Miner facility, using the current chain state to build on top of.

chain/Cargo.toml

@@ -6,6 +6,7 @@ authors = ["Ignotus Peverell <igno.peverell@protonmail.com>"]
 [dependencies]
 bitflags = "^0.7.0"
 byteorder = "^0.5"
+time = "^0.1"
 
 grin_core = { path = "../core" }
 grin_store = { path = "../store" }

chain/src/lib.rs

@@ -23,6 +23,7 @@
 #[macro_use]
 extern crate bitflags;
 extern crate byteorder;
+extern crate time;
 
 extern crate grin_core as core;
 extern crate grin_store;
@@ -34,6 +35,5 @@ pub mod types;
 
 // Re-export the base interface
 
-pub use types::ChainStore;
+pub use types::{ChainStore, State, Tip};
-pub use pipe::Options;
+pub use pipe::{NONE, process_block};
-pub use pipe::process_block;

chain/src/pipe.rs

@@ -15,6 +15,7 @@
 //! Implementation of the chain block acceptance (or refusal) pipeline.
 
 use secp;
+use time;
 
 use core::consensus;
 use core::core::hash::Hash;
@@ -27,8 +28,9 @@ use store;
 bitflags! {
   /// Options for block validation
   pub flags Options: u32 {
+    const NONE = 0b00000001,
     /// Runs with the easier version of the Proof of Work, mostly to make testing easier.
-    const EASY_POW = 0b00000001,
+    const EASY_POW = 0b00000010,
   }
 }
 
@@ -89,18 +91,23 @@ pub fn process_block(b: &Block, store: &ChainStore, opts: Options) -> Result<(),
 /// First level of black validation that only needs to act on the block header
 /// to make it as cheap as possible. The different validations are also
 /// arranged by order of cost to have as little DoS surface as possible.
-/// TODO actually require only the block header (with length information)
+/// TODO require only the block header (with length information)
 fn validate_header(b: &Block, ctx: &mut BlockContext) -> Result<(), Error> {
 	let header = &b.header;
 	if header.height > ctx.head.height + 1 {
 		// TODO actually handle orphans and add them to a size-limited set
 		return Err(Error::Unfit("orphan".to_string()));
 	}
-	// TODO check time wrt to chain time, refuse too far in future
 
 	let prev = try!(ctx.store.get_block_header(&header.previous).map_err(&Error::StoreErr));
 
 	if header.timestamp <= prev.timestamp {
+    // prevent time warp attacks and some timestamp manipulations by forcing strict time progression
+		return Err(Error::InvalidBlockTime);
+	}
+  if header.timestamp > time::now() + time::Duration::seconds(12*(consensus::BLOCK_TIME_SEC as i64)) {
+    // refuse blocks too far in future, constant of 12 comes from bitcoin (2h worth of blocks)
+    // TODO add warning in p2p code if local time is too different from peers
 		return Err(Error::InvalidBlockTime);
   }
 

chain/src/store.rs

@@ -48,6 +48,11 @@ impl ChainStore for ChainKVStore {
 		option_to_not_found(self.db.get_ser(&vec![HEAD_PREFIX]))
 	}
 
+  fn head_header(&self) -> Result<BlockHeader, Error> {
+		let head: Tip = try!(option_to_not_found(self.db.get_ser(&vec![HEAD_PREFIX])));
+    self.get_block_header(&head.last_block_h)
+  }
+
 	fn save_block(&self, b: &Block) -> Result<(), Error> {
 		try!(self.db
 			.put_ser(&to_key(BLOCK_PREFIX, &mut b.hash().to_vec())[..], b)

chain/src/types.rs

@@ -131,12 +131,21 @@ pub enum Error {
 	StorageErr(String),
 }
 
+#[derive(Debug, Clone)]
+pub struct State {
+  pub head: Tip,
+  pub forks: Vec<Tip>,
+}
+
 /// Trait the chain pipeline requires an implementor for in order to process
 /// blocks.
 pub trait ChainStore {
 	/// Get the tip that's also the head of the chain
 	fn head(&self) -> Result<Tip, Error>;
 
+  /// Block header for the chain head
+  fn head_header(&self) -> Result<BlockHeader, Error>;
+
 	/// Gets a block header by hash
 	fn get_block_header(&self, h: &Hash) -> Result<BlockHeader, Error>;
 
@@ -149,3 +158,4 @@ pub trait ChainStore {
 	/// Save the provided tip without setting it as head
 	fn save_tip(&self, t: &Tip) -> Result<(), Error>;
 }
+

core/src/pow/cuckoo.rs

@@ -76,14 +76,14 @@ impl Cuckoo {
 	/// 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).
-	pub fn new_node(&self, nonce: u64, uorv: u64) -> u64 {
+	fn new_node(&self, nonce: u64, uorv: u64) -> u64 {
 		return ((siphash24(self.v, 2 * nonce + uorv) & self.mask) << 1) | uorv;
 	}
 
 	/// 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.
-	pub fn new_edge(&self, nonce: u64) -> Edge {
+	fn new_edge(&self, nonce: u64) -> Edge {
 		Edge {
 			u: self.new_node(nonce, 0),
 			v: self.new_node(nonce, 1),

core/src/pow/mod.rs

@@ -23,7 +23,7 @@
 //! reference. It's not optimized for speed.
 
 mod siphash;
-mod cuckoo;
+pub mod cuckoo;
 
 use time;
 
@@ -41,7 +41,7 @@ use ser::{Writeable, Writer};
 /// difficulty (yet unknown). We also add the count of every variable length
 /// elements in a header to make lying on those much harder.
 #[derive(Debug)]
-struct PowHeader {
+pub struct PowHeader {
 	pub nonce: u64,
 	pub height: u64,
 	pub previous: Hash,
@@ -71,7 +71,7 @@ impl Writeable for PowHeader {
 }
 
 impl PowHeader {
-	fn from_block(b: &Block) -> PowHeader {
+	pub fn from_block(b: &Block) -> PowHeader {
 		let ref h = b.header;
 		PowHeader {
 			nonce: h.nonce,

grin/Cargo.toml

@@ -4,5 +4,12 @@ version = "0.1.0"
 authors = ["Ignotus Peverell <igno.peverell@protonmail.com>"]
 
 [dependencies]
+grin_chain = { path = "../chain" }
 grin_core = { path = "../core" }
 grin_store = { path = "../store" }
+secp256k1zkp = { path = "../secp256k1zkp" }
+
+env_logger="^0.3.5"
+log = "^0.3"
+time = "^0.1"
+rand = "^0.3"

grin/src/main.rs

@@ -21,13 +21,25 @@
 #![deny(unused_mut)]
 #![warn(missing_docs)]
 
+#[macro_use]
+extern crate log;
+extern crate env_logger;
+extern crate rand;
+extern crate time;
+
+extern crate grin_chain as chain;
 extern crate grin_core as core;
 extern crate grin_store as store;
+extern crate secp256k1zkp as secp;
+
+mod miner;
 
 use store::Store;
 use core::genesis::genesis;
 
 fn main() {
+  env_logger::init().unwrap();
+
 	let gen = genesis();
 	let db = Store::open("./store").unwrap();
 	let mut key = "block:".to_string().into_bytes();

grin/src/miner.rs

@@ -0,0 +1,111 @@
+// Copyright 2016 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.
+
+//! Mining service, gathers transactions from the pool, assemble them in a block and mine the block to produce a valid header with its proof-of-work.
+
+use rand::{self, Rng};
+use std::sync::{Arc, Mutex};
+use std::ops::Deref;
+use time;
+
+use core::consensus;
+use core::core;
+use core::core::hash::{Hash, Hashed};
+use core::pow;
+use core::pow::cuckoo;
+use chain;
+use secp;
+
+pub struct Miner {
+  chain_state: Arc<Mutex<chain::State>>,
+  chain_store: Arc<Mutex<chain::ChainStore>>,
+}
+
+impl Miner {
+  /// Creates a new Miner. Needs references to the chain state and its storage.
+  pub fn new(chain_state: Arc<Mutex<chain::State>>, chain_store: Arc<Mutex<chain::ChainStore>>) -> Miner {
+    Miner{chain_state: chain_state, chain_store: chain_store}
+  }
+
+  /// Starts the mining loop, building a new block on top of the existing chain anytime required and looking for PoW solution.
+  pub fn run_loop(&self) {
+    loop {
+      // get the latest chain state and build a block on top of it
+      let head: core::BlockHeader;
+      let mut latest_hash: Hash;
+      {
+        head = self.chain_store.lock().unwrap().head_header().unwrap();
+        latest_hash = self.chain_state.lock().unwrap().head.last_block_h;
+      }
+      let b = self.build_block(&head);
+      let mut pow_header = pow::PowHeader::from_block(&b);
+
+      // look for a pow for at most 2 sec on the same block (to give a chance to new transactions) and as long as the head hasn't changed
+      let deadline = time::get_time().sec + 2;
+      let mut sol = None;
+      while head.hash() == latest_hash && time::get_time().sec < deadline {
+		    let pow_hash = pow_header.hash();
+        let mut miner = cuckoo::Miner::new(pow_hash.to_slice(), consensus::EASINESS, b.header.cuckoo_len as u32);
+        if let Ok(proof) = miner.mine() {
+          if proof.to_target() <= b.header.target {
+            sol = Some(proof);
+            break;
+          }
+        }
+		    pow_header.nonce += 1;
+        {
+          latest_hash = self.chain_state.lock().unwrap().head.last_block_h;
+        }
+      }
+
+      // if we found a solution, push our block out
+      if let Some(proof) = sol {
+        if let Err(e) = chain::process_block(&b, self.chain_store.lock().unwrap().deref(), chain::NONE) {
+          error!("Error validating mined block: {:?}", e);
+        }
+      }
+    }
+  }
+
+  /// Builds a new block with the chain head as previous and eligible transactions from the pool.
+  fn build_block(&self, head: &core::BlockHeader) -> core::Block {
+    let mut now_sec = time::get_time().sec;
+    let head_sec = head.timestamp.to_timespec().sec;
+    if now_sec == head_sec {
+      now_sec += 1;
+    }
+    let (target, cuckoo_len) = consensus::next_target(now_sec, head_sec, head.target, head.cuckoo_len);
+
+		let mut rng = rand::OsRng::new().unwrap();
+		let secp_inst = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);
+    // TODO get a new key from the user's wallet or something
+		let skey = secp::key::SecretKey::new(&secp_inst, &mut rng);
+
+    // TODO populate inputs and outputs from pool transactions
+    core::Block {
+      header: core::BlockHeader {
+        height: head.height+1,
+        previous: head.hash(),
+        timestamp: time::at(time::Timespec::new(now_sec, 0)),
+        cuckoo_len: cuckoo_len,
+        target: target,
+        nonce: rng.gen(),
+				..Default::default()
+      },
+      inputs: vec![],
+      outputs: vec![],
+      proofs: vec![],
+    }
+  }
+}