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// Copyright 2017 The Exonum Team // // 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. //! Messages used in the Exonum consensus algorithm. //! //! Every message, unless stated otherwise, is checked by the same set of rules. The message is //! ignored if it //! * is sent from a lower height than the current one //! * contains incorrect validator id //! * is signed with incorrect signature //! //! Specific nuances are described in each message documentation and typically consist of three //! parts: //! * validation - additional checks before processing //! * processing - how message is processed and result of the processing //! * generation - in which cases message is generated use std::net::SocketAddr; use std::time::SystemTime; use crypto::{Hash, PublicKey}; use blockchain; use helpers::{Height, Round, ValidatorId}; use super::{RawMessage, BitVec}; /// Consensus message type. pub const CONSENSUS: u16 = 0; /// `Connect` message id. pub const CONNECT_MESSAGE_ID: u16 = 0; /// `Status` message id. pub const STATUS_MESSAGE_ID: u16 = 1; /// `Propose` message id. pub const PROPOSE_MESSAGE_ID: u16 = 2; /// `Prevote` message id. pub const PREVOTE_MESSAGE_ID: u16 = 3; /// `Precommit` message id. pub const PRECOMMIT_MESSAGE_ID: u16 = 4; /// `BlockResponse` message id. pub const BLOCK_RESPONSE_MESSAGE_ID: u16 = 5; /// `ProposeRequest` message id. pub const PROPOSE_REQUEST_MESSAGE_ID: u16 = 6; /// `TransactionsRequest` message id. pub const TRANSACTIONS_REQUEST_MESSAGE_ID: u16 = 7; /// `PrevotesRequest` message id. pub const PREVOTES_REQUEST_MESSAGE_ID: u16 = 8; /// `PeersRequest` message id. pub const PEERS_REQUEST_MESSAGE_ID: u16 = 9; /// `BlockRequest` message id. pub const BLOCK_REQUEST_MESSAGE_ID: u16 = 10; message! { /// Connect to a node. /// /// ### Validation /// The message is ignored if its time is earlier than in the previous `Connect` message received /// from the same peer. /// /// ### Processing /// Connect to the peer. /// /// ### Generation /// A node sends `Connect` message to all known addresses during initialization. Additionally, /// the node responds by its own `Connect` message after receiving `node::Event::Connected`. struct Connect { const TYPE = CONSENSUS; const ID = CONNECT_MESSAGE_ID; const SIZE = 50; /// The sender's public key. field pub_key: &PublicKey [00 => 32] /// The node's address. field addr: SocketAddr [32 => 38] /// Time when the message was created. field time: SystemTime [38 => 50] } } message! { /// Proposal for a new block. /// /// ### Validation /// The message is ignored if it /// * contains incorrect `prev_hash` /// * is sent by non-leader /// * contains already committed transactions /// * is already known /// /// ### Processing /// If the message contains unknown transactions, then `TransactionsRequest` is sent in reply. /// Otherwise `Prevote` is broadcast. /// /// ### Generation /// A node broadcasts `Propose` if it is a leader and is not locked for a different proposal. Also /// `Propose` can be sent as response to `ProposeRequest`. struct Propose { const TYPE = CONSENSUS; const ID = PROPOSE_MESSAGE_ID; const SIZE = 54; /// The validator id. field validator: ValidatorId [00 => 02] /// The height to which the message is related. field height: Height [02 => 10] /// The round to which the message is related. field round: Round [10 => 14] /// Hash of the previous block. field prev_hash: &Hash [14 => 46] /// The list of transactions to include in the next block. field transactions: &[Hash] [46 => 54] } } message! { /// Pre-vote for a new block. /// /// ### Validation /// A node panics if it has already sent a different `Prevote` for the same round. /// /// ### Processing /// Pre-vote is added to the list of known votes for the same proposal. /// If `locked_round` number from the message is bigger than in a node state, then a node replies /// with `PrevotesRequest`. /// If there are unknown transactions in the propose specified by `propose_hash`, /// `TransactionsRequest` is sent in reply. /// Otherwise if all transactions are known and there are +2/3 pre-votes, then a node is locked /// to that proposal and `Precommit` is broadcast. /// /// ### Generation /// A node broadcasts `Prevote` in response to `Propose` when it has received all the transactions. struct Prevote { const TYPE = CONSENSUS; const ID = PREVOTE_MESSAGE_ID; const SIZE = 50; /// The validator id. field validator: ValidatorId [00 => 02] /// The height to which the message is related. field height: Height [02 => 10] /// The round to which the message is related. field round: Round [10 => 14] /// Hash of the corresponding `Propose`. field propose_hash: &Hash [14 => 46] /// Locked round. field locked_round: Round [46 => 50] } } message! { /// Pre-commit for a proposal. /// /// ### Validation /// A node panics if it has already sent a different `Precommit` for the same round. /// /// ### Processing /// Pre-commit is added to the list of known pre-commits. /// If a proposal is unknown to the node, `ProposeRequest` is sent in reply. /// If `round` number from the message is bigger than a node's "locked round", then a node replies /// with `PrevotesRequest`. /// If there are unknown transactions, then `TransactionsRequest` is sent in reply. /// If a validator receives +2/3 precommits for the same proposal with the same block_hash, then /// block is executed and `Status` is broadcast. /// /// ### Generation /// A node broadcasts `Precommit` in response to `Prevote` if there are +2/3 pre-votes and no /// unknown transactions. struct Precommit { const TYPE = CONSENSUS; const ID = PRECOMMIT_MESSAGE_ID; const SIZE = 90; /// The validator id. field validator: ValidatorId [00 => 02] /// The height to which the message is related. field height: Height [02 => 10] /// The round to which the message is related. field round: Round [10 => 14] /// Hash of the corresponding `Propose`. field propose_hash: &Hash [14 => 46] /// Hash of the new block. field block_hash: &Hash [46 => 78] /// Time of the `Precommit`. field time: SystemTime [78 => 90] } } message! { /// Current node status. /// /// ### Validation /// The message is ignored if its signature is incorrect or its `height` is lower than a node's /// height. /// /// ### Processing /// If the message's `height` number is bigger than a node's one, then `BlockRequest` with current /// node's height is sent in reply. /// /// ### Generation /// `Status` message is broadcast regularly with the timeout controlled by /// `blockchain::ConsensusConfig::status_timeout`. Also, it is broadcast after accepting a new /// block. struct Status { const TYPE = CONSENSUS; const ID = STATUS_MESSAGE_ID; const SIZE = 72; /// The sender's public key. field from: &PublicKey [00 => 32] /// The height to which the message is related. field height: Height [32 => 40] /// Hash of the last committed block. field last_hash: &Hash [40 => 72] } } message! { /// Information about a block. /// /// ### Validation /// The message is ignored if /// * its `to` field corresponds to a different node /// * the `block`, `transaction` and `precommits` fields cannot be parsed or verified /// /// ### Processing /// The block is added to the blockchain. /// /// ### Generation /// The message is sent as response to `BlockRequest`. struct BlockResponse { const TYPE = CONSENSUS; const ID = BLOCK_RESPONSE_MESSAGE_ID; const SIZE = 88; /// The sender's public key. field from: &PublicKey [00 => 32] /// Public key of the recipient. field to: &PublicKey [32 => 64] /// Block header. field block: blockchain::Block [64 => 72] /// List of pre-commits. field precommits: Vec<Precommit> [72 => 80] /// List of the transactions. field transactions: Vec<RawMessage> [80 => 88] } } message! { /// Request for the `Propose`. /// /// ### Validation /// The message is ignored if its `height` is not equal to the node's height. /// /// ### Processing /// `Propose` is sent as the response. /// /// ### Generation /// A node can send `ProposeRequest` during `Precommit` and `Prevote` handling. struct ProposeRequest { const TYPE = CONSENSUS; const ID = PROPOSE_REQUEST_MESSAGE_ID; const SIZE = 104; /// The sender's public key. field from: &PublicKey [00 => 32] /// Public key of the recipient. field to: &PublicKey [32 => 64] /// The height to which the message is related. field height: Height [64 => 72] /// Hash of the `Propose`. field propose_hash: &Hash [72 => 104] } } message! { /// Request for transactions by hash. /// /// ### Processing /// Requested transactions are sent to the recipient. /// /// ### Generation /// This message can be sent during `Propose`, `Prevote` and `Precommit` handling. struct TransactionsRequest { const TYPE = CONSENSUS; const ID = TRANSACTIONS_REQUEST_MESSAGE_ID; const SIZE = 72; /// The sender's public key. field from: &PublicKey [00 => 32] /// Public key of the recipient. field to: &PublicKey [32 => 64] /// The list of the transaction hashes. field txs: &[Hash] [64 => 72] } } message! { /// Request for pre-votes. /// /// ### Validation /// The message is ignored if its `height` is not equal to the node's height. /// /// ### Processing /// The requested pre-votes are sent to the recipient. /// /// ### Generation /// This message can be sent during `Prevote` and `Precommit` handling. struct PrevotesRequest { const TYPE = CONSENSUS; const ID = PREVOTES_REQUEST_MESSAGE_ID; const SIZE = 116; /// The sender's public key. field from: &PublicKey [00 => 32] /// Public key of the recipient. field to: &PublicKey [32 => 64] /// The height to which the message is related. field height: Height [64 => 72] /// The round to which the message is related. field round: Round [72 => 76] /// Hash of the `Propose`. field propose_hash: &Hash [76 => 108] /// The list of validators that send pre-votes. field validators: BitVec [108 => 116] } } message! { /// Request connected peers from a node. /// /// ### Validation /// Request is considered valid if the sender of the message on the network level corresponds to /// the `from` field. /// /// ### Processing /// Peer `Connect` messages are sent to the recipient. /// /// ### Generation /// `PeersRequest` message is sent regularly with the timeout controlled by /// `blockchain::ConsensusConfig::peers_timeout`. struct PeersRequest { const TYPE = CONSENSUS; const ID = PEERS_REQUEST_MESSAGE_ID; const SIZE = 64; /// The sender's public key. field from: &PublicKey [00 => 32] /// Public key of the recipient. field to: &PublicKey [32 => 64] } } message! { /// Request for the block with the given `height`. /// /// ### Validation /// The message is ignored if its `height` is bigger than the node's one. /// /// ### Processing /// `BlockResponse` message is sent as the response. /// /// ### Generation /// This message can be sent during `Status` processing. struct BlockRequest { const TYPE = CONSENSUS; const ID = BLOCK_REQUEST_MESSAGE_ID; const SIZE = 72; /// The sender's public key. field from: &PublicKey [00 => 32] /// Public key of the recipient. field to: &PublicKey [32 => 64] /// The height to which the message is related. field height: Height [64 => 72] } }