cfg80211: Store IEs from both Beacon and Probe Response frames

Store information elements from Beacon and Probe Response frames in
separate buffers to allow both sets to be made available through
nl80211. This allows user space applications to get access to IEs from
Beacon frames even if we have received Probe Response frames from the
BSS. Previously, the IEs from Probe Response frames would have
overridden the IEs from Beacon frames.

This feature is of somewhat limited use since most protocols include
the same (or extended) information in Probe Response frames. However,
there are couple of exceptions where the IEs from Beacon frames could
be of some use: TIM IE is only included in Beacon frames (and it would
be needed to figure out the DTIM period used in the BSS) and at least
some implementations of Wireless Provisioning Services seem to include
the full IE only in Beacon frames).

The new BSS attribute for scan results is added to allow both the IE
sets to be delivered. This is done in a way that maintains the
previously used behavior for applications that are not aware of the
new NL80211_BSS_BEACON_IES attribute.

Signed-off-by: Jouni Malinen <j@w1.fi>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 7a1c8c145b22..127a73015760 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -1378,13 +1378,20 @@ enum nl80211_channel_type {
  * @NL80211_BSS_BEACON_INTERVAL: beacon interval of the (I)BSS (u16)
  * @NL80211_BSS_CAPABILITY: capability field (CPU order, u16)
  * @NL80211_BSS_INFORMATION_ELEMENTS: binary attribute containing the
- *      raw information elements from the probe response/beacon (bin)
+ *      raw information elements from the probe response/beacon (bin);
+ *      if the %NL80211_BSS_BEACON_IES attribute is present, the IEs here are
+ *      from a Probe Response frame; otherwise they are from a Beacon frame.
+ *      However, if the driver does not indicate the source of the IEs, these
+ *      IEs may be from either frame subtype.
  * @NL80211_BSS_SIGNAL_MBM: signal strength of probe response/beacon
  *      in mBm (100 * dBm) (s32)
  * @NL80211_BSS_SIGNAL_UNSPEC: signal strength of the probe response/beacon
  *      in unspecified units, scaled to 0..100 (u8)
  * @NL80211_BSS_STATUS: status, if this BSS is "used"
  * @NL80211_BSS_SEEN_MS_AGO: age of this BSS entry in ms
+ * @NL80211_BSS_BEACON_IES: binary attribute containing the raw information
+ *      elements from a Beacon frame (bin); not present if no Beacon frame has
+ *      yet been received
  * @__NL80211_BSS_AFTER_LAST: internal
  * @NL80211_BSS_MAX: highest BSS attribute
  */
@@ -1400,6 +1407,7 @@ enum nl80211_bss {
         NL80211_BSS_SIGNAL_UNSPEC,
         NL80211_BSS_STATUS,
         NL80211_BSS_SEEN_MS_AGO,
+        NL80211_BSS_BEACON_IES,
 
         /* keep last */
         __NL80211_BSS_AFTER_LAST,