| Message ID | 1347061251-2019-1-git-send-email-chema@google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, 2012-09-07 at 16:40 -0700, Chema Gonzalez wrote: > In the current rxhash calculation function, while the > sorting of the ports/addrs is coherent (you get the > same rxhash for packets sharing the same 4-tuple, in > both directions), ports and addrs are sorted > independently. This implies packets from a connection > between the same addresses but crossed ports hash to > the same rxhash. > > For example, traffic between A=S:l and B=L:s is hashed > (in both directions) from {L, S, {s, l}}. The same > rxhash is obtained for packets between C=S:s and D=L:l. > > This patch ensures that you either swap both addrs and ports, > or you swap none. Traffic between A and B, and traffic > between C and D, get their rxhash from different sources > ({L, S, {l, s}} for A<->B, and {L, S, {s, l}} for C<->D) > > The patch is co-written with Eric Dumazet <edumazet@google.com> > > Signed-off-by: Chema Gonzalez <chema@google.com> > --- Signed-off-by: Eric Dumazet <edumazet@google.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Sat, 08 Sep 2012 10:18:40 +0200 > On Fri, 2012-09-07 at 16:40 -0700, Chema Gonzalez wrote: >> In the current rxhash calculation function, while the >> sorting of the ports/addrs is coherent (you get the >> same rxhash for packets sharing the same 4-tuple, in >> both directions), ports and addrs are sorted >> independently. This implies packets from a connection >> between the same addresses but crossed ports hash to >> the same rxhash. >> >> For example, traffic between A=S:l and B=L:s is hashed >> (in both directions) from {L, S, {s, l}}. The same >> rxhash is obtained for packets between C=S:s and D=L:l. >> >> This patch ensures that you either swap both addrs and ports, >> or you swap none. Traffic between A and B, and traffic >> between C and D, get their rxhash from different sources >> ({L, S, {l, s}} for A<->B, and {L, S, {s, l}} for C<->D) >> >> The patch is co-written with Eric Dumazet <edumazet@google.com> >> >> Signed-off-by: Chema Gonzalez <chema@google.com> >> --- > > Signed-off-by: Eric Dumazet <edumazet@google.com> Applied and queued up for -stable, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/core/dev.c b/net/core/dev.c index b1e6d63..dcc673d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2655,15 +2655,16 @@ void __skb_get_rxhash(struct sk_buff *skb) if (!skb_flow_dissect(skb, &keys)) return; - if (keys.ports) { - if ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]) - swap(keys.port16[0], keys.port16[1]); + if (keys.ports) skb->l4_rxhash = 1; - } /* get a consistent hash (same value on both flow directions) */ - if ((__force u32)keys.dst < (__force u32)keys.src) + if (((__force u32)keys.dst < (__force u32)keys.src) || + (((__force u32)keys.dst == (__force u32)keys.src) && + ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) { swap(keys.dst, keys.src); + swap(keys.port16[0], keys.port16[1]); + } hash = jhash_3words((__force u32)keys.dst, (__force u32)keys.src,
In the current rxhash calculation function, while the sorting of the ports/addrs is coherent (you get the same rxhash for packets sharing the same 4-tuple, in both directions), ports and addrs are sorted independently. This implies packets from a connection between the same addresses but crossed ports hash to the same rxhash. For example, traffic between A=S:l and B=L:s is hashed (in both directions) from {L, S, {s, l}}. The same rxhash is obtained for packets between C=S:s and D=L:l. This patch ensures that you either swap both addrs and ports, or you swap none. Traffic between A and B, and traffic between C and D, get their rxhash from different sources ({L, S, {l, s}} for A<->B, and {L, S, {s, l}} for C<->D) The patch is co-written with Eric Dumazet <edumazet@google.com> Signed-off-by: Chema Gonzalez <chema@google.com> --- net/core/dev.c | 11 ++++++----- 1 files changed, 6 insertions(+), 5 deletions(-)