[slashing] Create Slasher interface, thread through to Accumulate in reward

consensus/engine/consensus_engine.go

@@ -10,6 +10,7 @@ import (
 	"github.com/harmony-one/harmony/core/types"
 	"github.com/harmony-one/harmony/internal/params"
 	"github.com/harmony-one/harmony/shard"
+	"github.com/harmony-one/harmony/staking/slash"
 	staking "github.com/harmony-one/harmony/staking/types"
 )
 
@@ -83,6 +84,12 @@ type Engine interface {
 	// SetRewarder assigns the Distributor used in block reward
 	SetRewarder(reward.Distributor)
 
+	// Slasher handles slashing accounts due to inavailibility or double-signing
+	Slasher() slash.Slasher
+
+	// SetSlasher assigns the slasher used
+	SetSlasher(slash.Slasher)
+
 	// Finalize runs any post-transaction state modifications (e.g. block rewards)
 	// and assembles the final block.
 	// Note: The block header and state database might be updated to reflect any

consensus/quorum/quorum.go

@@ -223,27 +223,43 @@ func (s *cIdentities) ReadAllSignatures(p Phase) []*bls.Sign {
 	return sigs
 }
 
-func newMapBackedSignatureReader() SignatureReader {
-	return &cIdentities{
+func newMapBackedSignatureReader() cIdentities {
+	return cIdentities{
 		[]*bls.PublicKey{}, map[string]*bls.Sign{},
 		map[string]*bls.Sign{}, map[string]*bls.Sign{},
 	}
 }
 
+func (c *composite) ShouldSlash(shard.BlsPublicKey) bool {
+	s, _ := c.shardIDProvider()
+	switch s {
+	case shard.BeaconChainShardID:
+		return true
+	default:
+		return false
+	}
+}
+
+type composite struct {
+	cIdentities
+	depInject
+}
+
 // NewDecider ..
 func NewDecider(p Policy) Decider {
 	signatureStore := newMapBackedSignatureReader()
-	dependencies := &depInject{}
+	dependencies := depInject{}
+	c := &composite{signatureStore, dependencies}
 	switch p {
 	case SuperMajorityVote:
-		return &uniformVoteWeight{signatureStore, dependencies}
+		return &uniformVoteWeight{&c.cIdentities, &c.depInject}
 	case SuperMajorityStake:
 		return &stakedVoteWeight{
-			signatureStore,
-			dependencies,
+			&c.cIdentities, &c.depInject,
 			map[[shard.PublicKeySizeInBytes]byte]stakedVoter{},
 			big.NewInt(0),
 		}
+
 	default:
 		// Should not be possible
 		return nil

internal/chain/engine.go

@@ -16,6 +16,7 @@ import (
 	"github.com/harmony-one/harmony/internal/utils"
 	"github.com/harmony-one/harmony/shard"
 	"github.com/harmony-one/harmony/shard/committee"
+	"github.com/harmony-one/harmony/staking/slash"
 	staking "github.com/harmony-one/harmony/staking/types"
 	"github.com/pkg/errors"
 	"golang.org/x/crypto/sha3"
@@ -23,10 +24,11 @@ import (
 
 type engineImpl struct {
 	d reward.Distributor
+	s slash.Slasher
 }
 
 // Engine is an algorithm-agnostic consensus engine.
-var Engine = &engineImpl{nil}
+var Engine = &engineImpl{nil, nil}
 
 // Rewarder handles the distribution of block rewards
 func (e *engineImpl) Rewarder() reward.Distributor {
@@ -38,6 +40,16 @@ func (e *engineImpl) SetRewarder(d reward.Distributor) {
 	e.d = d
 }
 
+// Slasher handles slashing accounts due to inavailibility or double-signing
+func (e *engineImpl) Slasher() slash.Slasher {
+	return e.s
+}
+
+// SetSlasher assigns the slasher used
+func (e *engineImpl) SetSlasher(s slash.Slasher) {
+	e.s = s
+}
+
 // SealHash returns the hash of a block prior to it being sealed.
 func (e *engineImpl) SealHash(header *block.Header) (hash common.Hash) {
 	hasher := sha3.NewLegacyKeccak256()
@@ -170,8 +182,7 @@ func (e *engineImpl) Finalize(
 	incxs []*types.CXReceiptsProof, stks []*staking.StakingTransaction) (*types.Block, error) {
 	// Accumulate any block and uncle rewards and commit the final state root
 	// Header seems complete, assemble into a block and return
-	// TODO: Block rewards should be done only in beacon chain based on cross-links
-	if err := AccumulateRewards(chain, state, header, e.Rewarder()); err != nil {
+	if err := AccumulateRewards(chain, state, header, e.Rewarder(), e.Slasher()); err != nil {
 		return nil, ctxerror.New("cannot pay block reward").WithCause(err)
 	}
 

internal/chain/reward.go

@@ -14,6 +14,7 @@ import (
 	common2 "github.com/harmony-one/harmony/internal/common"
 	"github.com/harmony-one/harmony/internal/ctxerror"
 	"github.com/harmony-one/harmony/internal/utils"
+	"github.com/harmony-one/harmony/staking/slash"
 	"github.com/pkg/errors"
 )
 
@@ -27,7 +28,9 @@ var (
 // reward. The total reward consists of the static block reward and rewards for
 // included uncles. The coinbase of each uncle block is also rewarded.
 func AccumulateRewards(
-	bc engine.ChainReader, state *state.DB, header *block.Header, rewarder reward.Distributor,
+	bc engine.ChainReader, state *state.DB,
+	header *block.Header, rewarder reward.Distributor,
+	slasher slash.Slasher,
 ) error {
 	blockNum := header.Number().Uint64()
 	if blockNum == 0 {

node/node.go

@@ -33,6 +33,7 @@ import (
 	p2p_host "github.com/harmony-one/harmony/p2p/host"
 	"github.com/harmony-one/harmony/shard"
 	"github.com/harmony-one/harmony/shard/committee"
+	"github.com/harmony-one/harmony/staking/slash"
 	staking "github.com/harmony-one/harmony/staking/types"
 )
 
@@ -441,6 +442,8 @@ func New(host p2p.Host, consensusObj *consensus.Consensus, chainDBFactory shardc
 		node.pendingStakingTransactions = make(map[common.Hash]*staking.StakingTransaction)
 		node.Consensus.VerifiedNewBlock = make(chan *types.Block)
 		chain.Engine.SetRewarder(node.Consensus.Decider.(reward.Distributor))
+		chain.Engine.SetSlasher(node.Consensus.Decider.(slash.Slasher))
+
 		// the sequence number is the next block number to be added in consensus protocol, which is always one more than current chain header block
 		node.Consensus.SetBlockNum(blockchain.CurrentBlock().NumberU64() + 1)
 

staking/slash/slasher.go

@@ -0,0 +1,8 @@
+package slash
+
+import "github.com/harmony-one/harmony/shard"
+
+// Slasher ..
+type Slasher interface {
+	ShouldSlash(shard.BlsPublicKey) bool
+}