[IPV4]: Move FIB lookup algorithm choice under IP_ADVANCED_ROUTING

Most users need not be concerned with a complex choice of what
FIB lookup algorithm to use.  So give them the safe default of
IP_FIB_HASH if IP_ADVANCED_ROUTING is disabled.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 38 insertions, 26 deletions

diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 690e88ba2484..7bcfb84126d1 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -1,32 +1,6 @@
 #
 # IP configuration
 #
-choice 
-        prompt "Choose IP: FIB lookup"
-        depends on INET
-        default IP_FIB_HASH
-
-config IP_FIB_HASH
-        bool "FIB_HASH"
-        ---help---
-        Current FIB is very proven and good enough for most users.
-
-config IP_FIB_TRIE
-        bool "FIB_TRIE"
-        ---help---
-        Use new experimental LC-trie as FIB lookup algoritm. 
-        This improves lookup performance
-        
-        LC-trie is described in:
-        
-        IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
-        IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
-        An experimental study of compression methods for dynamic tries
-        Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
-        http://www.nada.kth.se/~snilsson/public/papers/dyntrie2/
-       
-endchoice
-
 config IP_MULTICAST
         bool "IP: multicasting"
         depends on INET
@@ -79,6 +53,44 @@ config IP_ADVANCED_ROUTER
 
           If unsure, say N here.
 
+choice 
+        prompt "Choose IP: FIB lookup algorithm (choose FIB_HASH if unsure)"
+        depends on IP_ADVANCED_ROUTER
+        default IP_FIB_HASH
+
+config IP_FIB_HASH
+        bool "FIB_HASH"
+        ---help---
+        Current FIB is very proven and good enough for most users.
+
+config IP_FIB_TRIE
+        bool "FIB_TRIE"
+        ---help---
+        Use new experimental LC-trie as FIB lookup algoritm. 
+        This improves lookup performance if you have a large
+        number of routes.
+
+        LC-trie is a longest matching prefix lookup algorithm which
+        performs better than FIB_HASH for large routing tables.
+        But, it consumes more memory and is more complex.
+        
+        LC-trie is described in:
+        
+        IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
+        IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
+        An experimental study of compression methods for dynamic tries
+        Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
+        http://www.nada.kth.se/~snilsson/public/papers/dyntrie2/
+       
+endchoice
+
+# If the user does not enable advanced routing, he gets the safe
+# default of the fib-hash algorithm.
+config IP_FIB_HASH
+        bool
+        depends on !IP_ADVANCED_ROUTER
+        default y
+
 config IP_MULTIPLE_TABLES
         bool "IP: policy routing"
         depends on IP_ADVANCED_ROUTER