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