This is an example of how a devices MAC address could be changed while the interface is up. Currently RTNL and mac80211 both require the interface be down before changing the MAC. After poking around a bit I found that some drivers can actually change the MAC while the iface is up. Allowing user space to do this while the iface is up would elminate a few potential race conditions that arise when changing the MAC from user space. This commit does a few things: - Adds an EXT_FEATURE that user space can check to see if the driver allows this MAC changing. - Adds a new NL80211_ATTR for including a "random mac" to CMD_CONNECT. This MAC is passed down the stack and gets set to the net_device's address. - Set this wiphy extended feature in iwlwifi (just as an example) - Relax checks in mac80211 which check if the interface is running - Set IFF_LIVE_ADDR_CHANGE on net_device. Note: I know setting this where I did is likely not the right way to do it, but for this proof-of-concept it works. With guidance I can move this around to a proper place. James Prestwood (1): RFC: allow mac address change on up iface .../net/wireless/intel/iwlwifi/mvm/mac80211.c | 2 ++ include/net/cfg80211.h | 1 + include/uapi/linux/nl80211.h | 3 +++ net/mac80211/iface.c | 5 ++--- net/wireless/nl80211.c | 9 +++++++++ net/wireless/sme.c | 20 +++++++++++++++++++ 6 files changed, 37 insertions(+), 3 deletions(-) -- 2.17.1
