From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: [PATCH] veth: Fix the byte counters Date: Mon, 21 Mar 2011 14:40:29 -0700 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: , =?utf-8?Q?Micha=C5=82_Miros=C5=82aw?= , Eric Dumazet , Arnd Bergmann , Ben Greear , Patrick McHardy , Daniel Lezcano , Pavel Emelyanov To: David Miller Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:54873 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754108Ab1CUVkg (ORCPT ); Mon, 21 Mar 2011 17:40:36 -0400 Sender: netdev-owner@vger.kernel.org List-ID: Commit 44540960 "veth: move loopback logic to common location" introduced a bug in the packet counters. I don't understand why that happened as it is not explained in the comments and the mut check in dev_forward_skb retains the assumption that skb->len is the total length of the packet. I just measured this emperically by setting up a veth pair between two noop network namespaces setting and attempting a telnet connection between the two. I saw three packets in each direction and the byte counters were exactly 14*3 = 42 bytes high in each direction. I got the actual packet lengths with tcpdump. So remove the extra ETH_HLEN from the veth byte count totals. Signed-off-by: Eric W. Biederman --- drivers/net/veth.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 105d7f0..2de9b90 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -171,7 +171,7 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev) if (skb->ip_summed == CHECKSUM_NONE) skb->ip_summed = rcv_priv->ip_summed; - length = skb->len + ETH_HLEN; + length = skb->len; if (dev_forward_skb(rcv, skb) != NET_RX_SUCCESS) goto rx_drop; -- 1.7.4