ssl-client.c

linux下的ssl客户端和服务器端源码

#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("数字证书信息:\n");
        line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);
        printf("证书: %s\n", line);
        free(line);
        line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);
        printf("颁发者: %s\n", line);
        free(line);
        X509_free(cert);
    } else
        printf("无证书信息！\n");
}
/************关于本文档********************************************
*filename: ssl-client.c
*purpose: 演示利用 OpenSSL 库进行基于 IP层的 SSL 加密通讯的方法，这是客户端例子
*wrote by: yuankang([e-mail])
*date time:2007-12-12
*********************************************************************/
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("参数格式错误！正确用法：IP Port\n");
        exit(0);
    }

    /* SSL 库初始化，参看 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 */
    printf("socket creating......  \t\t");
    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 */
    printf("address creating...... \t\t");
    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 */
    printf("server connecting......\t\t");
    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("接收到来自服务器的消息:'%s'，共%d个字节的数据。\n",
               buffer, len);
    else {
        printf
            ("消息接收失败！错误代码是%d，错误信息是'%s'\n",
             errno, strerror(errno));
        goto finish;
    }
    bzero(buffer, MAXBUF + 1);
    printf("输入要发送服务器的消息:");
    scanf("%[^\n]",buffer);
    /* 发消息给服务器 */
    len = SSL_write(ssl, buffer, strlen(buffer));
    if (len < 0)
        printf
            ("消息'%s'发送失败！错误代码是%d，错误信息是'%s'\n",
             buffer, errno, strerror(errno));
    else
        printf("消息'%s'发送成功，共发送了%d个字节！\n",
               buffer, len);

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