mac80211: remove support for IFF_PROMISC

This support is essentially useless as typically networks are encrypted,
frames will be filtered by hardware, and rate scaling will be done with
the intended recipient in mind. For real monitoring of the network, the
monitor mode support should be used instead.

Removing it removes a lot of corner cases.

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

4 files changed, 12 insertions, 49 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 556051f68ad7..7d12ba5a4a36 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -725,7 +725,6 @@ struct ieee80211_if_mesh {
  * enum ieee80211_sub_if_data_flags - virtual interface flags
  *
  * @IEEE80211_SDATA_ALLMULTI: interface wants all multicast packets
- * @IEEE80211_SDATA_PROMISC: interface is promisc
  * @IEEE80211_SDATA_OPERATING_GMODE: operating in G-only mode
  * @IEEE80211_SDATA_DONT_BRIDGE_PACKETS: bridge packets between
  *      associated stations and deliver multicast frames both
@@ -735,7 +734,6 @@ struct ieee80211_if_mesh {
  */
 enum ieee80211_sub_if_data_flags {
         IEEE80211_SDATA_ALLMULTI                = BIT(0),
-        IEEE80211_SDATA_PROMISC                 = BIT(1),
         IEEE80211_SDATA_OPERATING_GMODE         = BIT(2),
         IEEE80211_SDATA_DONT_BRIDGE_PACKETS     = BIT(3),
         IEEE80211_SDATA_DISCONNECT_RESUME       = BIT(4),
@@ -1211,8 +1209,8 @@ struct ieee80211_local {
 
         atomic_t agg_queue_stop[IEEE80211_MAX_QUEUES];
 
-        /* number of interfaces with corresponding IFF_ flags */
-        atomic_t iff_allmultis, iff_promiscs;
+        /* number of interfaces with allmulti RX */
+        atomic_t iff_allmultis;
 
         struct rate_control_ref *rate_ctrl;
 
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index b4ac596a7cb7..7791a08a560a 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -697,9 +697,6 @@ int ieee80211_do_open(struct wireless_dev *wdev, bool coming_up)
         if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
                 atomic_inc(&local->iff_allmultis);
 
-        if (sdata->flags & IEEE80211_SDATA_PROMISC)
-                atomic_inc(&local->iff_promiscs);
-
         if (coming_up)
                 local->open_count++;
 
@@ -827,13 +824,10 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
         WARN_ON_ONCE((sdata->vif.type != NL80211_IFTYPE_WDS && flushed > 0) ||
                      (sdata->vif.type == NL80211_IFTYPE_WDS && flushed != 1));
 
-        /* don't count this interface for promisc/allmulti while it is down */
+        /* don't count this interface for allmulti while it is down */
         if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
                 atomic_dec(&local->iff_allmultis);
 
-        if (sdata->flags & IEEE80211_SDATA_PROMISC)
-                atomic_dec(&local->iff_promiscs);
-
         if (sdata->vif.type == NL80211_IFTYPE_AP) {
                 local->fif_pspoll--;
                 local->fif_probe_req--;
@@ -1047,12 +1041,10 @@ static void ieee80211_set_multicast_list(struct net_device *dev)
 {
         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
         struct ieee80211_local *local = sdata->local;
-        int allmulti, promisc, sdata_allmulti, sdata_promisc;
+        int allmulti, sdata_allmulti;
 
         allmulti = !!(dev->flags & IFF_ALLMULTI);
-        promisc = !!(dev->flags & IFF_PROMISC);
         sdata_allmulti = !!(sdata->flags & IEEE80211_SDATA_ALLMULTI);
-        sdata_promisc = !!(sdata->flags & IEEE80211_SDATA_PROMISC);
 
         if (allmulti != sdata_allmulti) {
                 if (dev->flags & IFF_ALLMULTI)
@@ -1062,13 +1054,6 @@ static void ieee80211_set_multicast_list(struct net_device *dev)
                 sdata->flags ^= IEEE80211_SDATA_ALLMULTI;
         }
 
-        if (promisc != sdata_promisc) {
-                if (dev->flags & IFF_PROMISC)
-                        atomic_inc(&local->iff_promiscs);
-                else
-                        atomic_dec(&local->iff_promiscs);
-                sdata->flags ^= IEEE80211_SDATA_PROMISC;
-        }
         spin_lock_bh(&local->filter_lock);
         __hw_addr_sync(&local->mc_list, &dev->mc, dev->addr_len);
         spin_unlock_bh(&local->filter_lock);
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index ea31f119234b..b144de971366 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -41,9 +41,6 @@ void ieee80211_configure_filter(struct ieee80211_local *local)
         unsigned int changed_flags;
         unsigned int new_flags = 0;
 
-        if (atomic_read(&local->iff_promiscs))
-                new_flags |= FIF_PROMISC_IN_BSS;
-
         if (atomic_read(&local->iff_allmultis))
                 new_flags |= FIF_ALLMULTI;
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 6e3b564b6dea..99fb5d80e60a 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2331,11 +2331,9 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
         IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_frames);
         ieee80211_add_pending_skb(local, fwd_skb);
  out:
-        if (is_multicast_ether_addr(hdr->addr1) ||
-            sdata->dev->flags & IFF_PROMISC)
+        if (is_multicast_ether_addr(hdr->addr1))
                 return RX_CONTINUE;
-        else
-                return RX_DROP_MONITOR;
+        return RX_DROP_MONITOR;
 }
 #endif
 
@@ -3266,12 +3264,8 @@ static bool prepare_for_handlers(struct ieee80211_rx_data *rx,
                 if (!bssid && !sdata->u.mgd.use_4addr)
                         return false;
                 if (!multicast &&
-                    !ether_addr_equal(sdata->vif.addr, hdr->addr1)) {
-                        if (!(sdata->dev->flags & IFF_PROMISC) ||
-                            sdata->u.mgd.use_4addr)
-                                return false;
-                        status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
-                }
+                    !ether_addr_equal(sdata->vif.addr, hdr->addr1))
+                        return false;
                 break;
         case NL80211_IFTYPE_ADHOC:
                 if (!bssid)
@@ -3285,9 +3279,7 @@ static bool prepare_for_handlers(struct ieee80211_rx_data *rx,
                         return false;
                 } else if (!multicast &&
                            !ether_addr_equal(sdata->vif.addr, hdr->addr1)) {
-                        if (!(sdata->dev->flags & IFF_PROMISC))
-                                return false;
-                        status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
+                        return false;
                 } else if (!rx->sta) {
                         int rate_idx;
                         if (status->flag & (RX_FLAG_HT | RX_FLAG_VHT))
@@ -3309,12 +3301,7 @@ static bool prepare_for_handlers(struct ieee80211_rx_data *rx,
                 } else if (!multicast &&
                            !ether_addr_equal(sdata->dev->dev_addr,
                                              hdr->addr1)) {
-                        /* if we are in promisc mode we also accept
-                         * packets not destined for us
-                         */
-                        if (!(sdata->dev->flags & IFF_PROMISC))
-                                return false;
-                        rx->flags &= ~IEEE80211_RX_RA_MATCH;
+                        return false;
                 } else if (!rx->sta) {
                         int rate_idx;
                         if (status->flag & RX_FLAG_HT)
@@ -3327,12 +3314,8 @@ static bool prepare_for_handlers(struct ieee80211_rx_data *rx,
                 break;
         case NL80211_IFTYPE_MESH_POINT:
                 if (!multicast &&
-                    !ether_addr_equal(sdata->vif.addr, hdr->addr1)) {
-                        if (!(sdata->dev->flags & IFF_PROMISC))
-                                return false;
-
-                        status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
-                }
+                    !ether_addr_equal(sdata->vif.addr, hdr->addr1))
+                        return false;
                 break;
         case NL80211_IFTYPE_AP_VLAN:
         case NL80211_IFTYPE_AP: