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         ( 65000, initCheckpoint(uint256("0xfb2b51a2fd65062c98a7a6053cde46aeaefebb95ba2f680e85a29ee25b1dcf05"), 1388526385) )
  48     ;
  49
  50     // TestNet has no checkpoints
  51     static MapCheckpoints mapCheckpointsTestnet =
  52         boost::assign::map_list_of
  53         ( 0, initCheckpoint(hashGenesisBlockTestNet, 1360105017) )
  54         ;
  55
  56     bool CheckHardened(int nHeight, const uint256& hash)
  57     {
  58         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  59
  60         MapCheckpoints::const_iterator i = checkpoints.find(nHeight);
  61         if (i == checkpoints.end()) return true;
  62         return hash == i->second.hashCheckPoint;
  63     }
  64
  65     int GetTotalBlocksEstimate()
  66     {
  67         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  68
  69         return checkpoints.rbegin()->first;
  70     }
  71
  72     int GetLastCheckpointTime()
  73     {
  74         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  75
  76         return checkpoints.rbegin()->second.nTime;
  77     }
  78
  79     CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
  80     {
  81         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  82
  83         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, checkpoints)
  84         {
  85             const uint256& hash = i.second.hashCheckPoint;
  86             std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
  87             if (t != mapBlockIndex.end())
  88                 return t->second;
  89         }
  90         return NULL;
  91     }
  92
  93     // ppcoin: synchronized checkpoint (centrally broadcasted)
  94     uint256 hashSyncCheckpoint = 0;
  95     uint256 hashPendingCheckpoint = 0;
  96     CSyncCheckpoint checkpointMessage;
  97     CSyncCheckpoint checkpointMessagePending;
  98     uint256 hashInvalidCheckpoint = 0;
  99     CCriticalSection cs_hashSyncCheckpoint;
 100
 101     // ppcoin: get last synchronized checkpoint
 102     CBlockIndex* GetLastSyncCheckpoint()
 103     {
 104         LOCK(cs_hashSyncCheckpoint);
 105         if (!mapBlockIndex.count(hashSyncCheckpoint))
 106             error("GetSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
 107         else
 108             return mapBlockIndex[hashSyncCheckpoint];
 109         return NULL;
 110     }
 111
 112     // ppcoin: only descendant of current sync-checkpoint is allowed
 113     bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
 114     {
 115         if (!mapBlockIndex.count(hashSyncCheckpoint))
 116             return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
 117         if (!mapBlockIndex.count(hashCheckpoint))
 118             return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
 119
 120         CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
 121         CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
 122
 123         if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
 124         {
 125             // Received an older checkpoint, trace back from current checkpoint
 126             // to the same height of the received checkpoint to verify
 127             // that current checkpoint should be a descendant block
 128             CBlockIndex* pindex = pindexSyncCheckpoint;
 129             while (pindex->nHeight > pindexCheckpointRecv->nHeight)
 130                 if (!(pindex = pindex->pprev))
 131                     return error("ValidateSyncCheckpoint: pprev1 null - block index structure failure");
 132             if (pindex->GetBlockHash() != hashCheckpoint)
 133             {
 134                 hashInvalidCheckpoint = hashCheckpoint;
 135                 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is conflicting with current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 136             }
 137             return false; // ignore older checkpoint
 138         }
 139
 140         // Received checkpoint should be a descendant block of the current
 141         // checkpoint. Trace back to the same height of current checkpoint
 142         // to verify.
 143         CBlockIndex* pindex = pindexCheckpointRecv;
 144         while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
 145             if (!(pindex = pindex->pprev))
 146                 return error("ValidateSyncCheckpoint: pprev2 null - block index structure failure");
 147         if (pindex->GetBlockHash() != hashSyncCheckpoint)
 148         {
 149             hashInvalidCheckpoint = hashCheckpoint;
 150             return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 151         }
 152         return true;
 153     }
 154
 155     bool WriteSyncCheckpoint(const uint256& hashCheckpoint)
 156     {
 157         CTxDB txdb;
 158         txdb.TxnBegin();
 159         if (!txdb.WriteSyncCheckpoint(hashCheckpoint))
 160         {
 161             txdb.TxnAbort();
 162             return error("WriteSyncCheckpoint(): failed to write to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 163         }
 164         if (!txdb.TxnCommit())
 165             return error("WriteSyncCheckpoint(): failed to commit to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 166
 167 #ifndef USE_LEVELDB
 168         txdb.Close();
 169 #endif
 170
 171         Checkpoints::hashSyncCheckpoint = hashCheckpoint;
 172         return true;
 173     }
 174
 175     bool AcceptPendingSyncCheckpoint()
 176     {
 177         LOCK(cs_hashSyncCheckpoint);
 178         if (hashPendingCheckpoint != 0 && mapBlockIndex.count(hashPendingCheckpoint))
 179         {
 180             if (!ValidateSyncCheckpoint(hashPendingCheckpoint))
 181             {
 182                 hashPendingCheckpoint = 0;
 183                 checkpointMessagePending.SetNull();
 184                 return false;
 185             }
 186
 187             CTxDB txdb;
 188             CBlockIndex* pindexCheckpoint = mapBlockIndex[hashPendingCheckpoint];
 189             if (!pindexCheckpoint->IsInMainChain())
 190             {
 191                 CBlock block;
 192                 if (!block.ReadFromDisk(pindexCheckpoint))
 193                     return error("AcceptPendingSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 194                 if (!block.SetBestChain(txdb, pindexCheckpoint))
 195                 {
 196                     hashInvalidCheckpoint = hashPendingCheckpoint;
 197                     return error("AcceptPendingSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 198                 }
 199             }
 200
 201 #ifndef USE_LEVELDB
 202             txdb.Close();
 203 #endif
 204             if (!WriteSyncCheckpoint(hashPendingCheckpoint))
 205                 return error("AcceptPendingSyncCheckpoint(): failed to write sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 206             hashPendingCheckpoint = 0;
 207             checkpointMessage = checkpointMessagePending;
 208             checkpointMessagePending.SetNull();
 209             printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
 210             // relay the checkpoint
 211             if (!checkpointMessage.IsNull())
 212             {
 213                 BOOST_FOREACH(CNode* pnode, vNodes)
 214                     checkpointMessage.RelayTo(pnode);
 215             }
 216             return true;
 217         }
 218         return false;
 219     }
 220
 221     // Automatically select a suitable sync-checkpoint
 222     uint256 AutoSelectSyncCheckpoint()
 223     {
 224         // Proof-of-work blocks are immediately checkpointed
 225         // to defend against 51% attack which rejects other miners block
 226
 227         // Select the last proof-of-work block
 228         const CBlockIndex *pindex = GetLastBlockIndex(pindexBest, false);
 229         // Search forward for a block within max span and maturity window
 230         while (pindex->pnext && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN <= pindexBest->GetBlockTime() || pindex->nHeight + std::min(6, nCoinbaseMaturity - 20) <= pindexBest->nHeight))
 231             pindex = pindex->pnext;
 232         return pindex->GetBlockHash();
 233     }
 234
 235     // Check against synchronized checkpoint
 236     bool CheckSync(const uint256& hashBlock, const CBlockIndex* pindexPrev)
 237     {
 238         if (fTestNet) return true; // Testnet has no checkpoints
 239         int nHeight = pindexPrev->nHeight + 1;
 240
 241         LOCK(cs_hashSyncCheckpoint);
 242         // sync-checkpoint should always be accepted block
 243         assert(mapBlockIndex.count(hashSyncCheckpoint));
 244         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 245
 246         if (nHeight > pindexSync->nHeight)
 247         {
 248             // trace back to same height as sync-checkpoint
 249             const CBlockIndex* pindex = pindexPrev;
 250             while (pindex->nHeight > pindexSync->nHeight)
 251                 if (!(pindex = pindex->pprev))
 252                     return error("CheckSync: pprev null - block index structure failure");
 253             if (pindex->nHeight < pindexSync->nHeight || pindex->GetBlockHash() != hashSyncCheckpoint)
 254                 return false; // only descendant of sync-checkpoint can pass check
 255         }
 256         if (nHeight == pindexSync->nHeight && hashBlock != hashSyncCheckpoint)
 257             return false; // same height with sync-checkpoint
 258         if (nHeight < pindexSync->nHeight && !mapBlockIndex.count(hashBlock))
 259             return false; // lower height than sync-checkpoint
 260         return true;
 261     }
 262
 263     bool WantedByPendingSyncCheckpoint(uint256 hashBlock)
 264     {
 265         LOCK(cs_hashSyncCheckpoint);
 266         if (hashPendingCheckpoint == 0)
 267             return false;
 268         if (hashBlock == hashPendingCheckpoint)
 269             return true;
 270         if (mapOrphanBlocks.count(hashPendingCheckpoint)
 271             && hashBlock == WantedByOrphan(mapOrphanBlocks[hashPendingCheckpoint]))
 272             return true;
 273         return false;
 274     }
 275
 276     // ppcoin: reset synchronized checkpoint to last hardened checkpoint
 277     bool ResetSyncCheckpoint()
 278     {
 279         LOCK(cs_hashSyncCheckpoint);
 280         const uint256& hash = mapCheckpoints.rbegin()->second.hashCheckPoint;
 281         if (mapBlockIndex.count(hash) && !mapBlockIndex[hash]->IsInMainChain())
 282         {
 283             // checkpoint block accepted but not yet in main chain
 284             printf("ResetSyncCheckpoint: SetBestChain to hardened checkpoint %s\n", hash.ToString().c_str());
 285             CTxDB txdb;
 286             CBlock block;
 287             if (!block.ReadFromDisk(mapBlockIndex[hash]))
 288                 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
 289             if (!block.SetBestChain(txdb, mapBlockIndex[hash]))
 290             {
 291                 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
 292             }
 293
 294 #ifndef USE_LEVELDB
 295             txdb.Close();
 296 #endif
 297
 298         }
 299         else if(!mapBlockIndex.count(hash))
 300         {
 301             // checkpoint block not yet accepted
 302             hashPendingCheckpoint = hash;
 303             checkpointMessagePending.SetNull();
 304             printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
 305         }
 306
 307         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
 308         {
 309             const uint256& hash = i.second.hashCheckPoint;
 310             if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
 311             {
 312                 if (!WriteSyncCheckpoint(hash))
 313                     return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
 314                 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
 315                 return true;
 316             }
 317         }
 318
 319         return false;
 320     }
 321
 322     void AskForPendingSyncCheckpoint(CNode* pfrom)
 323     {
 324         LOCK(cs_hashSyncCheckpoint);
 325         if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
 326             pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
 327     }
 328
 329     bool SetCheckpointPrivKey(std::string strPrivKey)
 330     {
 331         // Test signing a sync-checkpoint with genesis block
 332         CSyncCheckpoint checkpoint;
 333         checkpoint.hashCheckpoint = !fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet;
 334         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 335         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 336         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 337
 338         std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
 339         CKey key;
 340         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 341         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 342             return false;
 343
 344         // Test signing successful, proceed
 345         CSyncCheckpoint::strMasterPrivKey = strPrivKey;
 346         return true;
 347     }
 348
 349     bool SendSyncCheckpoint(uint256 hashCheckpoint)
 350     {
 351         CSyncCheckpoint checkpoint;
 352         checkpoint.hashCheckpoint = hashCheckpoint;
 353         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 354         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 355         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 356
 357         if (CSyncCheckpoint::strMasterPrivKey.empty())
 358             return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
 359         std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
 360         CKey key;
 361         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 362         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 363             return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
 364
 365         if(!checkpoint.ProcessSyncCheckpoint(NULL))
 366         {
 367             printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
 368             return false;
 369         }
 370
 371         // Relay checkpoint
 372         {
 373             LOCK(cs_vNodes);
 374             BOOST_FOREACH(CNode* pnode, vNodes)
 375                 checkpoint.RelayTo(pnode);
 376         }
 377         return true;
 378     }
 379
 380     // Is the sync-checkpoint outside maturity window?
 381     bool IsMatureSyncCheckpoint()
 382     {
 383         LOCK(cs_hashSyncCheckpoint);
 384         // sync-checkpoint should always be accepted block
 385         assert(mapBlockIndex.count(hashSyncCheckpoint));
 386         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 387         return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
 388                 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
 389     }
 390
 391     // Is the sync-checkpoint too old?
 392     bool IsSyncCheckpointTooOld(unsigned int nSeconds)
 393     {
 394         LOCK(cs_hashSyncCheckpoint);
 395         // sync-checkpoint should always be accepted block
 396         assert(mapBlockIndex.count(hashSyncCheckpoint));
 397         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 398         return (pindexSync->GetBlockTime() + nSeconds < GetAdjustedTime());
 399     }
 400 }
 401
 402 // ppcoin: sync-checkpoint master key
 403 const std::string CSyncCheckpoint::strMasterPubKey = "04a51b735f816de4ec3f891d5b38bbc91e1f7245c7c08d17990760b86b4d8fc3910a850ffecf73bfa8886f01739a0c4c4322201282d07b6e48ce931cc92af94850";
 404
 405 std::string CSyncCheckpoint::strMasterPrivKey = "";
 406
 407 // ppcoin: verify signature of sync-checkpoint message
 408 bool CSyncCheckpoint::CheckSignature()
 409 {
 410     CKey key;
 411     if (!key.SetPubKey(ParseHex(CSyncCheckpoint::strMasterPubKey)))
 412         return error("CSyncCheckpoint::CheckSignature() : SetPubKey failed");
 413     if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
 414         return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
 415
 416     // Now unserialize the data
 417     CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
 418     sMsg >> *(CUnsignedSyncCheckpoint*)this;
 419     return true;
 420 }
 421
 422 // ppcoin: process synchronized checkpoint
 423 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
 424 {
 425     if (!CheckSignature())
 426         return false;
 427
 428     LOCK(Checkpoints::cs_hashSyncCheckpoint);
 429     if (!mapBlockIndex.count(hashCheckpoint))
 430     {
 431         // We haven't received the checkpoint chain, keep the checkpoint as pending
 432         Checkpoints::hashPendingCheckpoint = hashCheckpoint;
 433         Checkpoints::checkpointMessagePending = *this;
 434         printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
 435         // Ask this guy to fill in what we're missing
 436         if (pfrom)
 437         {
 438             pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
 439             // ask directly as well in case rejected earlier by duplicate
 440             // proof-of-stake because getblocks may not get it this time
 441             pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
 442         }
 443         return false;
 444     }
 445
 446     if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
 447         return false;
 448
 449     CTxDB txdb;
 450     CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
 451     if (!pindexCheckpoint->IsInMainChain())
 452     {
 453         // checkpoint chain received but not yet main chain
 454         CBlock block;
 455         if (!block.ReadFromDisk(pindexCheckpoint))
 456             return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 457         if (!block.SetBestChain(txdb, pindexCheckpoint))
 458         {
 459             Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
 460             return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 461         }
 462     }
 463
 464 #ifndef USE_LEVELDB
 465     txdb.Close();
 466 #endif
 467
 468     if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
 469         return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
 470     Checkpoints::checkpointMessage = *this;
 471     Checkpoints::hashPendingCheckpoint = 0;
 472     Checkpoints::checkpointMessagePending.SetNull();
 473     printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());
 474     return true;
 475 }