From 0f341fe7f092f704e1c1952c72085eb1ebd2086a Mon Sep 17 00:00:00 2001
From: Determinant <ted.sybil@gmail.com>
Date: Wed, 14 Nov 2018 15:19:32 -0500
Subject: use ThreadCall pattern

---
 include/salticidae/conn.h    | 267 +++++++++++++------------------------------
 include/salticidae/event.h   |  86 ++++++++++++++
 include/salticidae/network.h | 217 +++++++++++++++--------------------
 include/salticidae/queue.h   |   2 +-
 4 files changed, 258 insertions(+), 314 deletions(-)

(limited to 'include')

diff --git a/include/salticidae/conn.h b/include/salticidae/conn.h
index a86a4d2..2ef6b50 100644
--- a/include/salticidae/conn.h
+++ b/include/salticidae/conn.h
@@ -95,6 +95,8 @@ class ConnPool {
         void send_data(int, int);
         void conn_server(int, int);
 
+        /** Stop the worker and I/O events. */
+        void stop();
         /** Terminate the connection. */
         void terminate();
 
@@ -146,54 +148,27 @@ class ConnPool {
     const size_t seg_buff_size;
 
     /* owned by user loop */
-    int mlisten_fd[2]; /**< for connection events sent to the user loop */
-    Event ev_mlisten;
+    BoxObj<ThreadCall> user_tcall;
     conn_callback_t conn_cb; 
 
     /* owned by the dispatcher */
+    Event ev_listen;
     std::unordered_map<int, conn_t> pool;
     int listen_fd;  /**< for accepting new network connections */
-    Event ev_listen;
-    Event ev_dlisten;
-    std::mutex cp_mlock;
 
     void update_conn(const conn_t &conn, bool connected) {
-        auto dcmd = new UserConn(conn, connected);
-        write(mlisten_fd[1], &dcmd, sizeof(dcmd));
+        user_tcall->call([this, conn, connected](ThreadCall::Handle &) {
+            if (conn_cb) conn_cb(*conn, connected);
+        });
     }
 
-    struct Worker;
-    class WorkerFeed;
-
-    class WorkerCmd {
-        public:
-        virtual ~WorkerCmd() = default;
-        virtual void exec(Worker *worker) = 0;
-    };
-
     class Worker {
         EventContext ec;
-        Event ev_ctl;
-        int ctl_fd[2]; /**< for control messages from dispatcher */
+        ThreadCall msgr;
         std::thread handle;
 
         public:
-        Worker() {
-            if (pipe2(ctl_fd, O_NONBLOCK))
-                throw ConnPoolError(std::string("failed to create worker pipe"));
-            ev_ctl = Event(ec, ctl_fd[0], Event::READ, [this](int fd, int) {
-                WorkerCmd *dcmd;
-                read(fd, &dcmd, sizeof(dcmd));
-                dcmd->exec(this);
-                delete dcmd;
-            });
-            ev_ctl.add();
-        }
-
-        ~Worker() {
-            close(ctl_fd[0]);
-            close(ctl_fd[1]);
-        }
+        Worker(): msgr(ec) {}
 
         /* the following functions are called by the dispatcher */
         void start() {
@@ -201,143 +176,69 @@ class ConnPool {
         }
 
         void feed(const conn_t &conn, int client_fd) {
-            auto dcmd = new WorkerFeed(conn, client_fd);
-            write(ctl_fd[1], &dcmd, sizeof(dcmd));
+            msgr.call([this, conn, client_fd](ThreadCall::Handle &) {
+                SALTICIDAE_LOG_INFO("worker %x got %s",
+                        std::this_thread::get_id(),
+                        std::string(*conn).c_str());
+                conn->get_send_buffer()
+                        .get_queue()
+                        .reg_handler(this->ec, [conn, client_fd]
+                                    (MPSCWriteBuffer::queue_t &) {
+                    if (conn->ready_send && conn->fd != -1)
+                        conn->send_data(client_fd, Event::WRITE);
+                    return false;
+                });
+                //auto conn_ptr = conn.get();
+                conn->ev_read = Event(ec, client_fd, Event::READ | Event::WRITE, [conn=conn](int fd, int what) {
+                    if (what & Event::READ)
+                        conn->recv_data(fd, what);
+                    else
+                        conn->send_data(fd, what);
+                });
+
+                //                        std::bind(&Conn::recv_data, conn_ptr, _1, _2));
+                //conn->ev_write = Event(ec, client_fd, Event::WRITE,
+                //                       std::bind(&Conn::send_data, conn_ptr, _1, _2));
+                conn->ev_read.add();
+                //conn->ev_write.add();
+            });
         }
 
         void stop() {
-            auto dcmd = new WorkerStop();
-            write(ctl_fd[1], &dcmd, sizeof(dcmd));
+            msgr.call([this](ThreadCall::Handle &) {
+                ec.stop();
+            });
         }
 
         std::thread &get_handle() { return handle; }
         const EventContext &get_ec() { return ec; }
     };
 
-    class WorkerFeed: public WorkerCmd {
-        conn_t conn;
-        int client_fd;
-
-        public:
-        WorkerFeed(const conn_t &conn, int client_fd):
-            conn(conn), client_fd(client_fd) {}
-        void exec(Worker *worker) override {
-            SALTICIDAE_LOG_INFO("worker %x got %s",
-                    std::this_thread::get_id(),
-                    std::string(*conn).c_str());
-            auto &ec = worker->get_ec();
-            conn->get_send_buffer()
-                    .get_queue()
-                    .reg_handler(ec, [conn=this->conn,
-                                    client_fd=this->client_fd](MPSCWriteBuffer::queue_t &) {
-                if (conn->ready_send && conn->fd != -1)
-                    conn->send_data(client_fd, Event::WRITE);
-                return false;
-            });
-            //auto conn_ptr = conn.get();
-            conn->ev_read = Event(ec, client_fd, Event::READ | Event::WRITE, [conn=conn](int fd, int what) {
-                if (what & Event::READ)
-                    conn->recv_data(fd, what);
-                else
-                    conn->send_data(fd, what);
-            });
-
-            //                        std::bind(&Conn::recv_data, conn_ptr, _1, _2));
-            //conn->ev_write = Event(ec, client_fd, Event::WRITE,
-            //                       std::bind(&Conn::send_data, conn_ptr, _1, _2));
-            conn->ev_read.add();
-            //conn->ev_write.add();
-        }
-    };
-
-    class WorkerStop: public WorkerCmd {
-        public:
-        void exec(Worker *worker) override { worker->get_ec().stop(); }
-    };
-
     /* related to workers */
     size_t nworker;
     salticidae::BoxObj<Worker[]> workers;
 
     void accept_client(int, int);
     conn_t add_conn(const conn_t &conn);
-    conn_t _connect(const NetAddr &addr);
-    void _post_terminate(int fd);
-    void _accept_listen(int listen_fd);
-    void _connect_listen(const conn_t &conn);
+    void terminate(int fd);
 
     protected:
-    class DispatchCmd {
-        public:
-        virtual ~DispatchCmd() = default;
-        virtual void exec(ConnPool *cpool) = 0;
-    };
+    conn_t _connect(const NetAddr &addr);
+    void _listen(NetAddr listen_addr);
 
     private:
-    class DspConnect: public DispatchCmd {
-        const NetAddr addr;
-        public:
-        DspConnect(const NetAddr &addr): addr(addr) {}
-        void exec(ConnPool *cpool) override {
-            cpool->update_conn(cpool->_connect(addr), true);
-        }
-    };
-
-    class DspPostTerm: public DispatchCmd {
-        int fd;
-        public:
-        DspPostTerm(int fd): fd(fd) {}
-        void exec(ConnPool *cpool) override {
-            cpool->_post_terminate(fd);
-        }
-    };
-
-    class DspMulticast: public DispatchCmd {
-        std::vector<conn_t> receivers;
-        bytearray_t data;
-        public:
-        DspMulticast(std::vector<conn_t> &&receivers, bytearray_t &&data):
-            receivers(std::move(receivers)),
-            data(std::move(data)) {}
-        void exec(ConnPool *) override {
-            for (auto &r: receivers) r->write(bytearray_t(data));
-        }
-    };
-
-    class DspAcceptListen: public DispatchCmd {
-        int listen_fd;
-        public:
-        DspAcceptListen(int listen_fd): listen_fd(listen_fd) {}
-        void exec(ConnPool *cpool) override {
-            cpool->_accept_listen(listen_fd);
-        }
-    };
 
-    class DspConnectListen: public DispatchCmd {
-        conn_t conn;
-        public:
-        DspConnectListen(const conn_t &conn): conn(conn) {}
-        void exec(ConnPool *cpool) override {
-            cpool->_connect_listen(conn);
-        }
-    };
-
-    class UserConn: public DispatchCmd {
-        conn_t conn;
-        bool connected;
-        public:
-        UserConn(const conn_t &conn, bool connected):
-            conn(conn), connected(connected) {}
-        void exec(ConnPool *cpool) override {
-            if (cpool->conn_cb)
-                cpool->conn_cb(*conn, connected);
-        }
-    };
-
-    void post_terminate(int fd) {
-        auto dcmd = new DspPostTerm(fd);
-        write(dlisten_fd[1], &dcmd, sizeof(dcmd));
-    }
+    //class DspMulticast: public DispatchCmd {
+    //    std::vector<conn_t> receivers;
+    //    bytearray_t data;
+    //    public:
+    //    DspMulticast(std::vector<conn_t> &&receivers, bytearray_t &&data):
+    //        receivers(std::move(receivers)),
+    //        data(std::move(data)) {}
+    //    void exec(ConnPool *) override {
+    //        for (auto &r: receivers) r->write(bytearray_t(data));
+    //    }
+    //};
 
     Worker &select_worker() {
         return workers[1];
@@ -346,7 +247,7 @@ class ConnPool {
     protected:
     EventContext ec;
     EventContext dispatcher_ec;
-    int dlisten_fd[2]; /**< for control command sent to the dispatcher */
+    BoxObj<ThreadCall> disp_tcall;
     /** Should be implemented by derived class to return a new Conn object. */
     virtual Conn *create_conn() = 0;
 
@@ -360,35 +261,13 @@ class ConnPool {
             conn_server_timeout(conn_server_timeout),
             seg_buff_size(seg_buff_size),
             listen_fd(-1),
-            nworker(std::min((size_t)1, nworker)),
+            nworker(std::max((size_t)1, nworker)),
             ec(ec) {
-        if (pipe2(mlisten_fd, O_NONBLOCK))
-            throw ConnPoolError(std::string("failed to create main pipe"));
-        if (pipe2(dlisten_fd, O_NONBLOCK))
-            throw ConnPoolError(std::string("failed to create dispatcher pipe"));
-
-        ev_mlisten = Event(ec, mlisten_fd[0], Event::READ, [this](int fd, int) {
-            DispatchCmd *dcmd;
-            read(fd, &dcmd, sizeof(dcmd));
-            dcmd->exec(this);
-            delete dcmd;
-        });
-        ev_mlisten.add();
-
         workers = new Worker[nworker];
         dispatcher_ec = workers[0].get_ec();
 
-        ev_dlisten = Event(dispatcher_ec, dlisten_fd[0], Event::READ, [this](int fd, int) {
-            DispatchCmd *dcmd;
-            read(fd, &dcmd, sizeof(dcmd));
-            dcmd->exec(this);
-            delete dcmd;
-        });
-        ev_dlisten.add();
-
-        SALTICIDAE_LOG_INFO("starting all threads...");
-        for (size_t i = 0; i < nworker; i++)
-            workers[i].start();
+        user_tcall = new ThreadCall(ec);
+        disp_tcall = new ThreadCall(dispatcher_ec);
     }
 
     ~ConnPool() {
@@ -404,24 +283,36 @@ class ConnPool {
             conn->on_close();
         }
         if (listen_fd != -1) close(listen_fd);
-        for (int i = 0; i < 2; i++)
-        {
-            close(mlisten_fd[i]);
-            close(dlisten_fd[i]);
-        }
     }
 
     ConnPool(const ConnPool &) = delete;
     ConnPool(ConnPool &&) = delete;
 
+    void start() {
+        SALTICIDAE_LOG_INFO("starting all threads...");
+        for (size_t i = 0; i < nworker; i++)
+            workers[i].start();
+    }
+
     /** Actively connect to remote addr. */
     conn_t connect(const NetAddr &addr, bool blocking = true) {
         if (blocking)
-            return _connect(addr);
+        {
+            auto ret = static_cast<conn_t *>(disp_tcall->call(
+                        [this, addr](ThreadCall::Handle &h) {
+                auto ptr = new conn_t(_connect(addr));
+                std::atomic_thread_fence(std::memory_order_release);
+                h.set_result(ptr);
+            }, true));
+            auto conn = *ret;
+            delete ret;
+            return std::move(conn);
+        }
         else
         {
-            auto dcmd = new DspConnect(addr);
-            write(dlisten_fd[1], &dcmd, sizeof(dcmd));
+            disp_tcall->call([this, addr](ThreadCall::Handle &) {
+                _connect(addr);
+            }, false);
             return nullptr;
         }
     }
@@ -429,7 +320,11 @@ class ConnPool {
     /** Listen for passive connections (connection initiated from remote).
      * Does not need to be called if do not want to accept any passive
      * connections. */
-    void listen(NetAddr listen_addr);
+    void listen(NetAddr listen_addr) {
+        disp_tcall->call([this, listen_addr](ThreadCall::Handle &) {
+            _listen(listen_addr);
+        }, true);
+    }
 
     template<typename Func>
     void reg_conn_handler(Func cb) { conn_cb = cb; }
diff --git a/include/salticidae/event.h b/include/salticidae/event.h
index c21644b..da27902 100644
--- a/include/salticidae/event.h
+++ b/include/salticidae/event.h
@@ -25,10 +25,12 @@
 #ifndef _SALTICIDAE_EVENT_H
 #define _SALTICIDAE_EVENT_H
 
+#include <condition_variable>
 #include <unistd.h>
 #include <uv.h>
 #include <sys/eventfd.h>
 
+#include "salticidae/type.h"
 #include "salticidae/queue.h"
 #include "salticidae/util.h"
 #include "salticidae/ref.h"
@@ -177,6 +179,90 @@ class Event {
     operator bool() const { return ev_fd != nullptr || ev_timer != nullptr; }
 };
 
+class ThreadNotifier {
+    std::condition_variable cv;
+    std::mutex mlock;
+    mutex_ul_t ul;
+    bool ready;
+    void *data;
+    public:
+    ThreadNotifier(): ul(mlock), ready(false) {}
+    void *wait() {
+        cv.wait(ul, [this]{ return ready; });
+        return data;
+    }
+    void notify(void *_data) { 
+        {
+            mutex_lg_t _(mlock);
+            ready = true;
+            data = _data;
+        }
+        cv.notify_all();
+    }
+};
+
+class ThreadCall {
+    int ctl_fd[2];
+    EventContext ec;
+    Event ev_listen;
+
+    public:
+    class Handle {
+        std::function<void(Handle &)> callback;
+        ThreadNotifier* notifier;
+        void *result;
+        friend ThreadCall;
+        public:
+        Handle(): notifier(nullptr), result(nullptr) {}
+        void exec() {
+            callback(*this);
+            if (notifier) notifier->notify(result);
+        }
+        void set_result(void *data) { result = data; }
+    };
+
+    ThreadCall() = default;
+    ThreadCall(const ThreadCall &) = delete;
+    ThreadCall(ThreadCall &&) = delete;
+    ThreadCall(EventContext ec): ec(ec) {
+        if (pipe2(ctl_fd, O_NONBLOCK))
+            throw SalticidaeError(std::string("ThreadCall: failed to create pipe"));
+        ev_listen = Event(ec, ctl_fd[0], Event::READ, [this](int fd, int) {
+            Handle *h;
+            read(fd, &h, sizeof(h));
+            h->exec();
+            delete h;
+        });
+        ev_listen.add();
+    }
+
+    ~ThreadCall() {
+        close(ctl_fd[0]);
+        close(ctl_fd[1]);
+    }
+
+    template<typename Func>
+    void *call(Func callback, bool blocking = false) {
+        auto h = new Handle();
+        h->callback = callback;
+        if (blocking)
+        {
+            ThreadNotifier notifier;
+            h->notifier = &notifier;
+            std::atomic_thread_fence(std::memory_order_release);
+            write(ctl_fd[1], &h, sizeof(h));
+            return notifier.wait();
+        }
+        else
+        {
+            std::atomic_thread_fence(std::memory_order_release);
+            write(ctl_fd[1], &h, sizeof(h));
+            return nullptr;
+        }
+    }
+};
+
+
 template<typename T>
 class MPSCQueueEventDriven: public MPSCQueue<T> {
     private:
diff --git a/include/salticidae/network.h b/include/salticidae/network.h
index 18406ea..e5165bf 100644
--- a/include/salticidae/network.h
+++ b/include/salticidae/network.h
@@ -206,7 +206,6 @@ class ClientNetwork: public MsgNetwork<OpcodeType> {
 
     private:
     std::unordered_map<NetAddr, typename MsgNet::conn_t> addr2conn;
-    std::mutex cn_mlock;
 
     public:
     class Conn: public MsgNet::Conn {
@@ -298,7 +297,6 @@ class PeerNetwork: public MsgNetwork<OpcodeType> {
         bool ping_timer_ok;
         bool pong_msg_ok;
         bool connected;
-        std::mutex mlock;
 
         Peer() = delete;
         Peer(NetAddr addr, conn_t conn, const EventContext &ec):
@@ -321,7 +319,6 @@ class PeerNetwork: public MsgNetwork<OpcodeType> {
     };
 
     std::unordered_map <NetAddr, BoxObj<Peer>> id2peer;
-    std::mutex pn_mlock;
 
     const IdentityMode id_mode;
     double retry_conn_delay;
@@ -355,30 +352,11 @@ class PeerNetwork: public MsgNetwork<OpcodeType> {
         }
     };
 
-    struct PingCmd: public ConnPool::DispatchCmd {
-        conn_t conn;
-        uint16_t port;
-        PingCmd(const conn_t &conn, uint16_t port):
-            conn(conn), port(port) {}
-        void exec(ConnPool *cpool) override {
-            auto pn = static_cast<PeerNetwork *>(cpool);
-            pn->_ping_msg_cb(conn, port);
-        }
-    };
-    
-    struct PongCmd: public PingCmd {
-        using PingCmd::PingCmd;
-        void exec(ConnPool *cpool) override {
-            auto pn = static_cast<PeerNetwork *>(cpool);
-            pn->_pong_msg_cb(this->conn, this->port);
-        }
-    };
-
     void msg_ping(MsgPing &&msg, Conn &conn);
     void msg_pong(MsgPong &&msg, Conn &conn);
     void _ping_msg_cb(const conn_t &conn, uint16_t port);
     void _pong_msg_cb(const conn_t &conn, uint16_t port);
-    bool check_new_conn(Conn &conn, uint16_t port);
+    bool check_new_conn(const conn_t &conn, uint16_t port);
     void start_active_conn(const NetAddr &paddr);
 
     protected:
@@ -402,12 +380,14 @@ class PeerNetwork: public MsgNetwork<OpcodeType> {
         id_mode(id_mode),
         retry_conn_delay(retry_conn_delay),
         ping_period(ping_period),
-        conn_timeout(conn_timeout) {}
+        conn_timeout(conn_timeout) {
+        this->reg_handler(generic_bind(&PeerNetwork::msg_ping, this, _1, _2));
+        this->reg_handler(generic_bind(&PeerNetwork::msg_pong, this, _1, _2));
+    }
 
     void add_peer(const NetAddr &paddr);
     const conn_t get_peer_conn(const NetAddr &paddr) const;
-    template<typename MsgType>
-    void _send_msg(const MsgType &msg, const Peer *peer);
+    using MsgNet::send_msg;
     template<typename MsgType>
     void send_msg(const MsgType &msg, const NetAddr &paddr);
     void listen(NetAddr listen_addr);
@@ -471,7 +451,7 @@ void PeerNetwork<O, _, __>::Conn::on_setup() {
     MsgNet::Conn::on_setup();
     auto pn = get_net();
     assert(!ev_timeout);
-    ev_timeout = Event(pn->ec, -1, 0, [this](int, int) {
+    ev_timeout = Event(pn->dispatcher_ec, -1, 0, [this](int, int) {
         SALTICIDAE_LOG_INFO("peer ping-pong timeout");
         this->terminate();
     });
@@ -483,18 +463,16 @@ void PeerNetwork<O, _, __>::Conn::on_setup() {
     /* the initial ping-pong to set up the connection */
     auto &conn = static_cast<Conn &>(*this);
     reset_timeout(pn->conn_timeout);
-    pn->MsgNet::send_msg(MsgPing(pn->listen_port), conn);
+    pn->send_msg(MsgPing(pn->listen_port), conn);
 }
 
 template<typename O, O _, O __>
 void PeerNetwork<O, _, __>::Conn::on_teardown() {
     MsgNet::Conn::on_teardown();
     auto pn = get_net();
-    mutex_lg_t _pn_lg(pn->pn_mlock);
     auto it = pn->id2peer.find(peer_id);
     if (it == pn->id2peer.end()) return;
     auto p = it->second.get();
-    mutex_lg_t _p_lg(p->mlock);
     if (this != p->conn.get()) return;
     p->ev_ping_timer.del();
     p->connected = false;
@@ -505,7 +483,6 @@ void PeerNetwork<O, _, __>::Conn::on_teardown() {
     // try to reconnect
     p->ev_retry_timer = Event(pn->dispatcher_ec, -1, 0,
             [pn, peer_id = this->peer_id](int, int) {
-        mutex_lg_t _pn_lg(pn->pn_mlock);
         pn->start_active_conn(peer_id);
     });
     p->ev_retry_timer.add_with_timeout(pn->gen_conn_timeout());
@@ -550,12 +527,11 @@ void PeerNetwork<O, _, __>::Peer::send_ping() {
     ping_timer_ok = false;
     pong_msg_ok = false;
     conn->reset_timeout(pn->conn_timeout);
-    pn->_send_msg(MsgPing(pn->listen_port), this);
+    pn->send_msg(MsgPing(pn->listen_port), *conn);
 }
 
 template<typename O, O _, O __>
 void PeerNetwork<O, _, __>::Peer::ping_timer(int, int) {
-    mutex_lg_t _p_lg(mlock);
     ping_timer_ok = true;
     if (pong_msg_ok)
     {
@@ -565,149 +541,132 @@ void PeerNetwork<O, _, __>::Peer::ping_timer(int, int) {
 }
 
 template<typename O, O _, O __>
-bool PeerNetwork<O, _, __>::check_new_conn(Conn &conn, uint16_t port) {
-    if (conn.peer_id.is_null())
+bool PeerNetwork<O, _, __>::check_new_conn(const conn_t &conn, uint16_t port) {
+    if (conn->peer_id.is_null())
     {   /* passive connections can eventually have ids after getting the port
            number in IP_BASED_PORT mode */
         assert(id_mode == IP_PORT_BASED);
-        conn.peer_id.ip = conn.get_addr().ip;
-        conn.peer_id.port = port;
+        conn->peer_id.ip = conn->get_addr().ip;
+        conn->peer_id.port = port;
     }
-    auto p = id2peer.find(conn.peer_id)->second.get();
-    mutex_lg_t _p_lg(p->mlock);
+    auto p = id2peer.find(conn->peer_id)->second.get();
     if (p->connected)
     {
-        if (conn.self() != p->conn)
+        if (conn != p->conn)
         {
-            conn.terminate();
+            conn->terminate();
             return true;
         }
         return false;
     }
-    p->reset_conn(static_pointer_cast<Conn>(conn.self()));
+    p->reset_conn(conn);
     p->connected = true;
     p->reset_ping_timer();
     p->send_ping();
     if (p->connected)
         SALTICIDAE_LOG_INFO("PeerNetwork: established connection with %s via %s",
-            std::string(conn.peer_id).c_str(), std::string(conn).c_str());
+            std::string(conn->peer_id).c_str(), std::string(*conn).c_str());
     return false;
 }
 
-template<typename O, O _, O __>
-void PeerNetwork<O, _, __>::_ping_msg_cb(const conn_t &conn, uint16_t port) {
-    mutex_lg_t _pn_lg(pn_mlock);
-    if (check_new_conn(*conn, port)) return;
-    auto p = id2peer.find(conn->peer_id)->second.get();
-    mutex_lg_t _p_lg(p->mlock);
-    _send_msg(MsgPong(this->listen_port), p);
-}
-
-template<typename O, O _, O __>
-void PeerNetwork<O, _, __>::_pong_msg_cb(const conn_t &conn, uint16_t port) {
-    mutex_lg_t _pn_lg(pn_mlock);
-    auto it = id2peer.find(conn->peer_id);
-    if (it == id2peer.end())
-    {
-        SALTICIDAE_LOG_WARN("pong message discarded");
-        return;
-    }
-    if (check_new_conn(*conn, port)) return;
-    auto p = it->second.get();
-    mutex_lg_t _p_lg(p->mlock);
-    p->pong_msg_ok = true;
-    if (p->ping_timer_ok)
-    {
-        p->reset_ping_timer();
-        p->send_ping();
-    }
-}
-
-/* end: functions invoked by the dispatcher */
-
-/* this function could be both invoked by the dispatcher and the user loop */
 template<typename O, O _, O __>
 void PeerNetwork<O, _, __>::start_active_conn(const NetAddr &addr) {
     auto p = id2peer.find(addr)->second.get();
-    mutex_lg_t _p_lg(p->mlock);
     if (p->connected) return;
-    auto conn = static_pointer_cast<Conn>(MsgNet::connect(addr));
+    auto conn = static_pointer_cast<Conn>(MsgNet::_connect(addr));
     assert(p->conn == nullptr);
     p->conn = conn;
 }
+/* end: functions invoked by the dispatcher */
 
 /* begin: functions invoked by the user loop */
 template<typename O, O _, O __>
-void PeerNetwork<O, _, __>::msg_ping(MsgPing &&msg, Conn &conn) {
+void PeerNetwork<O, _, __>::msg_ping(MsgPing &&msg, Conn &_conn) {
+    auto conn = static_pointer_cast<Conn>(_conn.self());
+    if (!conn) return;
     uint16_t port = msg.port;
-    SALTICIDAE_LOG_INFO("ping from %s, port %u", std::string(conn).c_str(), ntohs(port));
-    auto dcmd = new PingCmd(static_pointer_cast<Conn>(conn.self()), port);
-    write(this->dlisten_fd[1], &dcmd, sizeof(dcmd));
+    this->disp_tcall->call([this, conn, port](ThreadCall::Handle &msg) {
+        SALTICIDAE_LOG_INFO("ping from %s, port %u",
+                            std::string(*conn).c_str(), ntohs(port));
+        if (check_new_conn(conn, port)) return;
+        auto p = id2peer.find(conn->peer_id)->second.get();
+        send_msg(MsgPong(this->listen_port), *conn);
+    });
 }
 
 template<typename O, O _, O __>
-void PeerNetwork<O, _, __>::msg_pong(MsgPong &&msg, Conn &conn) {
-    auto dcmd = new PongCmd(static_pointer_cast<Conn>(conn.self()), msg.port);
-    write(this->dlisten_fd[1], &dcmd, sizeof(dcmd));
+void PeerNetwork<O, _, __>::msg_pong(MsgPong &&msg, Conn &_conn) {
+    auto conn = static_pointer_cast<Conn>(_conn.self());
+    if (!conn) return;
+    uint16_t port = msg.port;
+    this->disp_tcall->call([this, conn, port](ThreadCall::Handle &msg) {
+        auto it = id2peer.find(conn->peer_id);
+        if (it == id2peer.end())
+        {
+            SALTICIDAE_LOG_WARN("pong message discarded");
+            return;
+        }
+        if (check_new_conn(conn, port)) return;
+        auto p = it->second.get();
+        p->pong_msg_ok = true;
+        if (p->ping_timer_ok)
+        {
+            p->reset_ping_timer();
+            p->send_ping();
+        }
+    });
 }
 
 template<typename O, O _, O __>
 void PeerNetwork<O, _, __>::listen(NetAddr listen_addr) {
-    MsgNet::listen(listen_addr);
-    listen_port = listen_addr.port;
-    this->reg_handler(generic_bind(&PeerNetwork::msg_ping, this, _1, _2));
-    this->reg_handler(generic_bind(&PeerNetwork::msg_pong, this, _1, _2));
+    this->disp_tcall->call([this, listen_addr](ThreadCall::Handle &msg) {
+        MsgNet::_listen(listen_addr);
+        listen_port = listen_addr.port;
+    }, true);
 }
 
 template<typename O, O _, O __>
 void PeerNetwork<O, _, __>::add_peer(const NetAddr &addr) {
-    mutex_lg_t _pn_lg(pn_mlock);
-    auto it = id2peer.find(addr);
-    if (it != id2peer.end())
-        throw PeerNetworkError("peer already exists");
-    id2peer.insert(std::make_pair(addr, new Peer(addr, nullptr, this->dispatcher_ec)));
-    start_active_conn(addr);
+    this->disp_tcall->call([this, addr](ThreadCall::Handle &) {
+        auto it = id2peer.find(addr);
+        if (it != id2peer.end())
+            throw PeerNetworkError("peer already exists");
+        id2peer.insert(std::make_pair(addr, new Peer(addr, nullptr, this->dispatcher_ec)));
+        start_active_conn(addr);
+    }, true);
 }
 
 template<typename O, O _, O __>
 const typename PeerNetwork<O, _, __>::conn_t
 PeerNetwork<O, _, __>::get_peer_conn(const NetAddr &paddr) const {
-    mutex_lg_t _pn_lg(pn_mlock);
-    auto it = id2peer.find(paddr);
-    if (it == id2peer.end())
-        throw PeerNetworkError("peer does not exist");
-    return it->second->conn;
+    auto ret = static_cast<conn_t *>(this->disp_tcall->call(
+                [this, paddr](ThreadCall::Handle &h) {
+        auto it = id2peer.find(paddr);
+        if (it == id2peer.end())
+            throw PeerNetworkError("peer does not exist");
+        auto ptr = new conn_t(it->second->conn);
+        h.set_result(ptr);
+    }));
+    auto conn = *ret;
+    delete ret;
+    return std::move(conn);
 }
 
 template<typename O, O _, O __>
 bool PeerNetwork<O, _, __>::has_peer(const NetAddr &paddr) const {
-    mutex_lg_t _pn_lg(pn_mlock);
-    return id2peer.count(paddr);
-}
-
-template<typename O, O _, O __>
-template<typename MsgType>
-void PeerNetwork<O, _, __>::_send_msg(const MsgType &msg, const Peer *peer) {
-    if (peer->connected)
-        MsgNet::send_msg(msg, *(peer->conn));
-    else
-        SALTICIDAE_LOG_DEBUG("dropped");
+    auto ret = static_cast<bool *>(this->disp_tcall->call(
+                [this, paddr](ThreadCall::Handle &h) {
+        h.set_result(id2peer.count(paddr));
+    }));
+    auto has = *ret;
+    delete ret;
+    return has;
 }
 
 template<typename O, O _, O __>
 template<typename MsgType>
 void PeerNetwork<O, _, __>::send_msg(const MsgType &msg, const NetAddr &addr) {
-    mutex_lg_t _pn_lg(pn_mlock);
-    auto it = id2peer.find(addr);
-    if (it == id2peer.end())
-    {
-        SALTICIDAE_LOG_ERROR("sending to non-existing peer: %s",
-                            std::string(addr).c_str());
-        throw PeerNetworkError("peer does not exist");
-    }
-    auto p = it->second.get();
-    mutex_lg_t _p_lg(p->mlock);
-    _send_msg(msg, p);
+    send_msg(msg, *get_peer_conn(addr));
 }
 /* end: functions invoked by the user loop */
 
@@ -716,7 +675,6 @@ void ClientNetwork<OpcodeType>::Conn::on_setup() {
     MsgNet::Conn::on_setup();
     assert(this->get_mode() == Conn::PASSIVE);
     const auto &addr = this->get_addr();
-    mutex_lg_t _cn_lg(cn_mlock);
     auto cn = get_net();
     cn->addr2conn.erase(addr);
     cn->addr2conn.insert(
@@ -728,17 +686,22 @@ template<typename OpcodeType>
 void ClientNetwork<OpcodeType>::Conn::on_teardown() {
     MsgNet::Conn::on_teardown();
     assert(this->get_mode() == Conn::PASSIVE);
-    mutex_lg_t _cn_lg(cn_mlock);
     get_net()->addr2conn.erase(this->get_addr());
 }
 
 template<typename OpcodeType>
 template<typename MsgType>
 void ClientNetwork<OpcodeType>::send_msg(const MsgType &msg, const NetAddr &addr) {
-    mutex_lg_t _cn_lg(cn_mlock);
-    auto it = addr2conn.find(addr);
-    if (it == addr2conn.end()) return;
-    MsgNet::send_msg(msg, *(it->second));
+    auto ret = static_cast<conn_t *>(this->disp_tcall->call(
+                [this, addr](ThreadCall::Handle &h) {
+        auto it = addr2conn.find(addr);
+        if (it == addr2conn.end())
+            throw PeerNetworkError("client does not exist");
+        auto ptr = new conn_t(it->second->conn);
+        h.set_result(ptr);
+    }));
+    send_msg(msg, **ret);
+    delete ret;
 }
 
 template<typename O, O OPCODE_PING, O _>
diff --git a/include/salticidae/queue.h b/include/salticidae/queue.h
index 9045e2b..0b493ea 100644
--- a/include/salticidae/queue.h
+++ b/include/salticidae/queue.h
@@ -105,7 +105,7 @@ class MPMCQueue {
     void _enqueue(Block *nblk, U &&e) {
         new (&(nblk->elem)) T(std::forward<U>(e));
         nblk->next.store(nullptr, std::memory_order_release);
-        auto prev = tail.exchange(nblk, std::memory_order_relaxed);
+        auto prev = tail.exchange(nblk, std::memory_order_acq_rel);
         prev->next.store(nblk, std::memory_order_relaxed);
     }
 
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