Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933854Ab2JKC0U (ORCPT ); Wed, 10 Oct 2012 22:26:20 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:45929 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933397Ab2JKCMq (ORCPT ); Wed, 10 Oct 2012 22:12:46 -0400 X-Sasl-enc: 0imZhhBJHB3bBzZqkuTfgHD32QKZ/BmZdVPrvqQUmpxI 1349921565 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Chema Gonzalez , Eric Dumazet , "David S. Miller" Subject: [ 31/84] net: small bug on rxhash calculation Date: Thu, 11 Oct 2012 11:03:15 +0900 Message-Id: <20121011015422.685723751@linuxfoundation.org> X-Mailer: git-send-email 1.8.0.rc0.18.gf84667d In-Reply-To: <20121011015417.017144658@linuxfoundation.org> References: <20121011015417.017144658@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2265 Lines: 68 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chema Gonzalez [ 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 Signed-off-by: Chema Gonzalez Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/dev.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2559,16 +2559,17 @@ __u32 __skb_get_rxhash(struct sk_buff *s 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) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/