Make the maximum block size configurable (#7499)

* Make the maximum block size configurable

This pr makes the maximum block size configurable. The maximum block
size is used after proposing a new block to check if the new block is
not exceeding the maximum.

* Update primitives/consensus/common/src/evaluation.rs

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Added comment

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

substrate/primitives/consensus/common/src/evaluation.rs

@@ -17,8 +17,6 @@
 
 //! Block evaluation and evaluation errors.
 
-use super::MAX_BLOCK_SIZE;
-
 use codec::Encode;
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, One, CheckedConversion};
 
@@ -42,11 +40,8 @@ pub enum Error {
 	#[error("Proposal had wrong number. Expected {expected:?}, got {got:?}")]
 	WrongNumber { expected: BlockNumber, got: BlockNumber },
 	/// Proposal exceeded the maximum size.
-	#[error(
-		"Proposal exceeded the maximum size of {} by {} bytes.",
-		MAX_BLOCK_SIZE, .0.saturating_sub(MAX_BLOCK_SIZE)
-	)]
-	ProposalTooLarge(usize),
+	#[error("Proposal size {block_size} exceeds maximum allowed size of {max_block_size}.")]
+	ProposalTooLarge { block_size: usize, max_block_size: usize },
 }
 
 /// Attempt to evaluate a substrate block as a node block, returning error
@@ -55,28 +50,29 @@ pub fn evaluate_initial<Block: BlockT>(
 	proposal: &Block,
 	parent_hash: &<Block as BlockT>::Hash,
 	parent_number: <<Block as BlockT>::Header as HeaderT>::Number,
+	max_block_size: usize,
 ) -> Result<()> {
 
 	let encoded = Encode::encode(proposal);
 	let proposal = Block::decode(&mut &encoded[..])
 		.map_err(|e| Error::BadProposalFormat(e))?;
 
-	if encoded.len() > MAX_BLOCK_SIZE {
-		return Err(Error::ProposalTooLarge(encoded.len()))
+	if encoded.len() > max_block_size {
+		return Err(Error::ProposalTooLarge { max_block_size, block_size: encoded.len() })
 	}
 
 	if *parent_hash != *proposal.header().parent_hash() {
 		return Err(Error::WrongParentHash {
 			expected: format!("{:?}", *parent_hash),
 			got: format!("{:?}", proposal.header().parent_hash())
-		});
+		})
 	}
 
 	if parent_number + One::one() != *proposal.header().number() {
 		return Err(Error::WrongNumber {
 			expected: parent_number.checked_into::<u128>().map(|x| x + 1),
 			got: (*proposal.header().number()).checked_into::<u128>(),
-		});
+		})
 	}
 
 	Ok(())

substrate/primitives/consensus/common/src/lib.rs

@@ -46,9 +46,6 @@ pub mod import_queue;
 pub mod evaluation;
 mod metrics;
 
-// block size limit.
-const MAX_BLOCK_SIZE: usize = 4 * 1024 * 1024 + 512;
-
 pub use self::error::Error;
 pub use block_import::{
 	BlockImport, BlockOrigin, ForkChoiceStrategy, ImportedAux, BlockImportParams, BlockCheckParams,