Menu
▾
▴
[User-mode-linux-devel] Re: 2.3.51 Networking *smile*
|
From: William S. <wst...@po...> - 2000-03-13 05:14:17
|
Good evening, Jeff, On Sun, 12 Mar 2000, Jeff Dike wrote: > > ifconfig umn 172.20.0.244 pointopoint 172.20.0.253 > > From which the uml-kernel could extract the pointopoint address and > > execute > > > um_ifconfig sl0 172.20.0.253 pointopoint 172.20.0.244 > > I'll look through the networking code again, but when I wrote the driver, my > impression was that the only way to give the driver an address was in the > hardware address, which is why I sneak the IP address in via the ethernet > address. LOL! You're kidding - I just went back and did the conversion and only now reconized that the mac address encoded the IP address. > What I'm going to do about this is add a command line arg like > umn0=172.20.0.253 > > That will let you specify both ends of the slip device (the other is in the > ifconfig command at boot time). How would it be if you used ethertap on the host and uml? Could the uml kernel connect the output of one tap to the input of the other and vice-versa? Granted, this is still a point-to-point approach, but A) I think it's still pretty neat, and B) it would mean the umn device wouldn't have to be used at all. Ethertap's part of any kernel that would support uml and it seems to work pretty reasonably; Rusty uses it for his netfilter testing. Because you'd be feeding the output of one into the input of the other, it almost seems as if you could setup pipes to do the work. > > I suppose Nirvanha would be to have sl0 on the host be able to talk > > to multiple UML's on a simulated ethernet cable: > > host OS sl0: 192.168.12.1/24 > > uml1 umn: 192.168.12.2/24, default route ->1 > > uml2 umn: 192.168.12.3/24, default route ->1 > > uml3 umn: 192.168.12.4/24, default route ->1 > > You're more of a network weenie than I, but I thought that slip devices are > ptp, so each one has two end, and only one machine at each end. My plan for a Ooops, I wasn't paying attention. You're exactly right. It would be ethx on the host and in the umn's. > virtual net has been to use the host machine as a virtual hub rather than as a > virtual ethernet. There would be a slip device for each uml, and the host > machine would be routing packets between them. And for a truly virtual net, > I'm planning on a second driver which just uses normal pipes for umls to talk > directly to each other without routing through the host. Again, would the ethertap serve this purpose? > > How many fhd's are supported? It looks like MAX_DEV is set to 8 in > > the uml patch. > > Is that not enough for you? It was a poorly worded real question, not request. 8 is fine, especially if adjustable. I just wanted to check that I was reading it correctly. > > Do they support partition tables so one might actually mount an entire > > physical hard drive via fhd: > > ./linux fhd1=/dev/hdc > > where /dev/hdc is a partitioned ide drive? > > What good would this be? The host OS already splits the partitions up and > makes them available individually. As one possibility, one could assign an ndb device to fhd1. The fake device at the other end of the network could be (perhaps _must_ be; I don't know) pointing to a physical device with a partition table. Although I'll side with you on limited utility, I still bring it up with the goal of making uml as close to the real thing as possible. > > BTW - what do you think of the term Virtual Block Device as opposed to > > Fake Hard Disk. The former makes me think that I could map vbda=/dev/ > > hdc vbdb=/dev/ndb1 /vbdc=/dev/sr0 /vbdd=/dev/fd1 - anything that is a > > block device, whereas fhd sounds like it can only be a hard disk. > > I like that. I'll switch at some point. > > > Unimplemented syscall : 8 > > Untested (20092) [0x10171428]: syscall_kern.c > > line 696 > > > From unistd.h: #define __NR_creat 8 > > OK, I'll toss that in as well. It sounds like putting these in place is not all that complex. (Didn't I hear once that the mark of the true artist is one that makes the impossible look effortless? I think that's why you rank as a True Hacker in my book.) If it really is a matter of cut and paste, would it be useful to simply enable the remaining syscalls and printk/syslog their use the first time they get called in a given kernel along with a request to mail "syscall 674, at location blah..." to you/the devel list? > > Then start filling up ram with bash's. Around 312K free, the xterm > > with the bashs and the xterm with top freeze, but the console still > > accepts keystrokes: > > usermode:~# > > usermode:~# ps axf | less > Kernel panic: No vma in segv > > I run with swap all the time, but I haven't actually forced it to swap in a > while. I'll check this out. I brought it up because I'm moderately confident that I've never successfully gotten any data into swap space on 2.3.51/2.3.51-uml. > > Jeff - could this make its way into cvs, the downloads section (in > > text and html format; I'd be happy to provide a tar with all three if > > that's useful), and into the debian root_fs package on next release > > (it's still at 0.0.4)? > > I forgot to rebuild the text versions of the HOWTO when I redid the packages. > Next time... :-) Your last changes are available in all their glory in the > html version on the web site... I hadn't looked there, sorry. I'm actually a little surprised that Sourceforge doesn't have a documentation section - they have everything else, and even with cute little icons. :-) Cheers, - Bill --------------------------------------------------------------------------- admin@loopback, $LOGIN@localhost, $LOGNAME@localhost, $USER@localhost, $USER@$HOST,-h1024@localhost,ro...@ma... Chairman Reed Hundt: rh...@fc... Commissioner James Quello: jq...@fc... Commissioner Susan Ness: sn...@fc... Commissioner Rachelle Chong: rc...@fc... US Postal Service: cus...@em... (Courtesy of Arlen Fletcher <fle...@pa...>) -------------------------------------------------------------------------- William Stearns (wst...@po...). Mason, Buildkernel, named2hosts, and ipfwadm2ipchains are at: http://www.pobox.com/~wstearns LinuxMonth; articles for Linux Enthusiasts! http://www.linuxmonth.com -------------------------------------------------------------------------- |
