static bool validate_ipv4_net_dev(struct net_device *net_dev,
				  const struct sockaddr_in *dst_addr,
				  const struct sockaddr_in *src_addr)
{
	__be32 daddr = dst_addr->sin_addr.s_addr,
	       saddr = src_addr->sin_addr.s_addr;
	struct fib_result res;
	struct flowi4 fl4;
	int err;
	bool ret;

	if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
	    ipv4_is_lbcast(daddr) || ipv4_is_zeronet(saddr) ||
	    ipv4_is_zeronet(daddr) || ipv4_is_loopback(daddr) ||
	    ipv4_is_loopback(saddr))
		return false;

	memset(&fl4, 0, sizeof(fl4));
	fl4.flowi4_iif = net_dev->ifindex;
	fl4.daddr = daddr;
	fl4.saddr = saddr;

	rcu_read_lock();
	err = fib_lookup(dev_net(net_dev), &fl4, &res, 0);
	ret = err == 0 && FIB_RES_DEV(res) == net_dev;
	rcu_read_unlock();

	return ret;
}
Unknown