[IPV6]: ROUTE: Add support for Router Preference (RFC4191).

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 19 insertions, 3 deletions

diff --git a/include/linux/icmpv6.h b/include/linux/icmpv6.h
index 0cf6c8b12caf..c771a7db9871 100644
--- a/include/linux/icmpv6.h
+++ b/include/linux/icmpv6.h
@@ -40,14 +40,16 @@ struct icmp6hdr {
                 struct icmpv6_nd_ra {
                         __u8            hop_limit;
 #if defined(__LITTLE_ENDIAN_BITFIELD)
-                        __u8            reserved:6,
+                        __u8            reserved:4,
+                                        router_pref:2,
                                         other:1,
                                         managed:1;
 
 #elif defined(__BIG_ENDIAN_BITFIELD)
                         __u8            managed:1,
                                         other:1,
-                                        reserved:6;
+                                        router_pref:2,
+                                        reserved:4;
 #else
 #error  "Please fix <asm/byteorder.h>"
 #endif
@@ -70,8 +72,13 @@ struct icmp6hdr {
 #define icmp6_addrconf_managed  icmp6_dataun.u_nd_ra.managed
 #define icmp6_addrconf_other    icmp6_dataun.u_nd_ra.other
 #define icmp6_rt_lifetime       icmp6_dataun.u_nd_ra.rt_lifetime
+#define icmp6_router_pref       icmp6_dataun.u_nd_ra.router_pref
 };
 
+#define ICMPV6_ROUTER_PREF_LOW          0x3
+#define ICMPV6_ROUTER_PREF_MEDIUM       0x0
+#define ICMPV6_ROUTER_PREF_HIGH         0x1
+#define ICMPV6_ROUTER_PREF_INVALID      0x2
 
 #define ICMPV6_DEST_UNREACH             1
 #define ICMPV6_PKT_TOOBIG               2
diff --git a/include/linux/ipv6_route.h b/include/linux/ipv6_route.h
index d7c41d1d706a..f4b085c91608 100644
--- a/include/linux/ipv6_route.h
+++ b/include/linux/ipv6_route.h
@@ -27,8 +27,16 @@
 #define RTF_FLOW        0x02000000      /* flow significant route       */
 #define RTF_POLICY      0x04000000      /* policy route                 */
 
+#define RTF_PREF(pref)  ((pref) << 27)
+#define RTF_PREF_MASK   0x18000000
+
 #define RTF_LOCAL       0x80000000
 
+#ifdef __KERNEL__
+#define IPV6_EXTRACT_PREF(flag) (((flag) & RTF_PREF_MASK) >> 27)
+#define IPV6_DECODE_PREF(pref)  ((pref) ^ 2)    /* 1:low,2:med,3:high */
+#endif
+
 struct in6_rtmsg {
         struct in6_addr         rtmsg_dst;
         struct in6_addr         rtmsg_src;
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 01acca06d6dd..50161322b828 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -87,7 +87,8 @@ extern struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
 extern struct rt6_info *        rt6_get_dflt_router(struct in6_addr *addr,
                                                     struct net_device *dev);
 extern struct rt6_info *        rt6_add_dflt_router(struct in6_addr *gwaddr,
-                                                    struct net_device *dev);
+                                                    struct net_device *dev,
+                                                    unsigned int pref);
 
 extern void                     rt6_purge_dflt_routers(void);