[Ethernet]网卡驱动 -- TCP通信传输文件

最近在搞网络驱动，在网上找到几个比较好的例程，自己又整理了下，代码贴在下面：
原帖地址已不可考，侵删

// server.c

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

#define SERVER_PORT 1234
#define LENGTH_OF_LISTEN_QUEUE 20
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512 

int main(int argc, char **argv)
{
    int listenfd, connfd;
    struct sockaddr_in servaddr;
    char buff[4096];
    int client_num = 0, n;

    if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
        exit(0);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(SERVER_PORT);
    
    int on = 1;
    setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

    if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) == -1)
    {
        printf("bind socket error: %s(errno: %d)\n", strerror(errno), errno);
        exit(0);
    }

    if (listen(listenfd, 10) == -1) // 最多连接10个用户
    {
        printf("listen socket error: %s(errno: %d)\n", strerror(errno), errno);
        exit(0);
    }

    printf("[Init]   %d client(s)!\n",client_num);

    if ((connfd = accept(listenfd, (struct sockaddr *)NULL, NULL)) == -1)
    {
        perror("accept");
        exit(1);
    }else
    {
        printf("[Connected] %d client(s)!\n",++client_num);
    }
    // Add While there if needed
    n = recv(connfd, buff, BUFFER_SIZE, 0);
    if(n > 0)
    {
        buff[n] = '\0';
        printf("Received: ");
        printf("%s\n", buff);
    }else if(n < 0)
    {
        perror("Server Recieve Data Failed:");
        exit(1);
    }else 
    {
        close(connfd);
        printf("[Closed]    %d client(s)!\n",--client_num);
        exit(1);
    }

    // 然后从buffer(缓冲区)拷贝到file_name中
    char file_name[FILE_NAME_MAX_SIZE+1];
    bzero(file_name, FILE_NAME_MAX_SIZE+1);
    strncpy(file_name, buff, strlen(buff)>FILE_NAME_MAX_SIZE?FILE_NAME_MAX_SIZE:strlen(buff));
    // printf("%s\n", file_name);

    // 打开文件并读取文件数据
    FILE *fp = fopen(file_name, "r");
    if(NULL == fp)
    {
        printf("File:%s Not Found\n", file_name);
    }
    else
    {
        bzero(buff, BUFFER_SIZE);
        int length = 0;
        // 每读取一段数据，便将其发送给客户端，循环直到文件读完为止
        while((length = fread(buff, sizeof(char), BUFFER_SIZE, fp)) > 0)
        {
            if(send(connfd, buff, length, 0) < 0)
            {
                printf("Send File:%s Failed./n", file_name);
                break;
            }
            bzero(buff, BUFFER_SIZE);
        }

        // 关闭文件
        fclose(fp);
        printf("File:%s Transfer Successful!\n", file_name);
    }
    // 关闭与客户端的连接
    close(connfd);

    close(listenfd);
}

// client.c

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

#define SERVER_PORT 1234
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512 

int main(int argc, char **argv)
{
    int client_socket_fd, n;
    char recvline[4096], sendline[4096];
    struct sockaddr_in servaddr;

    if (argc != 2)
    {
        printf("usage: ./client <ipaddress>\n");
        exit(0);
    }

    if ((client_socket_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
        exit(0);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(SERVER_PORT);
    if (inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0)
    {
        printf("inet_pton error for %s\n", argv[1]);
        exit(1);
    }

    if (connect(client_socket_fd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0)
    {
        printf("connect error: %s(errno: %d)\n", strerror(errno), errno);
        exit(1);
    }else
    {
        printf("[Init] connection established!\n");
    }

    // 输入文件名 并放到缓冲区buffer中等待发送
    char file_name[FILE_NAME_MAX_SIZE+1];
    bzero(file_name, FILE_NAME_MAX_SIZE+1);
    printf("Please Input File Name On Server:\t");
    scanf("%s", file_name); 

    char buffer[BUFFER_SIZE];
    bzero(buffer, BUFFER_SIZE);
    strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE?BUFFER_SIZE:strlen(file_name)); 

    // 向服务器发送buffer中的数据
    if(send(client_socket_fd, buffer, BUFFER_SIZE, 0) < 0)
    {
        perror("Send File Name Failed:");
        exit(1);
    }

    // 打开文件，准备写入
    FILE *fp = fopen(file_name, "w");
    if(NULL == fp)
    {
        printf("File:\t%s Can Not Open To Write\n", file_name);
        exit(1);
    } 

    // 从服务器接收数据到buffer中
    // 每接收一段数据，便将其写入文件中，循环直到文件接收完并写完为止
    bzero(buffer, BUFFER_SIZE);
    int length = 0;
    while((length = recv(client_socket_fd, buffer, BUFFER_SIZE, 0)) > 0)
    {
        if(fwrite(buffer, sizeof(char), length, fp) < length)
        {
            printf("File:\t%s Write Failed\n", file_name);
            break;
        }
        bzero(buffer, BUFFER_SIZE);
    }

    // 接收成功后，关闭文件，关闭socket
    printf("Receive File:\t%s From Server IP Successful!\n", file_name);
    close(fp);
    close(client_socket_fd);
    exit(0);
}