2019-2020-1-20175332-实验五通讯协议设计

实验五 通讯协议设计-1

• 实验要求：

在Ubuntu中完成 http://www.cnblogs.com/rocedu/p/5087623.html 中的作业
提交运行结果截图

• 实验截图
  1、参考博客安装OpenSSL，并运行测试代码，输出结果为0，则安装成功
  测试代码如下：

    #include <stdio.h>
    #include <openssl/evp.h>
    int main(){
      OpenSSL_add_all_algorithms();
      return 0;
    }

截图：

2、socket编程
截图：

实验代码如下：
服务器端：

#include<stdio.h>  
#include<stdlib.h>  
#include<string.h>  
#include<errno.h>  
#include<sys/types.h>  
#include<sys/socket.h>  
#include<netinet/in.h>  
#define DEFAULT_PORT 8000  
#define MAXLINE 4096  
int main(int argc, char** argv)  
{  
    int    socket_fd, connect_fd;  
    struct sockaddr_in     servaddr;  
    char    buff[4096];  
    int     n;  
    if( (socket_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ){  
    printf("create socket error: %s(errno: %d)\n",strerror(errno),errno);  
    exit(0);  
    }  
    memset(&servaddr, 0, sizeof(servaddr));  
    servaddr.sin_family = AF_INET;  
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(DEFAULT_PORT);
    if( bind(socket_fd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1){  
    printf("bind socket error: %s(errno: %d)\n",strerror(errno),errno);  
    exit(0);  
    }  
    if( listen(socket_fd, 10) == -1){  
    printf("listen socket error: %s(errno: %d)\n",strerror(errno),errno);  
    exit(0);  
    }  
    printf("======waiting for client's request======\n");  
    while(1){  
        if( (connect_fd = accept(socket_fd, (struct sockaddr*)NULL, NULL)) == -1){  
        printf("accept socket error: %s(errno: %d)",strerror(errno),errno);  
        continue;  
    }  
 n = recv(connect_fd, buff, MAXLINE, 0);  
    if(!fork()){ 
        if(send(connect_fd, "Hello,you are connected!\n", 26,0) == -1)  
        perror("send error");  
        close(connect_fd);  
        exit(0);  
    }  
    buff[n] = '\0';  
    printf("recv msg from client: %s\n", buff);  
    close(connect_fd);  
    }  
    close(socket_fd);  
}

客户端：

#include<stdio.h>  
#include<stdlib.h>  
#include<string.h>  
#include<errno.h>  
#include<sys/types.h>  
#include<sys/socket.h>  
#include<netinet/in.h>  
#define MAXLINE 4096   
int main(int argc, char** argv)  
{  
    int    sockfd, n,rec_len;  
    char    recvline[4096], sendline[4096];  
    char    buf[MAXLINE];  
    struct sockaddr_in    servaddr;  
    if( argc != 2){  
    printf("usage: ./client <ipaddress>\n");  
    exit(0);  
    }  
    if( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){  
    printf("create socket error: %s(errno: %d)\n", strerror(errno),errno);  
    exit(0);  
    }  
    memset(&servaddr, 0, sizeof(servaddr));  
    servaddr.sin_family = AF_INET;  
    servaddr.sin_port = htons(8000);  
    if( inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0){  
    printf("inet_pton error for %s\n",argv[1]);  
    exit(0);  
    }  
    if( connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0){  
    printf("connect error: %s(errno: %d)\n",strerror(errno),errno);  
    exit(0);  
    }  
    printf("send msg to server: \n");  
    fgets(sendline, 4096, stdin);  
    if( send(sockfd, sendline, strlen(sendline), 0) < 0)  
    {  
    printf("send msg error: %s(errno: %d)\n", strerror(errno), errno);  
    exit(0);  
    }  
    if((rec_len = recv(sockfd, buf, MAXLINE,0)) == -1) {  
       perror("recv error");  
       exit(1);  
    }  
    buf[rec_len]  = '\0';  
    printf("Received : %s ",buf);  
    close(sockfd);  
    exit(0);  
}

实验五 通讯协议设计-2

• 实验要求：

在Ubuntu中实现对实验二中的“wc服务器”通过混合密码系统进行防护
提交测试截图
实验代码如下：
服务器：

#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 <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/evp.h>


#define MAXBUF 1024

int main(int argc, char **argv)
{
    int sockfd, new_fd;
    socklen_t len;
    struct sockaddr_in my_addr, their_addr;
    unsigned int myport, lisnum;
    char buf[MAXBUF + 1];
    SSL_CTX *ctx;
if (argv[1])
        myport = atoi(argv[1]);
    else
        myport = 7838;

if (argv[2])
        lisnum = atoi(argv[2]);
    else
        lisnum = 2;

SSL_library_init();
    OpenSSL_add_all_algorithms();
    SSL_load_error_strings();
    ctx = SSL_CTX_new(SSLv23_server_method());
    if (ctx == NULL) {
        ERR_print_errors_fp(stdout);
        exit(1);
    }
    if (SSL_CTX_use_certificate_file(ctx, argv[3], SSL_FILETYPE_PEM) <= 0) {
        ERR_print_errors_fp(stdout);
        exit(1);
    }
    if (SSL_CTX_use_PrivateKey_file(ctx, argv[4], SSL_FILETYPE_PEM) <= 0){
        ERR_print_errors_fp(stdout);
        exit(1);
    }
    if (!SSL_CTX_check_private_key(ctx)) {
        ERR_print_errors_fp(stdout);
        exit(1);
    }
    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);
    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);
        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);
        ssl = SSL_new(ctx);
        SSL_set_fd(ssl, new_fd);
        if (SSL_accept(ssl) == -1) {
            perror("accept");
            close(new_fd);
            break;
        }
        bzero(buf, MAXBUF + 1);
        strcpy(buf, "server->client");
        len = SSL_write(ssl, buf, strlen(buf));
        if (len <= 0) {
            printf
                ("消息'%s'发送失败！错误代码是%d，错误信息是'%s'\n",
                 buf, errno, strerror(errno));
            goto finish;
        } else
            printf("消息'%s'发送成功，共发送了%d个字节！\n",
                   buf, len);
        bzero(buf, MAXBUF + 1);
        len = SSL_read(ssl, buf, MAXBUF);
        if (len > 0)
            printf("接收消息成功:'%s'，共%d个字节的数据\n",
                   buf, 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));
      finish:
        SSL_shutdown(ssl);
        SSL_free(ssl);
        close(new_fd);
    }
    close(sockfd);
    SSL_CTX_free(ctx);
    return 0;
}

客户端：

#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>
#include <openssl/evp.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");  
}  
  
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！正确用法如下：\n\t\t%s IP地址 端口\n\t比如:\t%s 127.0.0.1 80\n此程序用来从某个"  
             "IP 地址的服务器某个端口接收最多 MAXBUF 个字节的消息",  
             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");  
    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");  
  
    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);  
    }  
  
    bzero(buffer, MAXBUF + 1);  
    len = SSL_read(ssl, buffer, MAXBUF);  
    if (len > 0)  
        printf("接收消息成功:'%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);  
    strcpy(buffer, "from client->server");  
    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:  
    SSL_shutdown(ssl);  
    SSL_free(ssl);  
    close(sockfd);  
    SSL_CTX_free(ctx);  
    return 0;  
}

问题:
openssl: error while loading shared libraries: libssl.so.3: cannot open shared object file: No such file or directory
解决方法
1 下载1.0版本------------无法解决问题
2 经过百度找到类似问题：加载共享库时出错：libssl.so.1.1:无法打开共享对象文件：没有这样的文件或目录
解决办法：
使用ln命令构建文件件连接
ln -s /usr/local/lib/libssl.so.1.1 /usr/lib/libssl.so.1.1
ln -s /usr/local/lib/libcrypto.so.1.1 /usr/lib/libcrypto.so.1.1
类比
将命令改为：
ln -s /usr/local/lib/libssl.so.3 /usr/lib/libssl.so.3
ln -s /usr/local/lib/libcrypto.so.3 /usr/lib/libcrypto.so.3
实验截图：

实验结果