cfg80211/mac80211: improve ad-hoc multicast rate handling

- store the multicast rate as an index instead of the rate value
  (reduces cpu overhead in a hotpath)
- validate the rate values (must match a bitrate in at least one sband)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 33 insertions, 3 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b15eb77195d8..8734efa663d1 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3600,6 +3600,34 @@ static int nl80211_disassociate(struct sk_buff *skb, struct genl_info *info)
                                       local_state_change);
 }
 
+static bool
+nl80211_parse_mcast_rate(struct cfg80211_registered_device *rdev,
+                         int mcast_rate[IEEE80211_NUM_BANDS],
+                         int rateval)
+{
+        struct wiphy *wiphy = &rdev->wiphy;
+        bool found = false;
+        int band, i;
+
+        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
+                struct ieee80211_supported_band *sband;
+
+                sband = wiphy->bands[band];
+                if (!sband)
+                        continue;
+
+                for (i = 0; i < sband->n_bitrates; i++) {
+                        if (sband->bitrates[i].bitrate == rateval) {
+                                mcast_rate[band] = i + 1;
+                                found = true;
+                                break;
+                        }
+                }
+        }
+
+        return found;
+}
+
 static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
 {
         struct cfg80211_registered_device *rdev = info->user_ptr[0];
@@ -3683,9 +3711,11 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
                                 return -EINVAL;
                 }
         }
-        if (info->attrs[NL80211_ATTR_MCAST_RATE])
-                ibss.mcast_rate =
-                        nla_get_u32(info->attrs[NL80211_ATTR_MCAST_RATE]);
+
+        if (info->attrs[NL80211_ATTR_MCAST_RATE] &&
+            !nl80211_parse_mcast_rate(rdev, ibss.mcast_rate,
+                        nla_get_u32(info->attrs[NL80211_ATTR_MCAST_RATE])))
+                return -EINVAL;
 
         if (ibss.privacy && info->attrs[NL80211_ATTR_KEYS]) {
                 connkeys = nl80211_parse_connkeys(rdev,