Merge pull request #3884

942b33a Split AcceptBlockHeader from AcceptBlock. (Pieter Wuille)
f457347 Split up CheckBlock in a block and header version (Pieter Wuille)

2 files changed, 179 insertions, 72 deletions

diff --git a/src/main.cpp b/src/main.cpp
index 7b9ca2878c..83a640d7f3 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1850,8 +1850,13 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
     if (fJustCheck)
         return true;
 
+    // Correct transaction counts.
+    pindex->nTx = block.vtx.size();
+    if (pindex->pprev)
+        pindex->nChainTx = pindex->pprev->nChainTx + block.vtx.size();
+
     // Write undo information to disk
-    if (pindex->GetUndoPos().IsNull() || (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS)
+    if (pindex->GetUndoPos().IsNull() || !pindex->IsValid(BLOCK_VALID_SCRIPTS))
     {
         if (pindex->GetUndoPos().IsNull()) {
             CDiskBlockPos pos;
@@ -1865,7 +1870,7 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
             pindex->nStatus |= BLOCK_HAVE_UNDO;
         }
 
-        pindex->nStatus = (pindex->nStatus & ~BLOCK_VALID_MASK) | BLOCK_VALID_SCRIPTS;
+        pindex->RaiseValidity(BLOCK_VALID_SCRIPTS);
 
         CDiskBlockIndex blockindex(pindex);
         if (!pblocktree->WriteBlockIndex(blockindex))
@@ -2059,10 +2064,11 @@ void static FindMostWorkChain() {
         CBlockIndex *pindexTest = pindexNew;
         bool fInvalidAncestor = false;
         while (pindexTest && !chainActive.Contains(pindexTest)) {
-            if (pindexTest->nStatus & BLOCK_FAILED_MASK) {
+            if (!pindexTest->IsValid(BLOCK_VALID_TRANSACTIONS) || !(pindexTest->nStatus & BLOCK_HAVE_DATA)) {
                 // Candidate has an invalid ancestor, remove entire chain from the set.
                 if (pindexBestInvalid == NULL || pindexNew->nChainWork > pindexBestInvalid->nChainWork)
-                    pindexBestInvalid = pindexNew;                CBlockIndex *pindexFailed = pindexNew;
+                    pindexBestInvalid = pindexNew;
+                CBlockIndex *pindexFailed = pindexNew;
                 while (pindexTest != pindexFailed) {
                     pindexFailed->nStatus |= BLOCK_FAILED_CHILD;
                     setBlockIndexValid.erase(pindexFailed);
@@ -2136,12 +2142,14 @@ bool ActivateBestChain(CValidationState &state) {
     return true;
 }
 
-bool AddToBlockIndex(CBlock& block, CValidationState& state, const CDiskBlockPos& pos)
+
+CBlockIndex* AddToBlockIndex(CBlockHeader& block)
 {
     // Check for duplicate
     uint256 hash = block.GetHash();
-    if (mapBlockIndex.count(hash))
-        return state.Invalid(error("AddToBlockIndex() : %s already exists", hash.ToString()), 0, "duplicate");
+    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(hash);
+    if (it != mapBlockIndex.end())
+        return it->second;
 
     // Construct new block index object
     CBlockIndex* pindexNew = new CBlockIndex(block);
@@ -2158,14 +2166,38 @@ bool AddToBlockIndex(CBlock& block, CValidationState& state, const CDiskBlockPos
         pindexNew->pprev = (*miPrev).second;
         pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
     }
-    pindexNew->nTx = block.vtx.size();
     pindexNew->nChainWork = (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) + pindexNew->GetBlockWork().getuint256();
-    pindexNew->nChainTx = (pindexNew->pprev ? pindexNew->pprev->nChainTx : 0) + pindexNew->nTx;
+    pindexNew->RaiseValidity(BLOCK_VALID_TREE);
+
+    return pindexNew;
+}
+
+
+// Mark a block as having its data received and checked (up to BLOCK_VALID_TRANSACTIONS).
+bool ReceivedBlockTransactions(const CBlock &block, CValidationState& state, CBlockIndex *pindexNew, const CDiskBlockPos& pos)
+{
+    pindexNew->nTx = block.vtx.size();
+    if (pindexNew->pprev) {
+        // Not the genesis block.
+        if (pindexNew->pprev->nChainTx) {
+            // This parent's block's total number transactions is known, so compute outs.
+            pindexNew->nChainTx = pindexNew->pprev->nChainTx + pindexNew->nTx;
+        } else {
+            // The total number of transactions isn't known yet.
+            // We will compute it when the block is connected.
+            pindexNew->nChainTx = 0;
+        }
+    } else {
+        // Genesis block.
+        pindexNew->nChainTx = pindexNew->nTx;
+    }
     pindexNew->nFile = pos.nFile;
     pindexNew->nDataPos = pos.nPos;
     pindexNew->nUndoPos = 0;
-    pindexNew->nStatus = BLOCK_VALID_TRANSACTIONS | BLOCK_HAVE_DATA;
-    setBlockIndexValid.insert(pindexNew);
+    pindexNew->nStatus |= BLOCK_HAVE_DATA;
+
+    if (pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS))
+        setBlockIndexValid.insert(pindexNew);
 
     if (!pblocktree->WriteBlockIndex(CDiskBlockIndex(pindexNew)))
         return state.Abort(_("Failed to write block index"));
@@ -2289,26 +2321,55 @@ bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos, unsigne
 }
 
 
+bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, bool fCheckPOW)
+{
+    // Check proof of work matches claimed amount
+    if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits))
+        return state.DoS(50, error("CheckBlockHeader() : proof of work failed"),
+                         REJECT_INVALID, "high-hash");
+
+    // Check timestamp
+    if (block.GetBlockTime() > GetAdjustedTime() + 2 * 60 * 60)
+        return state.Invalid(error("CheckBlockHeader() : block timestamp too far in the future"),
+                             REJECT_INVALID, "time-too-new");
+
+    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(mapBlockIndex);
+    if (pcheckpoint && block.hashPrevBlock != (chainActive.Tip() ? chainActive.Tip()->GetBlockHash() : uint256(0)))
+    {
+        // Extra checks to prevent "fill up memory by spamming with bogus blocks"
+        int64_t deltaTime = block.GetBlockTime() - pcheckpoint->nTime;
+        if (deltaTime < 0)
+        {
+            return state.DoS(100, error("CheckBlockHeader() : block with timestamp before last checkpoint"),
+                             REJECT_CHECKPOINT, "time-too-old");
+        }
+        CBigNum bnNewBlock;
+        bnNewBlock.SetCompact(block.nBits);
+        CBigNum bnRequired;
+        bnRequired.SetCompact(ComputeMinWork(pcheckpoint->nBits, deltaTime));
+        if (bnNewBlock > bnRequired)
+        {
+            return state.DoS(100, error("CheckBlockHeader() : block with too little proof-of-work"),
+                             REJECT_INVALID, "bad-diffbits");
+        }
+    }
+
+    return true;
+}
+
 bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW, bool fCheckMerkleRoot)
 {
     // These are checks that are independent of context
     // that can be verified before saving an orphan block.
 
+    if (!CheckBlockHeader(block, state, fCheckPOW))
+        return false;
+
     // Size limits
     if (block.vtx.empty() || block.vtx.size() > MAX_BLOCK_SIZE || ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION) > MAX_BLOCK_SIZE)
         return state.DoS(100, error("CheckBlock() : size limits failed"),
                          REJECT_INVALID, "bad-blk-length");
 
-    // Check proof of work matches claimed amount
-    if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits))
-        return state.DoS(50, error("CheckBlock() : proof of work failed"),
-                         REJECT_INVALID, "high-hash");
-
-    // Check timestamp
-    if (block.GetBlockTime() > GetAdjustedTime() + 2 * 60 * 60)
-        return state.Invalid(error("CheckBlock() : block timestamp too far in the future"),
-                             REJECT_INVALID, "time-too-new");
-
     // First transaction must be coinbase, the rest must not be
     if (block.vtx.empty() || !block.vtx[0].IsCoinBase())
         return state.DoS(100, error("CheckBlock() : first tx is not coinbase"),
@@ -2355,13 +2416,18 @@ bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW, bo
     return true;
 }
 
-bool AcceptBlock(CBlock& block, CValidationState& state, CDiskBlockPos* dbp)
+bool AcceptBlockHeader(CBlockHeader& block, CValidationState& state, CBlockIndex** ppindex)
 {
     AssertLockHeld(cs_main);
     // Check for duplicate
     uint256 hash = block.GetHash();
-    if (mapBlockIndex.count(hash))
-        return state.Invalid(error("AcceptBlock() : block already in mapBlockIndex"), 0, "duplicate");
+    std::map<uint256, CBlockIndex*>::iterator miSelf = mapBlockIndex.find(hash);
+    CBlockIndex *pindex = NULL;
+    if (miSelf != mapBlockIndex.end()) {
+        pindex = miSelf->second;
+        if (pindex->nStatus & BLOCK_FAILED_MASK)
+            return state.Invalid(error("AcceptBlock() : block is marked invalid"), 0, "duplicate");
+    }
 
     // Get prev block index
     CBlockIndex* pindexPrev = NULL;
@@ -2383,12 +2449,6 @@ bool AcceptBlock(CBlock& block, CValidationState& state, CDiskBlockPos* dbp)
             return state.Invalid(error("AcceptBlock() : block's timestamp is too early"),
                                  REJECT_INVALID, "time-too-old");
 
-        // Check that all transactions are finalized
-        BOOST_FOREACH(const CTransaction& tx, block.vtx)
-            if (!IsFinalTx(tx, nHeight, block.GetBlockTime()))
-                return state.DoS(10, error("AcceptBlock() : contains a non-final transaction"),
-                                 REJECT_INVALID, "bad-txns-nonfinal");
-
         // Check that the block chain matches the known block chain up to a checkpoint
         if (!Checkpoints::CheckBlock(nHeight, hash))
             return state.DoS(100, error("AcceptBlock() : rejected by checkpoint lock-in at %d", nHeight),
@@ -2409,18 +2469,57 @@ bool AcceptBlock(CBlock& block, CValidationState& state, CDiskBlockPos* dbp)
                                      REJECT_OBSOLETE, "bad-version");
             }
         }
-        // Enforce block.nVersion=2 rule that the coinbase starts with serialized block height
-        if (block.nVersion >= 2)
+    }
+
+    if (pindex == NULL)
+        pindex = AddToBlockIndex(block);
+
+    if (ppindex)
+        *ppindex = pindex;
+
+    return true;
+}
+
+bool AcceptBlock(CBlock& block, CValidationState& state, CBlockIndex** ppindex, CDiskBlockPos* dbp)
+{
+    AssertLockHeld(cs_main);
+
+    CBlockIndex *&pindex = *ppindex;
+
+    if (!AcceptBlockHeader(block, state, &pindex))
+        return false;
+
+    if (!CheckBlock(block, state)) {
+        if (state.Invalid() && !state.CorruptionPossible()) {
+            pindex->nStatus |= BLOCK_FAILED_VALID;
+        }
+        return false;
+    }
+
+    int nHeight = pindex->nHeight;
+    uint256 hash = pindex->GetBlockHash();
+
+    // Check that all transactions are finalized
+    BOOST_FOREACH(const CTransaction& tx, block.vtx)
+        if (!IsFinalTx(tx, nHeight, block.GetBlockTime())) {
+            pindex->nStatus |= BLOCK_FAILED_VALID;
+            return state.DoS(10, error("AcceptBlock() : contains a non-final transaction"),
+                             REJECT_INVALID, "bad-txns-nonfinal");
+        }
+
+    // Enforce block.nVersion=2 rule that the coinbase starts with serialized block height
+    if (block.nVersion >= 2)
+    {
+        // if 750 of the last 1,000 blocks are version 2 or greater (51/100 if testnet):
+        if ((!TestNet() && CBlockIndex::IsSuperMajority(2, pindex->pprev, 750, 1000)) ||
+            (TestNet() && CBlockIndex::IsSuperMajority(2, pindex->pprev, 51, 100)))
         {
-            // if 750 of the last 1,000 blocks are version 2 or greater (51/100 if testnet):
-            if ((!TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 750, 1000)) ||
-                (TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 51, 100)))
-            {
-                CScript expect = CScript() << nHeight;
-                if (block.vtx[0].vin[0].scriptSig.size() < expect.size() ||
-                    !std::equal(expect.begin(), expect.end(), block.vtx[0].vin[0].scriptSig.begin()))
-                    return state.DoS(100, error("AcceptBlock() : block height mismatch in coinbase"),
-                                     REJECT_INVALID, "bad-cb-height");
+            CScript expect = CScript() << nHeight;
+            if (block.vtx[0].vin[0].scriptSig.size() < expect.size() ||
+                !std::equal(expect.begin(), expect.end(), block.vtx[0].vin[0].scriptSig.begin())) {
+                pindex->nStatus |= BLOCK_FAILED_VALID;
+                return state.DoS(100, error("AcceptBlock() : block height mismatch in coinbase"),
+                                 REJECT_INVALID, "bad-cb-height");
             }
         }
     }
@@ -2436,8 +2535,8 @@ bool AcceptBlock(CBlock& block, CValidationState& state, CDiskBlockPos* dbp)
         if (dbp == NULL)
             if (!WriteBlockToDisk(block, blockPos))
                 return state.Abort(_("Failed to write block"));
-        if (!AddToBlockIndex(block, state, blockPos))
-            return error("AcceptBlock() : AddToBlockIndex failed");
+        if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
+            return error("AcceptBlock() : ReceivedBlockTransactions failed");
     } catch(std::runtime_error &e) {
         return state.Abort(_("System error: ") + e.what());
     }
@@ -2507,30 +2606,9 @@ bool ProcessBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDiskBl
     if (!CheckBlock(*pblock, state))
         return error("ProcessBlock() : CheckBlock FAILED");
 
-    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(mapBlockIndex);
-    if (pcheckpoint && pblock->hashPrevBlock != (chainActive.Tip() ? chainActive.Tip()->GetBlockHash() : uint256(0)))
-    {
-        // Extra checks to prevent "fill up memory by spamming with bogus blocks"
-        int64_t deltaTime = pblock->GetBlockTime() - pcheckpoint->nTime;
-        if (deltaTime < 0)
-        {
-            return state.DoS(100, error("ProcessBlock() : block with timestamp before last checkpoint"),
-                             REJECT_CHECKPOINT, "time-too-old");
-        }
-        CBigNum bnNewBlock;
-        bnNewBlock.SetCompact(pblock->nBits);
-        CBigNum bnRequired;
-        bnRequired.SetCompact(ComputeMinWork(pcheckpoint->nBits, deltaTime));
-        if (bnNewBlock > bnRequired)
-        {
-            return state.DoS(100, error("ProcessBlock() : block with too little proof-of-work"),
-                             REJECT_INVALID, "bad-diffbits");
-        }
-    }
-
-
-    // If we don't already have its previous block, shunt it off to holding area until we get it
-    if (pblock->hashPrevBlock != 0 && !mapBlockIndex.count(pblock->hashPrevBlock))
+    // If we don't already have its previous block (with full data), shunt it off to holding area until we get it
+    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(pblock->hashPrevBlock);
+    if (pblock->hashPrevBlock != 0 && (it == mapBlockIndex.end() || !(it->second->nStatus & BLOCK_HAVE_DATA)))
     {
         LogPrintf("ProcessBlock: ORPHAN BLOCK %lu, prev=%s\n", (unsigned long)mapOrphanBlocks.size(), pblock->hashPrevBlock.ToString());
 
@@ -2555,7 +2633,9 @@ bool ProcessBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDiskBl
     }
 
     // Store to disk
-    if (!AcceptBlock(*pblock, state, dbp))
+    CBlockIndex *pindex = NULL;
+    bool ret = AcceptBlock(*pblock, state, &pindex, dbp);
+    if (!ret)
         return error("ProcessBlock() : AcceptBlock FAILED");
 
     // Recursively process any orphan blocks that depended on this one
@@ -2576,7 +2656,8 @@ bool ProcessBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDiskBl
             block.BuildMerkleTree();
             // Use a dummy CValidationState so someone can't setup nodes to counter-DoS based on orphan resolution (that is, feeding people an invalid block based on LegitBlockX in order to get anyone relaying LegitBlockX banned)
             CValidationState stateDummy;
-            if (AcceptBlock(block, stateDummy))
+            CBlockIndex *pindexChild = NULL;
+            if (AcceptBlock(block, stateDummy, &pindexChild))
                 vWorkQueue.push_back(mi->second->hashBlock);
             mapOrphanBlocks.erase(mi->second->hashBlock);
             delete mi->second;
@@ -2839,7 +2920,7 @@ bool static LoadBlockIndexDB()
         CBlockIndex* pindex = item.second;
         pindex->nChainWork = (pindex->pprev ? pindex->pprev->nChainWork : 0) + pindex->GetBlockWork().getuint256();
         pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx;
-        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS && !(pindex->nStatus & BLOCK_FAILED_MASK))
+        if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS))
             setBlockIndexValid.insert(pindex);
         if (pindex->nStatus & BLOCK_FAILED_MASK && (!pindexBestInvalid || pindex->nChainWork > pindexBestInvalid->nChainWork))
             pindexBestInvalid = pindex;
@@ -2987,7 +3068,8 @@ bool InitBlockIndex() {
                 return error("LoadBlockIndex() : FindBlockPos failed");
             if (!WriteBlockToDisk(block, blockPos))
                 return error("LoadBlockIndex() : writing genesis block to disk failed");
-            if (!AddToBlockIndex(block, state, blockPos))
+            CBlockIndex *pindex = AddToBlockIndex(block);
+            if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
                 return error("LoadBlockIndex() : genesis block not accepted");
         } catch(std::runtime_error &e) {
             return error("LoadBlockIndex() : failed to initialize block database: %s", e.what());
diff --git a/src/main.h b/src/main.h
index 825e577d1e..f63f4d5f11 100644
--- a/src/main.h
+++ b/src/main.h
@@ -603,11 +603,13 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
 bool AddToBlockIndex(CBlock& block, CValidationState& state, const CDiskBlockPos& pos);
 
 // Context-independent validity checks
+bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, bool fCheckPOW = true);
 bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW = true, bool fCheckMerkleRoot = true);
 
 // Store block on disk
 // if dbp is provided, the file is known to already reside on disk
-bool AcceptBlock(CBlock& block, CValidationState& state, CDiskBlockPos* dbp = NULL);
+bool AcceptBlock(CBlock& block, CValidationState& state, CBlockIndex **pindex, CDiskBlockPos* dbp = NULL);
+bool AcceptBlockHeader(CBlockHeader& block, CValidationState& state, CBlockIndex **ppindex= NULL);
 
 
 
@@ -865,6 +867,29 @@ public:
     {
         LogPrintf("%s\n", ToString().c_str());
     }
+
+    // Check whether this block index entry is valid up to the passed validity level.
+    bool IsValid(enum BlockStatus nUpTo = BLOCK_VALID_TRANSACTIONS) const
+    {
+        assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed.
+        if (nStatus & BLOCK_FAILED_MASK)
+            return false;
+        return ((nStatus & BLOCK_VALID_MASK) >= nUpTo);
+    }
+
+    // Raise the validity level of this block index entry.
+    // Returns true if the validity was changed.
+    bool RaiseValidity(enum BlockStatus nUpTo)
+    {
+        assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed.
+        if (nStatus & BLOCK_FAILED_MASK)
+            return false;
+        if ((nStatus & BLOCK_VALID_MASK) < nUpTo) {
+            nStatus = (nStatus & ~BLOCK_VALID_MASK) | nUpTo;
+            return true;
+        }
+        return false;
+    }
 };