From 3110489117581a980537b6d999a3724214ba772c Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 22 Oct 2015 17:35:19 +0200 Subject: [PATCH] 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 --- include/net/mac80211.h | 6 ++++++ net/mac80211/debugfs.c | 1 + net/mac80211/sta_info.c | 18 ++++++++++++++++-- 3 files changed, 23 insertions(+), 2 deletions(-) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 760bc4d5a2cf..8628118214cc 100644 --- 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 4d2aaebd4f97..abbdff03ce92 100644 --- 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 f91d1873218c..8f630f51d9bd 100644 --- 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;