Is there a kernel module that returns exactly what a simple 'ifconfig' does?

kernel-module, linux, network-interface

Solution

You can get all of that information through the `struct net_device` one way or another. As Albert Veli said, you can get this `struct net_device` pointer using `__dev_get_by_name()`.

If you tell us what information you need specifically we might even be able to point you to the correct fields.

Finding the MAC address is fairly simple:

struct net_device *dev = __dev_get_by_name("eth0");
dev->dev_addr; // is the MAC address
dev->stats.rx_dropped; // RX dropped packets. (stats has more statistics)

Finding the IP address is rather harder, but not impossible:

struct in_device *in_dev = rcu_dereference(dev->ip_ptr);
// in_dev has a list of IP addresses (because an interface can have multiple)
struct in_ifaddr *ifap;
for (ifap = in_dev->ifa_list; ifap != NULL;
         ifap = ifap->ifa_next) {
    ifap->ifa_address; // is the IPv4 address
}

(None of this was compile tested, so typos are possible.)

Problem

I'm writing a kernel module that needs information about the local machine's interfaces just like the ones retuned by a simple 'ifconfig' command, I've searched a lot for it, but couldn't find anything

Original source