Move nonce/pow to end of block header, change post-pow hash (#794)

* move nonce/pow to end of block header, update call to cuckoo-miner
* change header hash to be pow only
* fix genesis block miner and tests

chain/tests/mine_simple_chain.rs

@@ -421,6 +421,7 @@ fn prepare_block_nosum(
 	diff: u64,
 	txs: Vec<&Transaction>,
 ) -> Block {
+	let proof_size = global::proofsize();
 	let key_id = kc.derive_key_id(diff as u32).unwrap();
 
 	let mut b = match core::core::Block::new(prev, txs, kc, &key_id, Difficulty::from_num(diff)) {
@@ -429,5 +430,6 @@ fn prepare_block_nosum(
 	};
 	b.header.timestamp = prev.timestamp + time::Duration::seconds(60);
 	b.header.total_difficulty = prev.total_difficulty.clone() + Difficulty::from_num(diff);
+	b.header.pow = core::core::Proof::random(proof_size);
 	b
 }

core/src/core/block.rs

@@ -22,7 +22,7 @@ use core::{Committed, Input, KernelFeatures, Output, OutputFeatures, Proof, Proo
            ShortId, SwitchCommitHash, Transaction, TxKernel};
 use consensus;
 use consensus::{exceeds_weight, reward, VerifySortOrder, REWARD};
-use core::hash::{Hash, Hashed, ZERO_HASH};
+use core::hash::{Hash, HashWriter, Hashed, ZERO_HASH};
 use core::id::ShortIdentifiable;
 use core::target::Difficulty;
 use core::transaction;
@@ -105,22 +105,22 @@ pub struct BlockHeader {
 	pub previous: Hash,
 	/// Timestamp at which the block was built.
 	pub timestamp: time::Tm,
+	/// Total accumulated difficulty since genesis block
+	pub total_difficulty: Difficulty,
 	/// Merklish root of all the commitments in the TxHashSet
 	pub output_root: Hash,
 	/// Merklish root of all range proofs in the TxHashSet
 	pub range_proof_root: Hash,
 	/// Merklish root of all transaction kernels in the TxHashSet
 	pub kernel_root: Hash,
-	/// Nonce increment used to mine this block.
-	pub nonce: u64,
-	/// Proof of work data.
-	pub pow: Proof,
-	/// Total accumulated difficulty since genesis block
-	pub total_difficulty: Difficulty,
 	/// Total accumulated sum of kernel offsets since genesis block.
 	/// We can derive the kernel offset sum for *this* block from
 	/// the total kernel offset of the previous block header.
 	pub total_kernel_offset: BlindingFactor,
+	/// Nonce increment used to mine this block.
+	pub nonce: u64,
+	/// Proof of work data.
+	pub pow: Proof,
 }
 
 impl Default for BlockHeader {
@@ -135,9 +135,9 @@ impl Default for BlockHeader {
 			output_root: ZERO_HASH,
 			range_proof_root: ZERO_HASH,
 			kernel_root: ZERO_HASH,
+			total_kernel_offset: BlindingFactor::zero(),
 			nonce: 0,
 			pow: Proof::zero(proof_size),
-			total_kernel_offset: BlindingFactor::zero(),
 		}
 	}
 }
@@ -145,23 +145,11 @@ impl Default for BlockHeader {
 /// Serialization of a block header
 impl Writeable for BlockHeader {
 	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ser::Error> {
-		ser_multiwrite!(
-			writer,
-			[write_u16, self.version],
-			[write_u64, self.height],
-			[write_fixed_bytes, &self.previous],
-			[write_i64, self.timestamp.to_timespec().sec],
-			[write_fixed_bytes, &self.output_root],
-			[write_fixed_bytes, &self.range_proof_root],
-			[write_fixed_bytes, &self.kernel_root]
-		);
-
-		try!(writer.write_u64(self.nonce));
-		try!(self.total_difficulty.write(writer));
-		try!(self.total_kernel_offset.write(writer));
-
-		if writer.serialization_mode() != ser::SerializationMode::Hash {
+		if writer.serialization_mode() == ser::SerializationMode::Hash {
 			try!(self.pow.write(writer));
+		} else {
+			self.write_pre_pow(writer)?;
+			self.pow.write(writer)?;
 		}
 		Ok(())
 	}
@@ -173,12 +161,12 @@ impl Readable for BlockHeader {
 		let (version, height) = ser_multiread!(reader, read_u16, read_u64);
 		let previous = Hash::read(reader)?;
 		let timestamp = reader.read_i64()?;
+		let total_difficulty = Difficulty::read(reader)?;
 		let output_root = Hash::read(reader)?;
 		let rproof_root = Hash::read(reader)?;
 		let kernel_root = Hash::read(reader)?;
-		let nonce = reader.read_u64()?;
-		let total_difficulty = Difficulty::read(reader)?;
 		let total_kernel_offset = BlindingFactor::read(reader)?;
+		let nonce = reader.read_u64()?;
 		let pow = Proof::read(reader)?;
 
 		if timestamp > (1 << 60) {
@@ -193,17 +181,47 @@ impl Readable for BlockHeader {
 				sec: timestamp,
 				nsec: 0,
 			}),
+			total_difficulty: total_difficulty,
 			output_root: output_root,
 			range_proof_root: rproof_root,
 			kernel_root: kernel_root,
-			pow: pow,
-			nonce: nonce,
-			total_difficulty: total_difficulty,
 			total_kernel_offset: total_kernel_offset,
+			nonce: nonce,
+			pow: pow,
 		})
 	}
 }
 
+impl BlockHeader {
+	/// Write the pre-hash portion of the header
+	pub fn write_pre_pow<W: Writer>(&self, writer: &mut W) -> Result<(), ser::Error> {
+		ser_multiwrite!(
+			writer,
+			[write_u16, self.version],
+			[write_u64, self.height],
+			[write_fixed_bytes, &self.previous],
+			[write_i64, self.timestamp.to_timespec().sec],
+			[write_u64, self.total_difficulty.into_num()],
+			[write_fixed_bytes, &self.output_root],
+			[write_fixed_bytes, &self.range_proof_root],
+			[write_fixed_bytes, &self.kernel_root],
+			[write_fixed_bytes, &self.total_kernel_offset],
+			[write_u64, self.nonce]
+		);
+		Ok(())
+	}
+	///
+	/// Returns the pre-pow hash, as the post-pow hash
+	/// should just be the hash of the POW
+	pub fn pre_pow_hash(&self) -> Hash {
+		let mut hasher = HashWriter::default();
+		self.write_pre_pow(&mut hasher).unwrap();
+		let mut ret = [0; 32];
+		hasher.finalize(&mut ret);
+		Hash(ret)
+	}
+}
+
 /// Compact representation of a full block.
 /// Each input/output/kernel is represented as a short_id.
 /// A node is reasonably likely to have already seen all tx data (tx broadcast before block)
@@ -566,7 +584,7 @@ impl Block {
 		}.cut_through())
 	}
 
-	/// Blockhash, computed using only the header
+	/// Blockhash, computed using only the POW
 	pub fn hash(&self) -> Hash {
 		self.header.hash()
 	}
@@ -1124,7 +1142,7 @@ mod test {
 		let cb2 = b.as_compact_block();
 
 		// random nonce will not affect the hash of the compact block itself
-		// hash is based on header only
+		// hash is based on header POW only
 		assert!(cb1.nonce != cb2.nonce);
 		assert_eq!(b.hash(), cb1.hash());
 		assert_eq!(cb1.hash(), cb2.hash());

core/src/core/mod.rs

@@ -24,7 +24,8 @@ pub mod transaction;
 // pub mod txoset;
 #[allow(dead_code)]
 
-use std::fmt;
+use rand::{thread_rng, Rng};
+use std::{fmt, iter};
 use std::cmp::Ordering;
 use std::num::ParseFloatError;
 use consensus::GRIN_BASE;
@@ -152,6 +153,21 @@ impl Proof {
 		}
 	}
 
+	/// Builds a proof with random POW data,
+	/// needed so that tests that ignore POW
+	/// don't fail due to duplicate hashes
+	pub fn random(proof_size: usize) -> Proof {
+		let mut rng = thread_rng();
+		let v: Vec<u32> = iter::repeat(())
+			.map(|()| rng.gen())
+			.take(proof_size)
+			.collect();
+		Proof {
+			proof_size: proof_size,
+			nonces: v,
+		}
+	}
+
 	/// Converts the proof to a vector of u64s
 	pub fn to_u64s(&self) -> Vec<u64> {
 		let mut out_nonces = Vec::with_capacity(self.proof_size);

grin/src/miner.rs

@@ -51,64 +51,41 @@ use itertools::Itertools;
 // Max number of transactions this miner will assemble in a block
 const MAX_TX: u32 = 5000;
 
-const PRE_NONCE_SIZE: usize = 146;
-
-/// Serializer that outputs pre and post nonce portions of a block header
-/// which can then be sent off to miner to mutate at will
-pub struct HeaderPartWriter {
-	//
-	pub pre_nonce: Vec<u8>,
-	// Post nonce is currently variable length
-	// because of difficulty
-	pub post_nonce: Vec<u8>,
-	// which difficulty field we're on
-	bytes_written: usize,
-	writing_pre: bool,
+/// Serializer that outputs the pre-pow part of the header,
+/// including the nonce (last 8 bytes) that can be sent off
+/// to the miner to mutate at will
+pub struct HeaderPrePowWriter {
+	pub pre_pow: Vec<u8>,
 }
 
-impl Default for HeaderPartWriter {
-	fn default() -> HeaderPartWriter {
-		HeaderPartWriter {
-			bytes_written: 0,
-			writing_pre: true,
-			pre_nonce: Vec::new(),
-			post_nonce: Vec::new(),
+impl Default for HeaderPrePowWriter {
+	fn default() -> HeaderPrePowWriter {
+		HeaderPrePowWriter {
+			pre_pow: Vec::new(),
 		}
 	}
 }
 
-impl HeaderPartWriter {
-	pub fn parts_as_hex_strings(&self) -> (String, String) {
-		(
-			String::from(format!("{:02x}", self.pre_nonce.iter().format(""))),
-			String::from(format!("{:02x}", self.post_nonce.iter().format(""))),
-		)
+impl HeaderPrePowWriter {
+	pub fn as_hex_string(&self, include_nonce: bool) -> String {
+		let mut result = String::from(format!("{:02x}", self.pre_pow.iter().format("")));
+		if !include_nonce {
+			let l = result.len() - 16;
+			result.truncate(l);
+		}
+		result
 	}
 }
 
-impl ser::Writer for HeaderPartWriter {
+impl ser::Writer for HeaderPrePowWriter {
 	fn serialization_mode(&self) -> ser::SerializationMode {
-		ser::SerializationMode::Hash
+		ser::SerializationMode::Full
 	}
 
 	fn write_fixed_bytes<T: AsFixedBytes>(&mut self, bytes_in: &T) -> Result<(), ser::Error> {
-		if self.writing_pre {
 		for i in 0..bytes_in.len() {
-				self.pre_nonce.push(bytes_in.as_ref()[i])
+			self.pre_pow.push(bytes_in.as_ref()[i])
 		}
-		} else if self.bytes_written != 0 {
-			for i in 0..bytes_in.len() {
-				self.post_nonce.push(bytes_in.as_ref()[i])
-			}
-		}
-
-		self.bytes_written += bytes_in.len();
-
-		if self.bytes_written == PRE_NONCE_SIZE && self.writing_pre {
-			self.writing_pre = false;
-			self.bytes_written = 0;
-		}
-
 		Ok(())
 	}
 }
@@ -181,20 +158,13 @@ impl Miner {
 		let mut next_stat_output = time::get_time().sec + stat_output_interval;
 
 		// Get parts of the header
-		let mut header_parts = HeaderPartWriter::default();
-		ser::Writeable::write(&b.header, &mut header_parts).unwrap();
-		let (pre, post) = header_parts.parts_as_hex_strings();
-
-		//Just test output to mine a genesis block when needed
-		/*let mut header_parts = HeaderPartWriter::default();
-		let gen = genesis::genesis();
-		ser::Writeable::write(&gen.header, &mut header_parts).unwrap();
-		let (pre, post) = header_parts.parts_as_hex_strings();
-		println!("pre, post: {}, {}", pre, post);*/
+		let mut pre_pow_writer = HeaderPrePowWriter::default();
+		b.header.write_pre_pow(&mut pre_pow_writer).unwrap();
+		let pre_pow = pre_pow_writer.as_hex_string(false);
 
 		// Start the miner working
 		let miner = plugin_miner.get_consumable();
-		let job_handle = miner.notify(1, &pre, &post, 0).unwrap();
+		let job_handle = miner.notify(1, &pre_pow, "", 0).unwrap();
 
 		let mut sol = None;
 
@@ -320,7 +290,7 @@ impl Miner {
 
 		let mut sol = None;
 		while head.hash() == *latest_hash && time::get_time().sec < deadline {
-			let pow_hash = b.hash();
+			let pow_hash = b.header.pre_pow_hash();
 			if let Ok(proof) = plugin_miner.mine(&pow_hash[..]) {
 				let proof_diff = proof.clone().to_difficulty();
 				trace!(
@@ -437,7 +407,7 @@ impl Miner {
 
 		let mut sol = None;
 		while head.hash() == *latest_hash && time::get_time().sec < deadline {
-			let pow_hash = b.hash();
+			let pow_hash = b.header.pre_pow_hash();
 			if let Ok(proof) = miner.mine(&pow_hash[..]) {
 				let proof_diff = proof.clone().to_difficulty();
 				if proof_diff > (b.header.total_difficulty.clone() - head.total_difficulty.clone())
@@ -588,13 +558,13 @@ impl Miner {
 
 			// we found a solution, push our block through the chain processing pipeline
 			if let Some(proof) = sol {
+				b.header.pow = proof;
 				info!(
 					LOGGER,
 					"(Server ID: {}) Found valid proof of work, adding block {}.",
 					self.debug_output_id,
 					b.hash()
 				);
-				b.header.pow = proof;
 				let res = self.chain.process_block(b, chain::Options::MINE);
 				if let Err(e) = res {
 					error!(

pool/src/pool.rs

@@ -636,7 +636,7 @@ mod tests {
 	use std::sync::{Arc, RwLock};
 	use blake2;
 	use core::global::ChainTypes;
-	use core::core::SwitchCommitHash;
+	use core::core::{Proof, SwitchCommitHash};
 	use core::core::hash::{Hash, Hashed};
 	use core::core::pmmr::MerkleProof;
 	use core::core::target::Difficulty;
@@ -833,6 +833,7 @@ mod tests {
 	fn test_immature_coinbase() {
 		global::set_mining_mode(ChainTypes::AutomatedTesting);
 		let mut dummy_chain = DummyChainImpl::new();
+		let proof_size = global::proofsize();
 
 		let lock_height = 1 + global::coinbase_maturity();
 		assert_eq!(lock_height, 4);
@@ -848,12 +849,14 @@ mod tests {
 
 			let coinbase_header = block::BlockHeader {
 				height: 1,
+				pow: Proof::random(proof_size),
 				..block::BlockHeader::default()
 			};
 			chain_ref.store_head_header(&coinbase_header);
 
 			let head_header = block::BlockHeader {
 				height: 2,
+				pow: Proof::random(proof_size),
 				..block::BlockHeader::default()
 			};
 			chain_ref.store_head_header(&head_header);

pow/src/lib.rs

@@ -53,7 +53,6 @@ pub mod types;
 
 use core::consensus;
 use core::core::BlockHeader;
-use core::core::hash::Hashed;
 use core::core::Proof;
 use core::core::target::Difficulty;
 use core::global;
@@ -77,7 +76,8 @@ pub trait MiningWorker {
 /// Validates the proof of work of a given header, and that the proof of work
 /// satisfies the requirements of the header.
 pub fn verify_size(bh: &BlockHeader, cuckoo_sz: u32) -> bool {
-	Cuckoo::new(&bh.hash()[..], cuckoo_sz).verify(bh.pow.clone(), consensus::EASINESS as u64)
+	Cuckoo::new(&bh.pre_pow_hash()[..], cuckoo_sz)
+		.verify(bh.pow.clone(), consensus::EASINESS as u64)
 }
 
 /// Mines a genesis block, using the config specified miner if specified.
@@ -127,7 +127,7 @@ pub fn pow_size<T: MiningWorker + ?Sized>(
 	loop {
 		// can be trivially optimized by avoiding re-serialization every time but this
 		// is not meant as a fast miner implementation
-		let pow_hash = bh.hash();
+		let pow_hash = bh.pre_pow_hash();
 
 		// if we found a cycle (not guaranteed) and the proof hash is higher that the
 		// diff, we're all good