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TOMOYO Linux Cross Reference
Linux/Documentation/networking/arcnet.rst

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  1 .. SPDX-License-Identifier: GPL-2.0
  2 
  3 ======
  4 ARCnet
  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 
 13 Since no one seems to listen to me otherwise, perhaps a poem will get your
 14 attention::
 15 
 16                 This driver's getting fat and beefy,
 17                 But my cat is still named Fifi.
 18 
 19 Hmm, I think I'm allowed to call that a poem, even though it's only two
 20 lines.  Hey, I'm in Computer Science, not English.  Give me a break.
 21 
 22 The point is:  I REALLY REALLY REALLY REALLY REALLY want to hear from you if
 23 you test this and get it working.  Or if you don't.  Or anything.
 24 
 25 ARCnet 0.32 ALPHA first made it into the Linux kernel 1.1.80 - this was
 26 nice, but after that even FEWER people started writing to me because they
 27 didn't even have to install the patch.  <sigh>
 28 
 29 Come 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 
 46 These are the ARCnet drivers for Linux.
 47 
 48 This 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
 50 for yet another chipset. Now the generic support has been separated from the
 51 individual 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
 53 Avery, because I didn't want to completely rewrite it.
 54 
 55 The 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
 57 particular a lot of input and coding from Tomasz Motylewski.  Starting with
 58 ARCnet 2.10 ALPHA, Tomasz's all-new-and-improved RFC1051 support has been
 59 included and seems to be working fine!
 60 
 61 
 62 Where do I discuss these drivers?
 63 ---------------------------------
 64 
 65 Tomasz has been so kind as to set up a new and improved mailing list.
 66 Subscribe by sending a message with the BODY "subscribe linux-arcnet YOUR
 67 REAL NAME" to listserv@tichy.ch.uj.edu.pl.  Then, to submit messages to the
 68 list, mail to linux-arcnet@tichy.ch.uj.edu.pl.
 69 
 70 There are archives of the mailing list at:
 71 
 72         http://epistolary.org/mailman/listinfo.cgi/arcnet
 73 
 74 The people on linux-net@vger.kernel.org (now defunct, replaced by
 75 netdev@vger.kernel.org) have also been known to be very helpful, especially
 76 when we're talking about ALPHA Linux kernels that may or may not work right
 77 in the first place.
 78 
 79 
 80 Other Drivers and Info
 81 ----------------------
 82 
 83 You can try my ARCNET page on the World Wide Web at:
 84 
 85         http://www.qis.net/~jschmitz/arcnet/
 86 
 87 Also, SMC (one of the companies that makes ARCnet cards) has a WWW site you
 88 might be interested in, which includes several drivers for various cards
 89 including ARCnet.  Try:
 90 
 91         http://www.smc.com/
 92 
 93 Performance Technologies makes various network software that supports
 94 ARCnet:
 95 
 96         http://www.perftech.com/ or ftp to ftp.perftech.com.
 97 
 98 Novell makes a networking stack for DOS which includes ARCnet drivers.  Try
 99 FTPing to ftp.novell.com.
100 
101 You can get the Crynwr packet driver collection (including arcether.com, the
102 one you'll want to use with ARCnet cards) from
103 oak.oakland.edu:/simtel/msdos/pktdrvr. It won't work perfectly on a 386+
104 without patches, though, and also doesn't like several cards.  Fixed
105 versions are available on my WWW page, or via e-mail if you don't have WWW
106 access.
107 
108 
109 Installing the Driver
110 ---------------------
111 
112 All 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 
120 If you obtained this ARCnet package as an upgrade to the ARCnet driver in
121 your current kernel, you will need to first copy arcnet.c over the one in
122 the linux/drivers/net directory.
123 
124 You will know the driver is installed properly if you get some ARCnet
125 messages when you reboot into the new Linux kernel.
126 
127 There are four chipset options:
128 
129  1. Standard ARCnet COM90xx chipset.
130 
131 This is the normal ARCnet card, which you've probably got. This is the only
132 chipset driver which will autoprobe if not told where the card is.
133 It following options on the command line::
134 
135  com90xx=[<io>[,<irq>[,<shmem>]]][,<name>] | <name>
136 
137 If you load the chipset support as a module, the options are::
138 
139  io=<io> irq=<irq> shmem=<shmem> device=<name>
140 
141 To disable the autoprobe, just specify "com90xx=" on the kernel command line.
142 To specify the name alone, but allow autoprobe, just put "com90xx=<name>"
143 
144  2. ARCnet COM20020 chipset.
145 
146 This is the new chipset from SMC with support for promiscuous mode (packet
147 sniffing), extra diagnostic information, etc. Unfortunately, there is no
148 sensible method of autoprobing for these cards. You must specify the I/O
149 address on the kernel command line.
150 
151 The command line options are::
152 
153  com20020=<io>[,<irq>[,<node_ID>[,backplane[,CKP[,timeout]]]]][,name]
154 
155 If 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 
160 The COM20020 chipset allows you to set the node ID in software, overriding the
161 default which is still set in DIP switches on the card. If you don't have the
162 COM20020 data sheets, and you don't know what the other three options refer
163 to, then they won't interest you - forget them.
164 
165  3. ARCnet COM90xx chipset in IO-mapped mode.
166 
167 This will also work with the normal ARCnet cards, but doesn't use the shared
168 memory. It performs less well than the above driver, but is provided in case
169 you have a card which doesn't support shared memory, or (strangely) in case
170 you have so many ARCnet cards in your machine that you run out of shmem slots.
171 If you don't give the IO address on the kernel command line, then the driver
172 will not find the card.
173 
174 The command line options are::
175 
176  com90io=<io>[,<irq>][,<name>]
177 
178 If 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 
183 These are COM90xx chips which are _completely_ memory mapped. The support for
184 these is not tested. If you have one, please mail the author with a success
185 report. All options must be specified, except the device name.
186 Command line options::
187 
188  arcrimi=<shmem>,<irq>,<node_ID>[,<name>]
189 
190 If you load the chipset support as a module, the options are::
191 
192  shmem=<shmem> irq=<irq> node=<node_ID> device=<name>
193 
194 
195 Loadable Module Support
196 -----------------------
197 
198 Configure and rebuild Linux.  When asked, answer 'm' to "Generic ARCnet
199 support" and to support for your ARCnet chipset if you want to use the
200 loadable module. You can also say 'y' to "Generic ARCnet support" and 'm'
201 to the chipset support if you wish.
202 
203 ::
204 
205         make config
206         make clean
207         make zImage
208         make modules
209 
210 If you're using a loadable module, you need to use insmod to load it, and
211 you can specify various characteristics of your card on the command
212 line.  (In recent versions of the driver, autoprobing is much more reliable
213 and works as a module, so most of this is now unnecessary.)
214 
215 For 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 
223 Using the Driver
224 ----------------
225 
226 If you build your kernel with ARCnet COM90xx support included, it should
227 probe for your card automatically when you boot. If you use a different
228 chipset driver complied into the kernel, you must give the necessary options
229 on the kernel command line, as detailed above.
230 
231 Go read the NET-2-HOWTO and ETHERNET-HOWTO for Linux; they should be
232 available where you picked up this driver.  Think of your ARCnet as a
233 souped-up (or down, as the case may be) Ethernet card.
234 
235 By the way, be sure to change all references from "eth0" to "arc0" in the
236 HOWTOs.  Remember that ARCnet isn't a "true" Ethernet, and the device name
237 is DIFFERENT.
238 
239 
240 Multiple Cards in One Computer
241 ------------------------------
242 
243 Linux has pretty good support for this now, but since I've been busy, the
244 ARCnet driver has somewhat suffered in this respect. COM90xx support, if
245 compiled into the kernel, will (try to) autodetect all the installed cards.
246 
247 If you have other cards, with support compiled into the kernel, then you can
248 just repeat the options on the kernel command line, e.g.::
249 
250         LILO: linux com20020=0x2e0 com20020=0x380 com90io=0x260
251 
252 If you have the chipset support built as a loadable module, then you need to
253 do something like this::
254 
255         insmod -o arc0 com90xx
256         insmod -o arc1 com20020 io=0x2e0
257         insmod -o arc2 com90xx
258 
259 The ARCnet drivers will now sort out their names automatically.
260 
261 
262 How do I get it to work with...?
263 --------------------------------
264 
265 NFS:
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 
281 DOS:
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 
288 Windows:
289         See DOS :)  Trumpet Winsock works fine with either the Novell or
290         Arcether client, assuming you remember to load winpkt of course.
291 
292 LAN 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 
305 Windows 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 
314 OS/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 
324 NetBSD/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 
331 Using Multiprotocol ARCnet
332 --------------------------
333 
334 The 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 
374 You can choose not to compile arc0e and arc0s into the driver if you want -
375 this will save you a bit of memory and avoid confusion when eg. trying to
376 use the "NFS-root" stuff in recent Linux kernels.
377 
378 The arc0e and arc0s devices are created automatically when you first
379 ifconfig the arc0 device.  To actually use them, though, you need to also
380 ifconfig the other virtual devices you need.  There are a number of ways you
381 can set up your network then:
382 
383 
384 1. 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 
408 2. 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 
523 It works: what now?
524 -------------------
525 
526 Send mail describing your setup, preferably including driver version, kernel
527 version, ARCnet card model, CPU type, number of systems on your network, and
528 list of software in use to me at the following address:
529 
530         apenwarr@worldvisions.ca
531 
532 I do send (sometimes automated) replies to all messages I receive.  My email
533 can be weird (and also usually gets forwarded all over the place along the
534 way to me), so if you don't get a reply within a reasonable time, please
535 resend.
536 
537 
538 It doesn't work: what now?
539 --------------------------
540 
541 Do the same as above, but also include the output of the ifconfig and route
542 commands, as well as any pertinent log entries (ie. anything that starts
543 with "arcnet:" and has shown up since the last reboot) in your mail.
544 
545 If you want to try fixing it yourself (I strongly recommend that you mail me
546 about the problem first, since it might already have been solved) you may
547 want to try some of the debug levels available.  For heavy testing on
548 D_DURING or more, it would be a REALLY good idea to kill your klogd daemon
549 first!  D_DURING displays 4-5 lines for each packet sent or received.  D_TX,
550 D_RX, and D_SKB actually DISPLAY each packet as it is sent or received,
551 which is obviously quite big.
552 
553 Starting with v2.40 ALPHA, the autoprobe routines have changed
554 significantly.  In particular, they won't tell you why the card was not
555 found unless you turn on the D_INIT_REASONS debugging flag.
556 
557 Once the driver is running, you can run the arcdump shell script (available
558 from me or in the full ARCnet package, if you have it) as root to list the
559 contents of the arcnet buffers at any time.  To make any sense at all out of
560 this, you should grab the pertinent RFCs. (some are listed near the top of
561 arcnet.c).  arcdump assumes your card is at 0xD0000.  If it isn't, edit the
562 script.
563 
564 Buffers 0 and 1 are used for receiving, and Buffers 2 and 3 are for sending.
565 Ping-pong buffers are implemented both ways.
566 
567 If your debug level includes D_DURING and you did NOT define SLOW_XMIT_COPY,
568 the buffers are cleared to a constant value of 0x42 every time the card is
569 reset (which should only happen when you do an ifconfig up, or when Linux
570 decides that the driver is broken).  During a transmit, unused parts of the
571 buffer will be cleared to 0x42 as well.  This is to make it easier to figure
572 out which bytes are being used by a packet.
573 
574 You 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 
579 where "xxx" is the debug level you want.  For example, "metric 1015" would put
580 you at debug level 15.  Debug level 7 is currently the default.
581 
582 Note that the debug level is (starting with v1.90 ALPHA) a binary
583 combination of different debug flags; so debug level 7 is really 1+2+4 or
584 D_NORMAL+D_EXTRA+D_INIT.  To include D_DURING, you would add 16 to this,
585 resulting in debug level 23.
586 
587 If you don't understand that, you probably don't want to know anyway.
588 E-mail me about your problem.
589 
590 
591 I want to send money: what now?
592 -------------------------------
593 
594 Go take a nap or something.  You'll feel better in the morning.

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