Increase block download timeout base from 10 to 20 minutes.

This harmonizes the block fetch timeout with the existing ping timeout
 and eliminates a guaranteed eventual failure from congestion collapse
 for a network operating right at its limit.

It's unlikely that we wouldn't suffer other failures if we were really
 anywhere near the network's limit, and a complete avoidance of congestion
 collapse risk requires (I think) an exponential back-off. So this isn't
 a major concern, but I think it's also useful for reducing the complexity
 of understanding out timeouts.

Github-Pull: #5647
Rebased-From: 3ff735c99a
This commit is contained in:
Gregory Maxwell 2015-01-12 09:53:10 -08:00 committed by Wladimir J. van der Laan
parent 336f9fbd30
commit 1eb14af28f
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@ -4516,12 +4516,12 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
LogPrintf("Peer=%d is stalling block download, disconnecting\n", pto->id);
pto->fDisconnect = true;
}
// In case there is a block that has been in flight from this peer for (1 + 0.5 * N) times the block interval
// In case there is a block that has been in flight from this peer for (2 + 0.5 * N) times the block interval
// (with N the number of validated blocks that were in flight at the time it was requested), disconnect due to
// timeout. We compensate for in-flight blocks to prevent killing off peers due to our own downstream link
// being saturated. We only count validated in-flight blocks so peers can't advertize nonexisting block hashes
// to unreasonably increase our timeout.
if (!pto->fDisconnect && state.vBlocksInFlight.size() > 0 && state.vBlocksInFlight.front().nTime < nNow - 500000 * Params().TargetSpacing() * (2 + state.vBlocksInFlight.front().nValidatedQueuedBefore)) {
if (!pto->fDisconnect && state.vBlocksInFlight.size() > 0 && state.vBlocksInFlight.front().nTime < nNow - 500000 * Params().TargetSpacing() * (4 + state.vBlocksInFlight.front().nValidatedQueuedBefore)) {
LogPrintf("Timeout downloading block %s from peer=%d, disconnecting\n", state.vBlocksInFlight.front().hash.ToString(), pto->id);
pto->fDisconnect = true;
}