From fe04a2045c3080797c6f93bf7cd2e12192b8f68f Mon Sep 17 00:00:00 2001 From: Bitflash Date: Sun, 2 Aug 2026 11:04:00 -0300 Subject: Add consensus block size limit (#111, from #110) CheckBlock() validated block size against MAX_SIZE, the serializer's generic 32 MB guard rather than a block rule; MAX_BLOCK_SIZE did not exist in this tree at all, because Bitcoin's 1 MB cap arrived in 0.3.x, after the 0.1.0 this fork came from. A miner could produce a 32 MB block and every node would download, verify and store it. Original work by mtg0001 in #110, rebased over #109 with the self-test conflict resolved, plus a comment explaining why the inherited count-against-bytes test stays. Measured before choosing the number: 5709 blocks read from blk0001.dat give a largest block of 34,290 bytes and a median of 216, so 1 MB leaves 29x of headroom and rejects nothing that exists. A node built from this branch then synced genesis to 5706 on the live network with zero size-limit rejections and zero CheckBlock errors -- the same test that caught BIP30 rejecting a real block at height 859. --- src/main.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'src/main.h') diff --git a/src/main.h b/src/main.h index 1b0be59..768f1c7 100644 --- a/src/main.h +++ b/src/main.h @@ -29,6 +29,10 @@ static const unsigned int MAX_ORPHAN_BLOCKS = 200; // so a block within the size limit could still hold millions of them and take // the network minutes of CPU to reject. Same value Bitcoin settled on. static const unsigned int MAX_BLOCK_SIGOPS = 20000; +// Consensus block-size ceiling. MAX_SIZE is the serializer's generic safety +// limit (32 MB), not a block rule. Bitcoin 0.1.0 predated the later 1 MB block +// cap, so this tree inherited no real block-size consensus limit. +static const unsigned int MAX_BLOCK_SIZE = 1000000; static const int64 COIN = 100000000; // Total Bitflash emission: identical to Bitcoin (21 million). // MAX_MONEY guards against the value overflow bug (CVE-2010-5139), which in @@ -1053,6 +1057,23 @@ public: return RandomXPoWHash((const void*)BEGIN(nVersion), END(nNonce) - BEGIN(nVersion)); } + bool CheckSizeLimits() const + { + // The middle test compares a transaction *count* against a *byte* + // limit. It is inherited from 0.1.0, where the same line compared + // vtx.size() against MAX_SIZE, and it is inert: the smallest possible + // transaction serializes to more than sixty bytes, so a block holding + // over a million of them cannot also weigh under a megabyte. + // + // Kept rather than removed. This is consensus code, and a rewrite that + // reads better is still a rewrite that can change what the network + // accepts. Written down so the next reader does not have to derive it, + // or "fix" it into something that does. + return (!vtx.empty() && + vtx.size() <= MAX_BLOCK_SIZE && + ::GetSerializeSize(*this, SER_DISK) <= MAX_BLOCK_SIZE); + } + uint256 BuildMerkleTree() const { -- cgit v1.2.3