20.8 OpenSSL 套接字SSL传输文件

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20.8 OpenSSL 套接字SSL传输文件

有了上面的基础那么传输文件的实现就变得简单了，在传输时通常我们需要打开文件，并每次读入1024个字节的数据包，通过SSL加密传输即可，此处的文件传输功能在原生套接字章节中也进行过详细讲解，此处我们还是使用原来的密钥对，实现一个服务端等待客户端上传，当客户端连接到服务端后则开始传输文件，服务端接收文件的功能。

服务端代码部分，此处我们只需要实现一个DownloadFile函数，该函数接收一个SSL套接字，与保存文件路径即可，其他部分同上。

#include <WinSock2.h>
#include <iostream>
#include <string.h>
#include <errno.h>
#include <stdlib.h>#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <openssl/pem.h>
#include <openssl/crypto.h>extern "C"
{
#include <openssl/applink.c>
}#pragma comment(lib, "WS2_32.lib")
#pragma comment(lib,"libssl.lib")
#pragma comment(lib,"libcrypto.lib")#define MAXBUF 1024// 从路径中获取当前文件名
char* GetFileName(char* Path)
{if (strchr(Path, '\\')){char ch = '\\';char* ref = strrchr(Path, ch) + 1;return ref;}else{char ch = '/';char* ref = strrchr(Path, ch) + 1;return ref;}
}// 下载文件到当前目录
// 传入套接字句柄,以及放置根目录
void DownloadFile(SSL* ptr, const char* RootPath)
{int FileSize = 0;char FilePath[1024] = { 0 };char buffer[1024] = { 0 };// 接收文件长度SSL_read(ptr, &FileSize, 4);// 接收文件路径SSL_read(ptr, FilePath, 1024);// 获取到文件名char* FileName = GetFileName(FilePath);// 拼接路径char sz[1024] = { 0 };strcpy(sz, RootPath);strcat(sz, FileName);std::cout << sz << std::endl;// 保存文件到当前目录FILE* pointer = fopen(sz, "wb");if (pointer != NULL){DWORD length = 0;DWORD total_length = 0;// 循环接收字节数据,每次接收1024字节while ((length = SSL_read(ptr, buffer, 1024)) > 0){// 写出文件并判断是否写出成功if (fwrite(buffer, sizeof(char), length, pointer) < length){break;}// 每次累加递增total_length += length;memset(buffer, 0, 1024);// 判断文件长度是否全部接收完毕if (total_length >= FileSize){std::cout << "[传输完成] " << total_length << std::endl;fclose(pointer);return;}}fclose(pointer);}
}int main(int argc, char** argv)
{SOCKET sockfd, new_fd;struct sockaddr_in socket_ptr, their_addr;char buf[MAXBUF + 1];SSL_CTX* ctx;SSL_library_init();OpenSSL_add_all_algorithms();SSL_load_error_strings();ctx = SSL_CTX_new(SSLv23_server_method());if (ctx == NULL){return 0;}if (SSL_CTX_use_certificate_file(ctx, "d://cacert.pem", SSL_FILETYPE_PEM) <= 0){return 0;}if (SSL_CTX_use_PrivateKey_file(ctx, "d://privkey.pem", SSL_FILETYPE_PEM) <= 0){return 0;}if (!SSL_CTX_check_private_key(ctx)){return 0;}WSADATA wsaData;WSAStartup(MAKEWORD(2, 2), &wsaData);if (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2){WSACleanup();return 0;}if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){return 0;}socket_ptr.sin_family = AF_INET;socket_ptr.sin_addr.s_addr = inet_addr("127.0.0.1");socket_ptr.sin_port = htons(9999);if (bind(sockfd, (struct sockaddr*)&socket_ptr, sizeof(struct sockaddr)) == -1){return 0;}if (listen(sockfd, 10) == -1){return 0;}while (1){SSL* ssl;int len = sizeof(struct sockaddr);if ((new_fd = accept(sockfd, (struct sockaddr*)&their_addr, &len)) != -1){printf("客户端地址: %s --> 端口: %d --> 套接字: %d \n", inet_ntoa(their_addr.sin_addr), ntohs(their_addr.sin_port), new_fd);}ssl = SSL_new(ctx);SSL_set_fd(ssl, new_fd);if (SSL_accept(ssl) == -1){closesocket(new_fd);break;}// 调用下载文件函数DownloadFile(ssl, "d://lyshark/");finish:SSL_shutdown(ssl);SSL_free(ssl);closesocket(new_fd);}closesocket(sockfd);WSACleanup();SSL_CTX_free(ctx);system("pause");return 0;
}

客户端部分，同样代码中只需要实现一个UploadFile函数，该函数用于发送本地文件到远程，其他部分同上。

#include <WinSock2.h>
#include <iostream>
#include <string.h>
#include <errno.h>
#include <stdlib.h>#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <openssl/pem.h>
#include <openssl/crypto.h>extern "C"
{
#include <openssl/applink.c>
}#pragma comment(lib, "WS2_32.lib")
#pragma comment(lib,"libssl.lib")
#pragma comment(lib,"libcrypto.lib")#define MAXBUF 1024// 获取文件大小
int GetFileSize(std::string FileName)
{FILE* pointer = NULL;pointer = fopen(FileName.c_str(), "rb");if (pointer != NULL){fseek(pointer, 0, SEEK_END);int size = ftell(pointer);fclose(pointer);return size;}return 0;
}// 上传文件,传入socket套接字句柄,需要发送的文件路径
void UploadFile(SSL* ptr, const char* FilePath)
{int FileSize = GetFileSize(FilePath);char buffer[1024] = { 0 };// 发送文件长度SSL_write(ptr, &FileSize, 4);// 发送完整文件路径SSL_write(ptr, FilePath, strlen(FilePath));FILE* pointer = fopen(FilePath, "rb");if (pointer != NULL){int length = 0;DWORD total_length = 0;while ((length = fread(buffer, sizeof(char), 1024, pointer)) > 0){SSL_write(ptr, buffer, length);memset(buffer, 0, 1024);}}
}int main(int argc, char** argv)
{int sockfd, len;struct sockaddr_in dest;char buffer[MAXBUF + 1] = { 0 };SSL_CTX* ctx;SSL* ssl;SSL_library_init();OpenSSL_add_all_algorithms();SSL_load_error_strings();ctx = SSL_CTX_new(SSLv23_client_method());if (ctx == NULL){WSACleanup();return 0;}WSADATA wsaData;WSAStartup(MAKEWORD(2, 2), &wsaData);if (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2){WSACleanup();return 0;}if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){WSACleanup();return 0;}dest.sin_family = AF_INET;dest.sin_addr.s_addr = inet_addr("127.0.0.1");dest.sin_port = htons(9999);if (connect(sockfd, (struct sockaddr*)&dest, sizeof(dest)) != 0){WSACleanup();return 0;}ssl = SSL_new(ctx);SSL_set_fd(ssl, sockfd);if (SSL_connect(ssl) != -1){printf("SSL 连接类型: %s \n", SSL_get_cipher(ssl));}// 发送文件UploadFile(ssl, "d://lyshark.exe");finish:SSL_shutdown(ssl);SSL_free(ssl);closesocket(sockfd);SSL_CTX_free(ctx);system("pause");return 0;
}

读者可自行编译这段代码，并首先启动服务端等待传输，接着打开客户端，此时客户端中的d://lyshark.exe将被传输到服务端的特定目录下，如下图所示；