cfg80211/mac80211: allow registering for and sending action frames

This implements a new command to register for action frames
that userspace wants to handle instead of the in-kernel
rejection. It is then responsible for rejecting ones that
it decided not to handle. There is no unregistration, but
the socket can be closed for that.

Frames that are not registered for will not be forwarded
to userspace and will be rejected by the kernel, the
cfg80211 API helps implementing that.

Additionally, this patch adds a new command that allows
doing action frame transmission from userspace. It can be
used either to exchange action frames on the current
operational channel (e.g., with the AP with which we are
currently associated) or to exchange off-channel Public
Action frames with the remain-on-channel command.

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

5 files changed, 88 insertions, 14 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index e1731b7c2523..b7116ef84a3b 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1,7 +1,7 @@
 /*
  * mac80211 configuration hooks for cfg80211
  *
- * Copyright 2006, 2007 Johannes Berg <johannes@sipsolutions.net>
+ * Copyright 2006-2010  Johannes Berg <johannes@sipsolutions.net>
  *
  * This file is GPLv2 as found in COPYING.
  */
@@ -1448,6 +1448,15 @@ static int ieee80211_cancel_remain_on_channel(struct wiphy *wiphy,
         return ieee80211_wk_cancel_remain_on_channel(sdata, cookie);
 }
 
+static int ieee80211_action(struct wiphy *wiphy, struct net_device *dev,
+                            struct ieee80211_channel *chan,
+                            enum nl80211_channel_type channel_type,
+                            const u8 *buf, size_t len, u64 *cookie)
+{
+        return ieee80211_mgd_action(IEEE80211_DEV_TO_SUB_IF(dev), chan,
+                                    channel_type, buf, len, cookie);
+}
+
 struct cfg80211_ops mac80211_config_ops = {
         .add_virtual_intf = ieee80211_add_iface,
         .del_virtual_intf = ieee80211_del_iface,
@@ -1496,4 +1505,5 @@ struct cfg80211_ops mac80211_config_ops = {
         .set_bitrate_mask = ieee80211_set_bitrate_mask,
         .remain_on_channel = ieee80211_remain_on_channel,
         .cancel_remain_on_channel = ieee80211_cancel_remain_on_channel,
+        .action = ieee80211_action,
 };
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9dd98b674cbc..241533e1bc03 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -2,7 +2,7 @@
  * Copyright 2002-2005, Instant802 Networks, Inc.
  * Copyright 2005, Devicescape Software, Inc.
  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
- * Copyright 2007-2008  Johannes Berg <johannes@sipsolutions.net>
+ * Copyright 2007-2010  Johannes Berg <johannes@sipsolutions.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -966,6 +966,10 @@ int ieee80211_mgd_deauth(struct ieee80211_sub_if_data *sdata,
 int ieee80211_mgd_disassoc(struct ieee80211_sub_if_data *sdata,
                            struct cfg80211_disassoc_request *req,
                            void *cookie);
+int ieee80211_mgd_action(struct ieee80211_sub_if_data *sdata,
+                         struct ieee80211_channel *chan,
+                         enum nl80211_channel_type channel_type,
+                         const u8 *buf, size_t len, u64 *cookie);
 ieee80211_rx_result ieee80211_sta_rx_mgmt(struct ieee80211_sub_if_data *sdata,
                                           struct sk_buff *skb);
 void ieee80211_send_pspoll(struct ieee80211_local *local,
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index bfc4a5070013..41812a15eea0 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2084,3 +2084,38 @@ int ieee80211_mgd_disassoc(struct ieee80211_sub_if_data *sdata,
 
         return 0;
 }
+
+int ieee80211_mgd_action(struct ieee80211_sub_if_data *sdata,
+                         struct ieee80211_channel *chan,
+                         enum nl80211_channel_type channel_type,
+                         const u8 *buf, size_t len, u64 *cookie)
+{
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+        struct sk_buff *skb;
+
+        /* Check that we are on the requested channel for transmission */
+        if ((chan != local->tmp_channel ||
+             channel_type != local->tmp_channel_type) &&
+            (chan != local->oper_channel ||
+             channel_type != local->oper_channel_type))
+                return -EBUSY;
+
+        skb = dev_alloc_skb(local->hw.extra_tx_headroom + len);
+        if (!skb)
+                return -ENOMEM;
+        skb_reserve(skb, local->hw.extra_tx_headroom);
+
+        memcpy(skb_put(skb, len), buf, len);
+
+        if (!(ifmgd->flags & IEEE80211_STA_MFP_ENABLED))
+                IEEE80211_SKB_CB(skb)->flags |=
+                        IEEE80211_TX_INTFL_DONT_ENCRYPT;
+        IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_NL80211_FRAME_TX |
+                IEEE80211_TX_CTL_REQ_TX_STATUS;
+        skb->dev = sdata->dev;
+        ieee80211_tx_skb(sdata, skb);
+
+        *cookie = (unsigned long) skb;
+        return 0;
+}
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index a177472adc13..a6080d8d72bb 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1856,28 +1856,25 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
         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))
                 return RX_CONTINUE;
 
-        if (!rx->sta)
+        /* drop too small frames */
+        if (len < IEEE80211_MIN_ACTION_SIZE)
                 return RX_DROP_UNUSABLE;
 
-        if (!(rx->flags & IEEE80211_RX_RA_MATCH))
+        if (!rx->sta && mgmt->u.action.category != WLAN_CATEGORY_PUBLIC)
                 return RX_DROP_UNUSABLE;
 
-        if (ieee80211_drop_unencrypted(rx, mgmt->frame_control))
+        if (!(rx->flags & IEEE80211_RX_RA_MATCH))
                 return RX_DROP_UNUSABLE;
 
-        /* drop too small frames */
-        if (len < IEEE80211_MIN_ACTION_SIZE)
+        if (ieee80211_drop_unencrypted(rx, mgmt->frame_control))
                 return RX_DROP_UNUSABLE;
 
-        /* return action frames that have *only* category */
-        if (len < IEEE80211_MIN_ACTION_SIZE + 1)
-                goto return_frame;
-
         switch (mgmt->u.action.category) {
         case WLAN_CATEGORY_BACK:
                 /*
@@ -1891,6 +1888,10 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
                     sdata->vif.type != NL80211_IFTYPE_AP)
                         break;
 
+                /* verify action_code is present */
+                if (len < IEEE80211_MIN_ACTION_SIZE + 1)
+                        break;
+
                 switch (mgmt->u.action.u.addba_req.action_code) {
                 case WLAN_ACTION_ADDBA_REQ:
                         if (len < (IEEE80211_MIN_ACTION_SIZE +
@@ -1919,6 +1920,10 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
                 if (sdata->vif.type != NL80211_IFTYPE_STATION)
                         break;
 
+                /* verify action_code is present */
+                if (len < IEEE80211_MIN_ACTION_SIZE + 1)
+                        break;
+
                 switch (mgmt->u.action.u.measurement.action_code) {
                 case WLAN_ACTION_SPCT_MSR_REQ:
                         if (len < (IEEE80211_MIN_ACTION_SIZE +
@@ -1954,7 +1959,7 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
                 }
                 break;
         }
- return_frame:
+
         /*
          * For AP mode, hostapd is responsible for handling any action
          * frames that we didn't handle, including returning unknown
@@ -1966,6 +1971,20 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                 return RX_DROP_MONITOR;
 
+        /*
+         * Getting here means the kernel doesn't know how to handle
+         * it, but maybe userspace does ... include returned frames
+         * so userspace can register for those to know whether ones
+         * it transmitted were processed or returned.
+         */
+        status = IEEE80211_SKB_RXCB(rx->skb);
+
+        if (sdata->vif.type == NL80211_IFTYPE_STATION &&
+            cfg80211_rx_action(rx->sdata->dev, status->freq,
+                               rx->skb->data, rx->skb->len,
+                               GFP_ATOMIC))
+                goto handled;
+
         /* do not return rejected action frames */
         if (mgmt->u.action.category & 0x80)
                 return RX_DROP_UNUSABLE;
@@ -1985,7 +2004,8 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
         }
 
  handled:
-        rx->sta->rx_packets++;
+        if (rx->sta)
+                rx->sta->rx_packets++;
         dev_kfree_skb(rx->skb);
         return RX_QUEUED;
 }
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index ded98730c111..56d5b9a6ec5b 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -2,7 +2,7 @@
  * Copyright 2002-2005, Instant802 Networks, Inc.
  * Copyright 2005-2006, Devicescape Software, Inc.
  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
- * Copyright 2008-2009  Johannes Berg <johannes@sipsolutions.net>
+ * Copyright 2008-2010  Johannes Berg <johannes@sipsolutions.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -288,6 +288,11 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
                                         msecs_to_jiffies(10));
         }
 
+        if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX)
+                cfg80211_action_tx_status(
+                        skb->dev, (unsigned long) skb, skb->data, skb->len,
+                        !!(info->flags & IEEE80211_TX_STAT_ACK), GFP_ATOMIC);
+
         /* this was a transmitted frame, but now we want to reuse it */
         skb_orphan(skb);