CODEWITHSUNDEEP
c++socketsnetwork-programmingtcp
AL1ve1T
AL1ve1T

Reputation: 115

c++ address family not supported by protocol

I write a method, that creates a socket, connect it to the endpoint, and then returns its descriptor:

static int open_socket(const char* host, unsigned short port)
        {
            #ifdef USE_IPV4
            struct hostent* _hostent;
            struct sockaddr_in _sockaddr_in;

            // Variables
            size_t sockaddr_len;
            int sock_family;
            int sock_type;
            int sock_protocol;
            int sockfd;

            _hostent = gethostbyname(host);
            if (_hostent == (struct hostent*) 0)
            {
                // Not Found
            }

            _sockaddr_in.sin_family = AF_INET;
            sock_family = AF_INET;
            sock_type = SOCK_STREAM;
            sock_protocol = IPPROTO_TCP;
            sockaddr_len = sizeof(_sockaddr_in);
            (void*) memmove(&_sockaddr_in, _hostent->h_addr, _hostent->h_length);
            _sockaddr_in.sin_port = htons(port);

            // Now create socket
            sockfd = socket(sock_family, sock_type, sock_protocol);
            if (sockfd < 0)
            {
                // "Internal Error"
            }
            if (connect(sockfd, (struct sockaddr*) &_sockaddr_in, sockaddr_len) < 0)
            {
                std::cerr << strerror(errno) << std::endl;
                std::cerr << "Endpoint is unavailable" << std::endl;
                return 0;
                // "Unavailable"
            }

            return sockfd;

            #endif
        }

The error occures when i try to connect socket. strerror(errno) returns "Address family not supported by protocol". I cannot figure out why it happens, because in other samples AF_INET fine works with IPPROTO_TCP

Upvotes: 1

Views: 2172

Answers (1)

user7860670
user7860670

Reputation: 37607

You need to store the address in sockaddr_in::sin_addr instead. You are overwriting the entire struct (starting from the sin_family) when you call memmove(&_sockaddr_in, ...).

Upvotes: 1

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