Rust Cuckatoo for verifier and test-miner (#1558)

* cuck placeholder

* rustfmt

* cuckatoo, early days

* rustfmt

* data structures are in place, siphash key creation is consistent with @tromp

* solver in place, (not yet working)

* cuckatoo test solver working with test nonce

* rustfmt

* update solver to remove adjacency list removals

* verifier functioning

* rustfmt

* Proper error handing in Cuckatoo module, couple of tests

* modify cuckoo/cuckatoo solvers and verifiers to function identically, in advance of trait refactoring

* rustfmt

* refactor PoW context into trait, default to using cuckoo context

* rustfmt

* create macros for integer casting/unwraps

* don't instantiate structs when just verifying, add test validation vector for cuckatoo 29

* rustfmt

* don't init cuckoo structs if just validating

* test fix

* ensure BH hashing for POW is only done within miner/validators

Cargo.lock

@@ -740,6 +740,7 @@ dependencies = [
  "grin_wallet 0.3.0",
  "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lru-cache 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-bigint 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1411,6 +1412,7 @@ name = "num"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
+ "num-bigint 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-complex 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-iter 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1488,6 +1490,7 @@ name = "num-rational"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
+ "num-bigint 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

chain/src/chain.rs

@@ -28,7 +28,7 @@ use core::core::merkle_proof::MerkleProof;
 use core::core::verifier_cache::VerifierCache;
 use core::core::{Block, BlockHeader, BlockSums, Output, OutputIdentifier, Transaction, TxKernel};
 use core::global;
-use core::pow::Difficulty;
+use core::pow::{self, Difficulty};
 use error::{Error, ErrorKind};
 use grin_store::Error::NotFoundErr;
 use pipe;
@@ -153,7 +153,7 @@ pub struct Chain {
 	block_hashes_cache: Arc<RwLock<VecDeque<Hash>>>,
 	verifier_cache: Arc<RwLock<VerifierCache>>,
 	// POW verification function
-	pow_verifier: fn(&BlockHeader, u8) -> bool,
+	pow_verifier: fn(&BlockHeader, u8) -> Result<(), pow::Error>,
 	archive_mode: bool,
 }
 
@@ -169,7 +169,7 @@ impl Chain {
 		db_env: Arc<lmdb::Environment>,
 		adapter: Arc<ChainAdapter>,
 		genesis: Block,
-		pow_verifier: fn(&BlockHeader, u8) -> bool,
+		pow_verifier: fn(&BlockHeader, u8) -> Result<(), pow::Error>,
 		verifier_cache: Arc<RwLock<VerifierCache>>,
 		archive_mode: bool,
 	) -> Result<Chain, Error> {

chain/src/pipe.rs

@@ -27,7 +27,7 @@ use core::core::verifier_cache::VerifierCache;
 use core::core::Committed;
 use core::core::{Block, BlockHeader, BlockSums};
 use core::global;
-use core::pow::Difficulty;
+use core::pow::{self, Difficulty};
 use error::{Error, ErrorKind};
 use grin_store;
 use store;
@@ -49,7 +49,7 @@ pub struct BlockContext {
 	/// The sync head
 	pub sync_head: Tip,
 	/// The POW verification function
-	pub pow_verifier: fn(&BlockHeader, u8) -> bool,
+	pub pow_verifier: fn(&BlockHeader, u8) -> Result<(), pow::Error>,
 	/// MMR sum tree states
 	pub txhashset: Arc<RwLock<txhashset::TxHashSet>>,
 	/// Recently processed blocks to avoid double-processing
@@ -439,7 +439,7 @@ fn validate_header(
 		if shift != consensus::SECOND_POW_SIZESHIFT && header.pow.scaling_difficulty != 1 {
 			return Err(ErrorKind::InvalidScaling.into());
 		}
-		if !(ctx.pow_verifier)(header, shift) {
+		if !(ctx.pow_verifier)(header, shift).is_ok() {
 			error!(
 				LOGGER,
 				"pipe: validate_header bad cuckoo shift size {}", shift
@@ -527,7 +527,8 @@ fn validate_block(
 			&prev.total_kernel_offset,
 			&prev.total_kernel_sum,
 			verifier_cache,
-		).map_err(|e| ErrorKind::InvalidBlockProof(e))?;
+		)
+		.map_err(|e| ErrorKind::InvalidBlockProof(e))?;
 	Ok(())
 }
 
@@ -567,8 +568,7 @@ fn verify_block_sums(b: &Block, ext: &mut txhashset::Extension) -> Result<(), Er
 	let offset = b.header.total_kernel_offset();
 
 	// Verify the kernel sums for the block_sums with the new block applied.
-	let (utxo_sum, kernel_sum) =
+	let (utxo_sum, kernel_sum) = (block_sums, b as &Committed).verify_kernel_sums(overage, offset)?;
-		(block_sums, b as &Committed).verify_kernel_sums(overage, offset)?;
 
 	// Save the new block_sums for the new block to the db via the batch.
 	ext.batch.save_block_sums(

core/Cargo.toml

@@ -14,6 +14,7 @@ failure = "0.1"
 failure_derive = "0.1"
 lazy_static = "1"
 lru-cache = "0.1"
+num = "0.2"
 num-bigint = "0.2"
 rand = "0.5"
 serde = "1"

core/src/core/block.rs

@@ -25,7 +25,7 @@ use std::sync::{Arc, RwLock};
 use consensus::{self, reward, REWARD};
 use core::committed::{self, Committed};
 use core::compact_block::{CompactBlock, CompactBlockBody};
-use core::hash::{Hash, HashWriter, Hashed, ZERO_HASH};
+use core::hash::{Hash, Hashed, ZERO_HASH};
 use core::verifier_cache::VerifierCache;
 use core::{
 	transaction, Commitment, Input, KernelFeatures, Output, OutputFeatures, Transaction,
@@ -278,16 +278,19 @@ impl BlockHeader {
 		Ok(())
 	}
 
-	/// Returns the pre-pow hash, as the post-pow hash
+	/// Return the pre-pow, unhashed
-	/// should just be the hash of the POW
+	/// Let the cuck(at)oo miner/verifier handle the hashing
-	pub fn pre_pow_hash(&self) -> Hash {
+	/// for consistency with how this call is performed everywhere
-		let mut hasher = HashWriter::default();
+	/// else
-		self.write_pre_pow(&mut hasher).unwrap();
+	pub fn pre_pow(&self) -> Vec<u8> {
-		self.pow.write_pre_pow(self.version, &mut hasher).unwrap();
+		let mut header_buf = vec![];
-		hasher.write_u64(self.pow.nonce).unwrap();
+		{
-		let mut ret = [0; 32];
+			let mut writer = ser::BinWriter::new(&mut header_buf);
-		hasher.finalize(&mut ret);
+			self.write_pre_pow(&mut writer).unwrap();
-		Hash(ret)
+			self.pow.write_pre_pow(self.version, &mut writer).unwrap();
+			writer.write_u64(self.pow.nonce).unwrap();
+		}
+		header_buf
 	}
 
 	/// Total difficulty accumulated by the proof of work on this header

core/src/global.rs

@@ -22,7 +22,7 @@ use consensus::{
 	DIFFICULTY_ADJUST_WINDOW, INITIAL_DIFFICULTY, MEDIAN_TIME_WINDOW, PROOFSIZE,
 	REFERENCE_SIZESHIFT,
 };
-use pow::Difficulty;
+use pow::{self, CuckooContext, Difficulty, EdgeType, PoWContext};
 /// An enum collecting sets of parameters used throughout the
 /// code wherever mining is needed. This should allow for
 /// different sets of parameters for different purposes,
@@ -93,10 +93,23 @@ impl Default for ChainTypes {
 	}
 }
 
+/// PoW test mining and verifier context
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub enum PoWContextTypes {
+	/// Classic Cuckoo
+	Cuckoo,
+	/// Bleeding edge Cuckatoo
+	Cuckatoo,
+}
+
 lazy_static!{
 	/// The mining parameter mode
 	pub static ref CHAIN_TYPE: RwLock<ChainTypes> =
 			RwLock::new(ChainTypes::Mainnet);
+
+	/// PoW context type to instantiate
+	pub static ref POW_CONTEXT_TYPE: RwLock<PoWContextTypes> =
+			RwLock::new(PoWContextTypes::Cuckoo);
 }
 
 /// Set the mining mode
@@ -105,6 +118,25 @@ pub fn set_mining_mode(mode: ChainTypes) {
 	*param_ref = mode;
 }
 
+/// Return either a cuckoo context or a cuckatoo context
+/// Single change point
+pub fn create_pow_context<T>(
+	edge_bits: u8,
+	proof_size: usize,
+	easiness_pct: u32,
+	max_sols: u32,
+) -> Result<Box<impl PoWContext<T>>, pow::Error>
+where
+	T: EdgeType,
+{
+	// Perform whatever tests, configuration etc are needed to determine desired context + edge size
+	// + params
+	// Hardcode to regular cuckoo for now
+	CuckooContext::<T>::new(edge_bits, proof_size, easiness_pct, max_sols)
+	// Or switch to cuckatoo as follows:
+	// CuckatooContext::<T>::new(edge_bits, proof_size, easiness_pct, max_sols)
+}
+
 /// The minimum acceptable sizeshift
 pub fn min_sizeshift() -> u8 {
 	let param_ref = CHAIN_TYPE.read().unwrap();

core/src/pow/common.rs

@@ -0,0 +1,153 @@
+// Copyright 2018 The Grin Developers
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Common types and traits for cuckoo/cuckatoo family of solvers
+
+use blake2::blake2b::blake2b;
+use pow::error::{Error, ErrorKind};
+use pow::num::{PrimInt, ToPrimitive};
+use pow::siphash::siphash24;
+use std::hash::Hash;
+use std::io::Cursor;
+use std::ops::{BitOrAssign, Mul};
+use std::{fmt, mem};
+
+use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
+
+/// Operations needed for edge type (going to be u32 or u64)
+pub trait EdgeType: PrimInt + ToPrimitive + Mul + BitOrAssign + Hash {}
+impl EdgeType for u32 {}
+impl EdgeType for u64 {}
+
+/// An edge in the Cuckoo graph, simply references two u64 nodes.
+#[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+pub struct Edge<T>
+where
+	T: EdgeType,
+{
+	pub u: T,
+	pub v: T,
+}
+
+impl<T> fmt::Display for Edge<T>
+where
+	T: EdgeType,
+{
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		write!(
+			f,
+			"(u: {}, v: {})",
+			self.u.to_u64().unwrap_or(0),
+			self.v.to_u64().unwrap_or(0)
+		)
+	}
+}
+
+/// An element of an adjencency list
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Link<T>
+where
+	T: EdgeType,
+{
+	pub next: T,
+	pub to: T,
+}
+
+impl<T> fmt::Display for Link<T>
+where
+	T: EdgeType,
+{
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		write!(
+			f,
+			"(next: {}, to: {})",
+			self.next.to_u64().unwrap_or(0),
+			self.to.to_u64().unwrap_or(0)
+		)
+	}
+}
+
+pub fn set_header_nonce(header: Vec<u8>, nonce: Option<u32>) -> Result<[u64; 4], Error> {
+	let len = header.len();
+	let mut header = header.clone();
+	if let Some(n) = nonce {
+		header.truncate(len - mem::size_of::<u32>());
+		header.write_u32::<LittleEndian>(n)?;
+	}
+	create_siphash_keys(header)
+}
+
+pub fn create_siphash_keys(header: Vec<u8>) -> Result<[u64; 4], Error> {
+	let h = blake2b(32, &[], &header);
+	let hb = h.as_bytes();
+	let mut rdr = Cursor::new(hb);
+	Ok([
+		rdr.read_u64::<LittleEndian>()?,
+		rdr.read_u64::<LittleEndian>()?,
+		rdr.read_u64::<LittleEndian>()?,
+		rdr.read_u64::<LittleEndian>()?,
+	])
+}
+
+/// Return siphash masked for type
+pub fn sipnode<T>(
+	keys: &[u64; 4],
+	edge: T,
+	edge_mask: &T,
+	uorv: u64,
+	shift: bool,
+) -> Result<T, Error>
+where
+	T: EdgeType,
+{
+	let hash_u64 = siphash24(
+		keys,
+		2 * edge.to_u64().ok_or(ErrorKind::IntegerCast)? + uorv,
+	);
+	let mut masked = hash_u64 & edge_mask.to_u64().ok_or(ErrorKind::IntegerCast)?;
+	if shift {
+		masked = masked << 1;
+		masked |= uorv;
+	}
+	Ok(T::from(masked).ok_or(ErrorKind::IntegerCast)?)
+}
+
+/// Macros to clean up integer unwrapping
+#[macro_export]
+macro_rules! to_u64 {
+	($n:expr) => {
+		$n.to_u64().ok_or(ErrorKind::IntegerCast)?
+	};
+}
+
+#[macro_export]
+macro_rules! to_u32 {
+	($n:expr) => {
+		$n.to_u64().ok_or(ErrorKind::IntegerCast)? as u32
+	};
+}
+
+#[macro_export]
+macro_rules! to_usize {
+	($n:expr) => {
+		$n.to_u64().ok_or(ErrorKind::IntegerCast)? as usize
+	};
+}
+
+#[macro_export]
+macro_rules! to_edge {
+	($n:expr) => {
+		T::from($n).ok_or(ErrorKind::IntegerCast)?
+	};
+}

core/src/pow/cuckatoo.rs

@@ -0,0 +1,461 @@
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Implementation of Cuckatoo Cycle designed by John Tromp.
+use pow::num::ToPrimitive;
+use std::mem;
+
+use byteorder::{BigEndian, LittleEndian, WriteBytesExt};
+use croaring::Bitmap;
+
+use pow::common::{self, EdgeType, Link};
+use pow::error::{Error, ErrorKind};
+use pow::{PoWContext, Proof};
+use util;
+
+struct Graph<T>
+where
+	T: EdgeType,
+{
+	/// Maximum number of edges
+	max_edges: T,
+	/// Maximum nodes
+	max_nodes: u64,
+	/// Adjacency links
+	links: Vec<Link<T>>,
+	/// Index into links array
+	adj_list: Vec<T>,
+	///
+	visited: Bitmap,
+	/// Maximum solutions
+	max_sols: u32,
+	///
+	pub solutions: Vec<Proof>,
+	/// proof size
+	proof_size: usize,
+	/// define NIL type
+	nil: T,
+}
+
+impl<T> Graph<T>
+where
+	T: EdgeType,
+{
+	/// Create a new graph with given parameters
+	pub fn new(max_edges: T, max_sols: u32, proof_size: usize) -> Result<Graph<T>, Error> {
+		let max_nodes = 2 * to_u64!(max_edges);
+		Ok(Graph {
+			max_edges: max_edges,
+			max_nodes: max_nodes,
+			links: vec![],
+			adj_list: vec![],
+			visited: Bitmap::create(),
+			max_sols: max_sols,
+			solutions: vec![],
+			proof_size: proof_size,
+			nil: T::max_value(),
+		})
+	}
+
+	pub fn reset(&mut self) -> Result<(), Error> {
+		//TODO: Can be optimised
+		self.links = Vec::with_capacity(2 * self.max_nodes as usize);
+		self.adj_list = vec![T::max_value(); 2 * self.max_nodes as usize];
+		self.solutions = vec![Proof::zero(self.proof_size); 1];
+		self.visited = Bitmap::create();
+		Ok(())
+	}
+
+	pub fn byte_count(&self) -> Result<u64, Error> {
+		Ok(
+			2 * to_u64!(self.max_edges) * mem::size_of::<Link<T>>() as u64
+				+ mem::size_of::<T>() as u64 * 2 * self.max_nodes,
+		)
+	}
+
+	/// Add an edge to the graph
+	pub fn add_edge(&mut self, u: T, mut v: T) -> Result<(), Error> {
+		let max_nodes_t = to_edge!(self.max_nodes);
+		if u >= max_nodes_t || v >= max_nodes_t {
+			return Err(ErrorKind::EdgeAddition)?;
+		}
+		v = v + to_edge!(self.max_nodes);
+		let adj_u = self.adj_list[to_usize!(u ^ T::one())];
+		let adj_v = self.adj_list[to_usize!(v ^ T::one())];
+		if adj_u != self.nil && adj_v != self.nil {
+			let sol_index = self.solutions.len() - 1;
+			self.solutions[sol_index].nonces[0] = self.links.len() as u64 / 2;
+			self.cycles_with_link(1, u, v)?;
+		}
+		let ulink = self.links.len();
+		let vlink = self.links.len() + 1;
+		if to_edge!(vlink) == self.nil {
+			return Err(ErrorKind::EdgeAddition)?;
+		}
+		self.links.push(Link {
+			next: self.adj_list[to_usize!(u)],
+			to: u,
+		});
+		self.links.push(Link {
+			next: self.adj_list[to_usize!(v)],
+			to: v,
+		});
+		self.adj_list[to_usize!(u)] = T::from(ulink).ok_or(ErrorKind::IntegerCast)?;
+		self.adj_list[to_usize!(v)] = T::from(vlink).ok_or(ErrorKind::IntegerCast)?;
+		Ok(())
+	}
+
+	fn test_bit(&mut self, u: u64) -> bool {
+		self.visited.contains(u as u32)
+	}
+
+	fn cycles_with_link(&mut self, len: u32, u: T, dest: T) -> Result<(), Error> {
+		if self.test_bit(to_u64!(u >> 1)) {
+			return Ok(());
+		}
+		if (u ^ T::one()) == dest {
+			if len == self.proof_size as u32 {
+				if self.solutions.len() < self.max_sols as usize {
+					// create next solution
+					self.solutions.push(Proof::zero(self.proof_size));
+				}
+				return Ok(());
+			}
+		} else if len == self.proof_size as u32 {
+			return Ok(());
+		}
+		let mut au1 = self.adj_list[to_usize!(u ^ T::one())];
+		if au1 != self.nil {
+			self.visited.add(to_u32!(u >> 1));
+			while au1 != self.nil {
+				let i = self.solutions.len() - 1;
+				self.solutions[i].nonces[len as usize] = to_u64!(au1) / 2;
+				let link_index = to_usize!(au1 ^ T::one());
+				let link = self.links[link_index].to;
+				if link != self.nil {
+					self.cycles_with_link(len + 1, link, dest)?;
+				}
+				au1 = self.links[to_usize!(au1)].next;
+			}
+			self.visited.remove(to_u32!(u >> 1));
+		}
+		Ok(())
+	}
+}
+
+/// Cuckatoo solver context
+pub struct CuckatooContext<T>
+where
+	T: EdgeType,
+{
+	siphash_keys: [u64; 4],
+	easiness: T,
+	graph: Graph<T>,
+	proof_size: usize,
+	edge_mask: T,
+}
+
+impl<T> PoWContext<T> for CuckatooContext<T>
+where
+	T: EdgeType,
+{
+	fn new(
+		edge_bits: u8,
+		proof_size: usize,
+		easiness_pct: u32,
+		max_sols: u32,
+	) -> Result<Box<Self>, Error> {
+		Ok(Box::new(CuckatooContext::<T>::new_impl(
+			edge_bits,
+			proof_size,
+			easiness_pct,
+			max_sols,
+		)?))
+	}
+
+	fn set_header_nonce(
+		&mut self,
+		header: Vec<u8>,
+		nonce: Option<u32>,
+		solve: bool,
+	) -> Result<(), Error> {
+		self.set_header_nonce_impl(header, nonce, solve)
+	}
+
+	fn find_cycles(&mut self) -> Result<Vec<Proof>, Error> {
+		self.find_cycles_impl()
+	}
+
+	fn verify(&self, proof: &Proof) -> Result<(), Error> {
+		self.verify_impl(proof)
+	}
+}
+
+impl<T> CuckatooContext<T>
+where
+	T: EdgeType,
+{
+	/// New Solver context
+	pub fn new_impl(
+		edge_bits: u8,
+		proof_size: usize,
+		easiness_pct: u32,
+		max_sols: u32,
+	) -> Result<CuckatooContext<T>, Error> {
+		let num_edges = 1 << edge_bits;
+		let num_nodes = 2 * num_edges as u64;
+		let easiness = to_u64!(easiness_pct) * num_nodes / 100;
+		Ok(CuckatooContext {
+			siphash_keys: [0; 4],
+			easiness: to_edge!(easiness),
+			graph: Graph::new(to_edge!(num_edges), max_sols, proof_size)?,
+			proof_size: proof_size,
+			edge_mask: to_edge!(num_edges - 1),
+		})
+	}
+
+	/// Get a siphash key as a hex string (for display convenience)
+	pub fn sipkey_hex(&self, index: usize) -> Result<String, Error> {
+		let mut rdr = vec![];
+		rdr.write_u64::<BigEndian>(self.siphash_keys[index])?;
+		Ok(util::to_hex(rdr))
+	}
+
+	/// Return number of bytes used by the graph
+	pub fn byte_count(&self) -> Result<u64, Error> {
+		self.graph.byte_count()
+	}
+
+	/// Set the header and optional nonce in the last part of the header
+	pub fn set_header_nonce_impl(
+		&mut self,
+		mut header: Vec<u8>,
+		nonce: Option<u32>,
+		solve: bool,
+	) -> Result<(), Error> {
+		let len = header.len();
+		header.truncate(len - mem::size_of::<u32>());
+		if let Some(n) = nonce {
+			header.write_u32::<LittleEndian>(n)?;
+		}
+		self.siphash_keys = common::set_header_nonce(header, nonce)?;
+		if solve {
+			self.graph.reset()?;
+		}
+		Ok(())
+	}
+
+	/// Return siphash masked for type
+	fn sipnode(&self, edge: T, uorv: u64) -> Result<T, Error> {
+		common::sipnode::<T>(&self.siphash_keys, edge, &self.edge_mask, uorv, false)
+	}
+
+	/// Simple implementation of algorithm
+	pub fn find_cycles_impl(&mut self) -> Result<Vec<Proof>, Error> {
+		for n in 0..to_u64!(self.easiness) {
+			let u = self.sipnode(to_edge!(n), 0)?;
+			let v = self.sipnode(to_edge!(n), 1)?;
+			self.graph.add_edge(to_edge!(u), to_edge!(v))?;
+		}
+		self.graph.solutions.pop();
+		for s in &mut self.graph.solutions {
+			s.nonces.sort();
+		}
+		for s in &self.graph.solutions {
+			self.verify_impl(&s)?;
+		}
+		if self.graph.solutions.len() == 0 {
+			Err(ErrorKind::NoSolution)?
+		} else {
+			Ok(self.graph.solutions.clone())
+		}
+	}
+
+	/// Verify that given edges are ascending and form a cycle in a header-generated
+	/// graph
+	pub fn verify_impl(&self, proof: &Proof) -> Result<(), Error> {
+		let nonces = &proof.nonces;
+		let mut uvs = vec![0u64; 2 * proof.proof_size()];
+		let mut xor0: u64 = (self.proof_size as u64 / 2) & 1;
+		let mut xor1: u64 = xor0;
+
+		for n in 0..proof.proof_size() {
+			if nonces[n] > to_u64!(self.edge_mask) {
+				return Err(ErrorKind::Verification("edge too big".to_owned()))?;
+			}
+			if n > 0 && nonces[n] <= nonces[n - 1] {
+				return Err(ErrorKind::Verification("edges not ascending".to_owned()))?;
+			}
+			uvs[2 * n] = to_u64!(self.sipnode(to_edge!(nonces[n]), 0)?);
+			uvs[2 * n + 1] = to_u64!(self.sipnode(to_edge!(nonces[n]), 1)?);
+			xor0 ^= uvs[2 * n];
+			xor1 ^= uvs[2 * n + 1];
+		}
+		if xor0 | xor1 != 0 {
+			return Err(ErrorKind::Verification(
+				"endpoints don't match up".to_owned(),
+			))?;
+		}
+		let mut n = 0;
+		let mut i = 0;
+		let mut j;
+		loop {
+			// follow cycle
+			j = i;
+			let mut k = j;
+			loop {
+				k = (k + 2) % (2 * self.proof_size);
+				if k == i {
+					break;
+				}
+				if uvs[k] >> 1 == uvs[i] >> 1 {
+					// find other edge endpoint matching one at i
+					if j != i {
+						return Err(ErrorKind::Verification("branch in cycle".to_owned()))?;
+					}
+					j = k;
+				}
+			}
+			if j == i || uvs[j] == uvs[i] {
+				return Err(ErrorKind::Verification("cycle dead ends".to_owned()))?;
+			}
+			i = j ^ 1;
+			n += 1;
+			if i == 0 {
+				break;
+			}
+		}
+		if n == self.proof_size {
+			Ok(())
+		} else {
+			Err(ErrorKind::Verification("cycle too short".to_owned()))?
+		}
+	}
+}
+
+#[cfg(test)]
+mod test {
+	use super::*;
+
+	// Cuckatoo 29 Solution for Header [0u8;80] - nonce 20
+	static V1_29: [u64; 42] = [
+		0x48a9e2, 0x9cf043, 0x155ca30, 0x18f4783, 0x248f86c, 0x2629a64, 0x5bad752, 0x72e3569,
+		0x93db760, 0x97d3b37, 0x9e05670, 0xa315d5a, 0xa3571a1, 0xa48db46, 0xa7796b6, 0xac43611,
+		0xb64912f, 0xbb6c71e, 0xbcc8be1, 0xc38a43a, 0xd4faa99, 0xe018a66, 0xe37e49c, 0xfa975fa,
+		0x11786035, 0x1243b60a, 0x12892da0, 0x141b5453, 0x1483c3a0, 0x1505525e, 0x1607352c,
+		0x16181fe3, 0x17e3a1da, 0x180b651e, 0x1899d678, 0x1931b0bb, 0x19606448, 0x1b041655,
+		0x1b2c20ad, 0x1bd7a83c, 0x1c05d5b0, 0x1c0b9caa,
+	];
+
+	#[test]
+	fn cuckatoo() {
+		let ret = basic_solve::<u32>();
+		if let Err(r) = ret {
+			panic!("basic_solve u32: Error: {}", r);
+		}
+		let ret = basic_solve::<u64>();
+		if let Err(r) = ret {
+			panic!("basic_solve u64: Error: {}", r);
+		}
+		let ret = validate29_vectors::<u32>();
+		if let Err(r) = ret {
+			panic!("validate_29_vectors u32: Error: {}", r);
+		}
+		let ret = validate29_vectors::<u64>();
+		if let Err(r) = ret {
+			panic!("validate_29_vectors u64: Error: {}", r);
+		}
+		let ret = validate_fail::<u32>();
+		if let Err(r) = ret {
+			panic!("validate_fail u32: Error: {}", r);
+		}
+		let ret = validate_fail::<u64>();
+		if let Err(r) = ret {
+			panic!("validate_fail u64: Error: {}", r);
+		}
+	}
+
+	fn validate29_vectors<T>() -> Result<(), Error>
+	where
+		T: EdgeType,
+	{
+		let mut ctx = CuckatooContext::<T>::new(29, 42, 50, 10)?;
+		ctx.set_header_nonce([0u8; 80].to_vec(), Some(20), false)?;
+		assert!(ctx.verify(&Proof::new(V1_29.to_vec().clone())).is_ok());
+		Ok(())
+	}
+
+	fn validate_fail<T>() -> Result<(), Error>
+	where
+		T: EdgeType,
+	{
+		let mut ctx = CuckatooContext::<T>::new(29, 42, 50, 10)?;
+		let mut header = [0u8; 80];
+		header[0] = 1u8;
+		ctx.set_header_nonce(header.to_vec(), Some(20), false)?;
+		assert!(!ctx.verify(&Proof::new(V1_29.to_vec().clone())).is_ok());
+		header[0] = 0u8;
+		ctx.set_header_nonce(header.to_vec(), Some(20), false)?;
+		assert!(ctx.verify(&Proof::new(V1_29.to_vec().clone())).is_ok());
+		let mut bad_proof = V1_29.clone();
+		bad_proof[0] = 0x48a9e1;
+		assert!(!ctx.verify(&Proof::new(bad_proof.to_vec())).is_ok());
+		Ok(())
+	}
+
+	fn basic_solve<T>() -> Result<(), Error>
+	where
+		T: EdgeType,
+	{
+		let easiness_pct = 50;
+		let nonce = 1546569;
+		let _range = 1;
+		let header = [0u8; 80].to_vec();
+		let proof_size = 42;
+		let edge_bits = 15;
+		let max_sols = 4;
+
+		println!(
+			"Looking for {}-cycle on cuckatoo{}(\"{}\",{}) with {}% edges",
+			proof_size,
+			edge_bits,
+			String::from_utf8(header.clone()).unwrap(),
+			nonce,
+			easiness_pct
+		);
+		let mut ctx_u32 = CuckatooContext::<T>::new(edge_bits, proof_size, easiness_pct, max_sols)?;
+		let mut bytes = ctx_u32.byte_count()?;
+		let mut unit = 0;
+		while bytes >= 10240 {
+			bytes >>= 10;
+			unit += 1;
+		}
+		println!("Using {}{}B memory", bytes, [' ', 'K', 'M', 'G', 'T'][unit]);
+		ctx_u32.set_header_nonce(header, Some(nonce), true)?;
+		println!(
+			"Nonce {} k0 k1 k2 k3 {} {} {} {}",
+			nonce,
+			ctx_u32.sipkey_hex(0)?,
+			ctx_u32.sipkey_hex(1)?,
+			ctx_u32.sipkey_hex(2)?,
+			ctx_u32.sipkey_hex(3)?
+		);
+		let sols = ctx_u32.find_cycles()?;
+		// We know this nonce has 2 solutions
+		assert_eq!(sols.len(), 2);
+		for s in sols {
+			println!("{:?}", s);
+		}
+		Ok(())
+	}
+}

core/src/pow/cuckoo.rs

@@ -17,233 +17,174 @@
 //! simple miner is included, mostly for testing purposes. John Tromp's Tomato
 //! miner will be much faster in almost every environment.
 
+use pow::common::{self, Edge, EdgeType};
+use pow::error::{Error, ErrorKind};
+use pow::num::ToPrimitive;
+use pow::{PoWContext, Proof};
+
 use std::cmp;
 use std::collections::HashSet;
 
-use core::BlockHeader;
-use pow::siphash::siphash24;
-use pow::Proof;
-
 const MAXPATHLEN: usize = 8192;
 
-/// A cuckoo-cycle related error
-#[derive(Debug)]
-pub enum Error {
-	/// Unable to find a short enough path
-	Path,
-	/// Unable to find a solution
-	NoSolution,
-}
-
-/// An edge in the Cuckoo graph, simply references two u64 nodes.
-#[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
-struct Edge {
-	u: u64,
-	v: u64,
-}
-
 /// Cuckoo cycle context
-pub struct Cuckoo {
+pub struct CuckooContext<T>
-	mask: u64,
+where
-	size: u64,
+	T: EdgeType,
-	v: [u64; 4],
+{
+	edge_bits: u8,
+	siphash_keys: [u64; 4],
+	easiness: T,
+	proof_size: usize,
+	edge_mask: T,
+	graph: Vec<T>,
+	_max_sols: u32,
 }
 
-impl Cuckoo {
+impl<T> PoWContext<T> for CuckooContext<T>
-	/// Initializes a new Cuckoo Cycle setup, using the provided byte array to
+where
-	/// generate a seed. In practice for PoW applications the byte array is a
+	T: EdgeType,
-	/// serialized block header.
+{
-	pub fn from_hash(header_hash: &[u8], sizeshift: u8) -> Cuckoo {
+	fn new(
-		let size = 1 << sizeshift;
+		edge_bits: u8,
-		Cuckoo {
+		proof_size: usize,
-			v: [
+		easiness_pct: u32,
-				u8_to_u64(header_hash, 0),
+		max_sols: u32,
-				u8_to_u64(header_hash, 8),
+	) -> Result<Box<Self>, Error> {
-				u8_to_u64(header_hash, 16),
+		Ok(Box::new(CuckooContext::<T>::new_impl(
-				u8_to_u64(header_hash, 24),
+			edge_bits,
-			],
+			proof_size,
-			size: size,
+			easiness_pct,
-			mask: (1 << sizeshift) / 2 - 1,
+			max_sols,
+		)?))
 	}
+
+	fn set_header_nonce(
+		&mut self,
+		header: Vec<u8>,
+		nonce: Option<u32>,
+		solve: bool,
+	) -> Result<(), Error> {
+		self.set_header_nonce_impl(header, nonce, solve)
+	}
+
+	fn find_cycles(&mut self) -> Result<Vec<Proof>, Error> {
+		self.find_cycles_impl()
+	}
+
+	fn verify(&self, proof: &Proof) -> Result<(), Error> {
+		self.verify_impl(proof)
+	}
+}
+
+impl<T> CuckooContext<T>
+where
+	T: EdgeType,
+{
+	/// Create a new cuckoo context with given parameters
+	pub fn new_impl(
+		edge_bits: u8,
+		proof_size: usize,
+		easiness_pct: u32,
+		max_sols: u32,
+	) -> Result<CuckooContext<T>, Error> {
+		let num_edges = 1 << edge_bits;
+		let easiness = to_u64!(easiness_pct) * num_edges / 100;
+		Ok(CuckooContext {
+			edge_bits: edge_bits,
+			siphash_keys: [0; 4],
+			easiness: to_edge!(easiness),
+			proof_size: proof_size,
+			edge_mask: to_edge!(num_edges / 2 - 1),
+			graph: vec![T::zero(); num_edges as usize + 1],
+			_max_sols: max_sols,
+		})
+	}
+
+	fn reset(&mut self) -> Result<(), Error> {
+		let num_edges = 1 << self.edge_bits;
+		self.graph = vec![T::zero(); num_edges + 1];
+		Ok(())
+	}
+
+	/// Set the header and optional nonce in the last part of the header
+	/// and create siphash keys
+	pub fn set_header_nonce_impl(
+		&mut self,
+		header: Vec<u8>,
+		nonce: Option<u32>,
+		solve: bool,
+	) -> Result<(), Error> {
+		self.siphash_keys = common::set_header_nonce(header, nonce)?;
+		if solve {
+			self.reset()?;
+		}
+		Ok(())
 	}
 
 	/// Generates a node in the cuckoo graph generated from our seed. A node is
 	/// simply materialized as a u64 from a nonce and an offset (generally 0 or
 	/// 1).
-	fn new_node(&self, nonce: u64, uorv: u64) -> u64 {
+	fn new_node(&self, edge: T, uorv: u64) -> Result<T, Error> {
-		return ((siphash24(self.v, 2 * nonce + uorv) & self.mask) << 1) | uorv;
+		common::sipnode::<T>(&self.siphash_keys, edge, &self.edge_mask, uorv, true)
 	}
 
 	/// Creates a new edge in the cuckoo graph generated by our seed from a
 	/// nonce. Generates two node coordinates from the nonce and links them
 	/// together.
-	fn new_edge(&self, nonce: u64) -> Edge {
+	fn new_edge(&self, nonce: T) -> Result<Edge<T>, Error> {
-		Edge {
+		Ok(Edge {
-			u: self.new_node(nonce, 0),
+			u: self.new_node(nonce, 0)?,
-			v: self.new_node(nonce, 1),
+			v: self.new_node(nonce, 1)?,
-		}
+		})
 	}
 
-	/// Assuming increasing nonces all smaller than easiness, verifies the
+	fn path(&self, mut u: T, us: &mut [T]) -> Result<T, Error> {
-	/// nonces form a cycle in a Cuckoo graph. Each nonce generates an edge, we
-	/// build the nodes on both side of that edge and count the connections.
-	pub fn verify(&self, proof: &Proof, ease: u64) -> bool {
-		let easiness = ease * (self.size as u64) / 100;
-		let nonces = &proof.nonces;
-		let mut us = vec![0; proof.proof_size()];
-		let mut vs = vec![0; proof.proof_size()];
-		for n in 0..proof.proof_size() {
-			if nonces[n] >= easiness || (n != 0 && nonces[n] <= nonces[n - 1]) {
-				return false;
-			}
-			us[n] = self.new_node(nonces[n], 0);
-			vs[n] = self.new_node(nonces[n], 1);
-		}
-		let mut i = 0;
-		let mut count = proof.proof_size();
-		loop {
-			let mut j = i;
-			for k in 0..proof.proof_size() {
-				// find unique other j with same vs[j]
-				if k != i && vs[k] == vs[i] {
-					if j != i {
-						return false;
-					}
-					j = k;
-				}
-			}
-			if j == i {
-				return false;
-			}
-			i = j;
-			for k in 0..proof.proof_size() {
-				// find unique other i with same us[i]
-				if k != j && us[k] == us[j] {
-					if i != j {
-						return false;
-					}
-					i = k;
-				}
-			}
-			if i == j {
-				return false;
-			}
-			count -= 2;
-			if i == 0 {
-				break;
-			}
-		}
-		count == 0
-	}
-}
-
-/// Miner for the Cuckoo Cycle algorithm. While the verifier will work for
-/// graph sizes up to a u64, the miner is limited to u32 to be more memory
-/// compact (so shift <= 32). Non-optimized for now and and so mostly used for
-/// tests, being impractical with sizes greater than 2^22.
-pub struct Miner {
-	easiness: u64,
-	proof_size: usize,
-	cuckoo: Cuckoo,
-	graph: Vec<u32>,
-	sizeshift: u8,
-}
-
-/// What type of cycle we have found?
-enum CycleSol {
-	/// A cycle of the right length is a valid proof.
-	ValidProof(Vec<u32>),
-	/// A cycle of the wrong length is great, but not a proof.
-	InvalidCycle(usize),
-	/// No cycles have been found.
-	NoCycle,
-}
-
-impl Miner {
-	/// Creates a new miner for the provided block header
-	pub fn new(header: &BlockHeader, ease: u32, proof_size: usize, sizeshift: u8) -> Miner {
-		Miner::from_hash(header.pre_pow_hash().as_ref(), ease, proof_size, sizeshift)
-	}
-
-	/// Creates a new miner directly from a hash
-	pub fn from_hash(header_hash: &[u8], ease: u32, proof_size: usize, sizeshift: u8) -> Miner {
-		let cuckoo = Cuckoo::from_hash(header_hash, sizeshift);
-		let size = 1 << sizeshift;
-		let graph = vec![0; size + 1];
-		let easiness = (ease as u64) * (size as u64) / 100;
-		Miner {
-			easiness,
-			cuckoo,
-			graph,
-			proof_size,
-			sizeshift,
-		}
-	}
-
-	/// Searches for a solution
-	pub fn mine(&mut self) -> Result<Proof, Error> {
-		let mut us = [0; MAXPATHLEN];
-		let mut vs = [0; MAXPATHLEN];
-		for nonce in 0..self.easiness {
-			us[0] = self.cuckoo.new_node(nonce, 0) as u32;
-			vs[0] = self.cuckoo.new_node(nonce, 1) as u32;
-			let u = self.graph[us[0] as usize];
-			let v = self.graph[vs[0] as usize];
-			if us[0] == 0 {
-				continue; // ignore duplicate edges
-			}
-			let nu = self.path(u, &mut us)? as usize;
-			let nv = self.path(v, &mut vs)? as usize;
-
-			let sol = self.find_sol(nu, &us, nv, &vs);
-			match sol {
-				CycleSol::ValidProof(res) => {
-					let mut proof = Proof::new(map_vec!(res.to_vec(), |&n| n as u64));
-					proof.cuckoo_sizeshift = self.sizeshift;
-					return Ok(proof);
-				}
-				CycleSol::InvalidCycle(_) => continue,
-				CycleSol::NoCycle => {
-					self.update_graph(nu, &us, nv, &vs);
-				}
-			}
-		}
-		Err(Error::NoSolution)
-	}
-
-	fn path(&self, mut u: u32, us: &mut [u32]) -> Result<u32, Error> {
 		let mut nu = 0;
-		while u != 0 {
+		while u != T::zero() {
 			nu += 1;
 			if nu >= MAXPATHLEN {
 				while nu != 0 && us[(nu - 1) as usize] != u {
 					nu -= 1;
 				}
-				return Err(Error::Path);
+				return Err(ErrorKind::Path)?;
 			}
 			us[nu as usize] = u;
-			u = self.graph[u as usize];
+			u = self.graph[to_usize!(u)];
 		}
-		Ok(nu as u32)
+		Ok(to_edge!(nu))
 	}
 
-	fn update_graph(&mut self, mut nu: usize, us: &[u32], mut nv: usize, vs: &[u32]) {
+	fn update_graph(
+		&mut self,
+		mut nu: usize,
+		us: &[T],
+		mut nv: usize,
+		vs: &[T],
+	) -> Result<(), Error> {
 		if nu < nv {
 			while nu != 0 {
 				nu -= 1;
-				self.graph[us[nu + 1] as usize] = us[nu];
+				self.graph[to_usize!(us[nu + 1])] = us[nu];
 			}
-			self.graph[us[0] as usize] = vs[0];
+			self.graph[to_usize!(us[0])] = vs[0];
 		} else {
 			while nv != 0 {
 				nv -= 1;
-				self.graph[vs[nv + 1] as usize] = vs[nv];
+				self.graph[to_usize!(vs[nv + 1])] = vs[nv];
 			}
-			self.graph[vs[0] as usize] = us[0];
+			self.graph[to_usize!(vs[0])] = us[0];
 		}
+		Ok(())
 	}
 
-	fn find_sol(&mut self, mut nu: usize, us: &[u32], mut nv: usize, vs: &[u32]) -> CycleSol {
+	fn find_sol(
+		&mut self,
+		mut nu: usize,
+		us: &[T],
+		mut nv: usize,
+		vs: &[T],
+	) -> Result<Vec<T>, Error> {
 		if us[nu] == vs[nv] {
 			let min = cmp::min(nu, nv);
 			nu -= min;
@@ -253,71 +194,142 @@ impl Miner {
 				nv += 1;
 			}
 			if nu + nv + 1 == self.proof_size {
-				self.solution(&us, nu as u32, &vs, nv as u32)
+				self.solution(&us, nu as u64, &vs, nv as u64)
 			} else {
-				CycleSol::InvalidCycle(nu + nv + 1)
+				Err(ErrorKind::InvalidCycle(nu + nv + 1))?
 			}
 		} else {
-			CycleSol::NoCycle
+			Err(ErrorKind::NoCycle)?
 		}
 	}
 
-	fn solution(&mut self, us: &[u32], mut nu: u32, vs: &[u32], mut nv: u32) -> CycleSol {
+	fn solution(&mut self, us: &[T], mut nu: u64, vs: &[T], mut nv: u64) -> Result<Vec<T>, Error> {
 		let mut cycle = HashSet::new();
-		cycle.insert(Edge {
+		cycle.insert(Edge { u: us[0], v: vs[0] });
-			u: us[0] as u64,
-			v: vs[0] as u64,
-		});
 		while nu != 0 {
 			// u's in even position; v's in odd
-			nu -= 1;
+			nu = nu - 1;
 			cycle.insert(Edge {
-				u: us[((nu + 1) & !1) as usize] as u64,
+				u: us[((nu + 1) & !1) as usize],
-				v: us[(nu | 1) as usize] as u64,
+				v: us[(nu | 1) as usize],
 			});
 		}
 		while nv != 0 {
 			// u's in odd position; v's in even
 			nv -= 1;
 			cycle.insert(Edge {
-				u: vs[(nv | 1) as usize] as u64,
+				u: vs[(nv | 1) as usize],
-				v: vs[((nv + 1) & !1) as usize] as u64,
+				v: vs[((nv + 1) & !1) as usize],
 			});
 		}
 		let mut n = 0;
-		let mut sol = vec![0; self.proof_size];
+		let mut sol = vec![T::zero(); self.proof_size];
-		for nonce in 0..self.easiness {
+		for nonce in 0..to_usize!(self.easiness) {
-			let edge = self.cuckoo.new_edge(nonce);
+			let edge = self.new_edge(to_edge!(nonce))?;
 			if cycle.contains(&edge) {
-				sol[n] = nonce as u32;
+				sol[n] = to_edge!(nonce);
 				n += 1;
 				cycle.remove(&edge);
 			}
 		}
 		return if n == self.proof_size {
-			CycleSol::ValidProof(sol)
+			Ok(sol)
 		} else {
-			CycleSol::NoCycle
+			Err(ErrorKind::NoCycle)?
 		};
 	}
+
+	/// Searches for a solution (simple implementation)
+	pub fn find_cycles_impl(&mut self) -> Result<Vec<Proof>, Error> {
+		let mut us = [T::zero(); MAXPATHLEN];
+		let mut vs = [T::zero(); MAXPATHLEN];
+		for nonce in 0..to_usize!(self.easiness) {
+			us[0] = self.new_node(to_edge!(nonce), 0)?;
+			vs[0] = self.new_node(to_edge!(nonce), 1)?;
+			let u = self.graph[to_usize!(us[0])];
+			let v = self.graph[to_usize!(vs[0])];
+			if us[0] == T::zero() {
+				continue; // ignore duplicate edges
+			}
+			let nu = to_usize!(self.path(u, &mut us)?);
+			let nv = to_usize!(self.path(v, &mut vs)?);
+
+			let sol = self.find_sol(nu, &us, nv, &vs);
+			match sol {
+				Ok(s) => {
+					let mut proof = Proof::new(map_vec!(s.to_vec(), |&n| n.to_u64().unwrap_or(0)));
+					proof.cuckoo_sizeshift = self.edge_bits;
+					return Ok(vec![proof]);
+				}
+				Err(e) => match e.kind() {
+					ErrorKind::InvalidCycle(_) => continue,
+					ErrorKind::NoCycle => self.update_graph(nu, &us, nv, &vs)?,
+					_ => return Err(e),
+				},
+			}
+		}
+		Err(ErrorKind::NoSolution)?
 	}
 
-/// Utility to transform a 8 bytes of a byte array into a u64.
+	/// Assuming increasing nonces all smaller than easiness, verifies the
-fn u8_to_u64(p: &[u8], i: usize) -> u64 {
+	/// nonces form a cycle in a Cuckoo graph. Each nonce generates an edge, we
-	(p[i] as u64)
+	/// build the nodes on both side of that edge and count the connections.
-		| (p[i + 1] as u64) << 8
+	pub fn verify_impl(&self, proof: &Proof) -> Result<(), Error> {
-		| (p[i + 2] as u64) << 16
+		let easiness = to_u64!(self.easiness);
-		| (p[i + 3] as u64) << 24
+		let nonces = &proof.nonces;
-		| (p[i + 4] as u64) << 32
+		let mut us = vec![T::zero(); proof.proof_size()];
-		| (p[i + 5] as u64) << 40
+		let mut vs = vec![T::zero(); proof.proof_size()];
-		| (p[i + 6] as u64) << 48
+		for n in 0..proof.proof_size() {
-		| (p[i + 7] as u64) << 56
+			if nonces[n] >= easiness || (n != 0 && nonces[n] <= nonces[n - 1]) {
+				return Err(ErrorKind::Verification("edge wrong size".to_owned()))?;
+			}
+			us[n] = self.new_node(to_edge!(nonces[n]), 0)?;
+			vs[n] = self.new_node(to_edge!(nonces[n]), 1)?;
+		}
+		let mut i = 0;
+		let mut count = proof.proof_size();
+		loop {
+			let mut j = i;
+			for k in 0..proof.proof_size() {
+				// find unique other j with same vs[j]
+				if k != i && vs[k] == vs[i] {
+					if j != i {
+						return Err(ErrorKind::Verification("".to_owned()))?;
+					}
+					j = k;
+				}
+			}
+			if j == i {
+				return Err(ErrorKind::Verification("".to_owned()))?;
+			}
+			i = j;
+			for k in 0..proof.proof_size() {
+				// find unique other i with same us[i]
+				if k != j && us[k] == us[j] {
+					if i != j {
+						return Err(ErrorKind::Verification("".to_owned()))?;
+					}
+					i = k;
+				}
+			}
+			if i == j {
+				return Err(ErrorKind::Verification("".to_owned()))?;
+			}
+			count -= 2;
+			if i == 0 {
+				break;
+			}
+		}
+		match count == 0 {
+			true => Ok(()),
+			false => Err(ErrorKind::Verification("Invalid solution".to_owned()))?,
+		}
+	}
 }
 
 #[cfg(test)]
 mod test {
 	use super::*;
-	use blake2;
 
 	static V1: [u64; 42] = [
 		0x3bbd, 0x4e96, 0x1013b, 0x1172b, 0x1371b, 0x13e6a, 0x1aaa6, 0x1b575, 0x1e237, 0x1ee88,
@@ -350,99 +362,119 @@ mod test {
 		0x701f37b,
 	];
 
-	fn blake2(data: &[u8]) -> blake2::blake2b::Blake2bResult {
+	#[test]
-		blake2::blake2b::blake2b(32, &[], data)
+	fn cuckoo_context() {
+		let ret = mine20_vectors::<u32>();
+		if let Err(r) = ret {
+			panic!("mine20_vectors u32: Error: {}", r);
+		}
+		let ret = mine20_vectors::<u64>();
+		if let Err(r) = ret {
+			panic!("mine20_vectors u64: Error: {}", r);
+		}
+		let ret = validate20_vectors::<u32>();
+		if let Err(r) = ret {
+			panic!("validate20_vectors u32: Error: {}", r);
+		}
+		let ret = validate20_vectors::<u64>();
+		if let Err(r) = ret {
+			panic!("validate20_vectors u64: Error: {}", r);
+		}
+		let ret = validate_fail::<u32>();
+		if let Err(r) = ret {
+			panic!("validate_fail u32: Error: {}", r);
+		}
+		let ret = validate_fail::<u64>();
+		if let Err(r) = ret {
+			panic!("validate_fail u64: Error: {}", r);
+		}
+		let ret = mine16_validate::<u32>();
+		if let Err(r) = ret {
+			panic!("mine16_validate u32: Error: {}", r);
+		}
+		let ret = mine16_validate::<u64>();
+		if let Err(r) = ret {
+			panic!("mine16_validate u64: Error: {}", r);
+		}
 	}
 
 	/// Find a 42-cycle on Cuckoo20 at 75% easiness and verify against a few
 	/// known cycle proofs
 	/// generated by other implementations.
-	#[test]
+	fn mine20_vectors<T>() -> Result<(), Error>
-	fn mine20_vectors() {
+	where
-		let nonces1 = Miner::from_hash(blake2(&[49]).as_bytes(), 75, 42, 20)
+		T: EdgeType,
-			.mine()
+	{
-			.unwrap();
+		let mut cuckoo_ctx = CuckooContext::<T>::new(20, 42, 75, 10)?;
+		cuckoo_ctx.set_header_nonce([49].to_vec(), None, true)?;
+		let res = cuckoo_ctx.find_cycles()?;
 		let mut proof = Proof::new(V1.to_vec());
 		proof.cuckoo_sizeshift = 20;
-		assert_eq!(proof, nonces1);
+		assert_eq!(proof, res[0]);
 
-		let nonces2 = Miner::from_hash(blake2(&[50]).as_bytes(), 70, 42, 20)
+		let mut cuckoo_ctx = CuckooContext::<T>::new(20, 42, 70, 10)?;
-			.mine()
+		cuckoo_ctx.set_header_nonce([50].to_vec(), None, true)?;
-			.unwrap();
+		let res = cuckoo_ctx.find_cycles()?;
 		let mut proof = Proof::new(V2.to_vec());
 		proof.cuckoo_sizeshift = 20;
-		assert_eq!(proof, nonces2);
+		assert_eq!(proof, res[0]);
 
-		let nonces3 = Miner::from_hash(blake2(&[51]).as_bytes(), 70, 42, 20)
+		//re-use context
-			.mine()
+		cuckoo_ctx.set_header_nonce([51].to_vec(), None, true)?;
-			.unwrap();
+		let res = cuckoo_ctx.find_cycles()?;
 		let mut proof = Proof::new(V3.to_vec());
 		proof.cuckoo_sizeshift = 20;
-		assert_eq!(proof, nonces3);
+		assert_eq!(proof, res[0]);
+		Ok(())
 	}
 
-	#[test]
+	fn validate20_vectors<T>() -> Result<(), Error>
-	fn validate20_vectors() {
+	where
-		assert!(
+		T: EdgeType,
-			Cuckoo::from_hash(blake2(&[49]).as_bytes(), 20)
+	{
-				.verify(&Proof::new(V1.to_vec().clone()), 75)
+		let mut cuckoo_ctx = CuckooContext::<T>::new(20, 42, 75, 10)?;
-		);
+		cuckoo_ctx.set_header_nonce([49].to_vec(), None, false)?;
-		assert!(
+		assert!(cuckoo_ctx.verify(&Proof::new(V1.to_vec().clone())).is_ok());
-			Cuckoo::from_hash(blake2(&[50]).as_bytes(), 20)
+		let mut cuckoo_ctx = CuckooContext::<T>::new(20, 42, 70, 10)?;
-				.verify(&Proof::new(V2.to_vec().clone()), 70)
+		cuckoo_ctx.set_header_nonce([50].to_vec(), None, false)?;
-		);
+		assert!(cuckoo_ctx.verify(&Proof::new(V2.to_vec().clone())).is_ok());
-		assert!(
+		cuckoo_ctx.set_header_nonce([51].to_vec(), None, false)?;
-			Cuckoo::from_hash(blake2(&[51]).as_bytes(), 20)
+		assert!(cuckoo_ctx.verify(&Proof::new(V3.to_vec().clone())).is_ok());
-				.verify(&Proof::new(V3.to_vec().clone()), 70)
+		Ok(())
-		);
 	}
 
-	/// Just going to disable this for now, as it's painful to try and get a
+	fn validate_fail<T>() -> Result<(), Error>
-	/// valid cuckoo28 vector (TBD: 30 is more relevant now anyhow)
+	where
-	#[test]
+		T: EdgeType,
-	#[ignore]
+	{
-	fn validate28_vectors() {
-		let mut test_header = [0; 32];
-		test_header[0] = 24;
-		assert!(Cuckoo::from_hash(&test_header, 28).verify(&Proof::new(V4.to_vec().clone()), 50));
-	}
-
-	#[test]
-	fn validate_fail() {
 		// edge checks
-		assert!(
+		let mut cuckoo_ctx = CuckooContext::<T>::new(20, 42, 75, 10)?;
-			!Cuckoo::from_hash(blake2(&[49]).as_bytes(), 20).verify(&Proof::new(vec![0; 42]), 75)
+		cuckoo_ctx.set_header_nonce([49].to_vec(), None, false)?;
-		);
+		// edge checks
-		assert!(
+		assert!(!cuckoo_ctx.verify(&Proof::new(vec![0; 42])).is_ok());
-			!Cuckoo::from_hash(blake2(&[49]).as_bytes(), 20)
+		assert!(!cuckoo_ctx.verify(&Proof::new(vec![0xffff; 42])).is_ok());
-				.verify(&Proof::new(vec![0xffff; 42]), 75)
-		);
 		// wrong data for proof
-		assert!(
+		cuckoo_ctx.set_header_nonce([50].to_vec(), None, false)?;
-			!Cuckoo::from_hash(blake2(&[50]).as_bytes(), 20)
+		assert!(!cuckoo_ctx.verify(&Proof::new(V1.to_vec().clone())).is_ok());
-				.verify(&Proof::new(V1.to_vec().clone()), 75)
-		);
 		let mut test_header = [0; 32];
 		test_header[0] = 24;
-		assert!(
+		let mut cuckoo_ctx = CuckooContext::<T>::new(20, 42, 50, 10)?;
-			!Cuckoo::from_hash(blake2(&test_header).as_bytes(), 20)
+		cuckoo_ctx.set_header_nonce(test_header.to_vec(), None, false)?;
-				.verify(&Proof::new(V4.to_vec().clone()), 50)
+		assert!(!cuckoo_ctx.verify(&Proof::new(V4.to_vec().clone())).is_ok());
-		);
+		Ok(())
 	}
 
-	#[test]
+	fn mine16_validate<T>() -> Result<(), Error>
-	fn mine20_validate() {
+	where
-		// cuckoo20
+		T: EdgeType,
+	{
 		for n in 1..5 {
 			let h = [n; 32];
-			let nonces = Miner::from_hash(&h, 75, 42, 20).mine().unwrap();
+			let mut cuckoo_ctx = CuckooContext::<T>::new(16, 42, 75, 10)?;
-			assert!(Cuckoo::from_hash(&h, 20).verify(&nonces, 75));
+			cuckoo_ctx.set_header_nonce(h.to_vec(), None, false)?;
-		}
+			let res = cuckoo_ctx.find_cycles()?;
-		// cuckoo18
+			assert!(cuckoo_ctx.verify(&res[0]).is_ok())
-		for n in 1..5 {
-			let h = [n; 32];
-			let nonces = Miner::from_hash(&h, 75, 42, 18).mine().unwrap();
-			assert!(Cuckoo::from_hash(&h, 18).verify(&nonces, 75));
 		}
+		Ok(())
 	}
 }

core/src/pow/error.rs

@@ -0,0 +1,106 @@
+// Copyright 2018 The Grin Developers
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Cuckatoo specific errors
+use failure::{Backtrace, Context, Fail};
+use std::fmt::{self, Display};
+use std::io;
+
+/// Cuckatoo solver or validation error
+#[derive(Debug)]
+pub struct Error {
+	inner: Context<ErrorKind>,
+}
+
+#[derive(Clone, Debug, Eq, Fail, PartialEq)]
+/// Libwallet error types
+pub enum ErrorKind {
+	/// Verification error
+	#[fail(display = "Verification Error: {}", _0)]
+	Verification(String),
+	/// Failure to cast from/to generic integer type
+	#[fail(display = "IntegerCast")]
+	IntegerCast,
+	/// IO Error
+	#[fail(display = "IO Error")]
+	IOError,
+	/// Unexpected Edge Error
+	#[fail(display = "Edge Addition Error")]
+	EdgeAddition,
+	/// Path Error
+	#[fail(display = "Path Error")]
+	Path,
+	/// Invalid cycle
+	#[fail(display = "Invalid Cycle length: {}", _0)]
+	InvalidCycle(usize),
+	/// No Cycle
+	#[fail(display = "No Cycle")]
+	NoCycle,
+	/// No Solution
+	#[fail(display = "No Solution")]
+	NoSolution,
+}
+
+impl Fail for Error {
+	fn cause(&self) -> Option<&Fail> {
+		self.inner.cause()
+	}
+
+	fn backtrace(&self) -> Option<&Backtrace> {
+		self.inner.backtrace()
+	}
+}
+
+impl Display for Error {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		Display::fmt(&self.inner, f)
+	}
+}
+
+impl Error {
+	/// Return errorkind
+	pub fn kind(&self) -> ErrorKind {
+		self.inner.get_context().clone()
+	}
+}
+
+impl From<ErrorKind> for Error {
+	fn from(kind: ErrorKind) -> Error {
+		Error {
+			inner: Context::new(kind),
+		}
+	}
+}
+
+impl From<Context<ErrorKind>> for Error {
+	fn from(inner: Context<ErrorKind>) -> Error {
+		Error { inner: inner }
+	}
+}
+
+impl From<fmt::Error> for Error {
+	fn from(_error: fmt::Error) -> Error {
+		Error {
+			inner: Context::new(ErrorKind::IntegerCast),
+		}
+	}
+}
+
+impl From<io::Error> for Error {
+	fn from(_error: io::Error) -> Error {
+		Error {
+			inner: Context::new(ErrorKind::IOError),
+		}
+	}
+}

core/src/pow/mod.rs

@@ -30,12 +30,17 @@
 
 extern crate blake2_rfc as blake2;
 extern crate chrono;
+extern crate num;
 extern crate rand;
 extern crate serde;
 
 extern crate grin_util as util;
 
+#[macro_use]
+mod common;
+pub mod cuckatoo;
 pub mod cuckoo;
+mod error;
 mod siphash;
 mod types;
 
@@ -44,15 +49,26 @@ use consensus;
 use core::{Block, BlockHeader};
 use genesis;
 use global;
-use pow::cuckoo::{Cuckoo, Error};
 
+pub use self::common::EdgeType;
 pub use self::types::*;
+pub use pow::cuckatoo::CuckatooContext;
+pub use pow::cuckoo::CuckooContext;
+pub use pow::error::Error;
+
+const MAX_SOLS: u32 = 10;
 
 /// 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: u8) -> bool {
+pub fn verify_size(bh: &BlockHeader, cuckoo_sz: u8) -> Result<(), Error> {
-	Cuckoo::from_hash(bh.pre_pow_hash().as_ref(), cuckoo_sz)
+	let mut ctx = global::create_pow_context::<u64>(
-		.verify(&bh.pow.proof, consensus::EASINESS as u64)
+		cuckoo_sz,
+		bh.pow.proof.nonces.len(),
+		consensus::EASINESS,
+		MAX_SOLS,
+	)?;
+	ctx.set_header_nonce(bh.pre_pow(), None, false)?;
+	ctx.verify(&bh.pow.proof)
 }
 
 /// Mines a genesis block using the internal miner
@@ -69,7 +85,7 @@ pub fn mine_genesis_block() -> Result<Block, Error> {
 	let sz = global::min_sizeshift();
 	let proof_size = global::proofsize();
 
-	pow_size(&mut gen.header, genesis_difficulty, proof_size, sz).unwrap();
+	pow_size(&mut gen.header, genesis_difficulty, proof_size, sz)?;
 	Ok(gen)
 }
 
@@ -93,8 +109,11 @@ pub fn pow_size(
 	loop {
 		// if we found a cycle (not guaranteed) and the proof hash is higher that the
 		// diff, we're all good
-		if let Ok(proof) = cuckoo::Miner::new(bh, consensus::EASINESS, proof_size, sz).mine() {
+		let mut ctx =
-			bh.pow.proof = proof;
+			global::create_pow_context::<u32>(sz, proof_size, consensus::EASINESS, MAX_SOLS)?;
+		ctx.set_header_nonce(bh.pre_pow(), None, true)?;
+		if let Ok(proofs) = ctx.find_cycles() {
+			bh.pow.proof = proofs[0].clone();
 			if bh.pow.to_difficulty() >= diff {
 				return Ok(());
 			}
@@ -132,6 +151,6 @@ mod test {
 		).unwrap();
 		assert!(b.header.pow.nonce != 310);
 		assert!(b.header.pow.to_difficulty() >= Difficulty::one());
-		assert!(verify_size(&b.header, global::min_sizeshift()));
+		assert!(verify_size(&b.header, global::min_sizeshift()).is_ok());
 	}
 }

core/src/pow/siphash.rs

@@ -16,7 +16,7 @@
 //! Jean-Philippe Aumasson and Daniel J. Bernstein.
 
 /// Implements siphash 2-4 specialized for a 4 u64 array key and a u64 nonce
-pub fn siphash24(v: [u64; 4], nonce: u64) -> u64 {
+pub fn siphash24(v: &[u64; 4], nonce: u64) -> u64 {
 	let mut v0 = v[0];
 	let mut v1 = v[1];
 	let mut v2 = v[2];
@@ -73,9 +73,9 @@ mod test {
 	/// the fact that the Java impl uses a long, aka a signed 64 bits number).
 	#[test]
 	fn hash_some() {
-		assert_eq!(siphash24([1, 2, 3, 4], 10), 928382149599306901);
+		assert_eq!(siphash24(&[1, 2, 3, 4], 10), 928382149599306901);
-		assert_eq!(siphash24([1, 2, 3, 4], 111), 10524991083049122233);
+		assert_eq!(siphash24(&[1, 2, 3, 4], 111), 10524991083049122233);
-		assert_eq!(siphash24([9, 7, 6, 7], 12), 1305683875471634734);
+		assert_eq!(siphash24(&[9, 7, 6, 7], 12), 1305683875471634734);
-		assert_eq!(siphash24([9, 7, 6, 7], 10), 11589833042187638814);
+		assert_eq!(siphash24(&[9, 7, 6, 7], 10), 11589833042187638814);
 	}
 }

core/src/pow/types.rs

@@ -26,6 +26,36 @@ use core::hash::Hashed;
 use global;
 use ser::{self, Readable, Reader, Writeable, Writer};
 
+use pow::common::EdgeType;
+use pow::error::Error;
+
+/// Generic trait for a solver/verifier providing common interface into Cuckoo-family PoW
+/// Mostly used for verification, but also for test mining if necessary
+pub trait PoWContext<T>
+where
+	T: EdgeType,
+{
+	/// Create new instance of context with appropriate parameters
+	fn new(
+		edge_bits: u8,
+		proof_size: usize,
+		easiness_pct: u32,
+		max_sols: u32,
+	) -> Result<Box<Self>, Error>;
+	/// Sets the header along with an optional nonce at the end
+	/// solve: whether to set up structures for a solve (true) or just validate (false)
+	fn set_header_nonce(
+		&mut self,
+		header: Vec<u8>,
+		nonce: Option<u32>,
+		solve: bool,
+	) -> Result<(), Error>;
+	/// find solutions using the stored parameters and header
+	fn find_cycles(&mut self) -> Result<Vec<Proof>, Error>;
+	/// Verify a solution with the stored parameters
+	fn verify(&self, proof: &Proof) -> Result<(), Error>;
+}
+
 /// The difficulty is defined as the maximum target divided by the block hash.
 #[derive(Debug, Clone, Copy, PartialEq, PartialOrd, Eq, Ord)]
 pub struct Difficulty {

servers/src/common/types.rs

@@ -42,7 +42,7 @@ pub enum Error {
 	/// Error originating from wallet API.
 	Wallet(wallet::Error),
 	/// Error originating from the cuckoo miner
-	Cuckoo(pow::cuckoo::Error),
+	Cuckoo(pow::Error),
 }
 
 impl From<core::block::Error> for Error {
@@ -62,8 +62,8 @@ impl From<p2p::Error> for Error {
 	}
 }
 
-impl From<pow::cuckoo::Error> for Error {
+impl From<pow::Error> for Error {
-	fn from(e: pow::cuckoo::Error) -> Error {
+	fn from(e: pow::Error) -> Error {
 		Error::Cuckoo(e)
 	}
 }

servers/src/mining/stratumserver.rs

@@ -529,7 +529,7 @@ impl StratumServer {
 			);
 		} else {
 			// Do some validation but dont submit
-			if !pow::verify_size(&b.header, global::min_sizeshift()) {
+			if !pow::verify_size(&b.header, global::min_sizeshift()).is_ok() {
 				// Return error status
 				error!(
 					LOGGER,

servers/src/mining/test_miner.rs

@@ -26,7 +26,7 @@ use common::types::StratumServerConfig;
 use core::core::hash::{Hash, Hashed};
 use core::core::verifier_cache::VerifierCache;
 use core::core::{Block, BlockHeader};
-use core::pow::cuckoo;
+use core::pow::PoWContext;
 use core::{consensus, global};
 use mining::mine_block;
 use pool;
@@ -96,14 +96,16 @@ impl Miner {
 		let mut iter_count = 0;
 
 		while head.hash() == *latest_hash && Utc::now().timestamp() < deadline {
-			if let Ok(proof) = cuckoo::Miner::new(
+			let mut ctx = global::create_pow_context::<u32>(
-				&b.header,
-				consensus::EASINESS,
-				global::proofsize(),
 				global::min_sizeshift(),
-			).mine()
+				global::proofsize(),
-			{
+				consensus::EASINESS,
-				b.header.pow.proof = proof;
+				10,
+			).unwrap();
+			ctx.set_header_nonce(b.header.pre_pow(), None, true)
+				.unwrap();
+			if let Ok(proofs) = ctx.find_cycles() {
+				b.header.pow.proof = proofs[0].clone();
 				let proof_diff = b.header.pow.to_difficulty();
 				if proof_diff >= (b.header.total_difficulty() - head.total_difficulty()) {
 					return true;