dex: implement recovery mechanism (#258)

* dex: implement recovery mechanism

The DEXON recovery protocol allows us to use the Ethereum blockchain as a
fallback consensus chain to coordinate recovery.

* fix

2 files changed, 39 insertions, 10 deletions

diff --git a/params/config.go b/params/config.go
index 21f0f29e1..aa37ec1c4 100644
--- a/params/config.go
+++ b/params/config.go
@@ -68,6 +68,11 @@ var (
 				new(big.Int).Mul(big.NewInt(1e18), big.NewInt(1e5)),
 			},
 		},
+		Recovery: &RecoveryConfig{
+			Contract:     common.HexToAddress("0xcb4bb8ae26b2ebe5a1e2e8d5236020f33ffb2294"),
+			Timeout:      120,
+			Confirmation: 5,
+		},
 	}
 
 	// MainnetTrustedCheckpoint contains the light client trusted checkpoint for the main network.
@@ -114,6 +119,11 @@ var (
 				new(big.Int).Mul(big.NewInt(1e18), big.NewInt(1e5)),
 			},
 		},
+		Recovery: &RecoveryConfig{
+			Contract:     common.HexToAddress("0x4ebe3d13ab18b30d815711b7a33ef1226777b66d"),
+			Timeout:      120,
+			Confirmation: 5,
+		},
 	}
 
 	// TaipeiChainConfig contains the chain parameters to run a node on the Taipei test network.
@@ -151,6 +161,11 @@ var (
 				new(big.Int).Mul(big.NewInt(1e18), big.NewInt(1e5)),
 			},
 		},
+		Recovery: &RecoveryConfig{
+			Contract:     common.HexToAddress("0xac86ab80ab27007801f36f6622fbe0a9432291a2"),
+			Timeout:      120,
+			Confirmation: 1,
+		},
 	}
 
 	// TestnetTrustedCheckpoint contains the light client trusted checkpoint for the Ropsten test network.
@@ -196,6 +211,11 @@ var (
 				new(big.Int).Mul(big.NewInt(1e18), big.NewInt(1e5)),
 			},
 		},
+		Recovery: &RecoveryConfig{
+			Contract:     common.HexToAddress("0x3828134ba7a0629fd52067b80fe696f400eb83dc"),
+			Timeout:      120,
+			Confirmation: 1,
+		},
 	}
 
 	// AllEthashProtocolChanges contains every protocol change (EIPs) introduced
@@ -203,18 +223,18 @@ var (
 	//
 	// This configuration is intentionally not using keyed fields to force anyone
 	// adding flags to the config to also have to set these fields.
-	AllEthashProtocolChanges = &ChainConfig{big.NewInt(1337), 0, big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil, nil}
+	AllEthashProtocolChanges = &ChainConfig{big.NewInt(1337), 0, big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil, nil, nil}
 
 	// AllCliqueProtocolChanges contains every protocol change (EIPs) introduced
 	// and accepted by the Ethereum core developers into the Clique consensus.
 	//
 	// This configuration is intentionally not using keyed fields to force anyone
 	// adding flags to the config to also have to set these fields.
-	AllCliqueProtocolChanges = &ChainConfig{big.NewInt(1337), 0, big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, &CliqueConfig{Period: 0, Epoch: 30000}, nil}
+	AllCliqueProtocolChanges = &ChainConfig{big.NewInt(1337), 0, big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, &CliqueConfig{Period: 0, Epoch: 30000}, nil, nil}
 
-	AllDexconProtocolChanges = &ChainConfig{big.NewInt(1337), 0, big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, nil, new(DexconConfig)}
+	AllDexconProtocolChanges = &ChainConfig{big.NewInt(1337), 0, big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, nil, new(DexconConfig), new(RecoveryConfig)}
 
-	TestChainConfig = &ChainConfig{big.NewInt(1), 0, big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil, nil}
+	TestChainConfig = &ChainConfig{big.NewInt(1), 0, big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil, nil, nil}
 	TestRules       = TestChainConfig.Rules(new(big.Int))
 
 	// Ethereum MainnetChainConfig is the chain parameters to run a node on the main network.
@@ -292,6 +312,9 @@ type ChainConfig struct {
 	Ethash *EthashConfig `json:"ethash,omitempty"`
 	Clique *CliqueConfig `json:"clique,omitempty"`
 	Dexcon *DexconConfig `json:"dexcon,omitempty"`
+
+	// Dexcon Recovery
+	Recovery *RecoveryConfig `json:"recovery,omitempty"`
 }
 
 // EthashConfig is the consensus engine configs for proof-of-work based sealing.
@@ -365,6 +388,12 @@ func (d *DexconConfig) String() string {
 	)
 }
 
+type RecoveryConfig struct {
+	Contract     common.Address `json:"contract"`
+	Timeout      int            `json:"timeout"`
+	Confirmation int            `json:"confirmation"`
+}
+
 // String implements the fmt.Stringer interface.
 func (c *ChainConfig) String() string {
 	var engine interface{}
diff --git a/params/gen_dexcon_config.go b/params/gen_dexcon_config.go
index 1afe11f56..38753916a 100644
--- a/params/gen_dexcon_config.go
+++ b/params/gen_dexcon_config.go
@@ -22,6 +22,7 @@ func (d DexconConfig) MarshalJSON() ([]byte, error) {
 		MiningVelocity    float32                 `json:"miningVelocity"`
 		NextHalvingSupply *math.HexOrDecimal256   `json:"nextHalvingSupply"`
 		LastHalvedAmount  *math.HexOrDecimal256   `json:"lastHalvedAmount"`
+		MinGasPrice       *math.HexOrDecimal256   `json:"minGasPrice"`
 		BlockGasLimit     uint64                  `json:"blockGasLimit"`
 		LambdaBA          uint64                  `json:"lambdaBA"`
 		LambdaDKG         uint64                  `json:"lambdaDKG"`
@@ -30,7 +31,6 @@ func (d DexconConfig) MarshalJSON() ([]byte, error) {
 		RoundLength       uint64                  `json:"roundLength"`
 		MinBlockInterval  uint64                  `json:"minBlockInterval"`
 		FineValues        []*math.HexOrDecimal256 `json:"fineValues"`
-		MinGasPrice       *math.HexOrDecimal256   `json:"minGasPrice"`
 	}
 	var enc DexconConfig
 	enc.GenesisCRSText = d.GenesisCRSText
@@ -40,6 +40,7 @@ func (d DexconConfig) MarshalJSON() ([]byte, error) {
 	enc.MiningVelocity = d.MiningVelocity
 	enc.NextHalvingSupply = (*math.HexOrDecimal256)(d.NextHalvingSupply)
 	enc.LastHalvedAmount = (*math.HexOrDecimal256)(d.LastHalvedAmount)
+	enc.MinGasPrice = (*math.HexOrDecimal256)(d.MinGasPrice)
 	enc.BlockGasLimit = d.BlockGasLimit
 	enc.LambdaBA = d.LambdaBA
 	enc.LambdaDKG = d.LambdaDKG
@@ -53,7 +54,6 @@ func (d DexconConfig) MarshalJSON() ([]byte, error) {
 			enc.FineValues[k] = (*math.HexOrDecimal256)(v)
 		}
 	}
-	enc.MinGasPrice = (*math.HexOrDecimal256)(d.MinGasPrice)
 	return json.Marshal(&enc)
 }
 
@@ -67,6 +67,7 @@ func (d *DexconConfig) UnmarshalJSON(input []byte) error {
 		MiningVelocity    *float32                `json:"miningVelocity"`
 		NextHalvingSupply *math.HexOrDecimal256   `json:"nextHalvingSupply"`
 		LastHalvedAmount  *math.HexOrDecimal256   `json:"lastHalvedAmount"`
+		MinGasPrice       *math.HexOrDecimal256   `json:"minGasPrice"`
 		BlockGasLimit     *uint64                 `json:"blockGasLimit"`
 		LambdaBA          *uint64                 `json:"lambdaBA"`
 		LambdaDKG         *uint64                 `json:"lambdaDKG"`
@@ -75,7 +76,6 @@ func (d *DexconConfig) UnmarshalJSON(input []byte) error {
 		RoundLength       *uint64                 `json:"roundLength"`
 		MinBlockInterval  *uint64                 `json:"minBlockInterval"`
 		FineValues        []*math.HexOrDecimal256 `json:"fineValues"`
-		MinGasPrice       *math.HexOrDecimal256   `json:"minGasPrice"`
 	}
 	var dec DexconConfig
 	if err := json.Unmarshal(input, &dec); err != nil {
@@ -102,6 +102,9 @@ func (d *DexconConfig) UnmarshalJSON(input []byte) error {
 	if dec.LastHalvedAmount != nil {
 		d.LastHalvedAmount = (*big.Int)(dec.LastHalvedAmount)
 	}
+	if dec.MinGasPrice != nil {
+		d.MinGasPrice = (*big.Int)(dec.MinGasPrice)
+	}
 	if dec.BlockGasLimit != nil {
 		d.BlockGasLimit = *dec.BlockGasLimit
 	}
@@ -129,8 +132,5 @@ func (d *DexconConfig) UnmarshalJSON(input []byte) error {
 			d.FineValues[k] = (*big.Int)(v)
 		}
 	}
-	if dec.MinGasPrice != nil {
-		d.MinGasPrice = (*big.Int)(dec.MinGasPrice)
-	}
 	return nil
 }