diff --git a/src/net_processing.cpp b/src/net_processing.cpp index e4d8d62a2..3a98b59b3 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -168,6 +168,8 @@ struct CNodeState { int nUnconnectingHeaders; //! Whether we've started headers synchronization with this peer. bool fSyncStarted; + //! When to potentially disconnect peer for stalling headers download + int64_t nHeadersSyncTimeout; //! Since when we're stalling block download progress (in microseconds), or 0. int64_t nStallingSince; std::list vBlocksInFlight; @@ -207,6 +209,7 @@ struct CNodeState { pindexBestHeaderSent = NULL; nUnconnectingHeaders = 0; fSyncStarted = false; + nHeadersSyncTimeout = 0; nStallingSince = 0; nDownloadingSince = 0; nBlocksInFlight = 0; @@ -2883,6 +2886,7 @@ bool SendMessages(CNode* pto, CConnman& connman, const std::atomic& interr // Only actively request headers from a single peer, unless we're close to today. if ((nSyncStarted == 0 && fFetch) || pindexBestHeader->GetBlockTime() > GetAdjustedTime() - 24 * 60 * 60) { state.fSyncStarted = true; + state.nHeadersSyncTimeout = GetTimeMicros() + HEADERS_DOWNLOAD_TIMEOUT_BASE + HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER * (GetAdjustedTime() - pindexBestHeader->GetBlockTime())/(consensusParams.nPowTargetSpacing); nSyncStarted++; const CBlockIndex *pindexStart = pindexBestHeader; /* If possible, start at the block preceding the currently @@ -3206,6 +3210,39 @@ bool SendMessages(CNode* pto, CConnman& connman, const std::atomic& interr return true; } } + // Check for headers sync timeouts + if (state.fSyncStarted && state.nHeadersSyncTimeout < std::numeric_limits::max()) { + // Detect whether this is a stalling initial-headers-sync peer + if (pindexBestHeader->GetBlockTime() <= GetAdjustedTime() - 24*60*60) { + if (nNow > state.nHeadersSyncTimeout && nSyncStarted == 1 && (nPreferredDownload - state.fPreferredDownload >= 1)) { + // Disconnect a (non-whitelisted) peer if it is our only sync peer, + // and we have others we could be using instead. + // Note: If all our peers are inbound, then we won't + // disconnect our sync peer for stalling; we have bigger + // problems if we can't get any outbound peers. + if (!pto->fWhitelisted) { + LogPrintf("Timeout downloading headers from peer=%d, disconnecting\n", pto->GetId()); + pto->fDisconnect = true; + return true; + } else { + LogPrintf("Timeout downloading headers from whitelisted peer=%d, not disconnecting\n", pto->GetId()); + // Reset the headers sync state so that we have a + // chance to try downloading from a different peer. + // Note: this will also result in at least one more + // getheaders message to be sent to + // this peer (eventually). + state.fSyncStarted = false; + nSyncStarted--; + state.nHeadersSyncTimeout = 0; + } + } + } else { + // After we've caught up once, reset the timeout so we can't trigger + // disconnect later. + state.nHeadersSyncTimeout = std::numeric_limits::max(); + } + } + // // Message: getdata (blocks) diff --git a/src/net_processing.h b/src/net_processing.h index f460595bc..db6d81e6b 100644 --- a/src/net_processing.h +++ b/src/net_processing.h @@ -17,6 +17,10 @@ static const int64_t ORPHAN_TX_EXPIRE_TIME = 20 * 60; static const int64_t ORPHAN_TX_EXPIRE_INTERVAL = 5 * 60; /** Default number of orphan+recently-replaced txn to keep around for block reconstruction */ static const unsigned int DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN = 100; +/** Headers download timeout expressed in microseconds + * Timeout = base + per_header * (expected number of headers) */ +static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_BASE = 15 * 60 * 1000000; // 15 minutes +static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER = 1000; // 1ms/header /** Register with a network node to receive its signals */ void RegisterNodeSignals(CNodeSignals& nodeSignals);