Thank you for the answer. On Mon, May 24, 2010 at 6:24 PM, Dan Williams <dcbw@xxxxxxxxxx> wrote: > On Fri, 2010-05-21 at 14:05 -0400, leo liang wrote: >> On Thu, May 20, 2010 at 4:30 PM, Dan Williams <dcbw@xxxxxxxxxx> wrote: >> > On Thu, 2010-05-20 at 15:40 -0400, leo liang wrote: >> >> Hi, >> >> >> >> Does any one know that if the application send "\0" as essid to >> >> mac80211, how it handle this case? >> > >> > What are you trying to do? Are you trying to work with a hidden AP, or >> > do something else? >> >> I want to hide the associated AP name. Or disassociate and do not let >> the interface connect to any AP. > > "I want to hide the associated AP name" > > What do you mean by this? Do you mean make 'iwconfig' or some other > program not report the currently associated AP name? Or do you mean > something else? > > "Or disassociate and do not let..." > > For complete disassociation, you don't need to send an empty BSSID when > using nl80211, just send the disassociate command using nl80211 (in > code) or the 'iw' command. When using WEXT (which is the older > predecessor of nl80211) you need to send a random SSID (ie, 32 random > ascii characters for example) not including \0. That should cause > devices to disassociate from the AP and not attempt to reconnect to it > until you send a new, valid SSID. > >> > >> > An SSID is simply a 32-byte array; the protocol and the stack don't care >> > what's in that array. So while you can't use command-line tools like >> > 'iwconfig' to send an SSID containing a \0, you can use netlink or >> > wpa_supplicant's nl80211 driver to do so. >> >> I checked "iwconfig" source code, if you run "iwconfig wlan0 essid >> off", it will set the first char as "\0". > > Right, iwconfig is pretty old and does not correctly handle empty > BSSIDs. Don't depend on the iwconfig behavior. > > Dan > >> > >> > But in the end, if you're trying to associate with an AP that has an >> > SSID of only '\0', that AP is likely broken or trying to hide it's SSID, >> > and you should be using the real SSID of that AP instead of '\0'. >> > >> > Dan >> > >> > >> > >> -- >> 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 > > > -- 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
