[IPV6]: Add RFC4214 support

This patch includes support for the Intra-Site Automatic Tunnel
Addressing Protocol (ISATAP) per RFC4214. It uses the SIT
module, and is configured using extensions to the "iproute2"
utility. The diffs are specific to the Linux 2.6.24-rc2 kernel
distribution.

This version includes the diff for ./include/linux/if.h which was
missing in the v2.4 submission and is needed to make the
patch compile. The patch has been installed, compiled and
tested in a clean 2.6.24-rc2 kernel build area.

Signed-off-by: Fred L. Templin <fred.l.templin@boeing.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 31 insertions, 0 deletions

diff --git a/include/linux/if.h b/include/linux/if.h
index 186070d..5c9d1fa 100644
--- a/include/linux/if.h
+++ b/include/linux/if.h
@@ -63,6 +63,7 @@
 #define IFF_MASTER_ALB	0x10		/* bonding master, balance-alb.	*/
 #define IFF_BONDING	0x20		/* bonding master or slave	*/
 #define IFF_SLAVE_NEEDARP 0x40		/* need ARPs for validation	*/
+#define IFF_ISATAP	0x80		/* ISATAP interface (RFC4214)	*/
 
 #define IF_GET_IFACE	0x0001		/* for querying only */
 #define IF_GET_PROTO	0x0002
diff --git a/include/linux/if_tunnel.h b/include/linux/if_tunnel.h
index 660b501..228eb4e 100644
--- a/include/linux/if_tunnel.h
+++ b/include/linux/if_tunnel.h
@@ -17,6 +17,9 @@
 #define GRE_FLAGS	__constant_htons(0x00F8)
 #define GRE_VERSION	__constant_htons(0x0007)
 
+/* i_flags values for SIT mode */
+#define	SIT_ISATAP	0x0001
+
 struct ip_tunnel_parm
 {
 	char			name[IFNAMSIZ];
diff --git a/include/linux/in.h b/include/linux/in.h
index 3975cbf..a8f00ca 100644
--- a/include/linux/in.h
+++ b/include/linux/in.h
@@ -253,6 +253,14 @@ struct sockaddr_in {
 #define ZERONET(x)	(((x) & htonl(0xff000000)) == htonl(0x00000000))
 #define LOCAL_MCAST(x)	(((x) & htonl(0xFFFFFF00)) == htonl(0xE0000000))
 
+/* Special-Use IPv4 Addresses (RFC3330) */
+#define PRIVATE_10(x)	(((x) & htonl(0xff000000)) == htonl(0x0A000000))
+#define LINKLOCAL_169(x) (((x) & htonl(0xffff0000)) == htonl(0xA9FE0000))
+#define PRIVATE_172(x)	(((x) & htonl(0xfff00000)) == htonl(0xAC100000))
+#define TEST_192(x)	(((x) & htonl(0xffffff00)) == htonl(0xC0000200))
+#define ANYCAST_6TO4(x)	(((x) & htonl(0xffffff00)) == htonl(0xC0586300))
+#define PRIVATE_192(x)	(((x) & htonl(0xffff0000)) == htonl(0xC0A80000))
+#define TEST_198(x)	(((x) & htonl(0xfffe0000)) == htonl(0xC6120000))
 #endif
 
 #endif	/* _LINUX_IN_H */
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index bccc2fe..c56827d 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -17,6 +17,7 @@
 
 #define IPV6_MAX_ADDRESSES		16
 
+#include <linux/in.h>
 #include <linux/in6.h>
 
 struct prefix_info {
@@ -249,6 +250,24 @@ static inline int ipv6_addr_is_ll_all_routers(const struct in6_addr *addr)
 		addr->s6_addr32[3] == htonl(0x00000002));
 }
 
+static inline int ipv6_isatap_eui64(u8 *eui, __be32 addr)
+{
+	eui[0] = (ZERONET(addr) || PRIVATE_10(addr) || LOOPBACK(addr) ||
+		  LINKLOCAL_169(addr) || PRIVATE_172(addr) || TEST_192(addr) ||
+		  ANYCAST_6TO4(addr) || PRIVATE_192(addr) || TEST_198(addr) ||
+		  MULTICAST(addr) || BADCLASS(addr)) ? 0x00 : 0x02;
+	eui[1] = 0;
+	eui[2] = 0x5E;
+	eui[3] = 0xFE;
+	memcpy (eui+4, &addr, 4);
+	return 0;
+}
+
+static inline int ipv6_addr_is_isatap(const struct in6_addr *addr)
+{
+	return ((addr->s6_addr32[2] | htonl(0x02000000)) == htonl(0x02005EFE));
+}
+
 #ifdef CONFIG_PROC_FS
 extern int if6_proc_init(void);
 extern void if6_proc_exit(void);