diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index ddf53dd1e9484db9a75e02b30cacf9fc47c7a04f..34ec321d6a03baaf1efdfe591a5ca1f27b1d276c 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -149,6 +149,7 @@ struct rt6_info {
*/
struct list_head rt6i_siblings;
unsigned int rt6i_nsiblings;
+ atomic_t rt6i_nh_upper_bound;
atomic_t rt6i_ref;
@@ -170,6 +171,7 @@ struct rt6_info {
u32 rt6i_metric;
u32 rt6i_pmtu;
/* more non-fragment space at head required */
+ int rt6i_nh_weight;
unsigned short rt6i_nfheader_len;
u8 rt6i_protocol;
u8 exception_bucket_flushed:1,
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 34cd3b0c6dedd6e54799f30a1f551b7a13fd7bbb..27d23a65f3cd0be2255859614690151e2d01b352 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -66,6 +66,12 @@ static inline bool rt6_need_strict(const struct in6_addr *daddr)
(IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);
}
+static inline bool rt6_qualify_for_ecmp(const struct rt6_info *rt)
+{
+ return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
+ RTF_GATEWAY;
+}
+
void ip6_route_input(struct sk_buff *skb);
struct dst_entry *ip6_route_input_lookup(struct net *net,
struct net_device *dev,
@@ -171,6 +177,7 @@ void rt6_clean_tohost(struct net *net, struct in6_addr *gateway);
void rt6_sync_up(struct net_device *dev, unsigned int nh_flags);
void rt6_disable_ip(struct net_device *dev, unsigned long event);
void rt6_sync_down_dev(struct net_device *dev, unsigned long event);
+void rt6_multipath_rebalance(struct rt6_info *rt);
static inline const struct rt6_info *skb_rt6_info(const struct sk_buff *skb)
{
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index b5f19703fca64892883389fc97c92116b9ed4b10..e31118f417b401a3ff01996f73c4aba325289fe9 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -796,12 +796,6 @@ insert_above:
return ln;
}
-static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
-{
- return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
- RTF_GATEWAY;
-}
-
static void fib6_copy_metrics(u32 *mp, const struct mx6_config *mxc)
{
int i;
@@ -991,6 +985,7 @@ next_iter:
rt6i_nsiblings++;
}
BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
+ rt6_multipath_rebalance(temp_sibling);
}
/*
@@ -1672,6 +1667,7 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
sibling->rt6i_nsiblings--;
rt->rt6i_nsiblings = 0;
list_del_init(&rt->rt6i_siblings);
+ rt6_multipath_rebalance(next_sibling);
}
/* Adjust walkers */
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 1054b059747f9e2f9f60202bd4937f088e745c15..1076ae0ea9d57594bdac8a871570c53efb2afbdb 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -455,7 +455,6 @@ static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
int strict)
{
struct rt6_info *sibling, *next_sibling;
- int route_choosen;
/* We might have already computed the hash for ICMPv6 errors. In such
* case it will always be non-zero. Otherwise now is the time to do it.
@@ -463,28 +462,19 @@ static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
if (!fl6->mp_hash)
fl6->mp_hash = rt6_multipath_hash(fl6, NULL);
- route_choosen = fl6->mp_hash % (match->rt6i_nsiblings + 1);
- /* Don't change the route, if route_choosen == 0
- * (siblings does not include ourself)
- */
- if (route_choosen)
- list_for_each_entry_safe(sibling, next_sibling,
- &match->rt6i_siblings, rt6i_siblings) {
- route_choosen--;
- if (route_choosen == 0) {
- struct inet6_dev *idev = sibling->rt6i_idev;
-
- if (sibling->rt6i_nh_flags & RTNH_F_DEAD)
- break;
- if (sibling->rt6i_nh_flags & RTNH_F_LINKDOWN &&
- idev->cnf.ignore_routes_with_linkdown)
- break;
- if (rt6_score_route(sibling, oif, strict) < 0)
- break;
- match = sibling;
- break;
- }
- }
+ if (fl6->mp_hash <= atomic_read(&match->rt6i_nh_upper_bound))
+ return match;
+
+ list_for_each_entry_safe(sibling, next_sibling, &match->rt6i_siblings,
+ rt6i_siblings) {
+ if (fl6->mp_hash > atomic_read(&sibling->rt6i_nh_upper_bound))
+ continue;
+ if (rt6_score_route(sibling, oif, strict) < 0)
+ break;
+ match = sibling;
+ break;
+ }
+
return match;
}
@@ -1833,10 +1823,10 @@ u32 rt6_multipath_hash(const struct flowi6 *fl6, const struct sk_buff *skb)
if (skb) {
ip6_multipath_l3_keys(skb, &hash_keys);
- return flow_hash_from_keys(&hash_keys);
+ return flow_hash_from_keys(&hash_keys) >> 1;
}
- return get_hash_from_flowi6(fl6);
+ return get_hash_from_flowi6(fl6) >> 1;
}
void ip6_route_input(struct sk_buff *skb)
@@ -2604,6 +2594,7 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
#endif
rt->rt6i_metric = cfg->fc_metric;
+ rt->rt6i_nh_weight = 1;
/* We cannot add true routes via loopback here,
they would result in kernel looping; promote them to reject routes
@@ -3481,6 +3472,99 @@ struct arg_netdev_event {
};
};
+static struct rt6_info *rt6_multipath_first_sibling(const struct rt6_info *rt)
+{
+ struct rt6_info *iter;
+ struct fib6_node *fn;
+
+ fn = rcu_dereference_protected(rt->rt6i_node,
+ lockdep_is_held(&rt->rt6i_table->tb6_lock));
+ iter = rcu_dereference_protected(fn->leaf,
+ lockdep_is_held(&rt->rt6i_table->tb6_lock));
+ while (iter) {
+ if (iter->rt6i_metric == rt->rt6i_metric &&
+ rt6_qualify_for_ecmp(iter))
+ return iter;
+ iter = rcu_dereference_protected(iter->rt6_next,
+ lockdep_is_held(&rt->rt6i_table->tb6_lock));
+ }
+
+ return NULL;
+}
+
+static bool rt6_is_dead(const struct rt6_info *rt)
+{
+ if (rt->rt6i_nh_flags & RTNH_F_DEAD ||
+ (rt->rt6i_nh_flags & RTNH_F_LINKDOWN &&
+ rt->rt6i_idev->cnf.ignore_routes_with_linkdown))
+ return true;
+
+ return false;
+}
+
+static int rt6_multipath_total_weight(const struct rt6_info *rt)
+{
+ struct rt6_info *iter;
+ int total = 0;
+
+ if (!rt6_is_dead(rt))
+ total += rt->rt6i_nh_weight;
+
+ list_for_each_entry(iter, &rt->rt6i_siblings, rt6i_siblings) {
+ if (!rt6_is_dead(iter))
+ total += iter->rt6i_nh_weight;
+ }
+
+ return total;
+}
+
+static void rt6_upper_bound_set(struct rt6_info *rt, int *weight, int total)
+{
+ int upper_bound = -1;
+
+ if (!rt6_is_dead(rt)) {
+ *weight += rt->rt6i_nh_weight;
+ upper_bound = DIV_ROUND_CLOSEST_ULL((u64) (*weight) << 31,
+ total) - 1;
+ }
+ atomic_set(&rt->rt6i_nh_upper_bound, upper_bound);
+}
+
+static void rt6_multipath_upper_bound_set(struct rt6_info *rt, int total)
+{
+ struct rt6_info *iter;
+ int weight = 0;
+
+ rt6_upper_bound_set(rt, &weight, total);
+
+ list_for_each_entry(iter, &rt->rt6i_siblings, rt6i_siblings)
+ rt6_upper_bound_set(iter, &weight, total);
+}
+
+void rt6_multipath_rebalance(struct rt6_info *rt)
+{
+ struct rt6_info *first;
+ int total;
+
+ /* In case the entire multipath route was marked for flushing,
+ * then there is no need to rebalance upon the removal of every
+ * sibling route.
+ */
+ if (!rt->rt6i_nsiblings || rt->should_flush)
+ return;
+
+ /* During lookup routes are evaluated in order, so we need to
+ * make sure upper bounds are assigned from the first sibling
+ * onwards.
+ */
+ first = rt6_multipath_first_sibling(rt);
+ if (WARN_ON_ONCE(!first))
+ return;
+
+ total = rt6_multipath_total_weight(first);
+ rt6_multipath_upper_bound_set(first, total);
+}
+
static int fib6_ifup(struct rt6_info *rt, void *p_arg)
{
const struct arg_netdev_event *arg = p_arg;
@@ -3489,6 +3573,7 @@ static int fib6_ifup(struct rt6_info *rt, void *p_arg)
if (rt != net->ipv6.ip6_null_entry && rt->dst.dev == arg->dev) {
rt->rt6i_nh_flags &= ~arg->nh_flags;
fib6_update_sernum_upto_root(dev_net(rt->dst.dev), rt);
+ rt6_multipath_rebalance(rt);
}
return 0;
@@ -3588,6 +3673,7 @@ static int fib6_ifdown(struct rt6_info *rt, void *p_arg)
rt6_multipath_nh_flags_set(rt, dev, RTNH_F_DEAD |
RTNH_F_LINKDOWN);
fib6_update_sernum(rt);
+ rt6_multipath_rebalance(rt);
}
return -2;
case NETDEV_CHANGE:
@@ -3595,6 +3681,7 @@ static int fib6_ifdown(struct rt6_info *rt, void *p_arg)
rt->rt6i_flags & (RTF_LOCAL | RTF_ANYCAST))
break;
rt->rt6i_nh_flags |= RTNH_F_LINKDOWN;
+ rt6_multipath_rebalance(rt);
break;
}
@@ -3938,6 +4025,8 @@ static int ip6_route_multipath_add(struct fib6_config *cfg,
goto cleanup;
}
+ rt->rt6i_nh_weight = rtnh->rtnh_hops + 1;
+
err = ip6_route_info_append(&rt6_nh_list, rt, &r_cfg);
if (err) {
dst_release_immediate(&rt->dst);
@@ -4160,7 +4249,7 @@ static int rt6_add_nexthop(struct sk_buff *skb, struct rt6_info *rt)
if (!rtnh)
goto nla_put_failure;
- rtnh->rtnh_hops = 0;
+ rtnh->rtnh_hops = rt->rt6i_nh_weight - 1;
rtnh->rtnh_ifindex = rt->dst.dev ? rt->dst.dev->ifindex : 0;
if (rt6_nexthop_info(skb, rt, &flags, true) < 0)