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Finalize token transfer fee billing (#187)
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* make minFee and maxFee per token

* nit
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@matYang
matYang authored Oct 6, 2023
1 parent 8e9719d commit 68ebce8
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Showing 11 changed files with 260 additions and 263 deletions.
188 changes: 94 additions & 94 deletions contracts/gas-snapshots/ccip.gas-snapshot
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62 changes: 32 additions & 30 deletions contracts/src/v0.8/ccip/onRamp/EVM2EVMOnRamp.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -93,8 +93,6 @@ contract EVM2EVMOnRamp is IEVM2AnyOnRamp, ILinkAvailable, AggregateRateLimiter,
/// @dev Struct to hold the execution fee configuration for a fee token
struct FeeTokenConfig {
uint32 networkFeeUSD; // ───────────╮ Flat network fee to charge for messages, multiples of 0.01 USD
uint32 minTokenTransferFeeUSD; // │ Minimum fee to charge for token transfers, multiples of 0.01 USD
uint32 maxTokenTransferFeeUSD; // │ Maximum fee to charge for token transfers, multiples of 0.01 USD
uint64 gasMultiplier; // │ Price multiplier for gas costs, 1e18 based so 11e17 = 10% extra cost.
uint64 premiumMultiplier; // │ Multiplier for fee-token-specific premiums
bool enabled; // ───────────────────╯ Whether this fee token is enabled
Expand All @@ -105,16 +103,16 @@ contract EVM2EVMOnRamp is IEVM2AnyOnRamp, ILinkAvailable, AggregateRateLimiter,
struct FeeTokenConfigArgs {
address token; // ──────────────────╮ Token address
uint32 networkFeeUSD; // │ Flat network fee to charge for messages, multiples of 0.01 USD
uint32 minTokenTransferFeeUSD; // │ Minimum fee to charge for token transfers, multiples of 0.01 USD
uint32 maxTokenTransferFeeUSD; //───╯ Maximum fee to charge for token transfers, multiples of 0.01 USD
uint64 gasMultiplier; // ───╮ Price multiplier for gas costs, 1e18 based so 11e17 = 10% extra cost
uint64 premiumMultiplier; // │ Multiplier for fee-token-specific premiums
uint64 gasMultiplier; // ───────────╯ Price multiplier for gas costs, 1e18 based so 11e17 = 10% extra cost
uint64 premiumMultiplier; // ───────╮ Multiplier for fee-token-specific premiums
bool enabled; // ───────────────────╯ Whether this fee token is enabled
}

/// @dev Struct to hold the transfer fee configuration for token transfers
struct TokenTransferFeeConfig {
uint16 ratio; // ───────────────────╮ Ratio of token transfer value to charge as fee, multiples of 0.1bps, or 1e-5
uint32 minFeeUSD; // ───────────────╮ Minimum fee to charge per token transfer, multiples of 0.01 USD
uint32 maxFeeUSD; // │ Maximum fee to charge per token transfer, multiples of 0.01 USD
uint16 ratio; // │ Ratio of token transfer value to charge as fee, multiples of 0.1bps, or 1e-5
uint32 destGasOverhead; // │ Gas charged to execute the token transfer on the destination chain
uint32 destBytesOverhead; // ───────╯ Extra data availability bytes on top of fixed transfer data, e.g. USDC source token data and offchain data
}
Expand All @@ -123,8 +121,10 @@ contract EVM2EVMOnRamp is IEVM2AnyOnRamp, ILinkAvailable, AggregateRateLimiter,
/// token included so that an array of these can be passed in to setTokenTransferFeeConfig
struct TokenTransferFeeConfigArgs {
address token; // ──────────────────╮ Token address
uint16 ratio; // │ Ratio of token transfer value to charge as fee, multiples of 0.1bps, or 1e-5
uint32 destGasOverhead; // │ Gas charged to execute the token transfer on the destination chain
uint32 minFeeUSD; // │ Minimum fee to charge per token transfer, multiples of 0.01 USD
uint32 maxFeeUSD; // │ Maximum fee to charge per token transfer, multiples of 0.01 USD
uint16 ratio; // ───────────────────╯ Ratio of token transfer value to charge as fee, multiples of 0.1bps, or 1e-5
uint32 destGasOverhead; // ─────────╮ Gas charged to execute the token transfer on the destination chain
uint32 destBytesOverhead; // ───────╯ Extra data availability bytes on top of fixed transfer data, e.g. USDC source token data and offchain data
}

Expand Down Expand Up @@ -495,17 +495,17 @@ contract EVM2EVMOnRamp is IEVM2AnyOnRamp, ILinkAvailable, AggregateRateLimiter,
uint112 executionGasPrice = uint112(packedGasPrice);

// Calculate premiumFee in USD with 18 decimals precision.
// If there are token transfers, premiumFee is calculated from token transfer fees.
// If there are no token transfers, we charge a flat network fee.
// If message-only and no token transfers, a flat network fee is charged.
// If there are token transfers, premiumFee is calculated from token transfer fee.
// If there are both token transfers and message, premiumFee is only calculated from token transfer fee.
uint256 premiumFeeUSD = 0;
uint32 tokenTransferGas = 0;
uint32 tokenTransferBytesOverhead = 0;
if (message.tokenAmounts.length > 0) {
(premiumFeeUSD, tokenTransferGas, tokenTransferBytesOverhead) = _getTokenTransferCost(
message.feeToken,
feeTokenPrice,
message.tokenAmounts,
feeTokenConfig
message.tokenAmounts
);
} else {
// Convert USD values with 2 decimals to 18 decimals.
Expand Down Expand Up @@ -573,22 +573,21 @@ contract EVM2EVMOnRamp is IEVM2AnyOnRamp, ILinkAvailable, AggregateRateLimiter,

/// @notice Returns the token transfer fee.
/// A basis point fee is calculated from the USD value of each token transfer.
/// Sum of basis point fees is confined within range [minTokenTransferFeeUSD, maxTokenTransferFeeUSD].
/// For each individual transfer, this fee is between [minFeeUSD, maxFeeUSD].
/// Total transfer fee is the sum of each individual token transfer fee.
/// @dev Assumes that tokenAmounts are validated to be listed tokens elsewhere.
/// @dev Splitting one token transfer into multiple transfers is discouraged,
/// as it will result in a transferFee equal or greater than the same amount aggregated/de-duped.
/// @param feeToken address of the feeToken.
/// @param feeTokenPrice price of feeToken in USD with 18 decimals.
/// @param tokenAmounts token transfers in the message.
/// @param feeTokenConfig configuration struct of fee token.
/// @return tokenTransferFeeUSD total token transfer bps fee in USD with 36 decimals.
/// @return tokenTransferGas total execution gas of the token transfers.
/// @return tokenTransferBytesOverhead additional token transfer data passed to destination, e.g. USDC attestation.
function _getTokenTransferCost(
address feeToken,
uint224 feeTokenPrice,
Client.EVMTokenAmount[] calldata tokenAmounts,
FeeTokenConfig memory feeTokenConfig
Client.EVMTokenAmount[] calldata tokenAmounts
) internal view returns (uint256 tokenTransferFeeUSD, uint32 tokenTransferGas, uint32 tokenTransferBytesOverhead) {
uint256 numberOfTokens = tokenAmounts.length;

Expand All @@ -615,21 +614,24 @@ contract EVM2EVMOnRamp is IEVM2AnyOnRamp, ILinkAvailable, AggregateRateLimiter,
bpsFeeUSD = (tokenPrice._calcUSDValueFromTokenAmount(tokenAmount.amount) * transferFeeConfig.ratio) / 1e5;
}

tokenTransferFeeUSD += bpsFeeUSD;
tokenTransferGas += transferFeeConfig.destGasOverhead;
tokenTransferBytesOverhead += transferFeeConfig.destBytesOverhead;
}

// Convert USD values with 2 decimals to 18 decimals.
// Sum of bps fees should be kept within range of [minTokenTransferFeeUSD, maxTokenTransferFeeUSD].
uint256 minTransferFeeUSD = uint256(feeTokenConfig.minTokenTransferFeeUSD) * 1e16;
if (tokenTransferFeeUSD < minTransferFeeUSD) {
return (minTransferFeeUSD, tokenTransferGas, tokenTransferBytesOverhead);
}
// Bps fees should be kept within range of [minFeeUSD, maxFeeUSD].
// Convert USD values with 2 decimals to 18 decimals.
uint256 minFeeUSD = uint256(transferFeeConfig.minFeeUSD) * 1e16;
if (bpsFeeUSD < minFeeUSD) {
tokenTransferFeeUSD += minFeeUSD;
continue;
}

uint256 maxTransferFeeUSD = uint256(feeTokenConfig.maxTokenTransferFeeUSD) * 1e16;
if (tokenTransferFeeUSD > maxTransferFeeUSD) {
return (maxTransferFeeUSD, tokenTransferGas, tokenTransferBytesOverhead);
uint256 maxFeeUSD = uint256(transferFeeConfig.maxFeeUSD) * 1e16;
if (bpsFeeUSD > maxFeeUSD) {
tokenTransferFeeUSD += maxFeeUSD;
continue;
}

tokenTransferFeeUSD += bpsFeeUSD;
}

return (tokenTransferFeeUSD, tokenTransferGas, tokenTransferBytesOverhead);
Expand All @@ -656,8 +658,6 @@ contract EVM2EVMOnRamp is IEVM2AnyOnRamp, ILinkAvailable, AggregateRateLimiter,

s_feeTokenConfig[configArg.token] = FeeTokenConfig({
networkFeeUSD: configArg.networkFeeUSD,
minTokenTransferFeeUSD: configArg.minTokenTransferFeeUSD,
maxTokenTransferFeeUSD: configArg.maxTokenTransferFeeUSD,
gasMultiplier: configArg.gasMultiplier,
premiumMultiplier: configArg.premiumMultiplier,
enabled: configArg.enabled
Expand Down Expand Up @@ -687,6 +687,8 @@ contract EVM2EVMOnRamp is IEVM2AnyOnRamp, ILinkAvailable, AggregateRateLimiter,
TokenTransferFeeConfigArgs memory configArg = tokenTransferFeeConfigArgs[i];

s_tokenTransferFeeConfig[configArg.token] = TokenTransferFeeConfig({
minFeeUSD: configArg.minFeeUSD,
maxFeeUSD: configArg.maxFeeUSD,
ratio: configArg.ratio,
destGasOverhead: configArg.destGasOverhead,
destBytesOverhead: configArg.destBytesOverhead
Expand Down
5 changes: 2 additions & 3 deletions contracts/src/v0.8/ccip/test/helpers/EVM2EVMOnRampHelper.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -43,9 +43,8 @@ contract EVM2EVMOnRampHelper is EVM2EVMOnRamp, IgnoreContractSize {
function getTokenTransferCost(
address feeToken,
uint224 feeTokenPrice,
Client.EVMTokenAmount[] calldata tokenAmounts,
FeeTokenConfig memory feeTokenConfig
Client.EVMTokenAmount[] calldata tokenAmounts
) external view returns (uint256, uint32, uint32) {
return _getTokenTransferCost(feeToken, feeTokenPrice, tokenAmounts, feeTokenConfig);
return _getTokenTransferCost(feeToken, feeTokenPrice, tokenAmounts);
}
}
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