init

15 files changed, 3636 insertions, 0 deletions

diff --git a/src/client.cpp b/src/client.cpp
new file mode 100644
index 0000000..f787003
--- /dev/null
+++ b/src/client.cpp
@@ -0,0 +1,43 @@
+#include "client.h"
+
+namespace hotstuff {
+
+uint64_t CommandDummy::cnt = 0;
+
+void MsgClient::gen_reqcmd(const Command &cmd) {
+    DataStream s;
+    set_opcode(REQ_CMD);
+    s << cmd;
+    set_payload(std::move(s));
+}
+
+void MsgClient::parse_reqcmd(CommandDummy &cmd) const {
+    DataStream s(get_payload());
+    s >> cmd;
+}
+
+void MsgClient::gen_respcmd(const uint256_t &cmd_hash, const Finality &fin) {
+    DataStream s;
+    set_opcode(RESP_CMD);
+    s << cmd_hash << fin;
+    set_payload(std::move(s));
+}
+
+void MsgClient::parse_respcmd(uint256_t &cmd_hash, Finality &fin) const {
+    DataStream s(get_payload());
+    s >> cmd_hash >> fin;
+}
+
+void MsgClient::gen_chkcmd(const uint256_t &cmd_hash) {
+    DataStream s;
+    set_opcode(CHK_CMD);
+    s << cmd_hash;
+    set_payload(std::move(s));
+}
+
+void MsgClient::parse_chkcmd(uint256_t &cmd_hash) const {
+    DataStream s(get_payload());
+    s >> cmd_hash;
+}
+
+}
diff --git a/src/client.h b/src/client.h
new file mode 100644
index 0000000..dd1cfee
--- /dev/null
+++ b/src/client.h
@@ -0,0 +1,66 @@
+#ifndef _HOTSTUFF_CLIENT_H
+#define _HOTSTUFF_CLIENT_H
+
+#include "type.h"
+#include "salticidae/msg.h"
+#include "entity.h"
+
+namespace hotstuff {
+
+enum {
+    REQ_CMD = 0x4,
+    RESP_CMD = 0x5,
+    CHK_CMD = 0x6
+};
+
+class CommandDummy: public Command {
+    static uint64_t cnt;
+    uint64_t n;
+    uint256_t hash;
+
+    public:
+
+    CommandDummy() {}
+
+    ~CommandDummy() override {}
+
+    CommandDummy(uint64_t n):
+        n(n), hash(salticidae::get_hash(*this)) {}
+
+    static command_t make_cmd() {
+        return new CommandDummy(cnt++);
+    }
+
+    void serialize(DataStream &s) const override {
+        s << n;
+    }
+
+    void unserialize(DataStream &s) override {
+        s >> n;
+        hash = salticidae::get_hash(*this);
+    }
+
+    const uint256_t &get_hash() const override {
+        return hash;
+    }
+
+    bool verify() const override {
+        return true;
+    }
+};
+
+struct MsgClient: public salticidae::MsgBase<> {
+    using MsgBase::MsgBase;
+    void gen_reqcmd(const Command &cmd);
+    void parse_reqcmd(CommandDummy &cmd) const;
+
+    void gen_respcmd(const uint256_t &cmd_hash, const Finality &fin);
+    void parse_respcmd(uint256_t &cmd_hash, Finality &fin) const;
+
+    void gen_chkcmd(const uint256_t &cmd_hash);
+    void parse_chkcmd(uint256_t &cmd_hash) const;
+};
+
+}
+
+#endif
diff --git a/src/core.cpp b/src/core.cpp
new file mode 100644
index 0000000..d6a4cc7
--- /dev/null
+++ b/src/core.cpp
@@ -0,0 +1,723 @@
+#include <stack>
+#include "core.h"
+
+using salticidae::DataStream;
+using salticidae::static_pointer_cast;
+using salticidae::get_hash;
+
+#define LOG_INFO HOTSTUFF_LOG_INFO
+#define LOG_DEBUG HOTSTUFF_LOG_DEBUG
+#define LOG_WARN HOTSTUFF_LOG_WARN
+
+namespace hotstuff {
+
+void MsgHotStuff::gen_propose(const Proposal &proposal) {
+    DataStream s;
+    set_opcode(PROPOSE);
+    s << proposal;
+    set_payload(std::move(s));
+}
+
+void MsgHotStuff::parse_propose(Proposal &proposal) const {
+    DataStream(get_payload()) >> proposal;
+}
+
+void MsgHotStuff::gen_vote(const Vote &vote) {
+    DataStream s;
+    set_opcode(VOTE);
+    s << vote;
+    set_payload(std::move(s));
+}
+
+void MsgHotStuff::parse_vote(Vote &vote) const {
+    DataStream(get_payload()) >> vote;
+}
+
+void MsgHotStuff::gen_qfetchblk(const std::vector<uint256_t> &blk_hashes) {
+    DataStream s;
+    set_opcode(QUERY_FETCH_BLK);
+    gen_hash_list(s, blk_hashes);
+    set_payload(std::move(s));
+}
+
+void MsgHotStuff::parse_qfetchblk(std::vector<uint256_t> &blk_hashes) const {
+    DataStream s(get_payload());
+    parse_hash_list(s, blk_hashes);
+}
+
+void MsgHotStuff::gen_rfetchblk(const std::vector<block_t> &blks) {
+    DataStream s;
+    set_opcode(RESP_FETCH_BLK);
+    s << htole((uint32_t)blks.size());
+    for (auto blk: blks) s << *blk;
+    set_payload(std::move(s));
+}
+
+void MsgHotStuff::parse_rfetchblk(std::vector<block_t> &blks, HotStuffCore *hsc) const {
+    DataStream s;
+    uint32_t size;
+    s >> size;
+    size = letoh(size);
+    blks.resize(size);
+    for (auto &blk: blks)
+    {
+        Block _blk;
+        _blk.unserialize(s, hsc);
+        if (!_blk.verify(hsc->get_config()))
+            blk = hsc->storage->add_blk(std::move(_blk));
+        else
+        {
+            blk = nullptr;
+            LOG_WARN("block is invalid");
+        }
+    }
+}
+
+/* The core logic of HotStuff, is farily simple :) */
+/*** begin HotStuff protocol logic ***/
+HotStuffCore::HotStuffCore(ReplicaID id,
+                            privkey_bt &&priv_key,
+                            int32_t parent_limit):
+        b0(new Block(true, 1)),
+        bqc(b0),
+        bexec(b0),
+        vheight(0),
+        priv_key(std::move(priv_key)),
+        tails{bqc},
+        id(id),
+        parent_limit(parent_limit),
+        storage(new EntityStorage()) {
+    storage->add_blk(b0);
+    b0->qc_ref = b0;
+}
+
+void HotStuffCore::sanity_check_delivered(const block_t &blk) {
+    if (!blk->delivered)
+        throw std::runtime_error("block not delivered");
+}
+
+block_t HotStuffCore::sanity_check_delivered(const uint256_t &blk_hash) {
+    block_t blk = storage->find_blk(blk_hash);
+    if (blk == nullptr || !blk->delivered)
+        throw std::runtime_error("block not delivered");
+    return std::move(blk);
+}
+
+bool HotStuffCore::on_deliver_blk(const block_t &blk) {
+    if (blk->delivered)
+    {
+        LOG_WARN("attempt to deliver a block twice");
+        return false;
+    }
+    blk->parents.clear();
+    for (const auto &hash: blk->parent_hashes)
+    {
+        block_t p = sanity_check_delivered(hash);
+        blk->parents.push_back(p);
+    }
+    blk->height = blk->parents[0]->height + 1;
+    for (const auto &cmd: blk->cmds)
+        cmd->container = blk;
+
+    if (blk->qc)
+    {
+        block_t _blk = storage->find_blk(blk->qc->get_blk_hash());
+        if (_blk == nullptr)
+            throw std::runtime_error("block referred by qc not fetched");
+        blk->qc_ref = std::move(_blk);
+    } // otherwise blk->qc_ref remains null
+
+    for (auto pblk: blk->parents) tails.erase(pblk);
+    tails.insert(blk);
+
+    blk->delivered = true;
+    LOG_DEBUG("delivered %.10s", get_hex(blk->get_hash()).c_str());
+    return true;
+}
+
+void HotStuffCore::check_commit(const block_t &_blk) {
+    const block_t &blk = _blk->qc_ref;
+    if (blk->qc_ref == nullptr) return;
+    if (blk->decision) return;
+    block_t p = blk->parents[0];
+    if (p == blk->qc_ref)
+    { /* commit */
+        std::vector<block_t> commit_queue;
+        block_t b;
+        for (b = p; b->height > bexec->height; b = b->parents[0])
+        { /* todo: also commit the uncles/aunts */
+            commit_queue.push_back(b);
+        }
+        if (b != bexec)
+            throw std::runtime_error("safety breached :(");
+        for (auto it = commit_queue.rbegin(); it != commit_queue.rend(); it++)
+        {
+            const block_t &blk = *it;
+            blk->decision = 1;
+#ifdef HOTSTUFF_ENABLE_LOG_PROTO
+            LOG_INFO("commit blk %.10s", get_hex10(blk->get_hash()).c_str());
+#endif
+            for (auto cmd: blk->cmds)
+                do_decide(cmd);
+        }
+        bexec = p;
+    }
+}
+
+bool HotStuffCore::update(const uint256_t &bqc_hash) {
+    block_t _bqc = sanity_check_delivered(bqc_hash);
+    if (_bqc->qc_ref == nullptr) return false;
+    check_commit(_bqc);
+    if (_bqc->qc_ref->height > bqc->qc_ref->height)
+        bqc = _bqc;
+    return true;
+}
+
+void HotStuffCore::on_propose(const std::vector<command_t> &cmds) {
+    size_t nparents = parent_limit < 1 ? tails.size() : parent_limit;
+    assert(tails.size() > 0);
+    block_t p = *tails.rbegin();
+    std::vector<block_t> parents{p};
+    tails.erase(p);
+    nparents--;
+    /* add the rest of tails as "uncles/aunts" */
+    while (nparents--)
+    {
+        auto it = tails.begin();
+        parents.push_back(*it);
+        tails.erase(it);
+    }
+    quorum_cert_bt qc = nullptr;
+    block_t qc_ref = nullptr;
+    if (p != b0 && p->voted.size() >= config.nmajority)
+    {
+        qc = p->self_qc->clone();
+        qc->compute();
+        qc_ref = p;
+    }
+    /* create a new block */
+    block_t bnew = storage->add_blk(
+        Block(
+            parents,
+            cmds,
+            p->height + 1,
+            std::move(qc), qc_ref,
+            nullptr
+        ));
+    const uint256_t bnew_hash = bnew->get_hash();
+    bnew->self_qc = create_quorum_cert(bnew_hash);
+    on_deliver_blk(bnew);
+    update(bnew_hash);
+    Proposal prop(id, bqc->get_hash(), bnew, nullptr);
+#ifdef HOTSTUFF_ENABLE_LOG_PROTO
+    LOG_INFO("propose %s", std::string(*bnew).c_str());
+#endif
+    /* self-vote */
+    on_receive_vote(
+        Vote(id, bqc->get_hash(), bnew_hash,
+            create_part_cert(*priv_key, bnew_hash), this));
+    on_propose_(bnew);
+    /* boradcast to other replicas */
+    do_broadcast_proposal(prop);
+}
+
+void HotStuffCore::on_receive_proposal(const Proposal &prop) {
+    if (!update(prop.bqc_hash)) return;
+#ifdef HOTSTUFF_ENABLE_LOG_PROTO
+    LOG_INFO("got %s", std::string(prop).c_str());
+#endif
+    block_t bnew = prop.blk;
+    sanity_check_delivered(bnew);
+    bool opinion = false;
+    if (bnew->height > vheight)
+    {
+        block_t pref = bqc->qc_ref;
+        block_t b;
+        for (b = bnew;
+            b->height > pref->height;
+            b = b->parents[0]);
+        opinion = b == pref;
+        vheight = bnew->height;
+    }
+#ifdef HOTSTUFF_ENABLE_LOG_PROTO
+    LOG_INFO("now state: %s", std::string(*this).c_str());
+#endif
+    do_vote(prop.proposer,
+        Vote(id,
+            bqc->get_hash(),
+            bnew->get_hash(),
+            (opinion ?
+                create_part_cert(*priv_key, bnew->get_hash()) :
+                nullptr),
+            nullptr));
+}
+
+void HotStuffCore::on_receive_vote(const Vote &vote) {
+    if (!update(vote.bqc_hash)) return;
+#ifdef HOTSTUFF_ENABLE_LOG_PROTO
+    LOG_INFO("got %s", std::string(vote).c_str());
+    LOG_INFO("now state: %s", std::string(*this).c_str());
+#endif
+
+    block_t blk = sanity_check_delivered(vote.blk_hash);
+    if (vote.cert == nullptr) return;
+    if (!vote.verify())
+    {
+        LOG_WARN("invalid vote");
+        return;
+    }
+    if (!blk->voted.insert(vote.voter).second)
+    {
+        LOG_WARN("duplicate votes");
+        return;
+    }
+    size_t qsize = blk->voted.size();
+    if (qsize <= config.nmajority)
+    {
+        blk->self_qc->add_part(vote.voter, *vote.cert);
+        if (qsize == config.nmajority)
+            on_qc_finish(blk);
+    }
+}
+/*** end HotStuff protocol logic ***/
+
+void HotStuffCore::prune(uint32_t staleness) {
+    block_t start;
+    /* skip the blocks */
+    for (start = bexec; staleness; staleness--, start = start->parents[0])
+        if (!start->parents.size()) return;
+    std::stack<block_t> s;
+    start->qc_ref = nullptr;
+    s.push(start);
+    while (!s.empty())
+    {
+        auto &blk = s.top();
+        if (blk->parents.empty())
+        {
+            storage->try_release_blk(blk);
+            s.pop();
+            continue;
+        }
+        blk->qc_ref = nullptr;
+        s.push(blk->parents.back());
+        blk->parents.pop_back();
+    }
+}
+
+int8_t HotStuffCore::get_cmd_decision(const uint256_t &cmd_hash) {
+    auto cmd = storage->find_cmd(cmd_hash);
+    return cmd != nullptr ? cmd->get_decision() : 0;
+}
+
+void HotStuffCore::add_replica(ReplicaID rid, const NetAddr &addr,
+                                pubkey_bt &&pub_key) {
+    config.add_replica(rid, 
+            ReplicaInfo(rid, addr, std::move(pub_key)));
+    b0->voted.insert(rid);
+}
+
+promise_t HotStuffCore::async_qc_finish(const block_t &blk) {
+    if (blk->voted.size() >= config.nmajority)
+        return promise_t([](promise_t &pm) {
+            pm.resolve();
+        });
+    auto it = qc_waiting.find(blk);
+    if (it == qc_waiting.end())
+        it = qc_waiting.insert(std::make_pair(blk, promise_t())).first;
+    return it->second;
+}
+
+void HotStuffCore::on_qc_finish(const block_t &blk) {
+    auto it = qc_waiting.find(blk);
+    if (it != qc_waiting.end())
+    {
+        it->second.resolve();
+        qc_waiting.erase(it);
+    }
+}
+
+promise_t HotStuffCore::async_wait_propose() {
+    return propose_waiting;
+}
+
+void HotStuffCore::on_propose_(const block_t &blk) {
+    auto t = std::move(propose_waiting);
+    propose_waiting = promise_t();
+    t.resolve(blk);
+}
+
+HotStuffCore::operator std::string () const {
+    DataStream s;
+    s << "<hotstuff "
+      << "bqc=" << get_hex10(bqc->get_hash()) << " "
+      << "bexec=" << get_hex10(bqc->get_hash()) << " "
+      << "vheight=" << std::to_string(vheight) << " "
+      << "tails=" << std::to_string(tails.size()) << ">";
+    return std::string(std::move(s));
+}
+
+void HotStuffBase::add_replica(ReplicaID idx, const NetAddr &addr,
+                                pubkey_bt &&pub_key) {
+    HotStuffCore::add_replica(idx, addr, std::move(pub_key));
+    if (addr != listen_addr)
+        pn.add_peer(addr);
+}
+
+void HotStuffBase::on_fetch_blk(const block_t &blk) {
+#ifdef HOTSTUFF_ENABLE_TX_PROFILE
+    blk_profiler.get_tx(blk->get_hash());
+#endif
+    LOG_DEBUG("fetched %.10s", get_hex(blk->get_hash()).c_str());
+    part_fetched++;
+    fetched++;
+    for (auto cmd: blk->get_cmds()) on_fetch_cmd(cmd);
+    const uint256_t &blk_hash = blk->get_hash();
+    auto it = blk_fetch_waiting.find(blk_hash);
+    if (it != blk_fetch_waiting.end())
+    {
+        it->second.resolve(blk);
+        blk_fetch_waiting.erase(it);
+    }
+}
+
+void HotStuffBase::on_fetch_cmd(const command_t &cmd) {
+    const uint256_t &cmd_hash = cmd->get_hash();
+    auto it = cmd_fetch_waiting.find(cmd_hash);
+    if (it != cmd_fetch_waiting.end())
+    {
+        it->second.resolve(cmd);
+        cmd_fetch_waiting.erase(it);
+    }
+}
+
+void HotStuffBase::on_deliver_blk(const block_t &blk) {
+    const uint256_t &blk_hash = blk->get_hash();
+    bool valid;
+    /* sanity check: all parents must be delivered */
+    for (const auto &p: blk->get_parent_hashes())
+        assert(storage->is_blk_delivered(p));
+    if ((valid = HotStuffCore::on_deliver_blk(blk)))
+    {
+        LOG_DEBUG("block %.10s delivered",
+                get_hex(blk_hash).c_str());
+        part_parent_size += blk->get_parent_hashes().size();
+        part_delivered++;
+        delivered++;
+    }
+    else
+    {
+        LOG_WARN("dropping invalid block");
+    }
+
+    auto it = blk_delivery_waiting.find(blk_hash);
+    if (it != blk_delivery_waiting.end())
+    {
+        auto &pm = it->second;
+        if (valid)
+        {
+            pm.elapsed.stop(false);
+            auto sec = pm.elapsed.elapsed_sec;
+            part_delivery_time += sec;
+            part_delivery_time_min = std::min(part_delivery_time_min, sec);
+            part_delivery_time_max = std::max(part_delivery_time_max, sec);
+
+            pm.resolve(blk);
+        }
+        else
+        {
+            pm.reject(blk);
+            // TODO: do we need to also free it from storage?
+        }
+        blk_delivery_waiting.erase(it);
+    }
+}
+
+promise_t HotStuffBase::async_fetch_blk(const uint256_t &blk_hash,
+                                        const NetAddr *replica_id,
+                                        bool fetch_now) {
+    if (storage->is_blk_fetched(blk_hash))
+        return promise_t([this, &blk_hash](promise_t pm){
+            pm.resolve(storage->find_blk(blk_hash));
+        });
+    auto it = blk_fetch_waiting.find(blk_hash);
+    if (it == blk_fetch_waiting.end())
+    {
+#ifdef HOTSTUFF_ENABLE_TX_PROFILE
+        blk_profiler.rec_tx(blk_hash, false);
+#endif
+        it = blk_fetch_waiting.insert(
+            std::make_pair(
+                blk_hash,
+                BlockFetchContext(blk_hash, this))).first;
+    }
+    if (replica_id != nullptr)
+        it->second.add_replica(*replica_id, fetch_now);
+    return static_cast<promise_t &>(it->second);
+}
+
+promise_t HotStuffBase::async_fetch_cmd(const uint256_t &cmd_hash,
+                                    const NetAddr *replica_id,
+                                    bool fetch_now) {
+    if (storage->is_cmd_fetched(cmd_hash))
+        return promise_t([this, &cmd_hash](promise_t pm){
+            pm.resolve(storage->find_cmd(cmd_hash));
+        });
+    auto it = cmd_fetch_waiting.find(cmd_hash);
+    if (it == cmd_fetch_waiting.end())
+    {
+        it = cmd_fetch_waiting.insert(
+            std::make_pair(cmd_hash, CmdFetchContext(cmd_hash, this))).first;
+    }
+    if (replica_id != nullptr)
+        it->second.add_replica(*replica_id, fetch_now);
+    return static_cast<promise_t &>(it->second);
+}
+
+promise_t HotStuffBase::async_deliver_blk(const uint256_t &blk_hash,
+                                        const NetAddr &replica_id) {
+    if (storage->is_blk_delivered(blk_hash))
+        return promise_t([this, &blk_hash](promise_t pm) {
+            pm.resolve(storage->find_blk(blk_hash));
+        });
+    auto it = blk_delivery_waiting.find(blk_hash);
+    if (it != blk_delivery_waiting.end())
+        return static_cast<promise_t &>(it->second);
+    BlockDeliveryContext pm{[](promise_t){}};
+    it = blk_delivery_waiting.insert(std::make_pair(blk_hash, pm)).first;
+    /* otherwise the on_deliver_batch will resolve */
+    async_fetch_blk(blk_hash, &replica_id).then([this, replica_id](block_t blk) {
+        /* qc_ref should be fetched */
+        std::vector<promise_t> pms;
+        const auto &qc = blk->get_qc();
+        if (qc)
+            pms.push_back(async_fetch_blk(qc->get_blk_hash(), &replica_id));
+        /* the parents should be delivered */
+        for (const auto &phash: blk->get_parent_hashes())
+            pms.push_back(async_deliver_blk(phash, replica_id));
+        promise::all(pms).then([this, blk]() {
+            on_deliver_blk(blk);
+        });
+    });
+    return static_cast<promise_t &>(pm);
+}
+
+void HotStuffBase::propose_handler(const MsgHotStuff &msg, conn_t conn_) {
+    auto conn = static_pointer_cast<PeerNetwork<MsgHotStuff>::Conn>(conn_);
+    const NetAddr &peer = conn->get_peer();
+    Proposal prop(this);
+    msg.parse_propose(prop);
+    block_t blk = prop.blk;
+    promise::all(std::vector<promise_t>{
+        async_deliver_blk(prop.bqc_hash, peer),
+        async_deliver_blk(blk->get_hash(), peer),
+    }).then([this, prop = std::move(prop)]() {
+        on_receive_proposal(prop);
+    });
+}
+
+void HotStuffBase::vote_handler(const MsgHotStuff &msg, conn_t conn_) {
+    auto conn = static_pointer_cast<PeerNetwork<MsgHotStuff>::Conn>(conn_);
+    const NetAddr &peer = conn->get_peer();
+    Vote vote(this);
+    msg.parse_vote(vote);
+    promise::all(std::vector<promise_t>{
+        async_deliver_blk(vote.bqc_hash, peer),
+        async_deliver_blk(vote.blk_hash, peer)
+    }).then([this, vote = std::move(vote)]() {
+        on_receive_vote(vote);
+    });
+}
+
+void HotStuffBase::query_fetch_blk_handler(const MsgHotStuff &msg, conn_t conn_) {
+    auto conn = static_pointer_cast<PeerNetwork<MsgHotStuff>::Conn>(conn_);
+    const NetAddr replica = conn->get_peer();
+    std::vector<uint256_t> blk_hashes;
+    msg.parse_qfetchblk(blk_hashes);
+
+    std::vector<promise_t> pms;
+    for (const auto &h: blk_hashes)
+        pms.push_back(async_fetch_blk(h, nullptr));
+    promise::all(pms).then([replica, this](const promise::values_t values) {
+        MsgHotStuff resp;
+        std::vector<block_t> blks;
+        for (auto &v: values)
+        {
+            auto blk = promise::any_cast<block_t>(v);
+            blks.push_back(blk);
+        }
+        resp.gen_rfetchblk(blks);
+        pn.send_msg(resp, replica);
+    });
+}
+
+void HotStuffBase::resp_fetch_blk_handler(const MsgHotStuff &msg, conn_t) {
+    std::vector<block_t> blks;
+    msg.parse_rfetchblk(blks, this);
+    for (const auto &blk: blks)
+        if (blk) on_fetch_blk(blk);
+}
+
+void HotStuffBase::print_stat() const {
+    LOG_INFO("===== begin stats =====");
+    LOG_INFO("-------- queues -------");
+    LOG_INFO("blk_fetch_waiting: %lu", blk_fetch_waiting.size());
+    LOG_INFO("blk_delivery_waiting: %lu", blk_delivery_waiting.size());
+    LOG_INFO("cmd_fetch_waiting: %lu", cmd_fetch_waiting.size());
+    LOG_INFO("decision_waiting: %lu", decision_waiting.size());
+    LOG_INFO("-------- misc ---------");
+    LOG_INFO("fetched: %lu", fetched);
+    LOG_INFO("delivered: %lu", delivered);
+    LOG_INFO("cmd_cache: %lu", storage->get_cmd_cache_size());
+    LOG_INFO("blk_cache: %lu", storage->get_blk_cache_size());
+    LOG_INFO("------ misc (10s) -----");
+    LOG_INFO("fetched: %lu", part_fetched);
+    LOG_INFO("delivered: %lu", part_delivered);
+    LOG_INFO("decided: %lu", part_decided);
+    LOG_INFO("gened: %lu", part_gened);
+    LOG_INFO("avg. parent_size: %.3f",
+            part_delivered ? part_parent_size / double(part_delivered) : 0);
+    LOG_INFO("delivery time: %.3f avg, %.3f min, %.3f max",
+            part_delivered ? part_delivery_time / double(part_delivered) : 0,
+            part_delivery_time_min == double_inf ? 0 : part_delivery_time_min,
+            part_delivery_time_max);
+
+    part_parent_size = 0;
+    part_fetched = 0;
+    part_delivered = 0;
+    part_decided = 0;
+    part_gened = 0;
+    part_delivery_time = 0;
+    part_delivery_time_min = double_inf;
+    part_delivery_time_max = 0;
+    LOG_INFO("-- sent opcode (10s) --");
+    auto &sent_op = pn.get_sent_by_opcode();
+    for (auto &op: sent_op)
+    {
+        auto &val = op.second;
+        LOG_INFO("%02x: %lu, %.2fBpm", op.first,
+                val.first, val.first ? val.second / double(val.first) : 0);
+        val.first = val.second = 0;
+    }
+    LOG_INFO("-- recv opcode (10s) --");
+    auto &recv_op = pn.get_recv_by_opcode();
+    for (auto &op: recv_op)
+    {
+        auto &val = op.second;
+        LOG_INFO("%02x: %lu, %.2fBpm", op.first,
+                val.first, val.first ? val.second / double(val.first) : 0);
+        val.first = val.second = 0;
+    }
+    LOG_INFO("--- replica msg. (10s) ---");
+    size_t _nsent = 0;
+    size_t _nrecv = 0;
+    for (const auto &replica: pn.all_peers())
+    {
+        auto conn = pn.get_peer_conn(replica);
+        size_t ns = conn->get_nsent();
+        size_t nr = conn->get_nrecv();
+        conn->clear_nsent();
+        conn->clear_nrecv();
+        LOG_INFO("%s: %u, %u, %u",
+            std::string(replica).c_str(), ns, nr, part_fetched_replica[replica]);
+        _nsent += ns;
+        _nrecv += nr;
+        part_fetched_replica[replica] = 0;
+    }
+    nsent += _nsent;
+    nrecv += _nrecv;
+    LOG_INFO("sent: %lu", _nsent);
+    LOG_INFO("recv: %lu", _nrecv);
+    LOG_INFO("--- replica msg. total ---");
+    LOG_INFO("sent: %lu", nsent);
+    LOG_INFO("recv: %lu", nrecv);
+    LOG_INFO("====== end stats ======");
+}
+
+promise_t HotStuffBase::async_decide(const uint256_t &cmd_hash) {
+    if (get_cmd_decision(cmd_hash))
+        return promise_t([this, cmd_hash](promise_t pm){
+            pm.resolve(storage->find_cmd(cmd_hash));
+        });
+    /* otherwise the do_decide will resolve the promise */
+    auto it = decision_waiting.find(cmd_hash);
+    if (it == decision_waiting.end())
+    {
+        promise_t pm{[](promise_t){}};
+        it = decision_waiting.insert(std::make_pair(cmd_hash, pm)).first;
+    }
+    return it->second;
+}
+
+HotStuffBase::HotStuffBase(uint32_t blk_size,
+                    int32_t parent_limit,
+                    ReplicaID rid,
+                    privkey_bt &&priv_key,
+                    NetAddr listen_addr,
+                    EventContext eb,
+                    pacemaker_bt pmaker):
+        HotStuffCore(rid, std::move(priv_key), parent_limit),
+        listen_addr(listen_addr),
+        blk_size(blk_size),
+        eb(eb),
+        pmaker(std::move(pmaker)),
+        pn(eb),
+
+        fetched(0), delivered(0),
+        nsent(0), nrecv(0),
+        part_parent_size(0),
+        part_fetched(0),
+        part_delivered(0),
+        part_decided(0),
+        part_gened(0),
+        part_delivery_time(0),
+        part_delivery_time_min(double_inf),
+        part_delivery_time_max(0)
+{
+    if (pmaker == nullptr)
+        this->pmaker = new PaceMakerDummy(this);
+    /* register the handlers for msg from replicas */
+    pn.reg_handler(PROPOSE, std::bind(&HotStuffBase::propose_handler, this, _1, _2));
+    pn.reg_handler(VOTE, std::bind(&HotStuffBase::vote_handler, this, _1, _2));
+    pn.reg_handler(QUERY_FETCH_BLK, std::bind(&HotStuffBase::query_fetch_blk_handler, this, _1, _2));
+    pn.reg_handler(RESP_FETCH_BLK, std::bind(&HotStuffBase::resp_fetch_blk_handler, this, _1, _2));
+    pn.init(listen_addr);
+}
+
+void HotStuffBase::do_broadcast_proposal(const Proposal &prop) {
+    MsgHotStuff prop_msg;
+    prop_msg.gen_propose(prop);
+    for (const auto &replica: pn.all_peers())
+        pn.send_msg(prop_msg, replica);
+}
+
+void HotStuffBase::do_vote(ReplicaID last_proposer, const Vote &vote) {
+    MsgHotStuff vote_msg;
+    vote_msg.gen_vote(vote);
+    pmaker->next_proposer(last_proposer)
+            .then([this, vote_msg](ReplicaID proposer) {
+        pn.send_msg(vote_msg, get_config().get_addr(proposer));
+    });
+}
+
+void HotStuffBase::do_decide(const command_t &cmd) {
+    auto it = decision_waiting.find(cmd->get_hash());
+    if (it != decision_waiting.end())
+    {
+        it->second.resolve(cmd);
+        decision_waiting.erase(it);
+    }
+}
+
+HotStuffBase::~HotStuffBase() {}
+
+void HotStuffBase::start(bool eb_loop) {
+    /* ((n - 1) + 1 - 1) / 3 */
+    uint32_t nfaulty = pn.all_peers().size() / 3;
+    if (nfaulty == 0)
+        LOG_WARN("too few replicas in the system to tolerate any failure");
+    on_init(nfaulty);
+    if (eb_loop)
+        eb.dispatch();
+}
+
+}
diff --git a/src/core.h b/src/core.h
new file mode 100644
index 0000000..c7e1fe6
--- /dev/null
+++ b/src/core.h
@@ -0,0 +1,631 @@
+#ifndef _HOTSTUFF_CORE_H
+#define _HOTSTUFF_CORE_H
+
+#include <queue>
+#include <set>
+#include <unordered_map>
+#include <unordered_set>
+
+#include "salticidae/stream.h"
+#include "salticidae/util.h"
+#include "salticidae/network.h"
+#include "salticidae/msg.h"
+
+#include "promise.hpp"
+#include "util.h"
+#include "entity.h"
+#include "crypto.h"
+
+using salticidae::EventContext;
+using salticidae::Event;
+using salticidae::NetAddr;
+using salticidae::MsgNetwork;
+using salticidae::PeerNetwork;
+using salticidae::ElapsedTime;
+using salticidae::_1;
+using salticidae::_2;
+
+namespace hotstuff {
+
+const double ent_waiting_timeout = 10;
+const double double_inf = 1e10;
+
+enum {
+    PROPOSE = 0x0,
+    VOTE = 0x1,
+    QUERY_FETCH_BLK = 0x2,
+    RESP_FETCH_BLK = 0x3,
+};
+
+using promise::promise_t;
+
+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