Compute ETX fee multiplier according to ETX distance

ETXs emitted from a chain must contain a BaseFee that scales according to the distance the ETX travels, to account for BaseFee differences between chains. Additionally, emitted ETXs must contain sufficient tip to encourage speedy processing at the destination, since ETXs are costly to sit in pending status.
imdatdalga · Jul 18, 2023 · 2963248 · 2963248
1 parent 2013913
commit 2963248
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Showing 4 changed files with 20 additions and 8 deletions.
diff --git a/core/vm/contracts.go b/core/vm/contracts.go
@@ -283,6 +283,7 @@ type bigModExp struct {
 var (
 	big0      = big.NewInt(0)
 	big1      = big.NewInt(1)
+	big2      = big.NewInt(2)
 	big3      = big.NewInt(3)
 	big4      = big.NewInt(4)
 	big7      = big.NewInt(7)

diff --git a/core/vm/evm.go b/core/vm/evm.go
@@ -530,7 +530,7 @@ func (evm *EVM) CreateETX(toAddr common.Address, fromAddr common.Address, etxGas
 		return []byte{}, 0, fmt.Errorf("CreateETX error: %s", err.Error())
 	}
 
-	if err := evm.ValidateETXGasPriceAndTip(fromAddr, etxGasPrice, etxGasTip); err != nil {
+	if err := evm.ValidateETXGasPriceAndTip(fromAddr, toAddr, etxGasPrice, etxGasTip); err != nil {
 		return []byte{}, 0, err
 	}
 
@@ -559,8 +559,19 @@ func (evm *EVM) CreateETX(toAddr common.Address, fromAddr common.Address, etxGas
 	return []byte{}, gas - params.ETXGas, nil
 }
 
+// Emitted ETXs must include some multiple of BaseFee as miner tip, to
+// encourage processing at the destination.
+func calcEtxFeeMultiplier(fromAddr, toAddr common.Address) *big.Int {
+	confirmationCtx := fromAddr.Location().CommonDom(*toAddr.Location()).Context()
+	multiplier := big.NewInt(common.NumZonesInRegion)
+	if confirmationCtx == common.PRIME_CTX {
+		multiplier = big.NewInt(0).Mul(multiplier, big.NewInt(common.NumRegionsInPrime))
+	}
+	return multiplier
+}
+
 // Validate ETX gas price and tip
-func (evm *EVM) ValidateETXGasPriceAndTip(fromAddr common.Address, etxGasPrice *big.Int, etxGasTip *big.Int) error {
+func (evm *EVM) ValidateETXGasPriceAndTip(fromAddr, toAddr common.Address, etxGasPrice *big.Int, etxGasTip *big.Int) error {
 	if l := etxGasPrice.BitLen(); l > 256 {
 		return fmt.Errorf("max fee per gas higher than 2^256-1: address %v, etxGasPrice bit length: %d",
 			fromAddr, l)
@@ -575,15 +586,16 @@ func (evm *EVM) ValidateETXGasPriceAndTip(fromAddr common.Address, etxGasPrice *
 	}
 	// This will panic if baseFee is nil, but basefee presence is verified
 	// as part of header validation.
-	mulBaseFee := new(big.Int).Mul(evm.Context.BaseFee, big.NewInt(int64(params.ETXBaseFeeMultiplier)))
+	feeMul := calcEtxFeeMultiplier(fromAddr, toAddr)
+	mulBaseFee := new(big.Int).Mul(evm.Context.BaseFee, feeMul)
 	if etxGasPrice.Cmp(mulBaseFee) < 0 {
 		return fmt.Errorf("etx max fee per gas less than %dx block base fee: address %v, maxFeePerGas: %s baseFee: %s",
-			params.ETXBaseFeeMultiplier, fromAddr, etxGasPrice, evm.Context.BaseFee)
+			feeMul, fromAddr, etxGasPrice, evm.Context.BaseFee)
 	}
-	mulTip := new(big.Int).Mul(evm.TXGasTip, big.NewInt(int64(params.ETXBaseFeeMultiplier)))
+	mulTip := new(big.Int).Mul(evm.TXGasTip, feeMul)
 	if etxGasTip.Cmp(mulTip) < 0 {
 		return fmt.Errorf("etx miner tip cap less than %dx tx miner tip cap: address %v, etxGasTip: %s txGasTip: %s",
-			params.ETXBaseFeeMultiplier, fromAddr, etxGasTip, evm.TXGasTip)
+			feeMul, fromAddr, etxGasTip, evm.TXGasTip)
 	}
 	return nil
 }

diff --git a/core/vm/instructions.go b/core/vm/instructions.go
@@ -862,7 +862,7 @@ func opETX(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte
 		return nil, nil
 	}
 	// Fail if ETX gas price or tip are not valid
-	if err := interpreter.evm.ValidateETXGasPriceAndTip(scope.Contract.Caller(), gasFeeCap.ToBig(), gasTipCap.ToBig()); err != nil {
+	if err := interpreter.evm.ValidateETXGasPriceAndTip(scope.Contract.Caller(), toAddr, gasFeeCap.ToBig(), gasTipCap.ToBig()); err != nil {
 		temp.Clear()
 		stack.push(&temp)
 		fmt.Printf("%x opETX error: %s\n", scope.Contract.self.Address(), err.Error())

diff --git a/params/protocol_params.go b/params/protocol_params.go
@@ -35,7 +35,6 @@ const (
 	LogDataGas            uint64 = 8     // Per byte in a LOG* operation's data.
 	CallStipend           uint64 = 2300  // Free gas given at beginning of call.
 	ETXGas                uint64 = 21000 // Per ETX generated by opETX or normal cross-chain transfer.
-	ETXBaseFeeMultiplier  uint64 = 2     // Multiplier for the base fee of ETXs.
 
 	Sha3Gas     uint64 = 30 // Once per SHA3 operation.
 	Sha3WordGas uint64 = 6  // Once per word of the SHA3 operation's data.