mac80211: allow driver to prevent two stations w/ same address

Some devices or drivers cannot deal with having the same station
address for different virtual interfaces, say as a client to two
virtual AP interfaces. Rather than requiring each driver with a
limitation like that to enforce it, add a hardware flag for it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 760bc4d..8628118 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1901,6 +1901,11 @@ struct ieee80211_txq {
  * @IEEE80211_HW_BEACON_TX_STATUS: The device/driver provides TX status
  *     for sent beacons.
  *
+ * @IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR: Hardware (or driver) requires that each
+ *     station has a unique address, i.e. each station entry can be identified
+ *     by just its MAC address; this prevents, for example, the same station
+ *     from connecting to two virtual AP interfaces at the same time.
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -1936,6 +1941,7 @@ enum ieee80211_hw_flags {
        IEEE80211_HW_TDLS_WIDER_BW,
        IEEE80211_HW_SUPPORTS_AMSDU_IN_AMPDU,
        IEEE80211_HW_BEACON_TX_STATUS,
+       IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR,
 
        /* keep last, obviously */
        NUM_IEEE80211_HW_FLAGS

diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index 4d2aaeb..abbdff0 100644 (file)
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -125,6 +125,7 @@ static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = {
        FLAG(TDLS_WIDER_BW),
        FLAG(SUPPORTS_AMSDU_IN_AMPDU),
        FLAG(BEACON_TX_STATUS),
+       FLAG(NEEDS_UNIQUE_STA_ADDR),
 
        /* keep last for the build bug below */
        (void *)0x1

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index f91d187..8f630f5 100644 (file)
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -435,6 +435,19 @@ static int sta_info_insert_check(struct sta_info *sta)
                    is_multicast_ether_addr(sta->sta.addr)))
                return -EINVAL;
 
+       /* Strictly speaking this isn't necessary as we hold the mutex, but
+        * the rhashtable code can't really deal with that distinction. We
+        * do require the mutex for correctness though.
+        */
+       rcu_read_lock();
+       lockdep_assert_held(&sdata->local->sta_mtx);
+       if (ieee80211_hw_check(&sdata->local->hw, NEEDS_UNIQUE_STA_ADDR) &&
+           ieee80211_find_sta_by_ifaddr(&sdata->local->hw, sta->addr, NULL)) {
+               rcu_read_unlock();
+               return -ENOTUNIQ;
+       }
+       rcu_read_unlock();
+
        return 0;
 }
 
@@ -554,14 +567,15 @@ int sta_info_insert_rcu(struct sta_info *sta) __acquires(RCU)
 
        might_sleep();
 
+       mutex_lock(&local->sta_mtx);
+
        err = sta_info_insert_check(sta);
        if (err) {
+               mutex_unlock(&local->sta_mtx);
                rcu_read_lock();
                goto out_free;
        }
 
-       mutex_lock(&local->sta_mtx);
-
        err = sta_info_insert_finish(sta);
        if (err)
                goto out_free;