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     typedef std::map<int, std::pair<uint256, unsigned int> > MapCheckpoints;
  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         boost::assign::map_list_of
  27         ( 0,     std::make_pair(hashGenesisBlock, 1360105017) )
  28         ( 9690,  std::make_pair(uint256("0x00000000026561450859c46868099e0df6068a538f038cb18988fd8d47dcdaf5"), 1362791423) )
  29         ( 13560, std::make_pair(uint256("0xa1591a0fcbf11f282d671581edb9f0aadcd06fee69761081e0a3245914c13729"), 1364674052) )
  30         ( 37092, std::make_pair(uint256("0x0000000000a38c2f98556f46793b453e92d8fab2d31c0b93fd08bcf78e56099d"), 1376677203) )
  31         ( 44200, std::make_pair(uint256("0xc9bda7232a18b9c1f5ff974a9e5566b2d1879ceb8fc0e9e61fba9038a25b8447"), 1380145962) )
  32         ( 65000, std::make_pair(uint256("0xfb2b51a2fd65062c98a7a6053cde46aeaefebb95ba2f680e85a29ee25b1dcf05"), 1388526385) )
  33     ;
  34
  35     // TestNet has no checkpoints
  36     static MapCheckpoints mapCheckpointsTestnet =
  37         boost::assign::map_list_of
  38         ( 0, std::make_pair(hashGenesisBlockTestNet, 1360105017) )
  39         ;
  40
  41     bool CheckHardened(int nHeight, const uint256& hash)
  42     {
  43         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  44
  45         MapCheckpoints::const_iterator i = checkpoints.find(nHeight);
  46         if (i == checkpoints.end()) return true;
  47         return hash == i->second.first;
  48     }
  49
  50     int GetTotalBlocksEstimate()
  51     {
  52         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  53
  54         return checkpoints.rbegin()->first;
  55     }
  56
  57     int GetLastCheckpointTime()
  58     {
  59         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  60
  61         return checkpoints.rbegin()->second.second;
  62     }
  63
  64     CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
  65     {
  66         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  67
  68         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, checkpoints)
  69         {
  70             const uint256& hash = i.second.first;
  71             std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
  72             if (t != mapBlockIndex.end())
  73                 return t->second;
  74         }
  75         return NULL;
  76     }
  77
  78     // ppcoin: synchronized checkpoint (centrally broadcasted)
  79     uint256 hashSyncCheckpoint = 0;
  80     uint256 hashPendingCheckpoint = 0;
  81     CSyncCheckpoint checkpointMessage;
  82     CSyncCheckpoint checkpointMessagePending;
  83     uint256 hashInvalidCheckpoint = 0;
  84     CCriticalSection cs_hashSyncCheckpoint;
  85
  86     // ppcoin: get last synchronized checkpoint
  87     CBlockIndex* GetLastSyncCheckpoint()
  88     {
  89         LOCK(cs_hashSyncCheckpoint);
  90         if (!mapBlockIndex.count(hashSyncCheckpoint))
  91             error("GetSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
  92         else
  93             return mapBlockIndex[hashSyncCheckpoint];
  94         return NULL;
  95     }
  96
  97     // ppcoin: only descendant of current sync-checkpoint is allowed
  98     bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
  99     {
 100         if (!mapBlockIndex.count(hashSyncCheckpoint))
 101             return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
 102         if (!mapBlockIndex.count(hashCheckpoint))
 103             return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
 104
 105         CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
 106         CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
 107
 108         if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
 109         {
 110             // Received an older checkpoint, trace back from current checkpoint
 111             // to the same height of the received checkpoint to verify
 112             // that current checkpoint should be a descendant block
 113             CBlockIndex* pindex = pindexSyncCheckpoint;
 114             while (pindex->nHeight > pindexCheckpointRecv->nHeight)
 115                 if (!(pindex = pindex->pprev))
 116                     return error("ValidateSyncCheckpoint: pprev null - block index structure failure");
 117             if (pindex->GetBlockHash() != hashCheckpoint)
 118             {
 119                 hashInvalidCheckpoint = hashCheckpoint;
 120                 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is conflicting with current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 121             }
 122             return false; // ignore older checkpoint
 123         }
 124
 125         // Received checkpoint should be a descendant block of the current
 126         // checkpoint. Trace back to the same height of current checkpoint
 127         // to verify.
 128         CBlockIndex* pindex = pindexCheckpointRecv;
 129         while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
 130             if (!(pindex = pindex->pprev))
 131                 return error("ValidateSyncCheckpoint: pprev2 null - block index structure failure");
 132         if (pindex->GetBlockHash() != hashSyncCheckpoint)
 133         {
 134             hashInvalidCheckpoint = hashCheckpoint;
 135             return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 136         }
 137         return true;
 138     }
 139
 140     bool WriteSyncCheckpoint(const uint256& hashCheckpoint)
 141     {
 142         CTxDB txdb;
 143         txdb.TxnBegin();
 144         if (!txdb.WriteSyncCheckpoint(hashCheckpoint))
 145         {
 146             txdb.TxnAbort();
 147             return error("WriteSyncCheckpoint(): failed to write to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 148         }
 149         if (!txdb.TxnCommit())
 150             return error("WriteSyncCheckpoint(): failed to commit to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 151
 152         Checkpoints::hashSyncCheckpoint = hashCheckpoint;
 153         return true;
 154     }
 155
 156     bool AcceptPendingSyncCheckpoint()
 157     {
 158         LOCK(cs_hashSyncCheckpoint);
 159         if (hashPendingCheckpoint != 0 && mapBlockIndex.count(hashPendingCheckpoint))
 160         {
 161             if (!ValidateSyncCheckpoint(hashPendingCheckpoint))
 162             {
 163                 hashPendingCheckpoint = 0;
 164                 checkpointMessagePending.SetNull();
 165                 return false;
 166             }
 167
 168             CTxDB txdb;
 169             CBlockIndex* pindexCheckpoint = mapBlockIndex[hashPendingCheckpoint];
 170             if (!pindexCheckpoint->IsInMainChain())
 171             {
 172                 CBlock block;
 173                 if (!block.ReadFromDisk(pindexCheckpoint))
 174                     return error("AcceptPendingSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 175                 if (!block.SetBestChain(txdb, pindexCheckpoint))
 176                 {
 177                     hashInvalidCheckpoint = hashPendingCheckpoint;
 178                     return error("AcceptPendingSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 179                 }
 180             }
 181
 182             if (!WriteSyncCheckpoint(hashPendingCheckpoint))
 183                 return error("AcceptPendingSyncCheckpoint(): failed to write sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 184             hashPendingCheckpoint = 0;
 185             checkpointMessage = checkpointMessagePending;
 186             checkpointMessagePending.SetNull();
 187             printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
 188             // relay the checkpoint
 189             if (!checkpointMessage.IsNull())
 190             {
 191                 BOOST_FOREACH(CNode* pnode, vNodes)
 192                     checkpointMessage.RelayTo(pnode);
 193             }
 194             return true;
 195         }
 196         return false;
 197     }
 198
 199     // Automatically select a suitable sync-checkpoint
 200     uint256 AutoSelectSyncCheckpoint()
 201     {
 202         const CBlockIndex *pindex = pindexBest;
 203         // Search backward for a block within max span and maturity window
 204         while (pindex->pprev && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN > pindexBest->GetBlockTime() || pindex->nHeight + 8 > pindexBest->nHeight))
 205             pindex = pindex->pprev;
 206         return pindex->GetBlockHash();
 207     }
 208
 209     // Check against synchronized checkpoint
 210     bool CheckSync(const uint256& hashBlock, const CBlockIndex* pindexPrev)
 211     {
 212         if (fTestNet) return true; // Testnet has no checkpoints
 213         int nHeight = pindexPrev->nHeight + 1;
 214
 215         LOCK(cs_hashSyncCheckpoint);
 216         // sync-checkpoint should always be accepted block
 217         assert(mapBlockIndex.count(hashSyncCheckpoint));
 218         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 219
 220         if (nHeight > pindexSync->nHeight)
 221         {
 222             // trace back to same height as sync-checkpoint
 223             const CBlockIndex* pindex = pindexPrev;
 224             while (pindex->nHeight > pindexSync->nHeight)
 225                 if (!(pindex = pindex->pprev))
 226                     return error("CheckSync: pprev null - block index structure failure");
 227             if (pindex->nHeight < pindexSync->nHeight || pindex->GetBlockHash() != hashSyncCheckpoint)
 228                 return false; // only descendant of sync-checkpoint can pass check
 229         }
 230         if (nHeight == pindexSync->nHeight && hashBlock != hashSyncCheckpoint)
 231             return false; // same height with sync-checkpoint
 232         if (nHeight < pindexSync->nHeight && !mapBlockIndex.count(hashBlock))
 233             return false; // lower height than sync-checkpoint
 234         return true;
 235     }
 236
 237     bool WantedByPendingSyncCheckpoint(uint256 hashBlock)
 238     {
 239         LOCK(cs_hashSyncCheckpoint);
 240         if (hashPendingCheckpoint == 0)
 241             return false;
 242         if (hashBlock == hashPendingCheckpoint)
 243             return true;
 244         if (mapOrphanBlocks.count(hashPendingCheckpoint)
 245             && hashBlock == WantedByOrphan(mapOrphanBlocks[hashPendingCheckpoint]))
 246             return true;
 247         return false;
 248     }
 249
 250     // ppcoin: reset synchronized checkpoint to last hardened checkpoint
 251     bool ResetSyncCheckpoint()
 252     {
 253         LOCK(cs_hashSyncCheckpoint);
 254         const uint256& hash = mapCheckpoints.rbegin()->second.first;
 255         if (mapBlockIndex.count(hash) && !mapBlockIndex[hash]->IsInMainChain())
 256         {
 257             // checkpoint block accepted but not yet in main chain
 258             printf("ResetSyncCheckpoint: SetBestChain to hardened checkpoint %s\n", hash.ToString().c_str());
 259             CTxDB txdb;
 260             CBlock block;
 261             if (!block.ReadFromDisk(mapBlockIndex[hash]))
 262                 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
 263             if (!block.SetBestChain(txdb, mapBlockIndex[hash]))
 264             {
 265                 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
 266             }
 267         }
 268         else if(!mapBlockIndex.count(hash))
 269         {
 270             // checkpoint block not yet accepted
 271             hashPendingCheckpoint = hash;
 272             checkpointMessagePending.SetNull();
 273             printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
 274         }
 275
 276         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
 277         {
 278             const uint256& hash = i.second.first;
 279             if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
 280             {
 281                 if (!WriteSyncCheckpoint(hash))
 282                     return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
 283                 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
 284                 return true;
 285             }
 286         }
 287
 288         return false;
 289     }
 290
 291     void AskForPendingSyncCheckpoint(CNode* pfrom)
 292     {
 293         LOCK(cs_hashSyncCheckpoint);
 294         if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
 295             pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
 296     }
 297
 298     bool SetCheckpointPrivKey(std::string strPrivKey)
 299     {
 300         // Test signing a sync-checkpoint with genesis block
 301         CSyncCheckpoint checkpoint;
 302         checkpoint.hashCheckpoint = !fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet;
 303         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 304         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 305         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 306
 307         std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
 308         CKey key;
 309         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 310         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 311             return false;
 312
 313         // Test signing successful, proceed
 314         CSyncCheckpoint::strMasterPrivKey = strPrivKey;
 315         return true;
 316     }
 317
 318     bool SendSyncCheckpoint(uint256 hashCheckpoint)
 319     {
 320         CSyncCheckpoint checkpoint;
 321         checkpoint.hashCheckpoint = hashCheckpoint;
 322         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 323         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 324         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 325
 326         if (CSyncCheckpoint::strMasterPrivKey.empty())
 327             return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
 328         std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
 329         CKey key;
 330         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 331         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 332             return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
 333
 334         if(!checkpoint.ProcessSyncCheckpoint(NULL))
 335         {
 336             printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
 337             return false;
 338         }
 339
 340         // Relay checkpoint
 341         {
 342             LOCK(cs_vNodes);
 343             BOOST_FOREACH(CNode* pnode, vNodes)
 344                 checkpoint.RelayTo(pnode);
 345         }
 346         return true;
 347     }
 348
 349     // Is the sync-checkpoint outside maturity window?
 350     bool IsMatureSyncCheckpoint()
 351     {
 352         LOCK(cs_hashSyncCheckpoint);
 353         // sync-checkpoint should always be accepted block
 354         assert(mapBlockIndex.count(hashSyncCheckpoint));
 355         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 356         return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
 357                 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
 358     }
 359
 360     // Is the sync-checkpoint too old?
 361     bool IsSyncCheckpointTooOld(unsigned int nSeconds)
 362     {
 363         LOCK(cs_hashSyncCheckpoint);
 364         // sync-checkpoint should always be accepted block
 365         assert(mapBlockIndex.count(hashSyncCheckpoint));
 366         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 367         return (pindexSync->GetBlockTime() + nSeconds < GetAdjustedTime());
 368     }
 369 }
 370
 371 // ppcoin: sync-checkpoint master key
 372 const std::string CSyncCheckpoint::strMasterPubKey = "04a51b735f816de4ec3f891d5b38bbc91e1f7245c7c08d17990760b86b4d8fc3910a850ffecf73bfa8886f01739a0c4c4322201282d07b6e48ce931cc92af94850";
 373
 374 std::string CSyncCheckpoint::strMasterPrivKey = "";
 375
 376 // ppcoin: verify signature of sync-checkpoint message
 377 bool CSyncCheckpoint::CheckSignature()
 378 {
 379     CKey key;
 380     if (!key.SetPubKey(ParseHex(CSyncCheckpoint::strMasterPubKey)))
 381         return error("CSyncCheckpoint::CheckSignature() : SetPubKey failed");
 382     if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
 383         return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
 384
 385     // Now unserialize the data
 386     CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
 387     sMsg >> *(CUnsignedSyncCheckpoint*)this;
 388     return true;
 389 }
 390
 391 // ppcoin: process synchronized checkpoint
 392 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
 393 {
 394     if (!CheckSignature())
 395         return false;
 396
 397     LOCK(Checkpoints::cs_hashSyncCheckpoint);
 398     if (!mapBlockIndex.count(hashCheckpoint))
 399     {
 400         // We haven't received the checkpoint chain, keep the checkpoint as pending
 401         Checkpoints::hashPendingCheckpoint = hashCheckpoint;
 402         Checkpoints::checkpointMessagePending = *this;
 403         printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
 404         // Ask this guy to fill in what we're missing
 405         if (pfrom)
 406         {
 407             pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
 408             // ask directly as well in case rejected earlier by duplicate
 409             // proof-of-stake because getblocks may not get it this time
 410             pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
 411         }
 412         return false;
 413     }
 414
 415     if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
 416         return false;
 417
 418     CTxDB txdb;
 419     CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
 420     if (!pindexCheckpoint->IsInMainChain())
 421     {
 422         // checkpoint chain received but not yet main chain
 423         CBlock block;
 424         if (!block.ReadFromDisk(pindexCheckpoint))
 425             return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 426         if (!block.SetBestChain(txdb, pindexCheckpoint))
 427         {
 428             Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
 429             return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 430         }
 431     }
 432
 433     if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
 434         return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
 435     Checkpoints::checkpointMessage = *this;
 436     Checkpoints::hashPendingCheckpoint = 0;
 437     Checkpoints::checkpointMessagePending.SetNull();
 438     printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());
 439     return true;
 440 }