ipv6: omit traffic class when calculating flow hash

[ Upstream commit fa1be7e01ea863e911349e30456706749518eeab ]

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: 51ebd3181572 ("ipv6: add support of equal cost multipath (ECMP)")
Fixes: f70ea018da06 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 836f31af1369b9c6967073eed66ce5a062e4f9c2..a406f2e8680a214f3f5d236c998543d36b631f8e 100644 (file)
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -906,6 +906,11 @@ 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
  */

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index d29f09bc5ff90c457513c46200310cb00dd0c188..0234f8d1f0ac88644c7d524479e6a9f1b12bc9f9 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -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);

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f4d61736c41abe8cd7f439c4a37100e90c1eacca..4530a82aaa2ee53cb0e08ad70a14e473d2342dd2 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1868,7 +1868,7 @@ 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;
        }
 }
@@ -1889,7 +1889,7 @@ 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;