Subject: Re: [PATCH v2 21/25] tcp: authopt: Add initial l3index support

From: David Ahern <[email-masked]>
Date: Tue, 2 Nov 2021 21:06:43 -0600

On 11/1/21 10:34 AM, Leonard Crestez wrote:
> @@ -584,10 +614,24 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
>  		return -EINVAL;
>  	err = tcp_authopt_alg_require(alg);
>  	if (err)
>  		return err;
>  
> +	/* check ifindex is valid (zero is always valid) */
> +	if (opt.flags & TCP_AUTHOPT_KEY_IFINDEX && opt.ifindex) {
> +		struct net_device *dev;
> +
> +		rcu_read_lock();
> +		dev = dev_get_by_index_rcu(sock_net(sk), opt.ifindex);
> +		if (dev && netif_is_l3_master(dev))
> +			l3index = dev->ifindex;
> +		rcu_read_unlock();

rcu_read_lock()... rcu_read_unlock() can be replaced with
netif_index_is_l3_master(...)