mpls: Use definition for reserved label checks

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.

Signed-off-by: Robert Shearman <rshearma@brocade.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 13 insertions, 10 deletions

diff --git a/include/uapi/linux/mpls.h b/include/uapi/linux/mpls.h
index 139d4dd1cab8..24a6cb1aec86 100644
--- a/include/uapi/linux/mpls.h
+++ b/include/uapi/linux/mpls.h
@@ -41,4 +41,6 @@ struct mpls_label {
 #define MPLS_LABEL_OAMALERT             14 /* RFC3429 */
 #define MPLS_LABEL_EXTENSION            15 /* RFC7274 */
 
+#define MPLS_LABEL_FIRST_UNRESERVED     16 /* RFC3032 */
+
 #endif /* _UAPI_MPLS_H */
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 88cfaa241c07..b6b9a6c4e784 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -293,7 +293,7 @@ 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 >= MPLS_LABEL_FIRST_UNRESERVED))
                 rtmsg_lfib(event, index, rt, nlh, net, portid, nlm_flags);
 }
 
@@ -327,7 +327,8 @@ 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 = MPLS_LABEL_FIRST_UNRESERVED; index < platform_labels;
+             index++) {
                 if (!rtnl_dereference(platform_label[index]))
                         return index;
         }
@@ -436,8 +437,8 @@ 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 < MPLS_LABEL_FIRST_UNRESERVED)
                 goto errout;
 
         /* The full 20 bit range may not be supported. */
@@ -516,8 +517,8 @@ 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 < MPLS_LABEL_FIRST_UNRESERVED)
                 goto errout;
 
         /* The full 20 bit range may not be supported */
@@ -835,8 +836,8 @@ 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 < MPLS_LABEL_FIRST_UNRESERVED)
                                 goto errout;
 
                         break;
@@ -961,8 +962,8 @@ 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 < MPLS_LABEL_FIRST_UNRESERVED)
+                index = MPLS_LABEL_FIRST_UNRESERVED;
 
         platform_label = rtnl_dereference(net->mpls.platform_label);
         platform_labels = net->mpls.platform_labels;