diff options
| author | Chema Gonzalez <chema@google.com> | 2012-09-07 13:40:50 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-13 05:38:44 +0900 |
| commit | 6b8fc5c4eba92b5cd3c9ca0d926e99831604f81e (patch) | |
| tree | ff3dafa60edf6c064aefc1003fa41863aa624f3b /net | |
| parent | e043257dde697ded17ed99f280cdb7643fdc007a (diff) | |
| download | lwn-6b8fc5c4eba92b5cd3c9ca0d926e99831604f81e.tar.gz lwn-6b8fc5c4eba92b5cd3c9ca0d926e99831604f81e.zip | |
net: small bug on rxhash calculation
[ Upstream commit 6862234238e84648c305526af2edd98badcad1e0 ]
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 3fd9cae3ccb1..f9ae3975f6b5 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2617,15 +2617,16 @@ 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, |