introduce WEXT scan capabilities

Introduce scan capabilities to WEXT so that userspace can do intelligent
things with scan behavior such as handling hidden SSIDs more gracefully.
If the driver reports a specific scan capability, the driver must
respect the options specified in the iw_scan_req structure when handling
the SIOCSIWSCAN call, unless it's mode or state does not allow it to do
so, in which case it must return an error.

This version switches to Dave Kilroy's suggestion of claiming unused
padding space for the scan_capa field.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 20 insertions, 0 deletions

diff --git a/drivers/net/wireless/hostap/hostap_ioctl.c b/drivers/net/wireless/hostap/hostap_ioctl.c
index d8f5efcfcab9..3a57d48cc360 100644
--- a/drivers/net/wireless/hostap/hostap_ioctl.c
+++ b/drivers/net/wireless/hostap/hostap_ioctl.c
@@ -1089,6 +1089,9 @@ static int prism2_ioctl_giwrange(struct net_device *dev,
         range->enc_capa = IW_ENC_CAPA_WPA | IW_ENC_CAPA_WPA2 |
                 IW_ENC_CAPA_CIPHER_TKIP | IW_ENC_CAPA_CIPHER_CCMP;
 
+        if (local->sta_fw_ver >= PRISM2_FW_VER(1,3,1))
+                range->scan_capa = IW_SCAN_CAPA_ESSID;
+
         return 0;
 }
 
diff --git a/drivers/net/wireless/ipw2200.c b/drivers/net/wireless/ipw2200.c
index 003f73f89efa..be31304dfad5 100644
--- a/drivers/net/wireless/ipw2200.c
+++ b/drivers/net/wireless/ipw2200.c
@@ -8912,6 +8912,8 @@ static int ipw_wx_get_range(struct net_device *dev,
         range->enc_capa = IW_ENC_CAPA_WPA | IW_ENC_CAPA_WPA2 |
                 IW_ENC_CAPA_CIPHER_TKIP | IW_ENC_CAPA_CIPHER_CCMP;
 
+        range->scan_capa = IW_SCAN_CAPA_ESSID | IW_SCAN_CAPA_TYPE;
+
         IPW_DEBUG_WX("GET Range\n");
         return 0;
 }
diff --git a/include/linux/wireless.h b/include/linux/wireless.h
index 0987aa7a6cf5..74e84caa1e20 100644
--- a/include/linux/wireless.h
+++ b/include/linux/wireless.h
@@ -541,6 +541,16 @@
 /* Maximum size of returned data */
 #define IW_SCAN_MAX_DATA        4096    /* In bytes */
 
+/* Scan capability flags - in (struct iw_range *)->scan_capa */
+#define IW_SCAN_CAPA_NONE               0x00
+#define IW_SCAN_CAPA_ESSID              0x01
+#define IW_SCAN_CAPA_BSSID              0x02
+#define IW_SCAN_CAPA_CHANNEL    0x04
+#define IW_SCAN_CAPA_MODE               0x08
+#define IW_SCAN_CAPA_RATE               0x10
+#define IW_SCAN_CAPA_TYPE               0x20
+#define IW_SCAN_CAPA_TIME               0x40
+
 /* Max number of char in custom event - use multiple of them if needed */
 #define IW_CUSTOM_MAX           256     /* In bytes */
 
@@ -963,6 +973,9 @@ struct	iw_range
         __u16           old_num_channels;
         __u8            old_num_frequency;
 
+        /* Scan capabilities */
+        __u8            scan_capa;      /* IW_SCAN_CAPA_* bit field */
+
         /* Wireless event capability bitmasks */
         __u32           event_capa[6];
 
diff --git a/net/mac80211/ieee80211_ioctl.c b/net/mac80211/ieee80211_ioctl.c
index 161f3bdec41b..04ddce76135b 100644
--- a/net/mac80211/ieee80211_ioctl.c
+++ b/net/mac80211/ieee80211_ioctl.c
@@ -218,6 +218,8 @@ static int ieee80211_ioctl_giwrange(struct net_device *dev,
         IW_EVENT_CAPA_SET(range->event_capa, SIOCGIWAP);
         IW_EVENT_CAPA_SET(range->event_capa, SIOCGIWSCAN);
 
+        range->scan_capa |= IW_SCAN_CAPA_ESSID;
+
         return 0;
 }