[IPV4]: Add LC-Trie FIB lookup algorithm.

Signed-off-by: Robert Olsson <Robert.Olsson@data.slu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/Kconfig

 #
 # 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

net/ipv4/Makefile

@@ -7,8 +7,10 @@ obj-y     := utils.o route.o inetpeer.o protocol.o \
 	     ip_output.o ip_sockglue.o \
 	     tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o tcp_minisocks.o \
 	     datagram.o raw.o udp.o arp.o icmp.o devinet.o af_inet.o igmp.o \
-	     sysctl_net_ipv4.o fib_frontend.o fib_semantics.o fib_hash.o
+	     sysctl_net_ipv4.o fib_frontend.o fib_semantics.o
 
+obj-$(CONFIG_IP_FIB_HASH) += fib_hash.o
+obj-$(CONFIG_IP_FIB_TRIE) += fib_trie.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_IP_MULTIPLE_TABLES) += fib_rules.o
 obj-$(CONFIG_IP_MROUTE) += ipmr.o

net/ipv4/af_inet.c

@@ -1119,6 +1119,10 @@ module_init(inet_init);
 #ifdef CONFIG_PROC_FS
 extern int  fib_proc_init(void);
 extern void fib_proc_exit(void);
+#ifdef CONFIG_IP_FIB_TRIE
+extern int  fib_stat_proc_init(void);
+extern void fib_stat_proc_exit(void);
+#endif
 extern int  ip_misc_proc_init(void);
 extern int  raw_proc_init(void);
 extern void raw_proc_exit(void);
@@ -1139,11 +1143,19 @@ static int __init ipv4_proc_init(void)
 		goto out_udp;
 	if (fib_proc_init())
 		goto out_fib;
+#ifdef CONFIG_IP_FIB_TRIE
+         if (fib_stat_proc_init())
+                 goto out_fib_stat;
+ #endif
 	if (ip_misc_proc_init())
 		goto out_misc;
 out:
 	return rc;
 out_misc:
+#ifdef CONFIG_IP_FIB_TRIE
+ 	fib_stat_proc_exit();
+out_fib_stat:
+#endif
 	fib_proc_exit();
 out_fib:
 	udp4_proc_exit();