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ipv6: omit traffic class when calculating flow hash 

Some of the code paths calculating flow hash for IPv6 use flowlabel member
of struct flowi6 which, despite its name, encodes both flow label and
traffic class. If traffic class changes within a TCP connection (as e.g.
ssh does), ECMP route can switch between path. It's also inconsistent with
other code paths where ip6_flowlabel() (returning only flow label) is used
to feed the key.

Use only flow label everywhere, including one place where hash key is set
using ip6_flowinfo().

Fixes: 51ebd31815 ("ipv6: add support of equal cost multipath (ECMP)")
Fixes: f70ea018da ("net: Add functions to get skb->hash based on flow structures")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
zero-colors
Michal Kubecek 2018-06-04 11:36:05 +02:00 committed by David S. Miller
parent a925ab48da
commit fa1be7e01e
3 changed files with 8 additions and 3 deletions
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5
include/net/ipv6.h
View File

@ -907,6 +907,11 @@ static inline __be32 ip6_make_flowinfo(unsigned int tclass, __be32 flowlabel)
return htonl(tclass << IPV6_TCLASS_SHIFT) | flowlabel;
}
static inline __be32 flowi6_get_flowlabel(const struct flowi6 *fl6)
{
return fl6->flowlabel & IPV6_FLOWLABEL_MASK;
}
/*
* Prototypes exported by ipv6
*/

2
net/core/flow_dissector.c
View File

@ -1334,7 +1334,7 @@ __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys)
keys->ports.src = fl6->fl6_sport;
keys->ports.dst = fl6->fl6_dport;
keys->keyid.keyid = fl6->fl6_gre_key;
keys->tags.flow_label = (__force u32)fl6->flowlabel;
keys->tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6);
keys->basic.ip_proto = fl6->flowi6_proto;
return flow_hash_from_keys(keys);

4
net/ipv6/route.c
View File

@ -1981,7 +1981,7 @@ out:
} else {
keys->addrs.v6addrs.src = key_iph->saddr;
keys->addrs.v6addrs.dst = key_iph->daddr;
keys->tags.flow_label = ip6_flowinfo(key_iph);
keys->tags.flow_label = ip6_flowlabel(key_iph);
keys->basic.ip_proto = key_iph->nexthdr;
}
}
@ -2002,7 +2002,7 @@ u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
} 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.tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6);
hash_keys.basic.ip_proto = fl6->flowi6_proto;
}
break;