From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gaofeng Subject: Re: pskb_copy() in tcp_transmit_skb() Date: Tue, 13 Sep 2011 17:29:25 +0800 Message-ID: <4E6F2275.2050902@cn.fujitsu.com> References: <201109131221.37561.christoph.paasch@uclouvain.be> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: christoph.paasch@uclouvain.be Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:56457 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750777Ab1IMJ3E convert rfc822-to-8bit (ORCPT ); Tue, 13 Sep 2011 05:29:04 -0400 In-Reply-To: <201109131221.37561.christoph.paasch@uclouvain.be> Sender: netdev-owner@vger.kernel.org List-ID: =E4=BA=8E 2011=E5=B9=B409=E6=9C=8813=E6=97=A5 17:21, Christoph Paasch= =E5=86=99=E9=81=93: > Hi, > > I'm trying to understand the reason for the possible call to pskb_cop= y() in > tcp_transmit_skb(). > I don't find, where we may have a cloned skb entering tcp_transmit_sk= b(). > > The original pskb_copy() came from tcp_retransmit_skb() (commit > dfb4b9dceb35c567a595ae5e9d035cfda044a103). > But from that point, the git-history does not show where the pskb_cop= y() is > coming from. > > > Does somebody has an idea, how a cloned skb can be passed to > tcp_transmit_skb() and thus trigger this call to pskb_copy(). > > > Thanks for your help, > Christoph > > > -- > Christoph Paasch > PhD Student > > IP Networking Lab --- http://inl.info.ucl.ac.be > MultiPath TCP in the Linux Kernel --- http://inl.info.ucl.ac.be/mptcp > Universit=C3=A9 Catholique de Louvain > > www.rollerbulls.be > -- > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > maybe nat,nat can change the tcp packet header