mcast: define and use MRT[6]_MAX in ip[6]_mroute_opt()

This will ease further addition of new MRT[6]_* values and avoid to update
in6.h each time.
Note that we reduce the maximum value from 210 to 209, but 210 does not match
any known value in ip[6]_mroute_setsockopt().

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/mroute.h

@@ -9,7 +9,7 @@
 #ifdef CONFIG_IP_MROUTE
 static inline int ip_mroute_opt(int opt)
 {
-	return (opt >= MRT_BASE) && (opt <= MRT_BASE + 10);
+	return (opt >= MRT_BASE) && (opt <= MRT_MAX);
 }
 #else
 static inline int ip_mroute_opt(int opt)

include/linux/mroute6.h

@@ -10,7 +10,7 @@
 #ifdef CONFIG_IPV6_MROUTE
 static inline int ip6_mroute_opt(int opt)
 {
-	return (opt >= MRT6_BASE) && (opt <= MRT6_BASE + 10);
+	return (opt >= MRT6_BASE) && (opt <= MRT6_MAX);
 }
 #else
 static inline int ip6_mroute_opt(int opt)

include/uapi/linux/in6.h

@@ -259,17 +259,10 @@ struct in6_flowlabel_req {
 
 /*
  * Multicast Routing:
- * see include/linux/mroute6.h.
+ * see include/uapi/linux/mroute6.h.
  *
- * MRT6_INIT			200
- * MRT6_DONE			201
- * MRT6_ADD_MIF			202
- * MRT6_DEL_MIF			203
- * MRT6_ADD_MFC			204
- * MRT6_DEL_MFC			205
- * MRT6_VERSION			206
- * MRT6_ASSERT			207
- * MRT6_PIM			208
- * (reserved)			209
+ * MRT6_BASE			200
+ * ...
+ * MRT6_MAX
  */
 #endif /* _UAPI_LINUX_IN6_H */

include/uapi/linux/mroute.h

@@ -26,6 +26,7 @@
 #define MRT_ASSERT	(MRT_BASE+7)	/* Activate PIM assert mode		*/
 #define MRT_PIM		(MRT_BASE+8)	/* enable PIM code			*/
 #define MRT_TABLE	(MRT_BASE+9)	/* Specify mroute table ID		*/
+#define MRT_MAX		(MRT_BASE+9)
 
 #define SIOCGETVIFCNT	SIOCPROTOPRIVATE	/* IP protocol privates */
 #define SIOCGETSGCNT	(SIOCPROTOPRIVATE+1)

include/uapi/linux/mroute6.h

@@ -26,6 +26,7 @@
 #define MRT6_ASSERT	(MRT6_BASE+7)	/* Activate PIM assert mode		*/
 #define MRT6_PIM	(MRT6_BASE+8)	/* enable PIM code			*/
 #define MRT6_TABLE	(MRT6_BASE+9)	/* Specify mroute table ID		*/
+#define MRT6_MAX	(MRT6_BASE+9)
 
 #define SIOCGETMIFCNT_IN6	SIOCPROTOPRIVATE	/* IP protocol privates */
 #define SIOCGETSGCNT_IN6	(SIOCPROTOPRIVATE+1)