基于c语言的网络编程tcp透传，功能服务器能保存透传的信息记客户端的信息的代码

在C语言中，基于TCP的网络编程通常会涉及到套接字编程（socket programming）。透传（Transparent Transfer）通常是指在网络通信中数据不做修改地从发送端直接传输到接收端。下面是一个简单的示例，展示了如何创建一个功能服务器，它接收客户端连接，并保存客户端信息及接收到的数据：

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

#define MAX_CLIENTS 5
#define BUFFER_SIZE 1024

struct client_info {
    int socket;
    char address[INET_ADDRSTRLEN];
};

void handle_client(int server_socket, struct sockaddr_in client_addr) {
    char buffer[BUFFER_SIZE];
    int bytes_received;

    // 创建一个新的套接字用于与客户端通信
    int client_socket = accept(server_socket, (struct sockaddr*)&client_addr, NULL);
    
    if (client_socket == -1) {
        perror("Error accepting connection");
        return;
    }

    // 读取并保存客户端信息
    bytes_received = recv(client_socket, buffer, sizeof(buffer), 0);
    buffer[bytes_received] = '\0';
    printf("Received from %s: %s\n", inet_ntoa(client_addr.sin_addr), buffer);

    // 开始透传数据
    while ((bytes_received = recv(client_socket, buffer, BUFFER_SIZE, 0)) > 0) {
        send(client_socket, buffer, bytes_received, 0);  // 直接转发给客户端
        printf("Forwarded to client: %s\n", buffer);
    }
    
    if (bytes_received == 0) {
        printf("Client closed the connection.\n");
    } else {
        perror("Error reading from client");
    }

    close(client_socket);
}

int main() {
    int server_socket, port;
    struct addrinfo hints, *res;

    // 设置服务器地址和端口
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC;   // 使用IPv4或IPv6
    hints.ai_socktype = SOCK_STREAM; // TCP连接
    hints.ai_flags = AI_PASSIVE;    // 主动监听

    if (getaddrinfo(NULL, "8080", &hints, &res) != 0) {
        perror("Error getting address info");
        exit(1);
    }

    server_socket = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
    if (server_socket == -1) {
        perror("Error creating socket");
        freeaddrinfo(res);
        exit(1);
    }

    if (bind(server_socket, res->ai_addr, res->ai_addrlen) == -1) {
        perror("Error binding socket");
        close(server_socket);
        freeaddrinfo(res);
        exit(1);
    }

    listen(server_socket, MAX_CLIENTS);

    printf("Server listening on port %d...\n", ntohs(res->ai_port));

    freeaddrinfo(res);

    // 接受并处理客户端连接
    while (true) {
        struct sockaddr_in client_addr;
        socklen_t client_len = sizeof(client_addr);
        connfd = accept(server_socket, (struct sockaddr *)&client_addr, &client_len);
        handle_client(connfd, client_addr);
    }

    close(server_socket);
    return 0;
}

在这个示例中，服务器会在指定端口上监听连接请求，当有新客户端连接时，会创建一个新的套接字并与之通信。数据从客户端到达服务器后，服务器会简单地转发回去，实现了基本的TCP透传。