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>

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 19c5a9a..4c210c2 100644 (file)
--- 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;