core: Fixed gas price (#205)

* core/vm: update abi
* core/vm: add MinGasPrice to gov
* params: Add MinGasPrice to Config
* dex: SuggestPrice from Governance
* test: add minGasPrice to genesis.json
* core: check underpriced tx
* dex: verify with gas price

3 files changed, 45 insertions, 1 deletions

diff --git a/core/vm/oracle_contract_abi.go b/core/vm/oracle_contract_abi.go
index fde973203..ff4a94b29 100644
--- a/core/vm/oracle_contract_abi.go
+++ b/core/vm/oracle_contract_abi.go
@@ -566,6 +566,20 @@ const GovernanceABIJSON = `
   {
     "constant": true,
     "inputs": [],
+    "name": "minGasPrice",
+    "outputs": [
+      {
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": true,
+    "inputs": [],
     "name": "lockupPeriod",
     "outputs": [
       {
@@ -855,6 +869,10 @@ const GovernanceABIJSON = `
       {
         "name": "FineValues",
         "type": "uint256[]"
+      },
+      {
+        "name": "MinGasPrice",
+        "type": "uint256"
       }
     ],
     "name": "updateConfiguration",
diff --git a/core/vm/oracle_contracts.go b/core/vm/oracle_contracts.go
index 1eeb57a5a..826e0396c 100644
--- a/core/vm/oracle_contracts.go
+++ b/core/vm/oracle_contracts.go
@@ -83,6 +83,7 @@ const (
 	fineValuesLoc
 	finedRecordsLoc
 	dkgResetCountLoc
+	minGasPriceLoc
 )
 
 func publicKeyToNodeID(pkBytes []byte) (Bytes32, error) {
@@ -894,6 +895,11 @@ func (s *GovernanceStateHelper) IncDKGResetCount(round *big.Int) {
 	s.setStateBigInt(loc, new(big.Int).Add(count, big.NewInt(1)))
 }
 
+// uint256 public minGasPrice;
+func (s *GovernanceStateHelper) MinGasPrice() *big.Int {
+	return s.getStateBigInt(big.NewInt(minGasPriceLoc))
+}
+
 // Stake is a helper function for creating genesis state.
 func (s *GovernanceStateHelper) Stake(
 	addr common.Address, publicKey []byte, staked *big.Int,
@@ -948,6 +954,7 @@ func (s *GovernanceStateHelper) Configuration() *params.DexconConfig {
 		RoundLength:       s.getStateBigInt(big.NewInt(roundLengthLoc)).Uint64(),
 		MinBlockInterval:  s.getStateBigInt(big.NewInt(minBlockIntervalLoc)).Uint64(),
 		FineValues:        s.FineValues(),
+		MinGasPrice:       s.getStateBigInt(big.NewInt(minGasPriceLoc)),
 	}
 }
 
@@ -966,6 +973,7 @@ func (s *GovernanceStateHelper) UpdateConfiguration(cfg *params.DexconConfig) {
 	s.setStateBigInt(big.NewInt(roundLengthLoc), big.NewInt(int64(cfg.RoundLength)))
 	s.setStateBigInt(big.NewInt(minBlockIntervalLoc), big.NewInt(int64(cfg.MinBlockInterval)))
 	s.SetFineValues(cfg.FineValues)
+	s.setStateBigInt(big.NewInt(minGasPriceLoc), cfg.MinGasPrice)
 }
 
 type rawConfigStruct struct {
@@ -979,6 +987,7 @@ type rawConfigStruct struct {
 	RoundLength      *big.Int
 	MinBlockInterval *big.Int
 	FineValues       []*big.Int
+	MinGasPrice      *big.Int
 }
 
 // UpdateConfigurationRaw updates system configuration.
@@ -993,6 +1002,7 @@ func (s *GovernanceStateHelper) UpdateConfigurationRaw(cfg *rawConfigStruct) {
 	s.setStateBigInt(big.NewInt(roundLengthLoc), cfg.RoundLength)
 	s.setStateBigInt(big.NewInt(minBlockIntervalLoc), cfg.MinBlockInterval)
 	s.SetFineValues(cfg.FineValues)
+	s.setStateBigInt(big.NewInt(minGasPriceLoc), cfg.MinGasPrice)
 }
 
 // event ConfigurationChanged();
@@ -2227,6 +2237,12 @@ func (g *GovernanceContract) Run(evm *EVM, input []byte, contract *Contract) (re
 			return nil, errExecutionReverted
 		}
 		return res, nil
+	case "minGasPrice":
+		res, err := method.Outputs.Pack(g.state.MinGasPrice())
+		if err != nil {
+			return nil, errExecutionReverted
+		}
+		return res, nil
 	case "miningVelocity":
 		res, err := method.Outputs.Pack(g.state.MiningVelocity())
 		if err != nil {
diff --git a/core/vm/oracle_contracts_test.go b/core/vm/oracle_contracts_test.go
index dd17dddea..4980d4b77 100644
--- a/core/vm/oracle_contracts_test.go
+++ b/core/vm/oracle_contracts_test.go
@@ -654,7 +654,8 @@ func (g *OracleContractsTestSuite) TestUpdateConfiguration() {
 		big.NewInt(4),
 		big.NewInt(600),
 		big.NewInt(900),
-		[]*big.Int{big.NewInt(1), big.NewInt(1), big.NewInt(1)})
+		[]*big.Int{big.NewInt(1), big.NewInt(1), big.NewInt(1)},
+		big.NewInt(2e9))
 	g.Require().NoError(err)
 
 	// Call with non-owner.
@@ -770,6 +771,15 @@ func (g *OracleContractsTestSuite) TestConfigurationReading() {
 	err = GovernanceABI.ABI.Unpack(&value, "minBlockInterval", res)
 	g.Require().NoError(err)
 	g.Require().Equal(g.config.MinBlockInterval, value.Uint64())
+
+	// MinGasPrice.
+	input, err = GovernanceABI.ABI.Pack("minGasPrice")
+	g.Require().NoError(err)
+	res, err = g.call(GovernanceContractAddress, addr, input, big.NewInt(0))
+	g.Require().NoError(err)
+	err = GovernanceABI.ABI.Unpack(&value, "minGasPrice", res)
+	g.Require().NoError(err)
+	g.Require().Equal(g.config.MinGasPrice, value)
 }
 
 func (g *OracleContractsTestSuite) TestReportForkVote() {