Subject: Re: [RFC v2 3/7] net: netfilter conntrack - add per-net functionality for SCTP protocol

From: Patrick McHardy <[email-masked]>
Date: Mon, 16 Mar 2009 16:35:11 +0100

Cyrill Gorcunov wrote:
> Module specific data moved into per-net site and being allocated/freed
> during net namespace creation/deletion.

> +#define ___PERNET_TO_DAT(i, j) \
> +	sn->sysctl_table[i].data = &sn->sctp_timeouts[j]
> +
> +	___PERNET_TO_DAT(0, SCTP_CONNTRACK_CLOSED);
> +	___PERNET_TO_DAT(1, SCTP_CONNTRACK_COOKIE_WAIT);
> +	___PERNET_TO_DAT(2, SCTP_CONNTRACK_COOKIE_ECHOED);
> +	___PERNET_TO_DAT(3, SCTP_CONNTRACK_ESTABLISHED);
> +	___PERNET_TO_DAT(4, SCTP_CONNTRACK_SHUTDOWN_SENT);
> +	___PERNET_TO_DAT(5, SCTP_CONNTRACK_SHUTDOWN_RECD);
> +	___PERNET_TO_DAT(6, SCTP_CONNTRACK_SHUTDOWN_ACK_SENT);
> +
> +#undef ___PERNET_TO_DAT
> +
> +	sn->sysctl_header = register_net_sysctl_table(net,
> +			nf_net_netfilter_sysctl_path, sn->sysctl_table);
> +	if (!sn->sysctl_header)
> +		goto out_free;
> +
> +#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
> +	sn->compat_sysctl_table = kmemdup(sctp_compat_sysctl_table,
> +			sizeof(sctp_compat_sysctl_table), GFP_KERNEL);
> +	if (!sn->compat_sysctl_table)
> +		goto out_sysctl;
> +
> +#define ___PERNET_TO_DAT(i, j) \
> +	sn->compat_sysctl_table[i].data = &sn->sctp_timeouts[j]
> +
> +	___PERNET_TO_DAT(0, SCTP_CONNTRACK_CLOSED);
> +	___PERNET_TO_DAT(1, SCTP_CONNTRACK_COOKIE_WAIT);
> +	___PERNET_TO_DAT(2, SCTP_CONNTRACK_COOKIE_ECHOED);
> +	___PERNET_TO_DAT(3, SCTP_CONNTRACK_ESTABLISHED);
> +	___PERNET_TO_DAT(4, SCTP_CONNTRACK_SHUTDOWN_SENT);
> +	___PERNET_TO_DAT(5, SCTP_CONNTRACK_SHUTDOWN_RECD);
> +	___PERNET_TO_DAT(6, SCTP_CONNTRACK_SHUTDOWN_ACK_SENT);
> +
> +#undef ___PERNET_TO_DAT

This is really ugly and is somewhat risky since those magic offsets need
to be kept in sync. Any chance (I don't have a suggestion currently) to
do this in a nicer way?