[PFKEYV2]: Extension for dynamic update of endpoint address(es)

Extend PF_KEYv2 framework so that user application can take advantage
of MIGRATE feature via PF_KEYv2 interface. User application can either
send or receive an MIGRATE message to/from PF_KEY socket.

Detail information can be found in the internet-draft
<draft-sugimoto-mip6-pfkey-migrate>.
Signed-off-by: Shinta Sugimoto <shinta.sugimoto@ericsson.com>
Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/pfkeyv2.h

@@ -251,7 +251,8 @@ struct sadb_x_sec_ctx {
 #define SADB_X_SPDEXPIRE	21
 #define SADB_X_SPDDELETE2	22
 #define SADB_X_NAT_T_NEW_MAPPING	23
-#define SADB_MAX		23
+#define SADB_X_MIGRATE		24
+#define SADB_MAX		24
 
 /* Security Association flags */
 #define SADB_SAFLAGS_PFS	1