【C++】Linux平台C++实现Socket通信(Unix域、TCP/IP、UDP)
Unix 域套接字
Unix 域套接字非常适合在同一台机器上的不同进程之间进行高效的通信。由于它们不需要网络协议栈,因此在性能上通常优于 TCP/IP 套接字。
Socket server端
StartSocketServer.cpp源代码:
#include <iostream>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <cstring>
#include <string.h>
constexpr const char *SOCKET_PATH = "./socket"; // Unix socket 文件路径
void StartSocketServer() {
// 创建一个 Unix 域套接字
std::cout << "Starting Socket Server..." << std::endl;
int serverSocketFd = socket(AF_UNIX, SOCK_STREAM, 0);
if (serverSocketFd == -1) {
std::cerr << "Error creating socket" << std::endl;
return;
}
std::cout << "Socket created with file descriptor: " << serverSocketFd << std::endl;
// 绑定套接字到指定路径
sockaddr_un serverAddr;
serverAddr.sun_family = AF_UNIX;
strncpy(serverAddr.sun_path, SOCKET_PATH, sizeof(serverAddr.sun_path) - 1);
unlink(serverAddr.sun_path); // 确保路径不存在
if (bind(serverSocketFd, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) == -1) {
std::cerr << "Error binding socket" << std::endl;
close(serverSocketFd);
return;
}
// 监听传入的连接
if (listen(serverSocketFd, 5) == -1) {
std::cerr << "Error listening for connections" << std::endl;
close(serverSocketFd);
return;
}
std::cout << "Server is listening for incoming connections..." << std::endl;
while (true) {
// 接受传入的连接
std::cout << "Waiting for client connection..." << std::endl;
int clientSocketFd = accept(serverSocketFd, nullptr, nullptr);
if (clientSocketFd == -1) {
std::cerr << "Error accepting connection" << std::endl;
close(serverSocketFd);
return;
}
std::cout << "Client connected, clientSocketFd: " << clientSocketFd << std::endl;
// 接收来自客户端的数据
char buffer[256];
ssize_t bytesReceived = recv(clientSocketFd, buffer, sizeof(buffer) - 1, 0);
if (bytesReceived > 0) {
buffer[bytesReceived] = '\0'; // Null-terminate the received data
std::cout << "Received data: " << buffer << std::endl;
// 发送响应给客户端
const char *response = "OK";
send(clientSocketFd, response, strlen(response), 0);
std::cout << "Response sent to client." << std::endl;
} else {
std::cerr << "Error receiving data" << std::endl;
}
// 关闭客户端套接字
close(clientSocketFd);
std::cout << "Client socket closed." << std::endl;
}
// 关闭服务器套接字(虽然在此代码中不会到达)
close(serverSocketFd);
}
int main() {
std::cout << "Hello, World!" << std::endl;
StartSocketServer(); // 启动套接字服务器
return 0;
}
使用g++编译生成可执行文件StartSocketServer:
g++ -o StartSocketServer StartSocketServer.cpp
启动socket server端:
./StartSocketServer
启动后socket server端打印如下:
Hello, World!
Starting Socket Server...
Socket created with file descriptor: 3
Server is listening for incoming connections...
Waiting for client connection...
Socket client端
StartSocketClient.cpp源代码:
#include <iostream>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <cstring>
constexpr const char *SOCKET_PATH = "./socket"; // Unix socket 文件路径
void StartSocketClient() {
// 创建一个 Unix 域套接字
int clientSocketFd = socket(AF_UNIX, SOCK_STREAM, 0);
if (clientSocketFd == -1) {
std::cerr << "Error creating socket" << std::endl;
return;
}
// 设置服务器地址结构
sockaddr_un serverAddr;
serverAddr.sun_family = AF_UNIX;
strncpy(serverAddr.sun_path, SOCKET_PATH, sizeof(serverAddr.sun_path) - 1);
// 连接到服务器
if (connect(clientSocketFd, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) == -1) {
std::cerr << "Error connecting to socket" << std::endl;
close(clientSocketFd);
return;
}
std::cout << "Connected to server!" << std::endl;
// 向服务器发送消息
const char *message = "Message sent by client!";
ssize_t bytesSent = send(clientSocketFd, message, strlen(message), 0);
if (bytesSent == -1) {
std::cerr << "Error sending message" << std::endl;
} else {
std::cout << "Message sent: " << message << std::endl;
}
// 可选:接收来自服务器的响应
char buffer[256];
ssize_t bytesReceived = recv(clientSocketFd, buffer, sizeof(buffer) - 1, 0);
if (bytesReceived > 0) {
buffer[bytesReceived] = '\0'; // Null-terminate the received data
std::cout << "Received from server: " << buffer << std::endl;
} else if (bytesReceived == -1) {
std::cerr << "Error receiving data" << std::endl;
}
// 关闭套接字
close(clientSocketFd);
}
int main() {
StartSocketClient(); // 启动套接字客户端
return 0;
}
使用g++编译生成可执行文件StartSocketClient:
g++ -o StartSocketClient StartSocketClient.cpp
启动socket client端:
./StartSocketClient
启动后socket client端打印如下:
Connected to server!
Message sent: Message sent by client!
Received from server: OK
socket server端打印如下:
Hello, World!
Starting Socket Server...
Socket created with file descriptor: 3
Server is listening for incoming connections...
Waiting for client connection...
Client connected, clientSocketFd: 4
Received data: Message sent by client!
Response sent to client.
Client socket closed.
Waiting for client connection...
TCP/IP 套接字
TCP/IP 套接字是最常用的网络通信方式,适用于通过网络进行通信的应用程序。它使用 TCP 协议提供可靠的、面向连接的通信。
Socket server端
#include <iostream>
#include <unistd.h>
#include <arpa/inet.h>
#include <cstring>
constexpr const char *SERVER_IP = "127.0.0.1"; // 本地回环地址
constexpr const int SERVER_PORT = 8080; // 端口号
void StartTcpServer() {
int serverSocketFd = socket(AF_INET, SOCK_STREAM, 0);
if (serverSocketFd == -1) {
std::cerr << "Error creating socket" << std::endl;
return;
}
sockaddr_in serverAddr;
serverAddr.sin_family = AF_INET;
serverAddr.sin_addr.s_addr = inet_addr(SERVER_IP);
serverAddr.sin_port = htons(SERVER_PORT);
if (bind(serverSocketFd, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) == -1) {
std::cerr << "Error binding socket" << std::endl;
close(serverSocketFd);
return;
}
if (listen(serverSocketFd, 5) == -1) {
std::cerr << "Error listening for connections" << std::endl;
close(serverSocketFd);
return;
}
std::cout << "TCP Server is listening for incoming connections..." << std::endl;
while (true) {
int clientSocketFd = accept(serverSocketFd, nullptr, nullptr);
if (clientSocketFd == -1) {
std::cerr << "Error accepting connection" << std::endl;
close(serverSocketFd);
return;
}
char buffer[256];
ssize_t bytesReceived = recv(clientSocketFd, buffer, sizeof(buffer) - 1, 0);
if (bytesReceived > 0) {
buffer[bytesReceived] = '\0';
std::cout << "Received data: " << buffer << std::endl;
const char *response = "OK";
send(clientSocketFd, response, strlen(response), 0);
}
close(clientSocketFd);
}
close(serverSocketFd);
}
int main() {
StartTcpServer();
return 0;
}
Socket client端
#include <iostream>
#include <unistd.h>
#include <arpa/inet.h>
#include <cstring>
constexpr const char *SERVER_IP = "127.0.0.1"; // 本地回环地址
constexpr const int SERVER_PORT = 8080; // 端口号
void StartTcpClient() {
int clientSocketFd = socket(AF_INET, SOCK_STREAM, 0);
if (clientSocketFd == -1) {
std::cerr << "Error creating socket" << std::endl;
return;
}
sockaddr_in serverAddr;
serverAddr.sin_family = AF_INET;
serverAddr.sin_addr.s_addr = inet_addr(SERVER_IP);
serverAddr.sin_port = htons(SERVER_PORT);
if (connect(clientSocketFd, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) == -1) {
std::cerr << "Error connecting to server" << std::endl;
close(clientSocketFd);
return;
}
const char *message = "Hello from TCP client!";
send(clientSocketFd, message, strlen(message), 0);
char buffer[256];
ssize_t bytesReceived = recv(clientSocketFd, buffer, sizeof(buffer) - 1, 0);
if (bytesReceived > 0) {
buffer[bytesReceived] = '\0';
std::cout << "Received from server: " << buffer << std::endl;
}
close(clientSocketFd);
}
int main() {
StartTcpClient();
return 0;
}
UDP 套接字
UDP 套接字使用无连接的 UDP 协议,适用于需要快速传输但不需要可靠性的应用(如视频流、在线游戏等)。
Socket server端
#include <iostream>
#include <unistd.h>
#include <arpa/inet.h>
#include <cstring>
constexpr const char *SERVER_IP = "127.0.0.1"; // 本地回环地址
constexpr const int SERVER_PORT = 8080; // 端口号
void StartUdpServer() {
int serverSocketFd = socket(AF_INET, SOCK_DGRAM, 0);
if (serverSocketFd == -1) {
std::cerr << "Error creating socket" << std::endl;
return;
}
sockaddr_in serverAddr;
serverAddr.sin_family = AF_INET;
serverAddr.sin_addr.s_addr = inet_addr(SERVER_IP);
serverAddr.sin_port = htons(SERVER_PORT);
if (bind(serverSocketFd, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) == -1) {
std::cerr << "Error binding socket" << std::endl;
close(serverSocketFd);
return;
}
std::cout << "UDP Server is listening for incoming messages..." << std::endl;
while (true) {
char buffer[256];
sockaddr_in clientAddr;
socklen_t clientAddrLen = sizeof(clientAddr);
ssize_t bytesReceived = recvfrom(serverSocketFd, buffer, sizeof(buffer) - 1, 0,
(struct sockaddr *)&clientAddr, &clientAddrLen);
if (bytesReceived > 0) {
buffer[bytesReceived] = '\0';
std::cout << "Received data: " << buffer << std::endl;
// 发送响应给客户端
const char *response = "OK";
sendto(serverSocketFd, response, strlen(response), 0,
(struct sockaddr *)&clientAddr, clientAddrLen);
}
}
close(serverSocketFd);
}
int main() {
StartUdpServer();
return 0;
}
Socket client端
#include <iostream>
#include <unistd.h>
#include <arpa/inet.h>
#include <cstring>
constexpr const char *SERVER_IP = "127.0.0.1"; // 本地回环地址
constexpr const int SERVER_PORT = 8080; // 端口号
void StartUdpClient() {
int clientSocketFd = socket(AF_INET, SOCK_DGRAM, 0);
if (clientSocketFd == -1) {
std::cerr << "Error creating socket" << std::endl;
return;
}
sockaddr_in serverAddr;
serverAddr.sin_family = AF_INET;
serverAddr.sin_addr.s_addr = inet_addr(SERVER_IP);
serverAddr.sin_port = htons(SERVER_PORT);
const char *message = "Hello from UDP client!";
sendto(clientSocketFd, message, strlen(message), 0,
(struct sockaddr *)&serverAddr, sizeof(serverAddr));
char buffer[256];
sockaddr_in fromAddr;
socklen_t fromAddrLen = sizeof(fromAddr);
ssize_t bytesReceived = recvfrom(clientSocketFd, buffer, sizeof(buffer) - 1, 0,
(struct sockaddr *)&fromAddr, &fromAddrLen);
if (bytesReceived > 0) {
buffer[bytesReceived] = '\0';
std::cout << "Received from server: " << buffer << std::endl;
}
close(clientSocketFd);
}
int main() {
StartUdpClient();
return 0;
}