nl80211: improve station flags handling

It is currently not possible to modify station flags, but that
capability would be very useful. This patch introduces a new
nl80211 attribute that contains a set/mask for station flags,
and updates the internal API (and mac80211) to mirror that.

The new attribute is parsed before falling back to the old so
that userspace can specify both (if it can) to work on all
kernels.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 46 insertions, 20 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index be86e159e6ef..d591a936f5c4 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -629,34 +629,38 @@ static void sta_apply_parameters(struct ieee80211_local *local,
         int i, j;
         struct ieee80211_supported_band *sband;
         struct ieee80211_sub_if_data *sdata = sta->sdata;
+        u32 mask, set;
 
         sband = local->hw.wiphy->bands[local->oper_channel->band];
 
-        /*
-         * FIXME: updating the flags is racy when this function is
-         *        called from ieee80211_change_station(), this will
-         *        be resolved in a future patch.
-         */
+        spin_lock_bh(&sta->lock);
+        mask = params->sta_flags_mask;
+        set = params->sta_flags_set;
 
-        if (params->station_flags & STATION_FLAG_CHANGED) {
-                spin_lock_bh(&sta->lock);
+        if (mask & BIT(NL80211_STA_FLAG_AUTHORIZED)) {
                 sta->flags &= ~WLAN_STA_AUTHORIZED;
-                if (params->station_flags & STATION_FLAG_AUTHORIZED)
+                if (set & BIT(NL80211_STA_FLAG_AUTHORIZED))
                         sta->flags |= WLAN_STA_AUTHORIZED;
+        }
 
+        if (mask & BIT(NL80211_STA_FLAG_SHORT_PREAMBLE)) {
                 sta->flags &= ~WLAN_STA_SHORT_PREAMBLE;
-                if (params->station_flags & STATION_FLAG_SHORT_PREAMBLE)
+                if (set & BIT(NL80211_STA_FLAG_SHORT_PREAMBLE))
                         sta->flags |= WLAN_STA_SHORT_PREAMBLE;
+        }
 
+        if (mask & BIT(NL80211_STA_FLAG_WME)) {
                 sta->flags &= ~WLAN_STA_WME;
-                if (params->station_flags & STATION_FLAG_WME)
+                if (set & BIT(NL80211_STA_FLAG_WME))
                         sta->flags |= WLAN_STA_WME;
+        }
 
+        if (mask & BIT(NL80211_STA_FLAG_MFP)) {
                 sta->flags &= ~WLAN_STA_MFP;
-                if (params->station_flags & STATION_FLAG_MFP)
+                if (set & BIT(NL80211_STA_FLAG_MFP))
                         sta->flags |= WLAN_STA_MFP;
-                spin_unlock_bh(&sta->lock);
         }
+        spin_unlock_bh(&sta->lock);
 
         /*
          * FIXME: updating the following information is racy when this
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 2353ddbf4934..66024ef57bab 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -123,6 +123,9 @@ static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
         [NL80211_ATTR_FREQ_FIXED] = { .type = NLA_FLAG },
         [NL80211_ATTR_TIMED_OUT] = { .type = NLA_FLAG },
         [NL80211_ATTR_USE_MFP] = { .type = NLA_U32 },
+        [NL80211_ATTR_STA_FLAGS2] = {
+                .len = sizeof(struct nl80211_sta_flag_update),
+        },
 };
 
 /* IE validation */
@@ -1334,13 +1337,33 @@ static const struct nla_policy sta_flags_policy[NL80211_STA_FLAG_MAX + 1] = {
         [NL80211_STA_FLAG_MFP] = { .type = NLA_FLAG },
 };
 
-static int parse_station_flags(struct nlattr *nla, u32 *staflags)
+static int parse_station_flags(struct genl_info *info,
+                               struct station_parameters *params)
 {
         struct nlattr *flags[NL80211_STA_FLAG_MAX + 1];
+        struct nlattr *nla;
         int flag;
 
-        *staflags = 0;
+        /*
+         * Try parsing the new attribute first so userspace
+         * can specify both for older kernels.
+         */
+        nla = info->attrs[NL80211_ATTR_STA_FLAGS2];
+        if (nla) {
+                struct nl80211_sta_flag_update *sta_flags;
+
+                sta_flags = nla_data(nla);
+                params->sta_flags_mask = sta_flags->mask;
+                params->sta_flags_set = sta_flags->set;
+                if ((params->sta_flags_mask |
+                     params->sta_flags_set) & BIT(__NL80211_STA_FLAG_INVALID))
+                        return -EINVAL;
+                return 0;
+        }
+
+        /* if present, parse the old attribute */
 
+        nla = info->attrs[NL80211_ATTR_STA_FLAGS];
         if (!nla)
                 return 0;
 
@@ -1348,11 +1371,12 @@ static int parse_station_flags(struct nlattr *nla, u32 *staflags)
                              nla, sta_flags_policy))
                 return -EINVAL;
 
-        *staflags = STATION_FLAG_CHANGED;
+        params->sta_flags_mask = (1 << __NL80211_STA_FLAG_AFTER_LAST) - 1;
+        params->sta_flags_mask &= ~1;
 
         for (flag = 1; flag <= NL80211_STA_FLAG_MAX; flag++)
                 if (flags[flag])
-                        *staflags |= (1<<flag);
+                        params->sta_flags_set |= (1<<flag);
 
         return 0;
 }
@@ -1648,8 +1672,7 @@ static int nl80211_set_station(struct sk_buff *skb, struct genl_info *info)
                 params.ht_capa =
                         nla_data(info->attrs[NL80211_ATTR_HT_CAPABILITY]);
 
-        if (parse_station_flags(info->attrs[NL80211_ATTR_STA_FLAGS],
-                                &params.station_flags))
+        if (parse_station_flags(info, &params))
                 return -EINVAL;
 
         if (info->attrs[NL80211_ATTR_STA_PLINK_ACTION])
@@ -1718,8 +1741,7 @@ static int nl80211_new_station(struct sk_buff *skb, struct genl_info *info)
                 params.ht_capa =
                         nla_data(info->attrs[NL80211_ATTR_HT_CAPABILITY]);
 
-        if (parse_station_flags(info->attrs[NL80211_ATTR_STA_FLAGS],
-                                &params.station_flags))
+        if (parse_station_flags(info, &params))
                 return -EINVAL;
 
         rtnl_lock();