prysm-pulse/beacon-chain/core/blocks/validity_conditions.go
2019-08-21 10:04:00 -06:00

67 lines
2.2 KiB
Go

package blocks
import (
"context"
"fmt"
"time"
"github.com/ethereum/go-ethereum/common"
gethTypes "github.com/ethereum/go-ethereum/core/types"
"github.com/pkg/errors"
pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
"github.com/prysmaticlabs/prysm/shared/bytesutil"
"github.com/prysmaticlabs/prysm/shared/params"
"github.com/prysmaticlabs/prysm/shared/roughtime"
)
// IsValidBlock ensures that the block is compliant with the block processing validity conditions.
func IsValidBlock(
ctx context.Context,
state *pb.BeaconState,
block *ethpb.BeaconBlock,
HasBlock func(ctx context.Context, hash [32]byte) bool,
GetPOWBlock func(ctx context.Context, hash common.Hash) (*gethTypes.Block, error),
genesisTime time.Time) error {
// Pre-Processing Condition 1:
// Check that the parent Block has been processed and saved.
parentRoot := bytesutil.ToBytes32(block.ParentRoot)
parentBlock := HasBlock(ctx, parentRoot)
if !parentBlock {
return fmt.Errorf("unprocessed parent block as it is not saved in the db: %#x", parentRoot)
}
h := common.BytesToHash(state.Eth1Data.BlockHash)
powBlock, err := GetPOWBlock(ctx, h)
if err != nil {
return errors.Wrap(err, "unable to retrieve POW chain reference block")
}
// Pre-Processing Condition 2:
// The block pointed to by the state in state.processed_pow_receipt_root has
// been processed in the ETH 1.0 chain.
if powBlock == nil {
return fmt.Errorf("proof-of-Work chain reference in state does not exist: %#x", state.Eth1Data.BlockHash)
}
// Pre-Processing Condition 4:
// The node's local time is greater than or equal to
// state.genesis_time + (block.slot-GENESIS_SLOT)* SECONDS_PER_SLOT.
if !IsSlotValid(block.Slot, genesisTime) {
return fmt.Errorf("slot of block is too high: %d", block.Slot)
}
return nil
}
// IsSlotValid compares the slot to the system clock to determine if the block is valid.
func IsSlotValid(slot uint64, genesisTime time.Time) bool {
secondsSinceGenesis := time.Duration(slot*params.BeaconConfig().SecondsPerSlot) * time.Second
validTimeThreshold := genesisTime.Add(secondsSinceGenesis)
now := roughtime.Now()
isValid := now.After(validTimeThreshold)
return isValid
}