相关配置等请參看上一篇关于server端文章：http://blog.csdn.net/pingd/article/details/47805349
1.Client端源代码：
openssl_client.c
#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 <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 cert info:\n");
line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);
printf("Cert: %s\n", line);
free(line);
line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);
printf("Owner: %s\n", line);
free(line);
X509_free(cert);
} else
printf("No cert info\n");
} int main(int argc, char **argv)
{
int sockfd, len;
struct sockaddr_in dest;
char buffer[MAXBUF + 1];
SSL_CTX *ctx;
SSL *ssl; if (argc != 3)
{
printf("Usage:%s [server_ip] [server_port]\n",argv[0]);
exit(-1);
} /* SSL 库初始化，參看 ssl-server.c 代码 */
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"); /* 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);
} /* 接收对方发过来的消息，最多接收 MAXBUF 个字节 */
bzero(buffer, MAXBUF + 1);
/* 接收服务器来的消息 */
len = SSL_read(ssl, buffer, MAXBUF);
if (len > 0)
printf("recv message '%s' ok.total size:'%d'\n",
buffer, len);
else {
printf("recv message error!error code:'%d',error info:'%s'\n",
errno, strerror(errno));
goto finish;
}
bzero(buffer, MAXBUF + 1);
strcpy(buffer, "from client->server");
/* 发消息给服务器 */
len = SSL_write(ssl, buffer, strlen(buffer));
if (len < 0)
printf("send message '%s' error!error code:'%d',error info:'%s'\n",
buffer, errno, strerror(errno));
else
printf("send message '%s' ok,total size:'%d'\n",buffer, len); finish:
/* 关闭连接 */
SSL_shutdown(ssl);
SSL_free(ssl);
close(sockfd);
SSL_CTX_free(ctx);
return 0;
}
2.编译
gcc -o openssl_client openssl_client.c -Wall -lssl -lcrypto -L./openssl-1.0.2d/ -Wl,-rpath=./openssl-1.0.2d
3.执行
Usage:openssl_client [server_ip] [server_port]