Merge #8054: net: Avoid duplicate getheaders requests.

f93c2a1 net: Avoid duplicate getheaders requests. (Daniel Kraft)
This commit is contained in:
Wladimir J. van der Laan 2016-05-18 12:28:07 +02:00
commit 8e8bebc040
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1 changed files with 8 additions and 1 deletions

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@ -5084,6 +5084,13 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
return true;
}
// If we already know the last header in the message, then it contains
// no new information for us. In this case, we do not request
// more headers later. This prevents multiple chains of redundant
// getheader requests from running in parallel if triggered by incoming
// blocks while the node is still in initial headers sync.
const bool hasNewHeaders = (mapBlockIndex.count(headers.back().GetHash()) == 0);
CBlockIndex *pindexLast = NULL;
BOOST_FOREACH(const CBlockHeader& header, headers) {
CValidationState state;
@ -5104,7 +5111,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
if (pindexLast)
UpdateBlockAvailability(pfrom->GetId(), pindexLast->GetBlockHash());
if (nCount == MAX_HEADERS_RESULTS && pindexLast) {
if (nCount == MAX_HEADERS_RESULTS && pindexLast && hasNewHeaders) {
// 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.