1.\" $NetBSD: bah.4,v 1.19 2017/02/18 22:39:00 wiz Exp $ 2.\" 3.\" Copyright (c) 1995, 1997 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Ignatios Souvatzis. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.\" The following requests are required for all man pages. 31.Dd February 17, 2017 32.Dt BAH 4 amiga 33.Os 34.Sh NAME 35.Nm bah 36.Nd ARCnet network driver for SMC COM90C26 based boards 37.Sh SYNOPSIS 38.Cd "bah* at zbus0" 39.Sh DESCRIPTION 40The 41.Nm 42interface provides access to the 2.5 Mb/s ARCnet network via the 43.Tn SMC 44COM90C26 + COM90C32 45ARCnet chip set. 46.Pp 47Each of the host's network addresses 48is specified at boot time with an 49.Dv SIOCSIFADDR 50.Xr ioctl 2 . 51The interface MTU is 507 for protocols that do not use link level fragmentation 52and 60480 bytes for the others. The routing layer may specify additional 53limits. 54.br 55Currently supported protocols are IPv4(+ARP), and IPv6. 56.Sh IP VERSION 4 CONSIDERATIONS 57When the NOARP flag is set on the 58.Nm 59interface, 60it does not employ the address resolution protocol described in 61.Xr arp 4 62to dynamically map between Internet and Ethernet addresses on the local 63network. Instead, it uses the least significant 8 bits of the IP address 64as hardware address, as described in RFC 1051 and RFC 1201. 65.Pp 66With the IFF_LINK0 flag cleared, IP and ARP encoding is done according to the 67deprecated, but popular among Amiga users, RFC 1051 encoding (that 68is, with simple header, packet type 240 / 241), and the MTU is 507. 69.Pp 70With the IFF_LINK0 flag set, IP/ARP/RARP encoding is done according to RFC 1201 71(that is, with Packet Header Definition Standard header and packet type 72212/213). The MTU is normally 1500. 73.Pp 74When switching between the two modes, do a 75.Cd ifconfig interfacename down up 76to switch the MTU. 77.Pp 78When the IFF_LINK2 flag is set, ARP packets are sent with the protocol type 79encoded as it would be in the ARCnet header, and decoded to the right protocol 80encoding on reception. According to "assigned numbers", this is wrong, but 81some legacy software (namely, AmiTCP 3.0beta) shows this bug. 82.Sh HARDWARE 83The 84.Nm 85interface supports the following Zorro II expansion cards: 86.Bl -tag -width "AMERISTAR" -offset indent 87.It Em A2060 88Commodore's ARCnet card, manufacturer\ 514, product\ 9 89.It Em AMERISTAR 90Ameristar's ARCnet card, manufacturer\ 1053, product\ 9 91.El 92.Sh SEE ALSO 93.Xr amiga/intro 4 , 94.Xr arp 4 , 95.Xr inet 4 , 96.Xr ifconfig 8 97.Rs 98.%J RFC 99.%N 1051 100.%D March 1988 101.%T "Standard for the transmission of IP datagrams and ARP packets over ARCNET networks." 102.%A P.A. Prindeville 103.Re 104.Rs 105.%J RFC 106.%N 1201 107.%T "Transmitting IP traffic over ARCNET networks." 108.%A D. Provan 109.%D February 1991 110.Re 111.Rs 112.%J RFC 113.%N 2497 114.%T "Transmission of IPv6 Packets over ARCnet Networks." 115.%A I. Souvatzis 116.%D January 1999 117.Re 118.Pp 119ARCnet Packet Header Definition Standard, Novell Inc., 1989 120.Sh STANDARDS 121RFC 1051/RFC1201 with ARP, or without, using direct mapping of lower 8 IP 122address bits instead. 123.Sh HISTORY 124The 125.Tn Amiga 126.Nm 127interface first appeared in 128.Nx 1.1 . 129ARP support was added in 130.Nx 1.3 . 131.Sh AUTHORS 132.An Ignatios Souvatzis 133