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diff --git a/Documentation/networking/arcnet.rst b/Documentation/networking/arcnet.rst new file mode 100644 index 000000000..4e541aa44 --- /dev/null +++ b/Documentation/networking/arcnet.rst @@ -0,0 +1,399 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====== +ARCnet +====== + +:Author: Avery Pennarun <apenwarr@worldvisions.ca> + +.. note:: + + See also arcnet-hardware.rst in this directory for jumper-setting + and cabling information if you're like many of us and didn't happen to get a + manual with your ARCnet card. + +---- + +These are the ARCnet drivers for Linux. + +This new release (2.91) has been put together by David Woodhouse +<dwmw2@infradead.org>, in an attempt to tidy up the driver after adding support +for yet another chipset. Now the generic support has been separated from the +individual chipset drivers, and the source files aren't quite so packed with +#ifdefs! I've changed this file a bit, but kept it in the first person from +Avery, because I didn't want to completely rewrite it. + +The previous release resulted from many months of on-and-off effort from me +(Avery Pennarun), many bug reports/fixes and suggestions from others, and in +particular a lot of input and coding from Tomasz Motylewski. Starting with +ARCnet 2.10 ALPHA, Tomasz's all-new-and-improved RFC1051 support has been +included and seems to be working fine! + + +.. _arcnet-netdev: + +Where do I discuss these drivers? +--------------------------------- + +ARCnet discussions take place on netdev. Simply send your email to +netdev@vger.kernel.org and make sure to Cc: maintainer listed in +"ARCNET NETWORK LAYER" heading of Documentation/process/maintainers.rst. + +Other Drivers and Info +---------------------- + +You can try JoAnne Schmitz's ARCNET page on the World Wide Web at: + + https://www.qis.net/~jschmitz/arcnet/ + + +Supported Hardware +------------------ + +Only PCI and PCI Express devices based on the COM20020 chipset are supported. +This is the newest chipset from SMC with support for promiscuous mode (packet +sniffing), extra diagnostic information, etc. These devices use the com20020_pci +driver. + +Support for older chipsets and ISA and PCMCIA devices was previously available +but has been removed. + + +Configuring the Driver +---------------------- + +The COM20020 driver will be loaded automatically at boot if a supported card is +detected. + +If the com20020_pci driver was compiled as a loadable module, the options are:: + + node=<node_ID> backplane=<backplane> clockp=<CKP> clockm=<CKM> + timeout=<timeout> device=<interface_name> + +If the driver was compiled into the kernel, the same options can be specified on +the kernel command line by prefixing them with `com20020_pci.`, as in the +following example:: + + com20020_pci.device=eth1 + +The COM20020 chipset allows you to set the node ID in software, overriding the +default which is still set in DIP switches on the card. If you don't have the +COM20020 data sheets, and you don't know what the other options refer +to, then they won't interest you - forget them. + +Otherwise, ARCnet can be configured in a similar way to Ethernet, with the +exception that ARCnet interface names begin with `arc`. + + +How do I get it to work with...? +-------------------------------- + +NFS: + Should be fine linux->linux, just pretend you're using Ethernet cards. + oak.oakland.edu:/simtel/msdos/nfs has some nice DOS clients. There + is also a DOS-based NFS server called SOSS. It doesn't multitask + quite the way Linux does (actually, it doesn't multitask AT ALL) but + you never know what you might need. + + With AmiTCP (and possibly others), you may need to set the following + options in your Amiga nfstab: MD 1024 MR 1024 MW 1024 + (Thanks to Christian Gottschling <ferksy@indigo.tng.oche.de> + for this.) + + Probably these refer to maximum NFS data/read/write block sizes. I + don't know why the defaults on the Amiga didn't work; write to me if + you know more. + +DOS: + If you're using the freeware arcether.com, you might want to install + the driver patch from my web page. It helps with PC/TCP, and also + can get arcether to load if it timed out too quickly during + initialization. In fact, if you use it on a 386+ you REALLY need + the patch, really. + +Windows: + See DOS :) Trumpet Winsock works fine with either the Novell or + Arcether client, assuming you remember to load winpkt of course. + +LAN Manager and Windows for Workgroups: + These programs use protocols that + are incompatible with the Internet standard. They try to pretend + the cards are Ethernet, and confuse everyone else on the network. + + The Linux ARCnet driver supports this protocol via the 'arc0e' device. + See the section on "Multiprotocol Support" for more information. + + Using the freeware Samba server and clients for Linux, you can now + interface quite nicely with TCP/IP-based WfWg or Lan Manager + networks. + +Windows 95: + Tools are included with Win95 that let you use either the LANMAN + style network drivers (NDIS) or Novell drivers (ODI) to handle your + ARCnet packets. If you use ODI, you'll need to use the 'arc0' + device with Linux. If you use NDIS, then try the 'arc0e' device. + See the "Multiprotocol Support" section below if you need arc0e, + you're completely insane, and/or you need to build some kind of + hybrid network that uses both encapsulation types. + +OS/2: + I've been told it works under Warp Connect with an ARCnet driver from + SMC. You need to use the 'arc0e' interface for this. If you get + the SMC driver to work with the TCP/IP stuff included in the + "normal" Warp Bonus Pack, let me know. + + ftp.microsoft.com also has a freeware "Lan Manager for OS/2" client + which should use the same protocol as WfWg does. I had no luck + installing it under Warp, however. Please mail me with any results. + +NetBSD/AmiTCP: + These use an old version of the Internet standard ARCnet + protocol (RFC1051) which is compatible with the Linux driver v2.10 + ALPHA and above using the arc0s device. (See "Multiprotocol ARCnet" + below.) ** Newer versions of NetBSD apparently support RFC1201. + + +Using Multiprotocol ARCnet +-------------------------- + +The ARCnet driver supports three protocols, each on its own +"virtual network device": + + ====== =============================================================== + arc0 RFC1201 protocol, the official Internet standard which just + happens to be 100% compatible with Novell's TRXNET driver. + Version 1.00 of the ARCnet driver supported _only_ this + protocol. arc0 is the fastest of the three protocols (for + whatever reason), and allows larger packets to be used + because it supports RFC1201 "packet splitting" operations. + Unless you have a specific need to use a different protocol, + I strongly suggest that you stick with this one. + + arc0e "Ethernet-Encapsulation" which sends packets over ARCnet + that are actually a lot like Ethernet packets, including the + 6-byte hardware addresses. This protocol is compatible with + Microsoft's NDIS ARCnet driver, like the one in WfWg and + LANMAN. Because the MTU of 493 is actually smaller than the + one "required" by TCP/IP (576), there is a chance that some + network operations will not function properly. The Linux + TCP/IP layer can compensate in most cases, however, by + automatically fragmenting the TCP/IP packets to make them + fit. arc0e also works slightly more slowly than arc0, for + reasons yet to be determined. (Probably it's the smaller + MTU that does it.) + + arc0s The "[s]imple" RFC1051 protocol is the "previous" Internet + standard that is completely incompatible with the new + standard. Some software today, however, continues to + support the old standard (and only the old standard) + including NetBSD and AmiTCP. RFC1051 also does not support + RFC1201's packet splitting, and the MTU of 507 is still + smaller than the Internet "requirement," so it's quite + possible that you may run into problems. It's also slower + than RFC1201 by about 25%, for the same reason as arc0e. + + The arc0s support was contributed by Tomasz Motylewski + and modified somewhat by me. Bugs are probably my fault. + ====== =============================================================== + +You can choose not to compile arc0e and arc0s into the driver if you want - +this will save you a bit of memory and avoid confusion when eg. trying to +use the "NFS-root" stuff in recent Linux kernels. + +The arc0e and arc0s devices are created automatically when you first +ifconfig the arc0 device. To actually use them, though, you need to also +ifconfig the other virtual devices you need. There are a number of ways you +can set up your network then: + + +1. Single Protocol. + + This is the simplest way to configure your network: use just one of the + two available protocols. As mentioned above, it's a good idea to use + only arc0 unless you have a good reason (like some other software, ie. + WfWg, that only works with arc0e). + + If you need only arc0, then the following commands should get you going:: + + ifconfig arc0 MY.IP.ADD.RESS + route add MY.IP.ADD.RESS arc0 + route add -net SUB.NET.ADD.RESS arc0 + [add other local routes here] + + If you need arc0e (and only arc0e), it's a little different:: + + ifconfig arc0 MY.IP.ADD.RESS + ifconfig arc0e MY.IP.ADD.RESS + route add MY.IP.ADD.RESS arc0e + route add -net SUB.NET.ADD.RESS arc0e + + arc0s works much the same way as arc0e. + + +2. More than one protocol on the same wire. + + Now things start getting confusing. To even try it, you may need to be + partly crazy. Here's what *I* did. :) Note that I don't include arc0s in + my home network; I don't have any NetBSD or AmiTCP computers, so I only + use arc0s during limited testing. + + I have three computers on my home network; two Linux boxes (which prefer + RFC1201 protocol, for reasons listed above), and one XT that can't run + Linux but runs the free Microsoft LANMAN Client instead. + + Worse, one of the Linux computers (freedom) also has a modem and acts as + a router to my Internet provider. The other Linux box (insight) also has + its own IP address and needs to use freedom as its default gateway. The + XT (patience), however, does not have its own Internet IP address and so + I assigned it one on a "private subnet" (as defined by RFC1597). + + To start with, take a simple network with just insight and freedom. + Insight needs to: + + - talk to freedom via RFC1201 (arc0) protocol, because I like it + more and it's faster. + - use freedom as its Internet gateway. + + That's pretty easy to do. Set up insight like this:: + + ifconfig arc0 insight + route add insight arc0 + route add freedom arc0 /* I would use the subnet here (like I said + to in "single protocol" above), + but the rest of the subnet + unfortunately lies across the PPP + link on freedom, which confuses + things. */ + route add default gw freedom + + And freedom gets configured like so:: + + ifconfig arc0 freedom + route add freedom arc0 + route add insight arc0 + /* and default gateway is configured by pppd */ + + Great, now insight talks to freedom directly on arc0, and sends packets + to the Internet through freedom. If you didn't know how to do the above, + you should probably stop reading this section now because it only gets + worse. + + Now, how do I add patience into the network? It will be using LANMAN + Client, which means I need the arc0e device. It needs to be able to talk + to both insight and freedom, and also use freedom as a gateway to the + Internet. (Recall that patience has a "private IP address" which won't + work on the Internet; that's okay, I configured Linux IP masquerading on + freedom for this subnet). + + So patience (necessarily; I don't have another IP number from my + provider) has an IP address on a different subnet than freedom and + insight, but needs to use freedom as an Internet gateway. Worse, most + DOS networking programs, including LANMAN, have braindead networking + schemes that rely completely on the netmask and a 'default gateway' to + determine how to route packets. This means that to get to freedom or + insight, patience WILL send through its default gateway, regardless of + the fact that both freedom and insight (courtesy of the arc0e device) + could understand a direct transmission. + + I compensate by giving freedom an extra IP address - aliased 'gatekeeper' - + that is on my private subnet, the same subnet that patience is on. I + then define gatekeeper to be the default gateway for patience. + + To configure freedom (in addition to the commands above):: + + ifconfig arc0e gatekeeper + route add gatekeeper arc0e + route add patience arc0e + + This way, freedom will send all packets for patience through arc0e, + giving its IP address as gatekeeper (on the private subnet). When it + talks to insight or the Internet, it will use its "freedom" Internet IP + address. + + You will notice that we haven't configured the arc0e device on insight. + This would work, but is not really necessary, and would require me to + assign insight another special IP number from my private subnet. Since + both insight and patience are using freedom as their default gateway, the + two can already talk to each other. + + It's quite fortunate that I set things up like this the first time (cough + cough) because it's really handy when I boot insight into DOS. There, it + runs the Novell ODI protocol stack, which only works with RFC1201 ARCnet. + In this mode it would be impossible for insight to communicate directly + with patience, since the Novell stack is incompatible with Microsoft's + Ethernet-Encap. Without changing any settings on freedom or patience, I + simply set freedom as the default gateway for insight (now in DOS, + remember) and all the forwarding happens "automagically" between the two + hosts that would normally not be able to communicate at all. + + For those who like diagrams, I have created two "virtual subnets" on the + same physical ARCnet wire. You can picture it like this:: + + + [RFC1201 NETWORK] [ETHER-ENCAP NETWORK] + (registered Internet subnet) (RFC1597 private subnet) + + (IP Masquerade) + /---------------\ * /---------------\ + | | * | | + | +-Freedom-*-Gatekeeper-+ | + | | | * | | + \-------+-------/ | * \-------+-------/ + | | | + Insight | Patience + (Internet) + + + +It works: what now? +------------------- + +:ref:`Send an email to netdev <arcnet-netdev>`. Describe your setup, preferably +including driver version, kernel version, ARCnet card model, CPU type, number +of systems on your network, and list of software in use. + +It doesn't work: what now? +-------------------------- + +Do the same as above, but also include the output of the ifconfig and route +commands, as well as any pertinent log entries (ie. anything that starts +with "arcnet:" and has shown up since the last reboot) in your mail. + +If you want to try fixing it yourself (I strongly recommend that you mail me +about the problem first, since it might already have been solved) you may +want to try some of the debug levels available. For heavy testing on +D_DURING or more, it would be a REALLY good idea to kill your klogd daemon +first! D_DURING displays 4-5 lines for each packet sent or received. D_TX, +D_RX, and D_SKB actually DISPLAY each packet as it is sent or received, +which is obviously quite big. + +Once the driver is running, you can run the arcdump shell script (available +from me or in the full ARCnet package, if you have it) as root to list the +contents of the arcnet buffers at any time. To make any sense at all out of +this, you should grab the pertinent RFCs. (some are listed near the top of +arcnet.c). arcdump assumes your card is at 0xD0000. If it isn't, edit the +script. + +Buffers 0 and 1 are used for receiving, and Buffers 2 and 3 are for sending. +Ping-pong buffers are implemented both ways. + +If your debug level includes D_DURING and you did NOT define SLOW_XMIT_COPY, +the buffers are cleared to a constant value of 0x42 every time the card is +reset (which should only happen when you do an ifconfig up, or when Linux +decides that the driver is broken). During a transmit, unused parts of the +buffer will be cleared to 0x42 as well. This is to make it easier to figure +out which bytes are being used by a packet. + +You can change the debug level without recompiling the kernel by typing:: + + ifconfig arc0 down metric 1xxx + ifconfig arc0 up + +where "xxx" is the debug level you want. For example, "metric 1015" would put +you at debug level 15. Debug level 7 is currently the default. + +Note that the debug level is a binary combination of different debug flags; +debug level 7 is really 1+2+4 or D_NORMAL+D_EXTRA+D_INIT. To include D_DURING, +you would add 16 to this, resulting in debug level 23. + +If you don't understand that, you probably don't want to know anyway. |