On 11/04/2012 04:35 AM, Eric W. Biederman wrote: > Tomas Pospisek <tpo@xxxxxxxxxxxxx> writes: > >> Hi again Michael, Pavel, Eric and mailing list >> >> (Cc: to Eric, Pavel and Linux Netdev List on behalf of Michael asking >> 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 Tomáš Pospíšek (tpo_deb@xxxxxxxxxxxxx), >> .\" 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, MA 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. > > As far as understanding and using them I think this text is a bit weak. > Perhaps something like: > > ip link add type veth creates a pair of directly connected ethernet > devices. What is transmited on one device is immediately received on > 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 particularly > interesting use case is to place one end of a veth pair in one network > namespace and another end of the veth pair in another network namespace > 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 just and ifindex of the peer, and the caller can do something useful with it if the peer is still in the same net namespace as the original device. But how would you find the peer device in case it already sits 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@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
