Fix issue #848 : broken mining on testnet

[novacoin.git] / src / main.cpp

diff --git a/src/main.cpp b/src/main.cpp
index 9f12829..ebf51ae 100644 (file)
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -159,13 +159,14 @@ void static ResendWalletTransactions()
 // mapOrphanTransactions
 //
 
-void static AddOrphanTx(const CDataStream& vMsg)
+void AddOrphanTx(const CDataStream& vMsg)
 {
     CTransaction tx;
     CDataStream(vMsg) >> tx;
     uint256 hash = tx.GetHash();
     if (mapOrphanTransactions.count(hash))
         return;
+
     CDataStream* pvMsg = mapOrphanTransactions[hash] = new CDataStream(vMsg);
     BOOST_FOREACH(const CTxIn& txin, tx.vin)
         mapOrphanTransactionsByPrev.insert(make_pair(txin.prevout.hash, pvMsg));
@@ -193,6 +194,23 @@ void static EraseOrphanTx(uint256 hash)
     mapOrphanTransactions.erase(hash);
 }
 
+int LimitOrphanTxSize(int nMaxOrphans)
+{
+    int nEvicted = 0;
+    while (mapOrphanTransactions.size() > nMaxOrphans)
+    {
+        // Evict a random orphan:
+        std::vector<unsigned char> randbytes(32);
+        RAND_bytes(&randbytes[0], 32);
+        uint256 randomhash(randbytes);
+        map<uint256, CDataStream*>::iterator it = mapOrphanTransactions.lower_bound(randomhash);
+        if (it == mapOrphanTransactions.end())
+            it = mapOrphanTransactions.begin();
+        EraseOrphanTx(it->first);
+        ++nEvicted;
+    }
+    return nEvicted;
+}
 
 
 
@@ -789,6 +807,15 @@ void static InvalidChainFound(CBlockIndex* pindexNew)
         printf("InvalidChainFound: WARNING: Displayed transactions may not be correct!  You may need to upgrade, or other nodes may need to upgrade.\n");
 }
 
+void CBlock::UpdateTime(const CBlockIndex* pindexPrev)
+{
+    nTime = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
+
+    // Updating time can change work required on testnet:
+    if (fTestNet)
+        nBits = GetNextWorkRequired(pindexPrev, this);
+}
+
 
 
 
@@ -826,8 +853,10 @@ bool CTransaction::DisconnectInputs(CTxDB& txdb)
     }
 
     // Remove transaction from index
-    if (!txdb.EraseTxIndex(*this))
-        return error("DisconnectInputs() : EraseTxPos failed");
+    // This can fail if a duplicate of this transaction was in a chain that got
+    // reorganized away. This is only possible if this transaction was completely
+    // spent, so erasing it would be a no-op anway.
+    txdb.EraseTxIndex(*this);
 
     return true;
 }
@@ -1028,6 +1057,26 @@ bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex)
     if (!CheckBlock())
         return false;
 
+    // Do not allow blocks that contain transactions which 'overwrite' older transactions,
+    // unless those are already completely spent.
+    // If such overwrites are allowed, coinbases and transactions depending upon those
+    // can be duplicated to remove the ability to spend the first instance -- even after
+    // being sent to another address.
+    // See BIP30 and http://r6.ca/blog/20120206T005236Z.html for more information.
+    // This logic is not necessary for memory pool transactions, as AcceptToMemoryPool
+    // already refuses previously-known transaction id's entirely.
+    // This rule applies to all blocks whose timestamp is after March 15, 2012, 0:00 UTC.
+    // On testnet it is enabled as of februari 20, 2012, 0:00 UTC.
+    if (pindex->nTime > 1331769600 || (fTestNet && pindex->nTime > 1329696000))
+        BOOST_FOREACH(CTransaction& tx, vtx)
+        {
+            CTxIndex txindexOld;
+            if (txdb.ReadTxIndex(tx.GetHash(), txindexOld))
+                BOOST_FOREACH(CDiskTxPos &pos, txindexOld.vSpent)
+                    if (pos.IsNull())
+                        return false;
+        }
+
     //// issue here: it doesn't know the version
     unsigned int nTxPos = pindex->nBlockPos + ::GetSerializeSize(CBlock(), SER_DISK) - 1 + GetSizeOfCompactSize(vtx.size());
 
@@ -1881,7 +1930,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         }
 
         // Ask the first connected node for block updates
-        static int nAskedForBlocks;
+        static int nAskedForBlocks = 0;
         if (!pfrom->fClient &&
             (pfrom->nVersion < 32000 || pfrom->nVersion >= 32400) &&
              (nAskedForBlocks < 1 || vNodes.size() <= 1))
@@ -2183,6 +2232,11 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         {
             printf("storing orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
             AddOrphanTx(vMsg);
+
+            // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
+            int nEvicted = LimitOrphanTxSize(MAX_ORPHAN_TRANSACTIONS);
+            if (nEvicted > 0)
+                printf("mapOrphan overflow, removed %d tx\n", nEvicted);
         }
     }
 
@@ -2851,7 +2905,7 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
     // Fill in header
     pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
     pblock->hashMerkleRoot = pblock->BuildMerkleTree();
-    pblock->nTime          = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
+    pblock->UpdateTime(pindexPrev);
     pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock.get());
     pblock->nNonce         = 0;
 
@@ -3008,6 +3062,7 @@ void static BitcoinMiner(CWallet *pwallet)
         FormatHashBuffers(pblock.get(), pmidstate, pdata, phash1);
 
         unsigned int& nBlockTime = *(unsigned int*)(pdata + 64 + 4);
+        unsigned int& nBlockBits = *(unsigned int*)(pdata + 64 + 8);
         unsigned int& nBlockNonce = *(unsigned int*)(pdata + 64 + 12);
 
 
@@ -3095,8 +3150,14 @@ void static BitcoinMiner(CWallet *pwallet)
                 break;
 
             // Update nTime every few seconds
-            pblock->nTime = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
+            pblock->UpdateTime(pindexPrev);
             nBlockTime = ByteReverse(pblock->nTime);
+            if (fTestNet)
+            {
+                // Changing pblock->nTime can change work required on testnet:
+                nBlockBits = ByteReverse(pblock->nBits);
+                hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
+            }
         }
     }
 }