클라이언트가 BROADCAST UDP 서버에서 메시지를 수신 할 수 없습니다. (Winsock)

Question

나는 클라이언트 서버 UDP 응용 프로그램을 개발했습니다. Server UDP 소켓은 BROADCAST UDP 소켓으로 설정됩니다. 양측 코드가 오류를 생성하지는 않지만 BROADCAST UDP SERVER Side에서 보낸 메시지는 클라이언트 측에서 수신되지 않습니다. 친절하게도 내 코드를보고, 알아낼 수없는 실수가 있음을 알고 있습니다.

서버 :

#define PORT 8888 //The port on which to listen for incoming data 

int main() 
{ 

SOCKET s; 
struct sockaddr_in serverSocket, clientSocket; 

char receiveBuffer[1000]; 
//int receiveBufferLength=1000; 
int clientSocketLength; 
int recv_len; 

clientSocketLength = sizeof(clientSocket) ; 

WSADATA wsa; 
//Initialise winsock 
printf("\nInitialising Winsock..."); 
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0) 
{ 
    printf("Failed. Error Code : %d",WSAGetLastError()); 
    exit(EXIT_FAILURE); 
} 
printf("Socket Initialised.\n"); 

//Create a socket 
if((s = socket(AF_INET , SOCK_DGRAM , 0)) == INVALID_SOCKET) 
{ 
    printf("Could not create socket : %d" , WSAGetLastError()); 
} 
printf("Socket created.\n"); 

//Prepare the sockaddr_in structure 
serverSocket.sin_family = AF_INET; 
serverSocket.sin_addr.s_addr = INADDR_ANY; 
serverSocket.sin_port = htons(PORT); 

int broadcast =1; 


if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, (char*) &broadcast, sizeof(broadcast)) < 0) { 
    //close(sock); 
    printf("Error in setting broadcast option"); 
} 
//Bind 
if(bind(s ,(struct sockaddr *)&serverSocket , sizeof(serverSocket)) == SOCKET_ERROR) 
{ 
    printf("\nBind failed with error code : %d" , WSAGetLastError()); 
    exit(EXIT_FAILURE); 
} 
printf("Bind done\n\n"); 

//keep listening for data 


    printf("\n\t\t\tWaiting for data...\n"); 
    fflush(stdout); 
    //receiveBuffer[2000]=NULL; 

    if((recv_len = recvfrom(s, receiveBuffer, 1000, 0, (struct sockaddr *) &clientSocket, &clientSocketLength)) == SOCKET_ERROR) 
    { 
     printf("\n\nrecvfrom() failed with error code : %d" , WSAGetLastError()); 
     //exit(EXIT_FAILURE); 
     while(1); 
    } 

    //print details of the client/peer and the data received 
    printf("\n\nReceived packet from %s:%d\n", inet_ntoa(clientSocket.sin_addr), ntohs(clientSocket.sin_port)); 
    printf("\nClient Says: "); 
     printf(receiveBuffer,recv_len); 

    serverSocket.sin_addr.s_addr = INADDR_BROADCAST; 
    //now reply the client with the same data 
    if (sendto(s, receiveBuffer, recv_len, 0, (struct sockaddr*) &serverSocket, sizeof(serverSocket)) == SOCKET_ERROR) 
    { 
     printf("\nsendto() failed with error code : %d" , WSAGetLastError()); 
     // exit(EXIT_FAILURE); 
     while(1); 
    } 
    else 
     printf("\nMessage Sent Back to Client"); 
    while(1); 



closesocket(s); 
WSACleanup(); 
return 0; 

} 

CLIENT :

#define PORT 8888 //The port on which to listen for incoming data 
#define SERVER "127.0.0.1" //ip address of udp server 
//#define PORT 8888 //The port on which to listen for incoming data 

int main(void) 
{ 
struct sockaddr_in connectedSocket; 

int s; 
int length=sizeof(connectedSocket); 

char receiveBuffer[1000]; 
char message[1000]; 

//clear the buffer by filling null, it might have previously received data 
memset(receiveBuffer,'\0', 1000); 

WSADATA wsa; 
//Initialise winsock 
printf("\nInitialising Winsock...\n"); 
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0) 
{ 
    printf("\nFailed. Error Code : %d",WSAGetLastError()); 
    exit(EXIT_FAILURE); 
} 
printf("\n.........Initialised.\n"); 


//create socket 
if ((s=socket(AF_INET, SOCK_DGRAM, 0)) == SOCKET_ERROR) 
{ 
    printf("\n\nsocket() failed with error code : %d" , WSAGetLastError()); 
    exit(EXIT_FAILURE); 
} 


//setup address structure 
memset((char *) &connectedSocket, 0, sizeof(connectedSocket)); 
connectedSocket.sin_family = AF_INET; 
connectedSocket.sin_port = htons(PORT); 
//connectedSocket.sin_port = INADDR_BROADCAST; 
connectedSocket.sin_addr.S_un.S_addr = inet_addr(SERVER); 

printf("\n\n\nEnter message : "); 
    gets(message); 

    //send the message 
    if (sendto(s, message,sizeof(message) , 0 , (struct sockaddr *) &connectedSocket, sizeof(connectedSocket)) == SOCKET_ERROR) 
    { 
     printf("\nsendto() failed with error code : %d" , WSAGetLastError()); 
     exit(EXIT_FAILURE); 
    } 

     printf("\nMessage Successfully sent to Server"); 
     // fflush(stdout); 

    if (recvfrom(s, receiveBuffer, 1000, 0, (struct sockaddr *) &connectedSocket,&length) == SOCKET_ERROR) 
    { 
     printf("\nrecvfrom() failed with error code : %d" , WSAGetLastError()); 
     exit(EXIT_FAILURE); 
     while(1); 
    } 

    printf("\nServer Says : "); 
    printf(receiveBuffer,sizeof(receiveBuffer)); 

    while(1); 

closesocket(s); 
WSACleanup(); 

return 0; 

}

Answer 1

당신은 serverSocket에 다시 클라이언트로 응답을 보내는 정말 도움이 필요합니다. 메시지를 수신 한 clientsocket이 이미 있습니다.이 메시지를 사용하여 서버에서 클라이언트로 메시지를 다시 보냅니다.

제거 ...

serverSocket.sin_addr.s_addr = INADDR_BROADCAST; 

변경 ...

if (sendto(s, receiveBuffer, recv_len, 0, (struct sockaddr*) &serverSocket, sizeof(serverSocket)) == SOCKET_ERROR) 

if (sendto(s, receiveBuffer, recv_len, 0, (struct sockaddr*) &clientSocket, sizeof(clientSocket)) == SOCKET_ERROR) 

에 이제 작동합니다.