1.\" Copyright (c) 2012 Luigi Rizzo, Universita` di Pisa 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" This document is derived in part from the enet man page (enet.4) 26.\" distributed with 4.3BSD Unix. 27.\" $Id: $ 28.\" 29.Dd August 30, 2024 30.Dt VALE 4 31.Os 32.Sh NAME 33.Nm vale 34.Nd a very fast Virtual Local Ethernet using the netmap API 35.Sh SYNOPSIS 36.Cd device netmap 37.Sh DESCRIPTION 38.Nm 39is a feature of the 40.Xr netmap 4 41module that implements multiple Virtual switches that can 42be used to interconnect netmap clients, including traffic 43sources and sinks, packet forwarders, userspace firewalls, 44and so on. 45.Pp 46.Nm 47is implemented completely in software, and is extremely fast. 48On a modern machine it can move almost 20 Million packets per 49second (Mpps) per core with small frames, and about 70 Gbit/s 50with 1500 byte frames. 51.Sh OPERATION 52.Nm 53dynamically creates switches and ports as clients connect 54to it using the 55.Xr netmap 4 56API. 57.Pp 58.Nm 59ports are named 60.Pa valeSSS:PPP 61where 62.Pa vale 63is the prefix indicating a VALE switch rather than a standard interface, 64.Pa SSS 65indicates a specific switch (the colon is a separator), 66and 67.Pa PPP 68indicates a port within the switch. 69Both SSS and PPP have the form [0-9a-zA-Z_]+ , the string cannot 70exceed IFNAMSIZ characters, and PPP cannot be the name of any 71existing OS network interface. 72.Pp 73See 74.Xr netmap 4 75for details on the API. 76.Ss LIMITS 77.Nm 78currently supports up to 254 ports per switch. The maximum 79number of switches is provided by the max_bridges sysctl variable. 80.Sh SYSCTL VARIABLES 81See 82.Xr netmap 4 83for a list of sysctl variables that affect 84.Nm 85bridges. 86.Sh EXAMPLES 87Create one switch, with a traffic generator connected to one 88port, and a netmap-enabled tcpdump instance on another port: 89.Bd -literal -offset indent 90tcpdump -ni valea:1 & 91pkt-gen -i valea:0 -f tx & 92.Ed 93.Pp 94Create two switches, 95each connected to two qemu machines on different ports. 96.Bd -literal -offset indent 97qemu -net nic -net netmap,ifname=vale1:a ... & 98qemu -net nic -net netmap,ifname=vale1:b ... & 99qemu -net nic -net netmap,ifname=vale2:c ... & 100qemu -net nic -net netmap,ifname=vale2:d ... & 101.Ed 102.Sh SEE ALSO 103.Xr netmap 4 , 104.Xr valectl 8 105.Pp 106Luigi Rizzo, Giuseppe Lettieri: VALE, a switched ethernet for virtual machines, 107June 2012, http://info.iet.unipi.it/~luigi/vale/ 108.Sh AUTHORS 109.An -nosplit 110The 111.Nm 112switch was designed and implemented in 2012 by 113.An Luigi Rizzo 114and 115.An Giuseppe Lettieri 116at the Universita` di Pisa. 117.Pp 118.Nm 119was funded by the European Commission within FP7 Projects 120CHANGE (257422) and OPENLAB (287581). 121