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 05:28:07 +0900 |
| commit | 74665a9b4fca3420c07f1e583242a477b2eb34b0 (patch) | |
| tree | 7c172d27a87fa9f24721810c0d03bfa79574f70d /net | |
| parent | 0ddaf88b27c6c942d3e921a2b0a7d8cae6d5be19 (diff) | |
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 d8bc889b50c..df6ee2884e7 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2559,16 +2559,17 @@ __u32 __skb_get_rxhash(struct sk_buff *skb) poff = proto_ports_offset(ip_proto); if (poff >= 0) { nhoff += ihl * 4 + poff; - if (pskb_may_pull(skb, nhoff + 4)) { + if (pskb_may_pull(skb, nhoff + 4)) ports.v32 = * (__force u32 *) (skb->data + nhoff); - if (ports.v16[1] < ports.v16[0]) - swap(ports.v16[0], ports.v16[1]); - } } /* get a consistent hash (same value on both flow directions) */ - if (addr2 < addr1) + if (addr2 < addr1 || + (addr2 == addr1 && + ports.v16[1] < ports.v16[0])) { swap(addr1, addr2); + swap(ports.v16[0], ports.v16[1]); + } hash = jhash_3words(addr1, addr2, ports.v32, hashrnd); if (!hash) |