linux网络编程课程教学设计.docx

1、linux网络编程课程教学设计Linux网络编程课程设计 班级：姓名：指导老师： 一、设计背景Linux操作系统作为一个开源的操作系统被越来越多的人所应用，它的好处在于操作系统源代码的公开化！只要是基于GNU公约的软件你都可以任意使用并修改它的源代码。通过这次课程设计能更好的学习网络编程知识和掌握LINUX平台上应用程序设计开发的过程，将大学四年所学知识综合运用，为未来的工作学习打下基础。二、设计目的 1、学习epoll 跟FTP被动模式 2、掌握linux基本命令 ，例如ls、cd、login； 3、学会如何编译、运行三、环境要求 1、centos 64位操作系统2、gcc编译器四、设计原理

2、 41客户端 客户端程序的主要任务有以下3个： （1）、分析用户输入的命令。 （2）、根据命令向服务器发出请求 （3）、接受服务器返回请求的结果 客户端为用户提供了3种命令： （1）、get:从服务器下载文件 （2）、list:列出客户端当前目录的内容（3）、quit离开 4.2 服务器端（1）、分析请求代码。 （2）、根据请求代码做相应的处理 （3）、等待返回结果或者应答信息五、软件测试结果六、部分主代码 #include ftserve.hint main(int argc, char *argv) int sock_listen, sock_control, port, pid; if

3、(argc != 2) printf(usage: ./ftserve portn); exit(0); port = atoi(argv1); / create socket if (sock_listen = socket_create(port) 0 ) perror(Error creating socket); exit(1); while(1) / wait for client request / create new socket for control connection if (sock_control = socket_accept(sock_listen) 0 ) b

4、reak; / create child process to do actual file transfer if (pid = fork() 0) perror(Error forking child process); else if (pid = 0) close(sock_listen); ftserve_process(sock_control); close(sock_control); exit(0); close(sock_control); close(sock_listen); return 0;/* * Send file specified in filename o

5、ver data connection, sending * control message over control connection * Handles case of null or invalid filename */void ftserve_retr(int sock_control, int sock_data, char* filename) FILE* fd = NULL; char dataMAXSIZE; size_t num_read; fd = fopen(filename, r); if (!fd) / send error code (550 Requeste

6、d action not taken) send_response(sock_control, 550); else / send okay (150 File status okay) send_response(sock_control, 150); do num_read = fread(data, 1, MAXSIZE, fd); if (num_read 0) printf(error in fread()n); / send block if (send(sock_data, data, num_read, 0) 0); / send message: 226: closing c

7、onn, file transfer successful send_response(sock_control, 226); fclose(fd); /* * Send list of files in current directory * over data connection * Return -1 on error, 0 on success */int ftserve_list(int sock_data, int sock_control) char dataMAXSIZE; size_t num_read; FILE* fd; int rs = system(ls -l |

8、tail -n+2 tmp.txt); if ( rs 0) if (send(sock_data, data, num_read, 0) 0) perror(err); memset(data, 0, MAXSIZE); fclose(fd); send_response(sock_control, 226); / send 226 return 0; /* * Open data connection to client * Returns: socket for data connection * or -1 on error */int ftserve_start_data_conn(

9、int sock_control) char buf1024; int wait, sock_data; / Wait for go-ahead on control conn if (recv(sock_control, &wait, sizeof wait, 0) 0 ) perror(Error while waiting); return -1; / Get client address struct sockaddr_in client_addr; socklen_t len = sizeof client_addr; getpeername(sock_control, (struc

10、t sockaddr*)&client_addr, &len); inet_ntop(AF_INET, &client_addr.sin_addr, buf, sizeof(buf); / Initiate data connection with client if (sock_data = socket_connect(CLIENT_PORT_ID, buf) 0) return -1; return sock_data; /* * Authenticate a users credentials * Return 1 if authenticated, 0 if not */int ft

11、serve_check_user(char*user, char*pass) char usernameMAXSIZE; char passwordMAXSIZE; char *pch; char bufMAXSIZE; char *line = NULL; size_t num_read; size_t len = 0; FILE* fd; int auth = 0; fd = fopen(.auth, r); if (fd = NULL) perror(file not found); exit(1); while (num_read = getline(&line, &len, fd)

12、!= -1) memset(buf, 0, MAXSIZE); strcpy(buf, line); pch = strtok (buf, ); strcpy(username, pch); if (pch != NULL) pch = strtok (NULL, ); strcpy(password, pch); / remove end of line and whitespace trimstr(password, (int)strlen(password); if (strcmp(user,username)=0) & (strcmp(pass,password)=0) auth =

13、1; break; free(line); fclose(fd); return auth;/* * Log in connected client */int ftserve_login(int sock_control) char bufMAXSIZE; char userMAXSIZE; char passMAXSIZE; memset(user, 0, MAXSIZE); memset(pass, 0, MAXSIZE); memset(buf, 0, MAXSIZE); / Wait to recieve username if ( (recv_data(sock_control,

14、buf, sizeof(buf) ) = -1) perror(recv errorn); exit(1); int i = 5; int n = 0; while (bufi != 0) usern+ = bufi+; / tell client were ready for password send_response(sock_control, 331); / Wait to recieve password memset(buf, 0, MAXSIZE); if ( (recv_data(sock_control, buf, sizeof(buf) ) = -1) perror(rec

15、v errorn); exit(1); i = 5; n = 0; while (bufi != 0) passn+ = bufi+; return (ftserve_check_user(user, pass);/* * Wait for command from client and * send response * Returns response code */int ftserve_recv_cmd(int sock_control, char*cmd, char*arg) int rc = 200; char bufferMAXSIZE; memset(buffer, 0, MA

16、XSIZE); memset(cmd, 0, 5); memset(arg, 0, MAXSIZE); / Wait to recieve command if (recv_data(sock_control, buffer, sizeof(buffer) ) = -1) perror(recv errorn); return -1; strncpy(cmd, buffer, 4); char *tmp = buffer + 5; strcpy(arg, tmp); if (strcmp(cmd, QUIT)=0) rc = 221; else if(strcmp(cmd, USER)=0)

17、| (strcmp(cmd, PASS)=0) | (strcmp(cmd, LIST)=0) | (strcmp(cmd, RETR)=0) rc = 200; else /invalid command rc = 502; send_response(sock_control, rc); return rc;/* * Child process handles connection to client */void ftserve_process(int sock_control) int sock_data; char cmd5; char argMAXSIZE; / Send welc

18、ome message send_response(sock_control, 220); / Authenticate user if (ftserve_login(sock_control) = 1) send_response(sock_control, 230); else send_response(sock_control, 430); exit(0); while (1) / Wait for command int rc = ftserve_recv_cmd(sock_control, cmd, arg); if (rc 0) | (rc = 221) break; if (r

19、c = 200 ) / Open data connection with client if (sock_data = ftserve_start_data_conn(sock_control) 0) close(sock_control); exit(1); / Execute command if (strcmp(cmd, LIST)=0) / Do list ftserve_list(sock_data, sock_control); else if (strcmp(cmd, RETR)=0) / Do get ftserve_retr(sock_control, sock_data, arg); / Close data connection close(sock_data); 七、设计总结通过本次的linux程序与设计课程设计让我们学会使用linux系统和socket，极大的丰富了linux系统下编程和网络方面的知识，锻炼了动手能力，为以后的工作学习打下了坚实的基础。