From fa1be7e01ea863e911349e30456706749518eeab Mon Sep 17 00:00:00 2001 From: Michal Kubecek Date: Mon, 4 Jun 2018 11:36:05 +0200 Subject: [PATCH] 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: 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 Signed-off-by: David S. Miller --- include/net/ipv6.h | 5 +++++ net/core/flow_dissector.c | 2 +- net/ipv6/route.c | 4 ++-- 3 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 798558fd1681..16475c269749 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -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 */ diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 4fc1e84d77ec..53f96e4f7bf5 100644 --- 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 22c4de2317d0..ce6696acba73 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -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;