[HECnet] DECnet for Linux
Johnny Billquist
bqt at softjar.se
Thu Jan 25 14:50:23 PST 2018
On 2018-01-25 20:28, Dave McGuire wrote:
>
> I keep an Ubuntu 12.10 VM running at the museum to use as a hop-off
> point and file transfer system. It sure would be nice to not have to do
> that. :)
Easy. Set up an RSX system instead. Then you can transport files between
DECnet and TCP/IP easily, as well as send/receive mail, and run
interactive terminal sessions, and more... :-)
Johnny
>
> -Dave
>
> On 01/25/2018 01:20 AM, Mark Abene wrote:
>> I'll speak up. I'd use it if it was stable (again).
>>
>> -Mark
>>
>>
>> On Wed, Jan 24, 2018 at 9:54 PM, Dave McGuire <mcguire at neurotica.com
>> <mailto:mcguire at neurotica.com>> wrote:
>>
>>
>> Let me just say that I, for one, am very glad that you are working on
>> this. DECnet under (modern) Linux is something that is very important
>> to me. I know there are others who feel the same way; inexplicably they
>> don't speak up in support of your efforts.
>>
>> Thank you for working on this. Please continue, if you are
>> willing/able.
>>
>> -Dave
>>
>> On 01/24/2018 04:06 PM, Erik Olofsen wrote:
>> > Hi Johnny,
>> >
>> > You're right, and I will also get tired of it...!
>> >
>> > However, being in the current routine of trying various kernels,
>> > I've now arrived at the latest one 4.14.15, something I never
>> > expected to be possible.
>> >
>> > Different things go wrong with different kernels. With the latest
>> > one, I get a lot of kernel messages about things the decnet module
>> > is doing wrong, rather than mysterious failures, so there lies
>> > some hope. Note: I get these messages while DECnet is working!
>> >
>> > So I will continue just a little bit, and I'll be testing this latest
>> > kernel. I hope you won't be getting too many strange packets from
>> RULLFL.
>> > Can I ask you after some days/weeks if you did?
>> >
>> > With the changes in the Linux API, the decnet code has been updated,
>> > even while it was orphaned, so that it compiles; but it hasn't been
>> > tested (of course). I read somewhere that they're going to omit the
>> > decnet source from the tree.
>> >
>> > When I get tired of it, I'll document a bit how to get things working.
>> >
>> > Erik
>> >
>> >
>> > On Tue, Jan 23, 2018 at 11:34:35PM +0100, Johnny Billquist wrote:
>> >> Erik, thanks for all the analyzing.
>> >> This both (to me) shows the issues with a constantly changing
>> internal API
>> >> of the Linux kernel, and that maintaining DECnet for Linux is a
>> constant
>> >> effort and annoyance. If someone is willing to do it, great, but
>> I suspect
>> >> most people will tire after some time.
>> >> Also, we still have the issues with DECnet under Linux in
>> general, where it
>> >> seems it don't work right at all in some situations.
>> >>
>> >> Johnny
>> >>
>> >> On 2018-01-23 13:34, Erik Olofsen wrote:
>> >>> One more note:
>> >>>
>> >>> In the last longterm 3.x.y kernel, 3.18.92, sock_alloc_send_skb()
>> >>> sets the errcode to ENOBUFS even when the sk_buff is allocated
>> >>> successfully. This causes sendmsg() to stop with "No buffer space
>> >>> available". That is easy to fix in dn_alloc_send_pskb().
>> >>>
>> >>>
>> >>> On Mon, Jan 15, 2018 at 09:43:53PM +0100, Erik Olofsen wrote:
>> >>>> Some more notes on this:
>> >>>>
>> >>>> The problem of accessing a Linux machine seems to be related to
>> >>>> the standard mtu of 1500 of a network interface.
>> >>>>
>> >>>> Reducing the maximum packet size to 576 helps;
>> >>>>
>> >>>> https://sourceforge.net/p/linux-decnet/mailman/message/2395733/
>> <https://sourceforge.net/p/linux-decnet/mailman/message/2395733/>
>> >>>>
>> >>>> This can be done using ifconfig or using 576 instead of dst_mtu()
>> >>>> in dn_current_mss() af_decnet.c of the kernel module source.
>> >>>>
>> >>>> tcpdump shows that a large data packet is one byte too long.
>> >>>> Perhaps this occurs because the pad byte in the header is not
>> counted
>> >>>> in dn_mss_from_pmtu() in af_decnet.c; with an additional mtu--
>> >>>> this seems to be fixed.
>> >>>>
>> >>>> Kernel warnings related to dst.h;
>> >>>>
>> >>>> https://www.spinics.net/lists/netdev/msg225996.html
>> <https://www.spinics.net/lists/netdev/msg225996.html>
>> >>>>
>> >>>> indeed disappear by using dst_metric_raw at two places.
>> >>>>
>> >>>> The above was tested with kernel 3.10.17, and can be tested
>> >>>> with http://mim.update.uu.se/hecnet and nodename RULLFL.
>> >>>>
>> >>>> dntype mim::nodenames.dat works very well on a real machine; why
>> >>>> it doesn't work very well with the virtual machine is not really
>> >>>> solved yet...
>> >>>>
>> >>>>
>> >>>> On Wed, Jan 03, 2018 at 04:44:54PM +0100, Johnny Billquist wrote:
>> >>>>> On 2018-01-03 16:02, Erik Olofsen wrote:
>> >>>>>> On a virtual machine with lubuntu 12.04, kernel 3.2.0, I have
>> >>>>>> DECnet for Linux V.2.5.68s working, with dnprogs version 2.65.
>> >>>>>> It is node RULLFL.
>> >>>>>>
>> >>>>>> The daemons and utilities use decnet.conf with node information,
>> >>>>>> so something useful would be to create it from
>> mim::nodenames.dat.
>> >>>>>>
>> >>>>>> On a VAX, TYPEing it works well, but on the Linux machine, dntype
>> >>>>>> hangs after giving parts of the file; dndir mim:: works well.
>> >>>>>>
>> >>>>>> Does anyone have dntype mim::nodenames.dat working properly (with
>> >>>>>> perhaps different versions of the above)?
>> >>>>>
>> >>>>> I can't help, but I can report that trying to read a file from
>> a Linux
>> >>>>> machine on MIM also hangs after a while.
>> >>>>> A big problem with the DECnet/Linux implementation is that the
>> developers
>> >>>>> only ever tested against VMS, and nothing else.
>> >>>>>
>> >>>>> I've known for ages that it does not play well with RSX. But I
>> do not want
>> >>>>> to dig into the Linux implementation.
>> >>>>>
>> >>>>> (The Linux DAP claims to be a VMS system, by the way, which is
>> probably also
>> >>>>> not a good idea. Better if it had claimed to be some Unix
>> derivative.)
>> >>>>>
>> >>>>> Johnny
>> >>>>>
>> >>>>> --
>> >>>>> Johnny Billquist || "I'm on a bus
>> >>>>> || on a psychedelic trip
>> >>>>> email: bqt at softjar.se <mailto:bqt at softjar.se> ||
>> Reading murder books
>> >>>>> pdp is alive! || tryin' to stay hip" - B.
>> Idol
>> >>
>> >>
>> >> --
>> >> Johnny Billquist || "I'm on a bus
>> >> || on a psychedelic trip
>> >> email: bqt at softjar.se <mailto:bqt at softjar.se> ||
>> Reading murder books
>> >> pdp is alive! || tryin' to stay hip" - B. Idol
>>
>>
>> --
>> Dave McGuire, AK4HZ
>> New Kensington, PA
>>
>>
>
>
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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