mac80211: Add cooked monitor mode support

This adds "cooked" monitor mode to mac80211. A monitor interface
in "cooked" mode will see all frames that mac80211 has not used
internally.

Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 78fd91895c80ab1a0e0f805fec3058db0370a6cf..91f06c3f4a7c304548015b600acdb588dc60b642 100644 (file)
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -239,6 +239,11 @@ static int ieee80211_open(struct net_device *dev)
                /* no need to tell driver */
                break;
        case IEEE80211_IF_TYPE_MNTR:
+               if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
+                       local->cooked_mntrs++;
+                       break;
+               }
+
                /* must be before the call to ieee80211_configure_filter */
                local->monitors++;
                if (local->monitors == 1)
@@ -370,6 +375,11 @@ static int ieee80211_stop(struct net_device *dev)
                /* no need to tell driver */
                break;
        case IEEE80211_IF_TYPE_MNTR:
+               if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
+                       local->cooked_mntrs--;
+                       break;
+               }
+
                local->monitors--;
                if (local->monitors == 0)
                        local->hw.conf.flags &= ~IEEE80211_CONF_RADIOTAP;
@@ -1177,7 +1187,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb,
        u16 frag, type;
        struct ieee80211_tx_status_rtap_hdr *rthdr;
        struct ieee80211_sub_if_data *sdata;
-       int monitors;
+       struct net_device *prev_dev = NULL;
 
        if (!status) {
                printk(KERN_ERR
@@ -1290,7 +1300,11 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb,
        /* this was a transmitted frame, but now we want to reuse it */
        skb_orphan(skb);
 
-       if (!local->monitors) {
+       /*
+        * This is a bit racy but we can avoid a lot of work
+        * with this test...
+        */
+       if (!local->monitors && !local->cooked_mntrs) {
                dev_kfree_skb(skb);
                return;
        }
@@ -1324,42 +1338,37 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb,
 
        rthdr->data_retries = status->retry_count;
 
+       /* XXX: is this sufficient for BPF? */
+       skb_set_mac_header(skb, 0);
+       skb->ip_summed = CHECKSUM_UNNECESSARY;
+       skb->pkt_type = PACKET_OTHERHOST;
+       skb->protocol = htons(ETH_P_802_2);
+       memset(skb->cb, 0, sizeof(skb->cb));
+
        rcu_read_lock();
-       monitors = local->monitors;
        list_for_each_entry_rcu(sdata, &local->interfaces, list) {
-               /*
-                * Using the monitors counter is possibly racy, but
-                * if the value is wrong we simply either clone the skb
-                * once too much or forget sending it to one monitor iface
-                * The latter case isn't nice but fixing the race is much
-                * more complicated.
-                */
-               if (!monitors || !skb)
-                       goto out;
-
                if (sdata->vif.type == IEEE80211_IF_TYPE_MNTR) {
                        if (!netif_running(sdata->dev))
                                continue;
-                       monitors--;
-                       if (monitors)
+
+                       if (prev_dev) {
                                skb2 = skb_clone(skb, GFP_ATOMIC);
-                       else
-                               skb2 = NULL;
-                       skb->dev = sdata->dev;
-                       /* XXX: is this sufficient for BPF? */
-                       skb_set_mac_header(skb, 0);
-                       skb->ip_summed = CHECKSUM_UNNECESSARY;
-                       skb->pkt_type = PACKET_OTHERHOST;
-                       skb->protocol = htons(ETH_P_802_2);
-                       memset(skb->cb, 0, sizeof(skb->cb));
-                       netif_rx(skb);
-                       skb = skb2;
+                               if (skb2) {
+                                       skb2->dev = prev_dev;
+                                       netif_rx(skb2);
+                               }
+                       }
+
+                       prev_dev = sdata->dev;
                }
        }
- out:
+       if (prev_dev) {
+               skb->dev = prev_dev;
+               netif_rx(skb);
+               skb = NULL;
+       }
        rcu_read_unlock();
-       if (skb)
-               dev_kfree_skb(skb);
+       dev_kfree_skb(skb);
 }
 EXPORT_SYMBOL(ieee80211_tx_status);
 

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 1129a4299de796f63654df5bfe7a4c72103555d3..1b4a4497030d8100650db3464fdd9525053ed80d 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -131,6 +131,7 @@ typedef unsigned __bitwise__ ieee80211_rx_result;
 #define IEEE80211_TXRXD_RXRA_MATCH             BIT(5)
 #define IEEE80211_TXRXD_TX_INJECTED            BIT(6)
 #define IEEE80211_TXRXD_RX_AMSDU               BIT(7)
+#define IEEE80211_TXRXD_RX_CMNTR_REPORTED      BIT(8)
 struct ieee80211_txrx_data {
        struct sk_buff *skb;
        struct net_device *dev;
@@ -419,7 +420,7 @@ struct ieee80211_local {
 
        struct net_device *mdev; /* wmaster# - "master" 802.11 device */
        int open_count;
-       int monitors;
+       int monitors, cooked_mntrs;
        /* number of interfaces with corresponding FIF_ flags */
        int fif_fcsfail, fif_plcpfail, fif_control, fif_other_bss;
        unsigned int filter_flags; /* FIF_* */

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 3a3112f17832a3767095cfb2ebcdc70676816583..b1fc112152c9f2b0389d6f19810301f250d5cbcc 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -223,6 +223,9 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
                if (sdata->vif.type != IEEE80211_IF_TYPE_MNTR)
                        continue;
 
+               if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
+                       continue;
+
                if (prev_dev) {
                        skb2 = skb_clone(skb, GFP_ATOMIC);
                        if (skb2) {
@@ -1520,6 +1523,86 @@ static void ieee80211_rx_michael_mic_report(struct net_device *dev,
        rx->skb = NULL;
 }
 
+static void ieee80211_rx_cooked_monitor(struct ieee80211_txrx_data *rx)
+{
+       struct ieee80211_sub_if_data *sdata;
+       struct ieee80211_local *local = rx->local;
+       struct ieee80211_rtap_hdr {
+               struct ieee80211_radiotap_header hdr;
+               u8 flags;
+               u8 rate;
+               __le16 chan_freq;
+               __le16 chan_flags;
+       } __attribute__ ((packed)) *rthdr;
+       struct sk_buff *skb = rx->skb, *skb2;
+       struct net_device *prev_dev = NULL;
+       struct ieee80211_rx_status *status = rx->u.rx.status;
+
+       if (rx->flags & IEEE80211_TXRXD_RX_CMNTR_REPORTED)
+               goto out_free_skb;
+
+       if (skb_headroom(skb) < sizeof(*rthdr) &&
+           pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC))
+               goto out_free_skb;
+
+       rthdr = (void *)skb_push(skb, sizeof(*rthdr));
+       memset(rthdr, 0, sizeof(*rthdr));
+       rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
+       rthdr->hdr.it_present =
+               cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
+                           (1 << IEEE80211_RADIOTAP_RATE) |
+                           (1 << IEEE80211_RADIOTAP_CHANNEL));
+
+       rthdr->rate = rx->u.rx.rate->bitrate / 5;
+       rthdr->chan_freq = cpu_to_le16(status->freq);
+
+       if (status->band == IEEE80211_BAND_5GHZ)
+               rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_OFDM |
+                                               IEEE80211_CHAN_5GHZ);
+       else
+               rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_DYN |
+                                               IEEE80211_CHAN_2GHZ);
+
+       skb_set_mac_header(skb, 0);
+       skb->ip_summed = CHECKSUM_UNNECESSARY;
+       skb->pkt_type = PACKET_OTHERHOST;
+       skb->protocol = htons(ETH_P_802_2);
+
+       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+               if (!netif_running(sdata->dev))
+                       continue;
+
+               if (sdata->vif.type != IEEE80211_IF_TYPE_MNTR ||
+                   !(sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES))
+                       continue;
+
+               if (prev_dev) {
+                       skb2 = skb_clone(skb, GFP_ATOMIC);
+                       if (skb2) {
+                               skb2->dev = prev_dev;
+                               netif_rx(skb2);
+                       }
+               }
+
+               prev_dev = sdata->dev;
+               sdata->dev->stats.rx_packets++;
+               sdata->dev->stats.rx_bytes += skb->len;
+       }
+
+       if (prev_dev) {
+               skb->dev = prev_dev;
+               netif_rx(skb);
+               skb = NULL;
+       } else
+               goto out_free_skb;
+
+       rx->flags |= IEEE80211_TXRXD_RX_CMNTR_REPORTED;
+       return;
+
+ out_free_skb:
+       dev_kfree_skb(skb);
+}
+
 typedef ieee80211_rx_result (*ieee80211_rx_handler)(struct ieee80211_txrx_data *);
 static ieee80211_rx_handler ieee80211_rx_handlers[] =
 {
@@ -1574,9 +1657,11 @@ static void ieee80211_invoke_rx_handlers(struct ieee80211_sub_if_data *sdata,
        }
 
        switch (res) {
+       case RX_CONTINUE:
        case RX_DROP_MONITOR:
+               ieee80211_rx_cooked_monitor(rx);
+               break;
        case RX_DROP_UNUSABLE:
-       case RX_CONTINUE:
                dev_kfree_skb(rx->skb);
                break;
        }