linux网络编程课设报告(共13页).doc

精选优质文档-倾情为你奉上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.h"int main(int argc, char *argv)int sock_listen, sock_control, port, pid;if (argc != 2) printf("usage: ./ftserve portn");exit(0);port = atoi(argv1);/ create socketif (sock_listen = socket_create(port) < 0 ) perror("Error creating socket");exit(1);while(1) / wait for client request/ create new socket for control connectionif (sock_control = socket_accept(sock_listen)< 0 )break;/ create child process to do actual file transferif (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 over 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 Requested 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 blockif (send(sock_data, data, num_read, 0) < 0)perror("error sending filen"); while (num_read > 0);/ send message: 226: closing conn, file transfer successfulsend_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 | tail -n+2 > tmp.txt");if ( rs < 0) exit(1);fd = fopen("tmp.txt", "r");if (!fd) exit(1);/* Seek to the beginning of the file */fseek(fd, SEEK_SET, 0);send_response(sock_control, 1); /startingmemset(data, 0, MAXSIZE);while (num_read = fread(data, 1, MAXSIZE, fd) > 0) if (send(sock_data, data, num_read, 0) < 0) perror("err");memset(data, 0, MAXSIZE);fclose(fd);send_response(sock_control, 226);/ send 226return 0;/* * Open data connection to client * Returns: socket for data connection * or -1 on error */int ftserve_start_data_conn(int sock_control)char buf1024;int wait, sock_data;/ Wait for go-ahead on control connif (recv(sock_control, &wait, sizeof wait, 0) < 0 ) perror("Error while waiting");return -1;/ Get client addressstruct sockaddr_in client_addr;socklen_t len = sizeof client_addr;getpeername(sock_control, (struct sockaddr*)&client_addr, &len);inet_ntop(AF_INET, &client_addr.sin_addr, buf, sizeof(buf);/ Initiate data connection with clientif (sock_data = socket_connect(CLIENT_PORT_ID, buf) < 0)return -1;return sock_data;/* * Authenticate a user's credentials * Return 1 if authenticated, 0 if not */int ftserve_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) != -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 whitespacetrimstr(password, (int)strlen(password);if (strcmp(user,username)=0) && (strcmp(pass,password)=0) auth = 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 usernameif ( (recv_data(sock_control, buf, sizeof(buf) ) = -1) perror("recv errorn"); exit(1);int i = 5;int n = 0;while (bufi != 0)usern+ = bufi+;/ tell client we're ready for passwordsend_response(sock_control, 331);/ Wait to recieve passwordmemset(buf, 0, MAXSIZE);if ( (recv_data(sock_control, buf, sizeof(buf) ) = -1) perror("recv 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, MAXSIZE);memset(cmd, 0, 5);memset(arg, 0, MAXSIZE);/ Wait to recieve commandif (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) | (strcmp(cmd, "PASS")=0) |(strcmp(cmd, "LIST")=0) | (strcmp(cmd, "RETR")=0) rc = 200; else /invalid commandrc = 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 welcome messagesend_response(sock_control, 220);/ Authenticate userif (ftserve_login(sock_control) = 1) send_response(sock_control, 230); else send_response(sock_control, 430);exit(0);while (1) / Wait for commandint rc = ftserve_recv_cmd(sock_control, cmd, arg);if (rc < 0) | (rc = 221) break;if (rc = 200 ) / Open data connection with clientif (sock_data = ftserve_start_data_conn(sock_control) < 0) close(sock_control);exit(1); / Execute commandif (strcmp(cmd, "LIST")=0) / Do listftserve_list(sock_data, sock_control); else if (strcmp(cmd, "RETR")=0) / Do get <filename>ftserve_retr(sock_control, sock_data, arg);/ Close data connectionclose(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。专心-专注-专业