Handles the case when SIOCSIWSCAN specified iw_scan_req.num_channels and
iw_scan_req.channels[].
Signed-off-by: Holger Schurig <[email protected]>
Index: linux-wl/net/wireless/scan.c
===================================================================
--- linux-wl.orig/net/wireless/scan.c 2009-09-09 10:38:58.000000000 +0200
+++ linux-wl/net/wireless/scan.c 2009-09-09 11:59:39.000000000 +0200
@@ -607,6 +607,9 @@ int cfg80211_wext_siwscan(struct net_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_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_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;
On Wed, 2009-09-09 at 13:09 +0200, Holger Schurig wrote:
> Handles the case when SIOCSIWSCAN specified iw_scan_req.num_channels and
> iw_scan_req.channels[].
> +
> + /* 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;
This is a bit weird -- this way you don't report errors if the user
specified frequencies that don't exist. Also, are you sure that it has
to be a frequency as opposed to a channel number?
johannes
> This is a bit weird -- this way you don't report errors if the
> user specified frequencies that don't exist.
Couldn't / shouldn't this done in user-space, e.g. after checking
IWRANGE.
> Also, are you sure that it has to be a frequency as opposed to
> a channel number?
I'm not totally sure, because there's nowhere any documentation
about the exact meanings of fields in "struct iw_freq". My patch
for wpa_supplicant's driver_wext.c only put's a frequency there:
+ req.channel_list[i].m = params->freqs[i] * 100000;
+ req.channel_list[i].e = 1;
+ req.channel_list[i].i = i;
+ req.channel_list[i].flags = 0;
But now that you bring this into my mind, I should have looked
at another consumer of "struct iw_freq", e.g. I should use
cfg80211_wext_freq() like cfg80211_wext_siwfreq() ?!?
I'll prepare some patch.
--
http://www.holgerschurig.de
> This is a bit weird -- this way you don't report errors if the
> user specified frequencies that don't exist.
The old code did this:
Loop over all bands
Loop over all channels
Stick channel to scan request
I simply added this:
Loop over all bands
Loop over all channels
If scan-request hasn't this channel freq: continue
Stick channel to scan request
Now, if I want to report an -EINVAL for every possibly invalid
scan-request channel, I'd have to do this:
If scan-request has freqs:
Loop over all scan-request freqs
Loop over all bands
Loop over all channels
search for freq
if found:
Stick channel to scan request
else:
err = -EINVAL
else:
Loop over all bands
Loop over all channels
Stick channel to scan request
This is considerable code-bloat for such a seldom-used function.
I'd rather do it like this:
Loop over all bands
Loop over all channels
If scan-request hasn't this channel freq: continue
Stick channel to scan request
if no channels:
err = -EINVAL
That's a compromise :-)
--
http://www.holgerschurig.de
On Fri, 2009-09-11 at 09:52 +0200, Holger Schurig wrote:
> Now, if I want to report an -EINVAL for every possibly invalid
> scan-request channel, I'd have to do this:
>
>
> If scan-request has freqs:
> Loop over all scan-request freqs
> Loop over all bands
> Loop over all channels
> search for freq
> if found:
> Stick channel to scan request
> else:
> err = -EINVAL
> else:
> Loop over all bands
> Loop over all channels
> Stick channel to scan request
>
> This is considerable code-bloat for such a seldom-used function.
Doesn't seem that bad considering that the inner loop is already in an
existing function.
> I'd rather do it like this:
>
>
> Loop over all bands
> Loop over all channels
> If scan-request hasn't this channel freq: continue
> Stick channel to scan request
> if no channels:
> err = -EINVAL
>
> That's a compromise :-)
I guess. I'd still prefer the other way, but it's wext, so I don't
really care :)
johannes