Various pages: [GPL-1.0-or-later] Use SPDX-License-Identifier

[thirdparty/man-pages.git] / man4 / veth.4

diff --git a/man4/veth.4 b/man4/veth.4
index c0c47d829811591360ebef3ca09b3bfa06f69437..7b9064720f3fc07ec3a4f88ad2a736e1cc36d7bb 100644 (file)
--- a/man4/veth.4
+++ b/man4/veth.4
@@ -2,6 +2,7 @@
 .\"     Fri, 03 Nov 2012 22:35:33 +0100
 .\" and Copyright (c) 2012 Eric W. Biederman <ebiederm@xmission.com>
 .\"
+.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
 .\" 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
@@ -21,9 +22,10 @@
 .\" License along with this manual; if not, write to the Free
 .\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
 .\" USA.
+.\" %%%LICENSE_END
 .\"
 .\"
-.TH veth 4 2017-10-03 "Linux" "Linux Programmer's Manual"
+.TH VETH 4 2021-03-22 "Linux" "Linux Programmer's Manual"
 .SH NAME
 veth \- Virtual Ethernet Device
 .SH DESCRIPTION
@@ -49,11 +51,10 @@ In the above,
 and
 .I p2-name
 are the names assigned to the two connected end points.
-interconnected with each other.
 .PP
 Packets transmitted on one device in the pair are immediately received on
 the other device.
-When either devices is down the link state of the pair is down. 
+When either device is down, the link state of the pair is down.
 .PP
 .B veth
 device pairs are useful for combining the network
@@ -62,13 +63,44 @@ A particularly interesting use case is to place one end of a
 .B veth
 pair in one network namespace and the other end in another network namespace,
 thus allowing communication between network namespaces.
+To do this, one can provide the
+.B netns
+parameter when creating the interfaces:
+.PP
+.in +4n
+.EX
+# ip link add <p1\-name> netns <p1\-ns> type veth peer <p2\-name> netns <p2\-ns>
+.EE
+.in
+.PP
+or, for an existing
+.B veth
+pair, move one side to the other namespace:
+.PP
+.in +4n
+.EX
+# ip link set <p2\-name> netns <p2\-ns>
+.EE
+.in
 .PP
 .BR ethtool (8)
-can be used to test if a networking device is a
+can be used to find the peer of a
 .B veth
-device, and to find the peer network interface.
+network interface, using commands something like:
+.PP
+.in +4n
+.EX
+# \fBip link add ve_A type veth peer name ve_B\fP   # Create veth pair
+# \fBethtool \-S ve_A\fP         # Discover interface index of peer
+NIC statistics:
+     peer_ifindex: 16
+# \fBip link | grep \(aq\(ha16:\(aq\fP   # Look up interface
+16: ve_B@ve_A: <BROADCAST,MULTICAST,M\-DOWN> mtu 1500 qdisc ...
+.EE
+.in
 .SH "SEE ALSO"
 .BR clone (2),
+.BR network_namespaces (7),
 .BR ip (8),
-.BR ip-link (8),
-.BR ip-netns (8)
+.BR ip\-link (8),
+.BR ip\-netns (8)