[IPV6]: Seperate sit driver to extra module

This patch removes the driver of the IPv6-in-IPv4 tunnel driver (sit)
from the IPv6 module. It adds an option to Kconfig which makes it
possible to compile it as a seperate module.
Signed-off-by: Joerg Roedel <joro-lkml@zlug.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/Kconfig

@@ -153,6 +153,19 @@ config INET6_XFRM_MODE_ROUTEOPTIMIZATION
 	---help---
 	  Support for MIPv6 route optimization mode.
 
+config IPV6_SIT
+	tristate "IPv6: IPv6-in-IPv4 tunnel (SIT driver)"
+	depends on IPV6
+	default y
+	---help---
+	  Tunneling means encapsulating data of one protocol type within
+	  another protocol and sending it over a channel that understands the
+	  encapsulating protocol. This driver implements encapsulation of IPv6
+	  into IPv4 packets. This is useful if you want to connect two IPv6
+	  networks over an IPv4-only path.
+
+	  Saying M here will produce a module called sit.ko. If unsure, say Y.
+
 config IPV6_TUNNEL
 	tristate "IPv6: IPv6-in-IPv6 tunnel"
 	select INET6_TUNNEL

net/ipv6/Makefile

@@ -4,7 +4,7 @@
 
 obj-$(CONFIG_IPV6) += ipv6.o
 
-ipv6-objs :=	af_inet6.o anycast.o ip6_output.o ip6_input.o addrconf.o sit.o \
+ipv6-objs :=	af_inet6.o anycast.o ip6_output.o ip6_input.o addrconf.o \
 		route.o ip6_fib.o ipv6_sockglue.o ndisc.o udp.o raw.o \
 		protocol.o icmp.o mcast.o reassembly.o tcp_ipv6.o \
 		exthdrs.o sysctl_net_ipv6.o datagram.o proc.o \
@@ -29,6 +29,7 @@ obj-$(CONFIG_INET6_XFRM_MODE_ROUTEOPTIMIZATION) += xfrm6_mode_ro.o
 obj-$(CONFIG_INET6_XFRM_MODE_BEET) += xfrm6_mode_beet.o
 obj-$(CONFIG_NETFILTER)	+= netfilter/
 
+obj-$(CONFIG_IPV6_SIT) += sit.o
 obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o
 
 obj-y += exthdrs_core.o

net/ipv6/af_inet6.c

@@ -850,7 +850,6 @@ static int __init inet6_init(void)
 	err = addrconf_init();
 	if (err)
 		goto addrconf_fail;
-	sit_init();
 
 	/* Init v6 extension headers. */
 	ipv6_rthdr_init();
@@ -927,7 +926,6 @@ static void __exit inet6_exit(void)
 	mip6_fini();
 #endif
 	/* Cleanup code parts. */
-	sit_cleanup();
 	ip6_flowlabel_cleanup();
 	addrconf_cleanup();
 	ip6_route_cleanup();

net/ipv6/sit.c

@@ -850,3 +850,6 @@ int __init sit_init(void)
 	inet_del_protocol(&sit_protocol, IPPROTO_IPV6);
 	goto out;
 }
+
+module_init(sit_init);
+module_exit(sit_cleanup);