[IPV6] MIP6: Loadable module support for MIPv6.

This patch makes MIPv6 loadable module named "mip6".

Here is a modprobe.conf(5) example to load it automatically
when user application uses XFRM state for MIPv6:

alias xfrm-type-10-43 mip6
alias xfrm-type-10-60 mip6

Some MIPv6 feature is not included by this modular, however,
it should not be affected to other features like either IPsec
or IPv6 with and without the patch.
We may discuss XFRM, MH (RAW socket) and ancillary data/sockopt
separately for future work.

Loadable features:
* MH receiving check (to send ICMP error back)
* RO header parsing and building (i.e. RH2 and HAO in DSTOPTS)
* XFRM policy/state database handling for RO

These are NOT covered as loadable:
* Home Address flags and its rule on source address selection
* XFRM sub policy (depends on its own kernel option)
* XFRM functions to receive RO as IPv6 extension header
* MH sending/receiving through raw socket if user application
  opens it (since raw socket allows to do so)
* RH2 sending as ancillary data
* RH2 operation with setsockopt(2)

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 10 insertions, 5 deletions

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index f3531d0bcd05..33b593e17441 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -61,7 +61,7 @@ extern int			addrconf_set_dstaddr(void __user *arg);
 extern int                      ipv6_chk_addr(struct in6_addr *addr,
                                               struct net_device *dev,
                                               int strict);
-#ifdef CONFIG_IPV6_MIP6
+#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 extern int                      ipv6_chk_home_addr(struct in6_addr *addr);
 #endif
 extern struct inet6_ifaddr *    ipv6_get_ifaddr(struct in6_addr *addr,
diff --git a/include/net/mip6.h b/include/net/mip6.h
index 68263c6d9996..63272610a24a 100644
--- a/include/net/mip6.h
+++ b/include/net/mip6.h
@@ -54,8 +54,4 @@ struct ip6_mh {
 #define IP6_MH_TYPE_BERROR      7   /* Binding Error */
 #define IP6_MH_TYPE_MAX         IP6_MH_TYPE_BERROR
 
-extern int mip6_init(void);
-extern void mip6_fini(void);
-extern int mip6_mh_filter(struct sock *sk, struct sk_buff *skb);
-
 #endif
diff --git a/include/net/rawv6.h b/include/net/rawv6.h
index af8960878ef4..a5819891d525 100644
--- a/include/net/rawv6.h
+++ b/include/net/rawv6.h
@@ -3,6 +3,8 @@
 
 #ifdef __KERNEL__
 
+#include <net/protocol.h>
+
 #define RAWV6_HTABLE_SIZE       MAX_INET_PROTOS
 extern struct hlist_head raw_v6_htable[RAWV6_HTABLE_SIZE];
 extern rwlock_t raw_v6_lock;
@@ -23,6 +25,13 @@ extern void			rawv6_err(struct sock *sk,
                                           int type, int code, 
                                           int offset, __be32 info);
 
+#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
+int rawv6_mh_filter_register(int (*filter)(struct sock *sock,
+                                           struct sk_buff *skb));
+int rawv6_mh_filter_unregister(int (*filter)(struct sock *sock,
+                                             struct sk_buff *skb));
+#endif
+
 #endif
 
 #endif