利用OpenSSL建立SSL安全通信(C/S)（二）

/***************************************************************************************

*SSL/TLS服务端程序WIN32版(以demos/server.cpp为基础)

*需要用到动态连接库libeay32.dll,ssleay.dll,

*同时在setting中加入ws2_32.lib libeay32.lib ssleay32.lib,

*以上库文件在编译openssl后可在out32dll目录下找到,

*所需证书文件请参照<<利用Openssl生成证书文件>>自行生成

***************************************************************************************/

#include <stdio.h>

#include <stdlib.h>

#include <memory.h>

#include <errno.h>

#include <sys/types.h>

#include <winsock2.h>

#include "openssl/rsa.h"

#include "openssl/crypto.h"

#include "openssl/x509.h"

#include "openssl/pem.h"

#include "openssl/ssl.h"

#include "openssl/err.h"

/*所有需要的参数信息都在此处以#define的形式提供*/

#define CERTF "server.crt" /*服务端的证书(需经CA签名)*/

#define KEYF "server.key" /*服务端的私钥(建议加密存储)*/

#define CACERT "ca.crt" /*CA 的证书*/

#define PORT 1111 /*准备绑定的端口*/

#define CHK_NULL(x) if ((x)==NULL) { exit (1); }

#define CHK_ERR(err,s) if ((err)==-1) { perror(s); exit(1); }

#define CHK_SSL(err) if ((err)==-1) { ERR_print_errors_fp(stderr); exit(2); }

int main ()

{

int err;

int listen_sd;

int sd;

struct sockaddr_in sa_serv;

struct sockaddr_in sa_cli;

int client_len;

SSL_CTX* ctx;

SSL* ssl;

X509* client_cert;

char* str;

char buf [4096];

SSL_METHOD *meth;

WSADATA wsaData;

if(WSAStartup(MAKEWORD(2,2),&wsaData) != 0)

{

printf("WSAStartup()fail:%dn",GetLastError());

return -1;

}

SSL_load_error_strings(); /*为打印调试信息作准备*/

OpenSSL_add_ssl_algorithms(); /*初始化,加载算法*/

meth = TLSv1_server_method(); /*采用什么协议(SSLv2/SSLv3/TLSv1)在此指定*/

ctx = SSL_CTX_new (meth);

CHK_NULL(ctx);

SSL_CTX_set_verify(ctx,SSL_VERIFY_PEER,NULL); /*验证与否*/

SSL_CTX_load_verify_locations(ctx,CACERT,NULL); /*若验证,则放置CA证书*/

//加载自己的证书文件

if(SSL_CTX_use_certificate_file(ctx,CERTF,SSL_FILETYPE_PEM) <= 0)

{

ERR_print_errors_fp(stderr);

exit(3);

}

//加载自己的密钥文件

if(SSL_CTX_use_PrivateKey_file(ctx, KEYF, SSL_FILETYPE_PEM) <= 0)

{

ERR_print_errors_fp(stderr);

exit(4);

}

//验证

if(!SSL_CTX_check_private_key(ctx))

{

printf("Private key does not match the certificate public key/n");

exit(5);

}

//选择安全通信协议

SSL_CTX_set_cipher_list(ctx,"RC4-MD5");

/*开始正常的TCP socket过程.................................*/

printf("Begin TCP socket.../n");

listen_sd = socket (AF_INET, SOCK_STREAM, 0);

CHK_ERR(listen_sd, "socket");

memset (&sa_serv, '/0', sizeof(sa_serv));

sa_serv.sin_family = AF_INET;

sa_serv.sin_addr.s_addr = INADDR_ANY;

sa_serv.sin_port = htons (PORT);

err = bind(listen_sd, (struct sockaddr*) &sa_serv,

sizeof (sa_serv));

CHK_ERR(err, "bind");

/*接受TCP链接*/

err = listen (listen_sd, 5);

CHK_ERR(err, "listen");

client_len = sizeof(sa_cli);

sd = accept (listen_sd, (struct sockaddr*) &sa_cli, &client_len);

CHK_ERR(sd, "accept");

closesocket (listen_sd);

printf ("Connection from %lx, port %x/n",

sa_cli.sin_addr.s_addr, sa_cli.sin_port);

/*TCP连接已建立,进行服务端的SSL过程...................... */

printf("Begin server side SSL/n");

ssl = SSL_new (ctx);

CHK_NULL(ssl);

SSL_set_fd (ssl, sd);

err = SSL_accept (ssl);

printf("SSL_accept finishedn");

CHK_SSL(err);

/*打印所有加密算法的信息(可选)*/

printf ("SSL connection using %s/n", SSL_get_cipher (ssl));

/*得到客户端的证书并打印些信息(可选) */

client_cert = SSL_get_peer_certificate (ssl);

if(client_cert != NULL)

{

printf ("Client certificate:/n");

str = X509_NAME_oneline(X509_get_subject_name (client_cert), 0, 0);

CHK_NULL(str);

printf ("t subject: %s/n", str);

free (str);

str = X509_NAME_oneline(X509_get_issuer_name (client_cert), 0, 0);

CHK_NULL(str);

printf ("t issuer: %s/n", str);

free (str);

X509_free (client_cert);/*如不需要,则将证书释放 */

}

else

{

printf ("Client does not have certificate./n");

}

/* 数据交换开始,用SSL_write,SSL_read代替write,read */

err = SSL_read (ssl, buf, sizeof(buf) - 1);

CHK_SSL(err);

buf[err] = '/0';

printf ("Got %d chars:'%s'/n", err, buf);

err = SSL_write (ssl, "I hear you.", strlen("I hear you."));

CHK_SSL(err);

/* 收尾工作*/

shutdown (sd,2);

SSL_free (ssl);

SSL_CTX_free (ctx);

return 0;

}

//OpenSSL库的下载,请查看<<OpenSSL库的编译与安装>>;

//利用OpenSSL库生成证书文件,请查看<<利用OpenSSL生成证书文件>>.

//常用API<<利用OpenSSL编写SSL通信程序时常使用的API>>.