netdev - Re: [PATCH net-next] net: Export net->ipv6.sysctl.ip_nonlocal

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Date:   Tue, 27 Mar 2018 15:44:20 +0300
From:   Kirill Tkhai <ktkhai@...tuozzo.com>
To:     davem@...emloft.net, yoshfuji@...ux-ipv6.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH net-next] net: Export net->ipv6.sysctl.ip_nonlocal_bind to
 /proc

Please, ignore this.

Thanks,
Kirill

On 27.03.2018 14:24, Kirill Tkhai wrote:
> Currenly, this parameter can be configured via sysctl
> only. But sysctl is considered as depricated interface
> (man 2 sysctl), and it only can applied to current's net
> namespace (this requires to do setns() to change it in
> not current's net ns).
> 
> So, let's export the parameter to /proc in standard way,
> and this allows to access another process namespace
> via /proc/[pid]/net/ip6_nonlocal_bind.
> 
> Signed-off-by: Kirill Tkhai <ktkhai@...tuozzo.com>
> ---
>  net/ipv6/proc.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
> 
> diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
> index 6e57028d2e91..2d0aa59c2d0d 100644
> --- a/net/ipv6/proc.c
> +++ b/net/ipv6/proc.c
> @@ -312,6 +312,47 @@ int snmp6_unregister_dev(struct inet6_dev *idev)
>  	return 0;
>  }
>  
> +static int nonlocal_bind_show(struct seq_file *seq, void *v)
> +{
> +	struct net *net = seq->private;
> +
> +	seq_printf(seq, "%d\n", !!net->ipv6.sysctl.ip_nonlocal_bind);
> +	return 0;
> +}
> +
> +static int open_nonlocal_bind(struct inode *inode, struct file *file)
> +{
> +	return single_open_net(inode, file, nonlocal_bind_show);
> +}
> +
> +static ssize_t write_nonlocal_bind(struct file *file, const char __user *ubuf,
> +				   size_t count, loff_t *ppos)
> +{
> +	struct net *net = ((struct seq_file *)file->private_data)->private;
> +	char buf[3];
> +
> +	if (*ppos || count <= 0 || count > sizeof(buf))
> +		return -EINVAL;
> +
> +	if (copy_from_user(buf, ubuf, count))
> +		return -EFAULT;
> +	buf[0] -= '0';
> +	if ((count == 3 && buf[2] != '\0') ||
> +	    (count >= 2 && buf[1] != '\n') ||
> +	    (buf[0] != 0 && buf[0] != 1))
> +		return -EINVAL;
> +
> +	net->ipv6.sysctl.ip_nonlocal_bind = buf[0];
> +	return count;
> +}
> +
> +static const struct file_operations nonlocal_bind_ops = {
> +	.open	= open_nonlocal_bind,
> +	.read	= seq_read,
> +	.write	= write_nonlocal_bind,
> +	.release = single_release_net,
> +};
> +
>  static int __net_init ipv6_proc_init_net(struct net *net)
>  {
>  	if (!proc_create("sockstat6", 0444, net->proc_net,
> @@ -321,12 +362,18 @@ static int __net_init ipv6_proc_init_net(struct net *net)
>  	if (!proc_create("snmp6", 0444, net->proc_net, &snmp6_seq_fops))
>  		goto proc_snmp6_fail;
>  
> +        if (!proc_create_data("ip6_nonlocal_bind", 0644,
> +			       net->proc_net, &nonlocal_bind_ops, net))
> +		goto proc_bind_fail;
> +
>  	net->mib.proc_net_devsnmp6 = proc_mkdir("dev_snmp6", net->proc_net);
>  	if (!net->mib.proc_net_devsnmp6)
>  		goto proc_dev_snmp6_fail;
>  	return 0;
>  
>  proc_dev_snmp6_fail:
> +	remove_proc_entry("ip6_nonlocal_bind", net->proc_net);
> +proc_bind_fail:
>  	remove_proc_entry("snmp6", net->proc_net);
>  proc_snmp6_fail:
>  	remove_proc_entry("sockstat6", net->proc_net);
> @@ -337,6 +384,7 @@ static void __net_exit ipv6_proc_exit_net(struct net *net)
>  {
>  	remove_proc_entry("sockstat6", net->proc_net);
>  	remove_proc_entry("dev_snmp6", net->proc_net);
> +	remove_proc_entry("ip6_nonlocal_bind", net->proc_net);
>  	remove_proc_entry("snmp6", net->proc_net);
>  }
>  
>