,
+        InstanceData memory _data,
+        uint64 _feePercent,
+        uint64 _feePercentDivisor
+    ) public view virtual override returns (uint160) {
+        // For safety, we won't allow calculating fees for disabled instances
+        require(_data.isEnabled, "UniswapV3FeeOracle: instance not enabled");
+
+        // If fee is 0 return
+        if (_feePercent == 0) return 0;
+
+        // If it's not an ERC20 it has to be ETH, use the WETH token
+        _data.token = _data.isERC20 ? _data.token : IERC20(UniswapV3OracleHelper.WETH);
+
+        // After we have decided our token get fee data for it
+        UniswapV3FeeData memory uniFeeData = uniswapFeeData[_data.token];
+
+        // Calc price ratio
+        uint256 tokenPriceRatio = UniswapV3OracleHelper.getPriceRatioOfTokens(
+            [address(_torn), address(_data.token)],
+            [uniFeeData.tornPoolFee, uniFeeData.tokenPoolFee],
+            uniFeeData.timePeriod
+        );
+
+        // And now all according to legacy calculation
+        return uint160(
+            _instance.denomination().mul(UniswapV3OracleHelper.RATIO_DIVIDER).div(tokenPriceRatio).mul(
+                uint256(_feePercent)
+            ).div(_feePercentDivisor)
+        );
+    }
 }

src/v2/interfaces/IFeeOracle.sol

@@ -3,6 +3,24 @@
 pragma solidity ^0.6.12;
 pragma experimental ABIEncoderV2;
 
+// OZ Imports
+
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+// Tornado imports
+
+import { ITornadoInstance } from "tornado-anonymity-mining/contracts/interfaces/ITornadoInstance.sol";
+
+// Local imports
+
+import { InstanceData } from "../InstanceRegistry.sol";
+
 interface IFeeOracle {
-    function getFee() external view returns (uint160);
+    function getFee(
+        IERC20 _torn,
+        ITornadoInstance _instance,
+        InstanceData memory _data,
+        uint64 _feePercent,
+        uint64 _feePercentDivisor
+    ) external view returns (uint160);
 }

src/v2/libraries/BytesUtils.sol

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.6.12;
+pragma experimental ABIEncoderV2;
+
+library BytesUtils {
+    /*
+     * @dev Returns the keccak-256 hash of a byte range.
+     * @param self The byte string to hash.
+     * @param offset The position to start hashing at.
+     * @param len The number of bytes to hash.
+     * @return The hash of the byte range.
+     */
+    function keccak(bytes memory self, uint256 offset, uint256 len) internal pure returns (bytes32 ret) {
+        require(offset + len <= self.length);
+        assembly {
+            ret := keccak256(add(add(self, 32), offset), len)
+        }
+    }
+
+    /**
+     * @dev Returns the ENS namehash of a DNS-encoded name.
+     * @param self The DNS-encoded name to hash.
+     * @param offset The offset at which to start hashing.
+     * @return The namehash of the name.
+     */
+    function namehash(bytes memory self, uint256 offset) internal pure returns (bytes32) {
+        (bytes32 labelhash, uint256 newOffset) = readLabel(self, offset);
+        if (labelhash == bytes32(0)) {
+            require(offset == self.length - 1, "namehash: Junk at end of name");
+            return bytes32(0);
+        }
+        return keccak256(abi.encodePacked(namehash(self, newOffset), labelhash));
+    }
+
+    /**
+     * @dev Returns the keccak-256 hash of a DNS-encoded label, and the offset to the start of the next label.
+     * @param self The byte string to read a label from.
+     * @param idx The index to read a label at.
+     * @return labelhash The hash of the label at the specified index, or 0 if it is the last label.
+     * @return newIdx The index of the start of the next label.
+     */
+    function readLabel(bytes memory self, uint256 idx)
+        internal
+        pure
+        returns (bytes32 labelhash, uint256 newIdx)
+    {
+        require(idx < self.length, "readLabel: Index out of bounds");
+        uint256 len = uint256(uint8(self[idx]));
+        if (len > 0) {
+            labelhash = keccak(self, idx + 1, len);
+        } else {
+            labelhash = bytes32(0);
+        }
+        newIdx = idx + len + 1;
+    }
+}

src/v2/libraries/NameEncoder.sol

@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.6.12;
+pragma experimental ABIEncoderV2;
+
+import { BytesUtils } from "./BytesUtils.sol";
+
+library NameEncoder {
+    using BytesUtils for bytes;
+
+    function dnsEncodeName(string memory name) internal pure returns (bytes memory dnsName, bytes32 node) {
+        uint8 labelLength = 0;
+        bytes memory bytesName = bytes(name);
+        uint256 length = bytesName.length;
+        dnsName = new bytes(length + 2);
+        node = 0;
+        if (length == 0) {
+            dnsName[0] = 0;
+            return (dnsName, node);
+        }
+
+        for (uint256 i = length - 1; i >= 0; i--) {
+            if (bytesName[i] == ".") {
+                dnsName[i + 1] = bytes1(labelLength);
+                node = keccak256(abi.encodePacked(node, bytesName.keccak(i + 1, labelLength)));
+                labelLength = 0;
+            } else {
+                labelLength += 1;
+                dnsName[i + 1] = bytesName[i];
+            }
+            if (i == 0) {
+                break;
+            }
+        }
+
+        node = keccak256(abi.encodePacked(node, bytesName.keccak(0, labelLength)));
+
+        dnsName[0] = bytes1(labelLength);
+        return (dnsName, node);
+    }
+}