UDP/TCP combination problem

FaresH · 02-26-2009, 05:43 AM

Hi,

I want to send ten integers from 0-9 from a server to a client.
Both sides have a tcp and udp sockets.
The even numbers, 0 included, will be sent thru the tcp.
The odd numbers will be sent thru the udp.

This is what I wrote but it gives me a bad address error by the recvfrom on the client side.

Client side

PHP Code:



 
           struct sockaddr_in server ; 
 
    server.sin_family = AF_INET; 
        inet_aton(argv[1],&(server.sin_addr)); 
        server.sin_port = htons(atoi(argv[3])); 
 
    printf("UDP: Server Socket\n"); 
    if( (udp_socket = socket (AF_INET,SOCK_DGRAM,0)) < 0 ){ 
        somethingIsWrong("UDP", SOCKERR); 
    } 
 
    printf("UDP: Connect\n"); 
    if ((connect(udp_socket, (struct sockaddr*)&server, sizeof(server))) < 0 ){ 
        somethingIsWrong("UDP", CONCTERR); 
    } 
 
    printf("TCP: Connect\n");  
    if( (tcp_socket = tcp_connect(argv[1], atoi(argv[2]))) < 0 ){  
        somethingIsWrong("TCP", SOCKERR);  
    } 
 
    for( i=0 ; i < 10 ; i+=2 ){ 
        if( (cur_received= tcp_receive(tcp_socket, buf, BUFFSIZE, 0 )) < 0 ){  
            somethingIsWrong("TCP", READERR);  
        } 
        printf("TCP- %i ", atoi(&buf[0])); 
        i++; 
        if( (cur_received = recvfrom(udp_socket, &buf, sizeof(buf),0,  
                (struct sockaddr *)&server, (socklen_t *) sizeof(server))) < 0 ){ 
            somethingIsWrong("UDP", READERR);  
        } 
        printf("UDP- %i ", atoi(&buf[0])); 
    } 
 
        printf("\n");

Server

PHP Code:



 
        struct sockaddr_in server ; 
    struct sockaddr_in client ; 
 
    server.sin_family = AF_INET; 
    server.sin_addr.s_addr = INADDR_ANY; 
    server.sin_port = htons(atoi(argv[2])); 
 
    printf("Udp: Socket\n"); 
 
    if( (server_udp = socket (AF_INET,SOCK_DGRAM,0)) < 0){ 
        somethingIsWrong("UDP", SOCKERR); 
    } 
 
    printf("Bind UDP\n"); 
    if(bind (server_udp, (struct sockaddr*)&server, sizeof(server))==-1){ 
        somethingIsWrong("UDP", BINDERR); 
    } 
 
    printf("Establish tcp server\n"); 
        // tcp_establish creates socket, bind it to port=argv[1] and listens 
    if( (server_tcp = tcp_establish(atoi(argv[1]), BACKLOG )) < 0 ){ 
        somethingIsWrong("TCP", SOCKERR); 
    } 
 
    printf("New Client\n"); 
        // accepts new clients 
    if( (client_tcp = tcp_get_connection(server_tcp, NULL )) < 0 ){ 
        somethingIsWrong("TCP", ACCEPTERR); 
    } 
 
    for( i=0 ; i < 10 ; i++ ){ 
        printf("%i ", i); 
        memcpy(buf, &i, sizeof(u_int)); 
        if( tcp_send(client_tcp, buf, sizeof(int), 0) < 0 ){  
            somethingIsWrong("TCP", SENDERR);  
        } 
        i++; 
        memcpy(buf, &i, sizeof(u_int)); 
        printf("%i ", i); 
        if( sendto(server_udp, buf, BUFFSIZE, 0, (struct sockaddr *) &client,  sizeof(client) ) < 0 ){  
            somethingIsWrong("UDP", SENDERR);  
        } 
    }     
 
    printf("\n");

Any idea how to solve this problem ?
I know that a tcp and udp can be on the same port, since Ip header makes it clear what protocol is being used.
But I am running the client and server on the same pc. Maybe thats the problem that we have two udp and two tcp on the same port. Can that be it ? If so how do I solve this ?

Thanks.

dwhitney67 · 02-26-2009, 07:00 AM

FaresH,

I understand you require help with your application, however posting your query on multiple forums (the other being the Ubuntu Programming Forum) just adds clutter to the WWW.

Anyhow, should anyone else come across this thread, click on this link to see my response to FaresH's question.

FaresH · 02-26-2009, 09:08 AM

Whats wrong with multi-feedbacks ?

Anyhow I solved my problem a few minutes ago, I just came to say that I solved it.
The error was not in the design, it was in the recvfrom.

recvfrom requires that the last parameter must be a pointer. Unlike in sendto. I am assuming because recvfrom updates/changes something in the struct sockaddr_in client. Maybe the size changes.
And I was giving it sizeof(client). So it couldn't update it.
So the second time recvfrom was called, it gave me a bad address.