src/checkpoints.cpp

   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.
   4
   5 #include <boost/assign/list_of.hpp> // for 'map_list_of()'
   6 #include <boost/foreach.hpp>
   7
   8 #include "checkpoints.h"
   9
  10 #include "txdb.h"
  11 #include "main.h"
  12 #include "uint256.h"
  13
  14 namespace Checkpoints
  15 {
  16     struct Checkpoint
  17     {
  18         uint256 hashCheckPoint;
  19         unsigned int nTime;
  20     };
  21
  22     typedef std::map<int, Checkpoint> MapCheckpoints;
  23
  24     Checkpoint initCheckpoint(uint256 hashCheckPoint, unsigned int nTime)
  25     {
  26         Checkpoint item;
  27         item.hashCheckPoint = hashCheckPoint;
  28         item.nTime = nTime;
  29
  30         return item;
  31     }
  32
  33     //
  34     // What makes a good checkpoint block?
  35     // + Is surrounded by blocks with reasonable timestamps
  36     //   (no blocks before with a timestamp after, none after with
  37     //    timestamp before)
  38     // + Contains no strange transactions
  39     //
  40     static MapCheckpoints mapCheckpoints =
  41         boost::assign::map_list_of
  42         ( 0, initCheckpoint(hashGenesisBlock, 1360105017) )
  43         ( 9690, initCheckpoint(uint256("0x00000000026561450859c46868099e0df6068a538f038cb18988fd8d47dcdaf5"), 1362791423) )
  44         ( 13560, initCheckpoint(uint256("0xa1591a0fcbf11f282d671581edb9f0aadcd06fee69761081e0a3245914c13729"), 1364674052) )
  45         ( 37092, initCheckpoint(uint256("0x0000000000a38c2f98556f46793b453e92d8fab2d31c0b93fd08bcf78e56099d"), 1376677203) )
  46         ( 44200, initCheckpoint(uint256("0xc9bda7232a18b9c1f5ff974a9e5566b2d1879ceb8fc0e9e61fba9038a25b8447"), 1380145962) )
  47     ;
  48
  49     // TestNet has no checkpoints
  50     static MapCheckpoints mapCheckpointsTestnet =
  51         boost::assign::map_list_of
  52         ( 0, initCheckpoint(hashGenesisBlockTestNet, 1360105017) )
  53         ;
  54
  55     bool CheckHardened(int nHeight, const uint256& hash)
  56     {
  57         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  58
  59         MapCheckpoints::const_iterator i = checkpoints.find(nHeight);
  60         if (i == checkpoints.end()) return true;
  61         return hash == i->second.hashCheckPoint;
  62     }
  63
  64     int GetTotalBlocksEstimate()
  65     {
  66         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  67
  68         return checkpoints.rbegin()->first;
  69     }
  70
  71     int GetLastCheckpointTime()
  72     {
  73         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  74
  75         return checkpoints.rbegin()->second.nTime;
  76     }
  77
  78     CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
  79     {
  80         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  81
  82         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, checkpoints)
  83         {
  84             const uint256& hash = i.second.hashCheckPoint;
  85             std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
  86             if (t != mapBlockIndex.end())
  87                 return t->second;
  88         }
  89         return NULL;
  90     }
  91
  92     // ppcoin: synchronized checkpoint (centrally broadcasted)
  93     uint256 hashSyncCheckpoint = 0;
  94     uint256 hashPendingCheckpoint = 0;
  95     CSyncCheckpoint checkpointMessage;
  96     CSyncCheckpoint checkpointMessagePending;
  97     uint256 hashInvalidCheckpoint = 0;
  98     CCriticalSection cs_hashSyncCheckpoint;
  99
 100     // ppcoin: get last synchronized checkpoint
 101     CBlockIndex* GetLastSyncCheckpoint()
 102     {
 103         LOCK(cs_hashSyncCheckpoint);
 104         if (!mapBlockIndex.count(hashSyncCheckpoint))
 105             error("GetSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
 106         else
 107             return mapBlockIndex[hashSyncCheckpoint];
 108         return NULL;
 109     }
 110
 111     // ppcoin: only descendant of current sync-checkpoint is allowed
 112     bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
 113     {
 114         if (!mapBlockIndex.count(hashSyncCheckpoint))
 115             return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
 116         if (!mapBlockIndex.count(hashCheckpoint))
 117             return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
 118
 119         CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
 120         CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
 121
 122         if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
 123         {
 124             // Received an older checkpoint, trace back from current checkpoint
 125             // to the same height of the received checkpoint to verify
 126             // that current checkpoint should be a descendant block
 127             CBlockIndex* pindex = pindexSyncCheckpoint;
 128             while (pindex->nHeight > pindexCheckpointRecv->nHeight)
 129                 if (!(pindex = pindex->pprev))
 130                     return error("ValidateSyncCheckpoint: pprev1 null - block index structure failure");
 131             if (pindex->GetBlockHash() != hashCheckpoint)
 132             {
 133                 hashInvalidCheckpoint = hashCheckpoint;
 134                 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is conflicting with current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 135             }
 136             return false; // ignore older checkpoint
 137         }
 138
 139         // Received checkpoint should be a descendant block of the current
 140         // checkpoint. Trace back to the same height of current checkpoint
 141         // to verify.
 142         CBlockIndex* pindex = pindexCheckpointRecv;
 143         while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
 144             if (!(pindex = pindex->pprev))
 145                 return error("ValidateSyncCheckpoint: pprev2 null - block index structure failure");
 146         if (pindex->GetBlockHash() != hashSyncCheckpoint)
 147         {
 148             hashInvalidCheckpoint = hashCheckpoint;
 149             return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 150         }
 151         return true;
 152     }
 153
 154     bool WriteSyncCheckpoint(const uint256& hashCheckpoint)
 155     {
 156         CTxDB txdb;
 157         txdb.TxnBegin();
 158         if (!txdb.WriteSyncCheckpoint(hashCheckpoint))
 159         {
 160             txdb.TxnAbort();
 161             return error("WriteSyncCheckpoint(): failed to write to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 162         }
 163         if (!txdb.TxnCommit())
 164             return error("WriteSyncCheckpoint(): failed to commit to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 165
 166 #ifndef USE_LEVELDB
 167         txdb.Close();
 168 #endif
 169
 170         Checkpoints::hashSyncCheckpoint = hashCheckpoint;
 171         return true;
 172     }
 173
 174     bool AcceptPendingSyncCheckpoint()
 175     {
 176         LOCK(cs_hashSyncCheckpoint);
 177         if (hashPendingCheckpoint != 0 && mapBlockIndex.count(hashPendingCheckpoint))
 178         {
 179             if (!ValidateSyncCheckpoint(hashPendingCheckpoint))
 180             {
 181                 hashPendingCheckpoint = 0;
 182                 checkpointMessagePending.SetNull();
 183                 return false;
 184             }
 185
 186             CTxDB txdb;
 187             CBlockIndex* pindexCheckpoint = mapBlockIndex[hashPendingCheckpoint];
 188             if (!pindexCheckpoint->IsInMainChain())
 189             {
 190                 CBlock block;
 191                 if (!block.ReadFromDisk(pindexCheckpoint))
 192                     return error("AcceptPendingSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 193                 if (!block.SetBestChain(txdb, pindexCheckpoint))
 194                 {
 195                     hashInvalidCheckpoint = hashPendingCheckpoint;
 196                     return error("AcceptPendingSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 197                 }
 198             }
 199
 200 #ifndef USE_LEVELDB
 201             txdb.Close();
 202 #endif
 203             if (!WriteSyncCheckpoint(hashPendingCheckpoint))
 204                 return error("AcceptPendingSyncCheckpoint(): failed to write sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 205             hashPendingCheckpoint = 0;
 206             checkpointMessage = checkpointMessagePending;
 207             checkpointMessagePending.SetNull();
 208             printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
 209             // relay the checkpoint
 210             if (!checkpointMessage.IsNull())
 211             {
 212                 BOOST_FOREACH(CNode* pnode, vNodes)
 213                     checkpointMessage.RelayTo(pnode);
 214             }
 215             return true;
 216         }
 217         return false;
 218     }
 219
 220     // Automatically select a suitable sync-checkpoint
 221     uint256 AutoSelectSyncCheckpoint()
 222     {
 223         // Proof-of-work blocks are immediately checkpointed
 224         // to defend against 51% attack which rejects other miners block
 225
 226         // Select the last proof-of-work block
 227         const CBlockIndex *pindex = GetLastBlockIndex(pindexBest, false);
 228         // Search forward for a block within max span and maturity window
 229         while (pindex->pnext && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN <= pindexBest->GetBlockTime() || pindex->nHeight + std::min(6, nCoinbaseMaturity - 20) <= pindexBest->nHeight))
 230             pindex = pindex->pnext;
 231         return pindex->GetBlockHash();
 232     }
 233
 234     // Check against synchronized checkpoint
 235     bool CheckSync(const uint256& hashBlock, const CBlockIndex* pindexPrev)
 236     {
 237         if (fTestNet) return true; // Testnet has no checkpoints
 238         int nHeight = pindexPrev->nHeight + 1;
 239
 240         LOCK(cs_hashSyncCheckpoint);
 241         // sync-checkpoint should always be accepted block
 242         assert(mapBlockIndex.count(hashSyncCheckpoint));
 243         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 244
 245         if (nHeight > pindexSync->nHeight)
 246         {
 247             // trace back to same height as sync-checkpoint
 248             const CBlockIndex* pindex = pindexPrev;
 249             while (pindex->nHeight > pindexSync->nHeight)
 250                 if (!(pindex = pindex->pprev))
 251                     return error("CheckSync: pprev null - block index structure failure");
 252             if (pindex->nHeight < pindexSync->nHeight || pindex->GetBlockHash() != hashSyncCheckpoint)
 253                 return false; // only descendant of sync-checkpoint can pass check
 254         }
 255         if (nHeight == pindexSync->nHeight && hashBlock != hashSyncCheckpoint)
 256             return false; // same height with sync-checkpoint
 257         if (nHeight < pindexSync->nHeight && !mapBlockIndex.count(hashBlock))
 258             return false; // lower height than sync-checkpoint
 259         return true;
 260     }
 261
 262     bool WantedByPendingSyncCheckpoint(uint256 hashBlock)
 263     {
 264         LOCK(cs_hashSyncCheckpoint);
 265         if (hashPendingCheckpoint == 0)
 266             return false;
 267         if (hashBlock == hashPendingCheckpoint)
 268             return true;
 269         if (mapOrphanBlocks.count(hashPendingCheckpoint)
 270             && hashBlock == WantedByOrphan(mapOrphanBlocks[hashPendingCheckpoint]))
 271             return true;
 272         return false;
 273     }
 274
 275     // ppcoin: reset synchronized checkpoint to last hardened checkpoint
 276     bool ResetSyncCheckpoint()
 277     {
 278         LOCK(cs_hashSyncCheckpoint);
 279         const uint256& hash = mapCheckpoints.rbegin()->second.hashCheckPoint;
 280         if (mapBlockIndex.count(hash) && !mapBlockIndex[hash]->IsInMainChain())
 281         {
 282             // checkpoint block accepted but not yet in main chain
 283             printf("ResetSyncCheckpoint: SetBestChain to hardened checkpoint %s\n", hash.ToString().c_str());
 284             CTxDB txdb;
 285             CBlock block;
 286             if (!block.ReadFromDisk(mapBlockIndex[hash]))
 287                 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
 288             if (!block.SetBestChain(txdb, mapBlockIndex[hash]))
 289             {
 290                 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
 291             }
 292
 293 #ifndef USE_LEVELDB
 294             txdb.Close();
 295 #endif
 296
 297         }
 298         else if(!mapBlockIndex.count(hash))
 299         {
 300             // checkpoint block not yet accepted
 301             hashPendingCheckpoint = hash;
 302             checkpointMessagePending.SetNull();
 303             printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
 304         }
 305
 306         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
 307         {
 308             const uint256& hash = i.second.hashCheckPoint;
 309             if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
 310             {
 311                 if (!WriteSyncCheckpoint(hash))
 312                     return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
 313                 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
 314                 return true;
 315             }
 316         }
 317
 318         return false;
 319     }
 320
 321     void AskForPendingSyncCheckpoint(CNode* pfrom)
 322     {
 323         LOCK(cs_hashSyncCheckpoint);
 324         if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
 325             pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
 326     }
 327
 328     bool SetCheckpointPrivKey(std::string strPrivKey)
 329     {
 330         // Test signing a sync-checkpoint with genesis block
 331         CSyncCheckpoint checkpoint;
 332         checkpoint.hashCheckpoint = !fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet;
 333         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 334         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 335         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 336
 337         std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
 338         CKey key;
 339         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 340         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 341             return false;
 342
 343         // Test signing successful, proceed
 344         CSyncCheckpoint::strMasterPrivKey = strPrivKey;
 345         return true;
 346     }
 347
 348     bool SendSyncCheckpoint(uint256 hashCheckpoint)
 349     {
 350         CSyncCheckpoint checkpoint;
 351         checkpoint.hashCheckpoint = hashCheckpoint;
 352         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 353         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 354         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 355
 356         if (CSyncCheckpoint::strMasterPrivKey.empty())
 357             return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
 358         std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
 359         CKey key;
 360         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 361         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 362             return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
 363
 364         if(!checkpoint.ProcessSyncCheckpoint(NULL))
 365         {
 366             printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
 367             return false;
 368         }
 369
 370         // Relay checkpoint
 371         {
 372             LOCK(cs_vNodes);
 373             BOOST_FOREACH(CNode* pnode, vNodes)
 374                 checkpoint.RelayTo(pnode);
 375         }
 376         return true;
 377     }
 378
 379     // Is the sync-checkpoint outside maturity window?
 380     bool IsMatureSyncCheckpoint()
 381     {
 382         LOCK(cs_hashSyncCheckpoint);
 383         // sync-checkpoint should always be accepted block
 384         assert(mapBlockIndex.count(hashSyncCheckpoint));
 385         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 386         return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
 387                 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
 388     }
 389
 390     // Is the sync-checkpoint too old?
 391     bool IsSyncCheckpointTooOld(unsigned int nSeconds)
 392     {
 393         LOCK(cs_hashSyncCheckpoint);
 394         // sync-checkpoint should always be accepted block
 395         assert(mapBlockIndex.count(hashSyncCheckpoint));
 396         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 397         return (pindexSync->GetBlockTime() + nSeconds < GetAdjustedTime());
 398     }
 399 }
 400
 401 // ppcoin: sync-checkpoint master key
 402 const std::string CSyncCheckpoint::strMasterPubKey = "04a51b735f816de4ec3f891d5b38bbc91e1f7245c7c08d17990760b86b4d8fc3910a850ffecf73bfa8886f01739a0c4c4322201282d07b6e48ce931cc92af94850";
 403
 404 std::string CSyncCheckpoint::strMasterPrivKey = "";
 405
 406 // ppcoin: verify signature of sync-checkpoint message
 407 bool CSyncCheckpoint::CheckSignature()
 408 {
 409     CKey key;
 410     if (!key.SetPubKey(ParseHex(CSyncCheckpoint::strMasterPubKey)))
 411         return error("CSyncCheckpoint::CheckSignature() : SetPubKey failed");
 412     if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
 413         return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
 414
 415     // Now unserialize the data
 416     CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
 417     sMsg >> *(CUnsignedSyncCheckpoint*)this;
 418     return true;
 419 }
 420
 421 // ppcoin: process synchronized checkpoint
 422 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
 423 {
 424     if (!CheckSignature())
 425         return false;
 426
 427     LOCK(Checkpoints::cs_hashSyncCheckpoint);
 428     if (!mapBlockIndex.count(hashCheckpoint))
 429     {
 430         // We haven't received the checkpoint chain, keep the checkpoint as pending
 431         Checkpoints::hashPendingCheckpoint = hashCheckpoint;
 432         Checkpoints::checkpointMessagePending = *this;
 433         printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
 434         // Ask this guy to fill in what we're missing
 435         if (pfrom)
 436         {
 437             pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
 438             // ask directly as well in case rejected earlier by duplicate
 439             // proof-of-stake because getblocks may not get it this time
 440             pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
 441         }
 442         return false;
 443     }
 444
 445     if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
 446         return false;
 447
 448     CTxDB txdb;
 449     CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
 450     if (!pindexCheckpoint->IsInMainChain())
 451     {
 452         // checkpoint chain received but not yet main chain
 453         CBlock block;
 454         if (!block.ReadFromDisk(pindexCheckpoint))
 455             return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 456         if (!block.SetBestChain(txdb, pindexCheckpoint))
 457         {
 458             Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
 459             return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 460         }
 461     }
 462
 463 #ifndef USE_LEVELDB
 464     txdb.Close();
 465 #endif
 466
 467     if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
 468         return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
 469     Checkpoints::checkpointMessage = *this;
 470     Checkpoints::hashPendingCheckpoint = 0;
 471     Checkpoints::checkpointMessagePending.SetNull();
 472     printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());
 473     return true;
 474 }