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     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         ( 65000, std::make_pair(uint256("0xb646b0562080ab9411f85d4b2a1ca8b197c67ae170c5e328406871b44233cb06"), 1389867276) )
  29     ;
  30
  31     // TestNet has no checkpoints
  32     static MapCheckpoints mapCheckpointsTestnet =
  33         boost::assign::map_list_of
  34         ( 0, std::make_pair(hashGenesisBlockTestNet, 1360105017) )
  35         ;
  36
  37     bool CheckHardened(int nHeight, const uint256& hash)
  38     {
  39         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  40
  41         MapCheckpoints::const_iterator i = checkpoints.find(nHeight);
  42         if (i == checkpoints.end()) return true;
  43         return hash == i->second.first;
  44     }
  45
  46     int GetTotalBlocksEstimate()
  47     {
  48         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  49
  50         return checkpoints.rbegin()->first;
  51     }
  52
  53     int GetLastCheckpointTime()
  54     {
  55         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  56
  57         return checkpoints.rbegin()->second.second;
  58     }
  59
  60     CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
  61     {
  62         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  63
  64         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, checkpoints)
  65         {
  66             const uint256& hash = i.second.first;
  67             std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
  68             if (t != mapBlockIndex.end())
  69                 return t->second;
  70         }
  71         return NULL;
  72     }
  73
  74     // ppcoin: synchronized checkpoint (centrally broadcasted)
  75     uint256 hashSyncCheckpoint = 0;
  76     uint256 hashPendingCheckpoint = 0;
  77     CSyncCheckpoint checkpointMessage;
  78     CSyncCheckpoint checkpointMessagePending;
  79     uint256 hashInvalidCheckpoint = 0;
  80     CCriticalSection cs_hashSyncCheckpoint;
  81
  82     // ppcoin: get last synchronized checkpoint
  83     CBlockIndex* GetLastSyncCheckpoint()
  84     {
  85         LOCK(cs_hashSyncCheckpoint);
  86         if (!mapBlockIndex.count(hashSyncCheckpoint))
  87             error("GetSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
  88         else
  89             return mapBlockIndex[hashSyncCheckpoint];
  90         return NULL;
  91     }
  92
  93     // ppcoin: only descendant of current sync-checkpoint is allowed
  94     bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
  95     {
  96         if (!mapBlockIndex.count(hashSyncCheckpoint))
  97             return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
  98         if (!mapBlockIndex.count(hashCheckpoint))
  99             return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
 100
 101         CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
 102         CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
 103
 104         if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
 105         {
 106             // Received an older checkpoint, trace back from current checkpoint
 107             // to the same height of the received checkpoint to verify
 108             // that current checkpoint should be a descendant block
 109             CBlockIndex* pindex = pindexSyncCheckpoint;
 110             while (pindex->nHeight > pindexCheckpointRecv->nHeight)
 111                 if (!(pindex = pindex->pprev))
 112                     return error("ValidateSyncCheckpoint: pprev null - block index structure failure");
 113             if (pindex->GetBlockHash() != hashCheckpoint)
 114             {
 115                 hashInvalidCheckpoint = hashCheckpoint;
 116                 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is conflicting with current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 117             }
 118             return false; // ignore older checkpoint
 119         }
 120
 121         // Received checkpoint should be a descendant block of the current
 122         // checkpoint. Trace back to the same height of current checkpoint
 123         // to verify.
 124         CBlockIndex* pindex = pindexCheckpointRecv;
 125         while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
 126             if (!(pindex = pindex->pprev))
 127                 return error("ValidateSyncCheckpoint: pprev2 null - block index structure failure");
 128         if (pindex->GetBlockHash() != hashSyncCheckpoint)
 129         {
 130             hashInvalidCheckpoint = hashCheckpoint;
 131             return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 132         }
 133         return true;
 134     }
 135
 136     bool WriteSyncCheckpoint(const uint256& hashCheckpoint)
 137     {
 138         CChainDB chaindb;
 139         chaindb.TxnBegin();
 140         if (!chaindb.WriteSyncCheckpoint(hashCheckpoint))
 141         {
 142             chaindb.TxnAbort();
 143             return error("WriteSyncCheckpoint(): failed to write to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 144         }
 145         if (!chaindb.TxnCommit())
 146             return error("WriteSyncCheckpoint(): failed to commit to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 147
 148         Checkpoints::hashSyncCheckpoint = hashCheckpoint;
 149         return true;
 150     }
 151
 152     bool AcceptPendingSyncCheckpoint()
 153     {
 154         LOCK(cs_hashSyncCheckpoint);
 155         if (hashPendingCheckpoint != 0 && mapBlockIndex.count(hashPendingCheckpoint))
 156         {
 157             if (!ValidateSyncCheckpoint(hashPendingCheckpoint))
 158             {
 159                 hashPendingCheckpoint = 0;
 160                 checkpointMessagePending.SetNull();
 161                 return false;
 162             }
 163
 164             CChainDB chaindb;
 165             CBlockIndex* pindexCheckpoint = mapBlockIndex[hashPendingCheckpoint];
 166             if (!pindexCheckpoint->IsInMainChain())
 167             {
 168                 CBlock block;
 169                 if (!block.ReadFromDisk(pindexCheckpoint))
 170                     return error("AcceptPendingSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 171                 if (!block.SetBestChain(pindexCheckpoint))
 172                 {
 173                     hashInvalidCheckpoint = hashPendingCheckpoint;
 174                     return error("AcceptPendingSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 175                 }
 176             }
 177
 178             if (!WriteSyncCheckpoint(hashPendingCheckpoint))
 179                 return error("AcceptPendingSyncCheckpoint(): failed to write sync checkpoint %s", hashPendingCheckpoint.ToString().c_str());
 180             hashPendingCheckpoint = 0;
 181             checkpointMessage = checkpointMessagePending;
 182             checkpointMessagePending.SetNull();
 183             printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
 184             // relay the checkpoint
 185             if (!checkpointMessage.IsNull())
 186             {
 187                 BOOST_FOREACH(CNode* pnode, vNodes)
 188                     checkpointMessage.RelayTo(pnode);
 189             }
 190             return true;
 191         }
 192         return false;
 193     }
 194
 195     // Automatically select a suitable sync-checkpoint
 196     uint256 AutoSelectSyncCheckpoint()
 197     {
 198         const CBlockIndex *pindex = pindexBest;
 199         // Search backward for a block within max span and maturity window
 200         while (pindex->pprev && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN > pindexBest->GetBlockTime() || pindex->nHeight + 8 > pindexBest->nHeight))
 201             pindex = pindex->pprev;
 202         return pindex->GetBlockHash();
 203     }
 204
 205     // Check against synchronized checkpoint
 206     bool CheckSync(const uint256& hashBlock, const CBlockIndex* pindexPrev)
 207     {
 208         if (fTestNet) return true; // Testnet has no checkpoints
 209         int nHeight = pindexPrev->nHeight + 1;
 210
 211         LOCK(cs_hashSyncCheckpoint);
 212         // sync-checkpoint should always be accepted block
 213         assert(mapBlockIndex.count(hashSyncCheckpoint));
 214         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 215
 216         if (nHeight > pindexSync->nHeight)
 217         {
 218             // trace back to same height as sync-checkpoint
 219             const CBlockIndex* pindex = pindexPrev;
 220             while (pindex->nHeight > pindexSync->nHeight)
 221                 if (!(pindex = pindex->pprev))
 222                     return error("CheckSync: pprev null - block index structure failure");
 223             if (pindex->nHeight < pindexSync->nHeight || pindex->GetBlockHash() != hashSyncCheckpoint)
 224                 return false; // only descendant of sync-checkpoint can pass check
 225         }
 226         if (nHeight == pindexSync->nHeight && hashBlock != hashSyncCheckpoint)
 227             return false; // same height with sync-checkpoint
 228         if (nHeight < pindexSync->nHeight && !mapBlockIndex.count(hashBlock))
 229             return false; // lower height than sync-checkpoint
 230         return true;
 231     }
 232
 233     bool WantedByPendingSyncCheckpoint(uint256 hashBlock)
 234     {
 235         LOCK(cs_hashSyncCheckpoint);
 236         if (hashPendingCheckpoint == 0)
 237             return false;
 238         if (hashBlock == hashPendingCheckpoint)
 239             return true;
 240         if (mapOrphanBlocks.count(hashPendingCheckpoint)
 241             && hashBlock == WantedByOrphan(mapOrphanBlocks[hashPendingCheckpoint]))
 242             return true;
 243         return false;
 244     }
 245
 246     // ppcoin: reset synchronized checkpoint to last hardened checkpoint
 247     bool ResetSyncCheckpoint()
 248     {
 249         LOCK(cs_hashSyncCheckpoint);
 250         const uint256& hash = mapCheckpoints.rbegin()->second.first;
 251         if (mapBlockIndex.count(hash) && !mapBlockIndex[hash]->IsInMainChain())
 252         {
 253             // checkpoint block accepted but not yet in main chain
 254             printf("ResetSyncCheckpoint: SetBestChain to hardened checkpoint %s\n", hash.ToString().c_str());
 255             CChainDB chaindb;
 256             CBlock block;
 257             if (!block.ReadFromDisk(mapBlockIndex[hash]))
 258                 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
 259             if (!block.SetBestChain(mapBlockIndex[hash]))
 260             {
 261                 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
 262             }
 263         }
 264         else if(!mapBlockIndex.count(hash))
 265         {
 266             // checkpoint block not yet accepted
 267             hashPendingCheckpoint = hash;
 268             checkpointMessagePending.SetNull();
 269             printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
 270         }
 271
 272         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
 273         {
 274             const uint256& hash = i.second.first;
 275             if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
 276             {
 277                 if (!WriteSyncCheckpoint(hash))
 278                     return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
 279                 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
 280                 return true;
 281             }
 282         }
 283
 284         return false;
 285     }
 286
 287     void AskForPendingSyncCheckpoint(CNode* pfrom)
 288     {
 289         LOCK(cs_hashSyncCheckpoint);
 290         if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
 291             pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
 292     }
 293
 294     bool SetCheckpointPrivKey(std::string strPrivKey)
 295     {
 296         // Test signing a sync-checkpoint with genesis block
 297         CSyncCheckpoint checkpoint;
 298         checkpoint.hashCheckpoint = !fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet;
 299         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 300         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 301         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 302
 303         std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
 304         CKey key;
 305         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 306         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 307             return false;
 308
 309         // Test signing successful, proceed
 310         CSyncCheckpoint::strMasterPrivKey = strPrivKey;
 311         return true;
 312     }
 313
 314     bool SendSyncCheckpoint(uint256 hashCheckpoint)
 315     {
 316         CSyncCheckpoint checkpoint;
 317         checkpoint.hashCheckpoint = hashCheckpoint;
 318         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 319         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 320         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 321
 322         if (CSyncCheckpoint::strMasterPrivKey.empty())
 323             return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
 324         std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
 325         CKey key;
 326         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 327         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 328             return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
 329
 330         if(!checkpoint.ProcessSyncCheckpoint(NULL))
 331         {
 332             printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
 333             return false;
 334         }
 335
 336         // Relay checkpoint
 337         {
 338             LOCK(cs_vNodes);
 339             BOOST_FOREACH(CNode* pnode, vNodes)
 340                 checkpoint.RelayTo(pnode);
 341         }
 342         return true;
 343     }
 344
 345     // Is the sync-checkpoint outside maturity window?
 346     bool IsMatureSyncCheckpoint()
 347     {
 348         LOCK(cs_hashSyncCheckpoint);
 349         // sync-checkpoint should always be accepted block
 350         assert(mapBlockIndex.count(hashSyncCheckpoint));
 351         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 352         return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
 353                 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
 354     }
 355
 356     // Is the sync-checkpoint too old?
 357     bool IsSyncCheckpointTooOld(unsigned int nSeconds)
 358     {
 359         LOCK(cs_hashSyncCheckpoint);
 360         // sync-checkpoint should always be accepted block
 361         assert(mapBlockIndex.count(hashSyncCheckpoint));
 362         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 363         return (pindexSync->GetBlockTime() + nSeconds < GetAdjustedTime());
 364     }
 365 }
 366
 367 // ppcoin: sync-checkpoint master key
 368 const std::string CSyncCheckpoint::strMasterPubKey = "04a51b735f816de4ec3f891d5b38bbc91e1f7245c7c08d17990760b86b4d8fc3910a850ffecf73bfa8886f01739a0c4c4322201282d07b6e48ce931cc92af94850";
 369
 370 std::string CSyncCheckpoint::strMasterPrivKey = "";
 371
 372 // ppcoin: verify signature of sync-checkpoint message
 373 bool CSyncCheckpoint::CheckSignature()
 374 {
 375     CKey key;
 376     if (!key.SetPubKey(ParseHex(CSyncCheckpoint::strMasterPubKey)))
 377         return error("CSyncCheckpoint::CheckSignature() : SetPubKey failed");
 378     if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
 379         return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
 380
 381     // Now unserialize the data
 382     CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
 383     sMsg >> *(CUnsignedSyncCheckpoint*)this;
 384     return true;
 385 }
 386
 387 // ppcoin: process synchronized checkpoint
 388 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
 389 {
 390     if (!CheckSignature())
 391         return false;
 392
 393     LOCK(Checkpoints::cs_hashSyncCheckpoint);
 394     if (!mapBlockIndex.count(hashCheckpoint))
 395     {
 396         // We haven't received the checkpoint chain, keep the checkpoint as pending
 397         Checkpoints::hashPendingCheckpoint = hashCheckpoint;
 398         Checkpoints::checkpointMessagePending = *this;
 399         printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
 400         // Ask this guy to fill in what we're missing
 401         if (pfrom)
 402         {
 403             pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
 404             // ask directly as well in case rejected earlier by duplicate
 405             // proof-of-stake because getblocks may not get it this time
 406             pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
 407         }
 408         return false;
 409     }
 410
 411     if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
 412         return false;
 413
 414     CChainDB chaindb;
 415     CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
 416     if (!pindexCheckpoint->IsInMainChain())
 417     {
 418         // checkpoint chain received but not yet main chain
 419         CBlock block;
 420         if (!block.ReadFromDisk(pindexCheckpoint))
 421             return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 422         if (!block.SetBestChain(pindexCheckpoint))
 423         {
 424             Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
 425             return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 426         }
 427     }
 428
 429     if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
 430         return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
 431     Checkpoints::checkpointMessage = *this;
 432     Checkpoints::hashPendingCheckpoint = 0;
 433     Checkpoints::checkpointMessagePending.SetNull();
 434     printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());
 435     return true;
 436 }