From: Paul Gortmaker Newsgroups: comp.os.linux.announce,comp.os.linux.admin,comp.answers,news.answers Subject: Linux Ethernet HOWTO (Part 1/2) Keywords: Linux, Ethernet, TCP/IP, NET-2 Followup-To: poster Approved: linux-announce@tc.cornell.edu (Matt Welsh) Archive-Name: linux/howto/ethernet/part1 Last-Modified: November 16, 1993 Linux Ethernet HOWTO v0.3 -- Last updated November 6, 1993 ================================================================= INDEX: (Part 1/2) 0 Introduction. 0.01 How do I use this Guide? 0.01 Disclaimer 0.02 Questions already? 0.03 Related Documentation 0.04 New Versions of this Document 0.05 Feedback 1 What card should I buy for Linux? 1.01 Eight bit vs 16 bit 1.02 Low price Ethernet cards 1.03 Vendors and brands to avoid. 1.04 Type of cable that your card should support 2 Status of various Ethernet cards under Linux. 2.01 3Com 2.02 Western Digital / SMC 2.03 NExxxx 2.04 Hewlett Packard Cards 2.05 D-Link 2.06 Cabletron 2.07 Allied Telesis 2.08 Arcnet 2.09 Digital / DEC 2.10 Intel 2.11 PureData 2.12 Xircom 2.13 Zenith 2.14 Racal-Interlan 2.15 AMD LANCE (79C960) 2.16 AT-Lan-Tec 3 Clones of popular Ethernet cards. 3.01 WD80x3 Clones 3.02 NE2000 Clones 4 Cables, coax, twisted pairs etc. 4.01 Thin Ethernet (thinnet) 4.02 Twisted Pair 4.03 Thick Ethernet (Part 2/2) 5 Technical information. 5.01 Probed addresses 5.02 Skeleton / prototype driver 5.03 Driver interface to the kernel 5.04 Interrupts and linux 5.05 Programmed I/O vs. shared mem. vs slave/master DMA 5.06 Programming the Intel chips (i82586 and i82593) 5.07 Programming information from 3Com 5.08 Notes on AMD PCnet-ISA / LANCE Based cards (79C960) 5.09 Multicast and Promiscuous mode 5.10 The Berkely Packet Filter (BPF) 5.11 Unresolved questions / concerns 6 Possible problems, questions and troubleshooting. 6.01 Problems with NE2000 (and clones) 6.02 Problems with WD80*3 cards 6.03 Problems with 3Com cards 7 Networking with a laptop computer. 7.01 Option 1 -- using SLIP 7.02 Option 2 -- Built in NE2000 compatible or PCMCIA Ethercard. 7.03 Option 3 -- ISA Ethercard in the docking station. 7.04 Option 4 -- Pocket / parallel port adaptors. 8 Frequently asked questions. 8.01 Just the FAQ's ma'am -- just the FAQ's. 9 Miscellaneous. 9.01 The Cabletron story. 9.02 The Xircom story 9.03 Closing ====================================================================== 0. Introduction. This is the Ethernet-HOWTO, which is a compilation of information about which ethernet devices can be used for Linux, and how to set them up. This Ethernet-HOWTO is by: Donald J. Becker Paul Gortmaker It covers what cards you should and shouldn't buy; how to set them up, how to run more than one, and other common problems and questions. It does *not* cover the software end of things, as that is covered in the NET-2 HOWTO. You can freely distribute this document as long as you distribute an original copy with the author's names intact. Other people who have contributed (directly or indirectly) are, in alphabetical order: Peter Bauer Ross Biro Alan Cox Bjorn Ekwall Mike Jagdis Duke Kamstra Russell Nelson Cameron Spitzer Dave Roberts Glenn Talbott Miquel van Smoorenburg Many thanks to the above people, and all the other unmentioned testers out there. 0.01 How Do I Use This Guide? As this guide is getting bigger and bigger, you probably don't want to spend the rest of your afternoon reading the whole thing. And you don't *have* to read it all. If you haven't got an ethernet card, then you will want to start with section one to see what you should buy, and what you should avoid. If you have already got an ethernet card, but are not sure if you can use it with Linux, then you will want to read section two, which contains specific information on each manufacturer, and their cards. If you are having trouble with your card, then you will want to read the specific information about your card in section two and the troubleshooting information in section six. If you are intersted in some of the technical aspects of the device drivers, then you can find that information in section 5. 0.01 Disclaimer This document is *not* gospel. However, it is probably the most up to date info that you will be able to find. Nobody is responsible for what happens to your hardware but yourself. If your ethercard or any other hardware goes up in smoke (...nearly impossible!) we take no responsibility. ie. THE AUTHORS ARE NOT RESPONSIBLE FOR ANY DAMAGES INCURRED DUE TO ACTIONS TAKEN BASED ON THE INFORMATION INCLUDED IN THIS DOCUMENT. 0.02 Questions already? If you have questions about your ethernet card, please READ this document first. You may also want to join the NET channel of the Linux-activists mailing list by sending mail to linux-activists-request@niksula.hut.fi with the line X-Mn-Admin: join NET at the top of the message body (not the subject). If you want to learn how to use the mailing channels, then send an empty message to the above address, and you will get an instruction manual sent back to you in a few hours. However, it is worth noting that the NET channel is primarily used for discussion of the networking code, and you may not see much discussion about a particular driver. Furthermore keep in mind that the NET channel is for development discussions only. General questions on how to configure your system should be directed to comp.os.linux.help unless you are actively involved in the development of part of the networking for Linux. We ask that you *please* respect this general guideline for content. You can safely bet that neither of the authors will respond to any plea for help that *should* be posted to c.o.l.help, but is inappropraitely placed elsewhere. 0.03 Related Documentation Much of this info came from saved postings from the comp.os.linux groups, which shows that it is a valuable resource of information. Other useful information came from a bunch of small files by Donald himself. Some of these are found at /pub/linux/info on ftp.super.org [192.31.192.1] Of course, if you are setting up an Ethernet card, then you will want to read the NET-2 HOWTO so that you can actually do something with it. This is also the home of any alpha drivers that are not presently in the kernel. And last but not least, the contributions from the individuals and companies listed above are greatly appreciated as well. 0.04 New versions of this document New versions of this document can be retrieved via anonymous FTP from sunsite.unc.edu:/pub/Linux/docs/HOWTO/* and various Linux ftp mirror sites. It will also be posted to the newsgroup comp.os.linux.announce at a regular interval. Updates will be made as new information / drivers becomes available. 0.05 Feedback Any corrections can be sent to one of us (gpg109@rsphysse.anu.edu.au or becker@super.org) We will *attempt* to keep this up to date as more drivers become available, and as NET-2 matures. 1 What card should I buy for Linux? For impatient users that just want a quick, cheap answer the summary is: get 16 bit thinnet 8013 cards. For more detail as to the who what where and why, read on. 1.01 Eight bit vs 16 bit Unless you are a light user, or are confined to using the smaller ISA slot, the use of the 8 bit cards like the wd8003 and the 3c503 is really not worth the cost savings. Get the 8013 or the 3c503/16 instead. 1.02 Low price Ethernet cards I keep track of the current low-price vendors, just because it's asked so often. Call AT-LAN-TEC at 301-948-7070. Ask for their technical support person, "Vincent Bono". As with all purchases, you should indicate you are buying this for a Linux system. The last I checked the price for 10 NE2000s was $480, or $48 ea.! NB: Their current NE2000 clone is a model that "traps" other drivers that probe into their address space. AT-LAN-TEC also carries a clone, non-EEPROM 8013 board for somewhat more, and a NE2100 clone. Either is a better choice if the very lowest price isn't essential. The Allied Telesis AT1500 is offered at a good price by many vendors. Even Inmac, known for their premium markup, has this card for under $100. 1.03 Vendors and Brands to Avoid These vendors have decided *not* to release programming information about their products, without signing a non-disclosure agreement. More information can be found in sections two and nine. Hence there is no support for products offered from these companies: (1) Cabletron (2) Xircom These particular cards should be avoided, as they are obsolete. The reasons as to why they have been classified as such can be found in section 2 of this document. (1) 3c501 (2) Arcnet 1.04 Type of cable that your card should support Unless you have to conform to an existing network, you will want to use thinnet or thin ethernet cable. This is the style with the standard BNC connectors. See section 4 for other concerns with different types of ethernet cable. Most ethercards also come in a "Combo" version for only $10-$20 more. These have both twisted pair and thinnet transceiver built-in, allowing you to change your mind later. 2 Status of Various Ethernet Cards under Linux The only thing that one needs to use an ethernet card with Linux is the appropriate driver. For this, it is essential that the manufacturer will release the technical programming information to the general public without you (or anyone) having to sign your life away. A good guide for the likelihood of getting documentation (or, if you aren't writing code, the likelihood that someone else will write that driver you really, really need) is the availability of the Crynwr (nee Clarkson) packet driver. Russ Nelson (see the acknowledgements in the intro.) runs this operation, and has been very helpful in supporting the development of drivers for Linux. Given the documentation, you can write a driver for your card and use it for Linux, at least in theory. Keep in mind that some old hardware that was designed for XT type machines will not function very well in a multitasking environment such as Linux. Use of these will lead to major problems if your network sees a reasonable amount of traffic. Most cards come with drivers for MS-DOS interfaces such as NDIS and ODI, but these are useless for Linux. Many people have suggested directly linking them in or automatic translation, but this is nearly impossible. The MS-DOS drivers expect to be in 16 bit mode and hook into "software interrupts", both incompatible with the Linux kernel. This incompatibility is actually a feature, as some Linux drivers are considerably better than their MS-DOS counterparts. The "8390" series drivers, for instance, use ping-pong transmit buffers, which are only now being introduced in the MS-DOS world. Keep in mind that PC ethercards have the widest variety of interfaces (shared memory, programmed I/O, bus-master, or slave DMA) of any computer hardware for anything, and supporting a new ethercard sometimes requires re-thinking most of the lower-level networking code. (If you are interested in learning more about these different forms of interfaces, see section 5) Also, similar product numbers don't always indicate similar products. For instance, the 3c50* product line from 3Com varies wildly between different members. Enough talk. Let's get down to the information you want. 2.01 3Com Supported: 3c503, 3c503/16 3Com shared-memory ethercards. They also have a programmed I/O mode that doesn't use the 8390 facilities (their engineers found too many bugs!) It should be about the same speed as the same bus width WD80x3, but I don't have a 16 bit version to benchmark. Unless you are a light user, spend the extra money and get the 16 bit model, as the price difference isn't significant. The 3c503 does not have "EEPROM setup", so the diagnostic/setup program isn't needed before running the card with Linux. The shared memory address of the 3c503 is set using jumpers that are shared with the boot PROM address. This is confusing to people familiar with other ISA cards, where you always leave the jumper set to "disable" unless you have a boot PROM. The Linux 3c503 driver can also work with the 3c503 programmed-I/O mode, but this is slower and less reliable than shared memory mode. Also, programmed-I/O mode is not tested when updating the drivers, the deadman (deadcard?) check code may falsely timeout on some machines, and the probe for a 3c503 in programmed-I/O mode is turned off by default in some versions of the kernel. This was a panic reaction to the general device driver probe explosion; the 3c503 shared memory probe is a safe read from memory, rather than an extensive scan through I/O space. As of pl13, the kernel has a I/O port registrar that makes I/O space probes safer, (see section 5.1 for more info.) and the programmed-I/O 3c503 probe has been re-enabled. You still shouldn't use the programmed-I/O mode though, unless you need it for MS-DOS compatibility. The 3c503's IRQ line is set in software, with no hints from an EEPROM. Unlike the MS-DOS drivers, the Linux driver has capability to autoIRQ: it uses the first available IRQ line in {5,2/9,3,4}, selected each time the card is 'ifconfig'ed. (Older driver versions selected the IRQ at boot time.) The ioctl() call in 'ifconfig' will return EAGAIN if no IRQ line is available at that time. The 0.99pl13 open-time-autoIRQ 3c503 driver has two minor bugs. The first is that autoIRQ list is effect- ively {5, 3, 4} instead of {5, 2/9, 3, 4}. The second is that if you use autoIRQ the interrupt channel isn't set the first time, and the board is frozen until the first transmit timeout triggers a board reset. After that, everything works fine. The fixed version will be in pl14 if alpha-tester reports are received in time. 3c509 A new card from 3Com. It's inexpensive and has excellent performance for a non-bus-master design. The drawbacks are that it _requires_ very low interrupt latency, and it isn't rated for bus speeds greater than 8Mhz. A working 3c509 driver is included as an alpha-test version in the 0.99pl13 kernel sources, but it's not enabled by default. You'll have to edit config.in by hand to remove the comment character in front of the 3c509 line. The 3c509 has a tiny Rx buffer, causing the driver to occasionally drop a packet if interrupts are masked for too long. To minimize this problem, the driver should be completely rewritten to use predictive interrupts. (Note: performance re-writes of working drivers are low priority unless there is some particular incentive or need.) It's likely that the EISA 3c579 probe will be working and tested before a new driver is done, so watch for an interim release. There is also an alpha version of a Linux 3c509 diagnostic and EEPROM setup program, but for now users that don't like the defaults should use the MS-DOS EEPROM setup program. 3c579 The EISA version of the 509. The current EISA version uses the same 16 bit wide chip rather than a 32 bit interface, so the performance increase isn't stunning. The 3c509 driver should work with the EISA version, if the EISA version is configured to an ISA base address. (I have neither an EISA machine nor a 3c579 to test it on. -djb) We would be interested in hearing progress reports from any 3c579 users. (Read the above 3c509 section for info on the driver.) Cameron Spitzer writes: "The 3C579 (Etherlink III EISA) should be configured as an EISA card. The IO Base Address (window 0 register 6 bits 4:0) should be 1f, which selects EISA addressing mode. Logic outside the ASIC decodes the IO address s000, where s is the slot number. I don't think it was documented real well. Except for its IO Base Address, the '579 should behave EXACTLY like the '509 (EL3 ISA), and if it doesn't, I want to hear about it (at my work address). I will leave it to the Real Programmers to suggest the right hack to /usr/src/linux/net/inet/3c509.c to take care of the EISA case. Beware that if you put a '509 in EISA addressing mode by mistake and save that in the EEPROM, you'll have to use an EISA machine or the infamous Test Via to get it back to normal, and it will conflict at IO location 0 which may hang your ISA machine. It's not my job to say whether this is a bug or feature, but I have heard loud and clear that customers don't like it and I don't think we'll do it that way again." Unsupported: 3c501 Too brain-damaged to use. Available surplus from many places. Avoid it like the plague. Again, do not purchase this card, even as a joke. It's performance is horrible, and it breaks in many ways. (I have a standing offer: I'll pay $2 for each 3c501 shipped to me postpaid, but only if you include the BNC 'T' connector and the jumpers. $2.50 if you just send the 'T', jumpers, and address PROM and promise to destroy the board. -djb) Cameron L. Spitzer of 3Com said: "I'm speaking only for myself here, of course, but I believe 3Com advises against installing a 3C501 in a new system, mostly for the same reasons Donald has discussed. You probably won't be happy with the 3C501 in your Linux box. The data sheet is marked "(obsolete)" on 3Com's Developers' Order Form, and the board is not part of 3Com's program for sending free Technical Reference Manuals to people who need them. The decade-old things are nearly indestructible, but that's about all they've got going for them any more." For those not yet convinced, the 3c501 can only do one thing at a time -- while you are removing one packet from the single-packet buffer it cannot receive another packet, nor can it receive a packet while are loading a transmit packet. This was fine for a network between two 8088-based computers where processing each packet and replying took 10's of msecs, but modern networks send back-to-back packets for almost every transaction. Having read this far, you must be persistent, so you get let in on a secret. As of pl13, some more of the hardware problems were "compensated for". Ie. in a fit of madness I wasted a whole day updating my 3c501 driver and then trying to track down a few more of the 3c501 glitches. It now works well enough to NFS mount filesystems, but the receiver still occasionally hangs. I'm mostly certain that this is a hardware bug. When it hangs, the next set of outgoing packets will reset the board, but that's only useful if you have something occasionally generating outgoing packets. I'll let this out for "pre-alpha" testing, under the following conditions: This is unsupported code. I know my usual copyright says all the code is unsupported, but this is _really_ unsupported. I DON'T want to see bug reports, and I'll accept bug fixes only if I'm in a good mood that day. I don't want to see a fest of "Linux ethercards for sale" postings. A bunch of people have bought dozens of "dumpster special" 3c501s, and they hope to sell them at rip-off prices. A 3c501 is barely worth the shipping cost, and if I see people trying to sell them here by claiming "supported by Linux" I _will_ flame them. They are _not_ supported by Linux. I don't want to be flamed later for putting out bad software. I don't know all all of the 3c501 bugs, and I know this driver only handles a few that I've been able to figure out. It has taken a long intense effort just to get the driver working this well. That said, ftp.super.org:/pub/linux/pl14/3c501.c Jumper your card to 0x280, add the 3c501.o to the OBJS line in net/inet/Makefile, uncomment the 3c501 line in linux/config.in, 'make config; make' as usual. AutoIRQ works, DMA isn't used, the autoprobe only looks at 0x280, the debug level is set with the third boot-time argument. You'll probably want to change the default EL_DEBUG to '2'. Once again, THE USE OF A 3c501 IS STRONGLY DISCOURAGED and it is NOT SUPPORTED BY LINUX. 3c505 An Intel-based ethercard with no driver available at present. (Not a very common card.) 3c507 This card uses one of the Intel chips, and the development of the driver is closely related to the development of the Intel Ether Express driver. An alpha driver is presently available. Expect to see the driver in the standard release of pl15. Technical information is available in section 5.06, and if you have experience in writing drivers, see section 5.07 as well. 2.02 Western Digital / SMC The ethernet part of Western Digital has been bought by SMC. The SMC Elite and SMC Elite Plus are the same as late-model WD8003 and WD8013 cards. Note that the SMC Elite Ultra is *not* the same as the plain SMC Elite / WD8013 card. (see below) Supported: WD8003, WD8013, SMC Elite, SMC Elite Plus A shared memory design by Western Digital. The 8 bit 8003 is slightly less expensive, but only worth the savings for light use. Over the years the design has added more registers and an EEPROM. Clones usually go by the '8013' name, and usually use a non-EEPROM (jumpered) design. This part of WD has been sold to SMC, so you'll usually see something like SMC/WD8013 or SMC Elite Plus (WD8013). The shared memory makes the cards 10-20% faster, especially with larger packets. More importantly (to me at least) it avoids a few bugs in the programmed-I/O mode of the 8390, allows safe multi-threaded access to the packet buffer, and doesn't have a programmed-I/O data register that hangs your machine during warm-boot probes. SMC Elite 16 ULTRA This ethercard is based on a new chip from SMC, with a few new features. While it has a mode that is similar to the older SMC ethercards, it's not compatible with the old WD80*3 drivers. However, in this mode it shares most of its code with the other 8390 drivers, while operating somewhat faster than a WD8013 clone. I'm considering writing a separate driver for the Ultra's "Altego" mode which allows chaining transmits at the cost of inefficient use of receive buffers, but that will probably not happen right away. Performance re-writes of working drivers are low priority unless there is some particular incentive or need. This is a new driver, made possible by documentation and ethercard loan from kamstra@ccmail.west.smc.com, Duke Kamstra. If you plan on using an Ultra with Linux send him a note of thanks to let him know that there are Linux users out there! If you would like to _ALPHA_ test this driver: ftp.super.org:/pub/linux/pl14/smc-ultra.c ftp.super.org:/pub/linux/pl14/Space.c You'll have to add an "Ultra" line to config.in and edit net/inet/Makefile. The Ultra driver will probably be (silently?) included in pl14. 2.03 NExxxx The prefix "NE" came from Novell Ethernet. Novell followed the cheapest NatSemi databook design and sold the manufacturing rights (spun off?) Eagle, just to get reasonably-priced ethercards into the market. Supported: NE1000, NE2000 The now-generic name for a bare-bones design around the NatSemi 8390. They use programmed I/O rather than shared memory, leading to easier installation but slightly lower performance and a few problems. Again, the savings of using an 8 bit NE1000 over the NE2000 are only warranted if you expect light use. Some recently introduced NE2000 clones use the National Semiconductor "AT/LANTic" 83905 chip, which offers a shared memory mode similar to the 8013 and EEPROM or software configuration. Some problems can arise with poor clones. See the question and answer section later in this document, and the section on clones. I have written a NE2000 diagnostic program, but it is still presently in alpha test. (ne2k) NE1500, NE2100 The AT1500 driver, recently added to the list of supported cards, also supports the NE1500, NE2100 and clones. The driver shipped with pl12 kernel doesn't detect non-AT1500 cards with autoprobe, but will work fine if you specify the base address explicitly and jumper for DMA channel 5. Read the Allied Telesis section for more information on LANCE based cards. 2.04 Hewlett Packard The 272** cards use programmed I/O, similar to the NE*000 boards, but the data transfer port can be "turned off" when you aren't accessing it, avoiding problems with autoprobing drivers. Thanks to Glenn Talbott for cleaning up the confusion in this section regarding the version numbers of the HP hardware, and adding lots of new info. Supported: 27245A 8 Bit 8390 based 10BaseT, not recommended for all the 8 bit reasons. It was re-designed a couple years ago to be highly integrated which caused some changes in initialization timing which only affected testing programs, not LAN drivers. (The new card is not 'ready' as soon after switching into and out of loopback mode.) 27247B, 27252A The 47B is a 16 Bit 8390 based 10BaseT w/AUI, and the 52A is a 16 Bit 8390 based ThinLAN w/AUI. These cards are high performers (3c509 speed) without the interrupt latency problems (32K onboard RAM for TX or RX packet buffering). They both offer LAN connector autosense, data I/O in I/O space (simpler) or memory mapped (faster), and soft configuration. 27247B was rated Best for ISA Servers by PC Mag this year. 27247A This is the older model that existed before the "B". Two versions 27247-60001 or 27247-60002 have part numbers marked on the card. Functionally the same to the LAN driver, except bits in ROM to identify boards differ. -60002 has a jumper to allow operation in non-standard ISA busses (chipsets that expect IOCHRDY early.) HP J2405A These are lower priced, and slightly faster than the 27247B/27252A, but are missing some features, such as AUI, ThinLAN connectivity, and boot PROM socket. This is a fairly generic LANCE design, but a minor design decision makes it incompatible with a generic "NE2100" driver. Special support for it (including reading the DMA channel from the board) should be in pl14 thanks to information provided by HP's Glenn Talbott, gt@hprnd.rose.hp.com. To use the pl12 and pl13 LANCE driver you must remove the outw(...RESET) calls that are commented "for old NE2100 designs", as these will change the board's base address(!). More information on LANCE based cards can be found in section 5.08. 2.05 D-Link Supported: DE-600 Laptop users and other folk who might want a quick way to put their computer onto the ethernet may want to use this. The driver is included with the default kernel source tree as of pl12 and possibly earlier. Bjorn Ekwall wrote the original. Expect about 80kb/s transfer speed from this via the parallel port. You should read the README.DLINK file in the kernel source tree. The latest release of this driver is v0.32, and it should be included in pl14 if all goes well. DE100, DE200, DE-220-T The manual says that it is 100% compatible with the NE2000. This is not true. You should call them and tell them you are using their card with Linux, and they should correct their documentation. Some pre-0.99pl12 driver versions may have trouble recognizing the DE2** series as 16 bit cards, and these cards are the most widely reported as having the spurious transfer address mismatch errors. Unsupported: DE-620 Same as the DE-600, only with two output formats. Bjorn writes: "I have still no information on the DE-620 that I can include in this release. (Maybe someone well connected to D-Link sees this, hint, hint, hint...) 2.06 Cabletron Yes, another one of these companies that won't release its programming information. They waited for months before actually confirming that all their information was proprietary. If you feel like asking them why they don't want to release their info so that people can use their cards, write to pkelly@ctron.com. You should read section 9.1 of this document, as it has specific information pertaining to Cabletron. Supported: (...well, not *really* supported) E10**, E10**-x, E20**, E20**-x These are NEx000 almost-clones that are reported to work with the standard NEx000 drivers, thanks to a ctron-specific check during the probe. If there are any problems, they are unlikely to be fixed, as the programming information is unavailable. Unsupported: E21** Again, there is not much one can do when the programming information is proprietary. Feel free to ask pkelly@ctron.com. This is the only 8390-based ethercard series that isn't supported by Linux. 2.07 Allied Telesis Allied Telesis is the worlds largest maker of separate transceivers thanks to their low prices, and they now have a series of low-cost ethercards using the 79C960 version of the AMD LANCE. These are bus-master cards, and thus probably the fastest ISA bus ethercards available (although the 3c509 has lower latency thanks to predictive interrupts). Supported: AT1500 The driver for the AT1500 series is new in the 0.99pl12 kernel, but it won't work "out-of-the-box" with >16M machines. (NB This isn't a fundamental limitation, so stop pointing and laughing at the ISA bus. The driver just needs a hook to allocate low-memory buffers for the bus-master DMA, and should be just as fast on >16M systems. It can be easily fixed by initializing the LANCE driver with the character devices, but this fix depends on the resolution of the networking code uncertainty.) For those inquiring about using bus-master LANCE boards with >16M systems, I've been working on that recently. I borrowed 16M from another system here at work, and am using the resulting 32M system while typing this message. The bad news is that the modified driver uses a very ugly interface, and I'm unlikely to have it cleaned up and tested in time for pl14. This driver should also work with NE1500 and NE2100 clones. The pl12 version, included with SLS1.03, is named "le0" rather than "eth0" and it requires the base address to be specified if you don't have a real AT1500. You might be able to use it as easily as using the boot line: lilo: linux ether=0,0x320,le0 (change 0x320 to your true base address) and then changing "eth0" to "le0" in /etc/rc.net. Your DMA channel must be set at DMA5, but autoIRQ does work. The 0.99pl13 driver should be able to autoprobe for your ethercard at the locations {0x300, 0x320, 0x340, 0x360}. Also, the driver is now named "eth0" by default. Future driver versions may figure out a way to autoDMA. Although there is no autoDMA (until I verify that autoDMA is safe and reliable), some versions (pl13) allow passing the DMA channel at boot-time via LILO. (Boot-time parameters can be made permanent in LILO v13+, read the docs.) The DMA channel otherwise defaults to DMA5. Please report the exact chip used by your ethercard, and any success or failure you have. This driver is still young, and I've gotten few reports. More information on AMD LANCE based Ethernet cards can be found in section 5.08. AT1700 The Allied Telesis AT1700 series ethercards are based on the Fujitsu MB86965. This chip uses a programmed I/O interface, and a pair of fixed-size tranmit buffers. This allows small groups of packets to sent be sent back-to-back, with a short pause while switching buffers. A unique feature is the ability to drive 150ohm STP (Shielded Twisted Pair) cable commonly installed for Token Ring, in addition to 10baseT 100ohm UTP (unshielded twisted pair). A mis-feature to watch out for is that the current production version silently wires to DMA channel 5, rendering it useless. No device driver will be written using DMA if installing a second card into the machine breaks both, and only way to disble the DMA is with a knife. The at1700 driver is in alpha test, and will probably be released with the pl14 kernel. 2.08 Arcnet There is no Arcnet driver for Linux. Feel free to write a driver. With the very low cost and better performance of ethernet, I expect that most places will be giving away their Arcnet hardware for free, resulting in a lot of home systems with Arcnet. An advantage of Arcnet is that all of the cards have identical interfaces, so once a driver is available it will work for everyone. 2.09 Digital / DEC Supported: DE200-64k, DE200-32k, DE202, DE100, DEPCA rev E Peter Bauer has written a driver for the older DEPCA models. Look for depca-0.7.tar.z -- It patches against pl13. This will allow you to use any of the above cards. FvK is currently trying to arrange integration of this driver into pl14, so you *may* not need this file after pl13. If you are using this driver, Peter would like to hear from you. His e-mail addr. is near the start of this document. Peter had this to say about all the DEPCA cards: "In this thing I'll document my knowledge about the digital ethernet boards for PC's: There exist lots of different hardware-releases of ethernet boards of DEC, all subsumed under the keyword 'DEPCA'. All these boards are more or less compatible as they all seem to use some chip called "Lance". The hardware of these cards and the programing of them is documented in a manual purchasable from DEC (about $70 -- I had the order number some months ago, but lost it...)" Unsupported: Digital Etherlink III Again, Peter Bauer said that "the new etherlink III seems to be a break: No official docu from DEC as far as today, other (incompatible??) hardware used, and (no joke) (at least for the first delivered cards) also a sharp knife necessary to get the card working (needs cut of some irq lines ...) As far as I know, lots of DEC Employees use Linux (at least for hobby purposes) and the depca-driver, because its a de-facto standard in DEC, so I encourage any DEC-employee reading this to check wether my writing is true, and to support sources of information about the etherworks-III." 2.10 Intel Ethernet Cards Supported: Ether Express This card uses the intel i82586. An alpha driver is available. Expect to see the driver in the standard release of pl15. 2.11 PureData Supported: PDUC8028, PDI8023 The PureData PDUC8028 and PDI8023 series of cards are reported to work, thanks to special probe code contributed by Mike Jagdis . The support is integrated with the WD driver. 2.12 Xircom Another group that won't release documentation. No cards supported. Don't look for any support in the future unless they release their programming information. And this is highly unlikely, as they *forbid* you from even reverse- engineering their drivers. Here is some of the results from people who have tried to deal with Xircom. "I had no end of problems trying to work with Xircom. After spending months talking to them and working up a prospectus, I was told that no information would be forthcoming and that they were not interested in markets other than the ISA/DOS market. (I was trying to interface the pocket adapters to an Amiga). I won't work with them anymore and I won't recommend their products to anyone." "They (Xircom) won't give it (programming info.) out. BSDI was able to get the spec and write a driver for it, but only by promising not to give out the source." You might also be interested in reading section 9.2 2.13 Zenith The built-in Z-Note network adaptor is based on the Intel i82593 using two DMA channels. There might be a driver for it in early 1994. See section 5.06 for more information. 2.14 Racal-Interlan There is an alpha driver for the NI5210 floating about. (last seen on tsx-11.mit.edu /pub/linux/ALPHA/ni/ni52.tar.gz) This card also uses one of the Intel chips. See section 5.06 for more information. 2.15 AMD LANCE (79C960) There really is no AMD ethernet card. You are probably reading this because the only markings you could find on your card said AMD and the above number. The above number refers to a chip from AMD that is the heart of many ethernet cards. See the section on the Allied Telesis AT1500, the NE1500/2100 and the information in section 5.08. Chances are that the existing LANCE driver will work with all AMD LANCE based cards. 2.16 AT-Lan-Tec AT-Lan-Tec pocket ethernet adaptor: This is a generic, low-cost OEM pocket adaptor being sold by AT-Lan-Tec, and (likely) a number of other suppliers. A driver is in progress, but not yet complete (-djb 11/9/93). 3. Clones of popular Ethernet cards. Due to the popular design of some cards, different companies will make "clones" or replicas of the original card. However, one must be careful, as some of these clones are not 100% compatible, and can be troublesome. Some common problems with "not-quite-clones" are noted in the question and answer section of this document. 3.1 WD80x3 clones The following clones are reported to work with the standard WD80x3 driver: AT-LAN-TEC 8013 PureData (not a 8013 clone, but the 8013 driver has special code) LANNET LEC-45 PE-8013 (WD-8013 Compatible) 3.2 NE2000 clones The following clones are reported to work with the standard NE2000 driver: Accton NE2000 (might not get detected at boot, see section 6) Alta Combo NE2000 clone Aritsoft LANtastic AE-2 (OK, but has flawed error-reporting registers) Asante Etherpak 2001/2003 AT-LAN-TEC NE2000 clone (uses Winbond chip that traps SCSI drivers) Cabletron products: E10**, E10**-x, E20**, E20**-x Cnet UTP 10baseT (NE 2000 emulation) D-Link Ethernet II (bad clones, but the driver checks for them) 4-Dimension FD0490 EtherBoard16 LTC E-NET/16 P/N: 8300-200-002 (lipka@lip.hanse.de) Network Solutions HE-203 SIIG Inc E-Lan/200 (NE 2000 comp.) SVEC 4 Dimension Ethernet 4. Cables, coax, twisted pairs etc. If you are starting a network from scratch, it's considerably less expensive to use thin ethernet, RG58 co-ax cable with BNC connectors, than old-fashioned thick ethernet, RG-5 cable with N connectors, or 10baseT, twisted pair telco-style cables with RJ-45 "phone" connectors. 4.01 Thin Ethernet (thinnet) Thin ethernet is the "ether of choice". The cable is inexpensive. If you are making your own cables solid-core RG58A is $0.09/ft. and stranded RG58AU is $0.15/ft. Twist-on BNC connectors are < $2 ea., and other misc. pieces are similarly inexpensive. It is essential that you properly terminate each end of the cable with 50 ohm terminators, so budget $2 ea. for a pair. It's also vital that your cable have no "stubs" -- the 'T' connectors must be attached directly to the ethercards. 4.02 Twisted pair Twisted pair networks require active hubs, which start around $250, and the raw cable cost can actually be higher than thinnet. They are usually sold using the claim that you can use your existing telephone wiring, but it's a rare installation where that turns out to be the case. The claim that you can upgrade to higher speeds is also suspect, as most proposed schemes use higher-grade (read $$) cable and more sophisticated termination ($$$) than you would likely install on speculation. On the other hand, hubs are rapidly dropping in price, all 100Mb/sec ethernet proposals use twisted pair, and most new business installations use twisted pair. 4.03 Thick Ethernet Thick ethernet is mostly obsolete, and is usually used only to remain compatible with an existing implementation. You can stretch the rules and connect short spans of thick and thin ethernet together with a passive $3 N-to-BNC connector, and that's often the best solution to expanding an existing thicknet. A correct (but expensive) solution is to use a repeater in this case. [End part 1/2] From: Paul Gortmaker Newsgroups: comp.os.linux.announce,comp.os.linux.admin,comp.answers,news.answers Subject: Linux Ethernet HOWTO (Part 2/2) Keywords: Linux, Ethernet, TCP/IP, NET-2 Followup-To: poster Approved: linux-announce@tc.cornell.edu (Matt Welsh) Archive-Name: linux/howto/ethernet/part2 Last-Modified: November 16, 1993 This is part 2/2 of the Linux Ethernet HOWTO. It is archived on sunsite.unc.edu in pub/Linux/docs/HOWTO. [Begin part 2/2] 5 Technical information. For those who want to play with the present drivers, or try to make up their own driver for a card that is presently unsupported, this information should be useful. If you do not fall into this category, then perhaps you will want to skip this section. 5.01 Probed addresses While trying to determine what ethernet card is there, the following addresses are autoprobed, assuming the type and specs of the card have not been set in the kernel. In /usr/src/linux/net/inet/CONFIG, one can set the cards that are compiled in to the kernel. As of 0.99pl12, doing a "make config" will ask what cards are to be supported. The file names below are in /usr/src/linux/net/inet/ ---------------------------------------------------------------- wd.c: 0x300, 0x280, 0x380, 0x240 3c503.c: 0x300, 0x310, 0x330, 0x350, 0x250, 0x280, 0x2a0, 0x2e0 ne.c: 0x300, 0x280, 0x320, 0x340, 0x360 hp.c: 0x300, 0x320, 0x340, 0x280, 0x2C0, 0x200, 0x240 lance.c: 0x300, 0x320, 0x340, 0x360 smc-ultra.c: 0x300, 0x280 3c509.c: ---------------------------------------------------------------- There are some NE2000 clone ethercards out there that are waiting black holes for autoprobe drivers. While many NE2000 clones are safe until they are enabled, some can't be reset to a safe mode. These dangerous ethercards will hang any I/O access to their "dataports". The typical dangerous locations are: Ethercard jumpered base Dangerous locations (base + 0x10 - 0x1f) 0x300 * 0x310-0x317 0x320 0x330-0x337 0x340 0x350-0x357 0x360 0x370-0x377 * The 0x300 location is the traditional place to put an ethercard, but it's also a popular place to put other devices (often SCSI controllers). The 0x320 location is often the next one chosen, but that's bad for for the AHA1542 driver probe. The 0x360 location is bad, because it conflicts with the parallel port at 0x378. To avoid these lurking ethercard, here are the things you can do: o Probe for the device's BIOS in memory space. This is easy and always safe, but it only works for cards that always have BIOSes, like primary SCSI controllers. o Avoid probing any of the above locations until you think you've located your device. The NE2000 clones have a reset range from +0x18 to +0x1f that will read as 0xff, so probe there first if possible. It's also safe to probe in the 8390 space at +0x00 - +0x0f, but that area will return quasi-random values o If you must probe in the dangerous range, for instance if your target device has only a few port locations, first check that there isn't an NE2000 there. You can see how to do this by looking at the probe code in /usr/src/linux/net/inet/ne.c In other news, I've written the code for the I/O port registrar. Peter MacDonald and I have been intensely discussing this, and I think our current scheme has the necessary functionality with minimal kernel size impact. (The implementation involved rewriting the bitmap ops in kernel/ioport.c:ioperm() so that most code could be shared.) Here is the current "blurb". As usual comments are welcome. Please keep them substantial and constructive (we've already talked about changing the name from "reserve=" to "noprobe="). ================== Boot-Time Parameters: "reserve=" In some machines it may be necessary to prevent device drivers from checking for devices (auto-probing) in a specific region. This may be because of poorly designed hardware that causes the boot to "freeze" (such as some ethercards), hardware that is mistakenly identified, hardware whose state is changed by an earlier probe, or merely hardware you don't want the kernel to initialize. The "reserve" boot-time argument addresses this problem by specifying an I/O port region that shouldn't be probed. That region is reserved in the kernel's port registration table as if a device has already been found in that region. Note that this mechanism shouldn't be necessary on most machine, only when there is a problem or special case. The boot-line syntax is lilo-prompt: linux-image reserve=[,,,...] As usual with boot-time specifiers there is an 11 parameter limit, thus you can only specify 5 reserved regions per "reserve" keyword. Multiple "reserve" specifiers will work if you have an usually complicated request. If you specify a "reserve" region to protect a specific device, you must generally specify an explicit probe for that device. Most drivers ignore the port registration table if they are given an explicit address. 5.02 Skeleton / prototype driver OK. So you have decided that you want to write a driver for the Foobar Ethernet card, as you have the programming information, and it hasn't been done yet. (...these are the two main require- ments ;-) You can use the skeleton network driver that is provided with the Linux kernel source tree. It can be found in the file /usr/src/linux/net/inet/README.DRIVERS as of 0.99pl12, and later. It's also very useful to look at the Crynwr (nee Clarkson) driver for your target ethercard, if it's available. Russ Nelson has been actively updating and writing these, and he has been very helpful with his code reviews of the current Linux drivers. 5.03 Driver interface to the kernel Here are some notes that may help when trying to figure out what the code in the driver segments is doing, or perhaps what it is supposed to be doing. ===================================================== int ethif_init(struct device *dev) { ... dev->send_packet = &ei_send_packet; dev->open = &ei_open; dev->stop = &ei_close; dev->hard_start_xmit = &ei_start_xmit; ... } int ethif_init(struct device *dev) This function is put into the device structure in Space.c. It is called only at boot time, and returns '0' iff the ethercard 'dev' exists. ===================================================== static int ei_open(struct device *dev) static int ei_close(struct device *dev) This routine opens and initializes the board in response to an socket ioctl() usually called by 'config' or 'ifconfig'. It is commonly stuffed into the 'struct device' by ethif_init(). The inverse routine is ei_close(), which should shut down the ethercard, free the IRQs and DMA channels if the hardware permits, and turn off anything that will save power (like the transceiver). (Note: As of NET-2, the relevant program is '/etc/ifconfig' - and the device *can* be turned off or on via passing 'up' or 'down' to 'ifconfig' from the command line with the device name.) ===================================================== static int ei_start_xmit(struct sk_buff *skb, struct device *dev) dev->hard_start_xmit = &ei_start_xmit; This routine puts packets to be transmitted into the hardware. It is usually stuffed into the 'struct device' by ethif_init(). When the hardware can't accept additional packets it should set the dev->tbusy flag. When additional room is available, usually during a transmit-complete interrupt, dev->tbusy should be cleared and the higher levels informed with mark_bh(INET_BH). [[Note: pre0.99.4 kernels didn't use this interface for all packets.]] ===================================================== ... if (dev_rint(buffer, length, is_skb ? IN_SKBUFF : 0, dev)) stats->rx_dropped++; ... A received packet is passed to the higher levels using dev_rint(). If the unadorned packet data in a memory buffer, dev_rint will copy it into a 'skbuff' for you. Otherwise a new skbuff should be kmalloc()ed, filled, and passed to dev_rint() with the IN_SKBUFF flag. ===================================================== 5.04 Interrupts and Linux There are two kinds of interrupt handlers in Linux: fast ones and slow ones. You decide what kind you are installing by the flags you pass to irqaction(). The fast ones, such as the serial interrupt handler, run with _all_ interrupts disabled. The normal interrupt handlers, such as the one for ethercard drivers, runs with other interrupts enabled. There is a two-level interrupt structure. The "fast" part handles the device register, removes the packets, and perhaps sets a flag. After it is done, and interrupts are re-enabled, the slow part is run if the flag is set. The flag between the two parts is set by: mark_bh(INET_BH); Usually this flag is set within dev_rint() during a received-packet interrupt, and set directly by the device driver during a transmit-complete interrupt. You might wonder why all interrupt handlers cannot run in "normal mode" with other interrupts enabled. Ross Biro uses this scenario to illustrate the problem: o You get a serial interrupt, and start processing it. The serial interrupt is now masked. o You get a network interrupt, and you start transferring a maximum-sized 1500 byte packet from the card. o Another character comes in, but this time the interrupts are masked! The "fast" interrupt structure solves this problem by allowing bounded-time interrupt handlers to run without the risk of leaving their interrupt lines masked by another interrupt request. There is an additional distinction between fast and slow interrupt handlers -- the arguments passed to the handler. A "slow" handler is defined as static void handle_interrupt(int reg_ptr) { int irq = -(((struct pt_regs *)reg_ptr)->orig_eax+2); struct device *dev = irq2dev_map[irq]; ... While a fast handler gets the interrupt number directly static void handle_fast_interrupt(int irq) { ... A final aspect of network performance is latency. The only board that really addresses this is the 3c509, which allows a predictive interrupt to be posted. It provides an interrupt response timer so that the driver can fine-tune how early an interrupt is generated. Alan Cox has some advice for anyone wanting to write drivers that are to be used with pl14 kernels and newer. He says: "Any driver intended for pl14 should use the new alloc_skb() and kfree_skbmem() functions rather than using kmalloc() to obtain an sk_buff. The new pl14 skeleton does this correctly. For drivers wishing to remain compatible with both sets the define 'HAVE_ALLOC_SKB' indicates these functions must be used. In essence replace skb=(struct sk_buff *)kmalloc(size) with skb=alloc_skb(size) and kfree_s(skb,size) with kfree_skbmem(skb,size) /* Only sk_buff memory though */ Any questions should I guess be directed to me since I made the change. This is a change to allow tracking of sk_buff's and sanity checks on buffers and stack behaviour. If a driver produces the message 'File: ??? Line: ??? passed a non skb!' then it is probable the driver is not using the new sk_buff allocators." 5.05 Programmed I/O vs. shared mem. vs. slave/master DMA Ethernet is 10Mbs. (Don't be pedantic, 3Mbs and 100Mbs don't count.) If you can already send and receive back-to-back packets, you just can't put more bits over the wire. Every modern ethercard can receive back-to-back packets. The Linux DP8390 drivers come pretty close to sending back-to-back packets (depending on the current interrupt latency) and the 3c509 and AT1500 hardware has no problem at all automatically sending back-to-back packets. The ISA bus can do 5.3MB/sec (42Mb/sec), which sounds like more than enough. You can use that bandwidth in several ways: Programmed I/O ============== Pro: Doesn't use any constrained system resources, just a few I/O registers, and has no 16M limit. Con: Usually the slowest transfer rate, the CPU is waiting the whole time, and interleaved packet access is usually difficult to impossible. Shared memory ============= Pro: Simple, faster than programmed I/O, and allows random access to packets. Con: Uses up memory space (a big one for DOS users, only a minor issue under Linux), and it still ties up the CPU. Slave (normal) DMA ================== Pro: Frees up the CPU during the actual data transfer. Con: Checking boundary conditions, allocating contiguous buffers, and programming the DMA registers makes it the slowest of all techniques. It also uses up a scarce DMA channel, and requires aligned low memory buffers. Master (bus-master) DMA ======================= Pro: Frees up the CPU during the data transfer, can string together buffers, can require little or no CPU time lost on the ISA bus. Con: Requires low-memory buffers and a DMA channel. Any bus-master will have problems with other bus-masters that are bus-hogs, such as some primitive SCSI adaptors. A few badly-designed motherboard chipsets have problems with bus-masters. And a reason for not using *any* type of DMA device is using a Cyrix 486 processor designed for plug-in replacement of a 386: these processors must flush their cache with each DMA cycle. 5.06 Programming the Intel chips (i82586 and i82593) These chips are used on a number of cards, namely the 3c507 ('86), the Intel EtherExpress 16 ('86), Microdyne's exos205t ('86), the Z-Note ('93), and the Racal-Interlan ni5210 ('86). Russ Nelson writes: "Most boards based on the 82586 can reuse quite a bit of their code. More, in fact, than the 8390-based adapters. There are only three differences between them: o The code to get the Ethernet address, o The code to trigger CA on the 82586, and o The code to reset the 82586. The Intel EtherExpress 16 is an exception, as it I/O maps the 82586. Yes, I/O maps it. Fairly clunky, but it works. Garrett Wollman did an AT&T driver for BSD that uses the BSD copyright. The latest version I have (Sep '92) only uses a single transmit buffer. You can and should do better than this if you've got the memory. The AT&T and 3c507 adapters do; the ni5210 doesn't. The people at Intel gave me a very big clue on how you queue up multiple transmit packets. You set up a list of NOP->XMIT->NOP->XMIT->NOP->XMIT->(beginning) blocks, then you set the "next" pointer of all the NOP blocks to themselves. Now you start the command unit on this chain. It continually processes the first NOP block. To transmit a packet, you stuff it into the next transmit block, then point the NOP to it. To transmit the next packet, you stuff the next transmit block and point the previous NOP to *it*. In this way, you don't have to wait for the previous transmit to finish, you can queue up multiple packets without any ambiguity as to whether it got accepted, and you can avoid the command unit start-up delay." 5.07 Technical information from 3Com From: Cameron Spitzer 764-6339 Subject: getting 3Com Adapter manuals Date: Mon, 27 Sep 1993 21:17:07 +0200 Since this is becoming a FAQ, I'm going to tread the thin ice of No Commercial Use and answer it here. 3Com's Ethernet Adapters are documented for driver writers in our "Technical References" (TRs). These manuals describe the programmer interfaces to the boards but they don't talk about the diagnostics, installation programs, etc that end users can see. The Network Adapter Division marketing department has the TRs to give away. To keep this program efficient, we centralized it in a thing called "CardFacts." CardFacts is an automated phone system. You call it with a touch-tone phone and it faxes you stuff. To get a TR, call CardFacts at 408-727-7021. Ask it for Developer's Order Form, document number 9070. Have your fax number ready when you call. Fill out the order form and fax it to 408-764-5004. Manuals are shipped by Federal Express 2nd Day Service. If you don't have a fax and nobody you know has a fax, really and truly, *then* send mail to Terry_Murphy@3Mail.3Com.com and tell her about your problem. PLEASE use the fax thing if you possibly can. After you get a manual, if you still can't figure out how to program the board, try our "CardBoard" BBS at 1-800-876-3266, and if you can't do that, write Andy_Chan@3Mail.3com.com and ask him for alternatives. If you have a real stumper that nobody has figured out yet, the fellow who needs to know about it is Steve_Lebus@3Mail.3com.com. There are people here who think we are too free with the manuals, and they are looking for evidence that the system is too expensive, or takes too much time and effort. That's why it's important to try to use CardFacts *before* you start calling and mailing the people I named here. There are even people who think we should be like Diamond and Xircom, requiring tight "partnership" with driver writers to prevent poorly performing drivers from getting written. So far, 3Com customers have been really good about this, and there's no problem with the level of requests we've been getting. We need your continued cooperation and restraint to keep it that way. Cameron Spitzer, 408-764-6339 3Com NAD Santa Clara work: camerons@nad.3com.com home: cls@truffula.sj.ca.us 5.08 Notes on AMD PCnet-ISA / LANCE Based cards (79C960) The AMD LANCE (Local Area Network Controller for Ethernet) was the original offering, and has since been replaced by the "PCnet-ISA" chip, otherwise known as the 79C960. A relatively new chip from AMD, the 79C960, is the heart of many new cards being released at present. Note that the name "LANCE" has stuck, and some people will refer to the new chip by the old name. Dave Roberts of the Network Products Division of AMD was kind enough to contribute the following information regarding this chip: "As for the architecture itself, AMD developed it originally and reduced it to a single chip -- the PCnet(tm)-ISA -- over a year ago. It's been selling like hotcakes ever since. Functionally, it is equivalent to a NE1500. The register set is identical to the old LANCE with the 1500/2100 architecture additions. Older 1500/2100 drivers will work on the PCnet-ISA. The NE1500 and NE2100 architecture is basically the same. Initially Novell called it the 2100, but then tried to distinguish between coax and 10BASE-T cards. Anything that was 10BASE-T only was to be numbered in the 1500 range. That's the only difference. Many companies offer PCnet-ISA based products, including HP, Racal-Datacom, Allied Telesis, Boca Research, Kingston Technology, etc. The cards are basically the same except that some manufacturers have added "jumperless" features that allow the card to be configured in software. Most have not. AMD offers a standard design package for a card that uses the PCnet-ISA and many manufacturers use our design without change. What this means is that anybody who wants to write drivers for most PCnet-ISA based cards can just get the data-sheet from AMD. Call our literature distribution center at (800)222-9323 and ask for the Am79C960, PCnet-ISA data sheet. It's free. A quick way to understand whether the card is a "stock" card is to just look at it. If it's stock, it should just have one large chip on it, a crystal, a small IEEE address PROM, possibly a socket for a boot ROM, and a connector (1, 2, or 3, depending on the media options offered). Note that if it's a coax card, it will have some transceiver stuff built onto it as well, but that should be near the connector and away from the PCnet-ISA. The PCnet-ISA is faster than the original LANCE design and makes better use of the available bus bandwidth. Additionally, some LANCE bugs were corrected and many enhancements were made." 5.09 Multicast and Promiscuous mode One of the things I've been working on recently is the major remaining item on the ethercard feature list: implementing multicast and promiscuous mode hooks. At first I was planning to do it while implementing either the /dev/* or DDI interface, but that's not really the correct way to do it. We should only enable multicast or promiscuous modes when something wants to look at the packets, and shut it down when that application is finished, neither of which is strongly related to when the hardware is opened or released. I'll start by discussing promiscuous mode, which is conceptually easy to implement. For most hardware you only have to set a register bit, and from then on you get every packet on the wire. Well, it's almost that easy; for some hardware you have to shut the board (potentially dropping a few packet), reconfigure it, and then re-enable the ethercard. This is grungy and risky, but the alternative seems to be to have every application register before you open the ethercard at boot-time. OK, so that's easy, so I'll move on something that's not quite so obvious: Multicast. It can be done two ways: 1) Use promiscuous mode, and a packet filter like the Berkeley packet filter (BPF). The BPF is a pattern matching stack language, where you write a program that picks out the addresses you are interested in. Its advantage is that it's very general and programmable. Its disadvantage is that there is no general way for the kernel to avoid turning on promiscuous mode and running every packet on the wire through every registered packet filter. See the next section for more information on BPF. 2) Using the built-in multicast filter that most etherchips have. I guess I should list what a few ethercards/chips provide: Chip/card Promiscuous Multicast filter ======================================== Seeq8001/3c501 Yes Binary filter (1) 3Com/3c509 Yes Binary filter (1) 8390 Yes Autodin II six bit hash (2) (3) LANCE Yes Autodin II six bit hash (2) (3) i82586 Yes Hidden Autodin II six bit hash (2) (4) (1) These cards claim to have a filter, but it's a simple yes/no 'accept all multicast packets', or 'accept no multicast packets'. (2) AUTODIN II is the standard ethernet CRC (checksum) polynomial. In this scheme multicast addresses are hashed and looked up in a hash table. If the cooresponding bit is enabled, this packet is accepted. Ethernet packets are laid out so that the hardware to do this is trivial -- you just latch six (usually) bits from the CRC circuit (needed anyway for error checking) after the first six octets (the destination address), and use them as an index into the hash table (six bits == a 64-bit table). (3) These chips use the six bit hash, and must have the table computed and loaded by the host. This means the kernel must include the CRC code. (4) The 82586 uses the six bit hash internally, but it computes the hash table itself from a list of multicast addresses to accept. Note that none of these chips do perfect filtering, and we still need a middle-level module to do the final filtering. Also note that in every case we must keep a complete list of accepted multicast addresses to recompute the hash table when it changes. My first pass at device-level support is detailed in the new outline driver: ftp.super.org:/pub/linux/pl14/skeleton.c Also in that directory you'll find all of my drivers updated to use the proposed promiscuous/multicast mode hook. #ifdef HAVE_MULTICAST static void set_multicast_list(struct device *dev, int num_addrs, void *addrs); #endif . . ethercard_open() { ... #ifdef HAVE_MULTICAST dev->set_multicast_list = &set_multicast_list; #endif ... #ifdef HAVE_MULTICAST /* Set or clear the multicast filter for this adaptor. num_addrs == -1 Promiscuous mode, receive all packets num_addrs == 0 Normal mode, clear multicast list num_addrs > 0 Multicast mode, receive normal and MC packets, and do best-effort filtering. */ static void set_multicast_list(struct device *dev, int num_addrs, void *addrs) { ... Any comments, criticism, etc. are welcome. Alan Cox adds that "...in pl14, user programs can access promiscuous mode but not multicast mode, even though the drivers support both. The ifconfig program allows you to mark an interface 'promisc'." 5.10 The Berkely Packet Filter (BPF) I'm not bitterly opposed to it, but I'm coming to the conclusion that the 'bpf' functionality should not be provided by the kernel, but should be in a (hopefully little-used) compatibility library. For those not in the know: 'bpf' (the Berkeley Packet Filter) is an mechanism for specifying to the kernel networking layers what packets you are interested in. It's implemented as a specialized stack language interpreter built into a low level of the networking code. An application passes a program written in this language to the kernel, and the kernel runs the program on each incoming packet. If the kernel has multiple 'bpf' applications, each program is run on each packet. The problem is that it's difficult to deduce what kind of packets the application is really interested in from the packet filter program, so the general solution is to always run the filter. Imagine a program that registers a 'bpf' program to pick up a low data-rate stream sent to a multicast address. Most ethernet cards have a hardware multicast address filter implemented as a 64 entry hash table that ignores most unwanted multicast packets, so the capability exists to make this a very inexpensive operation. But with the BFP the kernel must switch the interface to promiscuous mode, receive _all_ packets, and run them through this filter. This is work, BTW, that's very difficult to account back to the process requesting the packets. 5.11 Unresolved questions / concerns There may be some benefit from processing packet data as it is transferred to and from the ethercard, especially with very fast processors transferring data to a slow ethercard. As I see it this question has multiple parts: 1) Is there any useful processing power available, perhaps during the ISA bus recovery period, or while the 8390 remote DMA is preparing for another transfer?? 2) Is there any useful but simple work that can be done between/during each word of the copy, such as calculating a CRC, or discarding obviously unwanted packets?? 3) would the complexity of an interface to do this make future ethercard drivers impossible?? There should be a better structure than Space.c Drivers should be able to autoprobe for all installed ethercards rather than just quitting after finding the first. I've written code to do this, but the constant promise (threat?) of DDI has prevented me from making it standard. A related topic is the problem of driver probes corrupting unrelated hardware. Even worse is a probe into a dataport that isn't set up to transfer data, which will freeze the machine. The common suggestion is a boot-time device registry that records already-used I/O ports and shared memory. This has been implemented as of pl13, see section 5.01. 6 Possible problems, and troubleshooting. This section tries to answer any unresolved questions, and not so common solutions to common problems. They are sorted on a "per manufacturer basis". You should have also read the relevant info. from section 1 about your specific card. Section 8 contains more general FAQ's. 6.01 Problems with NE2000 (and clones) "DMA address mismatch" ====================== Is the chip a real NatSemi 8390? (DP8390, DP83901, DP83902 or DP83905)? If not, some clone chips don't correctly implement the transfer verification register. MS-DOS drivers never do error checking, so it doesn't matter to them. Are most of the messages off by a factor of 2? If so: Are you using the NE2000 in a 16 bit slot? Is it jumpered to use only 8 bit transfers? The Linux driver expects a NE2000 to be a 16 bit slot. A NE1000 can be in either size slot. This problem can also occur with some clones, notably D-Link 16 bit cards, that don't have the correct ID bytes in the station address PROM. [[ This should be fixed in pl12.]] Are you running the bus faster than 8Mhz? If you can change the speed (faster or slower), see if that makes a difference. Most NE2000 clones will run at 16Mhz, but some may not. Changing speed can also mask a noisy bus. What other devices are on the bus? If moving the devices around changes the reliability, then you have a bus noise problem -- just what that error message was designed to detect. Congratulations, you've probably found the source of other problems as well. Machine Hangs during Boot. ========================== Problem: The machine hangs during boot right after the "8390..." or "WD...." message. Removing the NE2000 fixes the problem. Solution: Change your NE2000 base address to 0x360 (or 0x340 for pl12 or later kernels.) Alternatively, you can use the new device registrar implemented in pl13 (see section 5.1) Reason: Your NE2000 clone isn't a good enough clone. An active NE2000 is a bottomless pit that will trap any driver autoprobing in its space. The other ethercard drivers take great pain to reset the NE2000 so that it's safe, but some clones cannot be reset. Clone chips to watch out for: Winbond 83C901. Changing the NE2000 to a less-popular address will move it out of the way of other autoprobes, allowing your machine to boot. Problem: The machine hangs during the SCSI probe at boot. Solution: It's the same problem as above, change the ethercard's address, or use the device registrar. Problem: The machine hangs during the soundcard probe at boot. Solution: No, that's really during the silent SCSI probe, and it's the same problem as above. "eth0: DMAing conflict in ne_block_input" ========================================= This bug came from timer-based packet retransmissions. If you got a timer tick _during_ a ethercard RX interrupt, and timer tick tried to retransmit a timed-out packet, you could get a conflict. Because of the design of the NE2000 you would have the machine hang (exactly the same the NE2000-clone boot hangs). Early versions of the driver disabled interrupts for a long time, and didn't have this problem. Later versions are fixed. (ie. kernels after 0.99p9 should be OK.) NE2000 not detected at boot. ============================ A few people have reported a problem with detecting the Accton NE2000. This problem occurs only at boot-time, and the card is later detected at run-time by the identical code my (alpha-test) ne2k diagnostic program. Accton has been very responsive, but I still haven't tracked down what is going on. I've been unable to reproduce this problem with the Accton cards we purchased. If you are having this problem, please send me an immediate bug report. For that matter, if you have an Accton card send me a success report, including the type of the motherboard. I'm especially interested in finding out if this problem moves with the particular ethercard, or stays with the motherboard. 6.02 Problems with WD80*3 cards Detected Non-existent Ethercard =============================== Problem: A WD80*3 is falsely detected. Removing the sound or MIDI card eliminates the "detected" message. Solution: Update your ethercard driver: new versions include an additional sanity check. Reason: Some MIDI ports happen to produce the same checksum as a WD ethercard. Error messages from the 80*3 ============================ Problem: You get messages such as the following with your 80*3: eth0: bogus packet size, status = ........ kmalloc called with impossibly large argument (65400) eth0: Couldn't allocate sk_buff of size 65400 eth0: receiver overrun Reason: There is a shared memory problem. Solution: If the problem is sparodic, you have hardware problems. Typical problems that are easy to fix are board conflicts, having cache or "shadow ROM" enabled for that region, or running your bus faster than 8Mhz. There are also a surprising number of memory failures on ethernet cards, so run a diagnostic program if you have one for your ethercard. If the problem is continual, and you have have to reboot to fix the problem, record the boot-time probe message and mail it to becker@super.org Take particular note of the shared memory location. 6.03 Problems with 3Com cards Choosing the Interrupt of the 3c503 =================================== Problem: The 3c503 picks IRQ n at boot, but this is needed for some other device which needs IRQ n. (eg. CD ROM driver, etc.) Can this be fixed without compiling this into the kernel? Solution: The 3c503 driver probes for a free IRQ line in the order {5, 9/2, 3, 4}, and it should pick a line which isn't being used. The pre-pl12 (SLS 1.02) driver picked the IRQ line at boot-time, and the current driver (pl12) chooses when the card is open()/'ifconfig'ed. Note the "bug" noted in the 3c503 section in 1.01 Alternately, you can fix the IRQ at boot by passing parameters via LILO. The following selects IRQ9, base location 0x300, , and if_port #1 (the external transceiver). lilo: linux ether=9,0x300,0,1,eth0 The following selects IRQ3, probes for the base location, , and the default if_port #0 (the internal transceiver) lilo: linux ether=3,0,0,0,eth0 "3c503: Configured interrupt number XX is out of range." ======================================================== Problem: Whoever built your kernel fixed the ethercard IRQ at XX. Reason: The above is truly evil, and worse than that, it is not necessary. The 3c503 will autoIRQ when it gets "ifconfig"ed, and pick one of IRQ{5, 2/9, 3, 4}. Solution: Use lilo to set the IRQ, or rebuild the kernel, enabling autoIRQ by not specifying the IRQ line. Choosing the output of the 3c503 ================================ Problem: The supplied 3c503 drivers don't use the AUI (thicknet) port. How does one choose it over the default thinnet port? Solution: The 3c503 AUI port can be selected at boot-time with 0.99pl12 and later. The selection is overloaded onto the low bit of the currently-unused dev->rmem_start variable, so a boot-time parameter of: lilo: linux ether=0,0,0,1,eth0 should work. A boot line to force IRQ 5, port base 0x300, and use an external transceiver is: lilo: linux ether=5,0x300,0,1,eth0 7 Networking with a laptop computer There are currently only a few ways to put your laptop on a network. You can use the NET-2 SLIP code (and run at serial line speeds); you can buy one of the few laptops that come with a NE2000-compatible ethercard or PCMCIA slot built-in; you can get a laptop with a docking station and plug in an ISA ethercard; or you can use a parallel port Ethernet adapter such as the D-Link DE-600. 7.01 Option 1 -- using SLIP This is the cheapest solution, but by far the most difficult. Also, you will not get very high transmission rates. Since SLIP is not really related to ethernet cards, it will not be discussed further here. See the NET-2 HOWTO. 7.02 Option 2 -- Built in NE2000 compatible or PCMCIA Ethercard. The second solution severely limits your laptop choices and is fairly expensive. Be sure to read the specifications carefully, you may find that you will have to buy an additional non-standard transceiver to actually put the machine on a network. Anyone who has used a PCMCIA Ethernet card is requested to contact us so that we can add it to this document. Barry Jaspan has started some work on controlling the PCMCIA slot. 7.03 Option 3 -- ISA Ethercard in the Docking Station. I recommend the third solution. Docking stations for laptops typically cost about $250 and provide two full-size ISA slots, two serial and one parallel port. Most (all?) docking stations are powered off of the laptop's batteries, and a few allow adding extra batteries in the docking station if you use short ISA cards. You can add an inexpensive ethercard and enjoy full-speed ethernet performance. 7.04 Option 4 -- Pocket / parallel port adaptors. The "pocket" ethernet adaptors may also fit your need. Until recently they actually costed more than a docking station and cheap ethercard, and most tie you down with a wall-brick power supply. The only pocket adaptor driver right now is for the D-Link. I'm also working on a driver for the AT-LAN-TEC/RealTek pocket adaptor. Most other companies, especially Xircom, treat the programming information as a trade secret, so support will likely be slow in coming. You can sometimes avoid the wall-brick with the adaptors by buying or making a cable that draws power from the laptop's keyboard port. 8 Frequently asked questions Here are some of the more frequently asked questions about using Linux with an Ethernet connection. Some of the more specific questions are sorted on a "per manufacturer basis" and are listed in the "Troubleshooting" section. (section 6). However, since this document is basically "old" by the time you get it, any "new" problems will not appear here instantly. For these, I suggest that you make efficient use of your newsreader. For example, nn users would type nn -xX -s'3c' to get all the news articles in your subscribed list that have "3c" in the subject. (ie. 3com, 3c509, 3c503, etc.) The moral: Read the man page for your newsreader. 8.01 Just the FAQ's ma'am -- just the FAQ's. Q: I heard that there is an alpha driver available for my card. Where can I get it? A: Assuming that it is a djb driver, it will be on ftp.super.org in the /pub/linux/ area. Things change here quite frequently, so just look around for it. There is usually only about 3 subdirs, so you should be able to find it. Now, if it really is an alpha, or pre-alpha driver, then please treat it as such. In other words, don't complain because you can't figure out what to do with it. If you can't figure out how to install it, then you probably shouldn't be testing it. Also, if it brings your machine down, don't complain. Instead, send us a well documented bug report, or even better, a patch! Q: Is there token ring support for Linux? A: No, there is no token ring support in Linux. To support token ring requires more than only a writing a device driver, it also requires writing the source routing routines for token ring. Given that token ring is expensive, not fast, and will probably be swept away by 100baseVG in a few months, it doesn't seem worth it to write a driver. In case anyone wants to, I looked at writing a token ring device driver, and concluded that the hardware interface wasn't too difficult to do, but writing the support for source routing would take significantly longer than I was willing to spend on an expensive and dying technology. Alan Cox adds: "It will require [...] changes to the bottom socket layer to support 802.2 and 802.2 based TCP/IP. Don't expect anything soon." Q: Is there IPX or Novell support available for Linux? A: Alan Cox writes: "The novell protocols are available from novell for various amounts. IPX is freely documented. SPX is about $1000 but I'm told Xerox SPP is identical. _PLEASE_ has anyone got any freely distributable Xerox SPP code/documentation? The novell server spec costs you $15000 + royalties providing you only want to write a client, or $30000 + royalties otherwise. Needless to say the final output has to be binary only and subject to a novell license. Reading their license rules by my interpretation its also impossible for us to do because you would seem to have to bar disassembly of your final result, which is not allowed in the EEC. Bits of NCP are known, and I hope eventually enough will be known to write limited NCP support into Linux, for the moment I'm poking around at IPX, tho this will have to wait until the new network code is finished. An Alpha test IPX protocol layer is available from me (Alan) for pl14 or higher. People are also exploring the issue of NCP and the new Dr Dobbs journal article on the innards of netware has provided a core of good information." As an alternative, Miquel van Smoorenburg suggests the following: "It _is_ possible to set up a dedicated PC running both novell and the PD SOSS server and let it gateway from NFS to novell. This way it is possible to mount the Novell drives on the Unix client. SOSS is a PD (perhaps with some restrictions, but freely available) NFS server for DOS. It includes the PC/IP TCP/IP implementation and runs on a packet driver. I have run both a Novell client (with PDIPX, a Packet Driver IPX) and this SOSS server together successfully." Q: What needs to be done so that Linux can run two ethernet cards? A: The easiest solution is to get 0.99pl13, which already includes the changes described below. You can enable additional ethercards with LILO parameters such as lilo: linux ether=5,0x300,0,1,eth0 ether=15,0x280,eth1 For pre-pl13 you can enable additional ethercards by adding another entry to Space.c, naming it "eth1" instead of "eth0". If you want routing to work well you should use a recent kernel, say 0.99pl11 or later. You may also want to verify that your driver writer kept all of the per-card variables in 'dev->priv'. Most do, but the pl12 AT1500/LANCE driver has a single static low-memory buffer. Q: I have /dev/eth0 as a link to /dev/xxx. Is this right? A: Contrary to the Net-2 HowTo, the files in /dev/* are not used. I originally thought that they might be an OK idea. I've since concluded that they won't work, at least in the documented form. 9 Miscellaneous. Any other associated stuff that didn't fit in anywhere else gets dumped here. It may not be relevant, and it may not be of general interest but it is here anyway. 9.01 The Cabletron story. (...as related by Donald J. Becker) I contacted Cabletron in early December 1992 for programming information (I had called and sent several earlier messages). I was referred through several different people, and each one took several days to respond before they forwarded me to the next. Eventually I was told I should deal with their (outside?) developer Mr. Dev.Null. I persisted, and around March it seemed that I had finally succeed: Cabletron offered to send me an evaluation board (unrequested) and everything I needed to use it (what I wanted). The hardware showed up right away, and I waited, expecting the the programming information information as well. About a month later I contacted them, and they told me that "all I needed to use it" was the standard MS-DOS NDIS drivers, a binary on standard driver disk. The disk envelope was covered in legalese, including no-disassembly, no-reverse-engineering clauses. It was May (and a few email exchanges later) before I figured out that I had been "slow rolled", and had wasted about 20 hours on this particular windmill. The story isn't over yet. People have written to me say they have vetoed several medium-sized purchases from Cabletron based on the lack of Linux drivers. Cabletron must have noticed this because yesterday I got a call _from_ Cabletron (the first!) stating that they will be independently writing a Linux driver. Of course, their lawyers probably haven't read the GPL yet... 9.02 The Xircom story. (...as related by Russ Nelson) From: "Russell Nelson" Subject: Xircom support (horses mouth) Date: Mon, 30 Aug 1993 17:01:04 +0300 Okay, here's the word on Xircom support. I spoke to Dirk Gates, President of Xircom, about the packet driver situation. Yes, the packet driver uses the Crynwr packet driver skeleton, and yes, it's in violation of the GPL. However, it was not Xircom's intention to violate the GPL. They paid Persoft to write a proprietary driver for them, and Persoft used the Clarkson skeleton, alleging that the code was in the public domain. Xircom is unsuable because they were an innocent infringer. I will shortly be sending them a demand letter. If they continue to distribute the driver after they get the letter, they will be in infringement and I can *then* sue them. Xircom has basically the same philosophy as Diamond. The actual hardware interface is reverse-engineerable in the space of a day or so. However, Xircom prefers to write all their own drivers, because badly-written drivers reflect badly on their product. They also perceive a monetary interest in keeping their product proprietary. Xircom would *probably* release the specs at this point if they were approached by an ad-hoc consortium of potential purchasers who required the specs as a condition of purchase. However, I don't think this is the right thing to do. At this point they have already gotten all the proprietary advantage they are going to. Purchasing their product now will only reward their "bad attitude" toward open systems. Much better to purchase from a vendor who appreciates and encourages open systems, such as D-Link. 9.03 Closing If you have found any glaring typos, or outdated info in this document, please let one of us know. Paul Gortmaker Donald J. Becker =========== end of Ethernet HOWTO ============