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UDP server/ client exchange bulletin Hi everyone! I'm a freshman in our forum. To the beginning, hope all of you have a nice day.
I'm having an assignment about UDP server client which exchange their bulletin to each other. Similar my code below i successfully ran completely with TCP. However, i can't figure out what is the reason why my code does not work. I'm totally clueless now.
Here is my code :
server:
client:Code:#include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <string.h> #include <stdlib.h> #include <stdio.h> int main(int argc,char* argv[]) { //---------------- tao cac struct ban tin---------- struct hello { char hello_id[11];//10 ky tu dientu-k53 + 1 ki tu ket thuc long int hello_len; //32bit long int hello_detect; char mail_user[50]; //mail user from client } HEL; HEL.hello_detect=0; struct acknowledgement { char ack_id[11]; long int ack_len; long int ack_detect; char client_mail[50]; //tra ve mail user cho client char ack_state[20]; //trang thai "success" or "failed" } ACK; strcpy(ACK.ack_id,"dientu-K53"); ACK.ack_detect=1; //char ack_state[]; //vua thay doi struct bye { char bye_id[11]; long int bye_detect; } BYE; strcpy(BYE.bye_id,"dientu-K53"); BYE.bye_detect=2; int dem=0; //----------ket thuc tao ban tin ----------------- int serverSocket; serverSocket=socket(PF_INET,SOCK_DGRAM,0); if(serverSocket==-1) { perror("UDP server socket !!! \n"); close(serverSocket); exit(1); } int i=1; //option for enabling reuse option below int check; /*check=setsockopt(serverSocket,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(int)); if(check=-1) { perror("failed to set reuse\n"); } */ //---------loading socket address structure------------ struct sockaddr_in serverAddress; //struct sockaddr_in clientAddress; serverAddress.sin_family=AF_INET; serverAddress.sin_port=htons(5011); serverAddress.sin_addr.s_addr=INADDR_ANY; //socklen_t len=sizeof (struct sockaddr_in); //-------------------define length of clientaddr , serveraddr-------------------- //int clientaddrlen=sizeof(clientAddress); int serveraddrlen=sizeof(serverAddress); check=bind(serverSocket,(struct sockaddr *)&serverAddress,serveraddrlen); if(bind==-1) { perror("failed to bind socket address structure\n"); close(serverSocket); exit(0); } //gia tri tra ve cua bind trong UDP connectionless la con tro else {//--------------DATA handling begin ---------------------- printf("chuan bi xu ly \n"); //------------------------Declare prototypes------------------------- //struct sockaddr_in clientAddress; //len=sizeof(struct sockaddr_in); fd_set readfds; //check sockets ready for reading fd_set masterfds; //luu thay doi cua readfds FD_ZERO(&readfds); FD_ZERO(&masterfds); FD_SET(serverSocket,&masterfds); //add udp serverSocket vao array masterfds int max_fd=serverSocket; //=3 struct timeval timeout; //timeout cho select() timeout.tv_sec=90; timeout.tv_usec=0; int n_select; int close_fd=0; //khai bao kiem tra fd state do { //-----endless loop--------------- memcpy(&readfds,&masterfds,sizeof(masterfds)); //load masterfds to readfds printf("chuan bi select \n"); n_select=select(max_fd+1,&readfds,NULL,NULL,NULL); printf("da thuc hien ham select \n"); if (n_select < 0) { perror("SELECT"); exit(0); } else if (n_select == 0) { printf("Time out\n"); } else { i=serverSocket; // for (i = 0; i <= max_fd;i++) //duyet cac file descriptors //{ if (FD_ISSET(i,&readfds))//neu co file descriptor"ready to read" { //int close_fd = 0; //kiem tra socket co nen duoc dong sau khi xu ly hay ko? struct sockaddr_in clientAddress; int clientaddrlen=sizeof(clientAddress); //gan i =serverSocket //-----------------------Data processing--------------------------------------- printf("receive HELLO+send ACK bulletin\n"); printf("Receive data in socket %d\n",i); int nrecv ; //nhan mail tu remote client char mail_temp[100][50]; //danh sach tam dem++; //thao tac tren mail list dau tien nrecv=recvfrom(i,mail_temp[dem],50,0,(struct sockaddr*)&clientAddress,&clientaddrlen); //hello_mail if(nrecv==-1) { printf("In socket-received mail %d\n",i); perror("RECEIVE"); close_fd=1; }// end if nrecv_mail //hien thi chuoi printf("mail user tu client gui la: %s\n",mail_temp[dem]); //------------------------------------------------------- nrecv= recvfrom(i,HEL.hello_id,11,0,(struct sockaddr*)&clientAddress,&clientaddrlen); //PROBLEM HERE-chua gan default cho hello_id o client if (nrecv == -1) { printf("In socket-receive ID %d\n",i); perror("RECEIVE"); close_fd = 1; //co loi nao close_fd=1 de dong socket } // else // { printf("Hello_id received=%s.\n",HEL.hello_id); if(strcmp(HEL.hello_id,"dientu-K53")==0) //hello_id :dung-> tra ve 0 { printf("ban tin hop le \n"); goto moveon; } else { printf("ban tin khong hop le\n"); exit(0); } //nhan gia tri hello_len moveon: nrecv=recvfrom(i,&HEL.hello_len,4,0,(struct sockaddr*)&clientAddress,&clientaddrlen); if(nrecv==-1) { printf("In socket-received length: %d \n",i); perror("RECEIVE"); //close_fd=1; }//end if nrecv_len //nhan gia tri hello_detect nrecv=recvfrom(i,&HEL.hello_detect,4,0,(struct sockaddr*)&clientAddress,&clientaddrlen); if(nrecv==-1) { printf("In socket-received detect: %d \n",i); perror("RECEIVE"); close_fd=1; //dong socket } //Save email user vao mang 2 chieu char list_mail [100][50]; //mang 1 chieu 100 phan tu, moi phan tu 50 ki tu-> giong danh sach // int count=0; In_mail: strcpy(list_mail[dem],mail_temp[dem]); //cong luon printf("mail vua update vao list la: %s \n",list_mail[dem]); int j=1; printf("------------------Hien thi danh sach email:---------------\n"); for(j=1;j<=dem;j++) { printf(" mail thu %d : %s \n ",j,list_mail[j]); } printf("-------------------End my list----------------------"); //gan gia tri cho truong trang thai ACK.ack_state if(strcmp(list_mail[dem],mail_temp[dem])==0) //dung->return 0 { printf("luu email thanh cong \n"); strcpy(ACK.ack_state,"success"); printf("ack vua gan la %s \n",ACK.ack_state); } else { printf("luu email that bai \n"); strcpy(ACK.ack_state,"failed"); } //ACK length calculation //HEL.hello_len=strlen(HEL.hello_id)+strlen(HEL.mail_user)+sizeof(HEL.hello_detect); ACK.ack_len=strlen(ACK.ack_id)+sizeof(ACK.ack_detect)+strlen(ACK.client_mail)+strlen(ACK.ack_state)+4; //feedback lai client ban tin ack: int nsent; nsent=sendto(i,ACK.ack_id,11,0,(struct sockaddr*)&clientAddress,clientaddrlen); //ack_id if(nsent==-1) { printf("In socket-error when sending ack ID %d\n",i); perror("SEND"); close_fd = 1; } nsent=sendto(i,&ACK.ack_len,4,0,(struct sockaddr*)&clientAddress,clientaddrlen); //ack_len if(nsent==-1) { printf("In socket-error when sending ack len %d\n",i); perror("SEND"); close_fd = 1; } nsent=sendto(i,&ACK.ack_detect,4,0,(struct sockaddr*)&clientAddress,clientaddrlen); //ack_detect if(nsent==-1) { printf("In socket-error when sending ack detect %d\n",i); perror("SEND"); close_fd = 1; } strcpy(ACK.client_mail,mail_temp[dem]); //ack_mail -< error nsent=sendto(i,ACK.client_mail,50,0,(struct sockaddr*)&clientAddress,clientaddrlen); if(nsent==-1) { printf("In socket-error when sending back CLIENT MAIL %d\n",i); perror("SEND"); close_fd = 1; } printf("state chuan bi gui di la : %s \n",ACK.ack_state); nsent=sendto(i,ACK.ack_state,20,0,(struct sockaddr*)&clientAddress,clientaddrlen); //ack_state if(nsent==-1) { printf("In socket-error when sending ack_state %d\n",i); perror("SEND"); close_fd = 1; } printf("state vua gui di la : %s \n",ACK.ack_state); printf("successfully sent ACK bulletin to client\n"); //goto Round_Check; //int nsent = send(i,message2,strlen(message2),0); //end feedback /* else { close_fd = 1; }*/ printf("receive BYE bulletin \n"); //PROBLEM HERE? nrecv=recvfrom(i,BYE.bye_id,11,0,(struct sockaddr*)&clientAddress,&clientaddrlen); //bye_id if(nrecv==-1) { printf("received bye_id bulletin failed\n"); perror("RECEIVE"); exit(0); } nrecv=recvfrom(i,&BYE.bye_detect,4,0,(struct sockaddr*)&clientAddress,&clientaddrlen); //bye_detect if(nrecv==-1) { printf("received bye_id bulletin failed\n"); perror("RECEIVE"); exit(0); } close_fd=1; printf("remote client closed its socket\n"); goto close_socket; //thoat khoi checking FD_ISSET //-----------------------End of data processing-------------------------------- }//end if of FD_ISSET //}//end for }//end of else }//end do while while(1); }// ------------------end esle of DATA handling-------------------- //close(close_fd); close_socket: close(serverSocket); exit(0); }//end main
Probably there is something goes wrong with my select() function. I've tried to fix but they are all helpless.Code:#include <stdio.h> #include <string.h> #include <stdlib.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #define UDPPORT 5011 int main(int argc,char *argv[]) { //tao ban tin struct hello { char hello_id[11];//10 ky tu dientu-k53 + 1 ki tu ket thuc long int hello_len; //32bit long int hello_detect; char mail_user[50]; //mail user from client } HEL; HEL.hello_detect=0; strcpy(HEL.hello_id,"dientu-K53"); struct acknowledgement { char ack_id[11]; long int ack_len; long int ack_detect; char client_mail[50]; //tra ve mail user cho client char ack_state[20]; //trang thai "success" or "failed" } ACK; strcpy(ACK.ack_id,"dientu-K53"); ACK.ack_detect=1; struct bye { char bye_id[11]; long int bye_detect; } BYE; strcpy(BYE.bye_id,"dientu-K53"); BYE.bye_detect=2; //-------------ket thuc tao ban tin---------------------- int clientSocket=socket(PF_INET,SOCK_DGRAM,0); struct hostent *he; int check; //check return value of socket function if(clientSocket==-1) { perror("error making socket\n"); exit(1); } struct sockaddr_in serveraddr, clientaddr; int serveraddrlen=sizeof(serveraddr); serveraddr.sin_family=AF_INET; serveraddr.sin_port=htons(UDPPORT); serveraddr.sin_addr.s_addr=INADDR_ANY; he=gethostbyname(argv[1]); //-----------------------Data processing begin --------------------- printf("nhap email nguoi gui:\n"); int nsend; gets(HEL.mail_user); //verify the null int dem=strlen(HEL.mail_user); //chieu dai //HEL.mail_user[dem]='\0'; if(HEL.mail_user[dem]=='\0') printf("%d th la ki tu NULL\n",dem); //calculate len: HEL.hello_len=strlen(HEL.hello_id)+strlen(HEL.mail_user)+sizeof(HEL.hello_detect)+4; //mail truoc: nsend=sendto(clientSocket,HEL.mail_user,strlen(HEL.mail_user),0,(struct sockaddr *)&serveraddr,serveraddrlen); if(nsend==-1) { printf("send email user error\n"); perror("SEND"); exit(0); } printf("hello_len= %ld \n",HEL.hello_len); //send "hello" to server nsend=sendto(clientSocket,HEL.hello_id,11,0,(struct sockaddr *)&serveraddr,serveraddrlen); //hello_id if(nsend==-1) { printf("send hello_id error\n"); perror("SEND"); exit(0); } //PROBLEM HERE-them "&"truoc hello_len do truyen buffer nsend=sendto(clientSocket,&HEL.hello_len,4,0,(struct sockaddr *)&serveraddr,serveraddrlen); //hello_len if(nsend==-1) { printf("send hello_len error\n"); perror("SEND"); exit(0); } nsend=sendto(clientSocket,&HEL.hello_detect,4,0,(struct sockaddr *)&serveraddr,serveraddrlen); //hello_detect if(nsend==-1) { printf("send hello_detect error\n"); perror("SEND"); exit(0); }//PROBLEM HERE printf("Waiting for server reply\n"); //goto Round_Check; // ket thuc send hello //********************************************************* //nhan ACK & send BYE, dong socket printf("nhan ACK, send BYE,close client's corresponding socket\n"); int nrecv; nrecv=recvfrom(clientSocket,ACK.ack_id,11,0,(struct sockaddr *)&serveraddr,&serveraddrlen); //ack_id if(nrecv==-1) { printf("error when receiving ack_id \n"); perror("RECEIVE"); exit(0); } //hien thi truong nhan dang ack_id cua client: printf("truong nhan dang client= %s \n",ACK.ack_id); nrecv=recvfrom(clientSocket,&ACK.ack_len,4,0,(struct sockaddr *)&serveraddr,&serveraddrlen); //ack_len if(nrecv==-1) { printf("error when receiving ack_len \n"); perror("RECEIVE"); exit(0); } nrecv=recvfrom(clientSocket,&ACK.ack_detect,4,0,(struct sockaddr *)&serveraddr,&serveraddrlen); //ack_detect if(nrecv==-1) { printf("error when receiving ack_detect \n"); perror("RECEIVE"); exit(0); } nrecv=recvfrom(clientSocket,ACK.client_mail,sizeof(HEL.mail_user),0,(struct sockaddr *)&serveraddr,&serveraddrlen); //ack_mail if(nrecv==-1) { printf("error when receiving client_mail \n"); perror("RECEIVE"); exit(0); } nrecv=recvfrom(clientSocket,ACK.ack_state,20,0,(struct sockaddr *)&serveraddr,&serveraddrlen); //ack_state if(nrecv==-1) { printf("error when receiving ack_state \n"); perror("RECEIVE"); exit(0); } //hien thi truong trang thai ack_state: //khong can them ki tu NULL do luc dau send mail da co printf("luu tru email user tai server: %s \n",ACK.ack_state); //goto Round_Check; //**********************************Round2******************************** //send "BYE" back to server nsend=sendto(clientSocket,BYE.bye_id,11,0,(struct sockaddr *)&serveraddr,serveraddrlen); //bye_id if(nsend==-1) { printf("error occurrs when sending bye_id\n"); perror("SEND"); exit(0); } nsend=sendto(clientSocket,&BYE.bye_detect,4,0,(struct sockaddr *)&serveraddr,serveraddrlen); //bye_detect if(nsend==-1) { printf("error occurrs when sending bye_detect\n"); perror("SEND"); exit(0); } printf("send BYE to server successfully, gonna close socket\n"); //-----------------------Data processing end---------------------- close(clientSocket); exit(0); } //------end of main---------
Looking forward to your advices
