Re: [PATCH net-next v2 1/5] mpls: Use definition for reserved label checks

[ebiederm@xmission.com (Eric W. Biederman)]

Robert Shearman <rshearma@brocade.com> writes:

> In multiple locations there are checks for whether the label in hand
> is a reserved label or not using the arbritray value of 16. Factor
> this out into a #define for better maintainability and for
> documentation.

Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>

> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Signed-off-by: Robert Shearman <rshearma@brocade.com>
> ---
>  net/mpls/af_mpls.c  | 20 ++++++++++----------
>  net/mpls/internal.h |  1 +
>  2 files changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
> index db8a2ea..0d6763a 100644
> --- a/net/mpls/af_mpls.c
> +++ b/net/mpls/af_mpls.c
> @@ -276,7 +276,7 @@ static void mpls_notify_route(struct net *net, unsigned index,
>  	struct mpls_route *rt = new ? new : old;
>  	unsigned nlm_flags = (old && new) ? NLM_F_REPLACE : 0;
>  	/* Ignore reserved labels for now */
> -	if (rt && (index >= 16))
> +	if (rt && (index >= LABEL_FIRST_UNRESERVED))
>  		rtmsg_lfib(event, index, rt, nlh, net, portid, nlm_flags);
>  }
>  
> @@ -310,7 +310,7 @@ static unsigned find_free_label(struct net *net)
>  
>  	platform_label = rtnl_dereference(net->mpls.platform_label);
>  	platform_labels = net->mpls.platform_labels;
> -	for (index = 16; index < platform_labels; index++) {
> +	for (index = LABEL_FIRST_UNRESERVED; index < platform_labels; index++) {
>  		if (!rtnl_dereference(platform_label[index]))
>  			return index;
>  	}
> @@ -335,8 +335,8 @@ static int mpls_route_add(struct mpls_route_config *cfg)
>  		index = find_free_label(net);
>  	}
>  
> -	/* The first 16 labels are reserved, and may not be set */
> -	if (index < 16)
> +	/* Reserved labels may not be set */
> +	if (index < LABEL_FIRST_UNRESERVED)
>  		goto errout;
>  
>  	/* The full 20 bit range may not be supported. */
> @@ -413,8 +413,8 @@ static int mpls_route_del(struct mpls_route_config *cfg)
>  
>  	index = cfg->rc_label;
>  
> -	/* The first 16 labels are reserved, and may not be removed */
> -	if (index < 16)
> +	/* Reserved labels may not be removed */
> +	if (index < LABEL_FIRST_UNRESERVED)
>  		goto errout;
>  
>  	/* The full 20 bit range may not be supported */
> @@ -610,8 +610,8 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
>  					   &cfg->rc_label))
>  				goto errout;
>  
> -			/* The first 16 labels are reserved, and may not be set */
> -			if (cfg->rc_label < 16)
> +			/* Reserved labels may not be set */
> +			if (cfg->rc_label < LABEL_FIRST_UNRESERVED)
>  				goto errout;
>  
>  			break;
> @@ -736,8 +736,8 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
>  	ASSERT_RTNL();
>  
>  	index = cb->args[0];
> -	if (index < 16)
> -		index = 16;
> +	if (index < LABEL_FIRST_UNRESERVED)
> +		index = LABEL_FIRST_UNRESERVED;
>  
>  	platform_label = rtnl_dereference(net->mpls.platform_label);
>  	platform_labels = net->mpls.platform_labels;
> diff --git a/net/mpls/internal.h b/net/mpls/internal.h
> index fb6de92..5732283 100644
> --- a/net/mpls/internal.h
> +++ b/net/mpls/internal.h
> @@ -9,6 +9,7 @@
>  #define LABEL_GAL			13 /* RFC5586 */
>  #define LABEL_OAM_ALERT			14 /* RFC3429 */
>  #define LABEL_EXTENSION			15 /* RFC7274 */
> +#define LABEL_FIRST_UNRESERVED		16 /* RFC3032 */
>  
>  
>  struct mpls_shim_hdr {