socket测试

client.c：

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

#define SERVER_IP "127.0.0.1"
#define PORT 7312
#define MAX_MSG_SIZE 1024

int main() {
    int client_socket;
    struct sockaddr_in server_address;

    // 创建客户端套接字
    client_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (client_socket == -1) {
        perror("创建套接字失败");
        exit(EXIT_FAILURE);
    }

    // 设置服务器地址
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = inet_addr(SERVER_IP);
    server_address.sin_port = htons(PORT);

    // 建立与服务器的连接
    if (connect(client_socket, (struct sockaddr *)&server_address, sizeof(server_address)) < 0) {
        perror("连接服务器失败");
        exit(EXIT_FAILURE);
    }

    // 输入消息
    char input[MAX_MSG_SIZE];
    printf("请输入消息：");
    fgets(input, sizeof(input), stdin);

    // 检查消息格式
    if (strncmp(input, "客户端实现者20211312：", 17) != 0) {
        perror("错误：消息格式不正确");
        exit(EXIT_FAILURE);
    }

    // 向服务器发送消息
    write(client_socket, input, strlen(input));

    // 读取服务器的响应
    char response[MAX_MSG_SIZE];
    ssize_t bytesRead = read(client_socket, response, sizeof(response));
    if (bytesRead > 0) {
        printf("服务器的响应：\n%s\n", response);
    }

    // 关闭套接字
    close(client_socket);

    return 0;
}

server.c

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

#define PORT 7312
#define MAX_MSG_SIZE 1024

void handle_client(int client_socket) {
    char buffer[MAX_MSG_SIZE];
    char response[MAX_MSG_SIZE];

    // 读取客户端发送的消息
    ssize_t bytesRead = read(client_socket, buffer, sizeof(buffer));
    if (bytesRead > 0) {
        // 解析客户端发送的消息
        if (strncmp(buffer, "客户端实现者20211312：", 17) == 0) {
            char *message = buffer + 17;
            int messageLength = strlen(message);

            // 倒序处理客户端发送的消息
            for (int i = 0; i < messageLength; i++) {
                response[i] = message[messageLength - i - 1];
            }
            response[messageLength] = '\0';

            // 获取客户端信息
            struct sockaddr_in client_address;
            socklen_t client_address_len = sizeof(client_address);
            getpeername(client_socket, (struct sockaddr *)&client_address, &client_address_len);
            char client_ip[INET_ADDRSTRLEN];
            inet_ntop(AF_INET, &(client_address.sin_addr), client_ip, INET_ADDRSTRLEN);
            int client_pid = getpid();
            int server_pid = getpid();

            // 构建响应消息
            sprintf(buffer, "客户端IP：%s\n客户端PID：%d\n服务器PID：%d\n服务器实现者学号：20211312\n客户端内容发送内容倒序：%s\n",
                    client_ip, client_pid, server_pid, response);

            // 向客户端发送响应
            write(client_socket, buffer, strlen(buffer));
        } else {
            // 不符合规则的消息，发送错误提示
            char *error = "错误：消息格式不正确\n";
            write(client_socket, error, strlen(error));
        }
    }

    // 关闭客户端连接
    close(client_socket);
}

int main() {
    int server_socket, client_socket;
    struct sockaddr_in server_address, client_address;
    socklen_t client_address_len = sizeof(client_address);

    // 创建服务器套接字
    server_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (server_socket == -1) {
        perror("创建套接字失败");
        exit(EXIT_FAILURE);
    }

    // 设置服务器地址
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = INADDR_ANY;
    server_address.sin_port = htons(PORT);

    // 绑定服务器套接字到指定地址和端口
    if (bind(server_socket, (struct sockaddr *)&server_address, sizeof(server_address)) < 0) {
        perror("绑定套接字失败");
        exit(EXIT_FAILURE);
    }

    // 监听客户端连接
    if (listen(server_socket, 5) < 0) {
        perror("监听失败");
        exit(EXIT_FAILURE);
    }

    printf("服务器已启动，监听端口：%d\n", PORT);

    // 处理客户端连接
    while (1) {
        // 接受客户端连接
        client_socket = accept(server_socket, (struct sockaddr *)&client_address, &client_address_len);
        if (client_socket < 0) {
            perror("接受连接失败");
            exit(EXIT_FAILURE);
        }

        // 创建子进程来处理客户端连接
        pid_t pid = fork();
        if (pid < 0) {
            perror("创建子进程失败");
            exit(EXIT_FAILURE);
        } else if (pid == 0) {
            // 在子进程中处理客户端连接
            close(server_socket);
            handle_client(client_socket);
            exit(EXIT_SUCCESS);
        } else {
            // 在父进程中继续监听客户端连接
            close(client_socket);
        }
    }

    // 关闭服务器套接字
    close(server_socket);

    return 0;
}