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         ( 68600, std::make_pair(uint256("0xb646b0562080ab9411f85d4b2a1ca8b197c67ae170c5e328406871b44233cb06"), 1389867276) )
  29         ( 92161, std::make_pair(uint256("0x000000000079090eb31e7fa55487e4e666466253e68b213f44b7977ea7a2eeec"), 1398919969) )
  30         ( 98661, std::make_pair(uint256("0x48328dfc0eaffc659723739c6202854d1624449340193bdea3e71ece4ccdd43f"), 1401469019) )
  31     ;
  32
  33     // TestNet has no checkpoints
  34     static MapCheckpoints mapCheckpointsTestnet =
  35         boost::assign::map_list_of
  36         ( 0, std::make_pair(hashGenesisBlockTestNet, 1360105017) )
  37         ;
  38
  39     bool CheckHardened(int nHeight, const uint256& hash)
  40     {
  41         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  42
  43         MapCheckpoints::const_iterator i = checkpoints.find(nHeight);
  44         if (i == checkpoints.end()) return true;
  45         return hash == i->second.first;
  46     }
  47
  48     int GetTotalBlocksEstimate()
  49     {
  50         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  51
  52         return checkpoints.rbegin()->first;
  53     }
  54
  55     int GetLastCheckpointTime()
  56     {
  57         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  58
  59         return checkpoints.rbegin()->second.second;
  60     }
  61
  62     CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
  63     {
  64         MapCheckpoints& checkpoints = (fTestNet ? mapCheckpointsTestnet : mapCheckpoints);
  65
  66         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, checkpoints)
  67         {
  68             const uint256& hash = i.second.first;
  69             std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
  70             if (t != mapBlockIndex.end())
  71                 return t->second;
  72         }
  73         return NULL;
  74     }
  75
  76     // ppcoin: synchronized checkpoint (centrally broadcasted)
  77     uint256 hashSyncCheckpoint = 0;
  78     uint256 hashPendingCheckpoint = 0;
  79     CSyncCheckpoint checkpointMessage;
  80     CSyncCheckpoint checkpointMessagePending;
  81     uint256 hashInvalidCheckpoint = 0;
  82     CCriticalSection cs_hashSyncCheckpoint;
  83
  84     // ppcoin: get last synchronized checkpoint
  85     CBlockIndex* GetLastSyncCheckpoint()
  86     {
  87         LOCK(cs_hashSyncCheckpoint);
  88         if (!mapBlockIndex.count(hashSyncCheckpoint))
  89             error("GetSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
  90         else
  91             return mapBlockIndex[hashSyncCheckpoint];
  92         return NULL;
  93     }
  94
  95     // ppcoin: only descendant of current sync-checkpoint is allowed
  96     bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
  97     {
  98         if (!mapBlockIndex.count(hashSyncCheckpoint))
  99             return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
 100         if (!mapBlockIndex.count(hashCheckpoint))
 101             return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
 102
 103         CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
 104         CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
 105
 106         if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
 107         {
 108             // Received an older checkpoint, trace back from current checkpoint
 109             // to the same height of the received checkpoint to verify
 110             // that current checkpoint should be a descendant block
 111             CBlockIndex* pindex = pindexSyncCheckpoint;
 112             while (pindex->nHeight > pindexCheckpointRecv->nHeight)
 113                 if (!(pindex = pindex->pprev))
 114                     return error("ValidateSyncCheckpoint: pprev null - block index structure failure");
 115             if (pindex->GetBlockHash() != hashCheckpoint)
 116             {
 117                 hashInvalidCheckpoint = hashCheckpoint;
 118                 return error("ValidateSyncCheckpoint: new sync-checkpoint %s is conflicting with current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 119             }
 120             return false; // ignore older checkpoint
 121         }
 122
 123         // Received checkpoint should be a descendant block of the current
 124         // checkpoint. Trace back to the same height of current checkpoint
 125         // to verify.
 126         CBlockIndex* pindex = pindexCheckpointRecv;
 127         while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
 128             if (!(pindex = pindex->pprev))
 129                 return error("ValidateSyncCheckpoint: pprev2 null - block index structure failure");
 130         if (pindex->GetBlockHash() != hashSyncCheckpoint)
 131         {
 132             hashInvalidCheckpoint = hashCheckpoint;
 133             return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
 134         }
 135         return true;
 136     }
 137
 138     bool WriteSyncCheckpoint(const uint256& hashCheckpoint)
 139     {
 140         {
 141             LOCK(Checkpoints::cs_hashSyncCheckpoint);
 142
 143             if (!pblocktree->WriteSyncCheckpoint(hashCheckpoint))
 144             {
 145                 return error("WriteSyncCheckpoint(): failed to write to db sync checkpoint %s", hashCheckpoint.ToString().c_str());
 146             }
 147         }
 148
 149         Checkpoints::hashSyncCheckpoint = hashCheckpoint;
 150         return true;
 151     }
 152
 153     bool AcceptPendingSyncCheckpoint()
 154     {
 155         LOCK(cs_hashSyncCheckpoint);
 156         if (hashPendingCheckpoint != 0 && mapBlockIndex.count(hashPendingCheckpoint))
 157         {
 158             if (!ValidateSyncCheckpoint(hashPendingCheckpoint))
 159             {
 160                 hashPendingCheckpoint = 0;
 161                 checkpointMessagePending.SetNull();
 162                 return false;
 163             }
 164
 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 (!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             CBlock block;
 256             if (!block.ReadFromDisk(mapBlockIndex[hash]))
 257                 return error("ResetSyncCheckpoint: ReadFromDisk failed for hardened checkpoint %s", hash.ToString().c_str());
 258             if (!SetBestChain(mapBlockIndex[hash]))
 259             {
 260                 return error("ResetSyncCheckpoint: SetBestChain failed for hardened checkpoint %s", hash.ToString().c_str());
 261             }
 262         }
 263         else if(!mapBlockIndex.count(hash))
 264         {
 265             // checkpoint block not yet accepted
 266             hashPendingCheckpoint = hash;
 267             checkpointMessagePending.SetNull();
 268             printf("ResetSyncCheckpoint: pending for sync-checkpoint %s\n", hashPendingCheckpoint.ToString().c_str());
 269         }
 270
 271         BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
 272         {
 273             const uint256& hash = i.second.first;
 274             if (mapBlockIndex.count(hash) && mapBlockIndex[hash]->IsInMainChain())
 275             {
 276                 if (!WriteSyncCheckpoint(hash))
 277                     return error("ResetSyncCheckpoint: failed to write sync checkpoint %s", hash.ToString().c_str());
 278                 printf("ResetSyncCheckpoint: sync-checkpoint reset to %s\n", hashSyncCheckpoint.ToString().c_str());
 279                 return true;
 280             }
 281         }
 282
 283         return false;
 284     }
 285
 286     void AskForPendingSyncCheckpoint(CNode* pfrom)
 287     {
 288         LOCK(cs_hashSyncCheckpoint);
 289         if (pfrom && hashPendingCheckpoint != 0 && (!mapBlockIndex.count(hashPendingCheckpoint)) && (!mapOrphanBlocks.count(hashPendingCheckpoint)))
 290             pfrom->AskFor(CInv(MSG_BLOCK, hashPendingCheckpoint));
 291     }
 292
 293     bool SetCheckpointPrivKey(std::string strPrivKey)
 294     {
 295         // Test signing a sync-checkpoint with genesis block
 296         CSyncCheckpoint checkpoint;
 297         checkpoint.hashCheckpoint = !fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet;
 298         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 299         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 300         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 301
 302         std::vector<unsigned char> vchPrivKey = ParseHex(strPrivKey);
 303         CKey key;
 304         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 305         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 306             return false;
 307
 308         // Test signing successful, proceed
 309         CSyncCheckpoint::strMasterPrivKey = strPrivKey;
 310         return true;
 311     }
 312
 313     bool SendSyncCheckpoint(uint256 hashCheckpoint)
 314     {
 315         CSyncCheckpoint checkpoint;
 316         checkpoint.hashCheckpoint = hashCheckpoint;
 317         CDataStream sMsg(SER_NETWORK, PROTOCOL_VERSION);
 318         sMsg << (CUnsignedSyncCheckpoint)checkpoint;
 319         checkpoint.vchMsg = std::vector<unsigned char>(sMsg.begin(), sMsg.end());
 320
 321         if (CSyncCheckpoint::strMasterPrivKey.empty())
 322             return error("SendSyncCheckpoint: Checkpoint master key unavailable.");
 323         std::vector<unsigned char> vchPrivKey = ParseHex(CSyncCheckpoint::strMasterPrivKey);
 324         CKey key;
 325         key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
 326         if (!key.Sign(Hash(checkpoint.vchMsg.begin(), checkpoint.vchMsg.end()), checkpoint.vchSig))
 327             return error("SendSyncCheckpoint: Unable to sign checkpoint, check private key?");
 328
 329         if(!checkpoint.ProcessSyncCheckpoint(NULL))
 330         {
 331             printf("WARNING: SendSyncCheckpoint: Failed to process checkpoint.\n");
 332             return false;
 333         }
 334
 335         // Relay checkpoint
 336         {
 337             LOCK(cs_vNodes);
 338             BOOST_FOREACH(CNode* pnode, vNodes)
 339                 checkpoint.RelayTo(pnode);
 340         }
 341         return true;
 342     }
 343
 344     // Is the sync-checkpoint outside maturity window?
 345     bool IsMatureSyncCheckpoint()
 346     {
 347         LOCK(cs_hashSyncCheckpoint);
 348         // sync-checkpoint should always be accepted block
 349         assert(mapBlockIndex.count(hashSyncCheckpoint));
 350         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 351         return (nBestHeight >= pindexSync->nHeight + nCoinbaseMaturity ||
 352                 pindexSync->GetBlockTime() + nStakeMinAge < GetAdjustedTime());
 353     }
 354
 355     // Is the sync-checkpoint too old?
 356     bool IsSyncCheckpointTooOld(unsigned int nSeconds)
 357     {
 358         LOCK(cs_hashSyncCheckpoint);
 359         // sync-checkpoint should always be accepted block
 360         assert(mapBlockIndex.count(hashSyncCheckpoint));
 361         const CBlockIndex* pindexSync = mapBlockIndex[hashSyncCheckpoint];
 362         return (pindexSync->GetBlockTime() + nSeconds < GetAdjustedTime());
 363     }
 364 }
 365
 366 // ppcoin: sync-checkpoint master key
 367 const std::string CSyncCheckpoint::strMasterPubKey = "04a51b735f816de4ec3f891d5b38bbc91e1f7245c7c08d17990760b86b4d8fc3910a850ffecf73bfa8886f01739a0c4c4322201282d07b6e48ce931cc92af94850";
 368
 369 std::string CSyncCheckpoint::strMasterPrivKey = "";
 370
 371 // ppcoin: verify signature of sync-checkpoint message
 372 bool CSyncCheckpoint::CheckSignature()
 373 {
 374     CKey key;
 375     if (!key.SetPubKey(ParseHex(CSyncCheckpoint::strMasterPubKey)))
 376         return error("CSyncCheckpoint::CheckSignature() : SetPubKey failed");
 377     if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
 378         return error("CSyncCheckpoint::CheckSignature() : verify signature failed");
 379
 380     // Now unserialize the data
 381     CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
 382     sMsg >> *(CUnsignedSyncCheckpoint*)this;
 383     return true;
 384 }
 385
 386 // ppcoin: process synchronized checkpoint
 387 bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
 388 {
 389     if (!CheckSignature())
 390         return false;
 391
 392     LOCK(Checkpoints::cs_hashSyncCheckpoint);
 393     if (!mapBlockIndex.count(hashCheckpoint))
 394     {
 395         // We haven't received the checkpoint chain, keep the checkpoint as pending
 396         Checkpoints::hashPendingCheckpoint = hashCheckpoint;
 397         Checkpoints::checkpointMessagePending = *this;
 398         printf("ProcessSyncCheckpoint: pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
 399         // Ask this guy to fill in what we're missing
 400         if (pfrom)
 401         {
 402             pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
 403             // ask directly as well in case rejected earlier by duplicate
 404             // proof-of-stake because getblocks may not get it this time
 405             pfrom->AskFor(CInv(MSG_BLOCK, mapOrphanBlocks.count(hashCheckpoint)? WantedByOrphan(mapOrphanBlocks[hashCheckpoint]) : hashCheckpoint));
 406         }
 407         return false;
 408     }
 409
 410     if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
 411         return false;
 412
 413     CBlockIndex* pindexCheckpoint = mapBlockIndex[hashCheckpoint];
 414     if (!pindexCheckpoint->IsInMainChain())
 415     {
 416         // checkpoint chain received but not yet main chain
 417         CBlock block;
 418         if (!block.ReadFromDisk(pindexCheckpoint))
 419             return error("ProcessSyncCheckpoint: ReadFromDisk failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 420         if (!SetBestChain(pindexCheckpoint))
 421         {
 422             Checkpoints::hashInvalidCheckpoint = hashCheckpoint;
 423             return error("ProcessSyncCheckpoint: SetBestChain failed for sync checkpoint %s", hashCheckpoint.ToString().c_str());
 424         }
 425     }
 426
 427     if (!Checkpoints::WriteSyncCheckpoint(hashCheckpoint))
 428         return error("ProcessSyncCheckpoint(): failed to write sync checkpoint %s", hashCheckpoint.ToString().c_str());
 429     Checkpoints::checkpointMessage = *this;
 430     Checkpoints::hashPendingCheckpoint = 0;
 431     Checkpoints::checkpointMessagePending.SetNull();
 432     printf("ProcessSyncCheckpoint: sync-checkpoint at %s\n", hashCheckpoint.ToString().c_str());
 433     return true;
 434 }