1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
// Copyright 2015-2017 Parity Technologies (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/>.

/// Validator set maintained in a contract, updated using `getValidators` method.
/// It can also report validators for misbehaviour with two levels: `reportMalicious` and `reportBenign`.

use std::sync::Weak;
use util::*;
use client::{Client, BlockChainClient};
use super::ValidatorSet;
use super::safe_contract::ValidatorSafeContract;

/// The validator contract should have the following interface:
/// [{"constant":true,"inputs":[],"name":"getValidators","outputs":[{"name":"","type":"address[]"}],"payable":false,"type":"function"}]
pub struct ValidatorContract {
	validators: Arc<ValidatorSafeContract>,
	provider: RwLock<Option<provider::Contract>>,
}

impl ValidatorContract {
	pub fn new(contract_address: Address) -> Self {
		ValidatorContract {
			validators: Arc::new(ValidatorSafeContract::new(contract_address)),
			provider: RwLock::new(None),
		}
	}
}

impl ValidatorSet for Arc<ValidatorContract> {
	fn contains(&self, address: &Address) -> bool {
		self.validators.contains(address)
	}

	fn get(&self, nonce: usize) -> Address {
		self.validators.get(nonce)
	}

	fn count(&self) -> usize {
		self.validators.count()
	}

	fn report_malicious(&self, address: &Address) {
		if let Some(ref provider) = *self.provider.read() {
			match provider.report_malicious(address) {
				Ok(_) => warn!(target: "engine", "Reported malicious validator {}", address),
				Err(s) => warn!(target: "engine", "Validator {} could not be reported {}", address, s),
			}
		} else {
			warn!(target: "engine", "Malicious behaviour could not be reported: no provider contract.")
		}
	}

	fn report_benign(&self, address: &Address) {
		if let Some(ref provider) = *self.provider.read() {
			match provider.report_benign(address) {
				Ok(_) => warn!(target: "engine", "Reported benign validator misbehaviour {}", address),
				Err(s) => warn!(target: "engine", "Validator {} could not be reported {}", address, s),
			}
		} else {
			warn!(target: "engine", "Benign misbehaviour could not be reported: no provider contract.")
		}
	}

	fn register_contract(&self, client: Weak<Client>) {
		self.validators.register_contract(client.clone());
		let transact = move |a, d| client
			.upgrade()
			.ok_or("No client!".into())
			.and_then(|c| c.transact_contract(a, d).map_err(|e| format!("Transaction import error: {}", e)))
			.map(|_| Default::default());
		*self.provider.write() = Some(provider::Contract::new(self.validators.address, transact));
	}
}

mod provider {
	// Autogenerated from JSON contract definition using Rust contract convertor.
	#![allow(unused_imports)]
	use std::string::String;
	use std::result::Result;
	use std::fmt;
	use {util, ethabi};
	use util::{FixedHash, Uint};

	pub struct Contract {
		contract: ethabi::Contract,
		address: util::Address,
		do_call: Box<Fn(util::Address, Vec<u8>) -> Result<Vec<u8>, String> + Send + Sync + 'static>,
	}
	impl Contract {
		pub fn new<F>(address: util::Address, do_call: F) -> Self where F: Fn(util::Address, Vec<u8>) -> Result<Vec<u8>, String> + Send + Sync + 'static {
			Contract {
				contract: ethabi::Contract::new(ethabi::Interface::load(b"[{\"constant\":false,\"inputs\":[{\"name\":\"validator\",\"type\":\"address\"}],\"name\":\"reportMalicious\",\"outputs\":[],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"validator\",\"type\":\"address\"}],\"name\":\"reportBenign\",\"outputs\":[],\"payable\":false,\"type\":\"function\"}]").expect("JSON is autogenerated; qed")),
				address: address,
				do_call: Box::new(do_call),
			}
		}
		fn as_string<T: fmt::Debug>(e: T) -> String { format!("{:?}", e) }
		
		/// Auto-generated from: `{"constant":false,"inputs":[{"name":"validator","type":"address"}],"name":"reportMalicious","outputs":[],"payable":false,"type":"function"}`
		#[allow(dead_code)]
		pub fn report_malicious(&self, validator: &util::Address) -> Result<(), String> {
			let call = self.contract.function("reportMalicious".into()).map_err(Self::as_string)?;
			let data = call.encode_call(
				vec![ethabi::Token::Address(validator.clone().0)]
			).map_err(Self::as_string)?;
			call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
			
			Ok(())
		}

		/// Auto-generated from: `{"constant":false,"inputs":[{"name":"validator","type":"address"}],"name":"reportBenign","outputs":[],"payable":false,"type":"function"}`
		#[allow(dead_code)]
		pub fn report_benign(&self, validator: &util::Address) -> Result<(), String> {
			let call = self.contract.function("reportBenign".into()).map_err(Self::as_string)?;
			let data = call.encode_call(
				vec![ethabi::Token::Address(validator.clone().0)]
			).map_err(Self::as_string)?;
			call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
			
			Ok(())
		}
	}
}

#[cfg(test)]
mod tests {
	use util::*;
	use rlp::encode;
	use ethkey::Secret;
	use spec::Spec;
	use header::Header;
	use account_provider::AccountProvider;
	use miner::MinerService;
	use client::BlockChainClient;
	use tests::helpers::generate_dummy_client_with_spec_and_accounts;
	use super::super::ValidatorSet;
	use super::ValidatorContract;

	#[test]
	fn fetches_validators() {
		let client = generate_dummy_client_with_spec_and_accounts(Spec::new_validator_contract, None);
		let vc = Arc::new(ValidatorContract::new(Address::from_str("0000000000000000000000000000000000000005").unwrap()));
		vc.register_contract(Arc::downgrade(&client));
		assert!(vc.contains(&Address::from_str("7d577a597b2742b498cb5cf0c26cdcd726d39e6e").unwrap()));
		assert!(vc.contains(&Address::from_str("82a978b3f5962a5b0957d9ee9eef472ee55b42f1").unwrap()));
	}
	
	#[test]
	fn reports_validators() {
		let tap = Arc::new(AccountProvider::transient_provider());
		let v1 = tap.insert_account(Secret::from_slice(&"1".sha3()).unwrap(), "").unwrap();
		let client = generate_dummy_client_with_spec_and_accounts(Spec::new_validator_contract, Some(tap.clone()));
		client.engine().register_client(Arc::downgrade(&client));
		let validator_contract = Address::from_str("0000000000000000000000000000000000000005").unwrap();

		// Make sure reporting can be done.
		client.miner().set_gas_floor_target(1_000_000.into());

		client.miner().set_engine_signer(v1, "".into()).unwrap();
		let mut header = Header::default();
		let seal = encode(&vec!(5u8)).to_vec();	
		header.set_seal(vec!(seal));
		header.set_author(v1);
		header.set_number(1);
		// `reportBenign` when the designated proposer releases block from the future (bad clock).
		assert!(client.engine().verify_block_unordered(&header, None).is_err());
		// Seal a block.
		client.engine().step();
		assert_eq!(client.chain_info().best_block_number, 1);
		// Check if the unresponsive validator is `disliked`.
		assert_eq!(client.call_contract(validator_contract, "d8f2e0bf".from_hex().unwrap()).unwrap().to_hex(), "0000000000000000000000007d577a597b2742b498cb5cf0c26cdcd726d39e6e");
		// Simulate a misbehaving validator by handling a double proposal.
		assert!(client.engine().verify_block_family(&header, &header, None).is_err());
		// Seal a block.
		client.engine().step();
		client.engine().step();
		assert_eq!(client.chain_info().best_block_number, 2);

		// Check if misbehaving validator was removed.
		client.transact_contract(Default::default(), Default::default()).unwrap();
		client.engine().step();
		client.engine().step();
		assert_eq!(client.chain_info().best_block_number, 2);
	}
}