aboutsummaryrefslogtreecommitdiff
path: root/include/hotstuff/consensus.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/hotstuff/consensus.h')
-rw-r--r--include/hotstuff/consensus.h250
1 files changed, 250 insertions, 0 deletions
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 <set>
+#include <unordered_map>
+
+#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<block_t, BlockHeightCmp> tails; /**< set of tail blocks */
+ ReplicaConfig config; /**< replica configuration */
+ /* === async event queues === */
+ std::unordered_map<block_t, promise_t> 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<EntityStorage> 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<command_t> &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 << "<proposal "
+ << "rid=" << std::to_string(proposer) << " "
+ << "bqc=" << get_hex10(bqc_hash) << " "
+ << "blk=" << get_hex10(blk->get_hash()) << ">";
+ 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 << "<vote "
+ << "rid=" << std::to_string(voter) << " "
+ << "bqc=" << get_hex10(bqc_hash) << " "
+ << "blk=" << get_hex10(blk_hash) << " "
+ << "cert=" << (cert ? "yes" : "no") << ">";
+ return std::string(std::move(s));
+ }
+};
+
+}
+
+#endif