From: Eric Dumazet <eric.dumazet@gmail.com>
To: Rick Jones <rick.jones2@hp.com>
Cc: Vijay Subramanian <subramanian.vijay@gmail.com>,
tcpdump-workers@lists.tcpdump.org, netdev@vger.kernel.org
Subject: Re: twice past the taps, thence out to net?
Date: Thu, 15 Dec 2011 19:54:37 +0100 [thread overview]
Message-ID: <1323975277.2769.20.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> (raw)
In-Reply-To: <4EEA3D58.5010101@hp.com>
Le jeudi 15 décembre 2011 à 10:32 -0800, Rick Jones a écrit :
> > More exactly, we call dev_queue_xmit_nit() from dev_hard_start_xmit()
> > _before_ giving skb to device driver.
> >
> > If device driver returns NETDEV_TX_BUSY, and a qdisc was setup on the
> > device, packet is requeued.
> >
> > Later, when queue is allowed to send again packets, packet is
> > retransmitted (and traced a second time in dev_queue_xmit_nit())
>
> Is this then an unintended consequence bug, or a known feature?
>
Its a well known feature, some people attempted to remove it ;)
http://answers.softpicks.net/answers/topic/-PATCH-tcpdump-may-trace-some-outbound-packets-twice--2204640-1.htm
prev parent reply other threads:[~2011-12-15 18:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-14 19:27 twice past the taps, thence out to net? Rick Jones
2011-12-15 0:58 ` Benjamin Poirier
2011-12-15 2:12 ` Vijay Subramanian
2011-12-15 17:43 ` Eric Dumazet
2011-12-15 18:32 ` Rick Jones
2011-12-15 18:44 ` Stephen Hemminger
2011-12-15 19:00 ` Eric Dumazet
2011-12-15 22:22 ` Rick Jones
2011-12-16 4:27 ` Eric Dumazet
2011-12-16 18:28 ` Jesse Brandeburg
2011-12-16 19:34 ` Eric Dumazet
2011-12-16 19:35 ` Rick Jones
2011-12-16 19:44 ` Eric Dumazet
2011-12-20 21:21 ` Wyborny, Carolyn
2011-12-15 18:54 ` Eric Dumazet [this message]
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