xref: /linux/Documentation/networking/arcnet.rst (revision a4eb44a6435d6d8f9e642407a4a06f65eb90ca04)
1.. SPDX-License-Identifier: GPL-2.0
2
3======
4ARCnet
5======
6
7.. note::
8
9   See also arcnet-hardware.txt in this directory for jumper-setting
10   and cabling information if you're like many of us and didn't happen to get a
11   manual with your ARCnet card.
12
13Since no one seems to listen to me otherwise, perhaps a poem will get your
14attention::
15
16		This driver's getting fat and beefy,
17		But my cat is still named Fifi.
18
19Hmm, I think I'm allowed to call that a poem, even though it's only two
20lines.  Hey, I'm in Computer Science, not English.  Give me a break.
21
22The point is:  I REALLY REALLY REALLY REALLY REALLY want to hear from you if
23you test this and get it working.  Or if you don't.  Or anything.
24
25ARCnet 0.32 ALPHA first made it into the Linux kernel 1.1.80 - this was
26nice, but after that even FEWER people started writing to me because they
27didn't even have to install the patch.  <sigh>
28
29Come on, be a sport!  Send me a success report!
30
31(hey, that was even better than my original poem... this is getting bad!)
32
33
34.. warning::
35
36   If you don't e-mail me about your success/failure soon, I may be forced to
37   start SINGING.  And we don't want that, do we?
38
39   (You know, it might be argued that I'm pushing this point a little too much.
40   If you think so, why not flame me in a quick little e-mail?  Please also
41   include the type of card(s) you're using, software, size of network, and
42   whether it's working or not.)
43
44   My e-mail address is: apenwarr@worldvisions.ca
45
46These are the ARCnet drivers for Linux.
47
48This new release (2.91) has been put together by David Woodhouse
49<dwmw2@infradead.org>, in an attempt to tidy up the driver after adding support
50for yet another chipset. Now the generic support has been separated from the
51individual chipset drivers, and the source files aren't quite so packed with
52#ifdefs! I've changed this file a bit, but kept it in the first person from
53Avery, because I didn't want to completely rewrite it.
54
55The previous release resulted from many months of on-and-off effort from me
56(Avery Pennarun), many bug reports/fixes and suggestions from others, and in
57particular a lot of input and coding from Tomasz Motylewski.  Starting with
58ARCnet 2.10 ALPHA, Tomasz's all-new-and-improved RFC1051 support has been
59included and seems to be working fine!
60
61
62Where do I discuss these drivers?
63---------------------------------
64
65Tomasz has been so kind as to set up a new and improved mailing list.
66Subscribe by sending a message with the BODY "subscribe linux-arcnet YOUR
67REAL NAME" to listserv@tichy.ch.uj.edu.pl.  Then, to submit messages to the
68list, mail to linux-arcnet@tichy.ch.uj.edu.pl.
69
70There are archives of the mailing list at:
71
72	http://epistolary.org/mailman/listinfo.cgi/arcnet
73
74The people on linux-net@vger.kernel.org (now defunct, replaced by
75netdev@vger.kernel.org) have also been known to be very helpful, especially
76when we're talking about ALPHA Linux kernels that may or may not work right
77in the first place.
78
79
80Other Drivers and Info
81----------------------
82
83You can try my ARCNET page on the World Wide Web at:
84
85	http://www.qis.net/~jschmitz/arcnet/
86
87Also, SMC (one of the companies that makes ARCnet cards) has a WWW site you
88might be interested in, which includes several drivers for various cards
89including ARCnet.  Try:
90
91	http://www.smc.com/
92
93Performance Technologies makes various network software that supports
94ARCnet:
95
96	http://www.perftech.com/ or ftp to ftp.perftech.com.
97
98Novell makes a networking stack for DOS which includes ARCnet drivers.  Try
99FTPing to ftp.novell.com.
100
101You can get the Crynwr packet driver collection (including arcether.com, the
102one you'll want to use with ARCnet cards) from
103oak.oakland.edu:/simtel/msdos/pktdrvr. It won't work perfectly on a 386+
104without patches, though, and also doesn't like several cards.  Fixed
105versions are available on my WWW page, or via e-mail if you don't have WWW
106access.
107
108
109Installing the Driver
110---------------------
111
112All you will need to do in order to install the driver is::
113
114	make config
115		(be sure to choose ARCnet in the network devices
116		and at least one chipset driver.)
117	make clean
118	make zImage
119
120If you obtained this ARCnet package as an upgrade to the ARCnet driver in
121your current kernel, you will need to first copy arcnet.c over the one in
122the linux/drivers/net directory.
123
124You will know the driver is installed properly if you get some ARCnet
125messages when you reboot into the new Linux kernel.
126
127There are four chipset options:
128
129 1. Standard ARCnet COM90xx chipset.
130
131This is the normal ARCnet card, which you've probably got. This is the only
132chipset driver which will autoprobe if not told where the card is.
133It following options on the command line::
134
135 com90xx=[<io>[,<irq>[,<shmem>]]][,<name>] | <name>
136
137If you load the chipset support as a module, the options are::
138
139 io=<io> irq=<irq> shmem=<shmem> device=<name>
140
141To disable the autoprobe, just specify "com90xx=" on the kernel command line.
142To specify the name alone, but allow autoprobe, just put "com90xx=<name>"
143
144 2. ARCnet COM20020 chipset.
145
146This is the new chipset from SMC with support for promiscuous mode (packet
147sniffing), extra diagnostic information, etc. Unfortunately, there is no
148sensible method of autoprobing for these cards. You must specify the I/O
149address on the kernel command line.
150
151The command line options are::
152
153 com20020=<io>[,<irq>[,<node_ID>[,backplane[,CKP[,timeout]]]]][,name]
154
155If you load the chipset support as a module, the options are::
156
157 io=<io> irq=<irq> node=<node_ID> backplane=<backplane> clock=<CKP>
158 timeout=<timeout> device=<name>
159
160The COM20020 chipset allows you to set the node ID in software, overriding the
161default which is still set in DIP switches on the card. If you don't have the
162COM20020 data sheets, and you don't know what the other three options refer
163to, then they won't interest you - forget them.
164
165 3. ARCnet COM90xx chipset in IO-mapped mode.
166
167This will also work with the normal ARCnet cards, but doesn't use the shared
168memory. It performs less well than the above driver, but is provided in case
169you have a card which doesn't support shared memory, or (strangely) in case
170you have so many ARCnet cards in your machine that you run out of shmem slots.
171If you don't give the IO address on the kernel command line, then the driver
172will not find the card.
173
174The command line options are::
175
176 com90io=<io>[,<irq>][,<name>]
177
178If you load the chipset support as a module, the options are:
179 io=<io> irq=<irq> device=<name>
180
181 4. ARCnet RIM I cards.
182
183These are COM90xx chips which are _completely_ memory mapped. The support for
184these is not tested. If you have one, please mail the author with a success
185report. All options must be specified, except the device name.
186Command line options::
187
188 arcrimi=<shmem>,<irq>,<node_ID>[,<name>]
189
190If you load the chipset support as a module, the options are::
191
192 shmem=<shmem> irq=<irq> node=<node_ID> device=<name>
193
194
195Loadable Module Support
196-----------------------
197
198Configure and rebuild Linux.  When asked, answer 'm' to "Generic ARCnet
199support" and to support for your ARCnet chipset if you want to use the
200loadable module. You can also say 'y' to "Generic ARCnet support" and 'm'
201to the chipset support if you wish.
202
203::
204
205	make config
206	make clean
207	make zImage
208	make modules
209
210If you're using a loadable module, you need to use insmod to load it, and
211you can specify various characteristics of your card on the command
212line.  (In recent versions of the driver, autoprobing is much more reliable
213and works as a module, so most of this is now unnecessary.)
214
215For example::
216
217	cd /usr/src/linux/modules
218	insmod arcnet.o
219	insmod com90xx.o
220	insmod com20020.o io=0x2e0 device=eth1
221
222
223Using the Driver
224----------------
225
226If you build your kernel with ARCnet COM90xx support included, it should
227probe for your card automatically when you boot. If you use a different
228chipset driver complied into the kernel, you must give the necessary options
229on the kernel command line, as detailed above.
230
231Go read the NET-2-HOWTO and ETHERNET-HOWTO for Linux; they should be
232available where you picked up this driver.  Think of your ARCnet as a
233souped-up (or down, as the case may be) Ethernet card.
234
235By the way, be sure to change all references from "eth0" to "arc0" in the
236HOWTOs.  Remember that ARCnet isn't a "true" Ethernet, and the device name
237is DIFFERENT.
238
239
240Multiple Cards in One Computer
241------------------------------
242
243Linux has pretty good support for this now, but since I've been busy, the
244ARCnet driver has somewhat suffered in this respect. COM90xx support, if
245compiled into the kernel, will (try to) autodetect all the installed cards.
246
247If you have other cards, with support compiled into the kernel, then you can
248just repeat the options on the kernel command line, e.g.::
249
250	LILO: linux com20020=0x2e0 com20020=0x380 com90io=0x260
251
252If you have the chipset support built as a loadable module, then you need to
253do something like this::
254
255	insmod -o arc0 com90xx
256	insmod -o arc1 com20020 io=0x2e0
257	insmod -o arc2 com90xx
258
259The ARCnet drivers will now sort out their names automatically.
260
261
262How do I get it to work with...?
263--------------------------------
264
265NFS:
266	Should be fine linux->linux, just pretend you're using Ethernet cards.
267	oak.oakland.edu:/simtel/msdos/nfs has some nice DOS clients.  There
268	is also a DOS-based NFS server called SOSS.  It doesn't multitask
269	quite the way Linux does (actually, it doesn't multitask AT ALL) but
270	you never know what you might need.
271
272	With AmiTCP (and possibly others), you may need to set the following
273	options in your Amiga nfstab:  MD 1024 MR 1024 MW 1024
274	(Thanks to Christian Gottschling <ferksy@indigo.tng.oche.de>
275	for this.)
276
277	Probably these refer to maximum NFS data/read/write block sizes.  I
278	don't know why the defaults on the Amiga didn't work; write to me if
279	you know more.
280
281DOS:
282	If you're using the freeware arcether.com, you might want to install
283	the driver patch from my web page.  It helps with PC/TCP, and also
284	can get arcether to load if it timed out too quickly during
285	initialization.  In fact, if you use it on a 386+ you REALLY need
286	the patch, really.
287
288Windows:
289	See DOS :)  Trumpet Winsock works fine with either the Novell or
290	Arcether client, assuming you remember to load winpkt of course.
291
292LAN Manager and Windows for Workgroups:
293	These programs use protocols that
294	are incompatible with the Internet standard.  They try to pretend
295	the cards are Ethernet, and confuse everyone else on the network.
296
297	However, v2.00 and higher of the Linux ARCnet driver supports this
298	protocol via the 'arc0e' device.  See the section on "Multiprotocol
299	Support" for more information.
300
301	Using the freeware Samba server and clients for Linux, you can now
302	interface quite nicely with TCP/IP-based WfWg or Lan Manager
303	networks.
304
305Windows 95:
306	Tools are included with Win95 that let you use either the LANMAN
307	style network drivers (NDIS) or Novell drivers (ODI) to handle your
308	ARCnet packets.  If you use ODI, you'll need to use the 'arc0'
309	device with Linux.  If you use NDIS, then try the 'arc0e' device.
310	See the "Multiprotocol Support" section below if you need arc0e,
311	you're completely insane, and/or you need to build some kind of
312	hybrid network that uses both encapsulation types.
313
314OS/2:
315	I've been told it works under Warp Connect with an ARCnet driver from
316	SMC.  You need to use the 'arc0e' interface for this.  If you get
317	the SMC driver to work with the TCP/IP stuff included in the
318	"normal" Warp Bonus Pack, let me know.
319
320	ftp.microsoft.com also has a freeware "Lan Manager for OS/2" client
321	which should use the same protocol as WfWg does.  I had no luck
322	installing it under Warp, however.  Please mail me with any results.
323
324NetBSD/AmiTCP:
325	These use an old version of the Internet standard ARCnet
326	protocol (RFC1051) which is compatible with the Linux driver v2.10
327	ALPHA and above using the arc0s device. (See "Multiprotocol ARCnet"
328	below.)  ** Newer versions of NetBSD apparently support RFC1201.
329
330
331Using Multiprotocol ARCnet
332--------------------------
333
334The ARCnet driver v2.10 ALPHA supports three protocols, each on its own
335"virtual network device":
336
337	======  ===============================================================
338	arc0	RFC1201 protocol, the official Internet standard which just
339		happens to be 100% compatible with Novell's TRXNET driver.
340		Version 1.00 of the ARCnet driver supported _only_ this
341		protocol.  arc0 is the fastest of the three protocols (for
342		whatever reason), and allows larger packets to be used
343		because it supports RFC1201 "packet splitting" operations.
344		Unless you have a specific need to use a different protocol,
345		I strongly suggest that you stick with this one.
346
347	arc0e	"Ethernet-Encapsulation" which sends packets over ARCnet
348		that are actually a lot like Ethernet packets, including the
349		6-byte hardware addresses.  This protocol is compatible with
350		Microsoft's NDIS ARCnet driver, like the one in WfWg and
351		LANMAN.  Because the MTU of 493 is actually smaller than the
352		one "required" by TCP/IP (576), there is a chance that some
353		network operations will not function properly.  The Linux
354		TCP/IP layer can compensate in most cases, however, by
355		automatically fragmenting the TCP/IP packets to make them
356		fit.  arc0e also works slightly more slowly than arc0, for
357		reasons yet to be determined.  (Probably it's the smaller
358		MTU that does it.)
359
360	arc0s	The "[s]imple" RFC1051 protocol is the "previous" Internet
361		standard that is completely incompatible with the new
362		standard.  Some software today, however, continues to
363		support the old standard (and only the old standard)
364		including NetBSD and AmiTCP.  RFC1051 also does not support
365		RFC1201's packet splitting, and the MTU of 507 is still
366		smaller than the Internet "requirement," so it's quite
367		possible that you may run into problems.  It's also slower
368		than RFC1201 by about 25%, for the same reason as arc0e.
369
370		The arc0s support was contributed by Tomasz Motylewski
371		and modified somewhat by me.  Bugs are probably my fault.
372	======  ===============================================================
373
374You can choose not to compile arc0e and arc0s into the driver if you want -
375this will save you a bit of memory and avoid confusion when eg. trying to
376use the "NFS-root" stuff in recent Linux kernels.
377
378The arc0e and arc0s devices are created automatically when you first
379ifconfig the arc0 device.  To actually use them, though, you need to also
380ifconfig the other virtual devices you need.  There are a number of ways you
381can set up your network then:
382
383
3841. Single Protocol.
385
386   This is the simplest way to configure your network: use just one of the
387   two available protocols.  As mentioned above, it's a good idea to use
388   only arc0 unless you have a good reason (like some other software, ie.
389   WfWg, that only works with arc0e).
390
391   If you need only arc0, then the following commands should get you going::
392
393	ifconfig arc0 MY.IP.ADD.RESS
394	route add MY.IP.ADD.RESS arc0
395	route add -net SUB.NET.ADD.RESS arc0
396	[add other local routes here]
397
398   If you need arc0e (and only arc0e), it's a little different::
399
400	ifconfig arc0 MY.IP.ADD.RESS
401	ifconfig arc0e MY.IP.ADD.RESS
402	route add MY.IP.ADD.RESS arc0e
403	route add -net SUB.NET.ADD.RESS arc0e
404
405   arc0s works much the same way as arc0e.
406
407
4082. More than one protocol on the same wire.
409
410   Now things start getting confusing.  To even try it, you may need to be
411   partly crazy.  Here's what *I* did. :) Note that I don't include arc0s in
412   my home network; I don't have any NetBSD or AmiTCP computers, so I only
413   use arc0s during limited testing.
414
415   I have three computers on my home network; two Linux boxes (which prefer
416   RFC1201 protocol, for reasons listed above), and one XT that can't run
417   Linux but runs the free Microsoft LANMAN Client instead.
418
419   Worse, one of the Linux computers (freedom) also has a modem and acts as
420   a router to my Internet provider.  The other Linux box (insight) also has
421   its own IP address and needs to use freedom as its default gateway.  The
422   XT (patience), however, does not have its own Internet IP address and so
423   I assigned it one on a "private subnet" (as defined by RFC1597).
424
425   To start with, take a simple network with just insight and freedom.
426   Insight needs to:
427
428	- talk to freedom via RFC1201 (arc0) protocol, because I like it
429	  more and it's faster.
430	- use freedom as its Internet gateway.
431
432   That's pretty easy to do.  Set up insight like this::
433
434	ifconfig arc0 insight
435	route add insight arc0
436	route add freedom arc0	/* I would use the subnet here (like I said
437					to in "single protocol" above),
438					but the rest of the subnet
439					unfortunately lies across the PPP
440					link on freedom, which confuses
441					things. */
442	route add default gw freedom
443
444   And freedom gets configured like so::
445
446	ifconfig arc0 freedom
447	route add freedom arc0
448	route add insight arc0
449	/* and default gateway is configured by pppd */
450
451   Great, now insight talks to freedom directly on arc0, and sends packets
452   to the Internet through freedom.  If you didn't know how to do the above,
453   you should probably stop reading this section now because it only gets
454   worse.
455
456   Now, how do I add patience into the network?  It will be using LANMAN
457   Client, which means I need the arc0e device.  It needs to be able to talk
458   to both insight and freedom, and also use freedom as a gateway to the
459   Internet.  (Recall that patience has a "private IP address" which won't
460   work on the Internet; that's okay, I configured Linux IP masquerading on
461   freedom for this subnet).
462
463   So patience (necessarily; I don't have another IP number from my
464   provider) has an IP address on a different subnet than freedom and
465   insight, but needs to use freedom as an Internet gateway.  Worse, most
466   DOS networking programs, including LANMAN, have braindead networking
467   schemes that rely completely on the netmask and a 'default gateway' to
468   determine how to route packets.  This means that to get to freedom or
469   insight, patience WILL send through its default gateway, regardless of
470   the fact that both freedom and insight (courtesy of the arc0e device)
471   could understand a direct transmission.
472
473   I compensate by giving freedom an extra IP address - aliased 'gatekeeper' -
474   that is on my private subnet, the same subnet that patience is on.  I
475   then define gatekeeper to be the default gateway for patience.
476
477   To configure freedom (in addition to the commands above)::
478
479	ifconfig arc0e gatekeeper
480	route add gatekeeper arc0e
481	route add patience arc0e
482
483   This way, freedom will send all packets for patience through arc0e,
484   giving its IP address as gatekeeper (on the private subnet).  When it
485   talks to insight or the Internet, it will use its "freedom" Internet IP
486   address.
487
488   You will notice that we haven't configured the arc0e device on insight.
489   This would work, but is not really necessary, and would require me to
490   assign insight another special IP number from my private subnet.  Since
491   both insight and patience are using freedom as their default gateway, the
492   two can already talk to each other.
493
494   It's quite fortunate that I set things up like this the first time (cough
495   cough) because it's really handy when I boot insight into DOS.  There, it
496   runs the Novell ODI protocol stack, which only works with RFC1201 ARCnet.
497   In this mode it would be impossible for insight to communicate directly
498   with patience, since the Novell stack is incompatible with Microsoft's
499   Ethernet-Encap.  Without changing any settings on freedom or patience, I
500   simply set freedom as the default gateway for insight (now in DOS,
501   remember) and all the forwarding happens "automagically" between the two
502   hosts that would normally not be able to communicate at all.
503
504   For those who like diagrams, I have created two "virtual subnets" on the
505   same physical ARCnet wire.  You can picture it like this::
506
507
508	  [RFC1201 NETWORK]                   [ETHER-ENCAP NETWORK]
509      (registered Internet subnet)           (RFC1597 private subnet)
510
511			     (IP Masquerade)
512	  /---------------\         *            /---------------\
513	  |               |         *            |               |
514	  |               +-Freedom-*-Gatekeeper-+               |
515	  |               |    |    *            |               |
516	  \-------+-------/    |    *            \-------+-------/
517		  |            |                         |
518	       Insight         |                      Patience
519			   (Internet)
520
521
522
523It works: what now?
524-------------------
525
526Send mail describing your setup, preferably including driver version, kernel
527version, ARCnet card model, CPU type, number of systems on your network, and
528list of software in use to me at the following address:
529
530	apenwarr@worldvisions.ca
531
532I do send (sometimes automated) replies to all messages I receive.  My email
533can be weird (and also usually gets forwarded all over the place along the
534way to me), so if you don't get a reply within a reasonable time, please
535resend.
536
537
538It doesn't work: what now?
539--------------------------
540
541Do the same as above, but also include the output of the ifconfig and route
542commands, as well as any pertinent log entries (ie. anything that starts
543with "arcnet:" and has shown up since the last reboot) in your mail.
544
545If you want to try fixing it yourself (I strongly recommend that you mail me
546about the problem first, since it might already have been solved) you may
547want to try some of the debug levels available.  For heavy testing on
548D_DURING or more, it would be a REALLY good idea to kill your klogd daemon
549first!  D_DURING displays 4-5 lines for each packet sent or received.  D_TX,
550D_RX, and D_SKB actually DISPLAY each packet as it is sent or received,
551which is obviously quite big.
552
553Starting with v2.40 ALPHA, the autoprobe routines have changed
554significantly.  In particular, they won't tell you why the card was not
555found unless you turn on the D_INIT_REASONS debugging flag.
556
557Once the driver is running, you can run the arcdump shell script (available
558from me or in the full ARCnet package, if you have it) as root to list the
559contents of the arcnet buffers at any time.  To make any sense at all out of
560this, you should grab the pertinent RFCs. (some are listed near the top of
561arcnet.c).  arcdump assumes your card is at 0xD0000.  If it isn't, edit the
562script.
563
564Buffers 0 and 1 are used for receiving, and Buffers 2 and 3 are for sending.
565Ping-pong buffers are implemented both ways.
566
567If your debug level includes D_DURING and you did NOT define SLOW_XMIT_COPY,
568the buffers are cleared to a constant value of 0x42 every time the card is
569reset (which should only happen when you do an ifconfig up, or when Linux
570decides that the driver is broken).  During a transmit, unused parts of the
571buffer will be cleared to 0x42 as well.  This is to make it easier to figure
572out which bytes are being used by a packet.
573
574You can change the debug level without recompiling the kernel by typing::
575
576	ifconfig arc0 down metric 1xxx
577	/etc/rc.d/rc.inet1
578
579where "xxx" is the debug level you want.  For example, "metric 1015" would put
580you at debug level 15.  Debug level 7 is currently the default.
581
582Note that the debug level is (starting with v1.90 ALPHA) a binary
583combination of different debug flags; so debug level 7 is really 1+2+4 or
584D_NORMAL+D_EXTRA+D_INIT.  To include D_DURING, you would add 16 to this,
585resulting in debug level 23.
586
587If you don't understand that, you probably don't want to know anyway.
588E-mail me about your problem.
589
590
591I want to send money: what now?
592-------------------------------
593
594Go take a nap or something.  You'll feel better in the morning.
595