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>

5 files changed, 51 insertions, 21 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 91f099556ac..dd4c43f512e 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -923,7 +923,7 @@ struct cfg80211_disassoc_request {
  * @privacy: this is a protected network, keys will be configured
  *      after joining
  * @basic_rates: bitmap of basic rates to use when creating the IBSS
- * @mcast_rate: multicast tx rate (in 100 kbps)
+ * @mcast_rate: per-band multicast rate index + 1 (0: disabled)
  */
 struct cfg80211_ibss_params {
         u8 *ssid;
@@ -935,7 +935,7 @@ struct cfg80211_ibss_params {
         u32 basic_rates;
         bool channel_fixed;
         bool privacy;
-        int mcast_rate;
+        int mcast_rate[IEEE80211_NUM_BANDS];
 };
 
 /**
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 5b0fff2178b..08e97e5d03f 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -219,7 +219,7 @@ enum ieee80211_bss_change {
  * @basic_rates: bitmap of basic rates, each bit stands for an
  *      index into the rate table configured by the driver in
  *      the current band.
- * @mcast_rate: multicast rate for AP and Ad-Hoc (in 100 kbps)
+ * @mcast_rate: per-band multicast rate index + 1 (0: disabled)
  * @bssid: The BSSID for this BSS
  * @enable_beacon: whether beaconing should be enabled or not
  * @channel_type: Channel type for this BSS -- the hardware might be
@@ -259,7 +259,7 @@ struct ieee80211_bss_conf {
         u16 assoc_capability;
         u64 timestamp;
         u32 basic_rates;
-        u32 mcast_rate;
+        int mcast_rate[IEEE80211_NUM_BANDS];
         u16 ht_operation_mode;
         s32 cqm_rssi_thold;
         u32 cqm_rssi_hyst;
diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 6fe6837dc13..410d104b134 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -915,7 +915,8 @@ int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 
         sdata->u.ibss.privacy = params->privacy;
         sdata->u.ibss.basic_rates = params->basic_rates;
-        sdata->vif.bss_conf.mcast_rate = params->mcast_rate;
+        memcpy(sdata->vif.bss_conf.mcast_rate, params->mcast_rate,
+               sizeof(params->mcast_rate));
 
         sdata->vif.bss_conf.beacon_int = params->beacon_interval;
 
diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index 76de4f8d932..3d5a2cb835c 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -211,20 +211,11 @@ static bool rc_no_data_or_no_ack(struct ieee80211_tx_rate_control *txrc)
         return (info->flags & IEEE80211_TX_CTL_NO_ACK) || !ieee80211_is_data(fc);
 }
 
-static void rc_send_low_broadcast(s8 *idx, u32 basic_rates, u32 mcast_rate,
+static void rc_send_low_broadcast(s8 *idx, u32 basic_rates,
                                   struct ieee80211_supported_band *sband)
 {
         u8 i;
 
-        if (mcast_rate) {
-                for (i = 0; i < sband->n_bitrates; i++) {
-                        if (sband->bitrates[i].bitrate == mcast_rate) {
-                                *idx = i;
-                                return;
-                        }
-                }
-        }
-
         if (basic_rates == 0)
                 return; /* assume basic rates unknown and accept rate */
         if (*idx < 0)
@@ -247,17 +238,25 @@ bool rate_control_send_low(struct ieee80211_sta *sta,
                            struct ieee80211_tx_rate_control *txrc)
 {
         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
+        struct ieee80211_supported_band *sband = txrc->sband;
+        int mcast_rate;
 
         if (!sta || !priv_sta || rc_no_data_or_no_ack(txrc)) {
                 info->control.rates[0].idx = rate_lowest_index(txrc->sband, sta);
                 info->control.rates[0].count =
                         (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
                         1 : txrc->hw->max_rate_tries;
-                if (!sta && txrc->bss)
+                if (!sta && txrc->bss) {
+                        mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
+                        if (mcast_rate > 0) {
+                                info->control.rates[0].idx = mcast_rate - 1;
+                                return true;
+                        }
+
                         rc_send_low_broadcast(&info->control.rates[0].idx,
                                               txrc->bss_conf->basic_rates,
-                                              txrc->bss_conf->mcast_rate,
-                                              txrc->sband);
+                                              sband);
+                }
                 return true;
         }
         return false;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b15eb77195d..8734efa663d 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,