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Accept unrequested blocks with work equal to our tip

This is a simple change that makes our accept requirements the
same as our request requirements, (ever so slightly) further
decoupling our consensus logic from our FindNextBlocksToDownload
logic in net_processing.

Github-Pull: #11531
Rebased-From: 932f118e6a
tags/v0.15.1
Matt Corallo 3 years ago
parent
commit
51001d684b
2 changed files with 5 additions and 8 deletions
  1. 4
    4
      src/validation.cpp
  2. 1
    4
      test/functional/p2p-acceptblock.py

+ 4
- 4
src/validation.cpp View File

@@ -3102,7 +3102,7 @@ static bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CValidation
// process an unrequested block if it's new and has enough work to
// advance our tip, and isn't too many blocks ahead.
bool fAlreadyHave = pindex->nStatus & BLOCK_HAVE_DATA;
bool fHasMoreWork = (chainActive.Tip() ? pindex->nChainWork > chainActive.Tip()->nChainWork : true);
bool fHasMoreOrSameWork = (chainActive.Tip() ? pindex->nChainWork >= chainActive.Tip()->nChainWork : true);
// Blocks that are too out-of-order needlessly limit the effectiveness of
// pruning, because pruning will not delete block files that contain any
// blocks which are too close in height to the tip. Apply this test
@@ -3119,9 +3119,9 @@ static bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CValidation
// and unrequested blocks.
if (fAlreadyHave) return true;
if (!fRequested) { // If we didn't ask for it:
if (pindex->nTx != 0) return true; // This is a previously-processed block that was pruned
if (!fHasMoreWork) return true; // Don't process less-work chains
if (fTooFarAhead) return true; // Block height is too high
if (pindex->nTx != 0) return true; // This is a previously-processed block that was pruned
if (!fHasMoreOrSameWork) return true; // Don't process less-work chains
if (fTooFarAhead) return true; // Block height is too high

// Protect against DoS attacks from low-work chains.
// If our tip is behind, a peer could try to send us

+ 1
- 4
test/functional/p2p-acceptblock.py View File

@@ -142,8 +142,7 @@ class AcceptBlockTest(BitcoinTestFramework):
assert(tip_entry_found)

# But this block should be accepted by node since it has equal work.
# TODO: We currently drop this block but likely shouldn't
#self.nodes[0].getblock(block_h2f.hash)
self.nodes[0].getblock(block_h2f.hash)
self.log.info("Second height 2 block accepted, but not reorg'ed to")

# 4b. Now send another block that builds on the forking chain.
@@ -215,7 +214,6 @@ class AcceptBlockTest(BitcoinTestFramework):

test_node.wait_for_verack()
test_node.send_message(msg_block(block_h1f))
test_node.send_message(msg_block(block_h2f)) # This should not be required

test_node.sync_with_ping()
assert_equal(self.nodes[0].getblockcount(), 2)
@@ -239,7 +237,6 @@ class AcceptBlockTest(BitcoinTestFramework):

# 7. Send the missing block for the third time (now it is requested)
test_node.send_message(msg_block(block_h1f))
test_node.send_message(msg_block(block_h2f)) # This should not be required

test_node.sync_with_ping()
assert_equal(self.nodes[0].getblockcount(), 290)

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