net/ipv6: Add support for path selection using hash of 5-tuple
Some operators prefer IPv6 path selection to use a standard 5-tuple
hash rather than just an L3 hash with the flow the label. To that end
add support to IPv6 for multipath hash policy similar to bf4e0a3db97eb
("net: ipv4: add support for ECMP hash policy choice"). The default
is still L3 which covers source and destination addresses along with
flow label and IPv6 protocol.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index d2b8368..f0ae584 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -450,7 +450,8 @@ static bool rt6_check_expired(const struct rt6_info *rt)
return false;
}
-static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
+static struct rt6_info *rt6_multipath_select(const struct net *net,
+ struct rt6_info *match,
struct flowi6 *fl6, int oif,
const struct sk_buff *skb,
int strict)
@@ -461,7 +462,7 @@ static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
* case it will always be non-zero. Otherwise now is the time to do it.
*/
if (!fl6->mp_hash)
- fl6->mp_hash = rt6_multipath_hash(fl6, skb, NULL);
+ fl6->mp_hash = rt6_multipath_hash(net, fl6, skb, NULL);
if (fl6->mp_hash <= atomic_read(&match->rt6i_nh_upper_bound))
return match;
@@ -932,7 +933,7 @@ static struct rt6_info *ip6_pol_route_lookup(struct net *net,
rt = rt6_device_match(net, rt, &fl6->saddr,
fl6->flowi6_oif, flags);
if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)
- rt = rt6_multipath_select(rt, fl6, fl6->flowi6_oif,
+ rt = rt6_multipath_select(net, rt, fl6, fl6->flowi6_oif,
skb, flags);
}
if (rt == net->ipv6.ip6_null_entry) {
@@ -1674,7 +1675,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
redo_rt6_select:
rt = rt6_select(net, fn, oif, strict);
if (rt->rt6i_nsiblings)
- rt = rt6_multipath_select(rt, fl6, oif, skb, strict);
+ rt = rt6_multipath_select(net, rt, fl6, oif, skb, strict);
if (rt == net->ipv6.ip6_null_entry) {
fn = fib6_backtrack(fn, &fl6->saddr);
if (fn)
@@ -1839,21 +1840,56 @@ static void ip6_multipath_l3_keys(const struct sk_buff *skb,
}
/* if skb is set it will be used and fl6 can be NULL */
-u32 rt6_multipath_hash(const struct flowi6 *fl6, const struct sk_buff *skb,
- struct flow_keys *flkeys)
+u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
+ const struct sk_buff *skb, struct flow_keys *flkeys)
{
struct flow_keys hash_keys;
u32 mhash;
- memset(&hash_keys, 0, sizeof(hash_keys));
- hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
- if (skb) {
- ip6_multipath_l3_keys(skb, &hash_keys, flkeys);
- } else {
- hash_keys.addrs.v6addrs.src = fl6->saddr;
- hash_keys.addrs.v6addrs.dst = fl6->daddr;
- hash_keys.tags.flow_label = (__force u32)fl6->flowlabel;
- hash_keys.basic.ip_proto = fl6->flowi6_proto;
+ switch (net->ipv6.sysctl.multipath_hash_policy) {
+ case 0:
+ memset(&hash_keys, 0, sizeof(hash_keys));
+ hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+ if (skb) {
+ ip6_multipath_l3_keys(skb, &hash_keys, flkeys);
+ } else {
+ hash_keys.addrs.v6addrs.src = fl6->saddr;
+ hash_keys.addrs.v6addrs.dst = fl6->daddr;
+ hash_keys.tags.flow_label = (__force u32)fl6->flowlabel;
+ hash_keys.basic.ip_proto = fl6->flowi6_proto;
+ }
+ break;
+ case 1:
+ if (skb) {
+ unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
+ struct flow_keys keys;
+
+ /* short-circuit if we already have L4 hash present */
+ if (skb->l4_hash)
+ return skb_get_hash_raw(skb) >> 1;
+
+ memset(&hash_keys, 0, sizeof(hash_keys));
+
+ if (!flkeys) {
+ skb_flow_dissect_flow_keys(skb, &keys, flag);
+ flkeys = &keys;
+ }
+ hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+ hash_keys.addrs.v6addrs.src = flkeys->addrs.v6addrs.src;
+ hash_keys.addrs.v6addrs.dst = flkeys->addrs.v6addrs.dst;
+ hash_keys.ports.src = flkeys->ports.src;
+ hash_keys.ports.dst = flkeys->ports.dst;
+ hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
+ } else {
+ memset(&hash_keys, 0, sizeof(hash_keys));
+ hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+ hash_keys.addrs.v6addrs.src = fl6->saddr;
+ hash_keys.addrs.v6addrs.dst = fl6->daddr;
+ hash_keys.ports.src = fl6->fl6_sport;
+ hash_keys.ports.dst = fl6->fl6_dport;
+ hash_keys.basic.ip_proto = fl6->flowi6_proto;
+ }
+ break;
}
mhash = flow_hash_from_keys(&hash_keys);
@@ -1884,7 +1920,7 @@ void ip6_route_input(struct sk_buff *skb)
flkeys = &_flkeys;
if (unlikely(fl6.flowi6_proto == IPPROTO_ICMPV6))
- fl6.mp_hash = rt6_multipath_hash(&fl6, skb, flkeys);
+ fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, flkeys);
skb_dst_drop(skb);
skb_dst_set(skb,
ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags));