Re: [PATCH net-next v2 2/8] netfilter: add API to manage NAT helpers.

[Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>]

On Sat, Apr 13, 2019 at 08:17:10PM -0300, Flavio Leitner wrote:
[...]
> +void nf_nat_helper_put(struct nf_conntrack_helper *helper)
> +{
> +	struct nf_conntrack_nat_helper *nat;
> +
> +	nat = nf_conntrack_nat_helper_find(helper->nat_mod_name);
> +	BUG_ON(nat == NULL);

We've been trying to avoid BUG_ON() in many spots recently. Could you
turn this into... ?

        if (WARN_ON(!nat))
                return;

> +	module_put(nat->module);
> +}
> +EXPORT_SYMBOL_GPL(nf_nat_helper_put);
> +
>  struct nf_conn_help *
>  nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp)
>  {
> @@ -430,6 +502,10 @@ void nf_ct_helper_init(struct nf_conntrack_helper *helper,
>  	helper->help = help;
>  	helper->from_nlattr = from_nlattr;
>  	helper->me = module;
> +	helper->nat_mod_name[0] = '\0';
> +	if (name)
> +		snprintf(helper->nat_mod_name, sizeof(helper->nat_mod_name),
> +			 NF_NAT_HELPER_PREFIX"%s", name);
>  
>  	if (spec_port == default_port)
>  		snprintf(helper->name, sizeof(helper->name), "%s", name);
> @@ -466,6 +542,26 @@ void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *helper,
>  }
>  EXPORT_SYMBOL_GPL(nf_conntrack_helpers_unregister);
>  
> +void nf_nat_helper_register(struct nf_conntrack_nat_helper *nat)
> +{
> +	BUG_ON(nat->module == NULL);

Same here.

> +
> +	mutex_lock(&nf_ct_nat_helpers_mutex);
> +	list_add_rcu(&nat->list, &nf_ct_nat_helpers);
> +	mutex_unlock(&nf_ct_nat_helpers_mutex);
> +}
> +EXPORT_SYMBOL_GPL(nf_nat_helper_register);
> +
> +void nf_nat_helper_unregister(struct nf_conntrack_nat_helper *nat)
> +{
> +	BUG_ON(nat->module == NULL);

And here.

Thanks.