4.16-stable review patch. If anyone has any objections, please let me know.
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From: Michal Kubecek mkubecek@suse.cz
[ 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 --- include/net/ipv6.h | 5 +++++ net/core/flow_dissector.c | 2 +- net/ipv6/route.c | 2 +- 3 files changed, 7 insertions(+), 2 deletions(-)
--- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -918,6 +918,11 @@ static inline __be32 ip6_make_flowinfo(u 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 */ --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1334,7 +1334,7 @@ __u32 __get_hash_from_flowi6(const struc 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); --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1850,7 +1850,7 @@ out: keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 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; }