Hide kernel option ROUTETABLES evaluations in the implementation

rather than the header file.  With this also move RT_MAXFIBS and
RT_NUMFIBS into the implemantion to avoid further usage in other
code. rt_numfibs is all that should be needed.

This allows users to change the number of FIBs from 1..RT_MAXFIBS(16)
dynamically using the tunable without the need to change the kernel
config for the maximum anymore.  This means that thet multi-FIB
feature is now fully available with GENERIC kernels.
The kernel option ROUTETABLES can still be used to set the default
numbers of FIBs in absence of the tunable.

Ok.ed by:	julian, hrs, melifaro
MFC after:	2 weeks

2 files changed, 18 insertions, 21 deletions

diff --git a/sys/net/route.c b/sys/net/route.c
index c48a4ac..e69ce48 100644
--- a/sys/net/route.c
+++ b/sys/net/route.c
@@ -68,6 +68,24 @@
 
 #include <vm/uma.h>
 
+/* We use 4 bits in the mbuf flags, thus we are limited to 16 FIBS. */
+#define	RT_MAXFIBS	16
+
+/* Kernel config default option. */
+#ifdef ROUTETABLES
+#if ROUTETABLES <= 0
+#error "ROUTETABLES defined too low"
+#endif
+#if ROUTETABLES > RT_MAXFIBS
+#error "ROUTETABLES defined too big"
+#endif
+#define	RT_NUMFIBS	ROUTETABLES
+#endif /* ROUTETABLES */
+/* Initialize to default if not otherwise set. */
+#ifndef	RT_NUMFIBS
+#define	RT_NUMFIBS	1
+#endif
+
 u_int rt_numfibs = RT_NUMFIBS;
 SYSCTL_UINT(_net, OID_AUTO, fibs, CTLFLAG_RD, &rt_numfibs, 0, "");
 /*
diff --git a/sys/net/route.h b/sys/net/route.h
index a400deb..1de222a 100644
--- a/sys/net/route.h
+++ b/sys/net/route.h
@@ -90,27 +90,6 @@ struct rt_metrics {
 #define	RTM_RTTUNIT	1000000	/* units for rtt, rttvar, as units per sec */
 #define	RTTTOPRHZ(r)	((r) / (RTM_RTTUNIT / PR_SLOWHZ))
 
-/* MRT compile-time constants */
-#ifdef _KERNEL
- #ifndef ROUTETABLES
-  #define RT_NUMFIBS 1
-  #define RT_MAXFIBS 1
- #else
-  /* while we use 4 bits in the mbuf flags, we are limited to 16 */
-  #define RT_MAXFIBS 16
-  #if ROUTETABLES > RT_MAXFIBS
-   #define RT_NUMFIBS RT_MAXFIBS
-   #error "ROUTETABLES defined too big"
-  #else
-   #if ROUTETABLES == 0
-    #define RT_NUMFIBS 1
-   #else
-    #define RT_NUMFIBS ROUTETABLES
-   #endif
-  #endif
- #endif
-#endif
-
 #define	RT_DEFAULT_FIB	0	/* Explicitly mark fib=0 restricted cases */
 extern u_int rt_numfibs;	/* number fo usable routing tables */
 /*