[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>
diff --git a/include/linux/icmpv6.h b/include/linux/icmpv6.h
index 0cf6c8b..c771a7d 100644
--- a/include/linux/icmpv6.h
+++ b/include/linux/icmpv6.h
@@ -40,14 +40,16 @@
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 @@
#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 d7c41d1..f4b085c 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 01acca0..5016132 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -87,7 +87,8 @@
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);
diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index f925f20..c456ead 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -38,6 +38,17 @@
See <file:Documentation/networking/ip-sysctl.txt> for details.
+config IPV6_ROUTER_PREF
+ bool "IPv6: Router Preference (RFC 4191) support"
+ depends on IPV6
+ ---help---
+ Router Preference is an optional extension to the Router
+ Advertisement message to improve the ability of hosts
+ to pick more appropriate router, especially when the hosts
+ is placed in a multi-homed network.
+
+ If unsure, say N.
+
config INET6_AH
tristate "IPv6: AH transformation"
depends on IPV6
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 3b56be8..966ab6b 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1023,6 +1023,7 @@
int lifetime;
struct ndisc_options ndopts;
int optlen;
+ unsigned int pref = 0;
__u8 * opt = (__u8 *)(ra_msg + 1);
@@ -1086,6 +1087,13 @@
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 @@
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 @@
return;
}
neigh->flags |= NTF_ROUTER;
+ } else if (rt) {
+ rt->rt6i_flags |= (rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
}
if (rt)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 6a068e7..a7030fe 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -251,8 +251,11 @@
int m = rt6_check_dev(rt, oif);
if (!m && (strict & RT6_SELECT_F_IFACE))
return -1;
+#ifdef CONFIG_IPV6_ROUTER_PREF
+ m |= IPV6_DECODE_PREF(IPV6_EXTRACT_PREF(rt->rt6i_flags)) << 2;
+#endif
if (rt6_check_neigh(rt))
- m |= 4;
+ m |= 16;
else if (strict & RT6_SELECT_F_REACHABLE)
return -1;
return m;
@@ -1256,7 +1259,8 @@
}
struct rt6_info *rt6_add_dflt_router(struct in6_addr *gwaddr,
- struct net_device *dev)
+ struct net_device *dev,
+ unsigned int pref)
{
struct in6_rtmsg rtmsg;
@@ -1264,7 +1268,8 @@
rtmsg.rtmsg_type = RTMSG_NEWROUTE;
ipv6_addr_copy(&rtmsg.rtmsg_gateway, gwaddr);
rtmsg.rtmsg_metric = 1024;
- rtmsg.rtmsg_flags = RTF_GATEWAY | RTF_ADDRCONF | RTF_DEFAULT | RTF_UP | RTF_EXPIRES;
+ rtmsg.rtmsg_flags = RTF_GATEWAY | RTF_ADDRCONF | RTF_DEFAULT | RTF_UP | RTF_EXPIRES |
+ RTF_PREF(pref);
rtmsg.rtmsg_ifindex = dev->ifindex;