LES Part 1 (#3322)

* stub implementations of light client trait

* Light provider trait

* light client sync stubs

* LES boilerplate

* stub implementation of provider for client

* skeleton and request traits

* request definitions

* new_list -> begin_list

* handle unknown packet

* revise light implementation strategy

* make verification module public

* Move all light client work to own crate

* experiment with answering requests

* buffer flow scaffolding

* remove LESv2 requests

* buffer flow basics, implement cost table

* begin status module

* implement handshake parsing and creation

* implement announcement serialization

* errors, punishment, and handshake

* handle announcements

* making announcements, clean up warnings

* allow dead code temporarily

ethcore/light/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+description = "Parity LES primitives"
+homepage = "https://ethcore.io"
+license = "GPL-3.0"
+name = "ethcore-light"
+version = "1.5.0"
+authors = ["Ethcore <admin@ethcore.io>"]
+
+[dependencies]
+log = "0.3"
+ethcore = { path = ".." }
+ethcore-util = { path = "../../util" }
+ethcore-network = { path = "../../util/network" }
+ethcore-io = { path = "../../util/io" }
+rlp = { path = "../../util/rlp" }
+time = "0.1"

ethcore/light/src/client.rs

@@ -0,0 +1,115 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Light client implementation. Used for raw data queries as well as the header
+//! sync.
+
+use std::sync::Arc;
+
+use ethcore::engines::Engine;
+use ethcore::ids::BlockID;
+use ethcore::service::ClientIoMessage;
+use ethcore::block_import_error::BlockImportError;
+use ethcore::block_status::BlockStatus;
+use ethcore::verification::queue::{HeaderQueue, QueueInfo};
+use ethcore::transaction::SignedTransaction;
+use ethcore::blockchain_info::BlockChainInfo;
+
+use io::IoChannel;
+use util::hash::H256;
+use util::{Bytes, Mutex};
+
+use provider::Provider;
+use request;
+
+/// Light client implementation.
+pub struct Client {
+	engine: Arc<Engine>,
+	header_queue: HeaderQueue,
+	message_channel: Mutex<IoChannel<ClientIoMessage>>,
+}
+
+impl Client {
+	/// Import a header as rlp-encoded bytes.
+	pub fn import_header(&self, bytes: Bytes) -> Result<H256, BlockImportError> {
+		let header = ::rlp::decode(&bytes);
+
+		self.header_queue.import(header).map_err(Into::into)
+	}
+
+	/// Whether the block is already known (but not necessarily part of the canonical chain)
+	pub fn is_known(&self, _id: BlockID) -> bool {
+		false
+	}
+
+	/// Fetch a vector of all pending transactions.
+	pub fn pending_transactions(&self) -> Vec<SignedTransaction> {
+		vec![]
+	}
+
+	/// Inquire about the status of a given block.
+	pub fn status(&self, _id: BlockID) -> BlockStatus {
+		BlockStatus::Unknown
+	}
+
+	/// Get the header queue info.
+	pub fn queue_info(&self) -> QueueInfo {
+		self.header_queue.queue_info()
+	}
+}
+
+// dummy implementation -- may draw from canonical cache further on.
+impl Provider for Client {
+	fn chain_info(&self) -> BlockChainInfo {
+		unimplemented!()
+	}
+
+	fn reorg_depth(&self, _a: &H256, _b: &H256) -> Option<u64> {
+		None
+	}
+
+	fn earliest_state(&self) -> Option<u64> {
+		None
+	}
+
+	fn block_headers(&self, _req: request::Headers) -> Vec<Bytes> {
+		Vec::new()
+	}
+
+	fn block_bodies(&self, _req: request::Bodies) -> Vec<Bytes> {
+		Vec::new()
+	}
+
+	fn receipts(&self, _req: request::Receipts) -> Vec<Bytes> {
+		Vec::new()
+	}
+
+	fn proofs(&self, _req: request::StateProofs) -> Vec<Bytes> {
+		Vec::new()
+	}
+
+	fn code(&self, _req: request::ContractCodes) -> Vec<Bytes> {
+		Vec::new()
+	}
+
+	fn header_proofs(&self, _req: request::HeaderProofs) -> Vec<Bytes> {
+		Vec::new()
+	}
+
+	fn pending_transactions(&self) -> Vec<SignedTransaction> {
+		Vec::new()
+	}
+}

ethcore/light/src/lib.rs

@@ -0,0 +1,47 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Light client logic and implementation.
+//!
+//! A "light" client stores very little chain-related data locally
+//! unlike a full node, which stores all blocks, headers, receipts, and more.
+//!
+//! This enables the client to have a much lower resource footprint in
+//! exchange for the cost of having to ask the network for state data
+//! while responding to queries. This makes a light client unsuitable for
+//! low-latency applications, but perfectly suitable for simple everyday
+//! use-cases like sending transactions from a personal account.
+//!
+//! It starts by performing a header-only sync, verifying random samples
+//! of members of the chain to varying degrees.
+
+// TODO: remove when integrating with parity.
+#![allow(dead_code)]
+
+pub mod client;
+pub mod net;
+pub mod provider;
+pub mod request;
+
+extern crate ethcore_util as util;
+extern crate ethcore_network as network;
+extern crate ethcore_io as io;
+extern crate ethcore;
+extern crate rlp;
+extern crate time;
+
+#[macro_use]
+extern crate log;