socket测试

echo_server

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

#define PORT 7406

void handle_client(int client_socket, char *student_id) {
    char buffer[1024];
    ssize_t bytes_received;

    // Receive data from the client
    bytes_received = recv(client_socket, buffer, sizeof(buffer), 0);
    if (bytes_received < 0) {
        perror("Error receiving data from client");
        close(client_socket);
        exit(EXIT_FAILURE);
    }

    buffer[bytes_received] = '\0';

    // Check if the received data follows the specified format
    if (sscanf(buffer, "%*[^:]:%*[^:]:%*d:%*d:%s", student_id) != 1) {
        fprintf(stderr, "Error: Invalid data format received from client.\n");
        close(client_socket);
        exit(EXIT_FAILURE);
    }

    // Reverse the received data
    int len = strlen(buffer);
    for (int i = 0; i < len / 2; i++) {
        char temp = buffer[i];
        buffer[i] = buffer[len - i - 1];
        buffer[len - i - 1] = temp;
    }

    // Send the reversed data back to the client
    ssize_t bytes_sent = send(client_socket, buffer, strlen(buffer), 0);
    if (bytes_sent < 0) {
        perror("Error sending data to client");
    }

    // Close the client socket
    close(client_socket);
    exit(EXIT_SUCCESS);
}

int main() {
    int server_socket, client_socket;
    struct sockaddr_in server_addr, client_addr;
    socklen_t client_addr_len = sizeof(client_addr);
    char student_id[9];

    // Create socket
    server_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (server_socket < 0) {
        perror("Error creating socket");
        exit(EXIT_FAILURE);
    }

    // Configure server address
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_port = htons(PORT);

    // Bind socket
    if (bind(server_socket, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("Error binding socket");
        close(server_socket);
        exit(EXIT_FAILURE);
    }

    // Listen for incoming connections
    if (listen(server_socket, 5) < 0) {
        perror("Error listening for connections");
        close(server_socket);
        exit(EXIT_FAILURE);
    }

    while (1) {
        // Accept connection from client
        client_socket = accept(server_socket, (struct sockaddr *)&client_addr, &client_addr_len);
        if (client_socket < 0) {
            perror("Error accepting connection");
            continue;
        }

        // Fork a new process to handle the client
        pid_t pid = fork();
        if (pid < 0) {
            perror("Error forking process");
            close(client_socket);
            continue;
        } else if (pid == 0) {
            // Child process handles the client
            close(server_socket);
            handle_client(client_socket, student_id);
        } else {
            // Parent process continues to accept new connections
            close(client_socket);
        }
    }

    // Close the server socket
    close(server_socket);

    return 0;
}

echo_client

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

#define PORT 7406

int main() {
    int client_socket;
    struct sockaddr_in server_addr;
    char student_id[9] = "YOUR_ID"; // Replace with your 8-digit student ID

    // Create socket
    client_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (client_socket < 0) {
        perror("Error creating socket");
        exit(EXIT_FAILURE);
    }

    // Configure server address
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1"); // Assuming server is running locally

    // Connect to the server
    if (connect(client_socket, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("Error connecting to server");
        close(client_socket);
        exit(EXIT_FAILURE);
    }

    // Send data to the server
    char message[1024];
    snprintf(message, sizeof(message), "客户端实现者%s:消息", student_id);

    ssize_t bytes_sent = send(client_socket, message, strlen(message), 0);
    if (bytes_sent < 0) {
        perror("Error sending data to server");
    }

    // Receive and print the response from the server
    char buffer[1024];
    ssize_t bytes_received = recv(client_socket, buffer, sizeof(buffer), 0);
    if (bytes_received < 0) {
        perror("Error receiving data from server");
    } else {
        buffer[bytes_received] = '\0';
        printf("Server Response:\n%s\n", buffer);
    }

    // Close the client socket
    close(client_socket);

    return 0;
}