linux-kernel - Re: [PATCH net-next v1 1/1] br_netfilter: namespace bridge netfilter sysctls

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Message-ID: <20190610174136.p3fbcbn33en5bb7f@salvia>
Date:   Mon, 10 Jun 2019 19:41:36 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     Christian Brauner <christian@...uner.io>
Cc:     davem@...emloft.net, netdev@...r.kernel.org,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        bridge@...ts.linux-foundation.org, tyhicks@...onical.com,
        kadlec@...ckhole.kfki.hu, fw@...len.de, roopa@...ulusnetworks.com,
        nikolay@...ulusnetworks.com, linux-kernel@...r.kernel.org,
        richardrose@...gle.com, vapier@...omium.org, bhthompson@...gle.com,
        smbarber@...omium.org, joelhockey@...omium.org,
        ueberall@...menzentrisch.de
Subject: Re: [PATCH net-next v1 1/1] br_netfilter: namespace bridge netfilter
 sysctls

Thanks for updating this patch to use struct brnf_net.

A few comments below.

On Sun, Jun 09, 2019 at 06:23:04PM +0200, Christian Brauner wrote:
[...]
> diff --git a/include/net/netfilter/br_netfilter.h b/include/net/netfilter/br_netfilter.h
> index 89808ce293c4..302fcd3aade2 100644
> --- a/include/net/netfilter/br_netfilter.h
> +++ b/include/net/netfilter/br_netfilter.h
> @@ -85,17 +82,42 @@ static inline __be16 vlan_proto(const struct sk_buff *skb)
>  		return 0;
>  }
>  
> -#define IS_VLAN_IP(skb) \
> -	(vlan_proto(skb) == htons(ETH_P_IP) && \
> -	 brnf_filter_vlan_tagged)
> +static inline bool is_vlan_ip(const struct sk_buff *skb, const struct net *net)
> +{

I like this conversion from macro to static inline a lot.

But if you let me ask for one more change, would you split this in two
patches? One to replace #defines by static inline.

Then, second patch introduces the sysctl update you need.

It will make it easier for me to review.

[...]
> +static inline bool is_vlan_ipv6(const struct sk_buff *skb,
> +				const struct net *net)
> +{
> +#ifdef CONFIG_SYSCTL

Probably we can reduce #ifdef pollution a bit if you always add
'filter_vlan_tagged' and other fields to the brnf_net structure. No
matter if CONFIG_SYSCTL is set on or off. I think it's worth consuming
a bit more memory to simplify this code, so both CONFIG_SYSCTL=y and
CONFIG_SYSCTL=n run the same codepath.

Most vendors will just turn on to CONFIG_SYSCTL=y, and I don't think
it's worth the extra code for the CONFIG_SYSCTL=n case.

> +	struct brnf_net *brnet = net_generic(net, brnf_net_id);
> +
> +	return (vlan_proto(skb) == htons(ETH_P_IPV6) &&
> +		brnet->filter_vlan_tagged);
> +#else
> +	return (vlan_proto(skb) == htons(ETH_P_IPV6));

BTW, I think parens are not needed, ie.

	return vlan_proto(skb) == htons(ETH_P_IPV6);

should be fine?

Thanks!