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 bf4e0a3db9
("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>
This commit is contained in:

committed by
David S. Miller

parent
b75cc8f90f
commit
b4bac172e9
@@ -450,7 +450,8 @@ static bool rt6_check_expired(const struct rt6_info *rt)
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return false;
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}
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static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
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static struct rt6_info *rt6_multipath_select(const struct net *net,
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struct rt6_info *match,
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struct flowi6 *fl6, int oif,
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const struct sk_buff *skb,
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int strict)
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@@ -461,7 +462,7 @@ static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
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* case it will always be non-zero. Otherwise now is the time to do it.
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*/
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if (!fl6->mp_hash)
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fl6->mp_hash = rt6_multipath_hash(fl6, skb, NULL);
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fl6->mp_hash = rt6_multipath_hash(net, fl6, skb, NULL);
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if (fl6->mp_hash <= atomic_read(&match->rt6i_nh_upper_bound))
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return match;
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@@ -932,7 +933,7 @@ restart:
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rt = rt6_device_match(net, rt, &fl6->saddr,
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fl6->flowi6_oif, flags);
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if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)
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rt = rt6_multipath_select(rt, fl6, fl6->flowi6_oif,
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rt = rt6_multipath_select(net, rt, fl6, fl6->flowi6_oif,
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skb, flags);
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}
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if (rt == net->ipv6.ip6_null_entry) {
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@@ -1674,7 +1675,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
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redo_rt6_select:
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rt = rt6_select(net, fn, oif, strict);
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if (rt->rt6i_nsiblings)
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rt = rt6_multipath_select(rt, fl6, oif, skb, strict);
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rt = rt6_multipath_select(net, rt, fl6, oif, skb, strict);
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if (rt == net->ipv6.ip6_null_entry) {
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fn = fib6_backtrack(fn, &fl6->saddr);
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if (fn)
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@@ -1839,21 +1840,56 @@ out:
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}
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/* if skb is set it will be used and fl6 can be NULL */
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u32 rt6_multipath_hash(const struct flowi6 *fl6, const struct sk_buff *skb,
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struct flow_keys *flkeys)
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u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
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const struct sk_buff *skb, struct flow_keys *flkeys)
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{
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struct flow_keys hash_keys;
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u32 mhash;
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memset(&hash_keys, 0, sizeof(hash_keys));
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hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
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if (skb) {
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ip6_multipath_l3_keys(skb, &hash_keys, flkeys);
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} else {
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hash_keys.addrs.v6addrs.src = fl6->saddr;
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hash_keys.addrs.v6addrs.dst = fl6->daddr;
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hash_keys.tags.flow_label = (__force u32)fl6->flowlabel;
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hash_keys.basic.ip_proto = fl6->flowi6_proto;
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switch (net->ipv6.sysctl.multipath_hash_policy) {
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case 0:
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memset(&hash_keys, 0, sizeof(hash_keys));
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hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
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if (skb) {
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ip6_multipath_l3_keys(skb, &hash_keys, flkeys);
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} else {
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hash_keys.addrs.v6addrs.src = fl6->saddr;
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hash_keys.addrs.v6addrs.dst = fl6->daddr;
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hash_keys.tags.flow_label = (__force u32)fl6->flowlabel;
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hash_keys.basic.ip_proto = fl6->flowi6_proto;
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}
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break;
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case 1:
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if (skb) {
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unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
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struct flow_keys keys;
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/* short-circuit if we already have L4 hash present */
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if (skb->l4_hash)
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return skb_get_hash_raw(skb) >> 1;
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memset(&hash_keys, 0, sizeof(hash_keys));
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if (!flkeys) {
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skb_flow_dissect_flow_keys(skb, &keys, flag);
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flkeys = &keys;
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}
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hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
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hash_keys.addrs.v6addrs.src = flkeys->addrs.v6addrs.src;
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hash_keys.addrs.v6addrs.dst = flkeys->addrs.v6addrs.dst;
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hash_keys.ports.src = flkeys->ports.src;
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hash_keys.ports.dst = flkeys->ports.dst;
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hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
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} else {
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memset(&hash_keys, 0, sizeof(hash_keys));
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hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
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hash_keys.addrs.v6addrs.src = fl6->saddr;
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hash_keys.addrs.v6addrs.dst = fl6->daddr;
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hash_keys.ports.src = fl6->fl6_sport;
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hash_keys.ports.dst = fl6->fl6_dport;
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hash_keys.basic.ip_proto = fl6->flowi6_proto;
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}
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break;
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}
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mhash = flow_hash_from_keys(&hash_keys);
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@@ -1884,7 +1920,7 @@ void ip6_route_input(struct sk_buff *skb)
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flkeys = &_flkeys;
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if (unlikely(fl6.flowi6_proto == IPPROTO_ICMPV6))
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fl6.mp_hash = rt6_multipath_hash(&fl6, skb, flkeys);
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fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, flkeys);
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skb_dst_drop(skb);
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skb_dst_set(skb,
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ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags));
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