Subject: Re: [PATCH v6 2/3] sctp: add check rto_min and rto_max in sysctl

From: Vlad Yasevich <[email-masked]>
Date: Tue, 10 Dec 2013 09:34:14 -0500

On 12/09/2013 09:46 PM, Wang Weidong wrote:
> rto_min should be smaller than rto_max while rto_max should be larger
> than rto_min. Add two proc_handler for the checking.
> 
> Suggested-by: Vlad Yasevich <[email-masked]>
> Signed-off-by: Wang Weidong <[email-masked]>
> ---
>  net/sctp/sysctl.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 65 insertions(+), 4 deletions(-)
> 
> diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
> index 6b36561..ed4ec89 100644
> --- a/net/sctp/sysctl.c
> +++ b/net/sctp/sysctl.c
> @@ -61,6 +61,13 @@ static int proc_sctp_do_hmac_alg(struct ctl_table *ctl,
>  				void __user *buffer, size_t *lenp,
>  
>  				loff_t *ppos);
> +static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
> +				void __user *buffer, size_t *lenp,
> +				loff_t *ppos);
> +static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
> +				void __user *buffer, size_t *lenp,
> +				loff_t *ppos);
> +
>  static struct ctl_table sctp_table[] = {
>  	{
>  		.procname	= "sctp_mem",
> @@ -102,17 +109,17 @@ static struct ctl_table sctp_net_table[] = {
>  		.data		= &init_net.sctp.rto_min,
>  		.maxlen		= sizeof(unsigned int),
>  		.mode		= 0644,
> -		.proc_handler	= proc_dointvec_minmax,
> +		.proc_handler	= proc_sctp_do_rto_min,
>  		.extra1         = &one,
> -		.extra2         = &timer_max
> +		.extra2         = &init_net.sctp.rto_max
>  	},
>  	{
>  		.procname	= "rto_max",
>  		.data		= &init_net.sctp.rto_max,
>  		.maxlen		= sizeof(unsigned int),
>  		.mode		= 0644,
> -		.proc_handler	= proc_dointvec_minmax,
> -		.extra1         = &one,
> +		.proc_handler	= proc_sctp_do_rto_max,
> +		.extra1         = &init_net.sctp.rto_min,
>  		.extra2         = &timer_max
>  	},
>  	{
> @@ -342,6 +349,60 @@ static int proc_sctp_do_hmac_alg(struct ctl_table *ctl,
>  	return ret;
>  }
>  
> +static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
> +				void __user*buffer, size_t *lenp,
                                         ^^^^
Please put a space before the '*'.

> +				loff_t *ppos)
> +{
> +	struct net *net = current->nsproxy->net_ns;
> +	int new_value;
> +	struct ctl_table tbl;
> +	unsigned int min = *(unsigned int *) ctl->extra1;
> +	unsigned int max = *(unsigned int *) ctl->extra2;
> +	int ret;
> +
> +	memset(&tbl, 0, sizeof(struct ctl_table));
> +	tbl.maxlen = sizeof(unsigned int);
> +
> +	if (write)
> +		tbl.data = &new_value;
> +	else
> +		tbl.data = &net->sctp.rto_min;
> +	ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
> +	if (write) {
> +		if (ret || new_value > max || new_value < min)
> +			return -EINVAL;
> +		net->sctp.rto_min = new_value;
> +	}
> +	return ret;
> +}
> +
> +static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
> +				void __user*buffer, size_t *lenp,
                                         ^^^^
Please put a space after the before the '*'.

Thanks
-vlad

> +				loff_t *ppos)
> +{
> +	struct net *net = current->nsproxy->net_ns;
> +	int new_value;
> +	struct ctl_table tbl;
> +	unsigned int min = *(unsigned int *) ctl->extra1;
> +	unsigned int max = *(unsigned int *) ctl->extra2;
> +	int ret;
> +
> +	memset(&tbl, 0, sizeof(struct ctl_table));
> +	tbl.maxlen = sizeof(unsigned int);
> +
> +	if (write)
> +		tbl.data = &new_value;
> +	else
> +		tbl.data = &net->sctp.rto_max;
> +	ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
> +	if (write) {
> +                if (ret || new_value > max || new_value < min)
> +			return -EINVAL;
> +		net->sctp.rto_max = new_value;
> +	}
> +	return ret;
> +}
> +
>  int sctp_sysctl_net_register(struct net *net)
>  {
>  	struct ctl_table *table;
>