Scripting: reimplement protocol over plan UDP using boost::asio

dist/scripting/citra.py

@@ -1,22 +1,22 @@
-import zmq
 import struct
 import random
 import enum
+import socket
 
 CURRENT_REQUEST_VERSION = 1
 MAX_REQUEST_DATA_SIZE = 32
+MAX_PACKET_SIZE = 48
 
 class RequestType(enum.IntEnum):
     ReadMemory = 1,
     WriteMemory = 2
 
-CITRA_PORT = "45987"
+CITRA_PORT = 45987
 
 class Citra:
     def __init__(self, address="127.0.0.1", port=CITRA_PORT):
-        self.context = zmq.Context()
-        self.socket = self.context.socket(zmq.REQ)
-        self.socket.connect("tcp://" + address + ":" + port)
+        self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        self.address = address
 
     def is_connected(self):
         return self.socket is not None
@@ -45,9 +45,9 @@ class Citra:
             request_data = struct.pack("II", read_address, temp_read_size)
             request, request_id = self._generate_header(RequestType.ReadMemory, len(request_data))
             request += request_data
-            self.socket.send(request)
+            self.socket.sendto(request, (self.address, CITRA_PORT))
 
-            raw_reply = self.socket.recv()
+            raw_reply = self.socket.recv(MAX_PACKET_SIZE)
             reply_data = self._read_and_validate_header(raw_reply, request_id, RequestType.ReadMemory)
 
             if reply_data:
@@ -77,9 +77,9 @@ class Citra:
             request_data += write_contents[:temp_write_size]
             request, request_id = self._generate_header(RequestType.WriteMemory, len(request_data))
             request += request_data
-            self.socket.send(request)
+            self.socket.sendto(request, (self.address, CITRA_PORT))
 
-            raw_reply = self.socket.recv()
+            raw_reply = self.socket.recv(MAX_PACKET_SIZE)
             reply_data = self._read_and_validate_header(raw_reply, request_id, RequestType.WriteMemory)
 
             if None != reply_data:

src/core/CMakeLists.txt

@@ -439,8 +439,8 @@ if (ENABLE_SCRIPTING)
         rpc/rpc_server.h
         rpc/server.cpp
         rpc/server.h
-        rpc/zmq_server.cpp
-        rpc/zmq_server.h
+        rpc/udp_server.cpp
+        rpc/udp_server.h
     )
 endif()
 

src/core/rpc/rpc_server.h

@@ -13,6 +13,9 @@
 
 namespace RPC {
 
+class Packet;
+struct PacketHeader;
+
 class RPCServer {
 public:
     RPCServer();

src/core/rpc/server.cpp

@@ -1,27 +1,30 @@
 #include <functional>
-
 #include "core/core.h"
+#include "core/rpc/packet.h"
 #include "core/rpc/rpc_server.h"
 #include "core/rpc/server.h"
+#include "core/rpc/udp_server.h"
 
 namespace RPC {
 
 Server::Server(RPCServer& rpc_server) : rpc_server(rpc_server) {}
 
+Server::~Server() = default;
+
 void Server::Start() {
-    const auto callback = [this](std::unique_ptr<RPC::Packet> new_request) {
+    const auto callback = [this](std::unique_ptr<Packet> new_request) {
         NewRequestCallback(std::move(new_request));
     };
 
     try {
-        zmq_server = std::make_unique<ZMQServer>(callback);
+        udp_server = std::make_unique<UDPServer>(callback);
     } catch (...) {
-        LOG_ERROR(RPC_Server, "Error starting ZeroMQ server");
+        LOG_ERROR(RPC_Server, "Error starting UDP server");
     }
 }
 
 void Server::Stop() {
-    zmq_server.reset();
+    udp_server.reset();
 }
 
 void Server::NewRequestCallback(std::unique_ptr<RPC::Packet> new_request) {

src/core/rpc/server.h

@@ -4,24 +4,25 @@
 
 #pragma once
 
-#include "core/rpc/packet.h"
-#include "core/rpc/zmq_server.h"
+#include <memory>
 
 namespace RPC {
 
 class RPCServer;
-class ZMQServer;
+class UDPServer;
+class Packet;
 
 class Server {
 public:
     Server(RPCServer& rpc_server);
+    ~Server();
     void Start();
     void Stop();
-    void NewRequestCallback(std::unique_ptr<RPC::Packet> new_request);
+    void NewRequestCallback(std::unique_ptr<Packet> new_request);
 
 private:
     RPCServer& rpc_server;
-    std::unique_ptr<ZMQServer> zmq_server;
+    std::unique_ptr<UDPServer> udp_server;
 };
 
 } // namespace RPC

src/core/rpc/udp_server.cpp

@@ -0,0 +1,100 @@
+// Copyright 2019 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <thread>
+#include <boost/asio.hpp>
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "core/rpc/packet.h"
+#include "core/rpc/udp_server.h"
+
+namespace RPC {
+
+class UDPServer::Impl {
+public:
+    explicit Impl(std::function<void(std::unique_ptr<Packet>)> new_request_callback)
+        // Use a random high port
+        // TODO: Make configurable or increment port number on failure
+        : socket(io_context, boost::asio::ip::udp::endpoint(boost::asio::ip::udp::v4(), 45987)),
+          new_request_callback(std::move(new_request_callback)) {
+
+        StartReceive();
+        worker_thread = std::thread([this] {
+            io_context.run();
+            this->new_request_callback(nullptr);
+        });
+    }
+
+    ~Impl() {
+        io_context.stop();
+        worker_thread.join();
+    }
+
+private:
+    void StartReceive() {
+        socket.async_receive_from(boost::asio::buffer(request_buffer), remote_endpoint,
+                                  [this](const boost::system::error_code& error, std::size_t size) {
+                                      HandleReceive(error, size);
+                                  });
+    }
+
+    void HandleReceive(const boost::system::error_code& error, std::size_t size) {
+        if (error) {
+            LOG_WARNING(RPC_Server, "Failed to receive data on UDP socket: {}", error.message());
+        } else if (size >= MIN_PACKET_SIZE && size <= MAX_PACKET_SIZE) {
+            PacketHeader header;
+            std::memcpy(&header, request_buffer.data(), sizeof(header));
+            if ((size - MIN_PACKET_SIZE) == header.packet_size) {
+                u8* data = request_buffer.data() + MIN_PACKET_SIZE;
+                std::function<void(Packet&)> send_reply_callback =
+                    std::bind(&Impl::SendReply, this, remote_endpoint, std::placeholders::_1);
+                std::unique_ptr<Packet> new_packet =
+                    std::make_unique<Packet>(header, data, send_reply_callback);
+
+                // Send the request to the upper layer for handling
+                new_request_callback(std::move(new_packet));
+            }
+        } else {
+            LOG_WARNING(RPC_Server, "Received message with wrong size: {}", size);
+        }
+        StartReceive();
+    }
+
+    void SendReply(boost::asio::ip::udp::endpoint endpoint, Packet& reply_packet) {
+        std::vector<u8> reply_buffer(MIN_PACKET_SIZE + reply_packet.GetPacketDataSize());
+        auto reply_header = reply_packet.GetHeader();
+
+        std::memcpy(reply_buffer.data(), &reply_header, sizeof(reply_header));
+        std::memcpy(reply_buffer.data() + (4 * sizeof(u32)), reply_packet.GetPacketData().data(),
+                    reply_packet.GetPacketDataSize());
+
+        boost::system::error_code error;
+        socket.send_to(boost::asio::buffer(reply_buffer), endpoint, 0, error);
+
+        if (error) {
+            LOG_WARNING(RPC_Server, "Failed to send reply: {}", error.message());
+        } else {
+            LOG_INFO(RPC_Server, "Sent reply version({}) id=({}) type=({}) size=({})",
+                     reply_packet.GetVersion(), reply_packet.GetId(),
+                     static_cast<u32>(reply_packet.GetPacketType()),
+                     reply_packet.GetPacketDataSize());
+        }
+    }
+
+    std::thread worker_thread;
+
+    boost::asio::io_context io_context;
+    boost::asio::ip::udp::socket socket;
+    std::array<u8, MAX_PACKET_SIZE> request_buffer;
+    boost::asio::ip::udp::endpoint remote_endpoint;
+
+    std::function<void(std::unique_ptr<Packet>)> new_request_callback;
+};
+
+UDPServer::UDPServer(std::function<void(std::unique_ptr<Packet>)> new_request_callback)
+    : impl(std::make_unique<Impl>(new_request_callback)) {}
+
+UDPServer::~UDPServer() = default;
+
+} // namespace RPC

src/core/rpc/udp_server.h

@@ -0,0 +1,24 @@
+// Copyright 2019 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <functional>
+#include <memory>
+
+namespace RPC {
+
+class Packet;
+
+class UDPServer {
+public:
+    explicit UDPServer(std::function<void(std::unique_ptr<Packet>)> new_request_callback);
+    ~UDPServer();
+
+private:
+    class Impl;
+    std::unique_ptr<Impl> impl;
+};
+
+} // namespace RPC

src/core/rpc/zmq_server.cpp

@@ -1,79 +0,0 @@
-#include "common/common_types.h"
-#include "core/core.h"
-#include "core/rpc/packet.h"
-#include "core/rpc/zmq_server.h"
-
-namespace RPC {
-
-ZMQServer::ZMQServer(std::function<void(std::unique_ptr<Packet>)> new_request_callback)
-    : zmq_context(std::move(std::make_unique<zmq::context_t>(1))),
-      zmq_socket(std::move(std::make_unique<zmq::socket_t>(*zmq_context, ZMQ_REP))),
-      new_request_callback(std::move(new_request_callback)) {
-    // Use a random high port
-    // TODO: Make configurable or increment port number on failure
-    zmq_socket->bind("tcp://127.0.0.1:45987");
-    LOG_INFO(RPC_Server, "ZeroMQ listening on port 45987");
-
-    worker_thread = std::thread(&ZMQServer::WorkerLoop, this);
-}
-
-ZMQServer::~ZMQServer() {
-    // Triggering the zmq_context destructor will cancel
-    // any blocking calls to zmq_socket->recv()
-    running = false;
-    zmq_context.reset();
-    worker_thread.join();
-
-    LOG_INFO(RPC_Server, "ZeroMQ stopped");
-}
-
-void ZMQServer::WorkerLoop() {
-    zmq::message_t request;
-    while (running) {
-        try {
-            if (zmq_socket->recv(&request, 0)) {
-                if (request.size() >= MIN_PACKET_SIZE && request.size() <= MAX_PACKET_SIZE) {
-                    u8* request_buffer = static_cast<u8*>(request.data());
-                    PacketHeader header;
-                    std::memcpy(&header, request_buffer, sizeof(header));
-                    if ((request.size() - MIN_PACKET_SIZE) == header.packet_size) {
-                        u8* data = request_buffer + MIN_PACKET_SIZE;
-                        std::function<void(Packet&)> send_reply_callback =
-                            std::bind(&ZMQServer::SendReply, this, std::placeholders::_1);
-                        std::unique_ptr<Packet> new_packet =
-                            std::make_unique<Packet>(header, data, send_reply_callback);
-
-                        // Send the request to the upper layer for handling
-                        new_request_callback(std::move(new_packet));
-                    }
-                }
-            }
-        } catch (...) {
-            LOG_WARNING(RPC_Server, "Failed to receive data on ZeroMQ socket");
-        }
-    }
-    std::unique_ptr<Packet> end_packet = nullptr;
-    new_request_callback(std::move(end_packet));
-    // Destroying the socket must be done by this thread.
-    zmq_socket.reset();
-}
-
-void ZMQServer::SendReply(Packet& reply_packet) {
-    if (running) {
-        auto reply_buffer =
-            std::make_unique<u8[]>(MIN_PACKET_SIZE + reply_packet.GetPacketDataSize());
-        auto reply_header = reply_packet.GetHeader();
-
-        std::memcpy(reply_buffer.get(), &reply_header, sizeof(reply_header));
-        std::memcpy(reply_buffer.get() + (4 * sizeof(u32)), reply_packet.GetPacketData().data(),
-                    reply_packet.GetPacketDataSize());
-
-        zmq_socket->send(reply_buffer.get(), MIN_PACKET_SIZE + reply_packet.GetPacketDataSize());
-
-        LOG_INFO(RPC_Server, "Sent reply version({}) id=({}) type=({}) size=({})",
-                 reply_packet.GetVersion(), reply_packet.GetId(),
-                 static_cast<u32>(reply_packet.GetPacketType()), reply_packet.GetPacketDataSize());
-    }
-}
-
-}; // namespace RPC

src/core/rpc/zmq_server.h

@@ -1,34 +0,0 @@
-// Copyright 2018 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include <functional>
-#include <thread>
-#define ZMQ_STATIC
-#include <zmq.hpp>
-
-namespace RPC {
-
-class Packet;
-
-class ZMQServer {
-public:
-    explicit ZMQServer(std::function<void(std::unique_ptr<Packet>)> new_request_callback);
-    ~ZMQServer();
-
-private:
-    void WorkerLoop();
-    void SendReply(Packet& request);
-
-    std::thread worker_thread;
-    std::atomic_bool running = true;
-
-    std::unique_ptr<zmq::context_t> zmq_context;
-    std::unique_ptr<zmq::socket_t> zmq_socket;
-
-    std::function<void(std::unique_ptr<Packet>)> new_request_callback;
-};
-
-} // namespace RPC