From dce8360e44d5330cc9f9d09c9b09ac9237237204 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Thu, 19 Mar 2015 05:34:06 -0700 Subject: Reduce checkpoints' effect on consensus. Instead of only checking height to decide whether to disable script checks, actually check whether a block is an ancestor of a checkpoint, up to which headers have been validated. This means that we don't have to prevent accepting a side branch anymore - it will be safe, just less fast to do. We still need to prevent being fed a multitude of low-difficulty headers filling up our memory. The mechanism for that is unchanged for now: once a checkpoint is reached with headers, no headers chain branching off before that point are allowed anymore. --- src/main.cpp | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'src/main.cpp') diff --git a/src/main.cpp b/src/main.cpp index 4f4926eb40..39da3406a8 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -1714,7 +1714,14 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin return true; } - bool fScriptChecks = (!fCheckpointsEnabled || pindex->nHeight >= Checkpoints::GetTotalBlocksEstimate(chainparams.Checkpoints())); + bool fScriptChecks = true; + if (fCheckpointsEnabled) { + CBlockIndex *pindexLastCheckpoint = Checkpoints::GetLastCheckpoint(chainparams.Checkpoints()); + if (pindexLastCheckpoint && pindexLastCheckpoint->GetAncestor(pindex->nHeight) == pindex) { + // This block is an ancestor of a checkpoint: disable script checks + fScriptChecks = false; + } + } // Do not allow blocks that contain transactions which 'overwrite' older transactions, // unless those are already completely spent. @@ -2630,13 +2637,8 @@ bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& sta return state.Invalid(error("%s: block's timestamp is too early", __func__), REJECT_INVALID, "time-too-old"); - if(fCheckpointsEnabled) + if (fCheckpointsEnabled) { - // Check that the block chain matches the known block chain up to a checkpoint - if (!Checkpoints::CheckBlock(chainParams.Checkpoints(), nHeight, hash)) - return state.DoS(100, error("%s: rejected by checkpoint lock-in at %d", __func__, nHeight), - REJECT_CHECKPOINT, "checkpoint mismatch"); - // Don't accept any forks from the main chain prior to last checkpoint CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(chainParams.Checkpoints()); if (pcheckpoint && nHeight < pcheckpoint->nHeight) -- cgit v1.2.3