Use pnode->nLastRecv as sync score directly

NodeSyncScore() should find the node which we recv data most recently, so put a negative sign to pnode->nLastRecv is indeed wrong.

Also change the return value type to int64_t.

Signed-off-by: Huang Le <4tarhl@gmail.com>

src/net.cpp

@@ -1455,13 +1455,13 @@ bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOu
 
 // for now, use a very simple selection metric: the node from which we received
 // most recently
-double static NodeSyncScore(const CNode *pnode) {
-    return -pnode->nLastRecv;
+static int64_t NodeSyncScore(const CNode *pnode) {
+    return pnode->nLastRecv;
 }
 
 void static StartSync(const vector<CNode*> &vNodes) {
     CNode *pnodeNewSync = NULL;
-    double dBestScore = 0;
+    int64_t nBestScore = 0;
 
     int nBestHeight = g_signals.GetHeight().get_value_or(0);
 
@@ -1473,10 +1473,10 @@ void static StartSync(const vector<CNode*> &vNodes) {
             (pnode->nStartingHeight > (nBestHeight - 144)) &&
             (pnode->nVersion < NOBLKS_VERSION_START || pnode->nVersion >= NOBLKS_VERSION_END)) {
             // if ok, compare node's score with the best so far
-            double dScore = NodeSyncScore(pnode);
-            if (pnodeNewSync == NULL || dScore > dBestScore) {
+            int64_t nScore = NodeSyncScore(pnode);
+            if (pnodeNewSync == NULL || nScore > nBestScore) {
                 pnodeNewSync = pnode;
-                dBestScore = dScore;
+                nBestScore = nScore;
             }
         }
     }