linux下套接字服务机和客户机通信的例程

下面是一个简单的 Linux 下套接字服务端和客户端通信的例程，使用 C 语言编写：

服务端代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main() {
    int server_fd, new_socket;
    struct sockaddr_in address;
    int addrlen = sizeof(address);
    char buffer[BUFFER_SIZE] = {0};
    char *hello = "Hello from server";

    // 创建 socket
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("socket failed");
        exit(EXIT_FAILURE);
    }

    // 设置地址和端口
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);

    // 绑定 socket
    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    // 监听 socket
    if (listen(server_fd, 3) < 0) {
        perror("listen failed");
        exit(EXIT_FAILURE);
    }

    // 接受连接请求
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen)) < 0) {
        perror("accept failed");
        exit(EXIT_FAILURE);
    }

    // 读取客户端发送的消息
    int valread = read(new_socket, buffer, BUFFER_SIZE);
    printf("Client: %s\n", buffer);

    // 发送消息给客户端
    send(new_socket, hello, strlen(hello), 0);
    printf("Hello message sent\n");

    // 关闭 socket
    close(new_socket);
    close(server_fd);

    return 0;
}

客户端代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main() {
    int sock = 0;
    struct sockaddr_in serv_addr;
    char buffer[BUFFER_SIZE] = {0};
    char *hello = "Hello from client";

    // 创建 socket
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        printf("\n Socket creation error \n");
        return -1;
    }

    // 设置地址和端口
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);

    // 将 IP 地址转换为网络字节序
    if(inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr)<=0) {
        printf("\nInvalid address/ Address not supported \n");
        return -1;
    }

    // 连接到服务器
    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
        printf("\nConnection Failed \n");
        return -1;
    }

    // 发送消息给服务器
    send(sock, hello, strlen(hello), 0);
    printf("Hello message sent\n");

    // 读取服务器发送的消息
    int valread = read(sock, buffer, BUFFER_SIZE);
    printf("Server: %s\n", buffer);

    // 关闭 socket
    close(sock);

    return 0;
}

这个例程简单地演示了服务端和客户端通过套接字进行通信的过程。服务端创建一个 socket 并监听端口，等待客户端连接。客户端创建一个 socket 并连接到服务端。服务端和客户端之间通过 send() 和 read() 函数进行消息的发送和接收。最后，服务端和客户端关闭它们的 socket。