Increased block download timeout for RegTest as CN hashing is slower and take more time.

Fixed deserialization of cn header in python test framework.

src/net_processing.cpp

@@ -3561,7 +3561,9 @@ bool PeerLogicValidation::SendMessages(CNode* pto, std::atomic<bool>& interruptM
         if (state.vBlocksInFlight.size() > 0) {
             QueuedBlock &queuedBlock = state.vBlocksInFlight.front();
             int nOtherPeersWithValidatedDownloads = nPeersWithValidatedDownloads - (state.nBlocksInFlightValidHeaders > 0);
-            if (nNow > state.nDownloadingSince + consensusParams.nPowTargetSpacing * (BLOCK_DOWNLOAD_TIMEOUT_BASE + BLOCK_DOWNLOAD_TIMEOUT_PER_PEER * nOtherPeersWithValidatedDownloads)) {
+            // Increase the block downloading timeout for RegTest, as Cryptonight hashing takes more time.
+            int64_t powTargetSpacing = (consensusParams.nPowTargetSpacing == 20) ? 40 : consensusParams.nPowTargetSpacing;
+            if (nNow > state.nDownloadingSince + powTargetSpacing * (BLOCK_DOWNLOAD_TIMEOUT_BASE + BLOCK_DOWNLOAD_TIMEOUT_PER_PEER * nOtherPeersWithValidatedDownloads)) {
                 LogPrintf("Timeout downloading block %s from peer=%d, disconnecting\n", queuedBlock.hash.ToString(), pto->GetId());
                 pto->fDisconnect = true;
                 return true;

test/functional/test_framework/messages.py

@@ -570,7 +570,8 @@ class CBlockHeader():
         self.nNonce = struct.unpack("<I", f.read(4))[0]
 
         # Cryptonote header
-        cnHeader = deser_string(f)
+        # Skip the length value
+        deser_compact_size(f)
         self.major_version = struct.unpack("<B", f.read(1))[0]
         self.minor_version = struct.unpack("<B", f.read(1))[0]
         self.timestamp = deser_varint(f)
@@ -637,7 +638,7 @@ class CBlockHeader():
             # self.sha256 stores the cn_fast hash.
             self.sha256 = uint256_from_str(pycryptonight.cn_fast_hash(c))
             self.hash = encode(pycryptonight.cn_fast_hash(c)[::-1], 'hex_codec').decode('ascii')
-            # 4 is variant 4. nNonce is used to store block height.
+            # nNonce is used to store block height.
             self.scrypt256 = uint256_from_str(pycryptonight.cn_slow_hash(c, self.major_version - 6, 0, self.nNonce))
 
     def rehash(self):