ssl通信c实现

/*File:client.c
*Auth:sjin
*Date：2014-03-11
*
*/

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <resolv.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <openssl/ssl.h>
#include <openssl/err.h>

#define MAXBUF 1024

void ShowCerts(SSL * ssl)
{
X509 *cert;
char *line;

cert = SSL_get_peer_certificate(ssl);
if (cert != NULL) {
printf("Digital certificate information:\n");
line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);
printf("Certificate: %s\n", line);
free(line);
line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);
printf("Issuer: %s\n", line);
free(line);
X509_free(cert);
}
else
printf("No certificate information！\n");
}

int main(int argc, char **argv)
{
int i,j,sockfd, len, fd, size;
char fileName[50],sendFN[20];
struct sockaddr_in dest;
char buffer[MAXBUF + 1];
SSL_CTX *ctx;
SSL *ssl;

if (argc != 3)
{
printf("Parameter format error! Correct usage is as follows：\n\t\t%s IP Port\n\tSuch as:\t%s 127.0.0.1 80\n", argv[0], argv[0]); exit(0);
}

/* SSL 库初始化 */
SSL_library_init();
OpenSSL_add_all_algorithms();
SSL_load_error_strings();
ctx = SSL_CTX_new(SSLv23_client_method());
if (ctx == NULL)
{
ERR_print_errors_fp(stdout);
exit(1);
}

/* 创建一个 socket 用于 tcp 通信 */
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
perror("Socket");
exit(errno);
}
printf("socket created\n");

/* 初始化服务器端（对方）的地址和端口信息 */
bzero(&dest, sizeof(dest));
dest.sin_family = AF_INET;
dest.sin_port = htons(atoi(argv[2]));
if (inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr) == 0)
{
perror(argv[1]);
exit(errno);
}
printf("address created\n");

/* 连接服务器 */
if (connect(sockfd, (struct sockaddr *) &dest, sizeof(dest)) != 0)
{
perror("Connect ");
exit(errno);
}
printf("server connected\n\n");

/* 基于 ctx 产生一个新的 SSL */
ssl = SSL_new(ctx);
SSL_set_fd(ssl, sockfd);
/* 建立 SSL 连接 */
if (SSL_connect(ssl) == -1)
ERR_print_errors_fp(stderr);
else
{
printf("Connected with %s encryption\n", SSL_get_cipher(ssl));
ShowCerts(ssl);
}

/* 接收用户输入的文件名，并打开文件 */
printf("\nPlease input the filename of you want to load :\n>");
scanf("%s",fileName);
if((fd = open(fileName,O_RDONLY,0666))<0)
{
perror("open:");
exit(1);
}

/* 将用户输入的文件名，去掉路径信息后，发给服务器 */
for(i=0;i<=strlen(fileName);i++)
{
if(fileName[i]=='/')
{
j=0;
continue;
}
else {sendFN[j]=fileName[i];++j;}
}
len = SSL_write(ssl, sendFN, strlen(sendFN));
if (len < 0)
printf("'%s'message Send failure ！Error code is %d，Error messages are '%s'\n", buffer, errno, strerror(errno));

/* 循环发送文件内容到服务器 */
bzero(buffer, MAXBUF + 1);
while((size=read(fd,buffer,1024)))
{
if(size<0)
{
perror("read:");
exit(1);
}
else
{
len = SSL_write(ssl, buffer, size);
if (len < 0)
printf("'%s'message Send failure ！Error code is %d，Error messages are '%s'\n", buffer, errno, strerror(errno));
}
bzero(buffer, MAXBUF + 1);
}
printf("Send complete !\n");

/* 关闭连接 */
close(fd);
SSL_shutdown(ssl);
SSL_free(ssl);
close(sockfd);
SSL_CTX_free(ctx);
return 0;
}

/*File:server.c
*Auth:sjin
*Date：2014-03-11
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <openssl/ssl.h>
#include <openssl/err.h>

#define MAXBUF 1024

int main(int argc, char **argv)
{
int sockfd, new_fd, fd;
socklen_t len;
struct sockaddr_in my_addr, their_addr;
unsigned int myport, lisnum;
char buf[MAXBUF + 1];
char new_fileName[50]="/newfile/";
SSL_CTX *ctx;
mode_t mode;
char pwd[100];
char* temp;

/* 在根目录下创建一个newfile文件夹 */
mkdir("/newfile",mode);

if (argv[1])
myport = atoi(argv[1]);
else
{
myport = 7838;
argv[2]=argv[3]=NULL;
}

if (argv[2])
lisnum = atoi(argv[2]);
else
{
lisnum = 2;
argv[3]=NULL;
}

/* SSL 库初始化 */
SSL_library_init();
/* 载入所有 SSL 算法 */
OpenSSL_add_all_algorithms();
/* 载入所有 SSL 错误消息 */
SSL_load_error_strings();
/* 以 SSL V2 和 V3 标准兼容方式产生一个 SSL_CTX ，即 SSL Content Text */
ctx = SSL_CTX_new(SSLv23_server_method());
/* 也可以用 SSLv2_server_method() 或 SSLv3_server_method() 单独表示 V2 或 V3标准 */
if (ctx == NULL)
{
ERR_print_errors_fp(stdout);
exit(1);
}
/* 载入用户的数字证书， 此证书用来发送给客户端。 证书里包含有公钥 */
getcwd(pwd,100);
if(strlen(pwd)==1)
pwd[0]='\0';
if (SSL_CTX_use_certificate_file(ctx, temp=strcat(pwd,"/cacert.pem"), SSL_FILETYPE_PEM) <= 0)
{
ERR_print_errors_fp(stdout);
exit(1);
}
/* 载入用户私钥 */
getcwd(pwd,100);
if(strlen(pwd)==1)
pwd[0]='\0';
if (SSL_CTX_use_PrivateKey_file(ctx, temp=strcat(pwd,"/privkey.pem"), SSL_FILETYPE_PEM) <= 0)
{
ERR_print_errors_fp(stdout);
exit(1);
}
/* 检查用户私钥是否正确 */
if (!SSL_CTX_check_private_key(ctx))
{
ERR_print_errors_fp(stdout);
exit(1);
}

/* 开启一个 socket 监听 */
if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1)
{
perror("socket");
exit(1);
}
else
printf("socket created\n");

bzero(&my_addr, sizeof(my_addr));
my_addr.sin_family = PF_INET;
my_addr.sin_port = htons(myport);
if (argv[3])
my_addr.sin_addr.s_addr = inet_addr(argv[3]);
else
my_addr.sin_addr.s_addr = INADDR_ANY;

if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr)) == -1)
{
perror("bind");
exit(1);
}
else
printf("binded\n");

if (listen(sockfd, lisnum) == -1)
{
perror("listen");
exit(1);
}
else
printf("begin listen\n");

while (1)
{
SSL *ssl;
len = sizeof(struct sockaddr);
/* 等待客户端连上来 */
if ((new_fd = accept(sockfd, (struct sockaddr *) &their_addr, &len)) == -1)
{
perror("accept");
exit(errno);
}
else
printf("server: got connection from %s, port %d, socket %d\n", inet_ntoa(their_addr.sin_addr), ntohs(their_addr.sin_port), new_fd);

/* 基于 ctx 产生一个新的 SSL */
ssl = SSL_new(ctx);
/* 将连接用户的 socket 加入到 SSL */
SSL_set_fd(ssl, new_fd);
/* 建立 SSL 连接 */
if (SSL_accept(ssl) == -1)
{
perror("accept");
close(new_fd);
break;
}

/* 接受客户端所传文件的文件名并在特定目录创建空文件 */
bzero(buf, MAXBUF + 1);
bzero(new_fileName+9, 42);
len = SSL_read(ssl, buf, MAXBUF);
if(len == 0)
printf("Receive Complete !\n");
else if(len < 0)
printf("Failure to receive message ! Error code is %d，Error messages are '%s'\n", errno, strerror(errno));
if((fd = open(strcat(new_fileName,buf),O_CREAT | O_TRUNC | O_RDWR,0666))<0)
{
perror("open:");
exit(1);
}

/* 接收客户端的数据并写入文件 */
while(1)
{
bzero(buf, MAXBUF + 1);
len = SSL_read(ssl, buf, MAXBUF);
if(len == 0)
{
printf("Receive Complete !\n");
break;
}
else if(len < 0)
{
printf("Failure to receive message ! Error code is %d，Error messages are '%s'\n", errno, strerror(errno));
exit(1);
}
if(write(fd,buf,len)<0)
{
perror("write:");
exit(1);
}
}

/* 关闭文件 */
close(fd);
/* 关闭 SSL 连接 */
SSL_shutdown(ssl);
/* 释放 SSL */
SSL_free(ssl);
/* 关闭 socket */
close(new_fd);
}

/* 关闭监听的 socket */
close(sockfd);
/* 释放 CTX */
SSL_CTX_free(ctx);
return 0;
}