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.\" 28.\" $FreeBSD$ 29.\" $Id: $ 30.\" 31.Dd January 9, 2019 32.Dt VALE 4 33.Os 34.Sh NAME 35.Nm vale 36.Nd a very fast Virtual Local Ethernet using the netmap API 37.Sh SYNOPSIS 38.Cd device netmap 39.Sh DESCRIPTION 40.Nm 41is a feature of the 42.Xr netmap 4 43module that implements multiple Virtual switches that can 44be used to interconnect netmap clients, including traffic 45sources and sinks, packet forwarders, userspace firewalls, 46and so on. 47.Pp 48.Nm 49is implemented completely in software, and is extremely fast. 50On a modern machine it can move almost 20 Million packets per 51second (Mpps) per core with small frames, and about 70 Gbit/s 52with 1500 byte frames. 53.Sh OPERATION 54.Nm 55dynamically creates switches and ports as clients connect 56to it using the 57.Xr netmap 4 58API. 59.Pp 60.Nm 61ports are named 62.Pa valeSSS:PPP 63where 64.Pa vale 65is the prefix indicating a VALE switch rather than a standard interface, 66.Pa SSS 67indicates a specific switch (the colon is a separator), 68and 69.Pa PPP 70indicates a port within the switch. 71Both SSS and PPP have the form [0-9a-zA-Z_]+ , the string cannot 72exceed IFNAMSIZ characters, and PPP cannot be the name of any 73existing OS network interface. 74.Pp 75See 76.Xr netmap 4 77for details on the API. 78.Ss LIMITS 79.Nm 80currently supports up to 4 switches, 16 ports per switch, with 811024 buffers per port. 82These hard limits will be 83changed to sysctl variables in future releases. 84.Sh SYSCTL VARIABLES 85.Nm 86uses the following sysctl variables to control operation: 87.Bl -tag -width dev.netmap.verbose 88.It dev.netmap.bridge_batch 89The maximum number of packets processed internally 90in each iteration. 91Defaults to 1024, use lower values to trade latency 92with throughput. 93.It dev.netmap.verbose 94Set to non-zero values to enable in-kernel diagnostics. 95.El 96.Sh EXAMPLES 97Create one switch, with a traffic generator connected to one 98port, and a netmap-enabled tcpdump instance on another port: 99.Bd -literal -offset indent 100tcpdump -ni valea:1 & 101pkt-gen -i valea:0 -f tx & 102.Ed 103.Pp 104Create two switches, 105each connected to two qemu machines on different ports. 106.Bd -literal -offset indent 107qemu -net nic -net netmap,ifname=vale1:a ... & 108qemu -net nic -net netmap,ifname=vale1:b ... & 109qemu -net nic -net netmap,ifname=vale2:c ... & 110qemu -net nic -net netmap,ifname=vale2:d ... & 111.Ed 112.Sh SEE ALSO 113.Xr netmap 4 114.Pp 115Luigi Rizzo, Giuseppe Lettieri: VALE, a switched ethernet for virtual machines, 116June 2012, http://info.iet.unipi.it/~luigi/vale/ 117.Sh AUTHORS 118.An -nosplit 119The 120.Nm 121switch was designed and implemented in 2012 by 122.An Luigi Rizzo 123and 124.An Giuseppe Lettieri 125at the Universita` di Pisa. 126.Pp 127.Nm 128was funded by the European Commission within FP7 Projects 129CHANGE (257422) and OPENLAB (287581). 130