cfg80211: allow userspace to control supported rates in scan

Some P2P scans are not allowed to advertise
11b rates, but that is a rather special case
so instead of having that, allow userspace
to request the rate sets (per band) that are
advertised in scan probe request frames.

Since it's needed in two places now, factor
out some common code parsing a rate array.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 73 insertions, 19 deletions

diff --git a/net/wireless/core.h b/net/wireless/core.h
index a570ff9214ec..8672e028022f 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -447,6 +447,10 @@ int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
 
 u16 cfg80211_calculate_bitrate(struct rate_info *rate);
 
+int ieee80211_get_ratemask(struct ieee80211_supported_band *sband,
+                           const u8 *rates, unsigned int n_rates,
+                           u32 *mask);
+
 int cfg80211_validate_beacon_int(struct cfg80211_registered_device *rdev,
                                  u32 beacon_int);
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 44a3fc2ce38d..20aa390cf338 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -177,6 +177,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
         [NL80211_ATTR_STA_PLINK_STATE] = { .type = NLA_U8 },
         [NL80211_ATTR_SCHED_SCAN_INTERVAL] = { .type = NLA_U32 },
         [NL80211_ATTR_REKEY_DATA] = { .type = NLA_NESTED },
+        [NL80211_ATTR_SCAN_SUPP_RATES] = { .type = NLA_NESTED },
 };
 
 /* policy for the key attributes */
@@ -3324,7 +3325,6 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
         struct nlattr *attr;
         struct wiphy *wiphy;
         int err, tmp, n_ssids = 0, n_channels, i;
-        enum ieee80211_band band;
         size_t ie_len;
 
         if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
@@ -3344,6 +3344,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
                 if (!n_channels)
                         return -EINVAL;
         } else {
+                enum ieee80211_band band;
                 n_channels = 0;
 
                 for (band = 0; band < IEEE80211_NUM_BANDS; band++)
@@ -3404,6 +3405,8 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
                         i++;
                 }
         } else {
+                enum ieee80211_band band;
+
                 /* all channels */
                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                         int j;
@@ -3450,6 +3453,28 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
                        request->ie_len);
         }
 
+        for (i = 0; i < IEEE80211_NUM_BANDS; i++)
+                request->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1;
+
+        if (info->attrs[NL80211_ATTR_SCAN_SUPP_RATES]) {
+                nla_for_each_nested(attr,
+                                    info->attrs[NL80211_ATTR_SCAN_SUPP_RATES],
+                                    tmp) {
+                        enum ieee80211_band band = nla_type(attr);
+
+                        if (band < 0 || band > IEEE80211_NUM_BANDS) {
+                                err = -EINVAL;
+                                goto out_free;
+                        }
+                        err = ieee80211_get_ratemask(wiphy->bands[band],
+                                                     nla_data(attr),
+                                                     nla_len(attr),
+                                                     &request->rates[band]);
+                        if (err)
+                                goto out_free;
+                }
+        }
+
         request->dev = dev;
         request->wiphy = &rdev->wiphy;
 
@@ -4336,25 +4361,12 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
                         nla_len(info->attrs[NL80211_ATTR_BSS_BASIC_RATES]);
                 struct ieee80211_supported_band *sband =
                         wiphy->bands[ibss.channel->band];
-                int i, j;
-
-                if (n_rates == 0)
-                        return -EINVAL;
-
-                for (i = 0; i < n_rates; i++) {
-                        int rate = (rates[i] & 0x7f) * 5;
-                        bool found = false;
+                int err;
 
-                        for (j = 0; j < sband->n_bitrates; j++) {
-                                if (sband->bitrates[j].bitrate == rate) {
-                                        found = true;
-                                        ibss.basic_rates |= BIT(j);
-                                        break;
-                                }
-                        }
-                        if (!found)
-                                return -EINVAL;
-                }
+                err = ieee80211_get_ratemask(sband, rates, n_rates,
+                                             &ibss.basic_rates);
+                if (err)
+                        return err;
         }
 
         if (info->attrs[NL80211_ATTR_MCAST_RATE] &&
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 1c4672e35144..1e7ff949d1aa 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -862,6 +862,9 @@ int cfg80211_wext_siwscan(struct net_device *dev,
                         creq->n_ssids = 0;
         }
 
+        for (i = 0; i < IEEE80211_NUM_BANDS; i++)
+                creq->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1;
+
         rdev->scan_req = creq;
         err = rdev->ops->scan(wiphy, dev, creq);
         if (err) {
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 4d7b83fbc32f..a329429bfdd8 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1006,3 +1006,38 @@ int cfg80211_can_change_interface(struct cfg80211_registered_device *rdev,
 
         return -EBUSY;
 }
+
+int ieee80211_get_ratemask(struct ieee80211_supported_band *sband,
+                           const u8 *rates, unsigned int n_rates,
+                           u32 *mask)
+{
+        int i, j;
+
+        if (n_rates == 0 || n_rates > NL80211_MAX_SUPP_RATES)
+                return -EINVAL;
+
+        *mask = 0;
+
+        for (i = 0; i < n_rates; i++) {
+                int rate = (rates[i] & 0x7f) * 5;
+                bool found = false;
+
+                for (j = 0; j < sband->n_bitrates; j++) {
+                        if (sband->bitrates[j].bitrate == rate) {
+                                found = true;
+                                *mask |= BIT(j);
+                                break;
+                        }
+                }
+                if (!found)
+                        return -EINVAL;
+        }
+
+        /*
+         * mask must have at least one bit set here since we
+         * didn't accept a 0-length rates array nor allowed
+         * entries in the array that didn't exist
+         */
+
+        return 0;
+}