[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>

1 files changed, 11 insertions, 1 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 3b56be85234e..966ab6b3022e 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1023,6 +1023,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
         int lifetime;
         struct ndisc_options ndopts;
         int optlen;
+        unsigned int pref = 0;
 
         __u8 * opt = (__u8 *)(ra_msg + 1);
 
@@ -1086,6 +1087,13 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 
         lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
 
+#ifdef CONFIG_IPV6_ROUTER_PREF
+        pref = ra_msg->icmph.icmp6_router_pref;
+        /* 10b is handled as if it were 00b (medium) */
+        if (pref == ICMPV6_ROUTER_PREF_INVALID)
+                pref = ICMPV6_ROUTER_PREF_MEDIUM;
+#endif
+
         rt = rt6_get_dflt_router(&skb->nh.ipv6h->saddr, skb->dev);
 
         if (rt)
@@ -1101,7 +1109,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
                 ND_PRINTK3(KERN_DEBUG
                            "ICMPv6 RA: adding default router.\n");
 
-                rt = rt6_add_dflt_router(&skb->nh.ipv6h->saddr, skb->dev);
+                rt = rt6_add_dflt_router(&skb->nh.ipv6h->saddr, skb->dev, pref);
                 if (rt == NULL) {
                         ND_PRINTK0(KERN_ERR
                                    "ICMPv6 RA: %s() failed to add default route.\n",
@@ -1120,6 +1128,8 @@ static void ndisc_router_discovery(struct sk_buff *skb)
                         return;
                 }
                 neigh->flags |= NTF_ROUTER;
+        } else if (rt) {
+                rt->rt6i_flags |= (rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
         }
 
         if (rt)