From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Emelyanov Subject: Re: veth.4 Date: Sun, 04 Nov 2012 05:43:36 +0400 Message-ID: <5095C848.9000501@parallels.com> References: <87zk2ytdbu.fsf@xmission.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <87zk2ytdbu.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Eric W. Biederman" Cc: Tomas Pospisek , "Michael Kerrisk (man-pages)" , "linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-man@vger.kernel.org On 11/04/2012 04:35 AM, Eric W. Biederman wrote: > Tomas Pospisek writes: >=20 >> Hi again Michael, Pavel, Eric and mailing list >> >> (Cc: to Eric, Pavel and Linux Netdev List on behalf of Michael askin= g >> for comment) >> >> Here's the revised veth(4) man page (the inline replies to Michael's >> critique are following the man page): >> >> ******************************************************************** >> .\" Copyright (c) 2012 Tom=C3=A1=C5=A1 Posp=C3=AD=C5=A1ek (tpo_deb@s= ourcepole.ch), >> .\" Fri, 03 Nov 2012 22:35:33 +0100 >> .\" >> .\" This is free documentation; you can redistribute it and/or >> .\" modify it under the terms of the GNU General Public License as >> .\" published by the Free Software Foundation; either version 2 of >> .\" the License, or (at your option) any later version. >> .\" >> .\" The GNU General Public License's references to "object code" >> .\" and "executables" are to be interpreted as the output of any >> .\" document formatting or typesetting system, including >> .\" intermediate and printed output. >> .\" >> .\" This manual is distributed in the hope that it will be useful, >> .\" but WITHOUT ANY WARRANTY; without even the implied warranty of >> .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> .\" GNU General Public License for more details. >> .\" >> .\" You should have received a copy of the GNU General Public >> .\" License along with this manual; if not, write to the Free >> .\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, M= A 02111, >> .\" USA. >> .\" >> .\" >> .TH veth 4 2012-11-02 "Linux" "Linux Programmer's Manual" >> .SH NAME >> veth \- Virtual Ethernet Device >> .SH DESCRIPTION >> The >> .B veth >> devices are virtual Ethernet devices. >> >> They can act as tunnels between network namespaces to create >> a bridge to a physical network device in another namespace, but >> can also be used as standalone network devices. >=20 > As far as understanding and using them I think this text is a bit wea= k. > Perhaps something like: >=20 > ip link add type veth creates a pair of directly connected ethernet > devices. What is transmited on one device is immediately received o= n > the other device. When either devices is down the link state of the > pair is down. veth device pairs are useful for combining the network > facilities of the kernel together in interesting ways. A particularl= y > interesting use case is to place one end of a veth pair in one networ= k > namespace and another end of the veth pair in another network namespa= ce > allowing communication between network namespaces. Ack > ethtool can be used to test if a networking device is a veth device, > and to find the peer network interface. This one requires clarification, I think. The ethtool will report you=20 just and ifindex of the peer, and the caller can do something useful=20 with it if the peer is still in the same net namespace as the original=20 device. But how would you find the peer device in case it already sits=20 in some other network namespace? > Eric Thanks, Pavel -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html