fib_rules: fix suppressor names and default values

This change brings the suppressor attribute names into line; it also changes
the data types to provide a more consistent interface.

While -1 indicates that the suppressor is not enabled, values >= 0 for
suppress_prefixlen or suppress_ifgroup  reject routing decisions violating the
constraint.

This changes the previously presented behaviour of suppress_prefixlen, where a
prefix length _less_ than the attribute value was rejected. After this change,
a prefix length less than *or* equal to the value is considered a violation of
the rule constraint.

It also changes the default values for default and newly added rules (disabling
any suppression for those).

Signed-off-by: Stefan Tomanek <stefan.tomanek@wertarbyte.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index b78fd28..523be38 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -109,7 +109,7 @@
 	/* do not accept result if the route does
 	 * not meet the required prefix length
 	 */
-	if (result->prefixlen < rule->table_prefixlen_min)
+	if (result->prefixlen <= rule->suppress_prefixlen)
 		goto suppress_route;
 
 	/* do not accept result if the route uses a device