基于C语言实现的TCP服务器的流程分析

int socket(int domain, int type, int protocol);

int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen);

int listen(int sockfd, int backlog);

int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen);

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.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};
    const char *hello = "Hello from server";
    // 创建套接字
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("Socket failed");
        exit(EXIT_FAILURE);
    }
    // 绑定IP和端口
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);
    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("Bind failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }
    // 监听连接请求
    if (listen(server_fd, 3) < 0) {
        perror("Listen failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }
    printf("Waiting for connections...\n");
    // 接受客户端连接
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen)) < 0) {
        perror("Accept failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }
    // 接收数据
    int valread = read(new_socket, buffer, BUFFER_SIZE);
    printf("Received: %s\n", buffer);
    // 发送数据
    send(new_socket, hello, strlen(hello), 0);
    printf("Hello message sent\n");
    // 关闭套接字
    close(new_socket);
    close(server_fd);
    return 0;
}

gcc -o tcp_server tcp_server.c

./tcp_server

telnet 127.0.0.1 8080