[IPV6] SIT: Add PRL management for ISATAP.

This patch updates the Linux the Intra-Site Automatic Tunnel Addressing
Protocol (ISATAP) implementation. It places the ISATAP potential router
list (PRL) in the kernel and adds three new private ioctls for PRL
management.

[Add several changes of structure name, constant names etc. - yoshfuji]

Signed-off-by: Fred L. Templin <fred.l.templin@boeing.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ff72145d..e10e55c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -313,7 +313,8 @@
 	__u16			tc_verd;	/* traffic control verdict */
 #endif
 #endif
-	/* 2 byte hole */
+	__u8			ndisc_nodetype:2;
+	/* 14 bit hole */
 
 #ifdef CONFIG_NET_DMA
 	dma_cookie_t		dma_cookie;