1.\" 2.\" Copyright (c) 2008 The DragonFly Project. All rights reserved. 3.\" 4.\" This code is derived from software contributed to The DragonFly Project 5.\" by Matthew Dillon <dillon@backplane.com> 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in 15.\" the documentation and/or other materials provided with the 16.\" distribution. 17.\" 3. Neither the name of The DragonFly Project nor the names of its 18.\" contributors may be used to endorse or promote products derived 19.\" from this software without specific, prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24.\" FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25.\" COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26.\" INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" $DragonFly: src/usr.sbin/vknetd/vknetd.8,v 1.3 2008/05/31 12:04:15 swildner Exp $ 35.\" 36.Dd May 21, 2009 37.Dt VKNETD 8 38.Os 39.Sh NAME 40.Nm vknetd 41.Nd create a bridged network for (typically user-run) vkernels 42.Sh SYNOPSIS 43.Nm 44.Op Fl cdU 45.Op Fl b Ar bridgeN 46.Op Fl p Ar socket_path 47.Op Fl t Ar tapN 48.Op Ar address Ns / Ns Ar cidrbits 49.Sh DESCRIPTION 50The 51.Nm 52utility creates a virtualized bridged network suitable for vkernel use. 53The utility was created to simplify 54.Nm vkernel 55operations and to allow user-run 56vkernels to have access to a network. 57General use is to specify a large 10-dot network which multiple vkernels are 58then able to connect to, and backfeed the whole mess to a TAP interface. 59.Pp 60A 61.Nm vkernel 62would make use of the virtualized network by specifying 63.Fl I Ar /var/run/vknet 64instead of a 65.Xr tap 4 66interface. 67Any number of vkernels may connect to the virtual network. 68.Pp 69.Nm 70Implements a simple bridge for all entities connected to it. 71A cache 72of MAC addresses is built up (just like an ethernet switch does) and matching 73packets will be forwarded directly to the proper 74.Sq port 75(connected clients or TAP interface). 76Unknown MACs will be broadcast. 77.Pp 78The following options are available: 79.Bl -tag -width flag 80.It Fl c 81Connect into the bridge and monitor activity. 82This option currently only monitors broadcast packets. 83Packets with cached MACs are not monitored. 84.It Fl d 85Debug mode. 86Do not go into the background. 87.It Fl U 88Unsecure mode. 89Act as a pure bridge and do not try to secure the IP 90space from host visibility. 91This is typically used with the 92.Fl b 93option to directly bridge 94.Nm 95into the host rather than operating it as a separate subnet. 96.It Fl b Ar bridgeN 97The 98.Xr tap 4 99interface 100will be bridged into the specified bridge. 101.It Fl p Ar socket_path 102Specify where to create the unix domain socket in the filesystem space. 103By default the socket is called 104.Pa /var/run/vknet . 105.It Fl t Ar tapN 106Specify a particular 107.Xr tap 4 108interface to use. 109If not specified, 110.Nm 111will search for an unused TAP interface. 112.It Ar address Ns / Ns Ar cidrbits 113When operating in secure mode (which is the default), a CIDR block must be 114specified. 115It is optional in unsecure mode. 116The 117.Ar address 118is the address you wish to assign to the TAP 119interface and will sit on both the host and virtual networks if not bridged. 120The 121.Ar cidrbits 122is the number of bits representing the virtual subnet. 123For example, 12410.1.0.1/24 places the TAP interface on 10.1.0.1 and gives you an 8 bit 125subnet capable of handling 254 hosts. 126An address of 0.0.0.0 is allowed as a special case in secure mode so that 127bootp ( 128.Xr dhclient 8 ) 129can get through. 130.El 131.Sh FILES 132.Bl -tag -width ".Pa /var/run/vknet" -compact 133.It Pa /dev/tap* 134TAP interface used to route packets from userland providers back into the 135real machine. 136If not otherwise specified an unused TAP interface will be selected. 137.It Pa /var/run/vknet 138Default socket 139.Nm 140sits on waiting for connections. 141.El 142.Sh EXAMPLES 143.Dl "vknetd 10.1.0.1/16" 144.Sh REQUIREMENTS 145.Nm 146requires that the 147.Nm if_tap 148and 149.Nm if_bridge 150modules be loaded. 151In addition, a 152.Dq vknet 153group must exist in 154.Pa /etc/groups . 155.Sh SEE ALSO 156.Xr vknet 1 , 157.Xr bridge 4 , 158.Xr tap 4 , 159.Xr vke 4 , 160.Xr vkernel 7 , 161.Xr dhclient 8 162.Sh HISTORY 163The 164.Nm 165command was written by Matthew Dillon and first appeared in 166.Dx 1.13 167in May 2008. 168.Sh BUGS 169.Nm 170defaults to secure mode and will prevent IP spoofing, but the security 171does not yet handle ARP issues so ARP spoofing can be used to create a 172denial of service attack on the host network. 173.Pp 174.Nm 175does not currently implement a timeout for its MAC cache. 176