Implement BIP 14 : separate protocol version from client version

[novacoin.git] / src / main.cpp

diff --git a/src/main.cpp b/src/main.cpp
index 832a0f9..1da28d4 100644 (file)
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -17,6 +17,11 @@ using namespace boost;
 // Global state
 //
 
+// Name of client reported in the 'version' message. Report the same name
+// for both bitcoind and bitcoin-qt, to make it harder for attackers to
+// target servers or GUI users specifically.
+const std::string CLIENT_NAME("bitcoin-qt");
+
 CCriticalSection cs_setpwalletRegistered;
 set<CWallet*> setpwalletRegistered;
 
@@ -659,11 +664,32 @@ int64 static GetBlockValue(int nHeight, int64 nFees)
     return nSubsidy + nFees;
 }
 
+static const int64 nTargetTimespan = 14 * 24 * 60 * 60; // two weeks
+static const int64 nTargetSpacing = 10 * 60;
+static const int64 nInterval = nTargetTimespan / nTargetSpacing;
+
+//
+// minimum amount of work that could possibly be required nTime after
+// minimum work required was nBase
+//
+unsigned int ComputeMinWork(unsigned int nBase, int64 nTime)
+{
+    CBigNum bnResult;
+    bnResult.SetCompact(nBase);
+    while (nTime > 0 && bnResult < bnProofOfWorkLimit)
+    {
+        // Maximum 400% adjustment...
+        bnResult *= 4;
+        // ... in best-case exactly 4-times-normal target time
+        nTime -= nTargetTimespan*4;
+    }
+    if (bnResult > bnProofOfWorkLimit)
+        bnResult = bnProofOfWorkLimit;
+    return bnResult.GetCompact();
+}
+
 unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast)
 {
-    const int64 nTargetTimespan = 14 * 24 * 60 * 60; // two weeks
-    const int64 nTargetSpacing = 10 * 60;
-    const int64 nInterval = nTargetTimespan / nTargetSpacing;
 
     // Genesis block
     if (pindexLast == NULL)
@@ -1340,6 +1366,28 @@ bool ProcessBlock(CNode* pfrom, CBlock* pblock)
     if (!pblock->CheckBlock())
         return error("ProcessBlock() : CheckBlock FAILED");
 
+    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(mapBlockIndex);
+    if (pcheckpoint && pblock->hashPrevBlock != hashBestChain)
+    {
+        // Extra checks to prevent "fill up memory by spamming with bogus blocks"
+        int64 deltaTime = pblock->GetBlockTime() - pcheckpoint->nTime;
+        if (deltaTime < 0)
+        {
+            pfrom->Misbehaving(100);
+            return error("ProcessBlock() : block with timestamp before last checkpoint");
+        }
+        CBigNum bnNewBlock;
+        bnNewBlock.SetCompact(pblock->nBits);
+        CBigNum bnRequired;
+        bnRequired.SetCompact(ComputeMinWork(pcheckpoint->nBits, deltaTime));
+        if (bnNewBlock > bnRequired)
+        {
+            pfrom->Misbehaving(100);
+            return error("ProcessBlock() : block with too little proof-of-work");
+        }
+    }
+
+
     // If don't already have its previous block, shunt it off to holding area until we get it
     if (!mapBlockIndex.count(pblock->hashPrevBlock))
     {
@@ -1804,9 +1852,9 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         // Change version
         if (pfrom->nVersion >= 209)
             pfrom->PushMessage("verack");
-        pfrom->vSend.SetVersion(min(pfrom->nVersion, VERSION));
+        pfrom->vSend.SetVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
         if (pfrom->nVersion < 209)
-            pfrom->vRecv.SetVersion(min(pfrom->nVersion, VERSION));
+            pfrom->vRecv.SetVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
 
         if (!pfrom->fInbound)
         {
@@ -1859,7 +1907,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
 
     else if (strCommand == "verack")
     {
-        pfrom->vRecv.SetVersion(min(pfrom->nVersion, VERSION));
+        pfrom->vRecv.SetVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
     }