diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/main.cpp | 38 | ||||
| -rw-r--r-- | src/main.h | 3 |
2 files changed, 40 insertions, 1 deletions
diff --git a/src/main.cpp b/src/main.cpp index 62f1cd1517..73fbe53afb 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -276,6 +276,8 @@ struct CNodeState { CBlockIndex *pindexLastCommonBlock; //! The best header we have sent our peer. CBlockIndex *pindexBestHeaderSent; + //! Length of current-streak of unconnecting headers announcements + int nUnconnectingHeaders; //! Whether we've started headers synchronization with this peer. bool fSyncStarted; //! Since when we're stalling block download progress (in microseconds), or 0. @@ -304,6 +306,7 @@ struct CNodeState { hashLastUnknownBlock.SetNull(); pindexLastCommonBlock = NULL; pindexBestHeaderSent = NULL; + nUnconnectingHeaders = 0; fSyncStarted = false; nStallingSince = 0; nDownloadingSince = 0; @@ -5773,6 +5776,35 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv, return true; } + CNodeState *nodestate = State(pfrom->GetId()); + + // If this looks like it could be a block announcement (nCount < + // MAX_BLOCKS_TO_ANNOUNCE), use special logic for handling headers that + // don't connect: + // - Send a getheaders message in response to try to connect the chain. + // - The peer can send up to MAX_UNCONNECTING_HEADERS in a row that + // don't connect before giving DoS points + // - Once a headers message is received that is valid and does connect, + // nUnconnectingHeaders gets reset back to 0. + if (mapBlockIndex.find(headers[0].hashPrevBlock) == mapBlockIndex.end() && nCount < MAX_BLOCKS_TO_ANNOUNCE) { + nodestate->nUnconnectingHeaders++; + pfrom->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), uint256()); + LogPrint("net", "received header %s: missing prev block %s, sending getheaders (%d) to end (peer=%d, nUnconnectingHeaders=%d)\n", + headers[0].GetHash().ToString(), + headers[0].hashPrevBlock.ToString(), + pindexBestHeader->nHeight, + pfrom->id, nodestate->nUnconnectingHeaders); + // Set hashLastUnknownBlock for this peer, so that if we + // eventually get the headers - even from a different peer - + // we can use this peer to download. + UpdateBlockAvailability(pfrom->GetId(), headers.back().GetHash()); + + if (nodestate->nUnconnectingHeaders % MAX_UNCONNECTING_HEADERS == 0) { + Misbehaving(pfrom->GetId(), 20); + } + return true; + } + CBlockIndex *pindexLast = NULL; BOOST_FOREACH(const CBlockHeader& header, headers) { CValidationState state; @@ -5790,6 +5822,11 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv, } } + if (nodestate->nUnconnectingHeaders > 0) { + LogPrint("net", "peer=%d: resetting nUnconnectingHeaders (%d -> 0)\n", pfrom->id, nodestate->nUnconnectingHeaders); + } + nodestate->nUnconnectingHeaders = 0; + assert(pindexLast); UpdateBlockAvailability(pfrom->GetId(), pindexLast->GetBlockHash()); @@ -5802,7 +5839,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv, } bool fCanDirectFetch = CanDirectFetch(chainparams.GetConsensus()); - CNodeState *nodestate = State(pfrom->GetId()); // If this set of headers is valid and ends in a block with at least as // much work as our tip, download as much as possible. if (fCanDirectFetch && pindexLast->IsValid(BLOCK_VALID_TREE) && chainActive.Tip()->nChainWork <= pindexLast->nChainWork) { diff --git a/src/main.h b/src/main.h index 7ea570d859..65ae2488f9 100644 --- a/src/main.h +++ b/src/main.h @@ -138,6 +138,9 @@ static const bool DEFAULT_FEEFILTER = true; /** Maximum number of headers to announce when relaying blocks with headers message.*/ static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8; +/** Maximum number of unconnecting headers announcements before DoS score */ +static const int MAX_UNCONNECTING_HEADERS = 10; + static const bool DEFAULT_PEERBLOOMFILTERS = true; struct BlockHasher |