use frx/weth dual oracle for frxETH price

src/external/frax/IFrxEthWethDualOracle.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: BSD 3-Clause License
+pragma solidity ^0.8.24;
+
+interface IFrxEthWethDualOracle {
+
+    /// @notice The ```getCurveEmaEthPerFrxEth``` function gets the EMA price of frxEth in eth units
+    /// @dev normalized to match precision of oracle
+    /// @return _ethPerFrxEth
+     function getCurveEmaEthPerFrxEth() external view returns (uint256 _ethPerFrxEth);
+}

src/external/frax/IsfrxETH.sol

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: BSD 3-Clause License
+pragma solidity ^0.8.24;
+
+import {IERC4626} from "lib/openzeppelin-contracts/contracts/interfaces/IERC4626.sol";
+
+interface IsfrxETH is IERC4626 {
+    function pricePerShare() external view returns (uint256);
+}

src/ynEIGEN/LSDRateProvider.sol

@@ -7,6 +7,8 @@ import {IstETH} from "src/external/lido/IstETH.sol";
 import {IrETH} from "src/external/rocketpool/IrETH.sol";
 import {IswETH} from "src/external/swell/IswETH.sol";
 import {ImETHStaking} from "src/external/mantle/ImETHStaking.sol";
+import {IFrxEthWethDualOracle} from "src/external/frax/IFrxEthWethDualOracle.sol";
+import {IsfrxETH} from "src/external/frax/IsfrxETH.sol";
 
 contract LSDRateProvider {
 
@@ -22,6 +24,7 @@ contract LSDRateProvider {
 
     uint256 constant UNIT = 1e18;
     address constant FRAX_ASSET = 0xac3E018457B222d93114458476f3E3416Abbe38F; // sfrxETH
+    address constant FRX_ETH_WETH_DUAL_ORACLE = 0x350a9841956D8B0212EAdF5E14a449CA85FAE1C0; // FrxEthWethDualOracle
     address constant LIDO_ASSET = 0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0; // wstETH
     address constant RETH_ASSET = 0xae78736Cd615f374D3085123A210448E74Fc6393; // RETH
     address constant WOETH_ASSET = 0xDcEe70654261AF21C44c093C300eD3Bb97b78192;
@@ -47,10 +50,9 @@ contract LSDRateProvider {
 
         /*
             This contract uses the rate as provided the protocol that controls the asset.
-            This approach avoids issues with sourcing market prices that would cause asset value
-            fluctuation that depends on market price fluctuation
-            Known risks that require mitigation:
-            In case one of the LSDs depegs from its ETH price, users can still deposit to ynEigen, 
+            Known current risks:
+            In case one of the LSDs depegs from its ETH price and the oracles still report the undepegged price,
+            users can still deposit to ynEigen, 
             and receive the same amount of shares as though the underlying asset has not depegged yet,
             as the protocols below will report the same LSD/ETH price.
         */
@@ -59,7 +61,13 @@ contract LSDRateProvider {
             return IstETH(LIDO_UDERLYING).getPooledEthByShares(UNIT);
         }
         if (_asset == FRAX_ASSET) {
-            return IERC4626(FRAX_ASSET).totalAssets() * UNIT / IERC20(FRAX_ASSET).totalSupply();
+            /* Calculate the price per share of sfrxETH in terms of ETH using the Frax Oracle.
+               The Frax Oracle provides a time-weighted average price (TWAP) using a curve exponential moving average (EMA)
+               to smooth out the price fluctuations of ETH per sfrxETH. This helps in obtaining a stable conversion rate.
+            */
+
+            uint256 frxETHPriceInETH = IFrxEthWethDualOracle(FRX_ETH_WETH_DUAL_ORACLE).getCurveEmaEthPerFrxEth();
+            return IsfrxETH(FRAX_ASSET).pricePerShare() * frxETHPriceInETH / UNIT;
         }
         if (_asset == WOETH_ASSET) {
             return IERC4626(WOETH_ASSET).previewRedeem(UNIT);

test/integration/ynEIGEN/AssetRegistry.t.sol

@@ -13,6 +13,8 @@ import {IERC4626} from "lib/openzeppelin-contracts/contracts/interfaces/IERC4626
 import {IrETH} from "src/external/rocketpool/IrETH.sol";
 import { IwstETH } from "src/external/lido/IwstETH.sol";
 import {IstETH} from "src/external/lido/IstETH.sol";
+import {IFrxEthWethDualOracle} from "src/external/frax/IFrxEthWethDualOracle.sol";
+import {IsfrxETH} from "src/external/frax/IsfrxETH.sol";
 import {IAccessControl} from "lib/openzeppelin-contracts/contracts/access/IAccessControl.sol";
 
 import "forge-std/console.sol";
@@ -145,7 +147,8 @@ contract AssetRegistryTest is ynEigenIntegrationBaseTest {
         // End of the Selection
         IERC20 asset = IERC20(chainAddresses.lsd.SFRXETH_ADDRESS); // Using wstETH as the asset
         address FRAX_ASSET = chainAddresses.lsd.SFRXETH_ADDRESS;
-        uint256 realRate = IERC4626(FRAX_ASSET).totalAssets() * 1e18 / IERC20(FRAX_ASSET).totalSupply();
+        IFrxEthWethDualOracle FRX_ETH_WETH_DUAL_ORACLE = IFrxEthWethDualOracle(testAssetUtils.FRX_ETH_WETH_DUAL_ORACLE());
+        uint256 realRate = IsfrxETH(FRAX_ASSET).pricePerShare() * FRX_ETH_WETH_DUAL_ORACLE.getCurveEmaEthPerFrxEth() / 1e18;
         uint256 expectedConvertedAmount = amount * realRate / 1e18; // Calculating the expected converted amount based on the real rate
         uint256 convertedAmount = assetRegistry.convertToUnitOfAccount(asset, amount);
         assertEq(convertedAmount, expectedConvertedAmount, "Converted amount should match expected value based on real rate");

test/utils/TestAssetUtils.sol

@@ -22,9 +22,19 @@ contract TestAssetUtils is Test {
     ContractAddresses.ChainAddresses chainAddresses;
     ContractAddresses contractAddresses;
 
+    address public FRX_ETH_WETH_DUAL_ORACLE;
+
+
     constructor() {
         contractAddresses = new ContractAddresses();
         chainAddresses = contractAddresses.getChainAddresses(block.chainid);
+
+        if (block.chainid == 1) {
+            FRX_ETH_WETH_DUAL_ORACLE = 0x350a9841956D8B0212EAdF5E14a449CA85FAE1C0;
+        } else if (block.chainid == 17000) {
+            // UNAVAILABLE
+            FRX_ETH_WETH_DUAL_ORACLE = address(0x0);
+        }
     }
 
     function get_Asset(address asset, address receiver, uint256 amount) public returns (uint256 balance) {