我正在 Windows 10 中使用 TCP 实现通信系统(tx、rx)。我的问题是当 tx 向 rx 发送消息时,消息被延迟接收。当 tx 发送多条消息时,rx 仅在发送多条消息后才开始接收。我的猜测是 tx 一直等到它的缓冲区填满,然后才开始发送消息(在我的平台缓冲区长度为 512)。
如下图所示,在开始接收之前,出现这个错误:
ERROR receiving TCP, error #: 10014
我试图通过启用 TCP_NODELAY
选项来解决这个问题,以便立即发送消息(但没有成功)。然而,我对 TCP 的了解很浅,我不确定我是否做得对。
这是我的问题:
延迟发送(或接收)是否与 TCP 的 TCP_NODELAY
选项有关?
如果是,我是否正确启用了 TCP_NODELAY
如下:
int 是 = 1;
int resultt = setsockopt(serverSocket[0], IPPROTO_TCP, TCP_NODELAY, (char*)&yes, sizeof(int)); // 1 - on, 0 - off
if (resultt < 0)
std::cerr << "Error: TCP_NODELAY";
我是否将 TCP_NODELAY
选项放在服务器和客户端代码中的正确位置?
这是我的客户代码:
size_t IPTunnel::ipTunnelSend_tcp(size_t process) {
size_t remaining = process;
size_t result{ 0 };
size_t sent{ 0 };
while (remaining > 0) {
result = send(clientSocket[0], &(ip_tunnel_buffer[0]) + sent, (int) remaining, 0);
if (result >= 0) {
remaining -= result;
sent += result;
}
else {
if (getLogValue()) {
if ( result == 0) std::cerr << "No data send through TCP" << std::endl;
else std::cerr << "ERROR sending TCP, error #: " << WSAGetLastError() << std::endl;
}
break;
}
}
return sent;
}
和:
bool IPTunnel::client_tcp() {
// STEP 1 - Initialize Winsock
WSADATA wsData;
WORD ver = MAKEWORD(2, 2);
int wsResult = WSAStartup(ver, &wsData);
if (wsResult != 0)
{
std::cerr << "Can't start Winsock. Error code #" << wsResult << std::endl;
return false;
}
// STEP 2 - Create a socket
SOCKET s = socket(AF_INET, SOCK_STREAM, 0);
int yes = 1;
int resultt = setsockopt(clientSocket[0], IPPROTO_TCP, TCP_NODELAY, (char*)&yes,
sizeof(int));
if (resultt < 0)
std::cerr << "Error: TCP_NODELAY";
clientSocket.push_back(s);
if (clientSocket[0] == INVALID_SOCKET)
{
std::cerr << "Can't create socket, Error Code #" << WSAGetLastError() << std::endl;
WSACleanup();
return false;
}
// STEP 3 - Connect to the server
sockaddr_in hint;
hint.sin_family = AF_INET;
hint.sin_port = htons((u_short)localMachinePort);
inet_pton(AF_INET, remoteMachineIpAddress.c_str(), &hint.sin_addr);
int connResult{ -2 };
while (connResult != 0 || numberOfTrials == 0) {
connResult = connect(clientSocket[0], (sockaddr*)& hint, sizeof(hint));
if (connResult == SOCKET_ERROR)
{
std::cerr << "Can't connect to server, Err #" << WSAGetLastError() << std::endl;
std::cerr << "Waiting " << timeIntervalSeconds << " seconds." << std::endl;
Sleep(timeIntervalSeconds * 1000);
}
if (--numberOfTrials == 0) {
std::cerr << "Reached maximum number of attempts." << std::endl;
}
}
std::cerr << "Connected!\n";
return true;
}
这是我的服务器代码:
size_t IPTunnel::ipTunnelRecv_tcp(size_t space) {
char* recv_buffer = &ip_tunnel_buffer[0];
size_t remaining{ 0 };
if (outputSignals[0]->getValueType() == (signal_value_type::t_message))
{
remaining = ip_tunnel_buffer.size();
}
else
{
remaining = space * outputSignals[0]->valueTypeSizeOf();
}
size_t received{ 0 };
while (remaining > 0) {
auto aux{ 0 };
aux = recv(serverSocket[1], recv_buffer + received, (int) remaining, 0);
if (aux > 0) {
received += aux;
remaining -= received;
}
else {
if (getLogValue()) {
if (aux == 0) std::cerr << "No data received through TCP" << std::endl;
else std::cerr << "ERROR receiving TCP, error #: " << WSAGetLastError() << std::endl;
}
break;
}
}
return received;
}
和: bool IPTunnel::server_tcp() {
// STEP 1 - Initialize Winsock
WSADATA wsData;
WORD ver = MAKEWORD(2, 2);
int wsResult = WSAStartup(ver, &wsData);
if (wsResult != 0)
{
std::cerr << "Can't start Winsock. Error code #" << wsResult << std::endl;
return false;
}
// STEP 2 - Create a socket
SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
serverSocket.push_back(s);
if (serverSocket[0] == INVALID_SOCKET)
{
std::cerr << "Can't create socket, Error Code #" << WSAGetLastError() << std::endl;
WSACleanup();
return false;
}
// STEP 3 - Bind the socket
sockaddr_in hint;
hint.sin_family = AF_INET; // AF_INET=2, IPv4
inet_pton(AF_INET, localMachineIpAddress.data(), &hint.sin_addr.S_un.S_addr);
hint.sin_port = ntohs((u_short)localMachinePort);
char ipAddress[INET_ADDRSTRLEN];
inet_ntop(AF_INET, &hint.sin_addr.S_un.S_addr, ipAddress, INET_ADDRSTRLEN);
std::cerr << "The TCP server is running on IP address: " << ipAddress;
std::cerr << " Port: " << htons(hint.sin_port) << std::endl;
if (bind(serverSocket[0], (sockaddr*)& hint, sizeof(hint)) < 0) {
std::cerr << "Bind failed with error code #" << WSAGetLastError() << std::endl;
return false;
}
// STEP 4 - Listen on the socket for a client
if (listen(serverSocket[0], SOMAXCONN) == -1) {
std::cerr << "Listen error!" << std::endl;
return false;
}
// STEP 5 - Accept a connection from a client
sockaddr_in client;
int clientSize = sizeof(client);
s = accept(serverSocket[0], (sockaddr*) &client, &clientSize);
serverSocket.push_back(s);
// Provides information
char host[NI_MAXHOST];
char service[NI_MAXSERV];
ZeroMemory(host, NI_MAXHOST);
ZeroMemory(service, NI_MAXSERV);
if (getnameinfo((sockaddr*)& client, sizeof(client), host, NI_MAXHOST, service, NI_MAXSERV, 0) == 0)
{
std::cerr << host << " connected on port " << service << std::endl;
}
else
{
inet_ntop(AF_INET, &client.sin_addr, host, NI_MAXHOST);
std::cerr << host << " connected on port " << ntohs(client.sin_port) << std::endl;
}
int yes = 1;
int resultt = setsockopt(serverSocket[0], IPPROTO_TCP, TCP_NODELAY, (char*)&yes, sizeof(int)); // 1 - on, 0 - off
if (resultt < 0)
std::cerr << "Error: TCP_NODELAY_Server";
return true;
}
这里是发送消息(tx)的代码:
bool LoadFromCommandWindow::runBlock(void) {
int space = outputSignals[0]->space();
if (!space) return false;
if (flag && flag1)
{
std::getline(std::cin, plainData);
}
if (plainData.length() == 0)
{
flag = false;
return false;
}
else
{
data = plainData.substr(k, paddedDataLength);
if (data.length() != paddedDataLength) paddedData = padTo(data, paddedDataLength, '\0');
else paddedData = data;
outputSignals[0]->bufferPut((std::byte*) paddedData.c_str(), paddedDataLength); \\ This line puts the message into buffer
k += data.length();
if (k != plainData.length()) flag1 = false;
else
{
flag1 = true;
k = 0;
}
}
return flag;
}
std::string LoadFromCommandWindow::padTo(std::string str, const size_t num, const char paddingChar = '\0')
{
if (num > str.size())
str.insert(str.size(), num - str.size(), paddingChar);
return str;
}
这里是接收消息的代码(rx):
bool PrintData::runBlock(void) {
int ready = inputSignals[0]->ready();
int space = outputSignals[0]->space();
int process = std::min(ready, space);
if (process == 0) return false;
inputSignals[0]->bufferGet((std::byte*)decryptedData, decryptedDataLength);
decryptedDataLength = unpad(decryptedDataLength, decryptedData, '\0');
for (size_t i = 0; i < decryptedDataLength; i++)
{
std::cout << decryptedData[i];
}
std::cout << std::endl;
outputSignals[0]->bufferPut((std::byte*)decryptedData, decryptedDataLength);
decryptedDataLength = 496;
return true;
}
谢谢!
答案 0 :(得分:0)
套接字应该是
expose 80
应该够了,但要看情况
防弹的东西是使用整个缓冲区传输,缓冲区大小为系统最大值
https://stackoverflow.com/a/64726689/7172363