revert (#78) & fix: disabled more getheaders (#126)

* revert&fix: disabled more getheaders
* remove: printf

src/net_processing.cpp

@@ -1398,16 +1398,14 @@ bool static ProcessHeadersMessage(CNode *pfrom, CConnman *connman, const std::ve
         }
 
         // FIXME.SUGAR
-        // 120x bitcoin // IBD: disable additional download during IBD, due to too much traffic
-        /*
-        if (nCount == MAX_HEADERS_RESULTS) {
+        // IBD: reduce frequency of additional downloading during IBD, against too much traffic
+        if (nCount == MAX_HEADERS_RESULTS && (pindexLast->nHeight) % (MAX_HEADERS_RESULTS * 2) == 0) {
             // Headers message had its maximum size; the peer may have more headers.
             // TODO: optimize: if pindexLast is an ancestor of chainActive.Tip or pindexBestHeader, continue
             // from there instead.
             LogPrint(BCLog::NET, "more getheaders (%d) to end to peer=%d (startheight:%d)\n", pindexLast->nHeight, pfrom->GetId(), pfrom->nStartingHeight);
             connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexLast), uint256()));
         }
-        */
 
         bool fCanDirectFetch = CanDirectFetch(chainparams.GetConsensus());
         // If this set of headers is valid and ends in a block with at least as