Commit fa1be7e0 authored by Michal Kubecek's avatar Michal Kubecek Committed by David S. Miller
Browse files

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: 51ebd318 ("ipv6: add support of equal cost multipath (ECMP)")
Fixes: f70ea018 ("net: Add functions to get skb->hash based on flow structures")
Signed-off-by: default avatarMichal Kubecek <mkubecek@suse.cz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a925ab48

include/net/ipv6.h

+5 −0
Original line number Diff line number Diff line
@@ -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

 */

net/core/flow_dissector.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

net/ipv6/route.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

CRA Git | Maintained and supported by SUSTech CRA and CCSE