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 "checkpoints.h"
   6 #include "main.h"
   7 #include "txdb-leveldb.h"
   8 #include "uint256.h"
   9
  10 #include <algorithm>
  11
  12
  13 namespace Checkpoints
  14 {
  15     typedef std::map<int, std::pair<uint256, unsigned int> > MapCheckpoints;
  16     typedef std::list<uint256> ListBannedBlocks;
  17
  18     //
  19     // What makes a good checkpoint block?
  20     // + Is surrounded by blocks with reasonable timestamps
  21     //   (no blocks before with a timestamp after, none after with
  22     //    timestamp before)
  23     // + Contains no strange transactions
  24     //
  25     static MapCheckpoints mapCheckpoints =
  26     {
  27         { 0,      {hashGenesisBlock, 1360105017} },
  28         { 13560,  {uint256("0xa1591a0fcbf11f282d671581edb9f0aadcd06fee69761081e0a3245914c13729"), 1364674052} },
  29         { 143990, {uint256("0x00000000001ff5c3940a9f73ad4a990f64955179bde0f743c76dbf0031429efc"), 1418953493} },
  30         { 149000, {uint256("0x7a24acfcadcf43054e7f7d9f273522c0dfc5791ba4006e0273e7521a8d36c525"), 1420872125} },
  31         { 160000, {uint256("0x000000000001cb1133043d38d077c0e93f66c8b2566779f10f182137d1e34a68"), 1425150237} },
  32         { 200000, {uint256("0x0000000000029f8bbf66e6ea6f3e5db55009404aae0fe395a53dd33142b2bff2"), 1441127233} },
  33         { 221047, {uint256("0xa28aef712e7aa0c285bfe29351ca21ed416689139e3063ef770fc826a8b9e9da"), 1449431646} },
  34         { 243100, {uint256("0x000000000006522d1ebc0734cb0e6b83f5d4da0c3cbc72bd91b82016f611c4f0"), 1458215793} },
  35         { 532000, {uint256("0x0000000000018b7eba5e189c41605780c8a855f74144fa837fa05fa4c67b6ba9"), 1569359486} },
  36         { 561108, {uint256("0x2f3cf523ae1022300b4f40073e506d15ef0d6e208f123aed5b93016f81a10e1e"), 1580943827} },
  37         { 712891, {uint256("0xaaafebcb23c1b8ab49f7517b7a34bcc420cc6f284d9ffc672c1f47b5af2b0088"), 1640557462} }
  38     };
  39
  40     static ListBannedBlocks listBanned =
  41     {
  42         // Invalid block #221047 with future timestamp of 2016/02/23 09:24:17 UTC
  43         uint256("0x46223e5432ceffe650d5729b4bb8479dcdf0ca1e534fa8e69382dc87b42ea94b")
  44     };
  45
  46     // TestNet has no checkpoints
  47     static MapCheckpoints mapCheckpointsTestnet =
  48     {
  49         { 0, { hashGenesisBlockTestNet, 1360105017 } }
  50     };
  51
  52     bool CheckHardened(int nHeight, const uint256& hash)
  53     {
  54         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  55
  56         MapCheckpoints::const_iterator i = checkpoints.find(nHeight);
  57         if (i == checkpoints.end()) return true;
  58         return hash == i->second.first;
  59     }
  60
  61     bool CheckBanned(const uint256 &nHash)
  62     {
  63         if (fTestNet) // Testnet has no banned blocks
  64             return true;
  65         ListBannedBlocks::const_iterator it = std::find(listBanned.begin(), listBanned.end(), nHash);
  66         return it == listBanned.end();
  67     }
  68
  69     int GetTotalBlocksEstimate()
  70     {
  71         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  72
  73         return checkpoints.rbegin()->first;
  74     }
  75
  76     unsigned int GetLastCheckpointTime()
  77     {
  78         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  79
  80         return checkpoints.rbegin()->second.second;
  81     }
  82
  83     CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
  84     {
  85         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  86
  87         for(auto it = checkpoints.rbegin(); it != checkpoints.rend(); ++it)
  88         {
  89             const uint256& hash = it->second.first;
  90             auto t = mapBlockIndex.find(hash);
  91             if (t != mapBlockIndex.end())
  92                 return t->second;
  93         }
  94         return NULL;
  95     }
  96
  97     // ppcoin: synchronized checkpoint (centrally broadcasted)
  98     uint256 hashSyncCheckpoint = 0;
  99     uint256 hashPendingCheckpoint = 0;
 100     CSyncCheckpoint checkpointMessage;
 101     CSyncCheckpoint checkpointMessagePending;
 102     uint256 hashInvalidCheckpoint = 0;
 103     CCriticalSection cs_hashSyncCheckpoint;
 104
 105     // ppcoin: get last synchronized checkpoint
 106     CBlockIndex* GetLastSyncCheckpoint()
 107     {
 108         LOCK(cs_hashSyncCheckpoint);
 109         if (!mapBlockIndex.count(hashSyncCheckpoint))
 110             error("GetSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
 111         else
 112             return mapBlockIndex[hashSyncCheckpoint];
 113         return NULL;
 114     }
 115
 116     // ppcoin: only descendant of current sync-checkpoint is allowed
 117     bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
 118     {
 119         if (!mapBlockIndex.count(hashSyncCheckpoint))
 120             return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
 121         if (!mapBlockIndex.count(hashCheckpoint))
 122             return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
 123
 124         CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
 125         CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
 126
 127         if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
 128         {
 129             // Received an older checkpoint, trace back from current checkpoint
 130             // to the same height of the received checkpoint to verify
 131             // that current checkpoint should be a descendant block
 132             CBlockIndex* pindex = pindexSyncCheckpoint;
 133             while (pindex->nHeight > pindexCheckpointRecv->nHeight)
 134                 if ((pindex = pindex->pprev) == NULL)
 135                     return error("ValidateSyncCheckpoint: pprev null - block index structure failure");
 136             if (pindex->GetBlockHash() != hashCheckpoint)
 137             {
 138                 hashInvalidCheckpoint = hashCheckpoint;
 139                 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is conflicting with current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 140             }
 141             return false; // ignore older checkpoint
 142         }
 143
 144         // Received checkpoint should be a descendant block of the current
 145         // checkpoint. Trace back to the same height of current checkpoint
 146         // to verify.
 147         CBlockIndex* pindex = pindexCheckpointRecv;
 148         while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
 149             if ((pindex = pindex->pprev) == NULL)
 150                 return error("ValidateSyncCheckpoint: pprev2 null - block index structure failure");
 151         if (pindex->GetBlockHash() != hashSyncCheckpoint)
 152         {
 153             hashInvalidCheckpoint = hashCheckpoint;
 154             return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 155         }
 156         return true;
 157     }
 158
 159     bool WriteSyncCheckpoint(const uint256& hashCheckpoint)
 160     {
 161         CTxDB txdb;
 162         txdb.TxnBegin();
 163         if (!txdb.WriteSyncCheckpoint(hashCheckpoint))
 164         {
 165             txdb.TxnAbort();
 166             return error("WriteSyncCheckpoint(): failed to write to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 167         }
 168         if (!txdb.TxnCommit())
 169             return error("WriteSyncCheckpoint(): failed to commit to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 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             if (!WriteSyncCheckpoint(hashPendingCheckpoint))
 202                 return error("AcceptPendingSyncCheckpoint(): failed to write sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 203             hashPendingCheckpoint = 0;
 204             checkpointMessage = checkpointMessagePending;
 205             checkpointMessagePending.SetNull();
 206             printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
 207             // relay the checkpoint
 208             if (!checkpointMessage.IsNull())
 209             {
 210                 for (std::vector<CNode*>::iterator it = vNodes.begin(); it != vNodes.end(); ++it)
 211                     checkpointMessage.RelayTo(*it);
 212             }
 213             return true;
 214         }
 215         return false;
 216     }
 217
 218     // Automatically select a suitable sync-checkpoint
 219     uint256 AutoSelectSyncCheckpoint()
 220     {
 221         const CBlockIndex *pindex = pindexBest;
 222         // Search backward for a block within max span and maturity window
 223         while (pindex->pprev && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN > pindexBest->GetBlockTime() || pindex->nHeight + 8 > pindexBest->nHeight))
 224             pindex = pindex->pprev;
 225         return pindex->GetBlockHash();
 226     }
 227
 228     // Check against synchronized checkpoint
 229     bool CheckSync(const uint256& hashBlock, const CBlockIndex* pindexPrev)
 230     {
 231         if (fTestNet) return true; // Testnet has no checkpoints
 232         int nHeight = pindexPrev->nHeight + 1;
 233
 234         LOCK(cs_hashSyncCheckpoint);
 235         // sync-checkpoint should always be accepted block
 236         assert(mapBlockIndex.count(hashSyncCheckpoint));
 237         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 238
 239         if (nHeight > pindexSync->nHeight)
 240         {
 241             // trace back to same height as sync-checkpoint
 242             const CBlockIndex* pindex = pindexPrev;
 243             while (pindex->nHeight > pindexSync->nHeight)
 244                 if ((pindex = pindex->pprev) == NULL)
 245                     return error("CheckSync: pprev null - block index structure failure");
 246             if (pindex->nHeight < pindexSync->nHeight || pindex->GetBlockHash() != hashSyncCheckpoint)
 247                 return false; // only descendant of sync-checkpoint can pass check
 248         }
 249         if (nHeight == pindexSync->nHeight && hashBlock != hashSyncCheckpoint)
 250             return false; // same height with sync-checkpoint
 251         if (nHeight < pindexSync->nHeight && !mapBlockIndex.count(hashBlock))
 252             return false; // lower height than sync-checkpoint
 253         return true;
 254     }
 255
 256     bool WantedByPendingSyncCheckpoint(uint256 hashBlock)
 257     {
 258         LOCK(cs_hashSyncCheckpoint);
 259         if (hashPendingCheckpoint == 0)
 260             return false;
 261         if (hashBlock == hashPendingCheckpoint)
 262             return true;
 263         if (mapOrphanBlocks.count(hashPendingCheckpoint)
 264             && hashBlock == WantedByOrphan(mapOrphanBlocks[hashPendingCheckpoint]))
 265             return true;
 266         return false;
 267     }
 268
 269     // ppcoin: reset synchronized checkpoint to last hardened checkpoint
 270     bool ResetSyncCheckpoint()
 271     {
 272         LOCK(cs_hashSyncCheckpoint);
 273         const uint256& hash = mapCheckpoints.rbegin()->second.first;
 274         if (mapBlockIndex.count(hash) && !mapBlockIndex[hash]->IsInMainChain())
 275         {
 276             // checkpoint block accepted but not yet in main chain
 277             printf("ResetSyncCheckpoint: SetBestChain to hardened checkpoint %s\n", hash.ToString().c_str());
 278             CTxDB txdb;
 279             CBlock block;
 280             if (!block.ReadFromDisk(mapBlockIndex[hash]))
 281                 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
 282             if (!block.SetBestChain(txdb, mapBlockIndex[hash]))
 283             {
 284                 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
 285             }
 286         }
 287         else if(!mapBlockIndex.count(hash))
 288         {
 289             // checkpoint block not yet accepted
 290             hashPendingCheckpoint = hash;
 291             checkpointMessagePending.SetNull();
 292             printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
 293         }
 294
 295         for(auto it = mapCheckpoints.rbegin(); it != mapCheckpoints.rend(); ++it)
 296         {
 297             const uint256& hash = it->second.first;
 298             if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
 299             {
 300                 if (!WriteSyncCheckpoint(hash))
 301                     return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
 302                 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
 303                 return true;
 304             }
 305         }
 306
 307         return false;
 308     }
 309
 310     void AskForPendingSyncCheckpoint(CNode* pfrom)
 311     {
 312         LOCK(cs_hashSyncCheckpoint);
 313         if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
 314             pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
 315     }
 316
 317     bool SetCheckpointPrivKey(std::string strPrivKey)
 318     {
 319         // Test signing a sync-checkpoint with genesis block
 320         CSyncCheckpoint checkpoint;
 321         checkpoint.hashCheckpoint = !fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet;
 322         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 323         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 324         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 325
 326         std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
 327         CKey key;
 328         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 329         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 330             return false;
 331
 332         // Test signing successful, proceed
 333         CSyncCheckpoint::strMasterPrivKey = strPrivKey;
 334         return true;
 335     }
 336
 337     bool SendSyncCheckpoint(uint256 hashCheckpoint)
 338     {
 339         CSyncCheckpoint checkpoint;
 340         checkpoint.hashCheckpoint = hashCheckpoint;
 341         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 342         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 343         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 344
 345         if (CSyncCheckpoint::strMasterPrivKey.empty())
 346             return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
 347         std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
 348         CKey key;
 349         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 350         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 351             return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
 352
 353         if(!checkpoint.ProcessSyncCheckpoint(NULL))
 354         {
 355             printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
 356             return false;
 357         }
 358
 359         // Relay checkpoint
 360         {
 361             LOCK(cs_vNodes);
 362             for (std::vector<CNode*>::iterator it = vNodes.begin(); it != vNodes.end(); ++it)
 363                 checkpoint.RelayTo(*it);
 364         }
 365         return true;
 366     }
 367
 368     // Is the sync-checkpoint outside maturity window?
 369     bool IsMatureSyncCheckpoint()
 370     {
 371         LOCK(cs_hashSyncCheckpoint);
 372         // sync-checkpoint should always be accepted block
 373         assert(mapBlockIndex.count(hashSyncCheckpoint));
 374         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 375         return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
 376                 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
 377     }
 378 }
 379
 380 // ppcoin: sync-checkpoint master key
 381 const std::string CSyncCheckpoint::strMasterPubKey = "04a51b735f816de4ec3f891d5b38bbc91e1f7245c7c08d17990760b86b4d8fc3910a850ffecf73bfa8886f01739a0c4c4322201282d07b6e48ce931cc92af94850";
 382
 383 std::string CSyncCheckpoint::strMasterPrivKey = "";
 384
 385 // ppcoin: verify signature of sync-checkpoint message
 386 bool CSyncCheckpoint::CheckSignature()
 387 {
 388     CPubKey key(ParseHex(CSyncCheckpoint::strMasterPubKey));
 389     if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
 390         return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
 391
 392     // Now unserialize the data
 393     CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
 394     sMsg >> *(CUnsignedSyncCheckpoint*)this;
 395     return true;
 396 }
 397
 398 // process synchronized checkpoint
 399 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
 400 {
 401     if (!CheckSignature())
 402         return false;
 403
 404     LOCK(Checkpoints::cs_hashSyncCheckpoint);
 405     if (!mapBlockIndex.count(hashCheckpoint))
 406     {
 407         // We haven't received the checkpoint chain, keep the checkpoint as pending
 408         Checkpoints::hashPendingCheckpoint = hashCheckpoint;
 409         Checkpoints::checkpointMessagePending = *this;
 410         printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
 411         // Ask this guy to fill in what we're missing
 412         if (pfrom)
 413         {
 414             pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
 415             // ask directly as well in case rejected earlier by duplicate
 416             // proof-of-stake because getblocks may not get it this time
 417             pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
 418         }
 419         return false;
 420     }
 421
 422     if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
 423         return false;
 424
 425     CTxDB txdb;
 426     CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
 427     if (!pindexCheckpoint->IsInMainChain())
 428     {
 429         // checkpoint chain received but not yet main chain
 430         CBlock block;
 431         if (!block.ReadFromDisk(pindexCheckpoint))
 432             return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 433         if (!block.SetBestChain(txdb, pindexCheckpoint))
 434         {
 435             Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
 436             return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 437         }
 438     }
 439
 440     if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
 441         return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
 442     Checkpoints::checkpointMessage = *this;
 443     Checkpoints::hashPendingCheckpoint = 0;
 444     Checkpoints::checkpointMessagePending.SetNull();
 445     printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());
 446     return true;
 447 }