1.\" 2.\" Copyright (c) 2016 Alexander Motin <mav@FreeBSD.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.Dd September 2, 2017 27.Dt IF_NTB 4 28.Os 29.Sh NAME 30.Nm if_ntb 31.Nd Virtual Ethernet interface for Non-Transparent Bridges 32.Sh SYNOPSIS 33To compile this driver into your kernel, 34place the following lines in your kernel configuration file: 35.Bd -ragged -offset indent 36.Cd "device ntb" 37.Cd "device ntb_transport" 38.Cd "device if_ntb" 39.Ed 40.Pp 41Or, to load the driver as a module at boot, place the following line in 42.Xr loader.conf 5 : 43.Bd -literal -offset indent 44if_ntb_load="YES" 45.Ed 46.Pp 47The following tunables are settable from the 48.Xr loader 8 : 49.Bl -ohang 50.It Va hw.if_ntb.num_queues 51Limits maximal number of queues per interface. 52Default is unlimited. 53.El 54.Sh DESCRIPTION 55The 56.Nm 57driver attaches on top of the 58.Xr ntb_transport 4 59driver to utilize one or more of its packet queues to create virtual 60Ethernet network interface between the systems. 61Typical MTU for the interface is about 64KB to reduce overhead. 62Default MAC address for the interface is randomly generated. 63.Pp 64The 65.Nm 66driver does not implement any real hardware offload, but since PCIe link is 67protected by CRC32, in some situations it may be possible to save some CPU 68cycles by enabling fake checksum offload on both link sides via setting 69.Cm rxcsum 70and 71.Cm txcsum 72interface options. 73.Sh SEE ALSO 74.Xr ntb_transport 4 75.Sh AUTHORS 76.An -nosplit 77The 78.Nm 79driver was developed by Intel and originally written by 80.An Carl Delsey Aq Mt carl@FreeBSD.org . 81Later improvements were done by 82.An Conrad E. Meyer Aq Mt cem@FreeBSD.org 83and 84.An Alexander Motin Aq Mt mav@FreeBSD.org . 85.Sh BUGS 86Linux supports only one queue per interface, so manual configuration 87may be required for compatibility. 88