LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH net v2] ipv6: omit traffic class when calculating flow hash
@ 2018-06-02  7:40 Michal Kubecek
  2018-06-02  9:39 ` Ido Schimmel
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Michal Kubecek @ 2018-06-02  7:40 UTC (permalink / raw)
  To: David S. Miller
  Cc: netdev, linux-kernel, Nicolas Dichtel, Tom Herbert, David Ahern,
	Ido Schimmel

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 incosistent 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>
---
v2: introduce and use an inline helper as suggested by David Ahern

 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 836f31af1369..7fbdc3e9e25d 100644
--- 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 u32 flowi6_get_flowlabel(const struct flowi6 *fl6)
+{
+	return (__force u32)(fl6->flowlabel & IPV6_FLOWLABEL_MASK);
+}
+
 /*
  *	Prototypes exported by ipv6
  */
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index d29f09bc5ff9..64e5cb8c0b3e 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 = 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 f4d61736c41a..b208cd597510 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1868,7 +1868,7 @@ static void ip6_multipath_l3_keys(const struct sk_buff *skb,
 	} 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 = flowi6_get_flowlabel(fl6);
 			hash_keys.basic.ip_proto = fl6->flowi6_proto;
 		}
 		break;
-- 
2.17.1

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net v2] ipv6: omit traffic class when calculating flow hash
  2018-06-02  7:40 [PATCH net v2] ipv6: omit traffic class when calculating flow hash Michal Kubecek
@ 2018-06-02  9:39 ` Ido Schimmel
  2018-06-02 20:33 ` David Ahern
  2018-06-03 15:00 ` David Ahern
  2 siblings, 0 replies; 6+ messages in thread
From: Ido Schimmel @ 2018-06-02  9:39 UTC (permalink / raw)
  To: Michal Kubecek
  Cc: David S. Miller, netdev, linux-kernel, Nicolas Dichtel,
	Tom Herbert, David Ahern

On Sat, Jun 02, 2018 at 09:40:34AM +0200, Michal Kubecek wrote:
> 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 incosistent 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>

Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net v2] ipv6: omit traffic class when calculating flow hash
  2018-06-02  7:40 [PATCH net v2] ipv6: omit traffic class when calculating flow hash Michal Kubecek
  2018-06-02  9:39 ` Ido Schimmel
@ 2018-06-02 20:33 ` David Ahern
  2018-06-03 15:00 ` David Ahern
  2 siblings, 0 replies; 6+ messages in thread
From: David Ahern @ 2018-06-02 20:33 UTC (permalink / raw)
  To: Michal Kubecek, David S. Miller
  Cc: netdev, linux-kernel, Nicolas Dichtel, Tom Herbert, Ido Schimmel

On 6/2/18 1:40 AM, Michal Kubecek wrote:
> 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 incosistent 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>
> ---
> v2: introduce and use an inline helper as suggested by David Ahern
> 
>  include/net/ipv6.h        | 5 +++++
>  net/core/flow_dissector.c | 2 +-
>  net/ipv6/route.c          | 4 ++--
>  3 files changed, 8 insertions(+), 3 deletions(-)
> 

Acked-by: David Ahern <dsahern@gmail.com>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net v2] ipv6: omit traffic class when calculating flow hash
  2018-06-02  7:40 [PATCH net v2] ipv6: omit traffic class when calculating flow hash Michal Kubecek
  2018-06-02  9:39 ` Ido Schimmel
  2018-06-02 20:33 ` David Ahern
@ 2018-06-03 15:00 ` David Ahern
  2018-06-04  9:36   ` [PATCH net v3] " Michal Kubecek
  2 siblings, 1 reply; 6+ messages in thread
From: David Ahern @ 2018-06-03 15:00 UTC (permalink / raw)
  To: Michal Kubecek, David S. Miller
  Cc: netdev, linux-kernel, Nicolas Dichtel, Tom Herbert, Ido Schimmel

On 6/2/18 1:40 AM, Michal Kubecek wrote:
> diff --git a/include/net/ipv6.h b/include/net/ipv6.h
> index 836f31af1369..7fbdc3e9e25d 100644
> --- 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 u32 flowi6_get_flowlabel(const struct flowi6 *fl6)
> +{
> +	return (__force u32)(fl6->flowlabel & IPV6_FLOWLABEL_MASK);
> +}
> +
>  /*
>   *	Prototypes exported by ipv6
>   */

discussing the fix for net-next and making the label vs info consistent,
Michal notes a few places where this helper is needed as a __be32, so
the typecast should be outside of this helper.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH net v3] ipv6: omit traffic class when calculating flow hash
  2018-06-03 15:00 ` David Ahern
@ 2018-06-04  9:36   ` Michal Kubecek
  2018-06-04 17:22     ` David Miller
  0 siblings, 1 reply; 6+ messages in thread
From: Michal Kubecek @ 2018-06-04  9:36 UTC (permalink / raw)
  To: David S. Miller
  Cc: netdev, linux-kernel, Nicolas Dichtel, Tom Herbert, David Ahern,
	Ido Schimmel

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>
---
v2: introduce and use an inline helper as suggested by David Ahern
v3: keep the cast out of the helper to make future cleanup easier

 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 836f31af1369..a406f2e8680a 100644
--- 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 d29f09bc5ff9..0234f8d1f0ac 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 f4d61736c41a..4530a82aaa2e 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1868,7 +1868,7 @@ static void ip6_multipath_l3_keys(const struct sk_buff *skb,
 	} 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;
-- 
2.17.1

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net v3] ipv6: omit traffic class when calculating flow hash
  2018-06-04  9:36   ` [PATCH net v3] " Michal Kubecek
@ 2018-06-04 17:22     ` David Miller
  0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2018-06-04 17:22 UTC (permalink / raw)
  To: mkubecek; +Cc: netdev, linux-kernel, nicolas.dichtel, tom, dsahern, idosch

From: Michal Kubecek <mkubecek@suse.cz>
Date: Mon, 4 Jun 2018 11:36:05 +0200

> 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>
> ---
> v2: introduce and use an inline helper as suggested by David Ahern
> v3: keep the cast out of the helper to make future cleanup easier

Applied and queued up for -stable, thank you.

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2018-06-04 17:22 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-06-02  7:40 [PATCH net v2] ipv6: omit traffic class when calculating flow hash Michal Kubecek
2018-06-02  9:39 ` Ido Schimmel
2018-06-02 20:33 ` David Ahern
2018-06-03 15:00 ` David Ahern
2018-06-04  9:36   ` [PATCH net v3] " Michal Kubecek
2018-06-04 17:22     ` David Miller

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).