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 "db.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         return {hashCheckPoint, nTime};
  27     }
  28
  29     //
  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
  33     //    timestamp before)
  34     // + Contains no strange transactions
  35     //
  36     static MapCheckpoints mapCheckpoints =
  37         boost::assign::map_list_of
  38         ( 0, initCheckpoint(hashGenesisBlock, 1360105017) )
  39         ( 6000, initCheckpoint(uint256("0x000000000945e3c9d8e15df834e802521eb79f9ceb4191a27bdfadad4b777f4a"), 1360814368) )
  40         ( 9690, initCheckpoint(uint256("0x00000000026561450859c46868099e0df6068a538f038cb18988fd8d47dcdaf5"), 1362791423) )
  41         ( 13560, initCheckpoint(uint256("0xa1591a0fcbf11f282d671581edb9f0aadcd06fee69761081e0a3245914c13729"), 1364674052) )
  42         ( 14189, initCheckpoint(uint256("0x00000000020f76474d2522b19c7bfafc43ba6ecbabae54293bcd9546159c8c1d"), 1365215020) )
  43         ( 19600, initCheckpoint(uint256("0x252ae08d6df4bc7220c1dcdaed7b8a6e78bab05a60173511e8f565a3a38ce3c3"), 1367840555) )
  44         ( 21800, initCheckpoint(uint256("0x64bdeb35023f240ed01beaa082f840f2d4cc6defccbbcda1260de87e58296b37"), 1368888542) )
  45         ( 26174, initCheckpoint(uint256("0x00000000006cf1bfaa0d73caea92f6d2afa465651a76415b8d53b0bb0e01a8be"), 1371039324) )
  46         ( 27451, initCheckpoint(uint256("0xd65424c24041b9f2e531f8f275f1a3c8bb105f0b29005b0bd577ae1a73341080"), 1371687462) )
  47         ( 37092, initCheckpoint(uint256("0x0000000000a38c2f98556f46793b453e92d8fab2d31c0b93fd08bcf78e56099d"), 1376677203) )
  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         txdb.Close();
 167
 168         Checkpoints::hashSyncCheckpoint = hashCheckpoint;
 169         return true;
 170     }
 171
 172     bool AcceptPendingSyncCheckpoint()
 173     {
 174         LOCK(cs_hashSyncCheckpoint);
 175         if (hashPendingCheckpoint != 0 && mapBlockIndex.count(hashPendingCheckpoint))
 176         {
 177             if (!ValidateSyncCheckpoint(hashPendingCheckpoint))
 178             {
 179                 hashPendingCheckpoint = 0;
 180                 checkpointMessagePending.SetNull();
 181                 return false;
 182             }
 183
 184             CTxDB txdb;
 185             CBlockIndex* pindexCheckpoint = mapBlockIndex[hashPendingCheckpoint];
 186             if (!pindexCheckpoint->IsInMainChain())
 187             {
 188                 CBlock block;
 189                 if (!block.ReadFromDisk(pindexCheckpoint))
 190                     return error("AcceptPendingSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 191                 if (!block.SetBestChain(txdb, pindexCheckpoint))
 192                 {
 193                     hashInvalidCheckpoint = hashPendingCheckpoint;
 194                     return error("AcceptPendingSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 195                 }
 196             }
 197             txdb.Close();
 198
 199             if (!WriteSyncCheckpoint(hashPendingCheckpoint))
 200                 return error("AcceptPendingSyncCheckpoint(): failed to write sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 201             hashPendingCheckpoint = 0;
 202             checkpointMessage = checkpointMessagePending;
 203             checkpointMessagePending.SetNull();
 204             printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
 205             // relay the checkpoint
 206             if (!checkpointMessage.IsNull())
 207             {
 208                 BOOST_FOREACH(CNode* pnode, vNodes)
 209                     checkpointMessage.RelayTo(pnode);
 210             }
 211             return true;
 212         }
 213         return false;
 214     }
 215
 216     // Automatically select a suitable sync-checkpoint
 217     uint256 AutoSelectSyncCheckpoint()
 218     {
 219         // Proof-of-work blocks are immediately checkpointed
 220         // to defend against 51% attack which rejects other miners block
 221
 222         // Select the last proof-of-work block
 223         const CBlockIndex *pindex = GetLastBlockIndex(pindexBest, false);
 224         // Search forward for a block within max span and maturity window
 225         while (pindex->pnext && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN <= pindexBest->GetBlockTime() || pindex->nHeight + std::min(6, nCoinbaseMaturity - 20) <= pindexBest->nHeight))
 226             pindex = pindex->pnext;
 227         return pindex->GetBlockHash();
 228     }
 229
 230     // Check against synchronized checkpoint
 231     bool CheckSync(const uint256& hashBlock, const CBlockIndex* pindexPrev)
 232     {
 233         if (fTestNet) return true; // Testnet has no checkpoints
 234         int nHeight = pindexPrev->nHeight + 1;
 235
 236         LOCK(cs_hashSyncCheckpoint);
 237         // sync-checkpoint should always be accepted block
 238         assert(mapBlockIndex.count(hashSyncCheckpoint));
 239         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 240
 241         if (nHeight > pindexSync->nHeight)
 242         {
 243             // trace back to same height as sync-checkpoint
 244             const CBlockIndex* pindex = pindexPrev;
 245             while (pindex->nHeight > pindexSync->nHeight)
 246                 if (!(pindex = pindex->pprev))
 247                     return error("CheckSync: pprev null - block index structure failure");
 248             if (pindex->nHeight < pindexSync->nHeight || pindex->GetBlockHash() != hashSyncCheckpoint)
 249                 return false; // only descendant of sync-checkpoint can pass check
 250         }
 251         if (nHeight == pindexSync->nHeight && hashBlock != hashSyncCheckpoint)
 252             return false; // same height with sync-checkpoint
 253         if (nHeight < pindexSync->nHeight && !mapBlockIndex.count(hashBlock))
 254             return false; // lower height than sync-checkpoint
 255         return true;
 256     }
 257
 258     bool WantedByPendingSyncCheckpoint(uint256 hashBlock)
 259     {
 260         LOCK(cs_hashSyncCheckpoint);
 261         if (hashPendingCheckpoint == 0)
 262             return false;
 263         if (hashBlock == hashPendingCheckpoint)
 264             return true;
 265         if (mapOrphanBlocks.count(hashPendingCheckpoint)
 266             && hashBlock == WantedByOrphan(mapOrphanBlocks[hashPendingCheckpoint]))
 267             return true;
 268         return false;
 269     }
 270
 271     // ppcoin: reset synchronized checkpoint to last hardened checkpoint
 272     bool ResetSyncCheckpoint()
 273     {
 274         LOCK(cs_hashSyncCheckpoint);
 275         const uint256& hash = mapCheckpoints.rbegin()->second.hashCheckPoint;
 276         if (mapBlockIndex.count(hash) && !mapBlockIndex[hash]->IsInMainChain())
 277         {
 278             // checkpoint block accepted but not yet in main chain
 279             printf("ResetSyncCheckpoint: SetBestChain to hardened checkpoint %s\n", hash.ToString().c_str());
 280             CTxDB txdb;
 281             CBlock block;
 282             if (!block.ReadFromDisk(mapBlockIndex[hash]))
 283                 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
 284             if (!block.SetBestChain(txdb, mapBlockIndex[hash]))
 285             {
 286                 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
 287             }
 288             txdb.Close();
 289         }
 290         else if(!mapBlockIndex.count(hash))
 291         {
 292             // checkpoint block not yet accepted
 293             hashPendingCheckpoint = hash;
 294             checkpointMessagePending.SetNull();
 295             printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
 296         }
 297
 298         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
 299         {
 300             const uint256& hash = i.second.hashCheckPoint;
 301             if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
 302             {
 303                 if (!WriteSyncCheckpoint(hash))
 304                     return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
 305                 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
 306                 return true;
 307             }
 308         }
 309
 310         return false;
 311     }
 312
 313     void AskForPendingSyncCheckpoint(CNode* pfrom)
 314     {
 315         LOCK(cs_hashSyncCheckpoint);
 316         if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
 317             pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
 318     }
 319
 320     bool SetCheckpointPrivKey(std::string strPrivKey)
 321     {
 322         // Test signing a sync-checkpoint with genesis block
 323         CSyncCheckpoint checkpoint;
 324         checkpoint.hashCheckpoint = !fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet;
 325         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 326         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 327         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 328
 329         std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
 330         CKey key;
 331         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 332         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 333             return false;
 334
 335         // Test signing successful, proceed
 336         CSyncCheckpoint::strMasterPrivKey = strPrivKey;
 337         return true;
 338     }
 339
 340     bool SendSyncCheckpoint(uint256 hashCheckpoint)
 341     {
 342         CSyncCheckpoint checkpoint;
 343         checkpoint.hashCheckpoint = hashCheckpoint;
 344         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 345         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 346         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 347
 348         if (CSyncCheckpoint::strMasterPrivKey.empty())
 349             return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
 350         std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
 351         CKey key;
 352         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 353         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 354             return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
 355
 356         if(!checkpoint.ProcessSyncCheckpoint(NULL))
 357         {
 358             printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
 359             return false;
 360         }
 361
 362         // Relay checkpoint
 363         {
 364             LOCK(cs_vNodes);
 365             BOOST_FOREACH(CNode* pnode, vNodes)
 366                 checkpoint.RelayTo(pnode);
 367         }
 368         return true;
 369     }
 370
 371     // Is the sync-checkpoint outside maturity window?
 372     bool IsMatureSyncCheckpoint()
 373     {
 374         LOCK(cs_hashSyncCheckpoint);
 375         // sync-checkpoint should always be accepted block
 376         assert(mapBlockIndex.count(hashSyncCheckpoint));
 377         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 378         return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
 379                 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
 380     }
 381
 382     // Is the sync-checkpoint too old?
 383     bool IsSyncCheckpointTooOld(unsigned int nSeconds)
 384     {
 385         LOCK(cs_hashSyncCheckpoint);
 386         // sync-checkpoint should always be accepted block
 387         assert(mapBlockIndex.count(hashSyncCheckpoint));
 388         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 389         return (pindexSync->GetBlockTime() + nSeconds < GetAdjustedTime());
 390     }
 391 }
 392
 393 // ppcoin: sync-checkpoint master key
 394 const std::string CSyncCheckpoint::strMasterPubKey = "04a51b735f816de4ec3f891d5b38bbc91e1f7245c7c08d17990760b86b4d8fc3910a850ffecf73bfa8886f01739a0c4c4322201282d07b6e48ce931cc92af94850";
 395
 396 std::string CSyncCheckpoint::strMasterPrivKey = "";
 397
 398 // ppcoin: verify signature of sync-checkpoint message
 399 bool CSyncCheckpoint::CheckSignature()
 400 {
 401     CKey key;
 402     if (!key.SetPubKey(ParseHex(CSyncCheckpoint::strMasterPubKey)))
 403         return error("CSyncCheckpoint::CheckSignature() : SetPubKey failed");
 404     if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
 405         return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
 406
 407     // Now unserialize the data
 408     CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
 409     sMsg >> *(CUnsignedSyncCheckpoint*)this;
 410     return true;
 411 }
 412
 413 // ppcoin: process synchronized checkpoint
 414 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
 415 {
 416     if (!CheckSignature())
 417         return false;
 418
 419     LOCK(Checkpoints::cs_hashSyncCheckpoint);
 420     if (!mapBlockIndex.count(hashCheckpoint))
 421     {
 422         // We haven't received the checkpoint chain, keep the checkpoint as pending
 423         Checkpoints::hashPendingCheckpoint = hashCheckpoint;
 424         Checkpoints::checkpointMessagePending = *this;
 425         printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
 426         // Ask this guy to fill in what we're missing
 427         if (pfrom)
 428         {
 429             pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
 430             // ask directly as well in case rejected earlier by duplicate
 431             // proof-of-stake because getblocks may not get it this time
 432             pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
 433         }
 434         return false;
 435     }
 436
 437     if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
 438         return false;
 439
 440     CTxDB txdb;
 441     CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
 442     if (!pindexCheckpoint->IsInMainChain())
 443     {
 444         // checkpoint chain received but not yet main chain
 445         CBlock block;
 446         if (!block.ReadFromDisk(pindexCheckpoint))
 447             return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 448         if (!block.SetBestChain(txdb, pindexCheckpoint))
 449         {
 450             Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
 451             return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 452         }
 453     }
 454     txdb.Close();
 455
 456     if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
 457         return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
 458     Checkpoints::checkpointMessage = *this;
 459     Checkpoints::hashPendingCheckpoint = 0;
 460     Checkpoints::checkpointMessagePending.SetNull();
 461     printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());
 462     return true;
 463 }