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퀴즈 응용 프로그램을 만들어야합니다. 응용 프로그램에 대한기능 동작 선택 - 다중 클라이언트 퀴즈
세부 사항 :
1. 각 클라이언트가 퀴즈에 참여하기 전에 서버에 등록 할 수 있습니다. 서버는 각 사용자의 사용자 이름을 물어보고 각 사용자에 대한 임시 ID를 생성합니다.
2. 등록 프로세스 후 클라이언트에 성공적으로 연결된 서버는 질문입니다.
3. 클라이언트가 응답으로 응답합니다.
4. 서버는 타임 스탬프가있는 다른 클라이언트의 응답을 수신하며, Δt라고하는 각 클라이언트의 시간 차이는 입니다.
Define such as:
∆t = (Time Question sent - Time answer received) - RTT
Where RTT is Round Trip Time
- 서버는, 그 ΔT는 모두 최소하고 점수를 얻을하지 않습니다 유물을 얻을 것입니다 어떤 점수를 클라이언트로 응답 클라이언트를 선택합니다.
- 보낸 후 질문 서버는 (T)라는 특정 기간 동안 응답을 기다립니다. 클라이언트가 'T'시간 내에 응답하지 않으면 Server는 해당 질문을 건너 뛰고 다음 질문으로갑니다. 내 서버 코드
A. A main while loop which runs once for each question. B. Inside this first I am accepting login for 10 seconds. Here I am assigning user Id and all other initialization stuff. C. Then using `select` to check which are available for writing. To available connections I am checking `RTT` and then sending question to each user. D. Then I am waiting for some time to get answers. Here I am using `select` to determine where the answer is available to read. E. Then I am repeating steps C. and D.문제의 메인 루프의
의사 코드는 : 나는 하나의 클라이언트 만 연결하면
내 코드는 질문의 수에 대해 잘 작동합니다.
하지만 같은 클라이언트 코드를 여러 클라이언트에서이 코드를 테스트 할 때 : 모두를위한
- 로그인 OK입니다.
- 모든 사람에게 첫 번째 질문 보내기가 잘 작동합니다.
- 그런 다음 응답을 기다리는 동안 한 클라이언트에서만 답변을 받았습니다. 각 클라이언트는 응답이 전송되었음을 보여줍니다. 두 번째 클라이언트의 경우 두 번째
select함수는 읽을 수있는 데이터 가용성을 반환하지 않습니다.
내 클라이언트 코드가 작동하지 않는 이유는 무엇입니까? (내 말에 따르면, 오류는 답을 얻는 데 어딘가에있다.)
내 코드 :
패킷의 구조는 변수 이름에서 쉽게 이해 될 수 보내 .
Server.c :
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <error.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>
#include <time.h>
#define PORT "3490" //the port user will be connecting to
#define BACKLOG 10 //how many pending connection queue will hold
#define maxUser 10
#define LOGIN_OK "OK"
#define LOGIN_WrongPassword "NP"
#define LOGIN_WrongUsername "NU"
#define MAX_USERS 10
#define MAX_ANSWER_TIME 10
#define LOGIN_WAIT 10
#define TOTAL_QUES "3"
int users[MAX_USERS][3] = {}; //index is userID, 0 is no user
void sigchld_handler(int s)
{
while(waitpid(-1, NULL, WNOHANG) > 0);
}
//get sockaddr, IPv4 or IPv6
int timer;
void alarm_handler(int s) {
timer = 0;
}
wrongRecv(ssize_t recvd, ssize_t expctd)
{
if(recvd != expctd)
{
printf("Recvd(%zd) bytes not equal to expected(%zd) bytes\n",recvd,expctd);
//getchar();
}
}
//void nextQues(char* quesMsg, char* ques, char* optA, char* optB, char* optC, char* optD)
int nextQues(char* quesMsg, int QID)
{
char ques[40], optA[10], optB[10], optC[10], optD[10], quesId[5];
sprintf(quesId,"%d",QID);
strncpy(ques, "This is the question?",22);
strncpy(optA, "OptionA", 7); strncpy(optB, "OptionB", 7); strncpy(optC, "OptionC", 7); strncpy(optD, "OptionD", 7);
strncpy(quesMsg,quesId,5);
strncpy(quesMsg + 05,ques,40);
strncpy(quesMsg + 45,optA,10);
strncpy(quesMsg + 55,optB,10);
strncpy(quesMsg + 65,optC,10);
strncpy(quesMsg + 75,optD,10);
return 0;
}
//void answerCheck(char* ques, char* optA, char* optB, char* optC, char* optD, char* usrResponse, int rtt, int timeTaken)
void answerCheck(int fd, char usrResponse[6], int rtt, int timeTaken)
{
int responseTime, i;
char actualAnswer[1];
char quesId[5];
printf("fd(%d) quesid(%s) response(%c) rtt(%d) timeTaken(%d)\n", fd, usrResponse, usrResponse[5], rtt, timeTaken);
strncpy(quesId, usrResponse, 5);
actualAnswer[0] = 'B';//we have quesId we can find actual answer on basis of it
if(actualAnswer[0] == usrResponse[5])
{
//printf("%s\n","+++++");
responseTime = timeTaken - rtt;
//printf("Response Time(%d)\n",responseTime);
//save it with user id
//finding userid
for(i = 0; i < MAX_USERS; i++) {
if(users[i][1] == fd) {
users[i][2] = responseTime;//saving it
//printf("%d\n",i);
}
}
}
}
int compareAnswer() {
int i, min = 2 * MAX_ANSWER_TIME, userIndex;
for(i = 0; i < MAX_USERS; i++) {
if(users[i][2] < min) {
min = users[i][2];
userIndex = i;
}
}
//Increasing Score
users[userIndex][0]++;
//returning fd
return users[userIndex][1];
}
void users_deleteFd(int fd) {
int i;
for (i = 0; i < MAX_USERS; ++i)
{
if(users[i][1] == fd) {
users[i][1] =0;
return;
}
}
}
int rtt_check(int new_fd)
{
ssize_t send_ret, recv_ret;
char rtt_check[1];
time_t rtt1, rtt2;
rtt1 = time(NULL);
send_ret = send(new_fd, "r", 1, 0);
if(send_ret == 0)
{
return -2;
}
wrongRecv(send_ret, 1);
//printf("%s\n","Between two phase of rttCheck");
recv_ret = recv(new_fd, rtt_check, 1,0);
rtt2 = time(NULL);
if(recv_ret == 0)
{
return -2;
}
wrongRecv(recv_ret,1);
//printf("diff(%d)\n",(int) difftime(rtt2,rtt1));
return (int) difftime(rtt2,rtt1);
}
int login(char user[], char pass[])
{
//for user
static int Id = 0; //when have function getUserID, make it not static and also remove Id++;
if(!strcmp(user,"abhishek") && !strcmp(pass,"abhishek")) {
//Id = getUserID(user);
return ++Id;
}else if(!strcmp(user,"abhishek")){
return 0; //wrong password
}
return -1; //wrong username
}
int totalQues;
int login_setup(int new_fd)
{
//login inititalizations
char login_det[16];
char username[9],password[9], login_statMsg[7], totalQuesMsg[5] = TOTAL_QUES;
totalQues = atoi(totalQuesMsg);
//for user
int userId;
//for wrongRecv
ssize_t send_ret,recv_ret;
//getting username and password
recv_ret = recv(new_fd,login_det,16,0);
if(recv_ret == 0)
{
return -2;
}
wrongRecv(recv_ret,16);
//extracting username nad password
strncpy(username,login_det,8);
strncpy(password,login_det+8,8);
username[8]='\0'; password[8]='\0';
//printf("username(%s) and password(%s)\n",username,password);
if((userId = login(username,password)) > 0) {
//printf("%d\n",userId);
//sending status
strncpy(login_statMsg, LOGIN_OK, 2);
strncpy(login_statMsg + 2, totalQuesMsg , 5);
send_ret = send(new_fd, login_statMsg,7,0);
if(send_ret == 0)
{
return -2;
}
wrongRecv(send_ret,7);
//TODO error checking then handling if error
//users[userId][0] = 0; //score
users[userId][1] = new_fd; //file descriptor associated with this user
//users[userId][2] = 0; //answer time
return 1;
}
else if(userId == -1) { //wrong username
strncpy(login_statMsg, LOGIN_WrongUsername, 2);
strncpy(login_statMsg + 2, totalQuesMsg , 5);
send_ret = send(new_fd, login_statMsg,7,0);
if(send_ret == 0)
{
return -2;
}
wrongRecv(send_ret,7);
return 0;
}
else{
strncpy(login_statMsg, LOGIN_WrongPassword, 2);
strncpy(login_statMsg + 2, totalQuesMsg , 5);
send_ret = send(new_fd, login_statMsg,7,0);
if(send_ret == 0)
{
return -2;
}
wrongRecv(send_ret,7);
return 0;
}
//TODO erorr handling of above two case
//TODO make login a loop
}
void *get_in_addr(struct sockaddr *sa)
{
if (sa->sa_family == AF_INET) {
return &(((struct sockaddr_in*)sa)->sin_addr);
}
return &(((struct sockaddr_in6*)sa)->sin6_addr);
}
int main(void)
{
int listen_fd, new_fd; // listen on sock_fd, new connection on new_fd
struct addrinfo hints, *servinfo, *p;
struct sockaddr_storage their_addr;//connection's address info
socklen_t sin_size;
int yes=1;
char s[INET6_ADDRSTRLEN];
int rv;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;//IPv4 or IPv6
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE; // use my IP
if((rv = getaddrinfo(NULL,PORT, &hints, &servinfo)) != 0){ //getting which IPv server supports
fprintf(stderr, "getaddrinfo: %s\n",gai_strerror(rv));
return 1;
}
//loop through all the result and bind to the first we can
for(p = servinfo; p != NULL; p = p->ai_next){
if((listen_fd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1){
perror("server : socket");
continue;
}
if(setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1){
perror("set sockopt");
exit(1);
}
if(bind(listen_fd, p->ai_addr, p->ai_addrlen) == -1){
close(listen_fd);
perror("server: bind");
continue;
}
break;
}
if(p == NULL) {
fprintf(stderr, "server:failed to bind\n");
return 2;
}
freeaddrinfo(servinfo);//all done with this structure
if(listen(listen_fd, BACKLOG) == -1){
perror("listen");
exit(1);
}
//printf("listen_fd(%d)\n",listen_fd);
// sa.sa_handler = sigchld_handler; // reap all dead processes
// sigemptyset(&sa.sa_mask);
// sa.sa_flags = SA_RESTART;
// if(sigaction(SIGCHLD, &sa, NULL) == -1){
// perror("sigaction");
// exit(1);
// }
printf("server waiting for connections.....\n");
fd_set master; //master file descriptor list
fd_set read_fds; //temp file descriptor list for select()
int fdmax;
FD_ZERO(&master); //clear the master and temp sets
FD_ZERO(&read_fds);
FD_SET(listen_fd, &master);
//keep track of the bigge file descriptor
fdmax = listen_fd; // so far it is this one
ssize_t recv_ret, send_ret;
//for login
int loginStatus;
struct sigaction sa;
sa.sa_handler = alarm_handler;
sigemptyset(&sa.sa_mask);
//sa.sa_flags = SA_RESTART;
if(sigaction(SIGALRM, &sa, NULL) == -1){
perror("sigaction");
exit(1);
}
//login while
alarm(LOGIN_WAIT);//accepting login only for 10 seconds
timer = 1;
printf("\n-----------------------------Waiting for users to login for %d seconds.-----------------------------\n",LOGIN_WAIT);
while(timer) {
sin_size = sizeof their_addr;
new_fd = accept(listen_fd, (struct sockaddr *)&their_addr, &sin_size);
if(new_fd == -1){
//perror("accept");
break;// this break is very important , as we are using alarm(Signals) and accept is a blocking function
//If accept is in blocked sate and our signal comes then accept will exit returning error. So
//if error then we have to break else next satements will run on falsy values.
//In reality we dont need this as I alredy set the SA_RESTART flag in sigaction which means
//after returning from the signal handler restart the activity on which you are previously
//instead of starting execution from next line.
}else {
inet_ntop(their_addr.ss_family, get_in_addr((struct sockaddr *)&their_addr), s, sizeof s);
printf("server : got connection from %s\n", s);
//LOGIN //need to call login function via thread because this
//may stop the function if user doesnot respond
loginStatus = login_setup(new_fd);
//adding to select checkup
if(loginStatus) {
printf("User Loginned Succesfully\n");
}
}
}
printf("-----------------------------Login Closed. Now starting the QUIZ.-----------------------------\n");
//for randome seek
srand(time(NULL));
//for main loop counter
int i, win_fd;
//for questions
int QID = 0;
int maxQues_Len = 40, maxOpt_len = 10, maxQuesId_len = 5;//including '\0' this time
char quesMsg[80], answer[6];//score doesnot include \0
//char ques[40], optA[10], optB[10], optC[10], optD[10];
//for time calculation of each answer
ssize_t time_ques, time_ans;
//getting all avialable participants
fdmax = 0;
FD_ZERO(&master);
for(i = 0; i < MAX_USERS; i++) {
if((new_fd = users[i][1]) != 0){
FD_SET(new_fd, &master);
if(new_fd > fdmax)
fdmax = new_fd;
//printf("%d\n",new_fd);
}
}
int current_rtt;
//while for main quiz
while(totalQues--) {
//checking who are ready for witing
if(select(fdmax+1, NULL, &master, NULL, NULL) == -1){//here select will return withh all the descriptors which are
//ready to write , all others have to miss this question
perror("select");
exit(1);
}
//setting which question to send
QID++;
//for sending questions to all
for(i = 0; i <= fdmax; i++) {
if(FD_ISSET(i, &master)) {
//rtt check
current_rtt = rtt_check(i);
if(current_rtt == -2) {//connection closed
FD_CLR(i, &master);
users_deleteFd(i);
continue;
}
//setting question
//nextQues(quesMsg, ques, optA, optB, optC, optD);
nextQues(quesMsg, QID);
printf("Sending Question QID(%s) fd(%d)\n",quesMsg,i);
//send a question
time_ques = time(NULL);
send_ret = send(i, quesMsg, maxQues_Len + 4 * maxOpt_len + maxQuesId_len, 0);
if(send_ret == 0) {//connection closed
FD_CLR(i, &master);
users_deleteFd(i);
continue;
}
wrongRecv(send_ret, maxQues_Len + 4 * maxOpt_len + maxQuesId_len);
}
}
//ASSUMING Question is send ot all the users at same time
//receiving and waiting for answers
alarm(MAX_ANSWER_TIME);
timer = 1;
FD_ZERO(&read_fds);
read_fds = master;
// unsigned int qq = read_fds.fd_count;
// for (int ii = 0; ii < qq; ++ii)
// {
// printf("%d\n",read_fds.fd_array[i]);
// }
while(timer) {
//printf("HURRAY\n");
if(select(fdmax+1, &read_fds, NULL, NULL, NULL) <=0){
perror("select");
//exit(4);
break;//break is important. Explained above
}
for(i = 0; i <= fdmax; i++) {
//printf("Recving answer I(%d)\n",i);
if(FD_ISSET(i, &read_fds)) {
//receiving answer
//TODO if we get answer to wrong ques
printf("Recving answer I(%d) fdmax (%d)\n",i,fdmax);
recv_ret = recv(i,answer,6,0);
time_ans = time(NULL);
wrongRecv(recv_ret,6);
printf("%s\n",answer);
if(recv_ret == 0)//connection closed
{
FD_CLR(i, &read_fds);
FD_CLR(i, &master);
users_deleteFd(i);
continue;
}else if(recv_ret > 0){
if(QID == atoi(answer)) { //we have received the answer to this question so remove the user from wait answer loop
FD_CLR(i, &read_fds);
//printf("%s i(%d)\n","#######",i);
answerCheck(i ,answer, current_rtt, (int) difftime(time_ans,time_ques));
//printf("Answer(%c)\n",answer[0]);
}
else{//we have recvd something unexpectable so ignore for NOW
}
}
//time_t cccc = time(NULL);
//printf("%s I(%d)\n",ctime(&cccc),i);
}
}
}
//comparing answers
win_fd = compareAnswer();
//sending score
}
return 0;
}
클라이언트.C :
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#define PORT "3490" //the port client will be connecting to
#define MAXDATASIZE 100 // max number of bytes we can get at once
//get sockaddr ,IPv4 or IPv6:
void *get_in_addr(struct sockaddr *sa)
{
if(sa->sa_family ==AF_INET) {
return &(((struct sockaddr_in*)sa)->sin_addr);
}
return &(((struct sockaddr_in6*)sa)->sin6_addr);
}
wrongRecv(ssize_t recvd, ssize_t expctd)
{
if(recvd != expctd)
{
printf("Recvd(%zd) bytes not equal to expected(%zd) bytes\n",recvd,expctd);
getchar();
}
}
void rtt_check(int sockfd)
{
ssize_t send_ret, recv_ret;
char rtt_check[1];
recv_ret = recv(sockfd, rtt_check, 1,0);
wrongRecv(recv_ret,1);
sleep(1);//to check
send_ret = send(sockfd, "r", 1, 0);
wrongRecv(send_ret, 1);
return;
}
int main(int argc, char *argv[])
{
int sockfd, numbytes;
char buf[MAXDATASIZE];
struct addrinfo hints, *servinfo, *p;
int rv;
char s[INET6_ADDRSTRLEN];
if(argc != 2) {
fprintf(stderr,"usage: client hostname\n");
exit(1);
}
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
if((rv = getaddrinfo(argv[1], PORT, &hints, &servinfo)) != 0) {
fprintf(stderr,"getaddrinfo: %s\n",gai_strerror(rv));
return 1;
}
//lopp through all the results and connect to the first we can
for(p = servinfo; p != NULL; p = p->ai_next) {
if((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1){
perror("client: socket");
continue;
}
if(connect(sockfd, p->ai_addr, p->ai_addrlen) == -1){
close(sockfd);
perror("client: connect");
continue;
}
break;
}
if(p ==NULL) {
fprintf(stderr,"client: failed to connect\n");
return 2;
}
inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr), s, sizeof s);
printf("client : connecting to %s\n", s);
freeaddrinfo(servinfo); // all done with this structure
char login_det[17] = "abhishekabhishek";
char login_retMsg[7], login_stat[3], totalQuesMsg[5];
int totalQues;
//sending login details
ssize_t send_ret,recv_ret;
send_ret = send(sockfd, login_det,16,0);
wrongRecv(send_ret,16);
//receiving login status
recv_ret = recv(sockfd,login_retMsg,7,0);
wrongRecv(recv_ret,7);
strncpy(login_stat, login_retMsg, 2);
login_stat[2] = '\0';
printf("Login Status(%s)\n",login_stat);
strncpy(totalQuesMsg, login_retMsg + 2, 5);
totalQues = atoi(totalQuesMsg);
printf("totalQues(%d)\n",totalQues);
if(!strcmp(login_stat,"OK")) { //login ok
char quesId[5];
int maxQues_Len = 40, maxOpt_len = 10, maxQuesId_len = 5;//including '\0' this time
char quesMsg[80], scoreMsg[1];//score doesnot include \0
char ques[40], optA[10], optB[10], optC[10], optD[10];
char answer[6];
while(totalQues--) {
//checking rtt
rtt_check(sockfd);
//receving question
recv_ret = recv(sockfd, quesMsg, maxQues_Len + 4 * maxOpt_len + maxQuesId_len ,0);
wrongRecv(recv_ret, maxQues_Len + 4 * maxOpt_len + maxQuesId_len);
strncpy(quesId,quesMsg,5);
strncpy(ques, quesMsg + 05, 40);
strncpy(optA, quesMsg + 45, 10);
strncpy(optB, quesMsg + 55, 10);
strncpy(optC, quesMsg + 65, 10);
strncpy(optD, quesMsg + 75, 10);
printf("QUESID(%s) Question(%s), A(%s) , B(%s) , C(%s) , D(%s)\n", quesId, ques, optA, optB, optC, optD);
//choose answer
scoreMsg[0] = 'B';
strncpy(answer,quesId, 5);
answer[5] = scoreMsg[0];
sleep(5);
//sending answer
send_ret = send(sockfd, answer,6,0);
wrongRecv(send_ret,6);
printf("%s\n","Answer Message Sent");
// if((numbytes = recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
// perror("recv");
// exit(1);
// }
// buf[numbytes] = '\0';
// printf("client: received '%s'\n",buf);
}
}
//TODO wrong login
close(sockfd);
return 0;
}
아니요, 선택을 다시 호출하고 agian입니다. (각각의 for 루프 선택이 시간까지 다시 호출 된 후). 또한 첫 번째 답변을받은 후 코드를 실행하면 시간까지 선택에서 프로그램이 차단되므로 이는 선택을 다시 호출하고 있음을 의미합니다. –
@knoxxs, 선택을 다시 부릅니다. 문제는 두 번째로 호출 될 때 read_fds의 값입니다. 나는 이것이 숙제 과제이기 때문에 필요한 정확한 변화를 포기하지 않는 것을 선호한다. –
나는 그것을 얻지 못한다. read_fds를 탐색 할 수있는 방법이 있습니까? 검색했지만 찾지 못했습니다. H.W. 할당 문제. 과제 제출 시간이 끝났습니다. 나 자신을 요구하고 있습니다. 하지만 당신이 지적했듯이 나는 첫 번째 대답을받은 후에'read_fds '에 대한 파일 디스크립터만을 삭제할 것이라고 생각한다. 그리고'master '로부터 복사 한 것처럼, 여전히 다른 연결의 파일 기술자를 포함합니다. –