cfg80211: allow scanning on specified frequencies when using wext-compatibility

Handles the case when SIOCSIWSCAN specified iw_scan_req.num_channels and
iw_scan_req.channels[].

Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 34 insertions, 7 deletions

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 19c5a9a8d085..4c210c2debc6 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -607,6 +607,9 @@ int cfg80211_wext_siwscan(struct net_device *dev,
         if (!netif_running(dev))
                 return -ENETDOWN;
 
+        if (wrqu->data.length == sizeof(struct iw_scan_req))
+                wreq = (struct iw_scan_req *)extra;
+
         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
 
         if (IS_ERR(rdev))
@@ -619,9 +622,14 @@ int cfg80211_wext_siwscan(struct net_device *dev,
 
         wiphy = &rdev->wiphy;
 
-        for (band = 0; band < IEEE80211_NUM_BANDS; band++)
-                if (wiphy->bands[band])
-                        n_channels += wiphy->bands[band]->n_channels;
+        /* Determine number of channels, needed to allocate creq */
+        if (wreq && wreq->num_channels)
+                n_channels = wreq->num_channels;
+        else {
+                for (band = 0; band < IEEE80211_NUM_BANDS; band++)
+                        if (wiphy->bands[band])
+                                n_channels += wiphy->bands[band]->n_channels;
+        }
 
         creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
                        n_channels * sizeof(void *),
@@ -638,22 +646,41 @@ int cfg80211_wext_siwscan(struct net_device *dev,
         creq->n_channels = n_channels;
         creq->n_ssids = 1;
 
-        /* all channels */
+        /* translate "Scan on frequencies" request */
         i = 0;
         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                 int j;
                 if (!wiphy->bands[band])
                         continue;
                 for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
+
+                        /* If we have a wireless request structure and the
+                         * wireless request specifies frequencies, then search
+                         * for the matching hardware channel.
+                         */
+                        if (wreq && wreq->num_channels) {
+                                int k;
+                                int wiphy_freq = wiphy->bands[band]->channels[j].center_freq;
+                                for (k = 0; k < wreq->num_channels; k++) {
+                                        int wext_freq = wreq->channel_list[k].m / 100000;
+                                        if (wext_freq == wiphy_freq)
+                                                goto wext_freq_found;
+                                }
+                                goto wext_freq_not_found;
+                        }
+
+                wext_freq_found:
                         creq->channels[i] = &wiphy->bands[band]->channels[j];
                         i++;
+                wext_freq_not_found: ;
                 }
         }
 
-        /* translate scan request */
-        if (wrqu->data.length == sizeof(struct iw_scan_req)) {
-                wreq = (struct iw_scan_req *)extra;
+        /* Set real number of channels specified in creq->channels[] */
+        creq->n_channels = i;
 
+        /* translate "Scan for SSID" request */
+        if (wreq) {
                 if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
                         if (wreq->essid_len > IEEE80211_MAX_SSID_LEN)
                                 return -EINVAL;