udev renames wireless devices when using wlanconfig/ignores interface names given to wlanconfig

[Charles Burns]

Binary package hint: shorewall

udev misbehaves in Ubuntu when working with wireless LAN cards, incrementing the device number without reason.

Using driver: madwifi

Running the following commands:
#> ifconfig ath0 down
#> wlanconfig ath0 destroy
#> wlanconfig ath0 create wlandev wifi0 wlanmode [sta|adhoc|ap|monitor|wds|ahdemo]
(see http://madwifi.org/wiki/UserDocs/ChangingMode ) will work, but the resulting device is now ath1 (not ath0) even though wlanconfig reports the resulting device as being ath0.

This has been reported several times in the forums. After much hair pulling and the loss of my weekend, it turns out that this seems to be the fault of udev.

A solution is detailed here: http://madwifi.org/wiki/UserDocs/Distro/Debian/TroubleshootingInstallation

...But this solution required modification to work, at least on Gutsy.

The modified (working) solution is:

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1) Modify /etc/udev/rules.d/75-persistent-net-generator.rules

 /etc/udev/rules.d# less 70-persistent-net.rules
Comment the following (shown commented):

#ACTION=="add", SUBSYSTEM=="net", KERNEL=="eth*|ath*|wlan*|ra*|sta*" \
# NAME!="?*", DRIVERS=="?*", GOTO="persistent_net_generator_do"

Replace with the following:

ACTION=="add", SUBSYSTEM=="net", KERNEL=="eth*|Ath*|wlan*|ra*|sta*" \
        NAME!="?*", DRIVERS=="?*", GOTO="persistent_net_generator_do"

Note the change in capitalization from "ath*" to "Ath*". Another solution found was to remove the "ath*" completely. Changing the capitalization appears to have the same effect.

======================
2) Delete or (preferably) move /etc/udev/rules.d/70-persistent-net.rules or in some way get rid of it.

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3) /etc/init.d/udev/reload or reboot the system.

Problem solved. ath0 now stays ath0.