Ad-Hoc network


Forum: Networking
Topic: Ad-Hoc network
started by: danielp

Posted by danielp on April 21 2008,13:10
Hi all,

I'm trying to set up DSL to accept ad-hoc wifi connections. The goal is to make a picture frame for my workplace. They don't have any wifi access points there, so I have this old laptop with a workable wifi card (IBM 390 + Buffalo WLI-CB-G54S) which is working through ndiswrapper.

What I want to do now is:

1)make the wifi card work ad-hoc
2)use a dhcp server on DSL
3)be able to transfer pictures onto the DSL box from either another laptop or a PocketPC with FTP

I have got most of the parts working:

1)sudo iwconfig wlan0 mode ad-hoc
2)using Curaga's busyserver.tar.gz mydsl extension, but everytime I launch it I get an error message:
udhcpd: cannot open /var/lib/misc/udhcpd.leases for reading
3)using ftp boot code (I'm using frugal install of DSL 4.2.2)

Does anyone have any experience with such a setup? I am wondering if my dhcp.conf file is not ok, or if I'm doing something else wrong?

In the dhcp.conf, I only changed the interface to wlan0 instead of eth0.

Thanks for any help!

Posted by Juanito on April 21 2008,13:49
Does the folder /var/lib/misc/ exist? You might need to create it before busyserver can write to it.
Posted by danielp on April 21 2008,14:29
good idea! No it didn't exist, so I created it. But still, no luck, same error message.

Apparently it's not the only problem, as when I set a manual IP on my pocketPC (in the same subnet), I cannot ping the DSL machine :(
... even though it says I'm connected to the ad-hoc network!

Posted by lucky13 on April 21 2008,15:24
That's another Broadcom 43xx (4318) chip, right? Join the club if it is. You'll get much better support for it in 2.6 than in 2.4 with the versions of wireless extension and wireless tools in DSL.
Posted by danielp on April 21 2008,18:10
Yes, it is a Broadcom 4318 chip. So which club should I join? That of another distro with 2.6 kernel? What are my options?
Posted by lucky13 on April 21 2008,19:15
If you try to scan or take advantage of similar options, you'll likely get error messages related to wireless tools version and limitations from that. That's because support for 2.4 ended several iterations back. Hence the roadblock in DSL, not to mention the problems with the older ndiswrapper version which would require newer gcc, etc., to compile. Lots of work, not much reward (imo).

These are your options...

1. Anything with kernel 2.6.17 and higher works much better with bcm43xx and should have much better wifi support. I'm presently using Vector 5.9 with its stock kernel (2.6.22.14 with novmsplice patch) on my laptop and I've been happy with its wifi support even though I expressed a few points of displeasure about Vector on my blog this morning.
2. DSL will have a new 2.6 option shortly. If you want to wait for that, you might try the third option in the interim.
3. Buy or trade for a card that's better supported and/or has open (or distributable) drivers.
4. OpenBSD 4.3 and DragonFlyBSD 1.12+ have a bwi driver for bcm43xx. I've tested neither yet.

Broadcom-based cards are excellent, but Broadcom chooses to play by their own rules when it comes to open source for various reasons. That's their right. It's also your right to buy hardware from companies that allow users to choose their own operating systems.

Posted by danielp on April 22 2008,10:06
Strange, I posted a reply last night, but it seems to have disappeared.

Anyway, thanks again for your detailed post. My guess is that I'll wait for DSL with 2.6 kernel in the future. This is a long term project anyway, and I don't want to spend any extra money on it right now.

I have looked up a bit HOSTAP and most people talk about Prism 2 chipsets... but are there still pcmcia cards like that available today?

What other chipsets would you recommend? It seems Atheros is a popular choice as well. Specifically, I'd be looking to emulate an AP with DSL on a laptop.

Posted by lucky13 on April 22 2008,12:32
There's a list of wireless cards and USB adapters in the wiki. As far as availability goes, everything is always available -- ebay, craigslist, etc. It also helps if you have any used computer or used laptop stores in your area. I bought my (permanently loaned out) USB wireless adapter for $10 at a used computer store.

edit:
< http://www.damnsmalllinux.org/wiki/index.php/Verified_Wireless_Cards >

Posted by curaga on April 22 2008,15:14
Not many chipsets can do host ap - prism2 and atheros are actually only ones that come to my mind

For the file error, perhaps try creating the file and also chown it and the directory to dsl:staff
Are you running it as root or as dsl? I seem to remember I ran as root when testing and it worked..

Posted by danielp on April 24 2008,16:21
Thanks curaga, I got it working now (indeed had to create the empty file and run as root).

DHCP works over the ad-hoc network now (although for a strange reason, it's taking my pocket pc 30 seconds to recognize the address!). Thanks again all !

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