CODEWITHSUNDEEP
c++sockets
nihirus
nihirus

Reputation: 191

C++ Server Connection Issue

Firstly, the code I will share is the basis of my code(found it in another site, open source), I added functions and threads later to improve.

In the office, we have local network and another 3 computer cannot connect to my server. Especially have a look at that line. 26010 is random port number that I want to listen. According to data I found in the other topics, NULL and 127.0.0.1 are the localhost ip.I tried my own ip number instead of NULL, but it didn't work. I can send data from my client code to other computers, but can't get any connections.

Code is listening connections properly, and can get info if I open another 3 terminal and try to connect it from my computer through my client code. How to fix that?

Thanks in advance.

status = getaddrinfo(NULL, "26010", &host_info, &host_info_list);

int main()
{

    int status;
    struct addrinfo host_info;       // The struct that getaddrinfo() fills up with data.
    struct addrinfo *host_info_list; // Pointer to the to the linked list of host_info's.

    memset(&host_info, 0, sizeof host_info);

    std::cout << "Setting up the structs..."  << std::endl;

    host_info.ai_family = AF_UNSPEC;     // IP version not specified. Can be both.
    host_info.ai_socktype = SOCK_STREAM; // Use SOCK_STREAM for TCP or SOCK_DGRAM for UDP.
    host_info.ai_flags = AI_PASSIVE;     

    **status = getaddrinfo(NULL, "26010", &host_info, &host_info_list);**
    // getaddrinfo returns 0 on succes, or some other value when an error occured.
    // (translated into human readable text by the gai_gai_strerror function).
    if (status != 0)  std::cout << "getaddrinfo error" << gai_strerror(status) ;


    std::cout << "Creating a socket..."  << std::endl;
    int socketfd ; // The socket descripter
    socketfd = socket(host_info_list->ai_family, host_info_list->ai_socktype,
                      host_info_list->ai_protocol);
    if (socketfd == -1)  std::cout << "socket error " ;

    std::cout << "Binding socket..."  << std::endl;

    int yes = 1;
    status = setsockopt(socketfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
    status = bind(socketfd, host_info_list->ai_addr, host_info_list->ai_addrlen);
    if (status == -1)  std::cout << "bind error" << std::endl ;

    std::cout << "Listen()ing for connections..."  << std::endl;
    status =  listen(socketfd, 5);
    if (status == -1)  std::cout << "listen error" << std::endl ;


    int new_sd;
    struct sockaddr_storage their_addr;
    socklen_t addr_size = sizeof(their_addr);
    new_sd = accept(socketfd, (struct sockaddr *)&their_addr, &addr_size);
    if (new_sd == -1)
    {
        std::cout << "listen error" << std::endl ;
    }
    else
    {
        std::cout << "Connection accepted. Using new socketfd : "  <<  new_sd << std::endl;
    }


    std::cout << "Waiting to recieve data..."  << std::endl;
    ssize_t bytes_recieved;
    char incomming_data_buffer[1000];
    bytes_recieved = recv(new_sd, incomming_data_buffer,1000, 0);
    // If no data arrives, the program will just wait here until some data arrives.
    ...


    std::cout << "send()ing back a message..."  << std::endl;     
return 0 ;
}

Upvotes: 0

Views: 415

Answers (1)

Guillaume
Guillaume

Reputation: 2054

Your problem is your call to getaddrinfo(). This function returns information in the host_info_list member. What you're reading is the hint (host_info) which is not changed by getaddrinfo(). You would need to use host_info_list to read the what's returned by getaddrinfo. You never use it and you never free it (by calling freeaddrinfo).

I am not sure why you'd want to use getaddrinfo() to listen for connection. You can just build the sockaddr yourself. It's easy:

struct sockaddr_in listenAddr;
memset(&listenAddr, 0, sizeof(listenAddr));
/* IPv4 address */
listenAddr.sin_family = AF_INET;
/* your port number */
listenAddr.sin_port = htons(26010);
/* listen on all interfaces */
listenAddr.sin_addr.s_addr = htonl(INADDR_ANY);

/* TCP socket */
socketfd = socket(PF_INET, SOCK_STREAM, 0);

/* your error code, omitted here */

status = bind(SocketFD,(struct sockaddr *) &listenAddr, sizeof(listenAddr))

Upvotes: 1

Related Questions