From 02e347dae1a01172dbcc2efe054014c015d96507 Mon Sep 17 00:00:00 2001 From: Determinant Date: Mon, 16 Jul 2018 19:26:36 -0400 Subject: ... --- include/hotstuff/consensus.h | 250 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 250 insertions(+) create mode 100644 include/hotstuff/consensus.h (limited to 'include/hotstuff/consensus.h') diff --git a/include/hotstuff/consensus.h b/include/hotstuff/consensus.h new file mode 100644 index 0000000..18e891e --- /dev/null +++ b/include/hotstuff/consensus.h @@ -0,0 +1,250 @@ +#ifndef _HOTSTUFF_CONSENSUS_H +#define _HOTSTUFF_CONSENSUS_H + +#include +#include + +#include "hotstuff/promise.hpp" +#include "hotstuff/type.h" +#include "hotstuff/entity.h" +#include "hotstuff/crypto.h" + +namespace hotstuff { + +struct Proposal; +struct Vote; + +/** Abstraction for HotStuff protocol state machine (without network implementation). */ +class HotStuffCore { + block_t b0; /** the genesis block */ + /* === state variables === */ + /** block containing the QC for the highest block having one */ + block_t bqc; + block_t bexec; /**< last executed block */ + uint32_t vheight; /**< height of the block last voted for */ + /* === auxilliary variables === */ + privkey_bt priv_key; /**< private key for signing votes */ + std::set tails; /**< set of tail blocks */ + ReplicaConfig config; /**< replica configuration */ + /* === async event queues === */ + std::unordered_map qc_waiting; + promise_t propose_waiting; + + block_t sanity_check_delivered(const uint256_t &blk_hash); + void sanity_check_delivered(const block_t &blk); + void check_commit(const block_t &_bqc); + bool update(const uint256_t &bqc_hash); + void on_qc_finish(const block_t &blk); + void on_propose_(const block_t &blk); + + protected: + ReplicaID id; /**< identity of the replica itself */ + const int32_t parent_limit; /**< maximum number of parents */ + + public: + BoxObj storage; + + HotStuffCore(ReplicaID id, + privkey_bt &&priv_key, + int32_t parent_limit); + virtual ~HotStuffCore() = default; + + /* Inputs of the state machine triggered by external events, should called + * by the class user, with proper invariants. */ + + /** Call to initialize the protocol, should be called once before all other + * functions. */ + void on_init(uint32_t nfaulty) { config.nmajority = 2 * nfaulty + 1; } + + /** Call to deliver a block. + * A block is only delivered if itself is fetched, the block for the + * contained qc is fetched and all parents are delivered. The user should + * always ensure this invariant. The invalid blocks will be dropped by this + * function. + * @return true if valid */ + bool on_deliver_blk(const block_t &blk); + + /** Call upon the delivery of a proposal message. + * The block mentioned in the message should be already delivered. */ + void on_receive_proposal(const Proposal &prop); + + /** Call upon the delivery of a vote message. + * The block mentioned in the message should be already delivered. */ + void on_receive_vote(const Vote &vote); + + /** Call to submit new commands to be decided (executed). */ + void on_propose(const std::vector &cmds); + + /* Functions required to construct concrete instances for abstract classes. + * */ + + /* Outputs of the state machine triggering external events. The virtual + * functions should be implemented by the user to specify the behavior upon + * the events. */ + protected: + /** Called by HotStuffCore upon the decision being made for cmd. */ + virtual void do_decide(const command_t &cmd) = 0; + /** Called by HotStuffCore upon broadcasting a new proposal. + * The user should send the proposal message to all replicas except for + * itself. */ + virtual void do_broadcast_proposal(const Proposal &prop) = 0; + /** Called upon sending out a new vote to the next proposer. The user + * should send the vote message to a *good* proposer to have good liveness, + * while safety is always guaranteed by HotStuffCore. */ + virtual void do_vote(ReplicaID last_proposer, const Vote &vote) = 0; + + /* The user plugs in the detailed instances for those + * polymorphic data types. */ + public: + /** Create a partial certificate that proves the vote for a block. */ + virtual part_cert_bt create_part_cert(const PrivKey &priv_key, const uint256_t &blk_hash) = 0; + /** Create a partial certificate from its seralized form. */ + virtual part_cert_bt parse_part_cert(DataStream &s) = 0; + /** Create a quorum certificate that proves 2f+1 votes for a block. */ + virtual quorum_cert_bt create_quorum_cert(const uint256_t &blk_hash) = 0; + /** Create a quorum certificate from its serialized form. */ + virtual quorum_cert_bt parse_quorum_cert(DataStream &s) = 0; + /** Create a command object from its serialized form. */ + virtual command_t parse_cmd(DataStream &s) = 0; + + public: + /** Add a replica to the current configuration. This should only be called + * before running HotStuffCore protocol. */ + void add_replica(ReplicaID rid, const NetAddr &addr, pubkey_bt &&pub_key); + /** Try to prune blocks lower than last committed height - staleness. */ + void prune(uint32_t staleness); + + /* PaceMaker can use these functions to monitor the core protocol state + * transition */ + /** Get a promise resolved when the block gets a QC. */ + promise_t async_qc_finish(const block_t &blk); + /** Get a promise resolved when a new block is proposed. */ + promise_t async_wait_propose(); + + /* Other useful functions */ + block_t get_genesis() { return b0; } + const ReplicaConfig &get_config() { return config; } + int8_t get_cmd_decision(const uint256_t &cmd_hash); + ReplicaID get_id() { return id; } + operator std::string () const; +}; + +/** Abstraction for proposal messages. */ +struct Proposal: public Serializable { + ReplicaID proposer; + /** hash for the block containing the highest QC */ + uint256_t bqc_hash; + /** block being proposed */ + block_t blk; + + /** handle of the core object to allow polymorphism. The user should use + * a pointer to the object of the class derived from HotStuffCore */ + HotStuffCore *hsc; + + Proposal(HotStuffCore *hsc): blk(nullptr), hsc(hsc) {} + Proposal(ReplicaID proposer, + const uint256_t &bqc_hash, + block_t &blk, + HotStuffCore *hsc): + proposer(proposer), + bqc_hash(bqc_hash), + blk(blk), hsc(hsc) {} + + void serialize(DataStream &s) const override { + s << proposer + << bqc_hash + << *blk; + } + + void unserialize(DataStream &s) override { + assert(hsc != nullptr); + s >> proposer + >> bqc_hash; + Block _blk; + _blk.unserialize(s, hsc); + blk = hsc->storage->add_blk(std::move(_blk)); + } + + operator std::string () const { + DataStream s; + s << ""; + return std::string(std::move(s)); + } +}; + +/** Abstraction for vote messages. */ +struct Vote: public Serializable { + ReplicaID voter; + /** hash for the block containing the highest QC */ + uint256_t bqc_hash; + /** block being voted */ + uint256_t blk_hash; + /** proof of validity for the vote (nullptr for a negative vote) */ + part_cert_bt cert; + + /** handle of the core object to allow polymorphism */ + HotStuffCore *hsc; + + Vote(HotStuffCore *hsc): cert(nullptr), hsc(hsc) {} + Vote(ReplicaID voter, + const uint256_t &bqc_hash, + const uint256_t &blk_hash, + part_cert_bt &&cert, + HotStuffCore *hsc): + voter(voter), + bqc_hash(bqc_hash), + blk_hash(blk_hash), + cert(std::move(cert)), hsc(hsc) {} + + Vote(const Vote &other): + voter(other.voter), + bqc_hash(other.bqc_hash), + blk_hash(other.blk_hash), + cert(other.cert->clone()), + hsc(other.hsc) {} + + Vote(Vote &&other) = default; + + void serialize(DataStream &s) const override { + s << voter + << bqc_hash + << blk_hash; + if (cert == nullptr) + s << (uint8_t)0; + else + s << (uint8_t)1 << *cert; + } + + void unserialize(DataStream &s) override { + assert(hsc != nullptr); + uint8_t has_cert; + s >> voter + >> bqc_hash + >> blk_hash + >> has_cert; + cert = has_cert ? hsc->parse_part_cert(s) : nullptr; + } + + bool verify() const { + assert(hsc != nullptr); + return cert->verify(hsc->get_config().get_pubkey(voter)) && + cert->get_blk_hash() == blk_hash; + } + + operator std::string () const { + DataStream s; + s << ""; + return std::string(std::move(s)); + } +}; + +} + +#endif -- cgit v1.2.3-70-g09d2