// This function either appends a new block at the end of the existing chain
// in which case it also applies all the transactions to the unspent database.
// If the block does is not the heighest, it is added to the chain, but maked
// as an orphan - its transaction will be verified only if the chain would swap
// to its branch later on.
func (ch *Chain) AcceptBlock(bl *btc.Block) (e error) {
prevblk, ok := ch.BlockIndex[btc.NewUint256(bl.ParentHash()).BIdx()]
if !ok {
panic("This should not happen")
}
// create new BlockTreeNode
cur := new(BlockTreeNode)
cur.BlockHash = bl.Hash
cur.Parent = prevblk
cur.Height = prevblk.Height + 1
cur.BlockSize = uint32(len(bl.Raw))
cur.TxCount = uint32(bl.TxCount)
copy(cur.BlockHeader[:], bl.Raw[:80])
// Add this block to the block index
ch.BlockIndexAccess.Lock()
prevblk.addChild(cur)
ch.BlockIndex[cur.BlockHash.BIdx()] = cur
ch.BlockIndexAccess.Unlock()
if ch.BlockTreeEnd == prevblk {
// The head of out chain - apply the transactions
var changes *BlockChanges
changes, e = ch.ProcessBlockTransactions(bl, cur.Height, bl.LastKnownHeight)
if e != nil {
// ProcessBlockTransactions failed, so trash the block.
println("ProcessBlockTransactions ", cur.BlockHash.String(), cur.Height, e.Error())
ch.BlockIndexAccess.Lock()
cur.Parent.delChild(cur)
delete(ch.BlockIndex, cur.BlockHash.BIdx())
ch.BlockIndexAccess.Unlock()
} else {
// ProcessBlockTransactions succeeded, so save the block as "trusted".
bl.Trusted = true
ch.Blocks.BlockAdd(cur.Height, bl)
// Apply the block's trabnsactions to the unspent database:
ch.Unspent.CommitBlockTxs(changes, bl.Hash.Hash[:])
if !ch.DoNotSync {
ch.Blocks.Sync()
}
ch.BlockTreeEnd = cur // Advance the head
}
} else {
// The block's parent is not the current head of the chain...
// Save the block, though do not makt it as "trusted" just yet
ch.Blocks.BlockAdd(cur.Height, bl)
// If it has a bigger height than the current head,
// ... move the coin state into a new branch.
if cur.Height > ch.BlockTreeEnd.Height {
ch.MoveToBlock(cur)
}
}
return
}
func chkblock(bl *btc.Block) (er error) {
// Check timestamp (must not be higher than now +2 hours)
if int64(bl.BlockTime()) > time.Now().Unix()+2*60*60 {
er = errors.New("CheckBlock() : block timestamp too far in the future")
return
}
MemBlockChainMutex.Lock()
if prv, pres := MemBlockChain.BlockIndex[bl.Hash.BIdx()]; pres {
MemBlockChainMutex.Unlock()
if prv.Parent == nil {
// This is genesis block
er = errors.New("Genesis")
return
} else {
return
}
}
prevblk, ok := MemBlockChain.BlockIndex[btc.NewUint256(bl.ParentHash()).BIdx()]
if !ok {
er = errors.New("CheckBlock: " + bl.Hash.String() + " parent not found")
return
}
// Check proof of work
gnwr := MemBlockChain.GetNextWorkRequired(prevblk, bl.BlockTime())
if bl.Bits() != gnwr {
if !Testnet || ((prevblk.Height+1)%2016) != 0 {
MemBlockChainMutex.Unlock()
er = errors.New(fmt.Sprint("CheckBlock: Incorrect proof of work at block", prevblk.Height+1))
return
}
}
cur := new(chain.BlockTreeNode)
cur.BlockHash = bl.Hash
cur.Parent = prevblk
cur.Height = prevblk.Height + 1
cur.TxCount = uint32(bl.TxCount)
copy(cur.BlockHeader[:], bl.Raw[:80])
prevblk.Childs = append(prevblk.Childs, cur)
MemBlockChain.BlockIndex[cur.BlockHash.BIdx()] = cur
MemBlockChainMutex.Unlock()
LastBlock.Mutex.Lock()
if cur.Height > LastBlock.node.Height {
LastBlock.node = cur
}
LastBlock.Mutex.Unlock()
return
}
func (ch *Chain) CheckBlock(bl *btc.Block) (er error, dos bool, maybelater bool) {
// Size limits
if len(bl.Raw) < 81 || len(bl.Raw) > btc.MAX_BLOCK_SIZE {
er = errors.New("CheckBlock() : size limits failed")
dos = true
return
}
if bl.Version() == 0 {
er = errors.New("CheckBlock() : Block version 0 not allowed")
dos = true
return
}
// Check timestamp (must not be higher than now +2 hours)
if int64(bl.BlockTime()) > time.Now().Unix()+2*60*60 {
er = errors.New("CheckBlock() : block timestamp too far in the future")
dos = true
return
}
if prv, pres := ch.BlockIndex[bl.Hash.BIdx()]; pres {
if prv.Parent == nil {
// This is genesis block
er = errors.New("Genesis")
return
} else {
er = errors.New("CheckBlock: " + bl.Hash.String() + " already in")
return
}
}
prevblk, ok := ch.BlockIndex[btc.NewUint256(bl.ParentHash()).BIdx()]
if !ok {
er = errors.New("CheckBlock: " + bl.Hash.String() + " parent not found")
maybelater = true
return
}
height := prevblk.Height + 1
// Reject the block if it reaches into the chain deeper than our unwind buffer
if prevblk != ch.BlockTreeEnd && int(ch.BlockTreeEnd.Height)-int(height) >= MovingCheckopintDepth {
er = errors.New(fmt.Sprint("CheckBlock: btc.Block ", bl.Hash.String(),
" hooks too deep into the chain: ", height, "/", ch.BlockTreeEnd.Height, " ",
btc.NewUint256(bl.ParentHash()).String()))
return
}
// Check proof of work
gnwr := ch.GetNextWorkRequired(prevblk, bl.BlockTime())
if bl.Bits() != gnwr {
println("AcceptBlock() : incorrect proof of work ", bl.Bits, " at block", height, " exp:", gnwr)
// Here is a "solution" for whatever shit there is in testnet3, that nobody can explain me:
if !ch.testnet() || (height%2016) != 0 {
er = errors.New("CheckBlock: incorrect proof of work")
dos = true
return
}
}
// Count block versions within the Majority Window
var majority_v2, majority_v3 uint
n := prevblk
for cnt := uint(0); cnt < ch.Consensus.Window && n != nil; cnt++ {
ver := binary.LittleEndian.Uint32(n.BlockHeader[0:4])
if ver >= 2 {
majority_v2++
if ver >= 3 {
majority_v3++
}
}
n = n.Parent
}
if bl.Version() < 2 && majority_v2 >= ch.Consensus.RejectBlock {
er = errors.New("CheckBlock() : Rejected nVersion=1 block")
dos = true
return
}
if bl.Version() < 3 && majority_v3 >= ch.Consensus.RejectBlock {
er = errors.New("CheckBlock() : Rejected nVersion=2 block")
dos = true
return
}
if bl.Txs == nil {
er = bl.BuildTxList()
if er != nil {
dos = true
return
}
}
if !bl.Trusted {
if bl.Version() >= 2 && majority_v2 >= ch.Consensus.EnforceUpgrade {
var exp []byte
if height >= 0x800000 {
if height >= 0x80000000 {
exp = []byte{5, byte(height), byte(height >> 8), byte(height >> 16), byte(height >> 24), 0}
} else {
exp = []byte{4, byte(height), byte(height >> 8), byte(height >> 16), byte(height >> 24)}
}
} else {
exp = []byte{3, byte(height), byte(height >> 8), byte(height >> 16)}
}
if len(bl.Txs[0].TxIn[0].ScriptSig) < len(exp) || !bytes.Equal(exp, bl.Txs[0].TxIn[0].ScriptSig[:len(exp)]) {
er = errors.New("CheckBlock() : Unexpected block number in coinbase: " + bl.Hash.String())
dos = true
return
}
}
// This is a stupid check, but well, we need to be satoshi compatible
if len(bl.Txs) == 0 || !bl.Txs[0].IsCoinBase() {
er = errors.New("CheckBlock() : first tx is not coinbase: " + bl.Hash.String())
dos = true
return
}
// Check Merkle Root - that's importnant
if !bytes.Equal(btc.GetMerkel(bl.Txs), bl.MerkleRoot()) {
er = errors.New("CheckBlock() : Merkle Root mismatch")
dos = true
return
}
// Check transactions - this is the most time consuming task
if !CheckTransactions(bl.Txs, height, bl.BlockTime()) {
er = errors.New("CheckBlock() : CheckTransactions() failed")
dos = true
return
}
}
if bl.BlockTime() >= BIP16SwitchTime {
bl.VerifyFlags = script.VER_P2SH
} else {
bl.VerifyFlags = 0
}
if majority_v3 >= ch.Consensus.EnforceUpgrade {
bl.VerifyFlags |= script.VER_DERSIG
}
return
}