2018-2019-1 20165307 20165327 20165332 实验五通讯协议设计

Linux下OpenSSL的安装与使用

1.两人一组
2.基于Socket实现TCP通信，一人实现服务器，一人实现客户端
3.研究OpenSSL算法，测试对称算法中的AES，非对称算法中的RSA，Hash算法中的MD5
4.选用合适的算法，基于混合密码系统实现对TCP通信进行机密性、完整性保护。

实验步骤

在OpenSSL下载地址下载OpenSSL
解压OpenSSL源代码tar xzvf openssl-1.1.0j.tar.gz
进入源代码目录后

$ ./config
$ make
$ make test
$ make install

编写测试代码 test_openssl.c

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

编译和执行
结果打印0则表示安装成功

实现TCP通信

server.c：

#include<stdlib.h>

#include<pthread.h>

#include<sys/socket.h>

#include<sys/types.h>       //pthread_t , pthread_attr_t and so on.

#include<stdio.h>

#include<netinet/in.h>      //structure sockaddr_in

#include<arpa/inet.h>       //Func : htonl; htons; ntohl; ntohs

#include<assert.h>          //Func :assert

#include<string.h>          //Func :memset

#include<unistd.h>          //Func :close,write,read

#define SOCK_PORT 9988

#define BUFFER_LENGTH 1024

#define MAX_CONN_LIMIT 512     //MAX connection limit



static void Data_handle(void * sock_fd);   //Only can be seen in the file



int main()

{

    int sockfd_server;

    int sockfd;

    int fd_temp;

    struct sockaddr_in s_addr_in;

    struct sockaddr_in s_addr_client;

    int client_length;



    sockfd_server = socket(AF_INET,SOCK_STREAM,0);  //ipv4,TCP

    assert(sockfd_server != -1);



    //before bind(), set the attr of structure sockaddr.

    memset(&s_addr_in,0,sizeof(s_addr_in));

    s_addr_in.sin_family = AF_INET;

    s_addr_in.sin_addr.s_addr = htonl(INADDR_ANY);  //trans addr from uint32_t host byte order to network byte order.

    s_addr_in.sin_port = htons(SOCK_PORT);          //trans port from uint16_t host byte order to network byte order.

    fd_temp = bind(sockfd_server,(struct scokaddr *)(&s_addr_in),sizeof(s_addr_in));

    if(fd_temp == -1)

    {

        fprintf(stderr,"bind error!\n");

        exit(1);

    }



    fd_temp = listen(sockfd_server,MAX_CONN_LIMIT);

    if(fd_temp == -1)

    {

        fprintf(stderr,"listen error!\n");

        exit(1);

    }



    while(1)

    {

        printf("waiting for new connection...\n");

        pthread_t thread_id;

        client_length = sizeof(s_addr_client);



        //Block here. Until server accpets a new connection.

        sockfd = accept(sockfd_server,(struct sockaddr_*)(&s_addr_client),(socklen_t *)(&client_length));

        if(sockfd == -1)

        {

            fprintf(stderr,"Accept error!\n");

            continue;                               //ignore current socket ,continue while loop.

        }

        printf("A new connection occurs!\n");

        if(pthread_create(&thread_id,NULL,(void *)(&Data_handle),(void *)(&sockfd)) == -1)

        {

            fprintf(stderr,"pthread_create error!\n");

            break;                                  //break while loop

        }

    }



    //Clear

    int ret = shutdown(sockfd_server,SHUT_WR); //shut down the all or part of a full-duplex connection.

    assert(ret != -1);



    printf("Server shuts down\n");

    return 0;

}



static void Data_handle(void * sock_fd)

{

    int fd = *((int *)sock_fd);

    int i_recvBytes;

    char data_recv[BUFFER_LENGTH];

    const char * data_send = "Server has received your request!\n";



    while(1)

    {

        printf("waiting for request...\n");

        //Reset data.

        memset(data_recv,0,BUFFER_LENGTH);



        i_recvBytes = read(fd,data_recv,BUFFER_LENGTH);

        if(i_recvBytes == 0)

        {

            printf("Maybe the client has closed\n");

            break;

        }

        if(i_recvBytes == -1)

        {

            fprintf(stderr,"read error!\n");

            break;

        }

        if(strcmp(data_recv,"quit")==0)

        {

            printf("Quit command!\n");

            break;                           //Break the while loop.

        }

        printf("read from client : %s\n",data_recv);

        if(write(fd,data_send,strlen(data_send)) == -1)

        {

            break;

        }

    }



    //Clear

    printf("terminating current client_connection...\n");

    close(fd);            //close a file descriptor.

    pthread_exit(NULL);   //terminate calling thread!

}

client.c:

#include<stdlib.h>

#include<sys/socket.h>

#include<sys/types.h>       //pthread_t , pthread_attr_t and so on.

#include<stdio.h>

#include<netinet/in.h>      //structure sockaddr_in

#include<arpa/inet.h>       //Func : htonl; htons; ntohl; ntohs

#include<assert.h>          //Func :assert

#include<string.h>          //Func :memset

#include<unistd.h>          //Func :close,write,read

#define SOCK_PORT 9988

#define BUFFER_LENGTH 1024

int main()

{

    int sockfd;

    int tempfd;

    struct sockaddr_in s_addr_in;

    char data_send[BUFFER_LENGTH];

    char data_recv[BUFFER_LENGTH];

    memset(data_send,0,BUFFER_LENGTH);

    memset(data_recv,0,BUFFER_LENGTH);



    sockfd = socket(AF_INET,SOCK_STREAM,0);       //ipv4,TCP

    if(sockfd == -1)

    {

        fprintf(stderr,"socket error!\n");

        exit(1);

    }



    //before func connect, set the attr of structure sockaddr.

    memset(&s_addr_in,0,sizeof(s_addr_in));

    s_addr_in.sin_addr.s_addr = inet_addr("127.0.0.1");      //trans char * to in_addr_t

    s_addr_in.sin_family = AF_INET;

    s_addr_in.sin_port = htons(SOCK_PORT);



    tempfd = connect(sockfd,(struct sockaddr *)(&s_addr_in),sizeof(s_addr_in));

    if(tempfd == -1)

    {

        fprintf(stderr,"Connect error! \n");

        exit(1);

    }



    while(1)

    {

        printf("Please input something you wanna say(input \"quit\" to quit):\n");

        gets(data_send);

        //scanf("%[^\n]",data_send);         //or you can also use this

        tempfd = write(sockfd,data_send,BUFFER_LENGTH);

        if(tempfd == -1)

        {

            fprintf(stderr,"write error\n");

            exit(0);

        }



        if(strcmp(data_send,"quit") == 0)  //quit,write the quit request and shutdown client

        {

            break;

        }

        else

        {

            tempfd = read(sockfd,data_recv,BUFFER_LENGTH);

            assert(tempfd != -1);

            printf("%s\n",data_recv);

            memset(data_send,0,BUFFER_LENGTH);

            memset(data_recv,0,BUFFER_LENGTH);

        }

    }



    int ret = shutdown(sockfd,SHUT_WR);       //or you can use func close()--<unistd.h> to close the fd

    assert(ret != -1);

    return 0;

}