Linux getting all network interface names

Question

I need to collect all the interface names, even the ones that aren't up at the moment. Like ifconfig -a.

getifaddrs() is iterating through same interface name multiple times. How can I collect all the interface names just once using getifaddrs()?

Answer 1

You could check which entries from getifaddrs belong to the AF_PACKET family. On my system that seems to list all interfaces:

struct ifaddrs *addrs,*tmp;

getifaddrs(&addrs);
tmp = addrs;

while (tmp)
{
    if (tmp->ifa_addr && tmp->ifa_addr->sa_family == AF_PACKET)
        printf("%s\n", tmp->ifa_name);

    tmp = tmp->ifa_next;
}

freeifaddrs(addrs);