How do I dynamically bind a socket to only one network interface?

Question

Currently I do the following to listen on any available port on all interfaces:

// hints struct for the getaddrinfo call
struct addrinfo hints, *res;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;

// Fill in addrinfo with getaddrinfo
if (getaddrinfo(NULL, "0", &hints, &res) != 0) {
    cerr << "Couldn't getaddrinfo." << endl;
    exit(-1);
}

I would like to dynamically bind to only one interface, the non-loopback interface of the system.

How would I go about doing this?

Answer 1

Take a look at SO_BINDTODEVICE. Tuxology has a good description of this