1 // Copyright (c) 2009-2012 The Bitcoin developers
2 // Distributed under the MIT/X11 software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 #include <boost/assign/list_of.hpp> // for 'map_list_of()'
6 #include <boost/foreach.hpp>
8 #include "checkpoints.h"
18 uint256 hashCheckPoint;
22 typedef std::map<int, Checkpoint> MapCheckpoints;
24 Checkpoint initCheckpoint(uint256 hashCheckPoint, unsigned int nTime)
26 return {hashCheckPoint, nTime};
30 // What makes a good checkpoint block?
31 // + Is surrounded by blocks with reasonable timestamps
32 // (no blocks before with a timestamp after, none after with
34 // + Contains no strange transactions
36 static MapCheckpoints mapCheckpoints =
37 boost::assign::map_list_of
38 ( 0, initCheckpoint(hashGenesisBlock, 1360105017) )
39 ( 9690, initCheckpoint(uint256("0x00000000026561450859c46868099e0df6068a538f038cb18988fd8d47dcdaf5"), 1362791423) )
40 ( 13560, initCheckpoint(uint256("0xa1591a0fcbf11f282d671581edb9f0aadcd06fee69761081e0a3245914c13729"), 1364674052) )
41 ( 37092, initCheckpoint(uint256("0x0000000000a38c2f98556f46793b453e92d8fab2d31c0b93fd08bcf78e56099d"), 1376677203) )
44 // TestNet has no checkpoints
45 static MapCheckpoints mapCheckpointsTestnet =
46 boost::assign::map_list_of
47 ( 0, initCheckpoint(hashGenesisBlockTestNet, 1360105017) )
50 bool CheckHardened(int nHeight, const uint256& hash)
52 MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
54 MapCheckpoints::const_iterator i = checkpoints.find(nHeight);
55 if (i == checkpoints.end()) return true;
56 return hash == i->second.hashCheckPoint;
59 int GetTotalBlocksEstimate()
61 MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
63 return checkpoints.rbegin()->first;
66 int GetLastCheckpointTime()
68 MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
70 return checkpoints.rbegin()->second.nTime;
73 CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
75 MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
77 BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, checkpoints)
79 const uint256& hash = i.second.hashCheckPoint;
80 std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
81 if (t != mapBlockIndex.end())
87 // ppcoin: synchronized checkpoint (centrally broadcasted)
88 uint256 hashSyncCheckpoint = 0;
89 uint256 hashPendingCheckpoint = 0;
90 CSyncCheckpoint checkpointMessage;
91 CSyncCheckpoint checkpointMessagePending;
92 uint256 hashInvalidCheckpoint = 0;
93 CCriticalSection cs_hashSyncCheckpoint;
95 // ppcoin: get last synchronized checkpoint
96 CBlockIndex* GetLastSyncCheckpoint()
98 LOCK(cs_hashSyncCheckpoint);
99 if (!mapBlockIndex.count(hashSyncCheckpoint))
100 error("GetSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
102 return mapBlockIndex[hashSyncCheckpoint];
106 // ppcoin: only descendant of current sync-checkpoint is allowed
107 bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
109 if (!mapBlockIndex.count(hashSyncCheckpoint))
110 return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
111 if (!mapBlockIndex.count(hashCheckpoint))
112 return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
114 CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
115 CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
117 if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
119 // Received an older checkpoint, trace back from current checkpoint
120 // to the same height of the received checkpoint to verify
121 // that current checkpoint should be a descendant block
122 CBlockIndex* pindex = pindexSyncCheckpoint;
123 while (pindex->nHeight > pindexCheckpointRecv->nHeight)
124 if (!(pindex = pindex->pprev))
125 return error("ValidateSyncCheckpoint: pprev1 null - block index structure failure");
126 if (pindex->GetBlockHash() != hashCheckpoint)
128 hashInvalidCheckpoint = hashCheckpoint;
129 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is conflicting with current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
131 return false; // ignore older checkpoint
134 // Received checkpoint should be a descendant block of the current
135 // checkpoint. Trace back to the same height of current checkpoint
137 CBlockIndex* pindex = pindexCheckpointRecv;
138 while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
139 if (!(pindex = pindex->pprev))
140 return error("ValidateSyncCheckpoint: pprev2 null - block index structure failure");
141 if (pindex->GetBlockHash() != hashSyncCheckpoint)
143 hashInvalidCheckpoint = hashCheckpoint;
144 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
149 bool WriteSyncCheckpoint(const uint256& hashCheckpoint)
153 if (!txdb.WriteSyncCheckpoint(hashCheckpoint))
156 return error("WriteSyncCheckpoint(): failed to write to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
158 if (!txdb.TxnCommit())
159 return error("WriteSyncCheckpoint(): failed to commit to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
162 Checkpoints::hashSyncCheckpoint = hashCheckpoint;
166 bool AcceptPendingSyncCheckpoint()
168 LOCK(cs_hashSyncCheckpoint);
169 if (hashPendingCheckpoint != 0 && mapBlockIndex.count(hashPendingCheckpoint))
171 if (!ValidateSyncCheckpoint(hashPendingCheckpoint))
173 hashPendingCheckpoint = 0;
174 checkpointMessagePending.SetNull();
179 CBlockIndex* pindexCheckpoint = mapBlockIndex[hashPendingCheckpoint];
180 if (!pindexCheckpoint->IsInMainChain())
183 if (!block.ReadFromDisk(pindexCheckpoint))
184 return error("AcceptPendingSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
185 if (!block.SetBestChain(txdb, pindexCheckpoint))
187 hashInvalidCheckpoint = hashPendingCheckpoint;
188 return error("AcceptPendingSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
193 if (!WriteSyncCheckpoint(hashPendingCheckpoint))
194 return error("AcceptPendingSyncCheckpoint(): failed to write sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
195 hashPendingCheckpoint = 0;
196 checkpointMessage = checkpointMessagePending;
197 checkpointMessagePending.SetNull();
198 printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
199 // relay the checkpoint
200 if (!checkpointMessage.IsNull())
202 BOOST_FOREACH(CNode* pnode, vNodes)
203 checkpointMessage.RelayTo(pnode);
210 // Automatically select a suitable sync-checkpoint
211 uint256 AutoSelectSyncCheckpoint()
213 // Proof-of-work blocks are immediately checkpointed
214 // to defend against 51% attack which rejects other miners block
216 // Select the last proof-of-work block
217 const CBlockIndex *pindex = GetLastBlockIndex(pindexBest, false);
218 // Search forward for a block within max span and maturity window
219 while (pindex->pnext && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN <= pindexBest->GetBlockTime() || pindex->nHeight + std::min(6, nCoinbaseMaturity - 20) <= pindexBest->nHeight))
220 pindex = pindex->pnext;
221 return pindex->GetBlockHash();
224 // Check against synchronized checkpoint
225 bool CheckSync(const uint256& hashBlock, const CBlockIndex* pindexPrev)
227 if (fTestNet) return true; // Testnet has no checkpoints
228 int nHeight = pindexPrev->nHeight + 1;
230 LOCK(cs_hashSyncCheckpoint);
231 // sync-checkpoint should always be accepted block
232 assert(mapBlockIndex.count(hashSyncCheckpoint));
233 const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
235 if (nHeight > pindexSync->nHeight)
237 // trace back to same height as sync-checkpoint
238 const CBlockIndex* pindex = pindexPrev;
239 while (pindex->nHeight > pindexSync->nHeight)
240 if (!(pindex = pindex->pprev))
241 return error("CheckSync: pprev null - block index structure failure");
242 if (pindex->nHeight < pindexSync->nHeight || pindex->GetBlockHash() != hashSyncCheckpoint)
243 return false; // only descendant of sync-checkpoint can pass check
245 if (nHeight == pindexSync->nHeight && hashBlock != hashSyncCheckpoint)
246 return false; // same height with sync-checkpoint
247 if (nHeight < pindexSync->nHeight && !mapBlockIndex.count(hashBlock))
248 return false; // lower height than sync-checkpoint
252 bool WantedByPendingSyncCheckpoint(uint256 hashBlock)
254 LOCK(cs_hashSyncCheckpoint);
255 if (hashPendingCheckpoint == 0)
257 if (hashBlock == hashPendingCheckpoint)
259 if (mapOrphanBlocks.count(hashPendingCheckpoint)
260 && hashBlock == WantedByOrphan(mapOrphanBlocks[hashPendingCheckpoint]))
265 // ppcoin: reset synchronized checkpoint to last hardened checkpoint
266 bool ResetSyncCheckpoint()
268 LOCK(cs_hashSyncCheckpoint);
269 const uint256& hash = mapCheckpoints.rbegin()->second.hashCheckPoint;
270 if (mapBlockIndex.count(hash) && !mapBlockIndex[hash]->IsInMainChain())
272 // checkpoint block accepted but not yet in main chain
273 printf("ResetSyncCheckpoint: SetBestChain to hardened checkpoint %s\n", hash.ToString().c_str());
276 if (!block.ReadFromDisk(mapBlockIndex[hash]))
277 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
278 if (!block.SetBestChain(txdb, mapBlockIndex[hash]))
280 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
284 else if(!mapBlockIndex.count(hash))
286 // checkpoint block not yet accepted
287 hashPendingCheckpoint = hash;
288 checkpointMessagePending.SetNull();
289 printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
292 BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
294 const uint256& hash = i.second.hashCheckPoint;
295 if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
297 if (!WriteSyncCheckpoint(hash))
298 return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
299 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
307 void AskForPendingSyncCheckpoint(CNode* pfrom)
309 LOCK(cs_hashSyncCheckpoint);
310 if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
311 pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
314 bool SetCheckpointPrivKey(std::string strPrivKey)
316 // Test signing a sync-checkpoint with genesis block
317 CSyncCheckpoint checkpoint;
318 checkpoint.hashCheckpoint = !fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet;
319 CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
320 sMsg << (CUnsignedSyncCheckpoint)checkpoint;
321 checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
323 std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
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))
329 // Test signing successful, proceed
330 CSyncCheckpoint::strMasterPrivKey = strPrivKey;
334 bool SendSyncCheckpoint(uint256 hashCheckpoint)
336 CSyncCheckpoint checkpoint;
337 checkpoint.hashCheckpoint = hashCheckpoint;
338 CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
339 sMsg << (CUnsignedSyncCheckpoint)checkpoint;
340 checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
342 if (CSyncCheckpoint::strMasterPrivKey.empty())
343 return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
344 std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
346 key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
347 if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
348 return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
350 if(!checkpoint.ProcessSyncCheckpoint(NULL))
352 printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
359 BOOST_FOREACH(CNode* pnode, vNodes)
360 checkpoint.RelayTo(pnode);
365 // Is the sync-checkpoint outside maturity window?
366 bool IsMatureSyncCheckpoint()
368 LOCK(cs_hashSyncCheckpoint);
369 // sync-checkpoint should always be accepted block
370 assert(mapBlockIndex.count(hashSyncCheckpoint));
371 const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
372 return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
373 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
376 // Is the sync-checkpoint too old?
377 bool IsSyncCheckpointTooOld(unsigned int nSeconds)
379 LOCK(cs_hashSyncCheckpoint);
380 // sync-checkpoint should always be accepted block
381 assert(mapBlockIndex.count(hashSyncCheckpoint));
382 const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
383 return (pindexSync->GetBlockTime() + nSeconds < GetAdjustedTime());
387 // ppcoin: sync-checkpoint master key
388 const std::string CSyncCheckpoint::strMasterPubKey = "04a51b735f816de4ec3f891d5b38bbc91e1f7245c7c08d17990760b86b4d8fc3910a850ffecf73bfa8886f01739a0c4c4322201282d07b6e48ce931cc92af94850";
390 std::string CSyncCheckpoint::strMasterPrivKey = "";
392 // ppcoin: verify signature of sync-checkpoint message
393 bool CSyncCheckpoint::CheckSignature()
396 if (!key.SetPubKey(ParseHex(CSyncCheckpoint::strMasterPubKey)))
397 return error("CSyncCheckpoint::CheckSignature() : SetPubKey failed");
398 if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
399 return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
401 // Now unserialize the data
402 CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
403 sMsg >> *(CUnsignedSyncCheckpoint*)this;
407 // ppcoin: process synchronized checkpoint
408 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
410 if (!CheckSignature())
413 LOCK(Checkpoints::cs_hashSyncCheckpoint);
414 if (!mapBlockIndex.count(hashCheckpoint))
416 // We haven't received the checkpoint chain, keep the checkpoint as pending
417 Checkpoints::hashPendingCheckpoint = hashCheckpoint;
418 Checkpoints::checkpointMessagePending = *this;
419 printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
420 // Ask this guy to fill in what we're missing
423 pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
424 // ask directly as well in case rejected earlier by duplicate
425 // proof-of-stake because getblocks may not get it this time
426 pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
431 if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
435 CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
436 if (!pindexCheckpoint->IsInMainChain())
438 // checkpoint chain received but not yet main chain
440 if (!block.ReadFromDisk(pindexCheckpoint))
441 return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
442 if (!block.SetBestChain(txdb, pindexCheckpoint))
444 Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
445 return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
450 if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
451 return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
452 Checkpoints::checkpointMessage = *this;
453 Checkpoints::hashPendingCheckpoint = 0;
454 Checkpoints::checkpointMessagePending.SetNull();
455 printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());