1 // Copyright (c) 2009-2012 The Bitcoin developers
2 // Copyright (c) 2011-2012 The PPCoin developers
3 // Distributed under the MIT/X11 software license, see the accompanying
4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
6 #include <boost/assign/list_of.hpp> // for 'map_list_of()'
7 #include <boost/foreach.hpp>
9 #include "checkpoints.h"
17 typedef std::map<int, uint256> MapCheckpoints; // hardened checkpoints
20 // What makes a good checkpoint block?
21 // + Is surrounded by blocks with reasonable timestamps
22 // (no blocks before with a timestamp after, none after with
24 // + Contains no strange transactions
26 static MapCheckpoints mapCheckpoints =
27 boost::assign::map_list_of
28 ( 0, hashGenesisBlockOfficial )
29 ; // ppcoin: no checkpoint yet; to be created in future releases
31 bool CheckHardened(int nHeight, const uint256& hash)
33 if (fTestNet) return true; // Testnet has no checkpoints
35 MapCheckpoints::const_iterator i = mapCheckpoints.find(nHeight);
36 if (i == mapCheckpoints.end()) return true;
37 return hash == i->second;
40 int GetTotalBlocksEstimate()
42 if (fTestNet) return 0;
44 return mapCheckpoints.rbegin()->first;
47 CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
50 std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hashGenesisBlock);
51 if (t != mapBlockIndex.end())
56 BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
58 const uint256& hash = i.second;
59 std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
60 if (t != mapBlockIndex.end())
66 // ppcoin: synchronized checkpoint (centrally broadcasted)
67 uint256 hashSyncCheckpoint = 0;
68 uint256 hashPendingCheckpoint = 0;
69 CSyncCheckpoint checkpointMessage;
70 CSyncCheckpoint checkpointMessagePending;
71 uint256 hashInvalidCheckpoint = 0;
72 CCriticalSection cs_hashSyncCheckpoint;
74 // ppcoin: get last synchronized checkpoint
75 CBlockIndex* GetLastSyncCheckpoint()
77 LOCK(cs_hashSyncCheckpoint);
78 if (!mapBlockIndex.count(hashSyncCheckpoint))
79 error("GetSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
81 return mapBlockIndex[hashSyncCheckpoint];
85 // ppcoin: only descendant of current sync-checkpoint is allowed
86 bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
88 if (!mapBlockIndex.count(hashSyncCheckpoint))
89 return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
90 if (!mapBlockIndex.count(hashCheckpoint))
91 return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
93 CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
94 CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
96 if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
98 // Received an older checkpoint, trace back from current checkpoint
99 // to the same height of the received checkpoint to verify
100 // that current checkpoint should be a descendant block
101 CBlockIndex* pindex = pindexSyncCheckpoint;
102 while (pindex->nHeight > pindexCheckpointRecv->nHeight)
103 if (!(pindex = pindex->pprev))
104 return error("ValidateSyncCheckpoint: pprev1 null - block index structure failure");
105 if (pindex->GetBlockHash() != hashCheckpoint)
107 hashInvalidCheckpoint = hashCheckpoint;
108 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is conflicting with current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
110 return false; // ignore older checkpoint
113 // Received checkpoint should be a descendant block of the current
114 // checkpoint. Trace back to the same height of current checkpoint
116 CBlockIndex* pindex = pindexCheckpointRecv;
117 while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
118 if (!(pindex = pindex->pprev))
119 return error("ValidateSyncCheckpoint: pprev2 null - block index structure failure");
120 if (pindex->GetBlockHash() != hashSyncCheckpoint)
122 hashInvalidCheckpoint = hashCheckpoint;
123 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
128 bool WriteSyncCheckpoint(const uint256& hashCheckpoint)
132 if (!txdb.WriteSyncCheckpoint(hashCheckpoint))
135 return error("WriteSyncCheckpoint(): failed to write to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
137 if (!txdb.TxnCommit())
138 return error("WriteSyncCheckpoint(): failed to commit to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
141 Checkpoints::hashSyncCheckpoint = hashCheckpoint;
145 bool AcceptPendingSyncCheckpoint()
147 LOCK(cs_hashSyncCheckpoint);
148 if (hashPendingCheckpoint != 0 && mapBlockIndex.count(hashPendingCheckpoint))
150 if (!ValidateSyncCheckpoint(hashPendingCheckpoint))
152 hashPendingCheckpoint = 0;
153 checkpointMessagePending.SetNull();
158 CBlockIndex* pindexCheckpoint = mapBlockIndex[hashPendingCheckpoint];
159 if (!pindexCheckpoint->IsInMainChain())
162 if (!block.ReadFromDisk(pindexCheckpoint))
163 return error("AcceptPendingSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
164 if (!block.SetBestChain(txdb, pindexCheckpoint))
166 hashInvalidCheckpoint = hashPendingCheckpoint;
167 return error("AcceptPendingSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
172 if (!WriteSyncCheckpoint(hashPendingCheckpoint))
173 return error("AcceptPendingSyncCheckpoint(): failed to write sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
174 hashPendingCheckpoint = 0;
175 checkpointMessage = checkpointMessagePending;
176 checkpointMessagePending.SetNull();
177 printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
178 // relay the checkpoint
179 if (!checkpointMessage.IsNull())
181 BOOST_FOREACH(CNode* pnode, vNodes)
182 checkpointMessage.RelayTo(pnode);
189 // Automatically select a suitable sync-checkpoint
190 uint256 AutoSelectSyncCheckpoint()
192 // Proof-of-work blocks are immediately checkpointed
193 // to defend against 51% attack which rejects other miners block
195 // Select the last proof-of-work block
196 const CBlockIndex *pindex = GetLastBlockIndex(pindexBest, false);
197 // Search forward for a block within max span and maturity window
198 while (pindex->pnext && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN <= pindexBest->GetBlockTime() || pindex->nHeight + nCoinbaseMaturity - 20 <= pindexBest->nHeight))
199 pindex = pindex->pnext;
200 return pindex->GetBlockHash();
203 // Check against synchronized checkpoint
204 bool CheckSync(const uint256& hashBlock, const CBlockIndex* pindexPrev)
206 if (fTestNet) return true; // Testnet has no checkpoints
207 int nHeight = pindexPrev->nHeight + 1;
209 LOCK(cs_hashSyncCheckpoint);
210 // sync-checkpoint should always be accepted block
211 assert(mapBlockIndex.count(hashSyncCheckpoint));
212 const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
214 if (nHeight > pindexSync->nHeight)
216 // trace back to same height as sync-checkpoint
217 const CBlockIndex* pindex = pindexPrev;
218 while (pindex->nHeight > pindexSync->nHeight)
219 if (!(pindex = pindex->pprev))
220 return error("CheckSync: pprev null - block index structure failure");
221 if (pindex->nHeight < pindexSync->nHeight || pindex->GetBlockHash() != hashSyncCheckpoint)
222 return false; // only descendant of sync-checkpoint can pass check
224 if (nHeight == pindexSync->nHeight && hashBlock != hashSyncCheckpoint)
225 return false; // same height with sync-checkpoint
226 if (nHeight < pindexSync->nHeight && !mapBlockIndex.count(hashBlock))
227 return false; // lower height than sync-checkpoint
231 bool WantedByPendingSyncCheckpoint(uint256 hashBlock)
233 LOCK(cs_hashSyncCheckpoint);
234 if (hashPendingCheckpoint == 0)
236 if (hashBlock == hashPendingCheckpoint)
238 if (mapOrphanBlocks.count(hashPendingCheckpoint)
239 && hashBlock == WantedByOrphan(mapOrphanBlocks[hashPendingCheckpoint]))
244 // ppcoin: reset synchronized checkpoint to last hardened checkpoint
245 bool ResetSyncCheckpoint()
247 LOCK(cs_hashSyncCheckpoint);
248 const uint256& hash = mapCheckpoints.rbegin()->second;
249 if (mapBlockIndex.count(hash) && !mapBlockIndex[hash]->IsInMainChain())
251 // checkpoint block accepted but not yet in main chain
252 printf("ResetSyncCheckpoint: SetBestChain to hardened checkpoint %s\n", hash.ToString().c_str());
255 if (!block.ReadFromDisk(mapBlockIndex[hash]))
256 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
257 if (!block.SetBestChain(txdb, mapBlockIndex[hash]))
259 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
263 else if(!mapBlockIndex.count(hash))
265 // checkpoint block not yet accepted
266 hashPendingCheckpoint = hash;
267 checkpointMessagePending.SetNull();
268 printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
271 BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
273 const uint256& hash = i.second;
274 if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
276 if (!WriteSyncCheckpoint(hash))
277 return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
278 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
286 void AskForPendingSyncCheckpoint(CNode* pfrom)
288 LOCK(cs_hashSyncCheckpoint);
289 if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
290 pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
293 bool SetCheckpointPrivKey(std::string strPrivKey)
295 // Test signing a sync-checkpoint with genesis block
296 CSyncCheckpoint checkpoint;
297 checkpoint.hashCheckpoint = hashGenesisBlock;
298 CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
299 sMsg << (CUnsignedSyncCheckpoint)checkpoint;
300 checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
302 std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
304 key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
305 if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
308 // Test signing successful, proceed
309 CSyncCheckpoint::strMasterPrivKey = strPrivKey;
313 bool SendSyncCheckpoint(uint256 hashCheckpoint)
315 CSyncCheckpoint checkpoint;
316 checkpoint.hashCheckpoint = hashCheckpoint;
317 CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
318 sMsg << (CUnsignedSyncCheckpoint)checkpoint;
319 checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
321 if (CSyncCheckpoint::strMasterPrivKey.empty())
322 return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
323 std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
325 key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
326 if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
327 return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
329 if(!checkpoint.ProcessSyncCheckpoint(NULL))
331 printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
338 BOOST_FOREACH(CNode* pnode, vNodes)
339 checkpoint.RelayTo(pnode);
344 // Is the sync-checkpoint outside maturity window?
345 bool IsMatureSyncCheckpoint()
347 LOCK(cs_hashSyncCheckpoint);
348 // sync-checkpoint should always be accepted block
349 assert(mapBlockIndex.count(hashSyncCheckpoint));
350 const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
351 return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
352 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
356 // ppcoin: sync-checkpoint master key
357 const std::string CSyncCheckpoint::strMasterPubKey = "04c0c707c28533fd5c9f79d2d3a2d80dff259ad8f915241cd14608fb9bc07c74830efe8438f2b272a866b4af5e0c2cc2a9909972aefbd976937e39f46bb38c277c";
359 std::string CSyncCheckpoint::strMasterPrivKey = "";
361 // ppcoin: verify signature of sync-checkpoint message
362 bool CSyncCheckpoint::CheckSignature()
365 if (!key.SetPubKey(ParseHex(CSyncCheckpoint::strMasterPubKey)))
366 return error("CSyncCheckpoint::CheckSignature() : SetPubKey failed");
367 if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
368 return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
370 // Now unserialize the data
371 CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
372 sMsg >> *(CUnsignedSyncCheckpoint*)this;
376 // ppcoin: process synchronized checkpoint
377 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
379 if (!CheckSignature())
382 LOCK(Checkpoints::cs_hashSyncCheckpoint);
383 if (!mapBlockIndex.count(hashCheckpoint))
385 // We haven't received the checkpoint chain, keep the checkpoint as pending
386 Checkpoints::hashPendingCheckpoint = hashCheckpoint;
387 Checkpoints::checkpointMessagePending = *this;
388 printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
389 // Ask this guy to fill in what we're missing
392 pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
393 // ask directly as well in case rejected earlier by duplicate
394 // proof-of-stake because getblocks may not get it this time
395 pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
400 if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
404 CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
405 if (!pindexCheckpoint->IsInMainChain())
407 // checkpoint chain received but not yet main chain
409 if (!block.ReadFromDisk(pindexCheckpoint))
410 return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
411 if (!block.SetBestChain(txdb, pindexCheckpoint))
413 Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
414 return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
419 if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
420 return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
421 Checkpoints::checkpointMessage = *this;
422 Checkpoints::hashPendingCheckpoint = 0;
423 Checkpoints::checkpointMessagePending.SetNull();
424 printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());