DGW v2 implementation with timewarp limitations

dashpay · Mar 25, 2014 · 857e34d · 857e34d
1 parent 0f2c10e
commit 857e34d
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Showing 2 changed files with 113 additions and 6 deletions.
diff --git a/src/main.cpp b/src/main.cpp
@@ -1345,6 +1345,82 @@ unsigned int static DarkGravityWave(const CBlockIndex* pindexLast, const CBlockH
     return bnNew.GetCompact();
 }
 
+unsigned int static DarkGravityWave2(const CBlockIndex* pindexLast, const CBlockHeader *pblock) {
+    /* current difficulty formula, darkcoin - DarkGravity v2, written by Evan Duffield - evan@darkcoin.io */
+    const CBlockIndex *BlockLastSolved = pindexLast;
+    const CBlockIndex *BlockReading = pindexLast;
+    const CBlockHeader *BlockCreating = pblock;
+    BlockCreating = BlockCreating;
+    int64 nBlockTimeAverage = 0;
+    int64 nBlockTimeAveragePrev = 0;
+    int64 nBlockTimeCount = 0;
+    int64 nBlockTimeSum2 = 0;
+    int64 nBlockTimeCount2 = 0;
+    int64 LastBlockTime = 0;
+    int64 PastBlocksMin = 14;
+    int64 PastBlocksMax = 140;
+    int64 CountBlocks = 0;
+    CBigNum PastDifficultyAverage;
+    CBigNum PastDifficultyAveragePrev;
+
+    if (BlockLastSolved == NULL || BlockLastSolved->nHeight == 0 || BlockLastSolved->nHeight < PastBlocksMin) { return bnProofOfWorkLimit.GetCompact(); }
+
+    for (unsigned int i = 1; BlockReading && BlockReading->nHeight > 0; i++) {
+        if (PastBlocksMax > 0 && i > PastBlocksMax) { break; }
+        CountBlocks++;
+
+        if(CountBlocks <= PastBlocksMin) {
+            if (CountBlocks == 1) { PastDifficultyAverage.SetCompact(BlockReading->nBits); }
+            else { PastDifficultyAverage = ((CBigNum().SetCompact(BlockReading->nBits) - PastDifficultyAveragePrev) / CountBlocks) + PastDifficultyAveragePrev; }
+            PastDifficultyAveragePrev = PastDifficultyAverage;
+        }
+
+        if(LastBlockTime > 0){
+            int64 Diff = (LastBlockTime - BlockReading->GetBlockTime());
+            if(nBlockTimeCount <= PastBlocksMin) {
+                nBlockTimeCount++;
+
+                if (nBlockTimeCount == 1) { nBlockTimeAverage = Diff; }
+                else { nBlockTimeAverage = ((Diff - nBlockTimeAveragePrev) / nBlockTimeCount) + nBlockTimeAveragePrev; }
+                nBlockTimeAveragePrev = nBlockTimeAverage;
+            }
+            nBlockTimeCount2++;
+            nBlockTimeSum2 += Diff;
+        }
+        LastBlockTime = BlockReading->GetBlockTime();      
+
+        if (BlockReading->pprev == NULL) { assert(BlockReading); break; }
+        BlockReading = BlockReading->pprev;
+    }
+
+    CBigNum bnNew(PastDifficultyAverage);
+    if (nBlockTimeCount != 0 && nBlockTimeCount2 != 0) {
+            double SmartAverage = ((((long double)nBlockTimeAverage)*0.7)+(((long double)nBlockTimeSum2 / (long double)nBlockTimeCount2)*0.3));
+            if(SmartAverage < 1) SmartAverage = 1;
+            double Shift = nTargetSpacing/SmartAverage;
+
+            double fActualTimespan = ((long double)CountBlocks*(double)nTargetSpacing)/Shift;
+            double fTargetTimespan = ((long double)CountBlocks*(double)nTargetSpacing);
+
+            if (fActualTimespan < fTargetTimespan/3)
+                fActualTimespan = fTargetTimespan/3;
+            if (fActualTimespan > fTargetTimespan*3)
+                fActualTimespan = fTargetTimespan*3;
+
+            int64 nActualTimespan = fActualTimespan;
+            int64 nTargetTimespan = fTargetTimespan;
+
+            // Retarget
+            bnNew *= nActualTimespan;
+            bnNew /= nTargetTimespan;
+    }
+
+    if (bnNew > bnProofOfWorkLimit){
+        bnNew = bnProofOfWorkLimit;
+    }
+
+    return bnNew.GetCompact();
+}
 
 unsigned int static GetNextWorkRequired_V2(const CBlockIndex* pindexLast, const CBlockHeader *pblock)
 {
@@ -1362,17 +1438,20 @@ unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast, const CBl
 {
         int DiffMode = 1;
         if (fTestNet) {
-                if (pindexLast->nHeight+1 >= 5) { DiffMode = 3; }
+                if (pindexLast->nHeight+1 >= 15) { DiffMode = 4; }
+                else if (pindexLast->nHeight+1 >= 5) { DiffMode = 3; }
         }
         else {
-                if (pindexLast->nHeight+1 >= 34140) { DiffMode = 3; }
+                if (pindexLast->nHeight+1 >= 45000) { DiffMode = 4; }
+                else if (pindexLast->nHeight+1 >= 34140) { DiffMode = 3; }
                 else if (pindexLast->nHeight+1 >= 15200) { DiffMode = 2; }
         }
 
         if (DiffMode == 1) { return GetNextWorkRequired_V1(pindexLast, pblock); }
         else if (DiffMode == 2) { return GetNextWorkRequired_V2(pindexLast, pblock); }
         else if (DiffMode == 3) { return DarkGravityWave(pindexLast, pblock); }
-        return DarkGravityWave(pindexLast, pblock);
+        else if (DiffMode == 4) { return DarkGravityWave2(pindexLast, pblock); }
+        return DarkGravityWave2(pindexLast, pblock);
 }
 
 
@@ -2367,9 +2446,37 @@ bool CBlock::AcceptBlock(CValidationState &state, CDiskBlockPos *dbp)
         pindexPrev = (*mi).second;
         nHeight = pindexPrev->nHeight+1;
 
+
         // Check proof of work
-        if (nBits != GetNextWorkRequired(pindexPrev, this))
-            return state.DoS(100, error("AcceptBlock() : incorrect proof of work"));
+        /*        
+        if(nHeight >= 34140 && nHeight <= 45000){
+            unsigned int nBitsNext = GetNextWorkRequired(pindexPrev, this);
+            unsigned int a = 0;
+            if(nBits > nBitsNext) a = nBits - nBitsNext;
+            else if (nBits < nBitsNext) a = nBitsNext - nBits;
+            printf(" !--- %u %u, %u \n", nBits, nBitsNext, a);
+            double n1 = ConvertBitsToDouble(nBits);
+            double n2 = ConvertBitsToDouble(nBitsNext);
+            printf(" !--- %f %f, %f \n", n1, n2, n1-n2);
+            if (abs(n1-n2) > 5)
+                return state.DoS(100, error("AcceptBlock() : incorrect proof of work (DGW pre-fork)"));
+        } else {*/
+            if (nBits != GetNextWorkRequired(pindexPrev, this))
+                return state.DoS(100, error("AcceptBlock() : incorrect proof of work"));
+        //}
+
+
+        // Prevent blocks from too far in the future
+        if(fTestNet || nHeight >= 45000){
+            if (GetBlockTime() > GetAdjustedTime() + 15 * 60) {
+                return error("AcceptBlock() : block's timestamp too far in the future");
+            }
+
+            // Check timestamp is not too far in the past
+            if (GetBlockTime() <= pindexPrev->GetBlockTime() - 15 * 60) {
+                return error("AcceptBlock() : block's timestamp is too early compare to last block");
+            }
+        }
 
         // Check timestamp against prev
         if (GetBlockTime() <= pindexPrev->GetMedianTimePast())

diff --git a/src/util.cpp b/src/util.cpp
@@ -1336,7 +1336,7 @@ void AddTimeData(const CNetAddr& ip, int64 nTime)
         int64 nMedian = vTimeOffsets.median();
         std::vector<int64> vSorted = vTimeOffsets.sorted();
         // Only let other nodes change our time by so much
-        if (abs64(nMedian) < 35 * 60) // DarkCoin: changed maximum adjust to 35 mins to avoid letting peers change our time too much in case of an attack.
+        if (abs64(nMedian) < 14 * 60) // DarkCoin: changed maximum adjust to 35 mins to avoid letting peers change our time too much in case of an attack.
         {
             nTimeOffset = nMedian;
         }