cfg80211/mac80211: extensible frame processing

Allow userspace to register for more than just
action frames by giving the frame subtype, and
make it possible to use this in various modes
as well.

With some tweaks and some added functionality
this will, in the future, also be usable in AP
mode and be able to replace the cooked monitor
interface currently used in that case.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 96 insertions, 41 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 4fdbed58ca2f..aa41e382bbb3 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1940,13 +1940,36 @@ static void ieee80211_process_sa_query_req(struct ieee80211_sub_if_data *sdata,
 }
 
 static ieee80211_rx_result debug_noinline
+ieee80211_rx_h_mgmt_check(struct ieee80211_rx_data *rx)
+{
+        struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
+
+        /*
+         * From here on, look only at management frames.
+         * Data and control frames are already handled,
+         * and unknown (reserved) frames are useless.
+         */
+        if (rx->skb->len < 24)
+                return RX_DROP_MONITOR;
+
+        if (!ieee80211_is_mgmt(mgmt->frame_control))
+                return RX_DROP_MONITOR;
+
+        if (!(rx->flags & IEEE80211_RX_RA_MATCH))
+                return RX_DROP_MONITOR;
+
+        if (ieee80211_drop_unencrypted_mgmt(rx))
+                return RX_DROP_UNUSABLE;
+
+        return RX_CONTINUE;
+}
+
+static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 {
         struct ieee80211_local *local = rx->local;
         struct ieee80211_sub_if_data *sdata = rx->sdata;
         struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
-        struct sk_buff *nskb;
-        struct ieee80211_rx_status *status;
         int len = rx->skb->len;
 
         if (!ieee80211_is_action(mgmt->frame_control))
@@ -1962,9 +1985,6 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
         if (!(rx->flags & IEEE80211_RX_RA_MATCH))
                 return RX_DROP_UNUSABLE;
 
-        if (ieee80211_drop_unencrypted_mgmt(rx))
-                return RX_DROP_UNUSABLE;
-
         switch (mgmt->u.action.category) {
         case WLAN_CATEGORY_BACK:
                 /*
@@ -2055,17 +2075,36 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
                 goto queue;
         }
 
+        return RX_CONTINUE;
+
  invalid:
-        /*
-         * For AP mode, hostapd is responsible for handling any action
-         * frames that we didn't handle, including returning unknown
-         * ones. For all other modes we will return them to the sender,
-         * setting the 0x80 bit in the action category, as required by
-         * 802.11-2007 7.3.1.11.
-         */
-        if (sdata->vif.type == NL80211_IFTYPE_AP ||
-            sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
-                return RX_DROP_MONITOR;
+        rx->flags |= IEEE80211_MALFORMED_ACTION_FRM;
+        /* will return in the next handlers */
+        return RX_CONTINUE;
+
+ handled:
+        if (rx->sta)
+                rx->sta->rx_packets++;
+        dev_kfree_skb(rx->skb);
+        return RX_QUEUED;
+
+ queue:
+        rx->skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
+        skb_queue_tail(&sdata->skb_queue, rx->skb);
+        ieee80211_queue_work(&local->hw, &sdata->work);
+        if (rx->sta)
+                rx->sta->rx_packets++;
+        return RX_QUEUED;
+}
+
+static ieee80211_rx_result debug_noinline
+ieee80211_rx_h_userspace_mgmt(struct ieee80211_rx_data *rx)
+{
+        struct ieee80211_rx_status *status;
+
+        /* skip known-bad action frames and return them in the next handler */
+        if (rx->flags & IEEE80211_MALFORMED_ACTION_FRM)
+                return RX_CONTINUE;
 
         /*
          * Getting here means the kernel doesn't know how to handle
@@ -2075,10 +2114,44 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
          */
         status = IEEE80211_SKB_RXCB(rx->skb);
 
-        if (cfg80211_rx_action(rx->sdata->dev, status->freq,
-                               rx->skb->data, rx->skb->len,
-                               GFP_ATOMIC))
-                goto handled;
+        if (cfg80211_rx_mgmt(rx->sdata->dev, status->freq,
+                             rx->skb->data, rx->skb->len,
+                             GFP_ATOMIC)) {
+                if (rx->sta)
+                        rx->sta->rx_packets++;
+                dev_kfree_skb(rx->skb);
+                return RX_QUEUED;
+        }
+
+
+        return RX_CONTINUE;
+}
+
+static ieee80211_rx_result debug_noinline
+ieee80211_rx_h_action_return(struct ieee80211_rx_data *rx)
+{
+        struct ieee80211_local *local = rx->local;
+        struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
+        struct sk_buff *nskb;
+        struct ieee80211_sub_if_data *sdata = rx->sdata;
+
+        if (!ieee80211_is_action(mgmt->frame_control))
+                return RX_CONTINUE;
+
+        /*
+         * For AP mode, hostapd is responsible for handling any action
+         * frames that we didn't handle, including returning unknown
+         * ones. For all other modes we will return them to the sender,
+         * setting the 0x80 bit in the action category, as required by
+         * 802.11-2007 7.3.1.11.
+         * Newer versions of hostapd shall also use the management frame
+         * registration mechanisms, but older ones still use cooked
+         * monitor interfaces so push all frames there.
+         */
+        if (!(rx->flags & IEEE80211_MALFORMED_ACTION_FRM) &&
+            (sdata->vif.type == NL80211_IFTYPE_AP ||
+             sdata->vif.type == NL80211_IFTYPE_AP_VLAN))
+                return RX_DROP_MONITOR;
 
         /* do not return rejected action frames */
         if (mgmt->u.action.category & 0x80)
@@ -2097,20 +2170,8 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 
                 ieee80211_tx_skb(rx->sdata, nskb);
         }
-
- handled:
-        if (rx->sta)
-                rx->sta->rx_packets++;
         dev_kfree_skb(rx->skb);
         return RX_QUEUED;
-
- queue:
-        rx->skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
-        skb_queue_tail(&sdata->skb_queue, rx->skb);
-        ieee80211_queue_work(&local->hw, &sdata->work);
-        if (rx->sta)
-                rx->sta->rx_packets++;
-        return RX_QUEUED;
 }
 
 static ieee80211_rx_result debug_noinline
@@ -2121,15 +2182,6 @@ ieee80211_rx_h_mgmt(struct ieee80211_rx_data *rx)
         struct ieee80211_mgmt *mgmt = (void *)rx->skb->data;
         __le16 stype;
 
-        if (!(rx->flags & IEEE80211_RX_RA_MATCH))
-                return RX_DROP_MONITOR;
-
-        if (rx->skb->len < 24)
-                return RX_DROP_MONITOR;
-
-        if (ieee80211_drop_unencrypted_mgmt(rx))
-                return RX_DROP_UNUSABLE;
-
         rxs = ieee80211_work_rx_mgmt(rx->sdata, rx->skb);
         if (rxs != RX_CONTINUE)
                 return rxs;
@@ -2374,7 +2426,10 @@ static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx,
                 if (res != RX_CONTINUE)
                         goto rxh_next;
 
+                CALL_RXH(ieee80211_rx_h_mgmt_check)
                 CALL_RXH(ieee80211_rx_h_action)
+                CALL_RXH(ieee80211_rx_h_userspace_mgmt)
+                CALL_RXH(ieee80211_rx_h_action_return)
                 CALL_RXH(ieee80211_rx_h_mgmt)
 
  rxh_next:
@@ -2527,7 +2582,7 @@ static int prepare_for_handlers(struct ieee80211_sub_if_data *sdata,
                 break;
         case NL80211_IFTYPE_MONITOR:
         case NL80211_IFTYPE_UNSPECIFIED:
-        case __NL80211_IFTYPE_AFTER_LAST:
+        case NUM_NL80211_IFTYPES:
                 /* should never get here */
                 WARN_ON(1);
                 break;