1.\" Copyright (c) 2004 Daniel Hartmeier 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.\" 8.\" - Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" - Redistributions in binary form must reproduce the above 11.\" copyright notice, this list of conditions and the following 12.\" disclaimer in the documentation and/or other materials provided 13.\" with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16.\" "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18.\" FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19.\" COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 22.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 23.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 25.\" ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26.\" POSSIBILITY OF SUCH DAMAGE. 27.\" 28.\" $NetBSD: cdce.4,v 1.4 2004/12/08 18:35:56 peter Exp $ 29.\" 30.Dd May 26, 2025 31.Dt CDCE 4 32.Os 33.Sh NAME 34.Nm cdce 35.Nd "USB Communication Device Class Ethernet (CDC ECM/NCM) driver" 36.Sh SYNOPSIS 37To compile this driver into the kernel, 38place the following lines in your 39kernel configuration file: 40.Bd -ragged -offset indent 41.Cd "device uhci" 42.Cd "device ohci" 43.Cd "device usb" 44.Cd "device miibus" 45.Cd "device uether" 46.Cd "device cdce" 47.Ed 48.Pp 49Mobile Devices (eg. Huawei E3372, E5573 and others) 50may need additionally the u3g command port: 51.Bd -ragged -offset indent 52.Cd "device ucom" 53.Cd "device u3g" 54.Ed 55.Pp 56Alternatively, to load the driver as a 57module at boot time, place the following line in 58.Xr loader.conf 5 : 59.Bd -literal -offset indent 60if_cdce_load="YES" 61.Ed 62.Sh DESCRIPTION 63The 64.Nm 65driver provides support for USB Host-to-Host (aka USB-to-USB) and 66USB-to-Ethernet bridges based on the USB Communication Device Class 67Ethernet Control Model (CDC ECM) and Network Control Model (CDC NCM) 68specifications. 69It also provides device-side CDC ECM support. 70.Pp 71The USB bridge appears as a regular network interface on both sides, 72transporting Ethernet frames. 73.Pp 74For more information on configuring this device, see 75.Xr ifconfig 8 . 76.Pp 77USB 1.x bridges support speeds of up to 12Mbps, and USB 2.0 speeds of 78up to 480Mbps. 79.Pp 80Packets are 81received and transmitted over separate USB bulk transfer endpoints. 82.Pp 83The 84.Nm 85driver does not support different media types or options. 86.Pp 87Mobile 88.Nm 89Network Devices may need a connect command sequence via u3g 90serial command port before they activate the NCM/ECM/ACM network 91interface. 92For example: 93.Dl echo 'AT^NDISUP=1,1,"internet"' > /dev/cuaU[0].0 94where 95.Dq internet 96is your providers apn name. 97.Sh HARDWARE 98The 99.Nm 100driver supports USB Ethernet interfaces implementing the 101USB Communication Device Class Ethernet Control Model (CDC ECM) or 102Network Control Model (CDC NCM) protocol, such as: 103.Pp 104.Bl -bullet -compact 105.It 106Android USB tethering 107.It 108iPhone USB tethering 109.It 110Prolific PL-2501 Host-to-Host Bridge Controller 111.It 112Sharp Zaurus PDA 113.It 114Terayon TJ-715 DOCSIS Cable Modem 115.It 116Huawei 3G/4G LTE (eg. E3372, E5573) and other mobile network devices 117.El 118.Sh DIAGNOSTICS 119.Bl -diag 120.It "cdce%d: no union descriptor" 121The driver could not fetch an interface descriptor from the USB 122device. 123For a manually added USB vendor/product, the CDCE_NO_UNION flag 124can be tried to work around the missing descriptor. 125.It "cdce%d: no data interface" 126.It "cdce%d: could not read endpoint descriptor" 127.It "cdce%d: unexpected endpoint" 128.It "cdce%d: could not find data bulk in/out" 129For a manually added USB vendor/product, these errors indicate 130that the bridge is not compatible with the driver. 131.It "cdce%d: watchdog timeout" 132A packet was queued for transmission and a transmit command was 133issued, however the device failed to acknowledge the transmission 134before a timeout expired. 135.It "cdce%d: no memory for rx list -- packet dropped!" 136Memory allocation through MGETHDR or MCLGET failed, the system 137is running low on mbufs. 138.It "cdce%d: abort/close rx/tx pipe failed" 139.It "cdce%d: rx/tx list init failed" 140.It "cdce%d: open rx/tx pipe failed" 141.It "cdce%d: usb error on rx/tx" 142.El 143.Sh SEE ALSO 144.Xr arp 4 , 145.Xr cdceem 4 , 146.Xr intro 4 , 147.Xr ipheth 4 , 148.Xr netintro 4 , 149.Xr u3g 4 , 150.Xr ucom 4 , 151.Xr urndis 4 , 152.Xr usb 4 , 153.Xr ifconfig 8 154.Rs 155.%T "Universal Serial Bus Class Definitions for Communication Devices" 156.%U http://www.usb.org/developers/devclass_docs/usbcdc11.pdf 157.Re 158.Rs 159.%T "Data sheet Prolific PL-2501 Host-to-Host Bridge/Network Controller" 160.%U http://tech.prolific.com.tw/visitor/fcabdl.asp?fid=20679530 161.Re 162.Sh HISTORY 163The 164.Nm 165device driver first appeared in 166.Ox 3.6 , 167.Nx 3.0 168and 169.Fx 6.0 . 170.Sh AUTHORS 171.An -nosplit 172The 173.Nm 174driver was written by 175.An Craig Boston Aq Mt craig@tobuj.gank.org 176based on the 177.Xr aue 4 178driver written by 179.An Bill Paul Aq Mt wpaul@windriver.com 180and ported to 181.Ox 182by 183.An Daniel Hartmeier Aq Mt dhartmei@openbsd.org . 184.Sh CAVEATS 185Many USB devices notoriously fail to report their class and interfaces 186correctly. 187Undetected products might work flawlessly when their vendor and product IDs 188are added to the driver manually. 189