private bool CheckPrevHash(Node node, Block block)
{
// If we don't already have its previous block, shunt it off to holding area until we get it
if (!this.chainIndex.InAnyTip(block.Header.HashPrevBlock))
{
var blockHash = block.GetHash();
//LogPrintf("ProcessBlock: ORPHAN BLOCK %lu, prev=%s\n", (unsigned long)mapOrphanBlocks.size(), pblock->hashPrevBlock.ToString());
// Accept orphans as long as there is a node to request its parents from
if (node != null)
{
// ppcoin: check proof-of-stake
if (block.IsProofOfStake())
{
// Limited duplicity on stake: prevents block flood attack
// Duplicate stake allowed only when there is orphan child block
//if (setStakeSeenOrphan.count(pblock->GetProofOfStake()) && !mapOrphanBlocksByPrev.count(hash))
// return error("ProcessBlock() : duplicate proof-of-stake (%s, %d) for orphan block %s",
// pblock->GetProofOfStake().first.ToString(), pblock->GetProofOfStake().second, hash.ToString());
}
}
var orphan = new OrphanBlock
{
BlockHash = blockHash,
PreviousHash = block.Header.HashPrevBlock,
Block = block,
};
if (block.IsProofOfStake())
{
orphan.Stake = block.GetProofOfStake();
}
if (this.orphanBlocks.TryAdd(blockHash, orphan))
{
if (!this.Context.DownloadMode)
{
if (node != null)
{
// call get blocks
var message = new GetBlocksPayload()
{
BlockLocators = this.chainIndex.Tip.GetLocator(),
HashStop = this.GetOrphanRoot(blockHash)
};
node.SendMessage(message);
// ppcoin: getblocks may not obtain the ancestor block rejected
// earlier by duplicate-stake check so we ask for it again directly
//node.SendMessage(new InvPayload(InventoryType.MSG_BLOCK, block.Header.HashPrevBlock));
}
}
}
return(false);
}
return(true);
}
private uint256 GetOrphanRoot(uint256 hash)
{
var selector = this.orphanBlocks.TryGet(hash);
if (selector == null)
{
return(hash);
}
OrphanBlock prev = null;
while (selector != null)
{
prev = selector;
selector = this.orphanBlocks.TryGet(selector.PreviousHash);
}
return(prev.BlockHash);
}