// validHeader does some early, low computation verification on the block.
func (cs *State) validHeader(b types.Block) error {
// Grab the parent of the block and verify the ID of the child meets the
// target. This is done as early as possible to enforce that any
// block-related DoS must use blocks that have sufficient work.
parent, exists := cs.blockMap[b.ParentID]
if !exists {
return ErrOrphan
}
if !b.CheckTarget(parent.childTarget) {
return ErrMissedTarget
}
// Check that the block is below the size limit.
if uint64(len(encoding.Marshal(b))) > types.BlockSizeLimit {
return ErrLargeBlock
}
// Check that the timestamp is not in 'the past', where the past is defined
// by earliestChildTimestamp.
if parent.earliestChildTimestamp() > b.Timestamp {
return ErrEarlyTimestamp
}
// If the block is in the extreme future, return an error and do nothing
// more with the block. There is an assumption that by the time the extreme
// future arrives, this block will no longer be a part of the longest fork
// because it will have been ignored by all of the miners.
if b.Timestamp > types.CurrentTimestamp()+types.ExtremeFutureThreshold {
return ErrExtremeFutureTimestamp
}
// Verify that the miner payouts are valid.
if !b.CheckMinerPayouts(parent.height + 1) {
return ErrBadMinerPayouts
}
// If the block is in the near future, but too far to be acceptable, then
// the block will be saved and added to the consensus set after it is no
// longer too far in the future. This is the last check because it's an
// expensive check, and not worth performing if the payouts are incorrect.
if b.Timestamp > types.CurrentTimestamp()+types.FutureThreshold {
go func() {
time.Sleep(time.Duration(b.Timestamp-(types.CurrentTimestamp()+types.FutureThreshold)) * time.Second)
lockID := cs.mu.Lock()
defer cs.mu.Unlock(lockID)
cs.acceptBlock(b) // NOTE: Error is not handled.
}()
return ErrFutureTimestamp
}
return nil
}
// validHeader does some early, low computation verification on the block.
func (cs *ConsensusSet) validHeader(tx *bolt.Tx, b types.Block) error {
// See if the block is known already.
id := b.ID()
_, exists := cs.dosBlocks[id]
if exists {
return errDoSBlock
}
// Check if the block is already known.
blockMap := tx.Bucket(BlockMap)
if blockMap.Get(id[:]) != nil {
return modules.ErrBlockKnown
}
// Check for the parent.
parentBytes := blockMap.Get(b.ParentID[:])
if parentBytes == nil {
return errOrphan
}
var parent processedBlock
err := encoding.Unmarshal(parentBytes, &parent)
if err != nil {
return err
}
// Check that the target of the new block is sufficient.
if !b.CheckTarget(parent.ChildTarget) {
return modules.ErrBlockUnsolved
}
// Check that the timestamp is not too far in the past to be
// acceptable.
if earliestChildTimestamp(blockMap, &parent) > b.Timestamp {
return errEarlyTimestamp
}
// Check that the block is below the size limit.
if uint64(len(encoding.Marshal(b))) > types.BlockSizeLimit {
return errLargeBlock
}
// If the block is in the extreme future, return an error and do nothing
// more with the block. There is an assumption that by the time the extreme
// future arrives, this block will no longer be a part of the longest fork
// because it will have been ignored by all of the miners.
if b.Timestamp > types.CurrentTimestamp()+types.ExtremeFutureThreshold {
return errExtremeFutureTimestamp
}
// Verify that the miner payouts are valid.
if !b.CheckMinerPayouts(parent.Height + 1) {
return errBadMinerPayouts
}
// If the block is in the near future, but too far to be acceptable, then
// the block will be saved and added to the consensus set after it is no
// longer too far in the future. This is the last check because it's an
// expensive check, and not worth performing if the payouts are incorrect.
if b.Timestamp > types.CurrentTimestamp()+types.FutureThreshold {
go func() {
time.Sleep(time.Duration(b.Timestamp-(types.CurrentTimestamp()+types.FutureThreshold)) * time.Second)
cs.AcceptBlock(b) // NOTE: Error is not handled.
}()
return errFutureTimestamp
}
return nil
}
