Hello, I tried to understand the following but could not: >> For instance, how do I command a >> channel change from userspace? iw doesn't have that. >Should it? >Yes, it should, and nl80211 even supports it, but iw itself >doesn't yet. >That's fairly easy to fix, too, but then iw won't support actually >telling mac80211 to scan and associate etc. Can you please explain why addition of channel changing in iw will cause iw to not be able to support scanning and association ? (wireless-tools has all this options). Regards, DavidS On Mon, Dec 8, 2008 at 10:13 AM, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > On Sun, 2008-12-07 at 18:29 -0500, Dan E wrote: >> Looking at some of the Linux Wireless website pages it appears as though >> "iw" is meant to be the successor to the older pre-mac80211 userspace >> tools. In that category we have ifconfig, iproute2, iwconfig and >> iwpriv. For an AP there's also hostapd and wpa_supplicant. Probably >> some others I've missed, not to mention Network Manager. I can see how >> configuration and setup wouldn't necessarily be limited to "iw" using >> nl/cfg80211, but in the short term is that the tool of choice for >> migrating the functionality of the old tools to the new mac80211 >> infrastructure? > > Not really, in the short term, you still are using iwconfig (wireless > extensions) with anything but hostapd. > >> Here's my situation: [snip] > > nice > >> Userspace tools. I want to proceed as if Wireless Extensions never >> existed. Is that even possible? > > No, it's not. > >> For instance, how do I command a >> channel change from userspace? iw doesn't have that. Should it? > > Yes, it should, and nl80211 even supports it, but iw itself doesn't yet. > That's fairly easy to fix, too, but then iw won't support actually > telling mac80211 to scan and associate etc. > >> Or do >> I need to drop back to iwconfig? > > For now. > >> Is iw the preferred command-line way >> to do everything the old tools did, but using nl/cfg80211 instead of >> ioctls? > > Not _yet_. > >> When we get to AP mode, will hostapd be re-written to speak >> nl/cfg80211, or is a new config tool needed? The same questions apply >> to wpa_supplicant. > > That's already been done. The plan is to keep wext compatibility around > though, obviously, so iwconfig will work in the foreseeable future. > >> In general, what's the way forward for new userspace tools? nl80211 and >> cfg80211 are a given, I understand that, but what's the recommended >> approach from the perspective of a developer looking to make a clean >> break from Wireless Extensions with a new cleanroom driver written from >> scratch with no pre-existing baggage to worry about? Start making >> additions to iw's capabilities? Adapt some other existing tool to use >> nl/cfg80211, or write something completely new? > > If you're writing a mac80211-based driver, there's no point where you > could possibly get in touch with the userspace API. You're writing the > driver completely to mac80211's internal driver API, and mac80211 > completely shields you from the userspace API. You'll never interact > with either wireless extensions or nl80211. > >> If somone could answer only 1 question (okay, it's a two-parter) the one >> I would most like answered is this: How does one, from userspace, ask >> the driver to switch to a specific channel, and what callback(s) from >> mac80211 should my driver expect to receive as a result? > > iwconfig wlan0 channel 7 > > then mac80211 calls your _ops->config() with the channel flag. Have you > looked at the mac80211 book and the other documentation on > http://wireless.kernel.org/? > > johannes > -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
